Capturing carbon dioxide

Abstract

Techniques for capturing carbon dioxide (CO2) from atmospheric air include flowing the atmospheric air along a flow path comprising at least one energy transfer module, transferring energy from the at least one energy transfer module to the atmospheric air to form a CO2-rich gas stream in the flow path, flowing the CO2-rich gas stream along a gas-liquid interface in the flow path, flowing a CO2 capture solution along the gas-liquid interface to absorb CO2 from the CO2-rich gas stream into the CO2 capture solution and to form a CO2-lean gas stream, transferring energy from the CO2-lean gas stream to the at least one energy transfer module to form an exhaust CO2-lean gas stream.

Description

Attorney Docket No.: 30285-0050W01CAPTURING CARBON DIOXIDETECHNICAL FIELD

[0001] This disclosure describes systems, apparatus, and methods for capturing carbon dioxide and, more particularly, managing a carbon dioxide capture fluid in a direct air contactor.BACKGROUND

[0002] Capturing carbon dioxide (CO2) from the atmosphere is one approach to mitigating greenhouse gas emissions and slowing climate change. However, many technologies designed for CO2 capture from point sources of emissions, such as from flue gas of industrial facilities, are generally ineffective in capturing CO2 from the atmosphere due to the significantly lower CO2 concentrations and large volumes of atmospheric air required to process. In recent years, progress has been made in finding technologies better suited to capture CO2 directly from the atmosphere. Some of these direct air capture (DAC) systems use a solid sorbent where an active agent is attached to a substrate. These DAC systems typically employ a cyclic adsorption-desorption process where, after the solid sorbent is saturated with CO2, it releases the CO2 using a humidity or thermal swing and is regenerated.

[0003] Other DAC systems use a liquid sorbent (sometimes referred to as a solvent) to capture CO2 from the atmosphere. An example of such a DAC system would be one where a fan is used to draw air across a high surface area packing that is wetted with a solution comprising the liquid sorbent. CO2 in the air reacts with the liquid sorbent to generate a CO2 rich solution. The rich solution is processed to regenerate a lean solution and to release a concentrated carbon stream, for example, CO, CO2 or other carbon products.SUMMARY

[0004] In an example implementation, a gas-liquid contactor for capturing carbon dioxide (CO2) from atmospheric air includes at least one inlet; at least one outlet spaced apart from the at least one inlet; a gas-liquid interface positioned between the at least one inlet and the at least one outlet; a liquid distribution system configured to flow a CO2 capture solution along the gas-liquid interface; at least one fan configured to flow atmospheric air along a flow path from the at least one inlet, along the gas-liquid interface, and to the at least one outlet, to contact the atmosphericAttorney Docket No.: 30285-0050W01 air with the CO2 capture solution, thereby absorbing CO2 from the atmospheric air into the CO2 capture solution to form a CCh-lean gas stream flowable through the at least one outlet; and at least one energy transfer module positioned in the flow path. The at least one energy transfer module includes a plurality of energy transfer channels configured to transfer energy between the CO2- lean gas stream and the flow of atmospheric air. The plurality of energy transfer channels define a first airflow circuit that includes a first airflow inlet positioned to receive the flow of atmospheric air from the at least one inlet and a first airflow outlet fluidly coupled to the first airflow inlet; and a second airflow circuit fluidly separated from the first airflow circuit and including a second airflow inlet and a second airflow outlet fluidly coupled to the second airflow inlet and positioned to exhaust the CCh-lean gas stream to the at least one outlet.

[0005] In an aspect combinable with the example implementation, the at least one energy transfer module includes at least one enthalpy transfer module, and the plurality of energy transfer channels are configured to transfer enthalpy from the CCh-lean gas stream to the flow of atmospheric air.

[0006] In another aspect combinable with one, some, or all of the previous aspects, the transferred energy includes moisture transferred from the CCh-lean gas stream to the flow of atmospheric air; and a heat of absorption from the plurality of energy transfer channels to the flow of atmospheric air.

[0007] In another aspect combinable with one, some, or all of the previous aspects, the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first dry bulb temperature and output a CCh-rich gas stream from the first airflow outlet at a second dry bulb temperature greater than the first dry bulb temperature; and the second airflow circuit is configured to receive the CCh-lean gas stream into the second airflow inlet at a third dry bulb temperature and output an exhaust CCh-lean gas stream from the second airflow outlet at a fourth dry bulb temperature less than the third dry bulb temperature.

[0008] In another aspect combinable with one, some, or all of the previous aspects, the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first relative humidity and output the flow of atmospheric air from the first airflow outlet at a second relative humidity greater than the first relative humidity; and the second airflow circuit is configured to receive the CCh-lean gas stream through the second airflow inlet at a third relativeAttorney Docket No.: 30285-0050W01 humidity and output the CCh-lean gas stream from the second airflow outlet at a fourth relative humidity less than the third relative humidity.

[0009] In another aspect combinable with one, some, or all of the previous aspects, the at least one energy transfer module includes a first energy transfer module positioned in the flow path, the first energy transfer module including the first airflow circuit, the second airflow circuit, and the plurality of energy transfer channels include a first plurality of energy transfer channels; and a second energy transfer module positioned in the flow path, the second energy transfer module including a second plurality of energy transfer channels configured to transfer energy between the CCh-lean gas stream and the flow of atmospheric air.

[0010] In another aspect combinable with one, some, or all of the previous aspects, the second plurality of energy transfer channels define a third airflow circuit that includes a third airflow inlet positioned to receive the flow of atmospheric air from the first airflow outlet and a third airflow outlet fluidly coupled to the third airflow inlet; and a fourth airflow circuit that includes a fourth airflow inlet and a fourth airflow outlet fluidly coupled to the fourth airflow inlet and positioned to exhaust the CCh-lean gas stream to the second airflow inlet.

[0011] In another aspect combinable with one, some, or all of the previous aspects, the first energy transfer module includes a thermal energy transfer module, and the second energy transfer module includes a chemical energy transfer module.

[0012] In another aspect combinable with one, some, or all of the previous aspects, the first plurality of energy transfer circuits are configured to transfer sensible heat from the CCh-lean gas stream to the flow of atmospheric air; and the second plurality of energy transfer circuits are configured to transfer moisture from the CCh-lean gas stream to the flow of atmospheric air.

[0013] In another aspect combinable with one, some, or all of the previous aspects, the transferred enthalpy includes moisture transferred from the CCh-lean gas stream to the flow of atmospheric air; and a heat of absorption from the second plurality of energy transfer channels to the flow of atmospheric air.

[0014] In another aspect combinable with one, some, or all of the previous aspects, the gas-liquid contactor includes at least one heater positioned between the first airflow outlet and the third airflow inlet, the at least one heater configured to heat the flow of atmospheric air from the first airflow outlet to the third airflow inlet.Attorney Docket No.: 30285-0050W01

[0015] In another aspect combinable with one, some, or all of the previous aspects, the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first relative humidity, and the third airflow circuit is configured to output the flow of atmospheric air from the third airflow outlet at a second relative humidity greater than the first relative humidity; the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first temperature and output the flow of atmospheric air from the first airflow outlet at a second temperature greater than the first temperature; the fourth airflow circuit is configured to receive the CCh-lean gas stream through the fourth airflow inlet at a third relative humidity, and the second airflow circuit is configured to output the CCh-lean gas stream from the second airflow outlet at a fourth relative humidity less than the third relative humidity; and the fourth airflow circuit is configured to receive the CCh-lean gas stream through the fourth airflow inlet at a third temperature, and the second airflow circuit is configured to output the CO2- lean gas stream exits the second airflow outlet at a fourth temperature less than the third temperature.

[0016] In another aspect combinable with one, some, or all of the previous aspects, the gas-liquid contactor includes a control system communicably coupled to the at least one heater and configured to perform operations including controlling the at least one heater to add heat to the flow of atmospheric air between the first airflow outlet and the third airflow inlet such that the fourth relative humidity is less than the first relative humidity.

[0017] In another aspect combinable with one, some, or all of the previous aspects, the first energy transfer module includes a chemical energy transfer module, and the second energy transfer module includes a thermal energy transfer module.

[0018] In another aspect combinable with one, some, or all of the previous aspects, the first plurality of energy transfer channels are configured to transfer moisture from the CCh-lean gas stream to the flow of atmospheric air; and the second plurality of energy transfer channels are configured to transfer sensible heat from the CC -lean gas stream to the flow of atmospheric air.

[0019] In another aspect combinable with one, some, or all of the previous aspects, the transferred energy includes moisture transferred from the CCh-lean gas stream to the flow of atmospheric air; and a heat of absorption from the first plurality of energy transfer channels to the flow of atmospheric air.Attorney Docket No.: 30285-0050W01

[0020] In another aspect combinable with one, some, or all of the previous aspects, the gas-liquid contactor includes at least one heater positioned within a volume of the CO2 capture solution and configured to heat the volume of the CO2 capture solution.

[0021] In another aspect combinable with one, some, or all of the previous aspects, the gas-liquid contactor includes a basin configured to collect the CO2 capture solution from the gasliquid interface, the at least one heater being positioned within the basin.

[0022] In another aspect combinable with one, some, or all of the previous aspects, the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first relative humidity, and the third airflow circuit is configured to output the flow of atmospheric air from the third airflow outlet at a second relative humidity greater than the first relative humidity; the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first temperature, and the third airflow circuit is configured to output the flow of atmospheric air from the third airflow outlet at a second temperature greater than the first temperature; the fourth airflow circuit is configured to receive the CCh-lean gas stream through the fourth airflow inlet at a third relative humidity, and the second airflow circuit is configured to output the CCh-lean gas stream from the second airflow outlet at a fourth relative humidity less than the third relative humidity; and the fourth airflow circuit is configured to receive the CCh-lean gas stream enters the fourth airflow inlet at a third temperature and output the CO2- lean gas stream from the fourth airflow outlet at a fourth temperature less than the third temperature.

[0023] In another aspect combinable with one, some, or all of the previous aspects, the at least one energy transfer module includes a third energy transfer module positioned in the flow path, the third energy transfer module including a third plurality of energy transfer channels configured to transfer energy between the CCh-lean gas stream and the flow of atmospheric air, the third plurality of energy transfer channels defining: a fifth airflow circuit that includes a fifth airflow inlet positioned to receive the flow of atmospheric air from the third airflow outlet and a fifth airflow outlet fluidly coupled to the fifth airflow inlet; and a sixth airflow circuit that includes a sixth airflow inlet and a sixth airflow outlet fluidly coupled to the sixth airflow inlet and positioned to exhaust the CCh-lean gas stream to the fourth airflow inlet.

[0024] In another aspect combinable with one, some, or all of the previous aspects, the third energy transfer module includes a thermal energy transfer module.Attorney Docket No.: 30285-0050W01

[0025] In another aspect combinable with one, some, or all of the previous aspects, the third plurality of energy transfer channels are configured to transfer sensible heat from the CO2- lean gas stream to the flow of atmospheric air.

[0026] In another aspect combinable with one, some, or all of the previous aspects, the gas-liquid contactor includes at least one heater positioned between the first airflow outlet and the third airflow inlet, the at least one heater configured to heat the flow of atmospheric air from the first airflow outlet to the third airflow inlet.

[0027] In another aspect combinable with one, some, or all of the previous aspects, the gas-liquid contactor includes at least one basin heater positioned within a basin configured to collect the CO2 capture solution from the gas-liquid interface, the at least one basin heater configured to heat a volume of the CO2 capture solution.

[0028] In another aspect combinable with one, some, or all of the previous aspects, the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first relative humidity, and the third airflow circuit is configured to output the flow of atmospheric air from the third airflow outlet at a second relative humidity greater than the first relative humidity; the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first temperature, and the third airflow circuit is configured to output the flow of atmospheric air from the third airflow outlet at a second temperature greater than the first temperature; the sixth airflow circuit is configured to receive the CCh-lean gas stream through the sixth airflow inlet at a third relative humidity, and the second airflow circuit is configured to output the CCh-lean gas stream from the second airflow outlet at a fourth relative humidity less than the third relative humidity; and the sixth airflow circuit is configured to receive the CCh-lean gas stream through the sixth airflow inlet at a third temperature, and the second airflow circuit is configured to output the CCh-lean gas stream exits the second airflow outlet at a fourth temperature less than the third temperature.

[0029] In another aspect combinable with one, some, or all of the previous aspects, the gas-liquid contactor includes a control system communicably coupled to the at least one heater and configured to perform operations including controlling the at least one heater to add heat to the flow of atmospheric air between the third airflow outlet and the fifth airflow inlet such that the fourth relative humidity is less than the first relative humidity.Attorney Docket No.: 30285-0050W01

[0030] In another aspect combinable with one, some, or all of the previous aspects, adjacent energy transfer channels of the plurality of energy transfer channels are annular airflow channels circumscribing a radial center.

[0031] In another aspect combinable with one, some, or all of the previous aspects, the annular airflow channels are defined by a plurality of annular sheets.

[0032] In another aspect combinable with one, some, or all of the previous aspects, the plurality of annular sheets includes an energy transfer material being configured to transfer at least one of thermal energy or chemical energy.

[0033] In another aspect combinable with one, some, or all of the previous aspects, the energy transfer material is a coating on at least one annular sheet of the plurality of annular sheets.

[0034] In another aspect combinable with one, some, or all of the previous aspects, the at least one energy transfer module includes a thermal wheel that defines a wheel axis having a vertical orientation, the thermal wheel configured to rotate about the wheel axis.

[0035] In another aspect combinable with one, some, or all of the previous aspects, the at least one energy transfer module includes a thermal wheel that defines a wheel axis having a vertical orientation, the thermal wheel configured to rotate about the wheel axis, and the thermal wheel includes a plurality of annular sheets being concentric about the wheel axis, each annular sheet of the plurality of annular sheets spaced apart from another annular sheet of the plurality of annular sheets in a direction radial to the wheel axis.

[0036] In another aspect combinable with one, some, or all of the previous aspects, each energy transfer circuit of the plurality of energy transfer circuits includes a circumferential air passage defined between adjacent annular sheets of the plurality of annular sheets.

[0037] In another aspect combinable with one, some, or all of the previous aspects, at least one annular sheet of the plurality of annular sheets includes corrugated metal.

[0038] In another aspect combinable with one, some, or all of the previous aspects, the plurality of annular sheets includes a desiccant coating.

[0039] In another aspect combinable with one, some, or all of the previous aspects, adjacent energy transfer channels of the plurality of energy transfer channels are defined by a plurality of adjacent energy transfer units operatively connected to one another to form a belt-like structure being translatable across the flow path.Attorney Docket No.: 30285-0050W01

[0040] In another aspect combinable with one, some, or all of the previous aspects, the gas-liquid contactor includes an external drive to actuate translation of the plurality of adjacent energy transfer units across the flow path.

[0041] In another aspect combinable with one, some, or all of the previous aspects, the plurality of energy transfer units form a loop having an upper belt section and a lower belt section, and each energy transfer unit of the plurality of energy transfer units is translated across the flow path a first time in a first direction when part of the upper belt section and a second time in a second direction when part of the lower belt section, the second direction being the opposite of the first direction.

[0042] In another aspect combinable with one, some, or all of the previous aspects, the plurality of energy transfer units includes a plurality of inlet energy transfer units including the energy transfer channels defining the first airflow circuit receiving the flow of atmospheric air; and a plurality of outlet energy transfer units including the energy transfer channels defining the second airflow circuit receiving the CCh-lean gas stream.

[0043] In another aspect combinable with one, some, or all of the previous aspects, the first airflow circuit extends over an entire surface of the at least one inlet, and the second airflow circuit extends over an entire surface of the at least one outlet.

[0044] In another aspect combinable with one, some, or all of the previous aspects, each energy transfer unit defines a gap or an enclosure that is sized and shaped to receive an energy transfer material, the gap or the enclosure of the energy transfer units configured to provide the plurality of energy transfer channels.

[0045] In another aspect combinable with one, some, or all of the previous aspects, the at least one inlet includes at least one vertical inlet, and the at least one outlet includes at least one vertical outlet spaced apart from the at least one vertical inlet, and the at least one energy transfer module is positioned to intersect the flow path in the at least one vertical inlet and the at least one vertical outlet.

[0046] In another aspect combinable with one, some, or all of the previous aspects, the at least one inlet includes at least one vertical inlet, and the at least one outlet includes at least one vertical outlet spaced apart from the at least one vertical inlet and separated by the gas-liquid interface, and the at least one energy transfer module is positioned to intersect the flow path in the at least one vertical inlet and the at least one vertical outlet.Attorney Docket No.: 30285-0050W01

[0047] In another aspect combinable with one, some, or all of the previous aspects, the gas-liquid interface is configured to contact the atmospheric air with the CO2 capture solution in a cross-flow arrangement, a co-current flow arrangement, or a counter-current flow arrangement.

[0048] In another aspect combinable with one, some, or all of the previous aspects, the gas-liquid interface includes at least one packing.

[0049] In another example implementation, a method for capturing carbon dioxide (CO2) from atmospheric air includes flowing the atmospheric air into an inlet of a flow path including at least one energy transfer module; transferring energy from the at least one energy transfer module to the atmospheric air to form a CCh-rich gas stream in the flow path; flowing the CCh-rich gas stream along a gas-liquid interface in the flow path; flowing a CO2 capture solution along the gasliquid interface to absorb CO2 from the CCh-rich gas stream into the CO2 capture solution and to form a CCh-lean gas stream; transferring energy from the CCh-lean gas stream to the at least one energy transfer module to form an exhaust CCh-lean gas stream; and flowing the exhaust CCh-lean gas stream from an outlet the flow path.

[0050] In an aspect combinable with the example implementation, transferring energy from the at least one energy transfer module to the atmospheric air or transferring energy from the CCh-lean gas stream to the at least one energy transfer module includes transferring at least one of thermal energy or chemical energy.

[0051] In another aspect combinable with one, some, or all of the previous aspects, transferring energy from the at least one energy transfer module to the atmospheric air or transferring energy from the CCh-lean gas stream to the at least one energy transfer module includes transferring enthalpy.

[0052] In another aspect combinable with one, some, or all of the previous aspects, transferring energy from the at least one energy transfer module to the atmospheric air or transferring energy from the CCh-lean gas stream to the at least one energy transfer module includes transferring moisture from the CCh-lean gas stream to the flow of atmospheric air; and transferring a heat of absorption from the at least one energy transfer module to the flow of atmospheric air.

[0053] In another aspect combinable with one, some, or all of the previous aspects, the method includes flowing the atmospheric air into the at least one energy transfer module at a first dry bulb temperature; flowing the CCh-rich gas stream out of the at least one energy transferAttorney Docket No.: 30285-0050W01 module at a second dry bulb temperature greater than the first dry bulb temperature; and flowing the CCh-lean gas stream into the at least one energy transfer module at a third dry bulb temperature; and flowing the exhaust CCh-lean gas stream out of the at least one energy transfer module at a fourth dry bulb temperature less than the third dry bulb temperature.

[0054] In another aspect combinable with one, some, or all of the previous aspects, the method includes flowing the atmospheric air into the at least one energy transfer module at a first relative humidity; flowing the CCh-rich gas stream out of the at least one energy transfer module at a second relative humidity greater than the first relative humidity; flowing the CCh-lean gas stream into the at least one energy transfer module at a third relative humidity; and flowing the exhaust CCh-lean gas stream out of the at least one energy transfer module at a fourth relative humidity less than the third relative humidity.

[0055] In another aspect combinable with one, some, or all of the previous aspects, the at least one energy transfer module includes a first energy transfer module positioned in the flow path and a second energy transfer module positioned in the flow path in fluid communication with the first energy transfer module.

[0056] In another aspect combinable with one, some, or all of the previous aspects, transferring energy from the at least one energy transfer module to the atmospheric air or transferring energy from the CCh-lean gas stream to the at least one energy transfer module includes transferring sensible heat from the CCh-lean gas stream to the flow of atmospheric air with the first energy transfer module.

[0057] In another aspect combinable with one, some, or all of the previous aspects, transferring energy from the at least one energy transfer module to the atmospheric air or transferring energy from the CCh-lean gas stream to the at least one energy transfer module includes transferring moisture from the CCh-lean gas stream to the flow of atmospheric air with the second energy transfer module.

[0058] In another aspect combinable with one, some, or all of the previous aspects, transferring energy from the at least one energy transfer module to the atmospheric air or transferring energy from the CCh-lean gas stream to the at least one energy transfer module includes transferring moisture from the CCh-lean gas stream to the flow of atmospheric air by the first energy transfer module; and transferring a heat of absorption from the second energy transfer module to the flow of atmospheric air.Attorney Docket No.: 30285-0050W01

[0059] In another aspect combinable with one, some, or all of the previous aspects, the method includes heating the flow of atmospheric air between the first and second energy transfer modules with at least one heater positioned along the flow path.

[0060] In another aspect combinable with one, some, or all of the previous aspects, the method includes flowing the atmospheric air into the first energy transfer module at a first relative humidity; flowing the CCh-rich gas stream out of the second energy transfer module at a second relative humidity greater than the first relative humidity; flowing the atmospheric air into the first energy transfer module at a first temperature; flowing the CCh-rich gas stream out of the second energy transfer module at a second temperature greater than the first temperature; flowing the CO2- lean gas stream into the second energy transfer module at a third relative humidity; flowing the exhaust CCh-lean gas stream out of the first energy transfer module at a fourth relative humidity less than the third relative humidity; flowing the CCh-lean gas stream into the second energy transfer module at a third temperature; and flowing the exhaust CCh-lean gas stream out of the first energy transfer module at a fourth temperature less than the third temperature.

[0061] In another aspect combinable with one, some, or all of the previous aspects, the method includes controlling the at least one heater to add heat to the CCh-rich gas stream between the first energy transfer module and the second energy transfer module and form a heated CO2- rich gas stream such that the fourth relative humidity is less than the first relative humidity.

[0062] In another aspect combinable with one, some, or all of the previous aspects, transferring energy from the at least one energy transfer module to the atmospheric air or transferring energy from the CCh-lean gas stream to the at least one energy transfer module includes transferring moisture from the CCh-lean gas stream to the flow of atmospheric air with the first energy transfer module.

[0063] In another aspect combinable with one, some, or all of the previous aspects, transferring energy from the at least one energy transfer module to the atmospheric air or transferring energy from the CCh-lean gas stream to the at least one energy transfer module includes transferring sensible heat from the CCh-lean gas stream to the flow of atmospheric air with the second energy transfer module.

[0064] In another aspect combinable with one, some, or all of the previous aspects, transferring energy from the at least one energy transfer module to the atmospheric air or transferring energy from the CCh-lean gas stream to the at least one energy transfer moduleAttorney Docket No.: 30285-0050W01 includes transferring moisture from the CCh-lean gas stream to the flow of atmospheric air; and transferring a heat of absorption from the first energy transfer module to the flow of atmospheric air.

[0065] In another aspect combinable with one, some, or all of the previous aspects, the method includes heating a volume of the CO2 capture solution with at least one heater positioned within the volume of the CO2 capture solution.

[0066] In another aspect combinable with one, some, or all of the previous aspects, the method includes collecting the CO2 capture solution from the gas-liquid interface in a basin of the gas-liquid contactor.

[0067] In another aspect combinable with one, some, or all of the previous aspects, the method includes flowing the atmospheric air into the first energy transfer module at a first relative humidity; flowing the CCh-rich gas stream out of the second energy transfer module at a second relative humidity greater than the first relative humidity; flowing the atmospheric air into the first energy transfer module at a first temperature; flowing the C Ch-rich gas stream out of the second energy transfer module at a second temperature greater than the first temperature; flowing the CO2- lean gas stream into the second energy transfer module at a third relative humidity; flowing the exhaust CCh-lean gas stream out of the first energy transfer module at a fourth relative humidity less than the third relative humidity; flowing the CCh-lean gas stream into the second energy transfer module at a third temperature; and flowing the exhaust CCh-lean gas stream out of the first energy transfer module at a fourth temperature less than the third temperature.

[0068] In another aspect combinable with one, some, or all of the previous aspects, the flow path includes a third energy transfer module, and the method includes transferring energy from the CCh-lean gas stream to the flow of atmospheric air with the third energy transfer module.

[0069] In another aspect combinable with one, some, or all of the previous aspects, transferring energy from the CCh-lean gas stream to the flow of atmospheric air with the third energy transfer module includes transferring enthalpy from the CCh-lean gas stream to the flow of atmospheric air with the third energy transfer module.

[0070] In another aspect combinable with one, some, or all of the previous aspects, transferring energy from the at least one energy transfer module to the atmospheric air or transferring energy from the CCh-lean gas stream to the at least one energy transfer module includes transferring moisture from the CCh-lean gas stream to the flow of atmospheric air; andAttorney Docket No.: 30285-0050W01 transferring a heat of absorption from the third energy transfer module to the flow of atmospheric air.

[0071] In another aspect combinable with one, some, or all of the previous aspects includes heating the CCh-rich gas stream with at least one heater positioned between the second energy transfer module and the third energy transfer module.

[0072] In another aspect combinable with one, some, or all of the previous aspects, the method includes flowing the atmospheric air into the first energy transfer module at a first relative humidity; flowing the atmospheric air from the first energy transfer module at a second relative humidity greater than the first relative humidity; flowing the atmospheric air into the first energy transfer module at a first temperature; flowing the CCh-rich gas stream out of the first energy transfer module at a second temperature greater than the first temperature; flowing the C Ch-lean gas stream into the third energy transfer module at a third relative humidity; flowing the exhaust CCh-lean gas stream out of the first energy transfer module at a fourth relative humidity less than the third relative humidity; flowing the CCh-lean gas stream into the third energy transfer module at a third temperature; and flowing the exhaust CCh-lean gas stream out of the first energy transfer module at a fourth temperature less than the third temperature.

[0073] In another aspect combinable with one, some, or all of the previous aspects, the method includes controlling the at least one heater to add heat to the CCh-rich gas stream between the second energy transfer module and the third energy transfer module such that the fourth relative humidity is less than the first relative humidity.

[0074] In another aspect combinable with one, some, or all of the previous aspects, the method includes moving the at least one energy transfer module between the inlet of the flow path and the outlet of the flow path to transfer the energy between the CCh-lean gas stream and the flow of atmospheric air through the at least one energy transfer module being positioned in the flow path.

[0075] In another aspect combinable with one, some, or all of the previous aspects, moving the at least one energy transfer module between the inlet of the flow path and the outlet of the flow path includes rotating the at least one energy transfer module about an axis that has a vertical orientation and extends through a radial center of the at least one energy transfer module.

[0076] In another aspect combinable with one, some, or all of the previous aspects, moving the at least one energy transfer module between the inlet of the flow path and the outlet of the flowAttorney Docket No.: 30285-0050W01 path including translating the at least one energy transfer module across the flow path in a first direction from the inlet to the outlet of the flow path to contact the flow of atmospheric air and in a second direction from the outlet to the inlet of the flow path to contact the CCh-lean gas stream.

[0077] In another aspect combinable with one, some, or all of the previous aspects, transferring energy from the at least one energy transfer module to the atmospheric air or transferring energy from the CCh-lean gas stream to the at least one energy transfer module includes flowing the atmospheric air or the CCh-lean gas stream through a plurality of energy transfer channels of the at least one energy transfer module.

[0078] In another aspect combinable with one, some, or all of the previous aspects, flowing the atmospheric air or the CCh-lean gas stream through the plurality of energy transfer channels includes contacting an energy transfer material being configured to transfer at least one of thermal energy or chemical energy.

[0079] In another aspect combinable with one, some, or all of the previous aspects, flowing the CO2 capture solution along the gas-liquid interface to absorb CO2 from the CCh-rich gas stream into the CO2 capture solution includes contacting CO2 in the CCh-rich gas stream with an amine solution to form a CCh-rich slurry including at least one of carbon containing solids or carbamic acid solids.

[0080] In another aspect combinable with one, some, or all of the previous aspects, contacting CO2 in the CCh-rich gas stream with the amine solution includes contacting CO2 in the CCh-rich gas stream with 3-(aminomethyl)-3,5,5-trimethylcyclohexylamine (IPDA).

[0081] In another aspect combinable with one, some, or all of the previous aspects, contacting CO2 in the CCh-rich gas stream with the amine solution includes contacting CO2 in the CCh-rich gas stream with a diamine with an aminocyclic compound group.

[0082] In another aspect combinable with one, some, or all of the previous aspects, contacting CO2 in the CCh-rich gas stream with the diamine includes contacting CO2 in the CCh- rich gas stream with a cyclohexane-l,3-diamine-5 R X.

[0083] In another aspect combinable with one, some, or all of the previous aspects, R is a hydrocarbon chain and X is an amino group, and X functionalizes the cyclohexane or the R hydrocarbon chain.Attorney Docket No.: 30285-0050W01

[0084] In another aspect combinable with one, some, or all of the previous aspects, contacting CO2 in the CCh-rich gas stream with the diamine includes contacting CO2 in the CO2- rich gas stream with a cyclohexane-l,3-diamine-5 R, where R is a hydrocarbon chain.

[0085] In another aspect combinable with one, some, or all of the previous aspects, R is butane, pentane, hexane, or cycloalkane.

[0086] In another aspect combinable with one, some, or all of the previous aspects, flowing the CO2 capture solution along the gas-liquid interface to absorb CO2 from the CCh-rich gas stream into the CO2 capture solution includes contacting CO2 in the CCh-rich gas stream with a guanidine- based solution to form a CCh-rich slurry including carbonate solids.

[0087] In another aspect combinable with one, some, or all of the previous aspects, the guanidine-based solution includes a bis-iminoguanidine.

[0088] In another aspect combinable with one, some, or all of the previous aspects, the bis- iminoguanidine is 2,5-furan-bis-(iminoguanidine) (FuBIG).

[0089] In another aspect combinable with one, some, or all of the previous aspects, flowing the CO2 capture solution along the gas-liquid interface to absorb CO2 from the CCh-rich gas stream into the CO2 capture solution includes contacting CO2 in the CCh-rich gas stream with the CO2 capture solution including an alkali metal sorbent to form a CCh-rich capture solution.

[0090] In another aspect combinable with one, some, or all of the previous aspects, the method includes promoting precipitation of solids in suspension in the CCh-rich capture solution with an amine species being present in the CCh-rich capture solution in addition to the alkali metal sorbent.

[0091] In another aspect combinable with one, some, or all of the previous aspects, the method includes flowing the CCh-lean gas stream in a wash section provided along the flow path and downstream of the at least one gas-liquid interface, the wash section being configured to remove aerosolized particles and / or volatilized components of the CO2 capture solution from the CCh-lean gas stream.

[0092] In another example implementation, a direct air capture (DAC) system for capturing carbon dioxide (CO2) from atmospheric air includes at least one gas-liquid contactor defining at least a portion of a flow path. The at least one gas-liquid contactor includes at least one inlet; at least one outlet spaced apart from the at least one inlet; a gas-liquid interface disposed between the at least one inlet and the at least one outlet; a liquid distribution system configured toAttorney Docket No.: 30285-0050W01 flow a CO2 capture solution along the gas-liquid interface; at least one fan configured to flow atmospheric air along the flow path from the at least one inlet, along the gas-liquid interface, and to the at least one outlet, to contact the atmospheric air with the CO2 capture solution and absorb CO2 from the atmospheric air into the CO2 capture solution to form a CCh-lean gas stream flowable through the at least one outlet; and at least one energy transfer module. The at least one energy transfer module includes a plurality of energy transfer channels configured to transfer energy between the CCh-lean gas stream and the flow of atmospheric air along the flow path. The plurality of energy transfer channels define a first airflow circuit that includes a first airflow inlet positioned to receive the flow of atmospheric air and a first airflow outlet fluidly coupled to the first airflow inlet; and a second airflow circuit fluidly separated from the first airflow circuit and including a second airflow inlet and a second airflow outlet fluidly coupled to the second airflow inlet and positioned to exhaust the CCh-lean gas stream from the DAC system.

[0093] In an aspect combinable with the example implementation, the at least one energy transfer module includes at least one enthalpy transfer module, and the plurality of energy transfer channels are configured to transfer enthalpy from the CCh-lean gas stream to the flow of atmospheric air.

[0094] In another aspect combinable with one, some, or all of the previous aspects, the at least one energy transfer module including the plurality of energy transfer channels is configured to transfer energy that includes moisture transferred from the CCh-lean gas stream to the flow of atmospheric air; and a heat of absorption from the plurality of energy transfer channels to the flow of atmospheric air.

[0095] In another aspect combinable with one, some, or all of the previous aspects, the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first dry bulb temperature and output a C Ch-rich gas stream from the first airflow outlet at a second dry bulb temperature greater than the first dry bulb temperature; and the second airflow circuit is configured to receive the CCh-lean gas stream into the second airflow inlet at a third dry bulb temperature and output an exhaust CCh-lean gas stream from the second airflow outlet at a fourth dry bulb temperature less than the third dry bulb temperature.

[0096] In another aspect combinable with one, some, or all of the previous aspects, the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first relative humidity and output the flow of atmospheric air from the first airflow outlet at aAttorney Docket No.: 30285-0050W01 second relative humidity greater than the first relative humidity; and the second airflow circuit is configured to receive the CCh-lean gas stream through the second airflow inlet at a third relative humidity and output the CCh-lean gas stream from the second airflow outlet at a fourth relative humidity less than the third relative humidity.

[0097] In another aspect combinable with one, some, or all of the previous aspects, the at least one energy transfer module includes a first energy transfer module positioned in the flow path, the first energy transfer module including the first airflow circuit, the second airflow circuit, and the plurality of energy transfer channels include a first plurality of energy transfer channels; and a second energy transfer module positioned in the flow path, the second energy transfer module including a second plurality of energy transfer channels configured to transfer energy between the CCh-lean gas stream and the flow of atmospheric air.

[0098] In another aspect combinable with one, some, or all of the previous aspects, the second plurality of energy transfer channels define a third airflow circuit that includes a third airflow inlet positioned to receive the flow of atmospheric air from the first airflow outlet and a third airflow outlet fluidly coupled to the third airflow inlet; and a fourth airflow circuit that includes a fourth airflow inlet and a fourth airflow outlet fluidly coupled to the fourth airflow inlet and positioned to exhaust the CCh-lean gas stream to the second airflow inlet.

[0099] In another aspect combinable with one, some, or all of the previous aspects, the first energy transfer module includes a thermal energy transfer module, and the second energy transfer module includes a chemical energy transfer module.

[0100] In another aspect combinable with one, some, or all of the previous aspects, the first plurality of energy transfer circuits is configured to transfer sensible heat from the CCh-lean gas stream to the flow of atmospheric air; and the second plurality of energy transfer circuits is configured to transfer moisture from the CCh-lean gas stream to the flow of atmospheric air.

[0101] In another aspect combinable with one, some, or all of the previous aspects, the at least one energy transfer module is configured to transfer energy that includes moisture transferred from the CCh-lean gas stream to the flow of atmospheric air; and a heat of absorption from the second plurality of energy transfer channels to the flow of atmospheric air.

[0102] In another aspect combinable with one, some, or all of the previous aspects, the DAC system includes at least one heater positioned between the first airflow outlet and the thirdAttorney Docket No.: 30285-0050W01 airflow inlet, the at least one heater configured to heat the flow of atmospheric air from the first airflow outlet to the third airflow inlet.

[0103] In another aspect combinable with one, some, or all of the previous aspects, the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first relative humidity, and the third airflow circuit is configured to output the flow of atmospheric air from the third airflow outlet at a second relative humidity greater than the first relative humidity; the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first temperature and output the flow of atmospheric air from the first airflow outlet at a second temperature greater than the first temperature; the fourth airflow circuit is configured to receive the CCh-lean gas stream through the fourth airflow inlet at a third relative humidity, and the second airflow circuit is configured to output the CCh-lean gas stream from the second airflow outlet at a fourth relative humidity less than the third relative humidity; and the fourth airflow circuit is configured to receive the C Ch-lean gas stream through the fourth airflow inlet at a third temperature, and the second airflow circuit is configured to output the CO2- lean gas stream exits the second airflow outlet at a fourth temperature less than the third temperature.

[0104] In another aspect combinable with one, some, or all of the previous aspects, the DAC system includes a control system communicably coupled to the at least one heater and configured to perform operations including controlling the at least one heater to add heat to the flow of atmospheric air between the first airflow outlet and the third airflow inlet such that the fourth relative humidity is less than the first relative humidity.

[0105] In another aspect combinable with one, some, or all of the previous aspects, the first energy transfer module includes a chemical energy transfer module, and the second energy transfer module includes a thermal energy transfer module.

[0106] In another aspect combinable with one, some, or all of the previous aspects, the first plurality of energy transfer channels is configured to transfer moisture from the CCh-lean gas stream to the flow of atmospheric air; and the second plurality of energy transfer channels are configured to transfer sensible heat from the CCh-lean gas stream to the flow of atmospheric air.

[0107] In another aspect combinable with one, some, or all of the previous aspects, the at least one energy transfer module is configured to transfer energy that includes moisture transferredAttorney Docket No.: 30285-0050W01 from the CCh-lean gas stream to the flow of atmospheric air; and a heat of absorption from the first plurality of energy transfer channels to the flow of atmospheric air.

[0108] In another aspect combinable with one, some, or all of the previous aspects, the method includes at least one heater positioned within a volume of the CO2 capture solution and configured to heat the volume of the CO2 capture solution.

[0109] In another aspect combinable with one, some, or all of the previous aspects includes a basin configured to collect the CO2 capture solution from the gas-liquid interface, the at least one heater being positioned within the basin.

[0110] In another aspect combinable with one, some, or all of the previous aspects, the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first relative humidity, and the third airflow circuit is configured to output the flow of atmospheric air from the third airflow outlet at a second relative humidity greater than the first relative humidity; the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first temperature, and the third airflow circuit is configured to output the flow of atmospheric air from the third airflow outlet at a second temperature greater than the first temperature; the fourth airflow circuit is configured to receive the CCh-lean gas stream through the fourth airflow inlet at a third relative humidity, and the second airflow circuit is configured to output the CCh-lean gas stream from the second airflow outlet at a fourth relative humidity less than the third relative humidity; and the fourth airflow circuit is configured to receive the CCh-lean gas stream enters the fourth airflow inlet at a third temperature and output the CO2- lean gas stream from the fourth airflow outlet at a fourth temperature less than the third temperature.

[0111] In another aspect combinable with one, some, or all of the previous aspects, the at least one energy transfer module includes a third energy transfer module positioned in the flow path, the third energy transfer module including a third plurality of energy transfer channels configured to transfer energy between the CCh-lean gas stream and the flow of atmospheric air.

[0112] In another aspect combinable with one, some, or all of the previous aspects, the third plurality of energy transfer channels define a fifth airflow circuit that includes a fifth airflow inlet positioned to receive the flow of atmospheric air from the third airflow outlet and a fifth airflow outlet fluidly coupled to the fifth airflow inlet; and a sixth airflow circuit that includes aAttorney Docket No.: 30285-0050W01 sixth airflow inlet and a sixth airflow outlet fluidly coupled to the sixth airflow inlet and positioned to exhaust the CCh-lean gas stream to the fourth airflow inlet.

[0113] In another aspect combinable with one, some, or all of the previous aspects, the third energy transfer module includes an enthalpy transfer module.

[0114] In another aspect combinable with one, some, or all of the previous aspects, the third plurality of energy transfer channels are configured to transfer enthalpy from the CCh-lean gas stream to the flow of atmospheric air.

[0115] In another aspect combinable with one, some, or all of the previous aspects, the at least one energy transfer module is configured to transfer energy that includes moisture transferred from the CCh-lean gas stream to the flow of atmospheric air; and a heat of absorption from the third plurality of energy transfer channels to the flow of atmospheric air.

[0116] In another aspect combinable with one, some, or all of the previous aspects, the DAC system includes at least one heater positioned between the third airflow outlet and the fifth airflow inlet, the at least one heater configured to heat the flow of atmospheric air from the third airflow outlet to the fifth airflow inlet.

[0117] In another aspect combinable with one, some, or all of the previous aspects, the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first relative humidity, and the third airflow circuit is configured to output the flow of atmospheric air from the third airflow outlet at a second relative humidity greater than the first relative humidity; the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first temperature, and the third airflow circuit is configured to output the flow of atmospheric air from the third airflow outlet at a second temperature greater than the first temperature; the sixth airflow circuit is configured to receive the CCh-lean gas stream through the sixth airflow inlet at a third relative humidity, and the second airflow circuit is configured to output the CCh-lean gas stream from the second airflow outlet at a fourth relative humidity less than the third relative humidity; and the sixth airflow circuit is configured to receive the CCh-lean gas stream through the sixth airflow inlet at a third temperature, and the second airflow circuit is configured to output the CCh-lean gas stream exits the second airflow outlet at a fourth temperature less than the third temperature.

[0118] In another aspect combinable with one, some, or all of the previous aspects the DAC system includes a control system communicably coupled to the at least one heater andAttorney Docket No.: 30285-0050W01 configured to perform operations including controlling the at least one heater to add heat to the flow of atmospheric air between the third airflow outlet and the fifth airflow inlet such that the fourth relative humidity is less than the first relative humidity.

[0119] In another aspect combinable with one, some, or all of the previous aspects, adjacent energy transfer channels of the plurality of energy transfer channels are annular airflow channels circumscribing a radial center.

[0120] In another aspect combinable with one, some, or all of the previous aspects, the annular airflow channels are defined by a plurality of annular sheets.

[0121] In another aspect combinable with one, some, or all of the previous aspects, the plurality of annular sheets includes or is made of an energy transfer material being configured to transfer at least one of thermal energy or chemical energy.

[0122] In another aspect combinable with one, some, or all of the previous aspects, the energy transfer material is provided coated onto at least one annular sheet of the plurality of annular sheets.

[0123] In another aspect combinable with one, some, or all of the previous aspects, the at least one energy transfer module includes a thermal wheel that defines a wheel axis having a vertical orientation, the thermal wheel configured to rotate about the wheel axis.

[0124] In another aspect combinable with one, some, or all of the previous aspects, the at least one energy transfer module includes a thermal wheel that defines a wheel axis having a vertical orientation, with the thermal wheel configured to rotate about the wheel axis.

[0125] In another aspect combinable with one, some, or all of the previous aspects, the thermal wheel includes a plurality of annular sheets being concentric about the wheel axis, each annular sheet of the plurality of annular sheets spaced apart from another annular sheet of the plurality of annular sheets in a direction radial to the wheel axis, with each energy transfer circuit of the plurality of energy transfer circuits including a circumferential air passage defined between adjacent annular sheets of the plurality of annular sheets.

[0126] In another aspect combinable with one, some, or all of the previous aspects, at least one annular sheet of the plurality of annular sheets includes corrugated metal.

[0127] In another aspect combinable with one, some, or all of the previous aspects, the plurality of annular sheets includes a desiccant coating.Attorney Docket No.: 30285-0050W01

[0128] In another aspect combinable with one, some, or all of the previous aspects, adjacent energy transfer channels of the plurality of energy transfer channels are defined by a plurality of adjacent energy transfer units operatively connected to one another to form a belt-like structure being translatable across the flow path.

[0129] In another aspect combinable with one, some, or all of the previous aspects, the at least one energy transfer module includes an external drive to actuate translation of the plurality of adjacent energy transfer units across the flow path.

[0130] In another aspect combinable with one, some, or all of the previous aspects, the plurality of energy transfer units are organized as a loop, and each energy transfer unit of the plurality of energy transfer units is translated across the flow path a first time in a first direction and a second time in a second direction, with the second direction being the opposite of the first direction.

[0131] In another aspect combinable with one, some, or all of the previous aspects, the plurality of energy transfer units include a plurality of inlet energy transfer units including the energy transfer channels defining the first airflow circuit receiving the flow of atmospheric air; and a plurality of outlet energy transfer units including the energy transfer channels defining the second airflow circuit receiving the CCh-lean gas stream.

[0132] In another aspect combinable with one, some, or all of the previous aspects, the first airflow circuit extends over an entire surface of the at least one inlet, and the second airflow circuit extends over an entire surface of the at least one outlet.

[0133] In another aspect combinable with one, some, or all of the previous aspects, each energy transfer unit includes a pair of spaced-apart partitions protruding outwardly from a conveying surface, and two adjacent partitions at least partly define a gap or enclosure therebetween that is sized and shaped to receive a desiccant.

[0134] In another aspect combinable with one, some, or all of the previous aspects, the at least one energy transfer module is positioned in the flow path to have the first airflow circuit upstream of the gas-liquid interface and the second airflow circuit downstream of the gas-liquid interface.

[0135] In another aspect combinable with one, some, or all of the previous aspects, the at least one inlet includes at least one vertical inlet, and the at least one outlet includes at least one vertical outlet spaced apart from the at least one vertical inlet and separated by the gas-liquidAttorney Docket No.: 30285-0050W01 interface, and the at least one energy transfer module is positioned to intersect the flow path in the at least one vertical inlet and the at least one vertical outlet.

[0136] In another aspect combinable with one, some, or all of the previous aspects, the at least one energy transfer module is provided as part of the gas-liquid contactor, with an inlet of the flow path corresponding to the at least one inlet of the gas-liquid contactor, and an outlet of the flow path corresponding to the at least one outlet of the gas-liquid contactor.

[0137] In another aspect combinable with one, some, or all of the previous aspects, first airflow circuit is positioned upstream of the at least one inlet of the gas-liquid contactor and the second airflow circuit is positioned downstream of the at least one outlet of the gas-liquid contactor.

[0138] In another aspect combinable with one, some, or all of the previous aspects, the at least one energy transfer module is provided separately from the gas-liquid contactor, with the at least one energy transfer module being fluidly connected to the gas-liquid contactor via an interconnecting duct network further defining the flow path.

[0139] In another aspect combinable with one, some, or all of the previous aspects, the gas-liquid contactor includes a second gas-liquid interface being positioned downstream of the gas-liquid interface along the flow path; and a wash water distribution system to provide wash water along the second gas-liquid interface, the second gas-liquid interface serving as a wash section of the gas-liquid contactor and being configured to remove volatilized components and / or aerosolized particles of the CO2 capture solution from the CCh-lean gas stream.

[0140] In another aspect combinable with one, some, or all of the previous aspects, the gas-liquid interface is configured to contact the atmospheric air with the CO2 capture solution in a cross-flow arrangement, a co-current flow arrangement, or a counter-current flow arrangement.

[0141] In another aspect combinable with one, some, or all of the previous aspects, the gas-liquid interface includes at least one packing.

[0142] In another example implementation, a gas-liquid contactor for capturing carbon dioxide (CO2) from atmospheric air includes at least one inlet plenum extending from at least one inlet; at least one gas-liquid interface downstream of the at least one inlet plenum; at least one outlet plenum downstream of the at least one gas-liquid interface and extending to at least one outlet, the at least one outlet plenum being fluidly connected to the at least one inlet plenum through the at least one gas-liquid interface; a liquid distribution system configured to flow a CO2Attorney Docket No.: 30285-0050W01 capture solution along the at least one gas-liquid interface; at least one transfer wheel defining a wheel axis and rotatable about the wheel axis to: rotate a transfer wheel portion across the at least one inlet plenum and rotate a capture wheel portion across at least a portion of the at least one outlet plenum; and at least one fan defining a fan axis and rotatable about the fan axis to flow: atmospheric air along a first flow direction from the at least one inlet, through the at least one inlet plenum, and through the transfer wheel portion, to transfer at least one of moisture and thermal energy to the atmospheric air and form a CCh-rich gas stream; atmospheric air along the at least one gas-liquid interface to contact the CCh-rich gas stream with the CO2 capture solution, and absorb CO2 from the atmospheric air into the CO2 capture solution and form a CCh-lean gas stream; and the CCh-lean gas stream along a second flow direction through the at least one outlet plenum, through the capture wheel portion, and to the at least one outlet, to capture at least one of the moisture and the thermal energy from the CCh-lean gas stream, the second flow direction being opposite to the first flow direction.

[0143] In an aspect combinable with the example implementation, the gas-liquid contactor includes a dividing wall delimiting the at least one inlet plenum and the at least one outlet plenum.

[0144] In another aspect combinable with one, some, or all of the previous aspects, the dividing well has a vertical orientation, and extends downwardly from the at least one inlet to an upper portion of the at least one gas-liquid interface.

[0145] In another aspect combinable with one, some, or all of the previous aspects, the at least one gas-liquid interface includes an inlet portion disposed on one side of the dividing wall and in fluid communication with the at least one inlet plenum, and an outlet portion disposed on the other side of the dividing wall and in fluid communication with the at least one outlet plenum.

[0146] In another aspect combinable with one, some, or all of the previous aspects, the at least one inlet and the at least one outlet are higher relative to a grade level than the at least one gas-liquid interface.

[0147] In another aspect combinable with one, some, or all of the previous aspects, the at least one fan is positioned downstream of the at least one gas-liquid interface and upstream of the at least one transfer wheel, relative to the second flow direction.

[0148] In another aspect combinable with one, some, or all of the previous aspects, the first flow direction is predominately downward, and the second flow direction is predominantly upward.Attorney Docket No.: 30285-0050W01

[0149] In another aspect combinable with one, some, or all of the previous aspects, the at least one inlet includes a first inlet and a second inlet; the at least one inlet plenum includes a first inlet plenum, and a second inlet plenum, the second inlet plenum being fluidly separated from the first inlet plenum; the at least one gas-liquid interface includes a first gas-liquid interface downstream of the first inlet plenum, and a second gas-liquid interface downstream of the second inlet plenum; the at least one outlet plenum is downstream of the first and second gas-liquid interfaces, the at least one outlet air passage being fluidly connected to the first and second inlet plenums through respective first and second gas-liquid interfaces.

[0150] In another aspect combinable with one, some, or all of the previous aspects, the at least one transfer wheel includes a first transfer wheel rotatable to rotate a first transfer wheel portion through the first inlet plenum, and rotate a first capture wheel portion across a first portion of the at least one outlet plenum; and a second transfer wheel rotatable to rotate a second transfer wheel portion through the second inlet plenum, and rotate a second capture wheel portion across a second portion of the at least one outlet plenum.

[0151] In another aspect combinable with one, some, or all of the previous aspects, the at least one fan is rotatable about the fan axis to flow: the atmospheric air along the first flow direction from the first and second inlets, through the respective first and second inlet plenums, and through the first and second transfer wheel portions to form the CCh-rich gas stream; the CCh-rich gas stream along the first and second gas-liquid interfaces to form the CCh-lean gas stream; and the CCh-lean gas stream along the second flow direction through the at least one outlet plenum, through the first and second capture wheel portions, and to the at least one outlet.

[0152] In another example implementation, a method for capturing carbon dioxide (CO2) from atmospheric air includes flowing atmospheric air through at least one energy transfer wheel to form a CCh-rich gas stream resulting from the atmospheric air having received energy transferred from the at least one energy transfer wheel; flowing the CCh-rich gas stream through an inlet plenum along a first direction; flowing the CCh-rich gas stream along a gas-liquid interface; flowing a CO2 capture solution along the gas-liquid interface to absorb CO2 from the CCh-rich gas stream into the CO2 capture solution and form a CCh-lean gas stream; flowing the CCh-lean gas stream through an outlet plenum along a second direction opposite to the first direction; and flowing the CCh-lean gas stream through the at least one energy transfer wheel to form an exhaust CC -rich gas stream resulting from the CCh-lean gas stream having given energyAttorney Docket No.: 30285-0050W01 to the at least one energy transfer wheel; and rotating the at least one transfer wheel between the inlet plenum and the outlet plenum to transfer the energy between the CCh-lean gas stream and the atmospheric air, the energy including at least one of moisture or thermal energy.

[0153] In another example implementation, a gas-liquid contactor for capturing carbon dioxide (CO2) from atmospheric air includes at least one inlet; at least one outlet spaced apart from the at least one inlet; a gas-liquid interface disposed between the at least one inlet and the at least one outlet; a liquid distribution system configured to flow a CO2 capture solution along the gasliquid interface; at least one fan configured to flow atmospheric air along a flow path from the at least one inlet, along the gas-liquid interface, and to the at least one outlet, to contact the atmospheric air with the CO2 capture solution and absorb CO2 from the atmospheric air into the CO2 capture solution to form a CCh-lean gas stream flowable through the at least one outlet; and at least one energy transfer module positioned in the flow path. The at least one energy transfer module includes a first airflow circuit that includes a first airflow inlet positioned to receive the flow of atmospheric air from the at least one inlet and a first airflow outlet fluidly coupled to the first airflow inlet; a second airflow circuit fluidly separated from the first airflow circuit and including a second airflow inlet and a second airflow outlet fluidly coupled to the second airflow inlet and positioned to exhaust the CCh-lean gas stream to the at least one outlet; and a plurality of energy transfer circuits fluidly coupled to the first and second airflow circuits and configured to transfer energy between the CCh-lean gas stream and the flow of atmospheric air.

[0154] In another example implementation, a method for capturing carbon dioxide (CO2) from atmospheric air includes flowing atmospheric air into at least one inlet of a gas-liquid contactor and along a flow path; flowing the atmospheric air along a gas-liquid interface; flowing a CO2 capture solution along the gas-liquid interface to absorb CO2 from the atmospheric air into the CO2 capture solution and to form a CCh-lean gas stream; transferring energy between the CO2- lean gas stream and the atmospheric air from the at least one inlet with at least one energy transfer module positioned in the flow path; and flowing the CCh-lean gas stream through at least one outlet of the gas-liquid contactor.

[0155] In another example implementation, a direct air capture (DAC) system for capturing carbon dioxide (CO2) from atmospheric air includes at least one gas-liquid contactor. The at least one gas-liquid contactor includes at least one inlet; at least one outlet spaced apart from the at least one inlet; a gas-liquid interface disposed between the at least one inlet and the atAttorney Docket No.: 30285-0050W01 least one outlet; a liquid distribution system configured to flow a CO2 capture solution along the gas-liquid interface; at least one fan configured to flow atmospheric air along a flow path from the at least one inlet, along the gas-liquid interface, and to the at least one outlet, to contact the atmospheric air with the CO2 capture solution and absorb CO2 from the atmospheric air into the CO2 capture solution to form a CCh-lean gas stream flowable through the at least one outlet; and at least one energy transfer module positioned in the flow path. The at least one energy transfer module includes a first airflow circuit that includes a first airflow inlet positioned to receive the flow of atmospheric air from the at least one inlet and a first airflow outlet fluidly coupled to the first airflow inlet; a second airflow circuit fluidly separated from the first airflow circuit and including a second airflow inlet and a second airflow outlet fluidly coupled to the second airflow inlet and positioned to exhaust the CCh-lean gas stream to the at least one outlet; and a plurality of energy transfer circuits fluidly coupled to the first and second airflow circuits and configured to transfer energy between the CCh-lean gas stream and the flow of atmospheric air.

[0156] In another example implementation, a gas-liquid contactor for capturing carbon dioxide (CO2) from atmospheric air includes at least one inlet air passage extending from at least one inlet; at least one gas-liquid interface downstream of the at least one inlet air passage; at least one outlet air passage downstream of the at least one gas-liquid interface and extending to at least one outlet, an extent of the at least one outlet air passage being fluidly separated from the at least one inlet air passage; and a liquid distribution system configured to flow a CO2 capture solution along the at least one gas-liquid interface; at least one transfer wheel defining a wheel axis. The at least one transfer wheel is rotatable about the wheel axis to rotate a transfer wheel portion through the at least one inlet air passage and rotate a capture wheel portion through the extent of the at least one outlet air passage. The gas-liquid contactor includes at least one fan defining a fan axis, and rotatable about the fan axis to flow: atmospheric air along a first flow direction from the at least one inlet, through the at least one inlet air passage, and through the transfer wheel portion, to transfer at least one of moisture and thermal energy to the atmospheric air; atmospheric air along the at least one gas-liquid interface to contact the atmospheric air with the CO2 capture solution, and absorb CO2 from the atmospheric air into the CO2 capture solution and form a CCh-lean gas stream; and the CCh-lean gas stream along a second flow direction through the at least one outlet air passage, through the capture wheel portion, and to the at least one outlet, to capture at least oneAttorney Docket No.: 30285-0050W01 of the moisture and the thermal energy from the CCh-lean gas stream, the second flow direction being opposite to the first flow direction.

[0157] In another example implementation, a method for capturing carbon dioxide (CO2) from atmospheric air includes flowing atmospheric air through a first air passage along a first direction; flowing the atmospheric air along a gas-liquid interface; flowing a CO2 capture solution along the gas-liquid interface to absorb CO2 from the atmospheric air into the CO2 capture solution and form a CCh-lean gas stream; flowing the CCh-lean gas stream through a second air passage along a second direction opposite to the first direction; and rotating at least one transfer wheel between the first and second air passages to transfer at least one of moisture or thermal energy between the CCh-lean gas stream and the atmospheric air.

[0158] In another example implementation, a gas-liquid contactor for capturing carbon dioxide from a dilute fluid source includes at least one inlet; at least one outlet spaced apart from the at least one inlet; a gas-liquid interface positioned between the at least one inlet and the at least one outlet; a liquid distribution system configured to flow a CO2 capture solution along the gasliquid interface; at least one fan configured to flow the dilute fluid source along a flow path from the at least one inlet, along the gas-liquid interface, and to the at least one outlet, to contact the dilute fluid source with the CO2 capture solution, thereby absorbing CO2 from the dilute fluid source into the CO2 capture solution to form a CCh-lean gas stream flowable through the at least one outlet; and at least one energy transfer module positioned in the flow path. The at least one energy transfer module includes a plurality of energy transfer channels configured to transfer energy between the CCh-lean gas stream and the flow of dilute fluid source without mixing the CCh-lean gas stream and the flow of dilute fluid source.

[0159] In another example implementation, a method for capturing carbon dioxide from a dilute fluid source includes flowing a CCh-rich gas stream derived from the dilute fluid source along a gas-liquid interface in a flow path; flowing a CO2 capture solution along the gas-liquid interface to absorb CO2 from the CCh-rich gas stream into the CO2 capture solution and to form a CC -lean gas stream; and transferring energy between the dilute gas source and the CCh-lean gas stream without mixing the dilute gas source and the CCh-lean gas stream along the flow path, to produce the CCh-rich gas stream and an exhaust CCh-lean gas stream.

[0160] In another example implementation, a gas-liquid contactor for capturing carbon dioxide (CO2) from a dilute fluid source having a dilute concentration of CO2 includes at least oneAttorney Docket No.: 30285-0050W01 inlet; at least one outlet spaced apart from the at least one inlet; a gas-liquid interface positioned between the at least one inlet and the at least one outlet; a liquid distribution system configured to flow a CO2 capture solution along the gas-liquid interface; at least one fan configured to flow the dilute fluid source along a flow path from the at least one inlet, along the gas-liquid interface, and to the at least one outlet, to contact the atmospheric air with the CO2 capture solution, thereby absorbing CO2 from the dilute fluid source into the CO2 capture solution to form a CCh-lean gas stream flowable through the at least one outlet; and at least one energy transfer module positioned in the flow path. The at least one energy transfer module includes a plurality of energy transfer channels configured to transfer energy between the CCh-lean gas stream and the flow of dilute fluid source. The plurality of energy transfer channels define a first airflow circuit that includes a first airflow inlet positioned to receive the flow of dilute fluid source from the at least one inlet and a first airflow outlet fluidly coupled to the first airflow inlet; and a second airflow circuit fluidly separated from the first airflow circuit and including a second airflow inlet and a second airflow outlet fluidly coupled to the second airflow inlet and positioned to exhaust the CCh-lean gas stream to the at least one outlet.

[0161] In another example implementation, a CO2 capture system for capturing carbon dioxide (CO2) from a dilute fluid source having a dilute concentration of CO2 includes at least one gas-liquid contactor defining at least a portion of a flow path. The at least one gas-liquid contactor includes at least one inlet; at least one outlet spaced apart from the at least one inlet; a gas-liquid interface disposed between the at least one inlet and the at least one outlet; a liquid distribution system configured to flow a CO2 capture solution along the gas-liquid interface; at least one fan configured to flow the dilute fluid source along the flow path from the at least one inlet, along the gas-liquid interface, and to the at least one outlet, to contact the flow of dilute fluid source with the CO2 capture solution and absorb CO2 from the flow of dilute fluid source into the CO2 capture solution to form a CCh-lean gas stream flowable through the at least one outlet; and at least one energy transfer module. The at least one energy transfer module includes a plurality of energy transfer channels configured to transfer energy between the CCh-lean gas stream and the flow of dilute fluid source along the flow path. The plurality of energy transfer channels define a first airflow circuit that includes a first airflow inlet positioned to receive the flow of dilute fluid source and a first airflow outlet fluidly coupled to the first airflow inlet; and a second airflow circuit fluidly separated from the first airflow circuit and including a second airflow inlet and a secondAttorney Docket No.: 30285-0050W01 airflow outlet fluidly coupled to the second airflow inlet and positioned to exhaust the CCE-lean gas stream from the CO2 capture system.

[0162] In another example implementation, a method for capturing carbon dioxide (CO2) from a dilute fluid source having a dilute concentration of CO2 includes flowing the dilute fluid source into an inlet of a flow path including at least one energy transfer module; transferring energy from the at least one energy transfer module to the dilute fluid source to form a CCE-rich gas stream in the flow path; flowing the CCE-rich gas stream along a gas-liquid interface in the flow path; flowing a CO2 capture solution along the gas-liquid interface to absorb CO2 from the CCh-rich gas stream into the CO2 capture solution and to form a CCh-lean gas stream; transferring energy from the CCh-lean gas stream to the at least one energy transfer module to form an exhaust CCE-lean gas stream; and flowing the exhaust CCh-lean gas stream from the flow path.

[0163] The details of one or more example implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0164] FIG. 1 is a schematic diagram of an example implementation of a gas-liquid contactor that includes at least one energy transfer module according to the present disclosure.

[0165] FIG. 2A is a schematic diagram of an example implementation of an energy transfer module that can be implemented in a gas-liquid contactor according to the present disclosure.

[0166] FIG. 2B is a schematic diagram of another example implementation of an energy transfer module that can be implemented in a gas-liquid contactor according to the present disclosure.

[0167] FIG. 3 is a schematic diagram of an example implementation of a gas-liquid contactor that can include at least one energy transfer module according to the present disclosure.

[0168] FIGS. 4 and 5 are schematic diagrams of example implementations of a co-current gas-liquid contactor that includes at least one energy transfer module according to the present disclosure.

[0169] FIGS. 6-8 are schematic diagrams of example implementations of a gas-liquid contactor that includes at least one energy transfer module according to the present disclosure.Attorney Docket No.: 30285-0050W01

[0170] FIGS. 9 and 10 are schematic diagrams of example implementations of a gas-liquid contactor that includes at least one energy transfer belt according to the present disclosure.

[0171] FIG. 11 is a schematic illustration of a direct air capture (DAC) system for capturing carbon dioxide (CO2) from atmospheric air, the DAC system including at least one gas-liquid contactor of the present disclosure, at least one energy transfer module of the present disclosure and a regeneration system of the present disclosure.

[0172] FIG. 12 is a schematic illustration of a direct air capture (DAC) system for capturing carbon dioxide (CO2) from atmospheric air, the DAC system including at least one gas-liquid contactor of the present disclosure, at least one energy transfer module of the present disclosure and a regeneration system of the present disclosure.

[0173] FIG. 13 is a schematic illustration of a direct air capture (DAC) system for capturing carbon dioxide (CO2) from atmospheric air, the DAC system including at least one gas-liquid contactor of the present disclosure, at least one energy transfer module of the present disclosure and a regeneration system of the present disclosure.

[0174] FIG. 14 is another schematic illustration of a DAC system including at least one gas-liquid contactor of the present disclosure, at least one energy transfer module of the present disclosure and a regeneration system of the present disclosure.

[0175] FIG. 15 is another schematic illustration of a DAC system including at least one gas-liquid contactor of the present disclosure, at least one energy transfer module of the present disclosure and a solvent-based regeneration system of the present disclosure.

[0176] FIG. 16 is a schematic illustration of a DAC system including at least one gas-liquid contactor of the present disclosure, at least one energy transfer module of the present disclosure and an electrochemical regeneration system of the present disclosure.

[0177] FIG. 17 is a side view of an example contactor wall of a DAC system of the present disclosure.

[0178] FIG. 18 is a top-down view of a DAC system of the present disclosure comprising multiple contactor walls.

[0179] FIGS. 19 and 20 are flowcharts that illustrate example methods according to the present disclosure.

[0180] FIGS. 21A-21E are diagrams of chemical structures according to the present disclosure.Attorney Docket No.: 30285-0050W01

[0181] FIG. 22 is a schematic diagram of a control system (or controller) for a gas-liquid contactor according to the present disclosure.DETAILED DESCRIPTION

[0182] The present disclosure describes example implementations of gas-liquid contactors, carbon dioxide (CO2) capture systems and more particularly direct air capture (DAC) systems that include at least one gas-liquid contactor, and processes of using or operating such apparatus and systems. In example implementations, the at least one gas-liquid contactor of the present disclosure can capture CO2 from a dilute fluid source into a CO2 capture solution. The captured CO2 can then be separated from the CO2 capture solution and used or disposed of appropriately.

[0183] The dilute fluid source can include the atmosphere (e.g., ambient or atmospheric air) or another fluid source that contains dilute concentrations of CO2. Concentrations of CO2 in the atmosphere are dilute, in that they are in the range of 400-420 parts per million (“ppm”) or approximately 0.04-0.042% v / v, and less than 1% v / v. These dilute concentrations of CO2 are at least one order of magnitude lower than the concentration of CO2 in point-source emissions, such as flue gases, where point-source emissions can have concentrations of CO2 ranging from 1.5-15% v / v, or from 5-15% v / v depending on the source of emissions.

[0184] The CO2 capture system of the present disclosure includes the at least one gasliquid contactor configured to absorb CO2 from the dilute fluid source and at least one energy transfer module configured to transfer energy between the dilute fluid source and a produced CO2- lean gas stream. In example implementations, referring to FIGS. 1, 4, 6-9, 11 and 12, the dilute fluid source 1 (e.g., atmospheric air) is flowed along a flow path 8 of the CO2 capture system (e.g., a Direct Air Capture (DAC) system 800, 900, 1200, 2000, 3000).

[0185] FIG. 1 is a schematic diagram of an example implementation of a gas-liquid contactor 10 that includes at least one energy transfer module 20 according to the present disclosure. The dilute fluid source 1 (that has a particular concentration of carbon dioxide) is flowed into the at least one energy transfer module 20 to recover energy from the dilute fluid source 1 and produce a CO2-rich gas stream 5. The CCh-rich gas stream 5 thus has a different energy level than the dilute fluid source 1 being flowed to the at least one energy transfer module 20. However, the CCh-rich gas stream 5 has the same CO2 concentration as the dilute fluid source 1 since the at least one energy transfer module 20 is configured to transfer energy to or from a gasAttorney Docket No.: 30285-0050W01 stream without affecting a CO2 concentration thereof. The CCh-rich gas stream 5 is further flowed along the flow path 8 to at least one packing section 12a, 12b, 12c of the gas-liquid contactor 10 to contact a CO2 capture solution that absorbs at least a portion of the CO2 from the CCh-rich gas stream 5 to produce a CO2 lean gas stream 7. Some or all of the CO2 in the CCE-rich gas stream 5 is removed by absorption into the CO2 capture solution and further reaction with at least one CO2 capture species from the CO2 capture solution, thereby forming the CCh-lean gas stream 7 (or, CO2-IOW air). In operating to treat the CCh-rich gas stream 5 (such as atmospheric air) in this manner, the gas-liquid contactor 10 can sometimes be referred to herein as an “air contactor” because it facilitates absorption of CO2 from the CCh-rich gas stream 5 into the CO2 capture solution. In contrast to water cooling towers which function primarily to transfer heat between water and atmospheric air, the gas-liquid contactor 10 functions primarily to achieve mass transfer of CO2 from the CCh-rich gas stream 5 (such as atmospheric air) to the CO2 capture solution. In operating in this manner, the gas-liquid contactor 10 can be used as part of a CO2 capture system, such as DAC systems 800, 900, 1200, 2000, 3000, described in greater detail below in reference to FIGS. 11-16.

[0186] Still referring to FIG. 1, the CO2 lean gas stream 7 is further flowed back into the at least one energy transfer module 20 to recover energy from the at least one energy transfer module 20 and produce an output gas stream 3 that has a lower concentration of carbon dioxide than the dilute fluid source 1 and the CCh-rich gas stream 5. The output gas stream 3 is exhausted from the gas-liquid contactor 10, such as into the atmosphere.

[0187] In example implementations, the gas-liquid contactor 10 includes the at least one energy transfer module 20 that is positioned in the gas-liquid contactor 10 to receive both fluid streams (the dilute fluid source 1 and the CO2 lean gas stream 7) therethrough. Energy is transferred between the dilute fluid source 1 and the CO2 lean gas stream 7 based on, for example, one or more psychrometric characteristics of the dilute fluid source 1 and / or the CO2 lean gas stream 7, one or more flow characteristics of the dilute fluid source 1 and / or the CO2 lean gas stream 7, or other operating parameters of the gas-liquid contactor 10.

[0188] By implementing one or more energy transfer modules in example implementations of gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 or CO2 capture systems, such as DAC systems 800, 900, 1200, 2000, 3000, one or more advantages can be achieved. For example, in example implementations, waste heat energy that would otherwise be lost to theAttorney Docket No.: 30285-0050W01 atmosphere can be recycled to more efficiently capture the carbon dioxide with the CO2 capture solution. Further, in example implementations, moisture that would otherwise be lost to the atmosphere can be transferred between the dilute fluid source and the output gas stream. Such moisture recapture can reduce an amount of make-up water (or other liquid) that may be required for gas-liquid contactors. Thus, operating efficiencies of a gas-liquid contactor in a DAC system can be optimized or improved.

[0189] Referring to FIG.1, in example implementations, the gas-liquid contactor 10 operates to capture CO2 from the dilute fluid source 1 as defined herein, being for example ambient or atmospheric air. Certain components and details of the gas-liquid contactor 10 are not shown in FIG. 1 but are described and shown elsewhere in the present disclosure (such as in FIG. 3), and such components can be implemented in the gas-liquid contactor 10 of FIG. 1, and of the gasliquid contactors 10 of the present disclosure.

[0190] In the example implementation of FIG. 1, the gas-liquid contactor 10 includes a housing 2 that, among other functions, provides structural support and other structural integrity functionality for the gas-liquid contactor 10. The housing 2 provides for at least one inlet 4 and at least one outlet 6. The at least one inlet 4 and the at least one outlet 6 are part of, and at least partially define, the flow path 8 that extends from the at least one inlet 4, downward through the housing 2 (away from the at least one outlet 6) and then upward through the housing 2 toward and through the at least one outlet 6. The gas-liquid contactor 10 further includes the at least one packing section 12a, 12b, 12c that is structurally supported by the housing 2 and positioned across the flow path 8 to allow the dilute gas source 1 to flow from the at least one inlet 4 and through the at least one packing section 12a, 12b, 12c along the flow path 8. The at least one packing section 12a, 12b, 12c provides a gas-liquid interface where the flowing dilute gas source 1 can contact the CO2 capture solution.

[0191] As shown in the example implementation of FIG. 1, in addition to the at least one inlet 4 and the at least one outlet 6, the flow path 8 is defined by, or includes, at least one inlet plenum 9 or inlet air passage extending from the inlet 4 and to the at least one packing section 12a, 12b, 12c. The at least one inlet plenum of the present disclosure (e.g., the inlet plenum 9 of FIG. 1) defines a portion of the flow path being upstream of a first-encountered gas-liquid interface (e.g., packing section 12b in FIG. 1 when present, or packing section 12a of FIG. 1). The flow path 8 is further defined by an outlet plenum 13 or outlet air passage extending from the at leastAttorney Docket No.: 30285-0050W01 one packing section 12a, 12b, 12c to the at least one outlet 6. The outlet plenum of the present disclosure (e.g., the outlet plenum 13 of FIG. 1) defines a portion of the flow path being downstream of a last-encountered gas-liquid interface (e.g., packing section 12c in FIG. 1 when present, or packing section 12a of FIG. 1).

[0192] Referring to FIG.l, for example, a duct 14 is formed in the housing 2 to, with the housing 2, define the flow path 8 and its different sections including the at least one inlet 4, the inlet plenum 9, the outlet plenum 13 and the at least one outlet 6. Duct 14, in example aspects, forms a conduit through which the CO2 rich gas stream 5 and the CO2 lean gas stream 7 flow in opposing directions. Duct 14, in the example implementations, fluidly separates the flow of the CO2 rich gas stream 5 from the flow of the CO2 lean gas stream 7, such that the CO2 rich gas stream 5 is forced through the one or more gas-liquid interfaces being provided by the at least one packing section 12a, 12b, 12c (as described later) to produce the CO2 lean gas stream 7, prior to being output from the gas-liquid contactor 10 as, e.g., exhaust air 3. Thus, at least a portion of duct 14 defines the inlet plenum 9 upstream of the at least one packing section 12a, 12b, 12c (e.g., between the inlet 4 and a first packing section 12b), and the outlet plenum 13 downstream of the at least one packing section 12a, 12b, 12c (e.g., between a third packing section 12c and the outlet 6). At least a portion of the duct 14 defines a dividing wall 19 that separates the inlet plenum 9 and the outlet plenum 13. The dividing wall 19 extends to an upper portion of the at least one packing section 12a, such that the inlet plenum 9 and outlet plenum 13 can be in fluid communication through the at least one packing section 12a. The duct 14 of FIG. 1 has a vertical orientation.

[0193] The gas-liquid contactor 10 also includes at least one fan 11 that is positioned in and coupled to the housing 2. The at least one fan 11 can be operated to flow and treat the dilute gas source 1 along the flow path 8 through the at least one inlet 4, the inlet plenum 9, the at least one packing section 12a, 12b, 12c, the outlet plenum 13, and out of the at least one outlet 6 during operation of the gas-liquid contactor 10. For example, the at least one fan 11 is positioned in fluid communication with the outlet plenum 13 so that the CCh-lean gas stream 7 is flowed from the at least one packing section 12a, 12b, 12c to the at least one outlet 6 through the at least one energy transfer module 20. Although illustrated in FIG. 1 as being downstream of the at least one packing section 12a and upstream of the at least one energy transfer module 20, the at least one fan 11 can be positioned, for example, downstream of the at least one energy transfer module 20, or upstreamAttorney Docket No.: 30285-0050W01 of the counter-flow packing section 12c (if used) to, for instance, improve fan efficiency (by changing from an induced-draft fan to forced-draft fan arrangements relative to, for example, the energy transfer modules 20 or packing section(s) 12a, 12b, or 12c). In addition, in example aspects, fan 11 can be multiple fans, either positioned in parallel in flow path 8 or in series in flow path 8.

[0194] As shown in the example implementation of FIG. 1, at least one gas-liquid interface 12a, 12b, 12c is positioned in the housing 2 and within the flow path 8. In example implementations (as described in more detail with reference to FIG. 3), the at least one gas-liquid interface 12a, 12b, 12c is provided by at least one corresponding packing section 12a, 12b, 12c that comprises one or more packings or packing materials through which the CO2 capture solution can be flowed to contact the CO2 rich gas stream 5 that is flowed through the at least one packing section 12a, 12b, 12c by the fan 11. Within each packing section 12a, 12b, 12c forming a gasliquid interface, the CO2 capture solution (e g., liquid sorbent) contacts the CO2 rich gas stream 5 and captures at least a portion of CO2 contained within the CChrich gas stream 5, thereby reducing a concentration of CO2 within the flowing gas stream (and increasing an amount or concentration of carbon within the CO2 capture solution) to form the CO2 lean gas stream 7. Once the CO2 rich gas stream 5 passes through the at least one packing section 12a, 12b, 12c and is relieved of at least some of its CO2, the resulting CO2-lean airstream 7 is flowed from the at least packing section 12a, 12b, 12c toward the outlet 6 through the outlet plenum 13.

[0195] Additional or alternative positions of the at least one gas-liquid interface 12a, 12b, 12c are also shown in FIG. 1. For example, the at least one gas-liquid interface 12a, 12b, 12c can include a cross-flow gas-liquid interface 12a that is positioned to facilitate a cross-flow gas-liquid contactor arrangement, where the CO2 capture solution flows downwardly through the cross-flow gas-liquid interface 12a and contacts the CO2 rich gas stream 5 flowing along a predominantly horizontal position through the cross-flow gas-liquid interfaces 12a. The at least one gas-liquid interface 12a comprises an inlet portion disposed on one side of the dividing wall 19 and in fluid communication with the at least one inlet plenum 9, and an outlet portion disposed on the other side of the dividing wall 19 and in fluid communication with the at least one outlet plenum 13.

[0196] For example, the at least one gas-liquid interface 12a, 12b, 12c can additionally or alternatively include a co-current gas-liquid interface 12b that is positioned along the flow path 8 to facilitate a co-current gas-liquid contactor arrangement, where the CO2 capture solution and theAttorney Docket No.: 30285-0050W01C02rich gas stream 5 both flow downwardly through the co-current gas-liquid interface 12b. For example, the at least one gas-liquid interface 12a, 12b, 12c can additionally or alternatively include a counter-flow gas-liquid interface 12c that is positioned along the flow path 8 to facilitate a counter-flow gas-liquid contactor arrangement, where the CO2 capture solution flows downwardly through the counter-flow gas-liquid interface 12c while the CO2 rich gas stream 5 flows upwardly through the counter-current gas-liquid interface 12c. Thus, the example implementation of the gas-liquid contactor 10 (and other gas-liquid contactors according to the present disclosure) can be implemented as cross-flow, co-current, or counter-flow arrangements, or any combination of the preceding.

[0197] As further shown in the example implementation of FIG. 1 the gas-liquid contactor 10 includes a basin 21 (such as a bottom basin). The basin 21, as shown, collects a CCh-rich capture solution 23 that flows into the basin 21 from the at least one packing section 12a, 12b, or 12c, resulting from the CO2 capture solution having absorbed CO2 from the CO2 rich gas stream 5. At least a portion of the CCh-rich capture solution 23 can be redistributed back to the at least one packing section 12a, 12b, or 12c to further absorb CO2 from the CO2 rich gas stream 5. The bottom basin 21 can be compatible with a containment structure and prevent loss of various CO2 capture solutions 23, some of which might have corrosive, caustic or high pH properties. For example, the bottom basin 21 is lined or coated with one or more materials that are resistant to caustic induced corrosion or degradation. FIG. 1 shows an implementation where a liquid collection device of the gas-liquid contactor 10 is or includes a bottom basin 21. In FIG. 1, one or more of the liquid collection devices 109 include, or are in the form of, basins. Other implementations of the gas-liquid contactor can include a liquid collection device being or including a reservoir, a bed, a sheet, a culvert, a container, a receptacle, a network of pressurized pipes with openings or spray nozzles, or any other device capable of retaining liquid.

[0198] In example implementations, the at least one energy transfer module 20 is positioned upstream of the at least one fan 11 of the gas-liquid air contactor 10. In example implementations, the at least one energy transfer module 20 is part of the gas-liquid contactor 10. In other example implementations, as described in greater detail below, the at least one energy transfer module 20 is separate from the gas-liquid contactor 10. As shown in the example implementation of the gas-liquid contactor 10 of FIG. 1, the at least one energy transfer module 20 is positioned in the housing 2 of the gas-liquid contactor 10 and, more particularly, within theAttorney Docket No.: 30285-0050W01 flow path 8. In this example, the at least one energy transfer module includes two energy transfer modules 20 positioned in the gas-liquid contactor 10.

[0199] The gas-liquid contactor 10 of FIG. 1 can be considered a dual cell gas-liquid contactor 10 because the CO2 rich gas stream 5 travels through two separate inlet plenums 9 in fluid communication with separate packing sections 12a, 12b serving as gas-liquid interfaces. The dilute fluid source 1 (e.g., atmospheric air) entering via one of the inlets 4 flows through one energy transfer module 20 and further flows as CO2 rich gas stream 5 through at least one gas-liquid interface 12b, 12a, or 12c. Another stream of the dilute fluid source 1 entering via the other and second inlet 4 flows through a separate and second energy transfer module 20 and further flows as CO2 rich gas stream 5 through one or more separate gas-liquid interfaces 12b, 12a, 12c.

[0200] However, in alternative implementations, the gas-liquid contactor 10 can be a single cell gas-liquid contactor, where the dilute fluid source 1, e.g., atmospheric air, entering via the at least one inlet 4 flows through a single energy transfer module 20, a single inlet plenum, at least one packing section 12a, 12b, 12c, and back to the single energy transfer module 20. Generally, and regardless of the number of cells, the at least one inlet 4 and the at least one outlet 6 are fluidly separated from each other along their parallel portions and only communicate indirectly via the at least one gas-liquid interface of the gas-liquid contactor 10 (such as through the at least one packing section 12a, 12b, or 12c).

[0201] Referring to FIG. 1, as shown in this example implementation, each energy transfer module 20 (of two energy transfer modules 20 being illustrated in FIG. 1) includes a first airflow circuit 22 being in fluid communication with the inlet plenum 9 and a second airflow circuit 24 being in fluid communication with the outlet plenum 13. The first airflow circuit 22 includes an inlet 26 and an outlet 28. The second airflow circuit 24 includes an inlet 30 and an outlet 32. Generally, first airflow circuit 22 and second airflow circuit 24 are fluidly decoupled from each other, such that no gas (e.g., air) flows between the first airflow circuit 22 and the second airflow circuit 24. However, first airflow circuit 22 and second airflow circuit 24 (as explained in more detail herein) are in energy communication with each other, such that energy can be transferred between airflows that flow through the respective first airflow circuit 22 and second airflow circuit 24. In example implementations, the energy transferred between the two airflows is at least one of thermal energy and / or chemical energy. In the present disclosure, energy can be transferred in one, some, or all of the example forms described herein.Attorney Docket No.: 30285-0050W01

[0202] As an example, thermal energy can include (all, substantially, or primarily) sensible heat that causes an increase of temperature (e.g., dry bulb temperature) in one airflow flowed through the at least one energy transfer module 20 with a corresponding decrease of temperature (e.g., dry bulb temperature) in another airflow flowed through the at least one energy transfer module 20.

[0203] As another example, thermal energy can include (all, substantially, or primarily) latent heat that causes a change of phase (e.g., evaporation or condensation of water in the airstreams leading to a decrease or increase of the wet bulb temperature) in airflows flowed through the at least one energy transfer module 20. In example implementations, energy can include at least one of sensible heat and latent heat, for example both sensible heat and latent heat, transferred from one airflow to another airflow through the at least one energy transfer module 20.

[0204] As another example, thermal energy can include (all, substantially, or primarily) enthalpy that causes an increase of temperature (e.g., dry bulb temperature, wet bulb temperature, or both) in one airflow flowed through the at least one energy transfer module 20 with a corresponding decrease of temperature (e.g., dry bulb temperature, wet bulb temperature, or both) in another airflow flowed through the at least one energy transfer module 20. In example implementations, energy can include a combination of two or more of sensible heat, latent heat, and enthalpy transferred from one airflow to another airflow through the at least one energy transfer module 20.

[0205] As another example, energy can include (all, substantially, or primarily) chemical energy that is transferred between airflows by the transfer of mass (e.g., moisture) from one airflow to another airflow. A transfer of chemical energy may include no or an insignificant amount of thermal energy (e.g., sensible heat, latent heat, enthalpy, or a combination thereof). The transfer of chemical energy can be caused by a transfer of energy inherent in mass that is transferred (e.g., as moisture) from one airflow to another airflow through the at least one energy transfer module 20.

[0206] Energy definitions provided with reference to the at least one energy transfer module 20 apply mutatis mutandis to other energy transfer modules of the present disclosure.

[0207] FIGS. 2A and 2B show example energy transfer modules 200, 250 that can be implemented in a gas-liquid contactor according to the present disclosure. FIG. 2A is a schematic diagram of an example implementation of the at least one energy transfer module 20 being anAttorney Docket No.: 30285-0050W01 energy transfer wheel 200 that can be implemented in a gas-liquid contactor according to the present disclosure. FIG. 2B is a schematic diagram of another example implementation of the at least one energy transfer module being an energy recovery ventilator 250 that can be implemented in a gas-liquid contactor according to the present disclosure. FIGS. 9 and 10 are schematic illustrations of another example implementation of the at least one energy transfer module 20 that can be, or take the form of, an energy transfer belt 320 that is implemented in a gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 according to the present disclosure. In example implementations, the at least one energy transfer module 20, 200, 250, 720 can include multiple energy transfer modules 20, 200, 250, 320, 402, 440, 502, 540, 602, 640, 642 being coaxial and / or stacked on one another to transfer at least one of thermal energy and / or chemical energy between airflows as further described below.

[0208] Referring to FIG. 2A, the energy transfer wheel 200 can be implemented as a thermal energy transfer wheel (e.g., that transfers sensible heat, latent heat, enthalpy, or a combination thereof) or a chemical energy transfer wheel being also referred to as a desiccant wheel when transferring chemical energy between airflows via moisture. In the example implementation, energy transfer wheel 200 includes a housing 206 that supports, couples together, or is formed from annular sheets 202 (e.g., made of corrugated metal, sheet metal, or other energy transfer material having a sufficient heat transfer coefficient and / or other suitable property) that circumscribe a radial center 230 and define annular airflow channels 204 therebetween.

[0209] In example implementations, a wheel axis 242 that extends through the radial center 230 of the energy transfer wheel 200 is generally vertical with respect to gravity but can be oriented offset from vertical according to the gas-liquid contactor in which the energy transfer wheel 200 is mounted. A fluid barrier 210 comprises a planar surface that intersects the radial center 230 as shown and generally divides the energy transfer wheel 200 into a first hemisphere 205a (including or defining the first airflow circuit 22 or the second airflow circuit 24) and a second hemisphere 205b (including or defining the other of the first airflow circuit 22 or the second airflow circuit 24). In example aspects, the fluid barrier 210 can be part of a housing of a gas-liquid contactor (such as housing 2 of gas-liquid contactor 10) or, as an example, part of or formed by a plenum of a gas-liquid contactor (such as duct 14 of the gas-liquid contactor 10).

[0210] In example aspects, the wheel axis 242 is aligned (e.g., parallel and centered on) with the fluid barrier 210 that separates the first airflow circuit 207 of a gas-liquid contactor being,Attorney Docket No.: 30285-0050W01 for example, an inlet airflow circuit, from the second airflow circuit 208 being, for example, an outlet airflow circuit of the gas-liquid contactor. Thus, in the example gas-liquid contactor 10 (and others according to the present disclosure), the fluid barrier 210 can be duct 14 such that the wheel axis 242 can be aligned with duct 14.

[0211] In example aspects, the annular airflow channels 204 of the energy transfer wheel 200 can be larger (in dimension between annular sheets 202) as compared to other energy transfer wheels (such as wheels for HVAC applications). For example, in example aspects, the annular airflow channels 204 may define a gap greater than 3 mm, and up to 26 mm. By increasing this dimension (labeled “G” in FIG. 2A), an airflow pressure drop through the annular airflow channels 204 can be reduced, thereby increasing, e.g., fan efficiency of a gas-liquid contactor.

[0212] Optionally, at least some of the annular sheets 202 can include a desiccant coating 217 distributed onto at least a portion of an inner surface of the annular sheets 202. For example, in example aspects, the energy transfer wheel 200 operates as a desiccant wheel that transfers chemical energy (e.g., moisture) and, possibly, some amount of thermal energy as well, between the two input airflows 214, 218 (e.g., the dilute fluid source 1 and the CO2-lean gas stream 7) that pass through the energy transfer wheel 200 along the inlet airflow circuit 207 or the outlet airflow circuit 208 as it rotates about the wheel axis 242. The desiccant coating 217 therefore absorbs moisture from one of the input airflows 214 or 218, e.g., the airflow with the greater relative humidity, as that airflow passes through one of the hemispheres 205a or 205b. The desiccant coating 217 then releases the absorbed moisture into the other of the input airflows 214 or 218, e.g., the airflow with the lower relative humidity, flowing through the other of the hemispheres 205a or 205b during rotation of the energy transfer wheel 200.

[0213] Movement of the at least one energy transfer module, such as the energy transfer wheel 200, is performed while preventing any mixing of incoming gas streams, such as airflows 214, 218 or output gas streams, such as airflows 216, 220.

[0214] Still referring to FIG. 2A, in operation, a motor 240 operates to rotate a shaft 231 about the radial center 230 of the housing 206 to rotate the annular sheets 202 about the wheel axis 242 along direction R. In this example, two input airflows 214 and 218 enter the annular airflow channels 204 and exit the annular airflow channels 204 as output airflows 220 and 216, respectively. As the airflows 214 and 218 enter the annular airflow channels 204, there is no or insignificant airflow transfer between the annular airflow channels 204 that rotate through the firstAttorney Docket No.: 30285-0050W01 hemisphere 205a and the annular airflow channels 204 that rotate through the second hemisphere 205b due to the fluid barrier 210. However, as the airflows 214 and 218 enter the annular airflow channels 204, there is energy transfer between the input airflow 214 and the input airflow 218 within the annular airflow circuits channels 204 that rotate through the first hemisphere 205a and the annular airflow channels 204 that rotate through the second hemisphere 205b.

[0215] Due to the rotation of the annular sheets 202 about the wheel axis 242, at any time during operation, about half of the circumferential dimension of the annular airflow channels 204 (a “transfer” wheel portion) receives an airflow (e.g., dilute fluid source 1) that can be considered as a “transfer” airflow in that energy is transferred from that airflow into another, fluidly separate airflow (e.g., CCh-lean airstream 7). At the same time, the other half of the circumferential dimension of the annular airflow channels 204 (a “capture” wheel portion) receives an airflow (e.g., CCh-lean airstream 7) that can be considered as a “capture” airflow in that energy is captured into that airflow from the transfer airflow (e.g., dilute fluid source 1). Due to the rotation of the wheel 200, however, each one of the hemisphere 205a and hemisphere 205b gradually convert from the transfer portion to the capture portion and vice versa. Accordingly, the energy transfer wheel 200 of the present disclosure (and other transfer wheels that can be used in the gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000), as a rotating body, relies on the rotation to achieve a desired energy transfer between two airstreams, such as a CCh-lean airstream and a CCh-rich airstream.

[0216] In the example implementation of the energy transfer wheel 200 of FIG. 2A, a counter-flow arrangement is shown, in which input airflows 214 and 218 are flowed into the annular airflow channels 204 in opposite directions (and output airflows 216 and 220 exit in opposite directions), where the flow directions are defined parallel to the wheel axis 242. In alternative implementations, a parallel flow arrangement of energy transfer wheel 200 can be implemented. For example, in a parallel flow arrangement, input airflows 214 and 218 are flowed into the annular airflow channels 204 in the same direction (and output airflows 216 and 220 exit in the same direction). An amount of energy transferred between the illustrated airflows can be affected by a counter-flow or parallel flow arrangement.

[0217] Turning specifically to FIG. 2B, the energy recovery ventilator 250 includes a housing 252 that includes or encloses an energy recovery core 262 mounted therein. The energy recovery core 262 is made of an energy transfer material which, generally, comprises, e.g., a fiberAttorney Docket No.: 30285-0050W01 or a polymer membrane, layered in a cross-flow corrugated structure that facilitates a transfer of energy between two input airflows that enter the housing 252. The cross-flow corrugated structure defines a plurality of adjacent energy transfer channels in the energy recovery core 262 allowing energy transfer between a first input airflow 264 and a second input airflow 268, without any mixing of such airflows 264, 268. For example, as shown, the first input airflow 264 enters a first inlet 254, is flowed through the energy recovery core 262, and exits through a first outlet 260 as first output airflow 270 (having undergone a change due to an energy transfer). The second input airflow 268 enters a second inlet 258, is flowed through the energy recovery core 262, and exits through a second outlet 256 as second output airflow 266 (having undergone a change due to an energy transfer). Thus, during operation of the energy recovery ventilator 250, energy is transferred between the first and second input airflows 264 and 268 within the energy recovery core 262 such that air flowing in the first output airflow 270 has different psychrometric (and / or other) characteristics than the air flowing in the first input airflow 264, and the air flowing in the second output airflow 266 has different psychrometric (and / or other) characteristics than the air flowing in the second input airflow 268. There is no fluid mixing, however, of the two airflows within the energy recovery core 262.

[0218] In example aspects, a desiccant coating (similar to desiccant coating 217) can be applied to some or all of the energy recovery core 262. As with the example of the desiccant coating 217, a desiccant coating applied to the energy recovery core 262 can absorb moisture from one of the first or second input airflows 264 or 268, e g., the airflow with the greater relative humidity, as that airflow passes through the energy recovery core 262. The desiccant coating then releases the absorbed moisture into the other of the first or second input airflows 264 or 268, e.g., the airflow with the lower relative humidity, as that airflow passes through the energy recovery core 262.

[0219] Returning to FIG. 1, for example, in operation of the gas-liquid contactor 10, the at least one fan 11 draw the dilute fluid source 1 into the at least one inlet 4 of the flow path 8 and through the first airflow circuit 22. Simultaneously, the at least one fan 11 flows the CCh-lean airstream 7 from the at least one packing section 12a, 12b, 12c through the second airflow circuit 24. Energy transfer occurs in the at least one energy transfer module 20 between the dilute fluid source 1 and the CCh-lean airstream 7 such that the resulting CCh-rich airstream 5 leaves the first airflow circuit 22 (through outlet 28) of each energy transfer module 20 with differentAttorney Docket No.: 30285-0050W01 psychrometric (and / or other) characteristics than the dilute fluid source 1, and exhaust air 3 leaves the second airflow circuit 24 (through outlet 32) of each energy transfer module 20 with different psychrometric (and / or other) characteristics than the CCh-lean airstream 7.

[0220] The example gas-liquid contactor 10 of FIG 1, in example aspects, can be operated in any environment but, in particular, a relatively dry environment in which the at least one energy transfer module 20 is implemented as enthalpy transfer modules (e.g., enthalpy transfer wheels, enthalpy transfer ventilators, or enthalpy transfer belt). In this example, the dilute fluid source 1 has a lower relative humidity than the CCh-lean airstream 7 (e.g., is drier than the CCh-lean airstream 7). Thus, as the dilute fluid source 1 passes through the first airflow circuit 22 and the CCh-lean airstream 7 passes through the second airflow circuit 24, energy in the form of enthalpy (e.g., moisture and / or heat of absorption of the moisture onto the energy transfer module 20) is transferred from the CCh-lean airstream 7 to the dilute fluid source 1.

[0221] The CCh-rich airstream 5 leaving the first airflow circuit 22 (through outlet 28), therefore, has a greater relative humidity and / or temperature (e.g., dry bulb, wet bulb, or both) than the dilute fluid source 1. Also, the exhaust air 3 leaving the second airflow circuit 24 (through outlet 32), therefore, has a lower relative humidity and / or temperature (e.g., dry bulb, wet bulb, or both) than the CCh-lean airstream 7. In example aspects, relative humidity values of the dilute fluid source 1 and the exhaust air 3 are within about 3% of each other due to operation of the energy transfer modules 20. Thus, about 85-90% of moisture in the CCh-lean airstream 7 is being transferred to the dilute fluid source 1 through operation of the at least one energy transfer module 20.

[0222] In example aspects, this example operation of the gas-liquid contactors 10 can provide for a water conservation mode of operation, in which water (in the form of transferred moisture) is preserved within the CO2 capture process without having to add external make-up or additional water. For example, in example implementations of operation of the gas-liquid contactor 10 without the energy transfer modules 20 and depending on characteristics of the dilute fluid source 1 (e.g., temperature, relative humidity, etc.), water may flow out of the gas-liquid contactor 10 with the exhaust air 3 and be irrecoverable. In such implementations, moisture in a liquid capture solution (e.g., such as a CO2 capture solution 114 described below) that flows along the at least one gas-liquid interface 12a, 12b, 12c is vaporized as a result of evaporative cooling which occurs during gas-liquid contact, such that water vapour is entrained in the exhaust air 3Attorney Docket No.: 30285-0050W01 that flows from the gas-liquid contactor 10 and is lost to the surrounding environment. After a period of time, it may be necessary to add water to the gas-liquid contactor 10 to make-up for these evaporative losses, and such make-up water may be costly or difficult to source. The water conservation mode of operation that is possible with the energy transfer modules 20 of the gasliquid contactor 10 allows for some, or nearly all, of the moisture in the exhaust air 3 that results from evaporative cooling to be transferred into the inlet stream of dilute fluid source 1. This provides water savings for a DAC system 800, 900, 1200, 2000, 3000 (see, for example, FIGS. 11-16), and may also warm up the bulk fluid temperature of the CCh-rich airstream 5 flowing in the inlet plenum 9 before gas-liquid contact through the at least one packing section 12a, 12b, 12c, which may enhance CO2 capture kinetics and efficiency.

[0223] Referring to FIG. 3, the present disclosure describes systems and methods for capturing carbon dioxide (CO2) with a gas-liquid contactor 100, from the atmosphere (e.g., ambient or atmospheric air) or from another dilute fluid source that contains dilute concentrations of CO2. The gas-liquid contactor 100 can include one or more energy transfer modules of the present disclosure, which can be implemented according to, e.g., the descriptions of gas-liquid contactors 10, 300, 400, 500, 600, 2100, 3100, 5000 and in accordance with the present disclosure. Further, one or more components of the gas-liquid contactor 100 that are not shown in FIGS. 1, 4, 5, or 6, can be implemented as appropriate in the gas-liquid contactors 10, 300, 400, 500, 600, 2100, 3100, 5000.

[0224] In example implementations, the gas-liquid contactor 100 is operated to capture the dilute CO2 present in the dilute fluid source 1, such as ambient air, by ingesting the dilute fluid source 1 and forming a flow of CCh-rich airstream 101, and by treating the CCh-rich airstream 101 so as to transfer CO2 present therein to a CO2 capture solution 114 (e.g., a CO2 sorbent of a gasliquid interface) via absorption. Some or all of the CO2 in the CCh-rich airstream 101 is removed, and the treated CCh-rich air 101 is then discharged by the gas-liquid contactor 100 as a flow of CCh-lean airstream 105 (or, CO2-IOW air, sometimes referred to herein as the exhaust air 3 of FIG. 1). In operating to treat atmospheric air in this manner, the gas-liquid contactor 100 may sometimes be referred to herein as an “air contactor” because it facilitates absorption of CO2 from the atmospheric air into the CO2 capture solution 114. In contrast to water cooling towers which function primarily to transfer heat between water and atmospheric air, the gas-liquid contactor 100 functions primarily to achieve mass transfer of CO2 from the atmospheric air to the CO2 captureAttorney Docket No.: 30285-0050W01 solution 114. In operating in this manner, the gas-liquid contactor 100 may be used as part of a direct air capture (DAC) system 1200, described in greater detail below in reference to FIG. 7.

[0225] In example implementations, and referring to FIG. 3, the CO2 capture solution 114 is a caustic solution. In example implementations, the CO2 capture solution 114 has a pH of 10 or higher. In example implementations, the CO2 capture solution 114 has a pH of approximately 14. Non-limiting examples of the CO2 capture solution 114 include aqueous solutions of an alkali metal sorbent, such as an alkali metal hydroxide (e.g., including KOH, NaOH, LiOH or a combination thereof as the at least one CO2 capture species), aqueous amine solutions, aqueous amino acid salt solutions, non-aqueous amine solutions, non-aqueous organic liquids / solutions (e.g., dimethyl sulfoxide or DMSO), aqueous guanidinium solutions, aqueous aminosilicone solutions, aqueous amidine solutions, non-aqueous phosphazene solutions, aqueous amines slurries with MOF, aqueous slurries with amine polymers, aqueous carbonate and / or bicarbonate solutions, aqueous phenoxi de / phenoxi de salt solutions, ionic liquids, non-aqueous solvents, or any combinations thereof. In example implementations, the solvent of the CO2 capture solution 114 has a higher vapour pressure than that of the CO2 capture species to facilitate regeneration of the CO2 capture solution 114. In example implementations, the CO2 capture solution 114 can include a guanidine-based capture species as the at least one CO2 capture species, for example an aminoguanidine or an iminoguanidine. Non-limiting examples of the guanidine-based capture species of the CCh-capture solution 114 include bis-iminoguanidines. Examples of bis- iminoguanidines include 2,5-furan-bis(iminoguanidine) (FuBIG) whose chemical structure is shown in FIG. 21 A.

[0226] Non-limiting examples of amine-based capture species of the CCh-capture solution 114 include an imine, an amidine, an amine, a hindered or non-hindered amine group having alkanolamine and alcoholic hydroxyl, carbonyl or carboxyl groups, or a combination thereof. Non-limiting examples of amines have at least one amino group (monoamine), at least two amino groups (diamine), at least three amino groups (triamine) or more amino groups (multiamine).

[0227] In example implementations, the CO2 capture solution 114 can include a diamine as the at least one CO2 capture species, for example a diamine with an aminocyclic compound group. For example, the at least one CO2 capture species includes cyclopentane- 1,3 -diamine (being functionalized or not). For example, the aminocyclic compound group can be an aminocyclohexyl group. For example, the at least one CO2 capture species includes a diamineAttorney Docket No.: 30285-0050W01 including a cyclic compound being functionalized by a hydrocarbon chain (R). For example, the at least one CO2 capture species includes a diamine including a cyclic compound being functionalized by a functional group (X). For example, the at least one CO2 capture species includes a diamine including a cyclic compound being functionalized by two amino groups in a first and third position of the cyclic compound, and by a hydrocarbon chain (R) and / or a functional group (X) at another position of the cyclic compound (e.g., cyclohexane-l,3-diamine-5 R X). The hydrocarbon chain R can be straight or branched, with or without rings, and can vary in length. The functional group X can functionalize the cyclic compound and / or the hydrocarbon chain R. The functional group X can be, without being limited to, alcohol, amine, amide, carboxylic acid, ester, ether, halogen, metal, or any combinations thereof. The hydrocarbon chain R can be, without being limited to, butane, pentane, hexane, or cycloalkane. Both the hydrocarbon chain R and the functional group X can exist independently or together at a same position of the cyclic compound (e.g., fifth position of a cyclohexane ring), or at other positions of the cyclic compound. For example, the at least one CO2 capture species includes cyclohexane- 1,3 -diamine. For example, the at least one CO2 capture species includes a cyclohexane- 1,3 -diamine-5 R X, where R is butane and X is an amino group, such as cyclohexane-l,3-diamine-5-normal-butane-amine. For example, the at least one CO2 capture species includes a cyclohexane- 1,3 -diamine-5 R X, where R is hexane and X is absent, such as cyclohexane-l,3-diamine-5-normal-hexane. For example, the at least one CO2 capture species includes 3-(aminomethyl)-3,5,5-trimethylcyclohexylamine, also referred to as isophorone diamine or IPDA whose chemical structure is shown in FIG. 2 IB.

[0228] Examples of the alkanolamine include monoethanolamine (MEA), diethanolamine, triethanolamine, methyldiethanolamine, diisopropanolamine, and diglycolamine. An example of the hindered amine having alcoholic hydroxyl includes 2-amino-2-methyl-l -propanol (AMP) whose chemical structure is shown in FIG. 21C. Another example of the hindered amine having alcoholic hydroxyl includes 2-(ethylamino)-ethanol (EAE) whose chemical structure is shown in FIG. 2 ID. Another example of the hindered amine having alcoholic hydroxyl includes 2- (methylamino)-ethanol (MAE) whose chemical structure is shown in FIG. 2 IE.

[0229] The capture kinetics of capturing CO2 from the CCh-rich airstream 101 to form carbonate can be improved by the introduction of an additive such as a promoter species in the CO2 capture solution 114. In example implementations, the resulting carbonate-rich capture solution 111 produced by the capture sections 102A, 102B includes carbonates and bicarbonatesAttorney Docket No.: 30285-0050W01 and includes the promoter as well. An example composition of such a carbonate-rich capture solution 111 can include K2CO3 / KHCO3 and a promoter. Non-limiting examples of promoters include carbonic anhydrase, amines (primary, secondary, tertiary), zwitterionic amino acids, and boric acid. Non-limiting examples of additives include chlorides, sulfates, acetates, phosphates, surfactants, oxides and metal oxides. The carbonate-rich capture solution 111 (sometimes referred to herein as a “CCh-rich capture solution 111”) resulting from such a CO2 capture solution 114 can have a pH in the range of 11-13 and can have little residual hydroxide from the CO2 capture solution 114. In example implementations, additives that are not considered promoters can be used to improve the uptake of CO2 in the CO2 capture solution 114. For example, a surfactant can be added to the CO2 capture solution 114 to lower the surface tension of the CO2 capture solution 114 to improve the ability of the CO2 capture solution 114 to wet the material of a gas-liquid interface. Non-limiting examples of rate-enhancing additives include carbonic anhydrase, piperazine, monoethanolamine (MEA), diethanolamine (DEA), zinc triazacycles, zinc tetraazacycles, copper glycinates, hydroxopentaaminecobalt perchlorate, formaldehyde hydrate, saccharose, fructose, glucose, phenols, phenolates, glycerin, arsenite, vanadium pentoxide, hypochlorite, hypobromite, or other oxyanionic species.

[0230] In example implementations, at a given reference temperature, the density of the CO2 capture solution 114 is greater than the density of water at the same reference temperature. At comparable reference temperatures, in example implementations, the density of the CO2 capture solution 114 is at least 10% greater than the density of water. In example implementations, at comparable reference temperatures, the density of the CO2 capture solution 114 is approximately 10% greater than the density of water. The density and the viscosity of the CO2 capture solution 114 can vary depending on the composition of the CO2 capture solution 114 and the temperature. For example, at temperatures of 0°C to 20°C, a CO2 capture solution 114 comprising 1 M KOH and 0.5 M K2CO3 can have a density ranging from 1115-1119 kg / m3and a viscosity ranging from 1.3-2.3 mPa-s. In example aspects, at temperatures of 20°C to 0°C, a CO2 capture solution 114 comprising 2 M KOH and 1 M K2CO3 can have a density ranging from 1260-1266 kg / m3and a viscosity ranging from 1.8-3.1 mPa-s. In comparison, water has a density of 998 kg / m3and viscosity of 1 mPa-s at 20°C.

[0231] In example implementations, and referring to FIG. 3, CO2 from the CO2-rich airstream 101 is captured by contacting the CO2-rich airstream 101 with the CO2 capture solutionAttorney Docket No.: 30285-0050W01114 in the capture sections 102A, 102B. Reacting the absorbed CO2 from the CCh-rich airstream 101 with one or more CO2 capture species from the CO2 capture solution 114 can form the CO2- rich capture solution 111 including captured CO2, for example as carbonate, carbamate and / or carbamic acid species. The CCh-rich capture solution 111 can thus also be referred to as, for example, a the “carbonate-rich capture solution 111”. The composition of the CCh-rich capture solution 111 can vary in accordance with several factors including the nature of the CO2 capture solution 114 and the operational absorption conditions.

[0232] For example, in implementations of the present disclosure where the at least one CO2 capture species comprises an amine, CO2 is absorbed in the CO2 capture solution 114 and reacted with the amine to form the CCh-rich capture solution 111 which includes solids. Solids including carbamate solids, carbonate solids and carbamic acid solids can be referred to as carbon containing solids. In one example of such an implementation, the at least one CO2 capture species of the CO2 capture solution 114 includes isophorone diamine (IPDA), and CO2 is reacted with the amine to form the CCh-rich capture solution 111 which includes at least one of carbamic acid species, carbamate species and carbonate species (e.g., including carbamic acid solids). Depending on the solvent (aqueous and non-aqueous) of the CO2 capture solution 114, carbamic acid solids can be insoluble, such that the CCh-rich capture solution 111 forms a pumpable slurry.

[0233] For example, in implementations of the present disclosure where at least one CO2 capture species of the CO2 capture solution 114 includes one or more alkali hydroxides, CO2 is absorbed and reacted with the alkali hydroxide(s) of the CO2 capture solution 114 to form the CO2- rich capture solution 111 which includes carbonates. The carbonates can be carbonate solids such that the that the CCh-rich capture solution 111 forms a pumpable slurry.

[0234] For example, in implementations of the present disclosure where at least one CO2 capture species of the CO2 capture solution 114 is an alkali hydroxide (e.g., KOH), the carbonates (e.g., K2CO3, KHCO3, etc.) formed within the CO2-rich capture solution 111 can be reacted with another species such as an amine species. In example implementations, the amine species is IPDA. A solid precipitate resulting from the reaction, including solids such as carbamic acid solids, may be used to recover at least some of the CO2 captured from the dilute gas source. In such implementations of using two or more CO2 capture species, the CO2 capture process can benefit from the comparatively favourable capture kinetics associated with inorganic capture species such as alkali hydroxides, while also benefiting from the favorable regeneration kinetics associated withAttorney Docket No.: 30285-0050W01 organic capture species, for example. The additional chemical compounds may promote the precipitation of solids associated with the alkali hydroxide (e.g., KOH). Additional CO2-capture species that can be used, in combination with a first CO2-capture species, to precipitate solids from dissolved species include, but are not limited to at least one of a cyclic diamine or a bis- iminoguanidine. The additional chemical compounds may promote the precipitation of solids associated with the alkali hydroxide (ex: KOH) or hindered amine.

[0235] Reacting the CO2 from the CO2-rich airstream 101 with the CO2 capture solution 114 forms the CO2-lean gas stream 105 and the CO2-rich capture solution 111. The CO2-rich capture solution 111 can be processed to recover the captured CO2 for use and to regenerate the capture species to be reused in the CO2 capture solution 114. The CO24ean gas stream 105 can contain compounds of CO2 capture solution 114, and possibly also compounds of the CCh-rich capture solution 111. The compounds of the CO2 capture solution 114 and possibly also of the CO2-rich capture solution 111 can be in liquid and / or vapor phase, and are present in the flow of the CO2-lean gas stream 105, such that they can flow with the CCh-lean gas stream 105 to other components of the gas-liquid contactor 100 that are downstream of the capture sections, relative to the flow direction of gases through the capture sections. The terms “downstream” and “upstream” are used herein as positional descriptors, to describe the relative position of two or more components as a function of the flow direction of a corresponding liquid or gas. For example, if a first component is described as being downstream of a second component relative to a direction of gas flow, the first component receives the gas flow after the second component. Similarly, if a first component is described as being upstream of a second component relative to a direction of liquid flow, the first component receives the liquid flow before the second component.

[0236] In the configuration where the CO2 capture solution 114 comprises an alkali hydroxide, CO2 is absorbed by reacting with the alkali hydroxide to form the CCh-rich capture solution 111 which is carbonate-rich capture solution (e.g., K2CO3, Na2COs, or a combination thereof). The term “rich,” in example aspects, can mean that a stream contains more CO2 than the associated CCh-lean stream (in this case, the CO2 capture solution 114). The CCh-rich capture solution 111 can be processed to recover the captured CO2 for use and to regenerate the alkali hydroxide for use in the CO2 capture solution 114. In example implementations, recovered CO2 can be delivered downhole and sequestered in a geological formation, subsurface reservoir, carbon sink, or the like. In example implementations, the recovered CO2 can be used for enhanced oilAttorney Docket No.: 30285-0050W01 recovery by injecting the recovered CO2 into one or more wellbores to enhance production of hydrocarbons from a reservoir. In example implementations, recovered CO2 can be fed to a fuel synthesis system, which can include a syngas generation reactor. In example implementations, the recovered CO2 can be a feedstock for making any suitable carbon-based or carbon-including product, non-limiting examples of which include cement, plastics, and polymers.

[0237] The CCh-rich capture solution 111 can also include other components in smaller amounts, such as hydroxide ions, alkali metal hydroxide (e.g., KOH, NaOH), water, and impurities. For example, the carbonate-rich capture solution 111 can comprise between 0.4 M to 6 M K2CO3 and between 1 M to 10 M KOH. In example implementations, the carbonate-rich capture solution 111 can comprise an aqueous Na2CO.3-NaOH mixture. In example implementations, the carbonate-rich capture solution 111 can comprise a mixture of K2CO3 and Na2CO3. Referring to FIG. 3, the gas-liquid contactor 100 includes a housing 102. The housing 102 defines part of the corpus of the gas-liquid contactor 100 and provides structure thereto. The housing 102 includes exterior structure or walls that partially enclose any combination of interconnected structural members 115. The structural members 115 provide structural support and stability to the gas-liquid contactor 100 and provide a body for supporting components of the gas-liquid contactor 100 within the housing 102. The structural members 115 can include, but are not limited to, walls, panels, beams, frames, etc. The housing 102 may include other components as well, such as cladding, panels, etc. which help to close off parts of the housing 102 and define the enclosure of the housing 102. The housing 102 at least partially encloses and defines an interior 113 of the housing 102. The interior 113 of the housing 102 is an inner volume or inner space in which components of the gas-liquid contactor 100 are positioned. The housing 102 also includes openings 103 that allow for movement of gases into and out of the gas-liquid contactor 100. For example, and referring to FIG. 3, the housing 102 has one or more inlet(s) 1031. In the implementation of FIG. 3, the one or more inlet(s) 1031 are formed by the openings 103, such that the inlet(s) 1031 may be referred to herein as one or more inlet opening(s) 1031 through which the CCh-rich airstream 101 enters the interior 113 of the housing 102. The housing 102 has one or more outlet(s) 1030. In the implementation of FIG. 3, the one or more outlet(s) 1030 are formed by the openings 103, such that the outlet(s) 1030 may be referred to herein as one or more outlet opening(s) 1030 through which the CO2-lean airstream 105 exits the interior 113 of the housingAttorney Docket No.: 30285-0050W01102. In example aspects, the one or more outlet(s) 1030 extend from one or more gas-liquid interfaces of the gas-liquid contactor 100

[0238] In the example implementation of the gas-liquid contactor 100 of FIG. 3, the housing 102 defines two inlets 1031 and one outlet 1030. The outlet 1030 may be defined by a component of the gas-liquid contactor 100. For example, in the implementation of the gas-liquid contactor 100 of FIG. 3, the gas-liquid contactor 100 has a fan stack 107 with an upright orientation. The fan stack 107 extends upwardly from the housing 102 and helps to discharge the CCh-lean airstream 105. The fan stack 107 includes a fan cowling 117 that encloses a fan 212 that functions to move or flow gas flows into and out of the gas-liquid contactor 100. The outlet 1030 is positioned along the fan stack 107.

[0239] In such an implementation, the CO2-rich airstream 101 enters the interior 113 of the housing 102 along a substantially horizontal direction through one or both of the inlets 1031, and the CO2-lean airstream 105 exits the interior 113 along a substantially vertical direction through the outlet 1030. The outlet 1030 is located at the upper extremity of the fan stack 107. In implementations of the gas-liquid contactor 100 without a fan stack 107, the outlet 1030 may be located elsewhere. Other configurations for the inlets 1031 and outlets 1030 of the housing 102 are possible.

[0240] The housing 102 at least partially encloses and protects components of the gasliquid contactor 100 positioned in the interior 113 of the housing 102. One example of such a component is a packing section 106, which is protected from the surrounding atmosphere by the housing 102. As can be seen in FIG. 3, one or more packing sections 106, which are sometimes referred to herein collectively as “fill 106” or “packing 106”, are located within the interior 113 in a position adjacent to the one ormore inlets 1031. In this position, the one or more packing sections 106 receive the CCh-rich airstream 101 which enters the interior 113 via the one or more inlets 1031.

[0241] The one or more packing sections 106 function to increase transfer of CO2 present in the CCh-rich airstream 101 to a flow of the capture solution 114, in that the one or more packing sections 106 provide a large surface area for the capture solution 114 to disperse on, thereby increasing the reactive area between the CCh-rich airstream 101 and the capture solution 114. The capture solution 114 transforms the CCh-rich airstream 101 into the CCh-lean airstream 105 which is discharged from the one or more outlet(s) 1030 of the gas-liquid contactor 100. The packingAttorney Docket No.: 30285-0050W01 sections 106 receives the CO2 capture solution 114 and facilitates absorption of the CO2 present in the CCh-rich airstream 101 into the CO2 capture solution 114 on the packing sections 106, as described in greater detail below.

[0242] Referring to FIG. 3, one possible arrangement of the packing sections 106 includes two or more packing sections 106A, 106B. Each packing section 106A, 106B is positioned adjacent to and downstream of one of the inlets 1031. The packing sections 106 A, 106B are spaced apart from each other within the housing 102. The direction along which the packing sections 106A, 106B are spaced apart is parallel to the direction along which the CCh-rich airstream 101 flows through the packing sections 106A, 106B . The space or volume defined between the packing sections 106A, 106B and / or one or more structural members of the housing 102 is a plenum 108. The plenum 108 is flanked by the packing sections 106A, 106B. The plenum 108 is a void or space within the housing 102 into which gases flow downstream of the packing sections 106A, 106B (e.g., the CCh-lean airstream 105), and from which the CCh-lean airstream 105 flows out of the housing 102 through the outlet 1030. The plenum 108 is part of the interior 113 of the housing 102. The volume of the plenum 108 is less than a volume of the interior 113. In example implementations, the volume of the interior 113 of the housing 102 is approximately equal to the combined volume of the packing sections 106A, 106B and the plenum 108. Referring to FIG. 3, the packing sections 106A, 106B are positioned along the same level, or are positioned along the same horizontal lower plane, as the plenum 108.

[0243] Referring to FIG. 3, the plenum 108 may include an upper plenum portion 108U that is an uppermost portion of the plenum 108, and a lower plenum portion 108L that Is a lowermost portion of the plenum 108. A total height of the plenum 108 is defined as the height of the upper plenum portion 108U plus the height of the lower plenum portion 108L. Part of the upper plenum portion 108U is defined by housing plenum walls 102W of the housing 102, and a remainder of the upper plenum portion 108U is defined by the portion of the fan stack 107 positioned beneath the fan 212. The housing plenum walls 102W extend upwardly from a remainder of the housing 102. In some embodiments, and referring to FIG. 3, the housing plenum walls 102W are the uppermost portion of the housing 102. The height of the upper plenum portion 108U includes a lower height portion defined by the housing plenum walls 102W, and an upper height portion defined by the portion of the fan stack 107 positioned beneath the fan 212. In example implementations, the lower height portion defined by the housing plenum walls 102W isAttorney Docket No.: 30285-0050W01 two thirds of the height of the upper plenum portion 108U, and the upper height portion defined by the portion of the fan stack 107 positioned beneath the fan 212 is one third of the height of the upper plenum portion 108U. This configuration of the upper plenum portion 108U may reduce reingestion of part of the CCh-lean airstream 105 at the inlet 1031. Referring to FIG. 3, part of the upper plenum portion 108U, and thus part of the plenum 108, extends into the fan stack 107. After the CO2-rich airstream 101 flows through the packing sections 106 A, 106B, the CCh-lean airstream 105 flows through the plenum 108 before being discharged to the ambient environment. In other implementations of the gas-liquid contactor 100, the plenum is absent. As will be described in further detail herein, the gas-liquid contactor 100 may include one or more portions of passive and / or electrostatic drift eliminators 700 to remove or reduce CO2 capture solution 114 that may be entrained in the CCh-lean airstream 105 flowing through the plenum 108.

[0244] In the example implementation of the gas-liquid contactor 100 of FIG. 3, the CO2- rich airstream 101 enters the interior 113 of the housing 102 along a substantially horizontal direction through both of the inlets 1031. The CCh-rich airstream 101 then flows through the packing sections 106A, 106B along a substantially horizontal direction, where the CO2 present in the CCh-rich airstream 101 contacts the CO2 capture solution 114 present on the packing sections 106A, 106B and / or flowing in a substantially downward direction over the packing sections 106A, 106B. The exposed surface of the liquid fdm on the packing sections 106A, 106B is a gas-liquid interface between the CCh-rich airstream 101 and the CO2 capture solution 114. CO2 from the CO2-rich airstream 101 is absorbed into the liquid film to form the CCh-laden capture solution 111 and the CCE-lean airstream 105. The CCh-laden capture solution 111 flows downwardly off the packing sections 106A, 106B in a mixed solution with unreacted CO2 capture solution 114 and is collected. The CCE-rich airstream 101 treated by the packing sections 106A, 106B exits the packing sections 106A, 106B as the CO2-lean airstream 105. The CCh-lean airstream 105 from both packing sections 106A, 106B converges in the plenum 108, and then flows in a vertically upward direction out of the plenum 108 through the outlet 1030. The gas-liquid contactor 100 of FIG. 3 may be considered a dual-cell (because of the two packing sections 106A, 106B), crossflow air contactor. Other configurations of a gas-liquid contactor 10, 300, 400, 500, 600, 2100, 3100, 5000 are possible, as described in greater detail herein.

[0245] Each packing section 106 defines a packing depth 106D, which represents the distance traversed by the CCh-rich airstream 101 as it flows through the packing section 106. TheAttorney Docket No.: 30285-0050W01 packing depth 106D may be in the range of 2-10 meters. Each packing section 106 also defines a packing liquid travel dimension 106L (sometimes referred to herein as the “packing LTD 106L”), which represents the distance traversed by the capture solution 114 as it flows through the packing section 106. In the gas-liquid contactor 100 of FIG. 3, the packing depth 106D is transverse to the packing LTD 106L. In the gas-liquid contactor 100 of FIG. 3, the packing depth 106D is defined along a substantially horizontal direction, and the packing LTD 106L is a vertical dimension. In example implementations, the packing LTD 106L (, e.g., the height of each packing section 106) is greater than 2 m. In example implementations, the packing LTD 106L is greater than 5 m. In example implementations, the packing LTD 106L is between 2 m and 20 m. In example implementations, the packing depth 106D is greater than 3 m. In example implementations, the packing depth 106D is greater than 5 m. In example implementations, the packing depth 106D is between 3 m and 10 m. In other configurations of the gas-liquid contactor 100, the packing depth 106D and the packing LTD 106L may be defined differently, as described in greater detail below.

[0246] Referring to FIG. 3, each packing section 106 includes one or more structured packings 116. In the implementation of the packing sections 106 of FIG. 3, each packing section 106 includes multiple structured packings 116. Within one of the packing sections 106, each structured packing 116 is arranged adjacent to another structured packing 116. The structured packings 116 of each packing section 106 may be arranged adjacent to each other in the direction of one or more of the packing depth 106D, the packing LTD 106L, and a direction perpendicular to both of the packing depth 106D and the packing LTD 106L. Within one of the packing sections 106, in example implementations one structured packing 116 is attached to another structured packing 116. Within one of the packing sections 106, in example implementations the structured packings 116 of each packing section 106 are arranged next to one another with minimal separation or gaps along one or more of the packing depth 106D, the packing LTD 106L, and a direction perpendicular to both of the packing depth 10D and the packing LTD 106L.

[0247] The structured packings 116 may be arranged to form packing sections 106 of any desired shape or configuration. For example, and referring to FIG. 3, the structured packings 116 are arranged such that each packing section 106A, 106B includes at least one arrangement of the structured packings 116.

[0248] In the example implementation of the packing sections 106 of FIG. 3, each packing section 106A, 106B has a respective packing section height that is substantially equal to a heightAttorney Docket No.: 30285-0050W01 of the inlets 1031. Providing the packing sections 106 with substantially the same height as the height of the inlet 1031 may help to prevent or reduce the ability of the CCh-rich airstream 101 to bypass the packing sections 106 (e.g., flow around the packing sections 106), thereby helping to ensure that the greatest possible volume of CCh-rich airstream 101 is treated by the packing sections 106. By “substantially equal” or “substantially the same”, it is understood that the heights are approximately equal in value, with any differences being minimal compared to the overall height dimension, where said differences may result from manufacturing tolerances, packing installation requirements, and / or adjustments in dimensions to allow for seals, baffles or other features. Other configurations for the packing sections 106 are possible. For example, in another implementation, the heights of the packing sections 106A, 106B are less than the height of the inlet 1031, and any gaps between the packing sections 106A, 106B and the housing 102 are sealed using suitable techniques.

[0249] Referring to FIG. 3, the gas-liquid contactor 100 has, includes components of, or is functionally linked to, a liquid distribution system 120. The liquid distribution system 120 operates to move, collect and distribute the CO2 capture solution 114 and / or the CCh-laden capture solution 111. At least some of the features of the liquid distribution system 120 are supported by the housing 102. In the example implementation of FIG. 3, the support provided by the housing 102 includes structural support, in that components of the liquid distribution system 120 are structurally supported by the housing 102, such as by the structural members 115, so that loads generated by these components are supported by the housing 102. Some or all of the features of the liquid distribution system 120 may be part of the gas-liquid contactor 100, or part of DAC system 800, 900, 1200, 2000, 3000 (see, for example, FIGS. 11-16).

[0250] Referring to FIG. 3, the liquid distribution system 120 includes one or more liquid collection devices 109. Each liquid collection device 109 is configured to receive one or both of the CO2 capture solution 114 and the CCh-laden capture solution 111 and to hold a volume thereof temporarily or for a longer duration, thereby serving as a source of the CO2 capture solution 114 and / or of the CCE-laden capture solution 111. Each liquid collection device 109 may have any configuration or be made of any material suitable to achieve the function ascribed to it in the present description. For example, one or more of the liquid collection devices 109 may be opentopped, or partially or fully covered. In FIG. 3, one or more of the liquid collection devices 109 include, or are in the form of, basins. Other configurations of the liquid collection device 109 areAttorney Docket No.: 30285-0050W01 possible, such as a reservoir, a bed, a sheet, a culvert, a container, a receptacle, a network of pressurized pipes with openings or spray nozzles, or any other device capable of retaining liquid.

[0251] The liquid collection devices 109 of the liquid distribution system 120 include one or more top basins 104 and one or more bottom basins 110. The top basins 104 are supported by the housing 102. In example implementations, the top basins 104 are formed from portions of the housing 102. The top basins 104 are configured to at least partially enclose or store the CO2 capture solution 114. Referring to FIG. 3, the top basins 104 are each positioned at least partially above the packing sections 106. Referring to FIG. 3, the top basins 104 are positioned above the inlets 1031. Referring to FIG. 3, the top basins 104 are positioned beneath the upper plenum portion 108U. Part of the plenum 108 (e.g., the upper plenum portion 108U) thus extends beyond or above the top basins 104. When stored (at least transiently) within the top basins 104, the CO2 capture solution 114 is positioned to be flowed (e.g., through pumping, gravity flow or both) downwards, through the packing sections 106 and ultimately into the bottom basin 110. As the CO2 capture solution 114 is flowed through the packing sections 106, the CCh-rich airstream 101 is flowed through the packing sections 106 to contact the CO2 capture solution 114, through the plenum 108, and to an ambient environment as the CCh-lean airstream 105.

[0252] A process stream is formed by contacting the CCh-rich airstream 101 and the liquid CO2 capture solution 114, where the process stream is or includes the CCE-laden capture solution 111 having CO2 absorbed from the CO2-rich airstream 101 by the CO2 capture solution 114. The top basins 104 may each have any suitable form or feature for distributing the CO2 capture solution 114 over the packing sections 106. In the example implementation of the gas-liquid contactor 100 of FIG. 3, the liquid collection devices 109 include two top basins 104. Each top basin 104 is positioned above one of the packing sections 106A, 106B to distribute the CO2 capture solution 114 to the respective packing section 106A, 106B. The top basins 104 of FIG. 3 are fluidly isolated from one another (e.g., no fluid communication between the two top basins 104). Other configurations and numbers of the top basins 104 are possible. Other configurations for the distribution of the CO2 capture solution 114 over the packing sections 106 is possible. In one such possible configuration, the one or more of the liquid collection devices 109 include, or are in the form of, a network of pressurized pipes with openings or spray nozzles which distribute the CO2 capture solution 114 over the uppermost portions of the packing sections 106.Attorney Docket No.: 30285-0050W01

[0253] Referring to FIG. 3, the one or more bottom basins 110 are positioned at the bottom of the gas-liquid contactor 100 opposite the top basins 104. As can be seen in FIG. 3, the bottom basin 110 is positioned below the packing sections 106. The bottom basin 110 acts as a collection tank for the process stream (e.g., the CCh-laden capture solution 111). The CCh-laden capture solution 111 including absorbed CO2, as well as unreacted CO2 capture solution 114, collects in the bottom basin 110, and may then be pumped or otherwise moved out of the bottom basin 110 for further processing. For example, at least a portion of the liquids collected in the bottom basin 110 may be processed and then pumped for redistribution over the packing sections 106 for use in CO2 capture. In another example implementation, some or all of the liquids collected in the bottom basin 110 is pumped to the top basins 104 without being processed, for redistribution over the packing sections 106 for CO2 capture.

[0254] In another example implementation, some or all of the liquids collected in a liquid collection device, such as the bottom basin 110, are pumped to components of a DAC system 800, 900, 1200, 2000, 3000 (see, for example, FIGS. 11-16) for further processing, as described in greater detail below. The bottom basin 110 can be compatible with a containment structure and prevent loss of various CO2 capture solutions 114, many of which have corrosive, caustic or high pH properties. In example aspects, the bottom basin 110 can be lined or coated with one or more materials that are resistant to caustic induced corrosion or degradation. In example implementations of the gas-liquid contactor 100, components can be kept out of the bottom basin 110 holding the CO2 capture solution 114. Additionally, the gas-liquid contactor 100 can be designed to keep most or all the structural components out of the wettable area of the gas-liquid contactor 100, e.g., any portion of the gas-liquid contactor 100 that is in contact with the CO2 capture solution 114. Examples of wettable areas of the gas-liquid contactor 100 includes components supporting the packing sections 106. FIG. 3 depicts a single bottom basin 110. However, other configurations and numbers of bottom basins 110 are possible.

[0255] In example implementations, the gas-liquid contactor 100 includes vertically sectioned packing sections 106 with redistribution of the CO2 capture solution 114 between the vertically-spaced apart packing. For example, and referring to FIG. 3, the liquid collection devices 109 of the liquid distribution system 120 include one or more redistribution basins 119. Each packing section 106A, 106B includes a redistribution basin 119, which is positioned in the redistribution spacing of that packing section 106A, 106B. Thus, in the configuration of packingAttorney Docket No.: 30285-0050W01 sections 106A, 106B of FIG. 3, each redistribution basin 1 19 divides each packing section 106A, 106B into at least a top section and a bottom section. Each redistribution basin 119 is located vertically between the one or more top basins 104 and the bottom basin 110. Non-limiting examples of features of the redistribution basins 119 include basin walls, redistribution apertures, and redistribution nozzles. Thus, in the gas-liquid contactor 100, there may be a collector / distributor system between vertical sections of packing that collects fluid flowing from above and redistributes it evenly to the packing below. The description and one, some, or all of the advantages, and functions of features of the top basins 104 and of the bottom basin 110 apply mutatis mutandis to the redistribution basins 119.

[0256] Referring to FIG. 3, the CO2 capture solution 114 flows over the packing sections 106 in a direction that is substantially perpendicular or transverse to the average direction along which the CCh-rich airstream 101 flows through the packing sections 106, also known as a “cross flow” configuration. In another example implementation, the CO2 capture solution 114 flows over the packing sections 106 in a direction that is opposite to the average direction along which the CCh-rich airstream 101 flows through the packing sections 106, also known as a “counter flow” configuration. In another example implementation, the CO2 capture solution 114 flows over the packing sections 106 in a direction that is parallel with the direction along which the CCh-rich airstream 101 flows through the packing sections 106, also known as a “co-current flow” configuration. In another possible configuration, the CO2 capture solution 114 flows over the packing sections 106 according to a configuration that is a combination of one or more of cross flow, counter flow and co-current flow configurations.

[0257] The gas-liquid contactor 100 may include supports positioned within the packing sections 106 between the top basins 104 and bottom basin 110. For example, the packing sections 106 can include additional support, such as one or more structural members 115, for a specific portion of the packing sections 106, such as for an upper portion of the packing sections 106, so that the loads (e.g., the weight of the portion of structured packings 116 when dry plus the weight of the liquid hold up of the CO2 capture solution 114 on the portion of the structured packings 116) do not bear upon another portion of the packing sections 106 (e.g., a bottom portion of the packing sections 106). In example aspects, the packing sections 106 may not include the support. In example aspects, at least one structural support can be positioned between the structured packings 116 of the packing sections 106.Attorney Docket No.: 30285-0050W01

[0258] The liquid distribution system 120 may include any suitable componentry, such as piping, weir(s), pump(s), valve(s), manifold(s), etc., fluidly coupled in any suitable arrangement, to achieve the functionality ascribed to the liquid distribution system 120 herein. One non-limiting example of such componentry is one or more pump(s) 122, an example of which is shown in FIG. 3. The pumps 122 function to move liquids under pressure, such as the CO2 capture solution 114 and / or the CO2-laden capture solution 111, from their source to where they are used. Some nonlimiting examples of possible functions of the pumps 122 include moving the CO2 capture solution 114 to the top basins 104, moving the process streams from the bottom basin 110 to the redistribution basins 119, moving the CO2 capture solution 114 and / or the CCh-laden capture solution 111 from the bottom basin 110 to the top basins 104 for redistribution over the packing sections 106, moving the CO2 capture solution 114 and / or the C O2-laden capture solution 111 from the bottom basin 110 to components of the DAC system 800, 900, 1200, 2000, 3000 for further processing, and any combination of the preceding flows. The pumps 122 may thus be used to move liquid to, from and within the gas-liquid contactor 100.

[0259] A control system (e.g., control system 999 shown in FIG. 3 and also applicable to the gas-liquid contactors 10, 400, 500, and 600 according to the present disclosure) may be used to control the flow of fluid by the pumps 122 of the liquid distribution system 120. For example, a control system can be used to control the pumps 122 in order to pump the CO2 capture solution 114 from the bottom basin 110 to the top basins 104. The pumps 122 can also be controlled such that a constant velocity of flow is provided to the liquid distribution system 120 regardless of changes of liquid flow throughout the gas-liquid contactor 100.

[0260] The pumps 122 may help to distribute the CO2 capture solution 114 over the packing sections 106 at relatively low liquid flow rates, which may help to reduce costs associated with pumping or moving the CO2 capture solution 114. Further, low liquid flow rates of the CO2 capture solution 114 over the packing sections 106 may result in a lower pressure drop of the CO2- rich airstream 101 as it flows through the packing sections 106, which reduces the energy requirements of the device used for moving the CCh-rich airstream 101 across the packing sections 106 (e.g., a fan 212 described below). The pumps 122 may be configured to generate intermittent or pulsed flow of the CO2 capture solution 114 over the packing sections 106, which may allow for intermittent wetting of the packing sections 106 using relatively low liquid flows. The CO2 capture solution 114 sprayed, flowed, or otherwise distributed over the packing sections 106 isAttorney Docket No.: 30285-0050W01 collected in the bottom basin 110 and may then be moved by the pumps 122 back to the top basin 104, or sent downstream for processing.[002611 In example implementations, and referring to FIG. 3, the one or more pump(s) 122 of the liquid distribution system are operable to flow the CO2 capture solution 114 over each packing section 106 at a liquid loading rate ranging from 0.5 L / m2s to 10 L / m2s. In example implementations, the liquid loading rate is between 2 L / m2s and 6 L / m2s. The units L / m2s of the liquid loading rate refer to a given volume of the CO2 capture solution 114 covering a given area of the packing section 106, each second. The given area of the packing section 106 may refer to a plane area of a top of the packing section 106, such as the area of the packing section 106 underneath the top basin 104 (e.g., looking down on the top part of the packing section 106 from the top basin 104). When determined using the plane area, a liquid loading rate of 2 L / m2s means that the pump(s) 122 is configured to flow the CO2 capture solution 114 over each packing section 106 such that every second each square meter of the plane area of the packing section 106 receives 2 L of the CO2 capture solution 114. The given area of the liquid loading rate may not refer to the area of a surface of the structured packing 116. The liquid loading rate may refer to, or be reflective of, an initial flow condition where the CO2 capture solution 114 is applied to the top of the packing section 106. The liquid loading rate may not reflect subsequent flow conditions present lower down the packing section 106.

[0262] The liquid process streams in the gas-liquid contactor 100, as well as process streams within any downstream processes with which the gas-liquid contactor 100 is fluidly coupled, can be flowed using one or more flow control systems (e.g., control system 999). A flow control system can include one or more flow pumps (including or in addition to the pumps 122), fans, blowers, or solids conveyors to move the process streams, one or more flow pipes through which the process streams are flowed and one or more valves to regulate the flow of streams through the pipes. Each of the configurations described herein can include at least one variable frequency drive (VFD) coupled to a respective pump that is capable of controlling at least one liquid flow rate. In example implementations, liquid flow rates are controlled by at least one flow control valve.

[0263] In some embodiments, a flow control system can be operated manually. For example, an operator can set a flow rate for each pump or transfer device and set valve open or closed positions to regulate the flow of the process streams through the pipes in the flow controlAttorney Docket No.: 30285-0050W01 system. Once the operator has set the flow rates and the valve open or closed positions for all flow control systems distributed across the system, the flow control system can flow the streams under constant flow conditions, for example, constant volumetric rate or other flow conditions. To change the flow conditions, the operator can manually operate the flow control system, for example, by changing the pump flow rate or the valve open or closed position.

[0264] In some embodiments, a flow control system can be operated automatically. For example, the flow control system can be connected to a computer or control system (e.g., control system 999) to operate the flow control system. The control system can include a computer- readable medium storing instructions (such as flow control instructions and other instructions) executable by one or more processors to perform operations (such as flow control operations). An operator can set the flow rates and the valve open or closed positions for all flow control systems distributed across the facility using the control system. In such embodiments, the operator can manually change the flow conditions by providing inputs through the control system. Also, in such embodiments, the control system can automatically (that is, without manual intervention) control one or more of the flow control systems, for example, using feedback systems connected to the control system. For example, a sensor (such as a pressure sensor, temperature sensor or other sensor) can be connected to a pipe through which a process stream flows. The sensor can monitor and provide a flow condition (such as a pressure, temperature, or other flow condition) of the process stream to the control system. In response to the flow condition exceeding a threshold (such as a threshold pressure value, a threshold temperature value, or other threshold value), the control system can automatically perform operations. For example, if the pressure or temperature in the pipe exceeds the threshold pressure value or the threshold temperature value, respectively, the control system can provide a signal to the pump to decrease a flow rate, a signal to open a valve to relieve the pressure, a signal to shut down process stream flow, or other signals.

[0265] The gas-liquid contactor 100 has a gas-circulating device which functions to move or circulate gas flows into and out of the gas-liquid contactor 100. In the implementation of the gas-liquid contactor of FIG. 3, the gas-circulating device of the gas-liquid contactor 100 is a fan 212. The fan 212 functions to flow gases like ambient air, such that the CCh-rich airstream 101 is caused by the fan 212 to flow into the gas-liquid contactor 100, and such that the CCh-lean airstream 105 is caused by the fan 212 to be discharged from the gas-liquid contactor 100. The fan 212 thus functions to flow the CCh-rich airstream 101 and the CCh-lean airstream 105 in theAttorney Docket No.: 30285-0050W01 manner described herein. Referring to FIG. 3, the fan 212 is rotatable about a fan axis defined by a fan shaft. In the implementation of the fan 212 depicted in FIG. 3, the fan axis has an upright or vertical orientation. Other orientations for the shaft and for the fan axis are possible, as described in greater detail below. Referring to FIG. 3, the fan 212 is positioned upstream of the end of the fan stack 107 that defines the outlet 1030 and functions to induce a flow of the CO2-lean airstream 105 through the outlet 1030. In another possible configuration, the fan 212 is positioned elsewhere between the vertically-opposite ends of the fan stack 107 and upstream of the outlet 1030, such that the fan 212 flows the CO2-lean gas 105 through the outlet 1030. Referring to FIG. 3, the fan 212 is positioned downstream of, and above, the upper plenum portion 108U. Rotation of the fan 212 about the fan axis causes gases to flow into the inlets 1031 and through the gas-liquid contactor 100. For example, in the implementation of the gas-liquid contactor of FIG. 3, rotation of the fan 212 causes the CCh-rich airstream 101 to be drawn into the gas-liquid contactor 100 and causes the CCh-lean airstream 105 to be discharged from the gas-liquid contactor 100. The fan 212 may cause the CCh-rich airstream 101 to enter the packing sections 106 at airspeeds below 5 m / s. The fan 212 may cause the CCh-rich airstream 101 to enter the packing sections 106 at airspeeds between 0.1 m / s and 5 m / s.

[0266] The CCh-lean airstream 105 flowing through the plenum 108 and the fan stack 107 can include particles (or droplets) of CO2 capture solution 114 and / or of CCh-laden capture solution 111 entrained in the CCh-lean airstream 105. The CO2 capture solution 114 entrained in the CCh-lean airstream 105 is referred to herein as drift and can includes aerosolized chemicals that form at least a portion of the CO2 capture solution 114, such as potassium hydroxide (KOH), sodium hydroxide (NaOH) and / or combinations thereof. In example aspects, a drift eliminator 700 can be positioned downstream of the packing 106 and functions to eliminate drift (e.g., remove 100% of aerosolized sorbent particles) or to reduce the amount of drift (e.g., remove less than 100% of aerosolized sorbent particles) exiting the gas-liquid contactor 100 through the outlet 1030. The drift eliminator, if implemented as an electrostatic drift eliminator 700, can be coupled to a source of electrical power that applies an electrical charge to the electrostatic drift eliminator 700. The CO2 capture solution 114 is provided to the bottom basin 110. Some or all of the CO2 capture solution 114 collected in the bottom basin 110 may then be moved by the pumps 122 back to the top basin 104 for flowing back over the packing 106. Some or all of the CO2 capture solution 114 collected in the bottom basin 110 may then be moved by the pumps 122 to a regenerationAttorney Docket No.: 30285-0050W01 system (such as regeneration system 180, 880, 980, 1280 of the D AC system 800, 900, 1200, 2000, 3000).[002671 The gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 of the present disclosure can be adapted to be a spray tower, a liquid-gas scrubber, a venturi scrubber, a packed tower or another unit designed to remove at least a portion of carbon dioxide from the dilute gas source using the CO2 capture solution 114. The gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 can be a single or multi cell air contactor, a dual flow air contactor, or a combination thereof. When describing a gas-liquid contactor, a cell can refer to an absorption cell including at least one packing section of the present disclosure. A same gas-liquid contactor can include a single absorption cell or multiple absorption cells, the gas-liquid contactor 100 being for example a dual-cell contactor. The multiple absorption cells can be in fluid communication with a single outlet plenum or separate outlet plenums in a single gas-liquid contactor. A CO2 capture system, such as the DAC system 800, 900, 1200, 2000, 3000 (see FIGS. 11 to 16), can include a single gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 or multiple gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 provided in series or in parallel. The gas-liquid contactor 100 of FIG. 3 can be adapted to operate in crossflow, counterflow, co-current flow, or a combination thereof, as exemplified in FIGS. 1, 6 and 9.

[0268] FIGS. 4-10 are schematic diagrams of example implementations of a gas-liquid contactor that includes at least one energy transfer module according to the present disclosure. FIGS. 4-8 show implementations of at least one energy transfer module 20 being an energy transfer wheel whereas FIGS. 9 and 10 show an implementation of the at least one energy transfer module being an energy transfer belt.

[0269] For example, FIG. 4 shows an implementation of a gas-liquid contactor 5000 including at least one energy transfer module 20 being operated in a co-current mode. The gasliquid contactor 5000 includes at least one upper inlet 5103iu. As the dilute fluid source 1 (e.g., atmospheric air) enters the flow path 8 along a substantially vertical direction through the at least one upper inlet 5103iu (e.g., located in an upper wall 5171 of the housing 5102), the dilute fluid source 1 is flowed to the inlet plenum and through at least a portion of the packing section 5106 to form the CCh-lean gas stream 7. The CO2-lean gas stream 7 flows out of the packing section 5106 (e.g., downwardly), is deflected from a downward flow to an upward flow by turning at a 180° angle and flows into the outlet plenum 5108 along a substantially vertical direction (e.g., upwardly)Attorney Docket No.: 30285-0050W01 through the outlet 5103o. In the example implementation of FIG. 4, the outlet 5103o is located at the upper extremity of a fan stack 5107. Other configurations that the ones shown in FIG. 4 for the upper inlets 5103iu and outlet 5103o of the gas-liquid contactor 5000 are possible.

[0270] In the implementation of FIG. 4, the at least one energy transfer module 20 is positioned within the housing 5102 and across the flow path 8 of the dilute fluid source 1 / CO2- lean gas stream 7. For example, the at least one energy transfer module 20 can be positioned upstream of the at least one upper inlets 5103iu and outlet 5103o such that energy can be recovered to the dilute fluid source 1 before entering the at least one packing section 5106 and can be transferred back to the CCh-lean gas stream 7 before being flowed to the at least one outlet 5103o. In example implementations, referring to FIG. 4, the at least one energy transfer module 20 includes two adjacent thermal transfer wheels 200 that are laterally spaced across the gas-liquid contactor 5000 so as to be positioned above the upper wall 5171 and beneath the fan 5112 in a symmetric fashion with respect to vertical plane 5177. The positioning of the liquid distribution system 120 for supplying the CO2 capture solution 114 to spray nozzles 5129 that are mounted about the upper wall 5171 can be adapted to bypass the at least one energy transfer module 20 and be positioned downstream of the energy transfer module 20.

[0271] In other implementations where the co-current gas-liquid contactor 5000 can further include at least one side inlet (e.g., located in a side wall 5170 a, 5170b of the housing 5102), additional dilute fluid source 1 entering the flow path 8 through the at least one side inlet can mix with CCh-lean gas stream 7 flowing vertically downward through the portion of the packing section 5106 to form a collective / mixed gas stream that flows vertically downward through remaining portions of the packing section 5106.

[0272] In example implementations, referring to FIG. 5, the gas-liquid contactor 5000 includes multiple fan stacks 5107, for example a pair of fan stacks 5107a, 5107b, each fan stack 5107a, 5107b receiving the CCh-lean gas stream 7 exiting a corresponding energy transfer module 200 located below each fan stack 5107. In example implementations, a partition wall 5176 is positioned between the thermal transfer wheels 200 such that the CCh-lean gas stream 7 exiting one energy transfer module 200 is not communicated to the laterally adjacent energy transfer module 200 and / or fan stack 5107a, 5107b.

[0273] Still referring to FIG. 5, in example implementations, the gas-liquid contactor 5000 includes a top member or layer 202 being a slanted inlet, filter, grid, screening or cellular louversAttorney Docket No.: 30285-0050W01 to protect the upper inlet 5103iu and componentry adjacent thereto (e.g., the liquid distribution system 120, spray nozzles 129, the thermal transfer wheel 200, etc. as seen in FIG. 4) from solid debris / particles (animals, hail, pollens, etc.) that may be ingested by the gas-liquid contactor 5000. In example implementations, referring to FIGS. 1 and 4 for example, an upper wall 18, 5171 of the housing 2, 5102 can be configured as the top member or layer preventing debris from entering the interior of the housing 2. For example, the upper wall 18, 5171 can be, or include a screen or screen sections.

[0274] Referring to FIG. 4, in example implementations, the housing 5102 of the gas-liquid contactor 5000 can include at least one bottom wall, for example a pair of bottom walls 5173, 5175, that is angled with respect to a horizontal axis and incline in a downward direction to deflect the CCh-lean gas stream 7 towards the at least one outlet 51030. In example implementations, the bottom walls 5173, 5175 define a funnel section 5174 of the gas-liquid contactor 5000 that is positioned downstream of and adjacent to the packing sections 5106. For example, the at least one bottom wall 5173, 5175 can be downwardly tapered towards the bottom basin at an angle of at most 10%, at most 9%, at most 8%, at most 7%, at most 6%, or at most 5% with respect to the horizontal axis. As the CCh-lean gas stream 7 changes direction to flow upwards through the outlet plenum 5108, through the at least one energy transfer module 20 and through outlet 51030, the density of the CO2 capture solution 114 causes CO2 capture solution 114 entrained in the CO2-lean gas stream 7 to exit the CO2-lean gas stream 7 and fall downwards into a bottom basin 5110 of the housing 5102. As a result, the defecting of the CO2-lean gas stream 7 reduces drift of the CO2 capture solution 114 exiting the gas-liquid contactor 5000.

[0275] The description and one, some, or all of the advantages, and functions of features of gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100 apply mutatis mutandis to the gas-liquid contactors 5000 of the present disclosure, and vice-versa. For example, certain components and details of the gas-liquid contactor 5000 are not shown in FIGS. 4 and 5 but are described and shown elsewhere in the present disclosure (such as FIG. 3), and such components can be implemented in the gas-liquid contactor 5000. In another example, the gas-liquid contactor 10 can include two fans 5112a, 5112b located downstream of at least one energy module 20 and an upper wall 18 being a top member 202 as found in gas-liquid contactor 5000.

[0276] FIG. 6 shows a schematic diagram of another example implementation of a gasliquid contactor 400 that includes at least two energy transfer modules 402, 440 upstream of eachAttorney Docket No.: 30285-0050W01 inlet plenum 9a, 9b along the flow path 8. Generally, gas-liquid contactor 400 operates to capture carbon dioxide (CO2) from the atmosphere (e.g., ambient or atmospheric air) or from another dilute fluid source that contains dilute concentrations of CO2 as described herein. Certain components and details of the gas-liquid contactor 400 are not shown here but are described and shown elsewhere in the present disclosure (such as in FIGS. 3 to 5), and such components can be implemented in the gas-liquid contactor 400.

[0277] In the illustrated example of FIG. 6, gas-liquid contactor 400 can include many of the same components as gas-liquid contactor 10, 100, 300, 500, 600, 2100, 3100, 5000 and the description of such components applies mutatis mutandis to the same components in FIG. 6. As shown in the example implementation of gas-liquid contactor 400, two or more energy transfer modules (labeled 402 and 440) are positioned in the housing 2 and, more particularly, within the flow path 8 to produce the CCh-rich gas stream 453 that is flowed to the at least one packing section 12a, 12b, 12c. The gas-liquid contactor 400 of FIG. 6 can be considered a dual cell gasliquid contactor 400 because the dilute fluid source 1, such as atmospheric air, travels through separate gas-liquid interfaces provided by the packing sections 12a, 12b, 12c, in that the dilute fluid source 1 entering via one of the inlets 4a flows through the inlet plenum 9a and through the at least one packing section 12a, 12b, 12c and the dilute fluid source 1 entering via the other inlet 4b flows through the inlet plenum 9b and through at least one separate packing section 12b, 12a. Thus, in this example FIG. 6, there are four energy transfer modules (two per cell, as shown, with a first pair of energy transfer modules 402 and a second pair of energy transfer modules 440). However, in alternative implementations, the gas-liquid contactor 400 can be a single cell gasliquid contactor (as shown in FIGS. 11 and 12), where the dilute fluid source 1 entering via the at least one inlet 4 flows through at least one packing section 12a, 12b, 12c being provided in fluid communication with a single inlet plenum 9, with a first energy transfer module 402 and a second energy transfer module 440.

[0278] As shown in this example, each energy transfer module 402, 440 (of four energy transfer modules 402, 440 being illustrated in FIG. 6) includes a first airflow circuit 404, 444 being in fluid communication with the inlet plenum 9a or 9b and a second airflow circuit 406, 442 being in fluid communication with the outlet plenum 13. The first airflow circuit 404, 444 of each energy transfer module 402, 440 includes an inlet 408, 446 and an outlet 410, 448. The second airflow circuit 406, 442 includes an inlet 412, 452 and an outlet 414, 450. Generally, first airflow circuitAttorney Docket No.: 30285-0050W01404, 444 and second airflow circuit 406, 442 are fluidly decoupled from each other, such that no gas (e.g., air) flows between the first airflow circuit 404, 444 and the second airflow circuit 406, 442. However, first airflow circuit 404, 444 and second airflow circuit 406, 442 (as explained with reference to FIGS. 2 A and 2B) are in energy communication with each other, such that energy can be transferred between airflows that flow through the respective first airflow circuit 404, 444 and second airflow circuit 406, 442.

[0279] As further shown in this example, referring to FIG. 6, at least one heater 420 is positioned in the flow path 8 between the energy transfer module 402 and the energy transfer module 440. FIG. 6 shows a dual cell configuration including two heaters 420, each heater 420 being positioned between the two energy transfer modules 402, 440 of a same absorption cell side. As shown, each heater 420 (which can be an electric heater, fluid-to-fluid heat exchanger, or other type of heater) is positioned vertically between the outlet 410 of energy transfer module 402 and the inlet 446 of energy transfer module 440. During operation, as described later, the at least one heater 420 optionally heats an airflow that exits the outlet 410 of the first airflow circuit 404 of the first energy transfer module 402 and then (once heated) enters the inlet 446 of the first airflow circuit 444 of the second energy transfer module 440.

[0280] In this example gas-liquid contactor 400, each energy transfer module 402 is a thermal energy transfer module, e.g., a sensible heat energy transfer module for which the transferred energy is sensible heat. During operation of the gas-liquid contactor 400 (and the thermal energy transfer modules 402), sensible heat from an airflow downstream of the at least one packing sections 12a, 12b, or 12c (e.g., the CCh-lean airstream 455) is transferred by the thermal energy transfer modules 402 to an airflow upstream of the at least one packing(s) 12a, 12b, or 12c (more specifically the dilute fluid source 1, such as atmospheric air).

[0281] Further, in the example gas-liquid contactor 400, each energy transfer module 440 is an enthalpy transfer module (e.g., the transferred energy is enthalpy). During operation of the gas-liquid contactor 400 (and the enthalpy transfer modules 440), enthalpy or moisture (or both) from the airflow downstream of the packing(s) 12a, 12b, or 12c (e.g., the CCh-lean airstream 455) is transferred by the enthalpy transfer modules 440 to an airflow upstream of the packing(s) 12a, 12b, or 12c (e.g., the CCh-rich airstream 451 which has flowed through the energy transfer modules 402 and the at least one heater 420).Attorney Docket No.: 30285-0050W01

[0282] In operation of the dual-cell gas-liquid contactor 400, generally, the at least one fan 11 draw the dilute fluid source 1, such as atmospheric air, into the inlets 4a, 4b and through the first airflow circuits 404 of the first energy transfer modules 402. The at least one fan 11 also functions to flow the CCh-lean airstream 455 from the at least one packing section 12a, 12b, 12c in the outlet plenum 13 and through the second airflow circuits 442 of the second energy transfer modules 440. The CCh-lean airstream 455 transfers enthalpy and / or moisture to heated airstreams 451 that have been heated (with sensible heat) through the first airflow circuit 404 of the energy transfer modules 402 and, optionally, heaters 420. A lower enthalpy, drier CCh-lean airstream 459 leaves the outlet 454 of the second airflow circuits 442 of the second energy transfer modules 440 and then enters the inlet 412 of the second airflow circuits 406 of the first energy transfer modules 402. Sensible heat is transferred from the CCh-lean airstream 459 to the dilute fluid source 1 in the first energy transfer modules 402. The heated dilute fluid source 1 leaves the outlets 410 of first airflow circuits 404 as the heated CCh-rich airstream 451 and then is (optionally) further heated by the at least one heater 420. Heated CCh-rich airstream 451 enters the inlet 446 of the first airflow circuits 444 of the second energy transfer modules 440, where it gains enthalpy and / or moisture and leaves the second energy transfer modules 440 as a (warmer and increased relative humidity) CCh-rich airstream 453.

[0283] The example gas-liquid contactor 400 of FIG. 6, in example aspects, can be operated in any environment but, in particular, an environment in which the atmospheric air is not considered overly dry. The gas-liquid contactor 400, in particular, can be operated in multiple modes of operation, which generally differ based on the operational characteristics of the heaters 420. For example, a first mode of operation can be considered a water neutral mode. In the water neutral mode of operation, for example, the first (thermal) energy transfer modules 402 and the at least one heater 420, in combination, can raise a temperature (e.g., dry bulb) of the dilute fluid source 1 a moderate amount (for example, between 5 and 10°F), thereby lowering a relative humidity of the dilute fluid source 1, before the dilute fluid source 1 (as heated CCh-rich airstream 451) enters the second (enthalpy) energy transfer modules 440. By modulating operation of the at least one heater 420 (such as modulating heater temperature), a moisture content of CCh-rich airstream 453 that leaves the energy transfer modules 440 can be controlled such that a moisture content of the exhaust air 3 matches (exactly, substantially, or closely) a moisture content of the dilute fluid source 1.Attomey Docket No.: 30285-0050W01

[0284] In the example water neutral mode of operation of the gas-liquid contactor 400, the at least one heater 420 may be optional - or may be deactivated if present - should sufficient heat be added to the dilute fluid source 1 by the first (thermal) energy transfer modules 402. For example, operation of the first (thermal) energy transfer modules 402 can preserve heat already present in the airstreams through the gas-liquid contactor 400 and minimizes an amount of additional heat needed to be added by the at least one heater 420. As warmer air allows for the absorption of more water (warm air can possess more water vapor - moisture - than cold air), heated CCh-rich airstream 451 can absorb more moisture from the CCh-lean airstream 455 in the second (enthalpy) energy transfer modules 440. Therefore, control of the at least one heater 420 (such as by the flow control system 999) can provide for as-needed or intermittent heat added to heated CCh-rich airstream 451 by the at least one heater 420 depending on an exit air temperature of the CCh-rich airstream 451 from the outlet 410 of the first airflow circuit 404 of the first energy transfer modules 402 (or other criteria, such as relative humidity of exhaust air 3).

[0285] Another example mode of operation of the gas-liquid contactor 400 can be considered a water generation mode. In the water generation mode, for example, the at least one heater 420 can be operated (such as by flow control system 999) so that the moisture content of the exhaust air 3 is less than the moisture content of the CCh-rich airstream 453. Such a moisture transfer represents a generation of water by the gas-liquid contactor 400. The water generated in the water generation mode could be used as make-up water in the gas-liquid contactor 400, or for other purposes of the DAC system 800, 900, 1200, 2000, 3000.

[0286] In the example water generation mode of operation of the gas-liquid contactor 400, the at least one heater 420 can be operated (e.g., continuously or otherwise) to elevate a temperature of heated CCh-rich airstream 451 as high as practical or possible. By elevating the temperature, the relative humidity of the heated CCh-rich airstream 451 is lowered, thereby allowing the heated CCh-rich airstream 451 to absorb more moisture in the second energy transfer modules 440. The resulting CC -rich airstream 453 becomes water- saturated and / or has a higher relative humidity than the exhaust air 3.

[0287] The gas-liquid contactor 400 of FIG. 6 can be operated to provide the CCh-rich airstream 453 with a specific moisture content that allows for optimising the transfer of CO2 from the CCh-rich airstream 453 to the CO2 capture solution 114 flowing along the at least one packing section 12b, 12a, 12c. For example, if it is desired to increase the moisture content of the CO2-Attorney Docket No.: 30285-0050W01 rich airstream 453 provided to the at least one packing section 12b, 12a, 12c, the outlet temperature of the at least one heater 420 can be increased to warm the heated CCh-rich airstream 451 and increase its temperature, thereby lowering the relative humidity of the heated CCh-rich airstream 451 and allowing it to absorb more moisture in the second energy transfer modules 440. The CO2 capture solution 114 may more efficiently absorb CO2 from the CCh-rich airstream 453 if the CO2- rich airstream 453 has a high relative humidity and / or a higher temperature. Similarly, if it is desired to decrease the moisture content of the CCh-rich airstream 453 provided by the CO2 capture solution 114 in the at least one packing section 12b, 12a, 12c, the outlet temperature of the at least one heater 420 can be decreased (or the at least one heater 420 can be turned off) to provide the heated C Ch-rich airstream 451 with a lower temperature, thereby increasing the relative humidity of the heated CCh-rich airstream 451 and reducing its ability to absorb moisture in the second energy transfer modules 440.

[0288] FIG. 7 shows a schematic diagram of another example implementation of a gasliquid contactor 500 that also includes at least two energy transfer modules 502, 540 upstream of each inlet plenum 9a, 9b along the flow path 8. Generally, the gas-liquid contactor 500 operates to capture carbon dioxide (CO2) from the atmosphere (e.g., ambient or atmospheric air) or from another dilute fluid source 1 that contains dilute concentrations of CO2 (as described herein). Certain components and details of the gas-liquid contactor 500 are not shown here but are described and shown elsewhere in the present disclosure (such as FIG. 3 to 6), and such components can be implemented in the gas-liquid contactor 500.

[0289] In the illustrated example of FIG. 7, gas-liquid contactor 500 includes many of the same components as gas-liquid contactor 10, 100, 300, 400, 600, 2100, 3100, 5000, and the description of such components applies mutatis mutandis to the same components in FIG. 7. As shown in the example implementation of gas-liquid contactor 500, at least two energy transfer modules (labeled 502 and 540) are positioned in the housing 2 and, more particularly, within the flow path 8. The gas-liquid contactor 500 of FIG. 7 can be considered a dual cell gas-liquid contactor 500 because the dilute fluid source 1, such as atmospheric air, travels through separate inlet plenums 9a, 9b being in fluid communication with separate packing sections, in that the dilute fluid source 1 entering via the at least one inlet 4a flows through at least one packing section 12b, 12a and the dilute fluid source 1 entering via the other at least one inlet 4b flows through one or more separate packing section 12b, 12a. Thus, in this example, there are four energy transferAttorney Docket No.: 30285-0050W01 modules (two per cell, as shown, with a first pair of energy transfer modules 502 and a second pair of energy transfer modules 540). However, in alternative implementations, the gas-liquid contactor 500 can be a single cell gas-liquid contactor, where the dilute fluid source 1 entering via the at least one inlet 4 flows through only one inlet plenum 9 being in fluid communication with at least one packing section 12a, 12b, 12c, via a first energy transfer module 502 and a second energy transfer module 540.

[0290] As shown in this example, each energy transfer module 502, 540 includes a first airflow circuit 504, 544 and a second airflow circuit 506, 542. The first airflow circuit 504, 544 includes an inlet 508, 546 and an outlet 510, 548. The second airflow circuit 506, 542 includes an inlet 512, 552 and an outlet 514, 554. Generally, first airflow circuit 504, 544 and second airflow circuit 506, 542 are fluidly decoupled from each other, such that no gas (e.g., air) flows between the first airflow circuit 504, 544 and the second airflow circuit 506, 542. However, first airflow circuit 504, 544 and second airflow circuit 506, 542 (as explained with reference to FIGS 2A and 2B) are in energy communication with each other, such that energy can be transferred between airflows that flow through the respective first airflow circuit 504, 544 and second airflow circuit 506, 542.

[0291] In this example gas-liquid contactor 500, each first energy transfer module 502 is an enthalpy transfer module (e.g., the transferred energy is enthalpy). During operation of the gasliquid contactor 500 (and the first energy transfer modules 502), enthalpy or moisture (or both) from the airflow downstream of the at least one packing section 12a, 12b, or 12c (the CC -lean airstream 555) is transferred by the first energy transfer modules 502 to an airflow upstream of the at least one packing sections 12a, 12b, or 12c (the dilute fluid source 1 which flows through the first energy transfer modules 502).

[0292] Further, in the example gas-liquid contactor 500, each second energy transfer module 540 is a thermal energy transfer module, and more particularly a sensible heat energy transfer module (e.g., the transferred energy is sensible heat). During operation of the gas-liquid contactor 500 (and the second (thermal) energy transfer modules 540), sensible heat from an airflow downstream of the at least one packing section 12a, 12b, or 12c (in other words, a CO2- lean airstream 555) is transferred by the second energy transfer modules 540 to an airflow upstream of the at least one packing section 12a, 12b, or 12c (a CO2-rich airstream 551 and, more specifically dilute fluid source 1). Positioning the second energy transfer modules 540 between the first energyAttomey Docket No.: 30285-0050W01 transfer modules 502 and the at least one packing section 12a, 12b, or 12c (within each inlet plenum 9a, 9b of the flow path 8) may help to reduce the duty on the first energy transfer modules 502 and may also serve to eliminate drift (e.g., liquid aerosolized particles) in the exhaust air 3 flowing from the gas-liquid contactor 500. For example, the second energy transfer modules 540 acting as sensible heat transfer modules help to lower the temperature of the CCh-lean airstream 555, which may cause some water vapour entrained in the CCh-lean airstream 555 to condense and collect in the bottom basin 521. By helping to condense out some of the water content in the CCh-lean airstream 555, the second energy transfer modules 540 help to reduce the moisture content of the CCh-lean airstream 555 flowing from outlet plenum 13 upstream of the first energy transfer modules 502, thereby lowering the moisture-transfer duty of the first energy transfer modules 502 and reducing liquid aerosolized particles (e.g., drift or mist) in the exhaust air 3.

[0293] As further shown in this example, at least one heater 520 is positioned in the basin 521 (such as a bottom basin) of the gas-liquid contactor 500. The basin 521 collects the draining CCh-capture solution 523 that flows into the basin 521 from the at least one packing section 12a, 12b, or 12c (as a CCh-rich capture solution 523 having absorbed CO2 from the dilute fluid source 1). As shown, the at least one heater 520 (which can be an electric heater, fluid-to-fluid heat exchanger, or other type of heater) is positioned to heat the CCh-rich capture solution 523 before at least a portion of the CCh-rich capture solution 523 is redistributed back to the at least one packing section 12a, 12b, or 12c to further absorb CO2 from the dilute fluid source 1. As shown in this example, a heating supply fluid 561 is flowed to the at least one heater 520 (as a fluid-to- fluid heat exchanger), heats the CCh-rich capture solution 523, and then a heating return fluid 563 leaves the at least one heater 520. A heat source 531, which, for example, can be a waste heat source from or within the DAC system 800, 900, 1200, 2000, 3000 provides the heat energy to reheat the heating return fluid 563 and form the heating supply fluid 561.

[0294] In operation of the gas-liquid contactor 500, generally, the at least one fan 11 draws the dilute fluid source 1, such as atmospheric air, into the inlets 4a, 4b and through first airflow circuits 504 of the first energy transfer modules 502. Simultaneously, the at least one fan 11 flows the CCh-lean airstream 555 from the at least one packing section 12a, 12b, 12c through second airflow circuits 542 of the second energy transfer modules 540. The CCh-lean airstream 555 transfers sensible heat to a CCh-rich airstream 551, whose relative humidity has been increased through the first airflow circuit 504 of the second energy transfer modules 502. A cooled CO2-Attorney Docket No.: 30285-0050W01 lean airstream 557 leaves the outlets 554 of the second airflow circuits 542 of the second energy transfer modules 540 and then enters the inlets 512 of the second airflow circuits 506 of the first energy transfer modules 502. Enthalpy and / or moisture is transferred from the cooled CCh-lean airstream 557 to the dilute fluid source 1 in the first energy transfer modules 502. The humidified dilute fluid source 1 leaves the outlets 510 of first airflow circuits 504 of the first energy transfer modules 502 as the CCh-rich airstream 551. Airstream 551 enters the inlets 546 of the first airflow circuits 544 of the second energy transfer modules 540, where it gains sensible heat and leaves the second energy transfer modules 540 as a (warmer) CCh-rich airstream 553.

[0295] The example gas-liquid contactor 500 of FIG 7, in example aspects, can be operated in any environment but, in particular, an environment in which it is advantageous to provide heat into the airstreams via the CCh-rich capture solution 523. Such environments can include, for example, a process environment that produces waste heat, such as the DAC system 800, 900, 1200, 2000, 3000 of the present disclosure.

[0296] The gas-liquid contactor 500 can be operated in a bulk heating mode of operation. In the bulk heating mode of operation, for example, the at least one heater 520 operates to raise a temperature of the CCh-rich capture solution 523. It may be desirable to heat the CCh-rich capture solution 523 in the basin 521 (e.g., bottom basin) so that its temperature is increased before the warmed CCh-rich capture solution 523 is redistributed from the basin 521 to flow over the at least one packing section 12a, 12b, or 12c, because the warmed CCh-rich capture solution 523 may improve the CCh capture kinetics during gas-liquid contact. While improved CO2 capture kinetics are desirable, using a warmer CCh capture solution (upon redistributing the CCh-rich capture solution 523) during gas-liquid contact may increase the evaporative losses described above, such that water may be lost from the gas-liquid contactor 500 and need to be made-up or replenished. The energy transfer modules 502, 540 of the gas-liquid contactor 500 help to reduce or prevent these evaporative losses during the bulk heating mode, while still allowing the gas-liquid contactor 500 to benefit from the improved CCh capture kinetics resulting from the warmed CCh-laden capture solution 523. For example, the CCh-lean airstream 555 flowing from the at least one packing section 12a, 12b, or 12c has a high moisture content and / or is saturated with water.

[0297] As the CCh-lean airstream 555 flows through the second energy (sensible heat) transfer modules 540, its temperature is reduced, thereby forming the cooled CCh-lean airstream 557. The cooled CCh-lean airstream 557 still has a high moisture content and is flowed to the firstAttorney Docket No.: 30285-0050W01 energy (moisture-enthalpy) transfer modules 502 which transfers some or all of the moisture content to the dilute fluid source 1, thereby forming the increased-moisture content CCh-rich airstream 551 flowing from the outlet 510 of the first energy transfer modules 502 and the drier exhaust air 3 flowing out of the gas-liquid contactor 500 from the outlet 6. The energy transfer modules 502, 540 can allow for at least a portion of the heat and moisture transferred between fluid streams / airflows of the gas-liquid contactor 500 to remain in the gas-liquid contactor 500. The energy transfer modules 502, 540 can allow for bulk, excess or waste heat from the DAC system 800, 900, 1200, 2000, 3000 to be employed in the gas-liquid contactor 500 to increase CO2 capture, while minimising or preventing evaporative losses normally associated with contacting warmer liquid streams with cooler gas streams.

[0298] The energy transfer modules 20, 200, 250, 402, 440, 502, 540 and heaters 420, 520 can be arranged in any combination, to achieve desirable results such as enhanced CO2 capture kinetics and efficiency, and / or improved water retention or generation. One example of a gasliquid contactor 600 employing such a combination of energy transfer modules 20, 200, 250, 402, 440, 502, 540 and heaters 420, 520 is illustrated in FIG. 8. FIG. 8 shows a schematic diagram of another example implementation of a gas-liquid contactor 600 that includes at least three energy transfer modules 642, 640, and 602 according to the present disclosure being positioned upstream of each inlet plenum 9a, 9b along the flow path 8 (the inlet plenums 9a, 9b being positioned upstream of the first encountered packing section of the at least one packing section 12a, 12b). Generally, gas-liquid contactor 600 operates to capture carbon dioxide (CO2) from the atmosphere (e.g., ambient or atmospheric air) or from another dilute fluid source that contains dilute concentrations of CO2 (as described herein). Certain components and details of the gas-liquid contactor 600 are not shown here but are described and shown elsewhere in the present disclosure (such as in FIGS. 3 to 7), and such components can be implemented in the gas-liquid contactor 600.

[0299] In the illustrated example of FIG. 8, gas-liquid contactor 600 includes many of the same components as gas-liquid contactor 10, 100, 300, 400, 500, 2100, 3100, 5000, and the description of such components applies mutatis mutandis to the same components in FIG. 8. As shown in the example implementation of gas-liquid contactor 600, at least three energy transfer modules (labeled 602, 640, and 642) are positioned in the housing 2 and, more particularly, within the flow path 8 in fluid communication with each inlet plenum 9a, 9b. The gas-liquid contactorAttorney Docket No.: 30285-0050W01600 of FIG. 8 can be considered a dual cell gas-liquid contactor 600 because the dilute fluid source 1 travels through separate inlet plenums 9a, 9b upstream of separate packing sections 12a, 12b, in that the dilute fluid source 1 entering via one inlet 4a flows through the at least one gas-liquid interface 12b, 12a, or 12c and the dilute fluid source 1 entering via the other inlet 4b flows through at least one separate packing section 12b, 12a. Thus, in this example, there are six energy transfer modules (three per cell, as shown, with a first pair of energy transfer modules 602, a second pair of energy transfer modules 640, and a third pair of energy transfer modules 642). However, in alternative implementations, the gas-liquid contactor 600 can be a single cell gas-liquid contactor, where the dilute fluid source 1 entering via the at least one inlet 4 flows through one first energy transfer module 602, then through one second energy transfer module 640, and then through one energy transfer module 642 and then through a single inlet plenum 9 being in fluid communication with at least one packing section 12a, 12b, 12c.

[0300] As shown in this example, each energy transfer module 642, 640, 602 includes a first airflow circuit 504, 544, 604 and a second airflow circuit 506, 542, 606. The first airflow circuit 504, 544, 604 includes an inlet 508, 546, 608 and an outlet 510, 548, 610. The second airflow circuit 506, 542, 606 includes an inlet 512, 552, 612 and an outlet 514, 550, 614. Generally, first airflow circuit 504, 544, 606 and second airflow circuit 506, 542, 606 are fluidly decoupled from each other, such that no gas (e.g., air) flows between the first airflow circuit 504, 544, 604 and the second airflow circuit 506, 542, 606. However, the first airflow circuit 504, 544, 604 and the second airflow circuit 506, 542, 606 (as explained with reference to FIGS 2A and 2B) are in energy communication with each other, such that energy can be transferred between airflows that flow through the respective first airflow circuit 504, 544, 604 and second airflow circuit 506, 542, 606.

[0301] In this example gas-liquid contactor 600 of FIG. 8, each module of the first pair of energy transfer modules 642 is a thermal energy transfer module 642, for example a sensible heat energy transfer module (e.g., the transferred energy is sensible heat). During operation of the gasliquid contactor 600 (and the first pair of energy transfer modules 642), sensible heat from an airflow downstream of the second pair of energy transfer modules 640 (in other words, a CCh-lean airstream 665) is transferred by the first pair of energy transfer modules 642 to the flow of dilute fluid source 1.Attorney Docket No.: 30285-0050W01

[0302] Further, in the example gas-liquid contactor 600, each module of the second pair of energy transfer modules 640 is an enthalpy transfer module (e.g., the transferred energy is enthalpy). During operation of the gas-liquid contactor 600 (and the second pair of energy transfer modules 640), enthalpy or moisture (or both) from the airflow downstream of the third pair of energy transfer modules 602 (the CCh-lean airstream 663) is transferred by the second pair of energy transfer modules 640 to the CCh-rich airstream 551 flowing from the first pair of energy transfer modules 642 whose temperature has been raised by the first pair of energy transfer modules 642 and which (optionally) has been further heated by one or more heaters 620 as described below.

[0303] Further, in the example gas-liquid contactor 600, each module of the third pair of energy transfer module 602 is a thermal energy transfer module, for example a sensible heat energy transfer module (e g., the transferred energy is sensible heat). During operation of the gas-liquid contactor 600 (and the third pair of energy transfer modules 602), sensible heat from an airflow (e.g., a CCh-lean airstream 661) downstream of the at least one packing section 12a, 12b, or 12c is transferred by the third pair of energy transfer modules 602 to an airflow (e.g., a CCh-rich airstream 659) upstream of the at least one packing section 12a, 12b, or 12c.

[0304] As further shown in this example, the at least one heater 620 (e.g., one in each cell side of the dual-cell gas-liquid contactor 600) is positioned in the flow path 8 between one energy transfer module 642 of the first pair and one energy transfer module 640 of the third pair. As shown, each heater 620 (which can be an electric heater, fluid-to-fluid heat exchanger, or other type of heater) is positioned between the outlet 510 of the first pair of energy transfer modules 642 and the inlet 546 of the third pair of energy transfer modules 640. During operation, as described later, the at least one heater 620 heats an airflow that exits the outlet 510 and then (once heated) enters the inlet 546.

[0305] As further shown in this example, at least one basin heater 520 is positioned in the basin 521 (such as a bottom basin) of the gas-liquid contactor 600. The basin 521, as shown, collects the CCh-rich capture solution 523 that flows into the basin 521 from the at least one packing section 12a, 12b, or 12c (resulting from the CCh-capture solution having absorbed CO2 from the dilute fluid source 1). As shown in FIG. 8, the at least one basin heater 520 (which can be an electric heater, fluid-to-fluid heat exchanger, or other type of heater) is positioned to heat the CCh-rich capture solution 523 before at least a portion of the CCh-rich capture solution 523 isAttorney Docket No.: 30285-0050W01 redistributed back to the at least one packing section 12a, 12b, or 12c to further absorb CO2 from the dilute fluid source 1. As shown in this example, a heating supply fluid 561 is flowed to the at least one basin heater 520 (as a fluid-to-fluid heat exchanger), heats the CCh-rich capture solution 523, and then a heating return fluid 563 leaves the basin heater 520. A heat source 531, which, for example, can be a waste heat source from or within the DAC system 800, 900, 1200, 2000, 3000 provides the heat energy to re-heat the heating return fluid 563 and form the heating supply fluid 561.

[0306] In operation of the gas-liquid contactor 600, generally, the at least one fan 11 draws the dilute fluid source 1, such as atmospheric air, into the at least one inlet 4a, 4b and through the first airflow circuit 504 of the first pair of energy transfer modules 642. Simultaneously, the at least one fan 11 flows the CCh-lean airstream 661 from the at least one packing section 12a, 12b, 12c through the second airflow circuit 606 of the third pair of energy transfer modules 602. The CCh-lean airstream 661 transfers sensible heat to a heated CCh-rich airstream 657 to produce a CCh-rich airstream 659 that has a higher temperature compared to the temperature of the CCh-rich airstream 657, and a cooler and / or drier CCh-lean airstream 663.

[0307] The CCh-lean airstream 663 enters the inlet 552 of the second airflow circuit 542 of the second pair of energy transfer modules 640. Through the second pair of energy transfer modules 640, the CCh-lean airstream 663 transfers enthalpy or moisture (or both) to a CCh-rich airstream 551 that has been heated through the first airflow circuit 504 of the first pair of energy transfer modules 642 and / or by the heaters 620. A cooled and drier CCh-lean airstream 665 leaves the outlets 554 of the second airflow circuits 542 of the second pair of energy transfer modules 640 and then enters the inlets 512 of the second airflow circuits 506 of the first pair of energy transfer modules 642. Sensible heat is transferred from the cooled and drier CCh-lean airstream 665 to the dilute fluid source 1 in the first pair of energy transfer modules 642. The heated dilute fluid source 1 leaves the outlets 510 of first airflow circuits 504 of the first pair of energy transfer modules 642 as the CCh-rich airstream 551. CCh-rich airstream 551 can be further heated (to heated CCh-rich airstream 553) by the at least one heater 620 to increase its temperature. By heating the CCh-rich airstream 551 prior to entering the second pair of energy transfer modules 640, more moisture can be transferred from the CCh-lean airstream 663 to the heated CCh-rich airstream 553 (similar to the operation described with reference to FIG. 6). The heated CCh-rich airstream 553 enters the inlets 546 of the first airflow circuits 544 of the second pair of energyAttorney Docket No.: 30285-0050W01 transfer modules 640, where it gains moisture and / or heat and leaves the second pair of energy transfer modules 640 as warmer and higher relative humidity CCh-rich airstream 657.

[0308] Referring still to FIG. 8, as the CCh-rich airstream 657 flows toward the airflow inlet 608 of first airflow circuit 604 of the third pair of energy transfer modules 602, sensible heat is transferred by the third pair of energy transfer modules 602 from the CCh-lean airstream 661 flowing from the at least one packing section 12a, 12b, 12c to produce the CCh-rich airstream 659 with higher temperature and higher relative humidity that is then flowed to the at least one packing section 12a, 12b, 12c.

[0309] Positioning the third set of energy transfer modules 602 upstream of the second set of energy transfer modules 640, relative to a direction of gas flow from the at least one packing section 12a, 12b, or 12c to the outlet 6 of the gas-liquid contactor 600, may help to reduce the duty on the second set of energy transfer modules 640 and may also serve to eliminate drift in the exhaust air 3 flowing from the gas-liquid contactor 600. For example, the third set of energy transfer modules 602 acting as sensible heat transfer modules help to lower the temperature of the CCh-lean airstream 663, which may cause some water vapour entrained in the CCh-lean airstream 663 to condense and collect in the basin 521. By helping to condense out some of the water content in the CCh-lean airstream 663, the third set of energy transfer modules 602 help to reduce the moisture content of the CCh-lean airstream 663 upstream of the second set of energy transfer modules 640, thereby lowering the moisture-transfer duty of the second set of energy transfer modules 640 and reducing an amount of liquid aerosolized particles (e.g., drift or mist) in the exhaust air 3.

[0310] In an example water neutral mode of operation of the gas-liquid contactor 600, the at least one heater 620 may be optional - or may be deactivated if present - should sufficient heat be added to the dilute fluid source 1 by the first set of energy transfer modules 642. For example, operation of the first set of energy transfer modules 642 preserves heat already present in the airstreams through the gas-liquid contactor 600 and minimizes an amount of additional heat needed to be added by the at least one heater 620. As warmer air allows for the absorption of more water (warm air can possess more water vapor - moisture - than cold air), heated CCh-rich airstream 551 can absorb more moisture from CCh-lean airstream 663 in the energy transfer modules 640. Therefore, control of the at least one heater 620 (such as by the flow control system 999) can provide for as-needed or intermittent heat added to heated CC -rich airstream 551 by the at leastAttorney Docket No.: 30285-0050W01 one heater 620 depending on an exit air temperature of the airstream from the outlet (or other criteria, such as relative humidity of exhaust air 3).

[0311] The gas-liquid contactor 600 can be operated in a bulk heating mode of operation. In the bulk heating mode of operation, for example, the basin heater 652 operates to raise a temperature of the CCh-rich capture solution 523. The energy transfer modules 602, 640, 642 of the gas-liquid contactor 600 help to reduce or prevent the evaporative losses described above with reference to FIG. 7 during the bulk heating mode, while still allowing the gas-liquid contactor 600 to benefit from the improved CO2 capture kinetics resulting from the warmed CCh-rich capture solution 523.

[0312] For example, the CCh-lean airstream 661 flowing from the at least one packing section 12a, 12b, or 12c has a high moisture content and / or is saturated with water. As the CO2- lean airstream 661 flows through the third set of energy (sensible heat) transfer modules 602, its temperature is reduced, thereby forming the cooled CCh-lean airstream 663. The cooled CCh-lean airstream 663 still has a high moisture content and is flowed to the second set of energy (moistureenthalpy) transfer modules 640 which transfers some or all of the moisture content to the C Ch-rich airstream 551, thereby forming the increased-moisture content CCh-rich airstream 553 flowing from the second set of energy transfer modules 640 and the drier CCh-lean airstream 665. The energy transfer modules 602, 640, 642 can allow for some or all of the heat and moisture transferred between fluid streams of the gas-liquid contactor 600 to remain in the gas-liquid contactor 600. The energy transfer modules 602, 640, 642 can allow for bulk, excess or waste heat from the DAC system 800, 900, 1200, 2000, 3000 to be employed in the gas-liquid contactor 600 to increase CO2 capture, while minimising or preventing evaporative losses normally associated with contacting warmer liquid streams with cooler gas streams.

[0313] Another example mode of operation of the gas-liquid contactor 600 can be considered a water generation mode, such as described above with reference to FIG. 6. In the water generation mode, for example, the at least one heater 620 can be operated (such as by flow control system 999) so that the moisture content of the exhaust air 3 is less than the moisture content of the CCh-rich airstream 659. Such a moisture transfer represents a generation of water by the gas-liquid contactor 600. The water generated in the water generation mode could be used as make-up water in the gas-liquid contactor 600, or for other purposes of the DAC system 800, 900, 1200, 2000, 3000. In the example water generation mode of operation of the gas-liquidAttorney Docket No.: 30285-0050W01 contactor 600, the at least one heater 620 can be operated (e g., continuously or otherwise) to elevate a temperature of heated CCh-rich airstream 551 as high as practical or possible. By elevating the temperature, the relative humidity of the heated CCh-rich airstream 551 is lowered, thereby allowing the heated CCh-rich airstream 551 to absorb more moisture in the second set of energy transfer modules 640. The resulting CCh-rich airstream 553 (further heated by the at least one heater 620) becomes water-saturated and / or has a higher relative humidity than the exhaust air 3.

[0314] Referring to FIGS. 6 and 8, in implementations where the gas-liquid contactor 400, 600 receives the dilute fluid source 1, such as atmospheric air, with high relative humidity, such as along the Gulf Coast of the United States, the water generation mode can allow for the DAC system 800, 900, 1200, 2000, 3000 to be a water-producing system, in addition to being a CO2- producing system. Stated differently, the water generation mode allows for the gas-liquid contactor 400, 600 to extract the moisture content present in the high relative humidity atmospheric air and employ the extracted moisture for DAC purposes. In implementations where operation of the at least one heater 420, 620 is maximized in this mode of operation, the first set of energy transfer modules 402, 642 (as sensible heat transfer modules) allow for recovering as much of the heat that was added to the airstreams by the at least one heater 420, 620.

[0315] The thermal energy transfer modules 402, 540, 602, 642 described herein as being sensible heat transfer module (e.g., the transferred energy is sensible heat) may also transfer moisture between airflows. Such moisture may be present on portions of the thermal energy transfer modules 402, 540, 602, 642 due to effects such as condensation, such that moisture is transferred by entrainment to the other airflow. This moisture transfer by entrainment, should it occur, is minimal compared to the bulk moisture transfer achieved by the enthalpy transfer modules described herein.

[0316] In example implementations, referring to FIGS. 9 and 10, the energy transfer module 320 can be implemented as an energy transfer belt 320 operatively coupled to the at least one inlet 4 and outlet 6 of the gas-liquid contactor 300 that can transfer thermal energy and / or chemical energy including at least one of sensible heat, latent heat, enthalpy and moisture. The description and one, some, or all of the advantages, and functions of features of the energy transfer modules of the present disclosure, including those discussed or shown in relation to an energyAttorney Docket No.: 30285-0050W01 transfer wheel, apply mutatis mutandis to the energy transfer belt unless indicated otherwise in the following description of the energy transfer belt implementations in relation to FIGS. 9 and 10.[003171 In example implementations, referring to FIG. 9, the energy transfer belt 320 includes a plurality of adjacent energy transfer units 322 operatively connected to one another to form a belt or conveyer-like structure that can be actuated (e.g., via controller 999) to convey the plurality of adjacent energy transfer units 322 across the flow path 8. In example implementations, referring to FIGS. 9 and 10, the energy transfer belt 320 is actuated by an external drive 330 being coupled to the energy transfer belt 320 via, for example, cog or gears 324, to ensure advancement of the energy transfer units 322 across the flow path 8. It is noted that the term “across”, when used in relation to movement, such as advancement, of the energy transfer belt 320, is to be understood as in a direction being substantially transverse / perpendicular to the airflows 1 and 3. Upon operating the at least one fan 11, the dilute fluid source 1 is flowed towards the at least one inlet 4 of the gas liquid contactor 300 and contacts the energy transfer units 322 providing energy transfer channels in an inlet section of the energy transfer belt 320 and defining a first (or inlet) airflow circuit 340. In some example implementations, each energy transfer unit 322 can define an enclosure having perforations giving access to an energy transfer material, the perforations and macro / micro porosity of the energy transfer material forming the energy transfer channels of the present disclosure along which the atmospheric air is flowing. In some example implementations, each energy transfer units 322 includes a sealing component, such as a pair of end sealing gaskets 328, to prevent the incoming gas streams (e.g., the dilute fluid source 1 and the CCh-lean gas stream 5) to bypass the energy transfer channels. The CCh-lean gas stream 7 is flowed towards the outlet 6 of the gas-liquid contactor along the flow path 8 and contacts adjacent energy transfer units 322 providing energy transfer channels located in an outlet section of the energy transfer belt 320, defining a second (or outlet) airflow circuit 342. In example implementations, the plurality of energy transfer units 322 are organized as a loop including a lower belt section 325 and an upper belt section 327, with an end of the lower belt section 325 being continuous with an end of the upper belt section 327 to form the loop. Upon actuation of the energy transfer belt 320 and corresponding translation of the energy transfer units 322, a same energy transfer unit 322 contacts the incoming dilute fluid source 1 or the exhausted CCh-lean gas stream 7 in two stages, including a first stage during which said energy transfer unit 322 is part of the lower belt section 325 and a second stage during which said energy transfer unit 322 is part of the upper belt section 327. UponAttorney Docket No.: 30285-0050W01 actuation of the belt 320, the moving adjacent energy transfer units 322 being part of the inlet airflow circuit 340 can be referred to as inlet energy transfer units 322i. The moving adjacent energy transfer units 322 being part of the outlet airflow circuit of the energy transfer belt 320 can be referred to as outlet energy transfer units 322o. As the energy transfer belt is moving, a same energy transfer unit 322 can be conveyed, for example, from the outlet airflow circuit 342 to the inlet airflow circuit 340 of the energy transfer belt 320, such that an outlet energy transfer unit 322o is converted into an inlet energy transfer unit 322i. As the energy transfer belt 320 further moves, a same inlet energy transfer unit 322i is conveyed across the inlet airflow circuit 340 twice and in opposing directions, such that the same inlet energy transfer unit 322i contacts the flowing dilute fluid source 1 twice to form the CCh-rich gas stream 5. Again, such translation of the energy transfer units, i.e., linear displacement across the flow path, is performed without any mixing of the dilute fluid source 1 and the CCh-lean gas stream 5. As the energy transfer belt 320 further moves, each inlet energy transfer unit 322i is gradually converted back to an outlet energy transfer unit 322o, such that a same outlet energy transfer unit 322o contacts the flowing CCh-lean gas stream 7 to form the exhaust air 3. In other implementations of a dual-cell gas-liquid contactor, two energy transfer belts 320 can be implemented such that the C Ch-lean gas stream 7 is flowed from the outlet plenum 13 into outlet energy transfer units 322o of the two energy transfer belts 320.

[0318] Advantages associated with the energy transfer belt implementation of the energy transfer module may include enhancing the energy transfer surface with respect to the inlet surface of the gas-liquid contactor 300 such that the airflows 1 and 3 cannot bypass the respective inlet and outlet airflow circuits 340, 342 when they match the respective inlet and outlet surfaces of the gas-liquid contactor 300. In addition, the airflows being fed to and coming from the respective inlet plenum and outlet plenum are not affected by a change of section since the belt can fully cover the inlet and outlet of the gas-liquid contactor.

[0319] In this example, there is one energy transfer module 320 being a belt-like structure extending over an outlet plenum 13 and two (absorption) cells, each having an inlet plenum 9 comprising at least one packing section 12a. However, in alternative implementations, the gasliquid contactor 300 can be a single cell gas-liquid contactor, where the dilute fluid source 1 entering via the at least one inlet 4 flows through the inlet airflow circuit 340 and only one inletAttorney Docket No.: 30285-0050W01 plenum 9 and then through the outlet plenum 13 and the outlet airflow circuit 342 of the energy transfer module 320.[003201 In example implementations, referring to FIG. 9, the energy transfer belt 320 includes at least one fluid barrier 326 being provided in a vertical plane and in a transverse orientation with respect to a direction of displacement of the energy transfer units 322 to prevent or reduce fluid communication between the at least one inlet airflow circuits 340 and the outlet airflow circuit 342. For example, referring to the dual cell gas-liquid contactor 300 of FIG. 9, two fluid barriers 326 can be provided perpendicularly to the displacement direction of the energy transfer units 322 and in a vertical plane such that both forwardly and backwardly moving energy transfer units 322 can cross the fluid barriers 326 while avoiding fluid communication between the inlet airflow circuits 340 and the outlet airflow circuit 342.

[0321] In example implementations, referring to FIG. 9, the energy transfer belt 320 can include the plurality of energy transfer units 322 being made of energy transfer material (e.g., a thermal energy transfer material such as a metal). In example implementations, each energy transfer unit 322 of the energy transfer belt 320 can include a thermal energy transfer material and a chemical energy transfer material being provided as a coating (e.g., desiccant coating) that is distributed onto at least a portion of the thermal energy transfer material. For example, each energy transfer unit 322 of the energy transfer belt 320 can include a pair of spaced-apart partitions / flights protruding outwardly from a conveying surface to define the energy transfer units 322 between adjacent partitions. Two adjacent partitions can define a gap therebetween that is sized and shaped to receive or include an energy transfer material (e.g., a chemical energy transfer material such as a desiccant) forming each energy transfer unit 322 of the energy transfer belt 320.

[0322] Advantageously, the plurality of energy transfer units 322 can be accessible and serviceable while the gas-liquid contactor 300 operates. In addition, during the flipping of the plurality of energy transfer units 322 from one side of the belt 320 to the other side of the belt 320, the energy transfer material is turned over, which may extend the lifespan of the material when desiccant is used, as desiccant can be broken up to reduce any caking or fouling that may occur. In example implementations, the energy transfer belt 320 can be operated under vibrations to cause additional movements of the energy transfer unit 322.

[0323] Referring to FIG. 9, the gas-liquid contactor 300 includes a liquid distribution system 120 to supply the CCh-capture solution to the at least one packing section 12a of each cellAttorney Docket No.: 30285-0050W01 of the gas-liquid contactor 300, and a basin 21 (such as a bottom basin) to collect the CCh-rich capture solution 23 that flows into the basin 21 from the at least one packing section 12a (resulting from the CCh-capture solution having absorbed CO2 from the dilute fluid source 1).

[0324] FIG. 9 shows the gas-liquid contactor 300 having a dual-cell configuration and being operated according to a co-current arrangement. In other example implementations, an orientation, a sizing and a number of the at least one energy transfer belt 320 can be adapted to a gas-liquid contactor 300 having a single-cell configuration and / or being operated according to a cross-flow arrangement and / or counter-flow arrangement.

[0325] In example implementations, the gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 of the present disclosure can be part of a CO2 capture system, such as the DAC system 800, 900, 1200, 2000, 3000, that further includes at least one energy transfer module of the present disclosure. In the example implementations of FIGS. 11 and 12, the DAC system 2000, 3000 includes at least one energy transfer module 200 being provided separately from the gasliquid contactor 2100, 3100 with the at least one energy transfer module 200 being fluidly connected to the gas-liquid contactor 2100, 3100 via a duct or conduit system 205, 206 to form at least some of the flow path 8. The dilute fluid source 1, such as atmospheric air, is flowed to an inlet of the flow path that can be defined by the at least one energy transfer module, with the inlet of the flow path being thus separate from the at least one inlet of the gas-liquid contactor. Once energy transfer and CO2 absorption are completed, the resulting exhaust CO2-lean gas stream 3 is flowed from an outlet the flow path, that can be defined by the at least one energy transfer module, with the outlet of the flow path being thus separate from the outlet of the gas-liquid contactor.

[0326] In the illustrated example of FIG. 11, gas-liquid contactor 2100 includes many of the same components as gas-liquid contactor 10, 100, 300, 400, 500, 600, 3100, 5000 and the description of such components applies mutatis mutandis to the same components in FIG. 11. In the illustrated examples of FIG. 11 and 12, the at least one energy transfer module 200 includes many of the same components as the at least one energy transfer module 20, 250, 402, 440, 502, 540, 602, 640, 642 and the description of such components applies mutatis mutandis to the same components in FIGS. 11 and 12. For example, although FIG. 11 show a single-cell co-current gasliquid contactor, the DAC system 2000 can be adapted to include a dual-cell gas-liquid contactor 100 as seen in FIG. 3 or a cross-flow gas-liquid contactor 3100 as seen in FIG. 12. Although FIGS. 11 and 12 show an energy transfer wheel of the present disclosure as part of the DAC system 2000,Attorney Docket No.: 30285-0050W013000, the DAC system 800, 900, 1200, 2000, 3000 can include an energy transfer belt of the present disclosure.[003271 For example, in the implementation of FIG. 11, the at least one energy transfer module 200 is part of the DAC system 2000 to transfer energy (e.g., including at least one of thermal energy and / or chemical energy) between a first airflow (e.g., the dilute fluid source 1) and a second airflow (e.g., the CCh-lean airstream 7). For example, the at least one energy transfer module 200 is the energy transfer wheel 200 and more particularly the enthalpy -moisture wheel 200 of the present disclosure. The energy transfer module 200 is provided separate from the housing 2 of the gas-liquid contactor 2100. To ensure fluid communication between the at least one energy transfer module 200 and the gas-liquid contactor 2100, the DAC system 2000 comprises an interconnecting duct network comprising an inlet interconnecting duct 205 and an outlet interconnecting duct 206. The interconnecting duct network ensures fluid communication between the at least one energy transfer module 200 and the gas-liquid contactor 2100, while preventing fluid communication between the inlet interconnecting duct 205 and the outlet interconnecting duct 206. The fluid barrier 210 of the present disclosure further prevents such fluid communication in the at least one energy transfer wheel 200.

[0328] Referring to FIG. 11, the inlet interconnecting duct 205 is positioned between and fluidly connects the inlet airflow circuit 207 of the energy transfer wheel 200 and the at least one inlet 4 of the gas-liquid contactor 2100. For example, the at least one inlet 4 can be defined by an opening of inlet plenum 9 of the gas-liquid contactor 2100. The outlet interconnecting duct 206 is positioned between and fluidly connects the outlet airflow circuit 208 of the energy transfer wheel 200 and the outlet 6 of the gas-liquid contactor 2100. For example, the outlet 6 can be defined by an opening of the outlet plenum 13 of the gas-liquid contactor 2100. Referring to FIG. 11, the flow path 8 along which the dilute fluid source 1 (e.g., atmospheric air) is converted into the exhaust gas stream 3 (e.g., exhaust air 3) is thus further defined by the interconnecting duct network including the inlet interconnecting duct 205 and the outlet interconnecting duct 206. Optionally, the interconnecting duct network can include a secondary inlet duct 203 guiding the dilute fluid source 1 to the inlet airflow circuit 207 of the energy transfer wheel 200, and a secondary outlet duct 209 guiding exhaust air 3 from the outlet airflow circuit 208 of the energy transfer wheel 200 to the ambient atmosphere.Attorney Docket No.: 30285-0050W01

[0329] In example implementations, at least one fan 1 1 of the present disclosure is provided within the outlet plenum 13 to drive the flow of the dilute fluid source 1 along flow path 8 to cause its reduction / depletion in CO2 and its conversion into the exhaust air 3. Optionally, at least one additional fan can be provided, for example in the inlet interconnecting duct 205 and / or the outlet interconnecting duct 206 to further drive the discussed airflows 1, 5, 7 and 3 through the at least one energy transfer module 200, through the gas-liquid contactor 2100 and back through the energy transfer module 200.

[0330] FIG. 11 shows an implementation of a single-cell gas-liquid contactor 2100. However, the number of energy transfer modules can be tailored to the number of absorption cells of the gas-liquid contactor in the flow path. For example, a dual-cell gas-liquid contactor can be fluidly connected to two separate energy transfer wheels, with the outlet plenum being in fluid communication with an outlet air circuit of each one of the two energy transfer wheels via at least one interconnecting duct.

[0331] Integrating an energy transfer module 20, 200, 250, 402, 440, 502, 540, 602, 640, 642 of the present disclosure into a gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 can be challenging, and providing the energy transfer module 20, 200, 250, 402, 440, 502, 540, 602, 640, 642 separately and away from the gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 can alleviate such challenges.

[0332] Referring to FIG. 12, an additional benefit of providing the at least one energy transfer module separately is that the dilute fluid source 1 can be scrubbed of any mist or vapors by providing the separate gas-liquid contactor 3100 with a downstream wash section along the flow path 8. The addition of the downstream wash section is for example favored when using liquid sorbent having a high vapor pressure as the CO2 capture solution.

[0333] Referring to FIG. 12, the CCh-lean gas stream 7 is passed through one or more sections of wash section packing 131 of the wash section of the gas-liquid contactor 3100 where the CCh-lean gas stream 7 is contacted with a wash water stream 133 to remove or reduce the volatilized components and / or the airborne particles from the CCh-lean gas stream 7. For example, in implementations of the present disclosure where the capture species of the CO2 capture solution 114 includes one or more amine species as defined herein, the wash water stream 133 helps to remove or reduce the volatilized amine components from the CCh-lean gas stream 7. For example, in implementations of the present disclosure where the capture species of the CO2 capture solutionAttorney Docket No.: 30285-0050W01114 includes one or more alkali hydroxides species, the wash water stream 133 helps to remove or reduce the liquid airborne particles from the CCh-lean gas stream 7. For example, in implementations of the present disclosure where the capture species of the CO2 capture solution 114 includes both low volatility and high volatility species, the wash water stream 133 helps to remove or reduce both volatilized components and liquid airborne particles from the CCh-lean gas stream 7. For example, in implementations of the present disclosure where the CCh-lean gas stream 7 includes solid airborne particles, irrespective of the capture species of the CO2 capture solution 114, the wash water stream 133 helps to remove or reduce the solid airborne particles entrained the CCh-lean gas stream 7, as well as any components of the CO2 capture solution 114. Contacting the CCh-lean gas stream 7 with the wash water stream 133 at the interface with the wash section packing 131 can thus scrub the CCh-lean gas stream 7 in order to remove or reduce entrained airborne particles and volatilized components.

[0334] The gas stream 7 that is scrubbed flows from the wash section packing 131 and is referred to as the washed CCh-lean gas stream 15. The washed CCh-lean gas stream 15 can flow through the outlet plenum 13 and through the fan cowling 11 to the outlet interconnecting duct (e g., housing) 206 for further energy transfer with the incoming dilute fluid source 1 in the at least one energy transfer module 200 as described herein. The wash water stream 133 that is spent or used for the scrubbing is referred to as the used wash water stream 135. The used wash water stream 135 is collected in the common bottom basin 124 of FIG. 12. In the configuration where the CO2 capture solution 114 includes a hydroxide, the airborne particles in the CCh-lean gas stream 7 include liquid droplets (e.g., aerosolized droplets) of the CO2 capture solution 114. In this configuration, the CCh-lean gas stream 7 is passed through the one or more sections of wash section packing 131 and is contacted with the wash water stream 133 to remove the liquid airborne particles from the CCh-lean gas stream 7.

[0335] The common bottom basin 124 of FIG. 12 contains a comingled or mixed stream of some of the CCh-rich capture solution 111 and some of the used wash water stream 135 and contains dissolved capture species. This comingled stream is referred to as the liquid stream 141.

[0336] Referring to FIG. 12, at least some of the liquid stream 141 is flowable to the wash water regeneration subsystem 140, which is configured for regenerating the wash water stream 133. The wash water regeneration subsystem 140 is in fluid communication with the common bottom basin 124. The wash water regeneration subsystem 140 is downstream of the commonAttorney Docket No.: 30285-0050W01 bottom basin 124, relative to the flow direction of the liquid stream 141 from the common bottom basin 124. In example implementations described in greater detail below and referring to FIG. 12, the wash water regeneration subsystem 140 is separate from the gas-liquid contactor 3100. The regenerated wash water stream 133 produced by the wash water regeneration subsystem 140 can be flowed to the wash section packing 131 for use in removing the volatilized components and / or the airborne particles from the CCh-lean gas stream 7.

[0337] Referring to FIG. 12, in example implementations, the wash water regeneration subsystem 140 includes a pump 176, a filtration unit 150 and a reverse osmosis (RO) unit 151. The pump 176 is configured to flow the liquid stream 141 from the common bottom basin 124 to the filtration unit 150. In example implementations, the pump 176 is configured to provide enough fluid pressure to flow liquids from the wash water regeneration subsystem 140 to a wash water distribution system such as a wash section top basin. In other implementations, the wash water regeneration subsystem 140 includes one or more pumps, in addition to the pump 176, to flow regenerated wash water 133 to the wash section top basin.

[0338] In the filtration unit 150, the liquid stream 141 is processed to filter or separate solid particles from the CCh-rich capture solution 111 and form a retentate stream 144 which includes the solid particles and a permeate stream 145 which includes the CCh-rich capture solution 111. The retentate stream 144 which includes the solid particles can be further processed. For example, the retentate stream 144 can include desirable solid particles such as carbamic acid solids, which can be sent to the capture solution regeneration subsystem 180, while undesirable non-process elements in the retentate stream 144 are discarded from the DAC system 3000.

[0339] Referring to FIG. 12, the RO unit 151 is located downstream of the filtration unit 150, relative to the flow direction of liquids from the common bottom basin 124 to the the wash section top basin. The RO unit 151 is in fluid communication with the filtration unit 150 and is configured to receive at least some of the permeate stream 145 from the filtration unit 150. Referring to FIG. 12, in example implementations, the pump 176 is a high-pressure RO pump that flows the permeate stream 145 at a relatively high pressure through the RO unit 151. In the RO unit 151, the permeate stream 145 comprising the CO2-rich capture solution 111 is processed to separate water from the CO2 capture species within the CO2-rich capture solution 111. This process results in the formation of an RO retentate stream 146 comprising the CO2-rich capture solution 111 and an RO permeate stream 147 comprising water. In example implementations, theAttorney Docket No.: 30285-0050W01 reverse osmosis unit 151 includes a semi-permeable membrane that allows water to pass through as permeate, effectively concentrating the CO2 capture species in the RO retentate stream 146. One or more membranes of the RO unit can select for and reject ions of the capture species, to produce the RO retentate stream 146 being rich in the capture species, and the RO permeate stream 147 comprising primarily water. In example implementations, the RO unit 151 can be substituted with a nanofi Itrati on (NF) unit 151.

[0340] The water of the RO permeate stream 147 is flowed from the RO unit 151 as the regenerated wash water stream 133 to the wash section packing 131 for reuse in removing the volatilized components and / or the airborne particles from the COz-lean gas stream 7. The pump 176 is used to flow the regenerated wash water stream 133 to the wash section packing 131.

[0341] In example implementations, the RO retentate stream 146 is split into two slip streams 146a and 146b. The first slip stream 146a can be flowed to the common bottom basin 124 which is in fluid communication with the RO unit 151. The second slip stream 146b can flow, directly or indirectly, to the capture solution regeneration subsystem 180 and / or to the at least one capture packing section 12a. This can be achieved by flowing the slip stream 146b to comingle with the liquid stream 141 at a location upstream of the capture solution regeneration subsystem 180, relative to a flow direction of liquids from the common bottom basin 124 to the capture solution regeneration subsystem 180. In example implementations, some of the permeate stream 145 is flowed to the common bottom basin 124. In example implementations, a slipstream of the permeate stream 145 is flowed, directly or indirectly, to the capture solution regeneration subsystem 180 and / or to the at least one packing section 12a. This can be achieved by flowing the slip stream to comingle with the liquid stream 141 at a location upstream of the capture solution regeneration subsystem 180, relative to a flow direction of liquids from the common bottom basin 124 to the capture solution regeneration subsystem 180.

[0342] Referring to FIG. 12, the capture solution regeneration subsystem 180 is in fluid communication with the gas-liquid contactor 3100. The capture solution regeneration subsystem 180 is configured to regenerate the CO2 capture solution 114. A pump 170 in fluid communication with the common bottom basin 124 is used to flow the liquid stream 141 comprising the dissolved capture species and any undissolved solids from the common bottom basin 124 to the capture solution regeneration subsystem 180. In the capture solution regeneration subsystem 180, CO2 is separated from the C Ch-rich capture solution 111 to form a regenerated CO2 capture solution 114,Attorney Docket No.: 30285-0050W01 and a CO2 product stream 125. The regenerated CO2 capture solution 114 is flowed to one or more components of the gas-liquid contactor 3100 for use in capturing CO2 from the dilute fluid source 1, such as atmospheric air. In example implementations, the regenerated CO2 capture solution 114 is flowed to the at least one capture packing section 12a. In example implementations, the regenerated CO2 capture solution 114 is flowed to a capture solution distribution system 120 including a capture section top basin. In example implementations, the regenerated CO2 capture solution 111 is flowed to the common bottom basin 124. In example implementations, the regenerated CO2 capture solution I l l is flowed to one or more distribution points of the capture packing section 12a. Different implementations of the capture solution regeneration subsystem 180 are further described in detail below, including regeneration subsystems 1280, 880, 980.

[0343] In example implementations and referring to FIG. 12, the DAC system 3000 includes a solids sensor 160 and a capture solution control valve 182. The solids sensor 160 and the capture solution control valve 182 are located downstream of the common bottom basin 124, and upstream of the at least one capture packing section 12a, relative to the flow direction of liquid from the common bottom basin 124 back to the at least one capture packing section 12a. The term “downstream,” in this context, refers to the position of the solids sensor 160 and the capture solution control valve 182 relative to the flow of the CCh-rich capture solution 111, where the solids sensor 160 and the capture solution control valve 182 components are located after the common bottom basin 124 along the direction of the flow of CCh-rich capture solution 111 from the bottom basin 124.

[0344] The solids sensor 160 is configured to detect an amount of solid particles in the CCh-rich capture solution 111. For example, when an amine-based capture solution is used, the solids sensor 160 is configured to detect an amount of solids (e.g., carbamic acid solids) in the CCh-rich capture solution 111. Upon detecting that the amount of solid particles is above a threshold, the capture solution control valve 182 is activated to open and a CCh-rich capture solution pump 174 is controlled to flow at least some of the CCh-rich capture solution 111 from the common bottom basin 124 to the capture solution regeneration subsystem 180 for use in regenerating the CO2 capture solution 114. The presence of solid particles above the threshold amount can be an indication that the CCh-rich capture solution I l l is saturated with solid particles formed from reacting CO2 with the capture species of the CO2 capture solution 114. The presence of solid particles above the threshold amount can be an indication that the CCh-rich captureAttorney Docket No.: 30285-0050W01 solution 11 1 includes a high solids content of solid particles formed from reacting CO2 with the capture species of the CO2 capture solution 114.

[0345] When the solids sensor 160 detects that the amount of solid particles is below the threshold, the pump 170 flows the liquid stream 141 comprising the CCh-rich capture solution 111 from the common bottom basin 124 to the capture packing section 12a. The presence of solid particles below the threshold amount can be an indication that the CCh-rich capture solution 111 is below the saturation point of solid particles formed from reacting CO2 with the capture species of the CO2 capture solution 114, such that the CCh-rich capture solution 111 can be recirculated to the capture packing section 12a to continue capturing CO2 from the CCh-rich airstream 5. In example implementations, the CCh-rich capture solution pump 174 is optional, and only the pump 170 can be used to flow at least some of the CCh-rich capture solution 111 from the common bottom basin 124 to either the capture solution regeneration subsystem 180 or to the capture packing section 12a.

[0346] In example implementations and referring to FIG. 12, the DAC system 3000 includes a liquid level sensor 161 and a make-up water control valve 181 in fluid communication with the common bottom basin 124. The liquid level sensor 161 is configured to detect a liquid level in the common bottom basin 124. Upon detecting that the liquid level is below a threshold using the liquid level sensor 161, the make-up water control valve 181 is activated to open and a make-up water pump 172 is controlled to flow make-up water 162 into the common bottom basin 124. When the level of liquid in the common bottom basin 124 detected by the liquid level sensor 161 is below the threshold value, it can be an indication that there is insufficient water circulating or present in the gas-liquid contactor 3100, such that the make-up water 162 needs to be added. In addition to, or separately from, flowing make-up water 162 to the common bottom basin 124, the make-up water pump 172 can flow the make-up water 162 directly to the wash section packing 131. In addition to, or separately from, flowing the make-up water 162 to the common bottom basin 124 and / or to the wash section packing 131, the make-up water pump 172 can flow the makeup water 162 to a location where the make-up water 162 comingles with the RO permeate stream 147 flowing to the wash section packing 131.

[0347] In example implementations and referring to FIG. 12, the DAC system 3000 includes a concentration sensor 163 and a make-up CO2 capture solution control valve 186. The concentration sensor 163 and the make-up CO2 capture solution control valve 186 are locatedAttorney Docket No.: 30285-0050W01 upstream of the capture packing section 12a. The concentration sensor 163 is configured to detect a concentration of a CO2 capture species in the CO2 capture solution 114 flowing into the capture packing section 12a. Upon detecting the concentration of the CO2 capture species in the CO2 capture solution 114 is below a threshold using the concentration sensor 163, the make-up CO2 capture solution control valve 186 is activated to open and a make-up CO2 capture solution pump 178 is controlled to flow the CO2 capture solution 114 into the capture packing section 12a for use in capturing CO2 from the C Ch-rich airstream 5. When the concentration of the CO2 capture species in the CO2 capture solution 114 is below the threshold, it can be an indication that the CO2 capture solution 114 will be less effective at absorbing CO2 from the CC -rich airstream 5, such that it needs to be replenished.

[0348] In example implementations and referring to FIG. 12, the DAC system 3000 includes an emissions sensor 164 and a make-up wash water control valve 184. The emissions sensor 164 functions to detect the concentration or presence of the capture species in a gas flow. For example, and in example implementations, the emissions sensor 164 is located downstream of the wash packing section 131, relative to the flow direction of gas from the wash packing section 131. In such a location, the emissions sensor 164 functions to detect the concentration or presence of the capture species in the washed CCh-lean gas stream 15. In example implementations, the emissions sensor 164 can be located downstream of the capture packing section 12a and located upstream of the wash packing section 131, relative to the flow direction of gas from the capture packing section 12a. In such a location, the emissions sensor 164 functions to detect the concentration or presence of the capture species in the CCh-lean gas stream 7. In yet another configuration, the emissions sensor 164 is located both upstream of the wash packing section 131, and downstream of the wash packing section 131.

[0349] The emissions sensor 164 is configured to detect a concentration of a CO2 capture species at its location. The emissions sensor 164 is communicatively coupled to the make-up wash water control valve 184. Upon detecting the concentration of the CO2 capture species in the monitored gas flow exceeds a threshold, the make-up wash water control valve 184 is activated to open and the pump 176 is controlled to flow the wash water stream 133 to the wash packing section 131, so as to further reduce the volatilized components and / or the airborne particles in the CO2- lean gas stream 7. The presence of the CO2 capture species in the gas flow above the threshold amount can be an indication that the wash packing section 131 is not reducing or eliminating theAttorney Docket No.: 30285-0050W01 volatilized components and / or the airborne particles sufficiently, such that additional wash water 133 may be needed to adequately scrub the CCh-lean gas stream 7.

[0350] Other techniques can be used to prevent or reduce the presence of the CO2 capture species in the gas flow exiting the gas-liquid contactor 3100. For example, one or more of the following non-limiting examples of techniques can be used: the make-up wash water control valve 184 is opened to flow additional wash water 133, the pump 170 is stopped to prevent the creation of additional volatilized components and / or the airborne particles of the CO2 capture solution 114, the fan 11 can be slowed or stopped to prevent volatilized components and / or the airborne particles (such as aerosolized particles) from leaving the gas-liquid contactor 3100. Reference is further made to patent application PCT / US2025 / 034032 entitled “Capturing Carbon Dioxide”, the entire contents of which are incorporated by reference herein.

[0351] Although FIGS. 11 and 12 show a single energy transfer module, the configuration of the DAC system 800, 900, 1200, 2000, 3000 can be adapted to include and operate multiple energy transfer modules and at least one heater separately from the gas-liquid contactor 2100, 3100 such as the multiple energy transfer modules 20, 200, 402, 440, 502, 540, 602, 640, 642 and the at least one heater 420, 620. When operating multiple energy transfer modules, the interconnecting duct network can include at least one additional interconnecting duct to provide a dedicated flow path portion to each incoming airstream. For example, in implementations where the DAC system 800, 900, 1200, 2000, 3000 would include another energy transfer wheel 200 being laterally adjacent to a first energy transfer wheel 200, the interconnecting duct network can include another inlet interconnecting duct and another outlet interconnecting duct.

[0352] While the gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 can be described as having an upper wall 18, 5171 with at least one inlet 4, 103iu, 5103iu and an outlet 6, 103o, 5103o, in example implementations, the gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 does not include an upper wall and the dilute fluid source (e.g., ambient air 1) flows freely into the at least one inlet plenum 9 of the gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 through the open top of the housing 2, 102, 5102 in response to movement of the at least one fan 11, 212, 5112. For example, as seen in FIG. 9, the dilute fluid source 1 can flow into the inlet plenums 9 and through the energy transfer module 320 via an open top of the housing 323.Attorney Docket No.: 30285-0050W01

[0353] In addition, while the gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 can be described as including a bottom basin 110, 2110, 3110, 4110, 5110 in example implementations, the gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 does not include a bottom basin. For example, in example implementations, the CO2 capture solution 114 collected from the packing sections 106, 2106, 3106, 4106, 5106 and entrained CO2 capture solution 114 exiting the CCh-lean gas 7 can be funneled (e.g., by using bottom walls 173, 175, 2173, 2175, 3173, 3175, 4173, 5173) into an open pipe and gravity fed into an external reservoir or tank.

[0354] In example implementations, the energy transfer module 20, 200, 250, 320, 402, 440, 502, 540, 602, 640, 642 can be operated non-continuously. Referring to FIG 9, for example, advancement of the energy transfer belt 320 across the flow path 8 can be periodically stopped to increase a contact time of the energy transfer units 322, 322i, 322o with the inlet airflow 1 and outlet airflow 7 in the respective inlet airflow circuit 340 and outlet airflow circuit 342.

[0355] Although FIGS. 1 and 4-8 show two adjacent energy transfer modules 20, 200, 402, 440, 502, 540, 602, 640, 642, it is noted that the energy transfer modules 20, 200, 250, 320, 402, 440, 502, 540, 602, 640, 642 of the present disclosure can have various configurations and positioning within the housing 102, 2102, 3102, 4102, 5102 in accordance with the various configurations of the gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 to transfer energy from one airflow to another airflow through each energy transfer module 20, 200, 250, 320, 402, 440, 502, 540, 602, 640, 642.

[0356] Definitions and features described in relation to air and airflows entering and exiting the gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 and / or the DAC system 800, 900, 1200, 2000, 3000 of the present disclosure can apply mutatis mutantis to gas streams other than ambient or atmospheric air, including other dilute gas sources as defined herein.

[0357] Referring to FIG. 13, at least one gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 including one or more energy transfer modules 20, 200, 250, 320, 402, 440, 502, 540, 602, 640, 642 as described herein, is part of a direct-air-capture (DAC) system 800, 900, 1200, 2000, 3000 for capturing CO2 directly from atmospheric air, according to one possible and non-limiting example of a use for the gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000. The DAC system 800, 900, 1200, 2000, 3000 includes the one or more energy transfer modules 20, 200, 250, 320, 402, 440, 502, 540, 602, 640, 642 as part of the at least one gas-liquidAttorney Docket No.: 30285-0050W01 contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 or in fluid communication with the at least one gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 in accordance with the various implementations of the present disclosure. The at least one gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 absorb some of the CChfrom the dilute fluid source 1 using the CO2 capture solution 114 to form the CCh-rich capture solution 111. The CO2 capture solution 114 may need to be regenerated from the CCh-rich capture solution 111, which can be carried out in a regeneration system 180, 880, 980,1280 of the DAC system 800, 900, 1200, 2000, 3000. The regeneration system 180, 880, 980,1280 functions to process the CCh-rich capture solution 111 (e.g., spent capture solution) to recover and / or concentrate the CO2 content laden in the CCh-rich capture solution 111.

[0358] Referring to the regeneration subsystem 1280 of FIG. 14, the CCh-laden capture solution 111 flows from the gas-liquid contactor 100 (or 10, 400, 500, or 600) to a pellet reactor 1210 of the DAC system 1200. A slurry of calcium hydroxide 1224 is injected into the pellet reactor 1210. A reaction between the CCh-laden capture solution 111 and the calcium hydroxide 1224 occurs in the pellet reactor. Ca2+reacts with COs2' in the pellet reactor 1210 to form calcium carbonate solids and an aqueous alkaline solution as the CO2 capture solution 114 (such as hydroxide), thereby regenerating the CO2 capture solution 114. For example, potassium carbonate in the CCh-laden capture solution 111 can react with calcium hydroxide to form calcium carbonate and potassium hydroxide, thereby regenerating the CO2 capture solution 114 that includes potassium hydroxide.

[0359] The reaction of the CCh-laden capture solution 111 with Ca(OH)2 causes precipitation of calcium carbonate (CaCCh) onto calcium carbonate particles in the pellet reactor 1210. Further processing of the calcium carbonate solids, including but not limited to fdtering, dewatering or drying, may occur prior to sending the calcium carbonate solids to downstream process units. A stream 1214 of calcium carbonate solids is transported from the pellet reactor 1210 to a calciner 1216 of the DAC system 1200. The calciner 1216 calcines the calcium carbonate of the stream 1214 from the pellet reactor 1210 to produce a stream of gaseous CO2 1218 and a stream of calcium oxide (CaO) 1220, possibly by oxy-combustion of a fuel source in the calciner 1216. The stream of gaseous CO2 1218 is processed for sequestration or other uses, thereby removing some of the CChfrom the CCh-rich airstream 101 processed in the gas-liquid contactor 100 (or 10, 400, 500, or 600). The stream of gaseous CO2 1218, either directly or after processing,Attorney Docket No.: 30285-0050W01 may be provided as a product stream for use as desired, or for export. The stream of calcium oxide (CaO) 1220 is slaked with water in a slaker 1222 of the DAC system 1200 to produce the slurry of calcium hydroxide 1224 that is provided to the pellet reactor 1210. The DAC system 1200 may include multiple gas-liquid contactors 100 (or 10, 400, 500, or 600), where each gas-liquid contactor 100 (or 10, 400, 500, or 600) forms a cell of a train / assembly of gas-liquid contactors 100 (or 10, 400, 500, or 600).

[0360] The regeneration system 1230 can include liquid distribution pipes, solids conveying equipment, fdtration systems, intermediate components like storage vessels, and / or an assembly of components which function cooperatively to regenerate the CO2 capture solution 114. The regeneration system 1230 also includes pumps which flow liquids to and from the regeneration system 1230.

[0361] The stream 1214 of calcium carbonate solids of the DAC system 1200 that is calcined in the calciner 1216 may be produced according to other techniques for capturing CO2 from the CCh-rich airstream 101. For example, on one example implementation, the gas-liquid contactor 100 (or 10, 400, 500, or 600) of the DAC system 1200 uses a liquid sorbent, and a carbonate-forming reactor which receives the CCh-laden capture solution 111 includes one or more reactors similar to those used in the Kraft pulping process to form calcium carbonate solids. In example aspects, the DAC system 1200 is free of a causticization process, and the gas-liquid contactor 100 (or 10, 400, 500, or 600) of the DAC system 1200 uses a liquid sorbent such as a calcium hydroxide slurry and contacts it with air to form the stream 1214 of calcium carbonate solids which are then calcined.

[0362] In example implementations, the CO2 capture solution 114 may be regenerated using a different regeneration system. The regeneration system 1230 may be part of the gas-liquid contactor 10, 100, 400, 500, 600 or separate therefrom. In an example alternate regeneration system, the CCh-laden capture solution 111 may flow to an electrochemical system that includes a cell stack, which may include a set of one or more membranes, and a set of electrodes (see, for example, FIG. 9). The electrochemical system can regenerate the CO2 capture solution 114 from the CCh-laden capture solution 111 by applying an electric potential to an electrolyte including the CCh-laden capture solution 111. The difference in electric potential causes ion exchange, thereby forming the recovered CO2 1218 and regenerating the CO2 capture solution 114.Attorney Docket No.: 30285-0050W01

[0363] In another example implementation of the alternate regeneration system, the CO2- laden capture solution 111 may flow to a thermal stripping column that employs steam to desorb CO2 from the CCh-laden capture solution 111, thereby forming the recovered CO2 stream 1218 and regenerating the CO2 capture solution 114 (e.g., CCh-lean liquid). For example, the DAC system 800 of FIG. 15 includes one or multiple gas-liquid contactor(s) 10, 100, 400, 500, 600 and a regeneration subsystem 880. The regeneration subsystem 880 is configured for regenerating a CO2 capture solution (e.g., the CO2 capture solution 114).

[0364] In implementations where the CO2 capture solution 114 includes an amine capture species, the CO2 from the dilute fluid source 1 reacts with the amine capture species to form the CCh-laden capture solution 111 including carbamates. Non-limiting examples of the amine capture species of the CCh-capture solution 114 include, furan-bis(iminoguanidine) (FuBIG), isophorone diamine (IPDA), a hindered amine group having alkanolamine and alcoholic hydroxyl can be used. Examples of the alkanolamine include monoethanolamine (MEA), diethanolamine, triethanolamine, methyldiethanolamine, diisopropanolamine, and diglycolamine. Examples of the hindered amine having alcoholic hydroxyl include 2-amino-2-m ethyl -1 -propanol (AMP), 2- (ethylamino)-ethanol (EAE), and 2-(methylamino)-ethanol (MAE).

[0365] The regeneration subsystem 880 includes at least a concentrator 805, a heat exchanger 809, and a regeneration reactor 807. The CCh-laden capture solution 111 can include solids (e.g., carbamate solids) and be in the form of a slurry. The slurry is flowed to the concentrator 805, which functions to increase the concentration of the solids by separating solids from liquids. A solids slurry stream 821 is generated by the concentrator 805. The solids slurry stream 821 includes a higher concentration of solids than the concentration of solids in the CO2- laden capture solution 111. At least some of the liquid separated from the CCh-laden capture solution 111 by the concentrator 805 forms a separated liquid stream 823, which can include unreacted CO2 capture solution 114. The separated liquid stream 823 is flowed back to any suitable component or unit of the gas-liquid contactor(s) 10, 100, 400, 500, 600.

[0366] Referring to FIG. 15, the solids slurry stream 821 flows to the heat exchanger 809, where thermal energy from a regenerated, CCh-lean capture solution 811 is transferred to the solids slurry stream 821, as described below. The heated solids slurry stream 821 flows from the heat exchanger 809 to the regeneration reactor 807. The heat exchanger 809 may be considered a preheat heat exchanger that heat integrates a concentrated slurry (e.g., the solids slurry stream 821)Attorney Docket No.: 30285-0050W01 with a higher temperature regenerated capture solution (e.g., the CCh-lean capture solution 81 1). In example implementations, the solids in the heated solids slurry stream 821 are at least partially regenerated in the heat exchanger 809 or downstream thereof, releasing CCh, prior to entering the regeneration reactor 807. In example implementations, the heat exchanger 809 is upstream of the concentrator 805, relative to a flow direction of the CCh-laden capture solution 111 from the gasliquid contactor(s) 10, 100, 400, 500, 600 to the concentrator 805. In such implementations, the heat exchanger 809 functions to transfer thermal energy from the CCh-lean capture solution 811 to the CCh-laden capture solution 111 before it undergoes solid-liquid separation in the concentrator 805. In transferring thermal energy to streams entering the regeneration reactor 807, the heat exchanger 809 helps to reduce the duty of the regeneration reactor 807 in implementations where the regeneration reactor 807 uses heat to regenerate the CCh-laden capture solution 111. In other implementations, the regeneration subsystem 1980 does not have a heat exchanger.

[0367] In implementations where the regeneration reactor 807 is, or includes, a packed column, the heated solids slurry stream 821 flows through packing 803 within the regeneration reactor 807. A regeneration heater 806 supplies a source of heat, such as a stream of heated gas 817 (e.g., steam), which contacts the heated solids slurry stream 821 flowing along the packing 803. In example implementations, the regeneration reactor 807 includes one or more nozzles for flowing the heated solids slurry stream 821 onto the packing 803. In alternate example implementations, the regeneration reactor 807 includes a column with trays instead of, or in addition to, the packing column. In example implementations, the packing 803 is non-structured (e.g., random packing).

[0368] By contacting the heated solids slurry stream 821 and its carbamate solids with the stream of heated gas 817, the CCh-lean capture solution 811 (e.g., regenerated CO2 capture solution 114) is generated and a CO2 gas 819 is desorbed. The CCh-lean capture solution 811 collects at the bottom of the regeneration reactor 807. Referring to FIG. 8, the CCh-lean capture solution 811 is at a relatively high temperature and is flowed to the heat exchanger 809 to transfer at least some of its thermal energy to the solids slurry stream 821 flowing from the concentrator 805, as described above. In implementations where the regeneration subsystem 1980 does not have a heat exchanger, the CCh-lean capture solution 811 is flowed directly to one or more components of the gas-liquid contactor(s) 10, 100, 400, 500, 600 and reused in the gas-liquid contactor(s) 10, 100, 400, 500, 600 for CO2 capture.Attorney Docket No.: 30285-0050W01

[0369] The CO2 gas 819 is released from the regeneration reactor 807 along with water vapor 818 via a gas discharging line. The mixed gas stream (CO2 gas 819 and water vapor 818) flow from the regeneration reactor 807 to a condenser 808. Depending on the capture species of the CO2 capture solution 114, the mixed gas stream can also include volatile amines / organics. The condenser 808 condenses the water vapor 818 (and the volatile amines / organics), forms a water stream 820 (which can have condensable amines / organics), and separates the CC gas 819 from the water stream 820. The CO2 gas 819 is released from the condenser 808 as a CO2 product stream 825. The CO2 product stream 825 can be treated or processed as desired, such as by being compressed. The compressed CO2 product stream 825, either directly or after processing, can be provided for use as desired, or for export. In example implementations, the condensed water stream 820 flows from the condenser 808 to the regeneration heater 806 to be used to generate the stream of heated gas 817 in the regeneration reactor 807. In example implementations, the condensed water stream 820 flows directly to the heat exchanger 809.

[0370] Other configurations for the regeneration reactor 807 are possible. For example, in some configurations, the regeneration reactor 807 does not include a packed column and is thus free of packing. In such a configuration, the regeneration reactor 807 can be, or can include, any one of the following non-limiting examples of reaction vessels: a tubular reactor, a continuous stirred tank reactor (CSTR) in which reagents, reactants, and solvents flow into the reactor while the products of the reaction concurrently exit the vessel, or a fluidized-bed reactor. In implementations where the regeneration reactor 807 is, or includes, a tubular reactor, the tubular reactor can have an internal heating device (e.g., an electric heating element) and / or an external heating device (e.g., a heating jacket), inlet and outlet ports, and a phase separator or other suitable outlet to permit CO2 to degas from the tubular reactor. In implementations where the regeneration reactor 807 is, or includes, a CSTR, the CSTR can have an internal heating device (e.g., an electric heating element) and / or an external heating device (e.g., a heating jacket), a mixing element (such as a rotor and / or baffles), inlet and outlet ports, and a phase separator or other suitable outlet to permit CO2 to degas from the CSTR. In implementations where the regeneration reactor 807 is, or includes, a fluidized-bed reactor, the solids slurry stream 821 can enter the fluidized-bed reactor from a top of the reactor, and a heating medium (e.g., steam) can be heated externally and flowed to the fluidized-bed reactor to fluidize the bed of solids and transfer heat thereto. The fluidized- bed reactor can have a distribution plate or mesh at a bottom thereof to support the solids beingAttorney Docket No.: 30285-0050W01 fluidized. The fluidized-bed reactor can also have inlet and outlet ports, and a phase separator or other suitable outlet to permit CO2 to degas from the fluidized-bed reactor.

[0371] In another example implementation of the alternate regeneration system, the DAC system 900 of FIG. 16 includes regeneration subsystem 980. The regeneration subsystem 980 is configured to regenerate a C Ch-rich sorbent (e.g., the CCh-laden capture solution 111) received from one or multiple gas-liquid contactor(s) 10, 100, 400, 500, 600. The gas-liquid contactor(s) 10, 100, 400, 500, 600 are fluidly coupled to a products generation subsystem 906 via a carbonate separation subsystem 904. The gas-liquid contactor(s) 10, 100, 400, 500, 600provides the CCh- laden capture solution 111 to the carbonate separation subsystem 904.

[0372] The CCh-laden capture solution 111 can be an aqueous mixture comprising primarily carbonate ions, alkaline metal carbonate (e.g., K2CO3, Na2CC ), or a combination thereof. The CCh-laden capture solution 111 can also include other components in smaller amounts, such as hydroxide ions, alkali metal hydroxide (e.g., KOH, NaOH), water, and impurities. For example, the CO2-laden capture solution 111 can comprise between 0.4 M to 6 M K2CO3 and between 1 M to 10 M KOH. In example implementations, the CO2-laden capture solution 111 can comprise an aqueous Na2COa — NaOH mixture. In example implementations, the CO2-laden capture solution 111 can comprise a mixture of K2CO3 and Na2CO3.

[0373] In example implementations, the carbonate separation subsystem 904 can include a caustic evaporator or a crystallizer (or both). In example implementations, the carbonate separation subsystem 904 can include a nanofdtration unit or a crystallizer (or both). The carbonate separation subsystem 904 yields a crystalline carbonate hydrate 914. Crystalline carbonate hydrate 914 can include carbonate sesquihydrate (M2CO3 1.5 H2O) or an anhydrous carbonate. For example, crystalline carbonate hydrate 914 can include potassium carbonate sesquihydrate (K2CO3 1.5 H2O). In example aspects, the crystalline carbonate hydrate 914 can include sodium carbonate decahydrate (Na2CCh lO H2O). In example aspects, the crystalline carbonate hydrate 914 can include potassium sodium carbonate hexahydrate (KNaCCh 6 H2O). In example implementations, the crystalline carbonate hydrate 914 can include a different stoichiometry of water molecules per unit carbonate in the crystalline carbonate (e.g., M2CO3 n H2O where M is an alkali metal and n is an integer or fractional value).

[0374] The products generation subsystem 906 receives the crystalline carbonate hydrate 914. In example implementations, the products generation subsystem 906 includes aAttorney Docket No.: 30285-0050W01 dissolving tank 908 fluidly coupled to an electrochemical cell 910. In example implementations, the products generation subsystem 906 can include a caustic evaporator.

[0375] The dissolving tank 908 can receive crystalline carbonate hydrate 914 from the carbonate separation subsystem 904, a water stream 920 and a brine stream 922. In example implementations, a polished aqueous solution can be used instead of or in addition to the water stream 920. A polished aqueous solution can be substantially free of particulates and dissolved contaminants. The crystalline carbonate hydrate 914 dissolves in water and combines with bicarbonate HCO3 in brine stream 922 to form a feed solution 916. The feed solution 916 can include a bicarbonate HCO3 -rich solution with a mixture of other components such as carbonate and water.

[0376] The electrochemical cell 910 receives the feed solution 916 and a water stream 920. The electrochemical cell 910 yields at least two product streams including a first product stream 926 that comprises a hydroxide (regenerated CO2 capture solution 114) and is returned to the gasliquid contactor(s) 10, 100, 400, 500, 600 for reuse. The second product stream 928 is sent to a flash tank 912 where a gaseous CO2 product stream 924 is partially or fully released from the flash tank 912 and sent to one or more downstream processing units (e.g., compression unit, electroreduction subsystem, carbon products manufacturing system, syngas generation reactor). For further details and alternate implementations, reference is made to the patent application entitled “Systems and methods for capturing carbon dioxide and regenerating a capture solution” and published as U.S. Patent Application Publication No. 2022 / 0362707 Al, the entire contents of which are incorporated by reference herein.

[0377] The regeneration system 180, 880, 980, 1280 can include liquid distribution pipes, solids conveying equipment, filtration systems, intermediate components like storage vessels, and / or an assembly of components which function cooperatively to regenerate the CO2 capture solution 114. The regeneration system 180, 880, 980, 1280 also includes pumps which flow liquids to and from the regeneration system 180, 880, 980, 1280. The regeneration system 180, 880, 980, 1280 can be part of the gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 or separate therefrom.

[0378] In example implementations, the gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 may include, or be fluidly coupled to, devices for managing liquid level in the gas-liquid contactor 10, 100, 400, 500, 600. These devices may include, but are not limited to,Attorney Docket No.: 30285-0050W01 evaporators to reduce liquid levels and / or maintain concentrations of the CO2 capture solution 114. These devices may include, but are not limited to, water make-up tanks or sources to manage liquid levels and / or maintain concentrations of the CO2 capture solution 114.

[0379] In example implementations, the DAC system 800, 900, 1200, 2000, 3000 may include multiple gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000. In example implementations, the DAC system 800, 900, 1200, 2000, 3000 includes multiple gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000arranged adjacent each other to form an array or a train of gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000. The DAC system 800, 900, 1200, 2000, 3000 may include multiple arrays or trains of gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000. More particularly, each gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 can be grouped together with one or more other gasliquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 to provide the DAC system 800, 900, 1200, 2000, 3000 with one or more wall(s), array(s) or train(s), where each wall, array or train has multiple gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000.

[0380] For example, referring to FIGS. 17 and 18, multiple gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 are arranged next to one another to form a contactor wall 1502. The number of gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 composing the contactor wall 1502 may vary (as represented by the ellipsis symbol “[...]” in FIG. 17). The contactor wall 1502 may include a large number of gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 for example between 10 and 100 gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000. In example implementations, the number of gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 in the contactor wall 1502 is greater than 1,000. The number of gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 in the contactor wall 1502 may be determined based on a variety of factors, such as a plume of CCh-lean gas 105 generated by the contactor wall 1502 during operation of the gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000. The contactor wall 1502 extends along its own wall axis 1509. The wall axis 1509 extends along a direction that is perpendicular to the packing depth 106D ofthe gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000, and perpendicular to the packing LTD 106L of the gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000.Attorney Docket No.: 30285-0050W01

[0381] In implementations where the gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 are positioned (e.g., directly) adjacent each other, and referring to FIG. 17, they may be abutted along a dividing wall 1525 which fluidly separates components of one gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 from an adjacent gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000. The dividing wall 1525 helps to ensure that the CO2- laden air 101 flowing through the one or more airflow inlets 1031 of a gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 flows through the packing section(s) of that gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 rather than into an adjacent gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000. The dividing walls 1525 extend in an upright or vertical direction, and along a direction parallel to the packing depth 106D. In example implementations, the vertical extent of one or more of the dividing walls 1525 begins at, or below, the liquid level in the bottom basin 110. This configuration of the dividing walls 1525 can help to minimise or eliminate air bypassing the dividing walls 1525. The plenum 108 of each gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 is separated from the plenum 108 of an adjacent gas-liquid contactor 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 by one or more dividing walls 1525. At least some of the dividing walls 1525 are internal to the contactor wall 1502. Each dividing wall 1525 forms a barrier to airflow between the adjacent plenums 108 delimited by that dividing wall 1525, so as to prevent air from flowing between the plenums 108. The dividing walls 1525 may allow for multiple gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 to remain operational if one of the gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 or its fan 121 is deactivated. The dividing walls 1525 of FIG. 17 are internal to the contactor wall 1502, and it will be appreciated that the contactor wall 1502 can have externally-applied dividing walls 1525 at opposite longitudinal ends of the contactor wall 1502. The plenums 108 are arranged adjacent each other along the length of the contactor wall 1502 defined along the wall axis 1509. In other implementations, the contactor wall 1502 includes a single plenum 108 that is continuous along its length defined parallel to the wall axis 1509, such that the contactor wall 1502 is free of internal dividing walls 1525. In other implementations, the contactor wall 1502 includes multiple plenums 108 delineated by the dividing walls 1525, where two or more gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 of the contactor wall 1502 share a common plenum 108. In example implementations, the dividing walls 1525 include doors or closeable openings, to provide access to the interior 113 of adjacent gas-liquidAttorney Docket No.: 30285-0050W01 contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000. In example implementations, and referring to FIG. 17, the contactor wall 1502 includes multiple plenums 108, where each gas-liquid contactor 10, 100, 300, 400, 500 forming the contactor wall 1502 has one plenum 108. Each plenum 108 is separated from an adjacent plenum 108 by one or more dividing walls 1525. In the example implementation of FIG. 17, each dividing wall 1525 shown is located between two fan stacks 107 and forms a barrier to airflow between two plenums 108 delimited by that dividing wall 1525, where each plenum 108 is in fluid communication with a respective one of the fan stacks 107.

[0382] The contactor wall 1502 can be part of the DAC system 800, 900, 1200, 2000, 3000.Referring to FIG. 18, each DAC system 800, 900, 1200, 2000, 3000 can include multiple contactor walls 1502 arranged on a plot of land 1505. Each contactor wall 1502 is spaced apart from another contactor wall 1502. In this disclosure, the terms “train”, “array” and “wall” may be used interchangeably. The DAC system 800, 900, 1200, 2000, 3000 of FIG. 18 is shown with multiple contactor walls 1502 for the purposes of illustration. The DAC system 800, 900, 1200, 2000, 3000 can alternatively have only one contactor wall 1502. Referring to FIG. 18, the DAC system 800, 900, 1200, 2000, 3000 includes a regeneration system 180, 880, 980, 1280, such as one or more of those described above, in fluid communication with the contactor walls 1502. The regeneration system 180, 880, 980, 1280 functions to regenerate the CCh-rich sorbent (e.g., the CCh-laden capture solution 111) received from the contactor walls 1502, or from other componentry that treats the CCh-laden capture solution 111 from the contactor walls 1502. The regeneration system 180, 880, 980, 1280 forms a regenerated sorbent (e.g., the regenerated CO2 capture solution 114) that is conveyed back to the contactor walls 1502. The regeneration system 180, 880, 980, 1280 can also function to release CO2 from the CCE-rich sorbent, to produce the CO2 product stream. In example implementations, and referring to FIG. 18, each contactor wall 1502 has a single or common bottom basin 21. In such implementations, the bottom basin 21 of each contactor wall 1502 is in fluid communication with the regeneration system 180, 880, 980, 1280. In example implementations, the process streams from the bottom basin 21 of a contactor wall 1502 flows, or is flowed, to the bottom basin 21 of another contactor wall 1502.

[0383] FIGS. 19 and 20 are flowcharts that illustrate example methods according to the present disclosure. FIG. 19 shows a flowchart that describes an example method 1000 for capturing carbon dioxide (CO2) from atmospheric air. In example aspects, method 1000 can beAttorney Docket No.: 30285-0050W01 performed by one or more gas-liquid contactor, such as gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 disclosed herein, used for capturing CO2 from a dilute fluid source, such as atmospheric air. Method 1000 can begin at step 1002, which includes flowing atmospheric air into an inlet of a flow path that can be defined at least in part by a gas-liquid contactor and / or at least one energy transfer module, such as energy transfer modules 20, 200, 250, 320, 402, 440, 502, 540, 602, 640, 642. For example, the atmospheric air is flowed to the at least one inlet of the gas-liquid contactor and along the flow path. Method 1000 can continue at step 1004, which includes flowing the atmospheric air along a gas-liquid interface. Method 1000 can continue at step 1006, which includes flowing a CO2 capture solution along the gas-liquid interface to absorb CO2 from the atmospheric air into the CO2 capture solution and to form a CCh-lean gas stream. Method 1000 includes step 1008, which includes transferring energy between the CCh-lean gas stream and the atmospheric air with at least one energy transfer module positioned in the flow path. For example, transferring energy between the CCh-lean gas stream and the atmospheric air includes transferring energy from the at least one energy transfer module to the atmospheric air to form a C Ch-rich gas stream in the flow path, and transferring energy from the CCh-lean gas stream to the at least one energy transfer module to form an exhaust CCh-lean gas stream. It is noted that steps related to transferring energy to and from the at least one energy transfer module are dependent on one another to complete the overall transfer of energy between the atmospheric air and the CC -lean gas stream. Method 1000 can continue at step 1010, which includes flowing the exhaust CCh-lean gas stream from an outlet the flow path. In example implementations, the outlet of the flow path is or comprises the at least one outlet of the gas-liquid contactor, such as gasliquid contactor 10.

[0384] In example implementations, the outlet of the flow path is or comprises at least one outlet duct of the energy transfer module, such as energy transfer module 200. In example implementations, the method 1000 can include moving the at least one energy transfer module between the inlet of the flow path and the outlet of the flow path to transfer the energy between the CCh-lean gas stream and the flow of atmospheric air through the at least one energy transfer module being positioned in the flow path. For example, moving the at least one energy transfer module between the inlet of the flow path and the outlet of the flow path includes rotating the at least one energy transfer module about an axis that has a vertical orientation and extends through a radial center of the at least one energy transfer module. In another example, moving the at leastAttorney Docket No.: 30285-0050W01 one energy transfer module between the inlet of the flow path and the outlet of the flow path comprising translating the at least one energy transfer module across the flow path, i.e., linearly displacing the at least one energy transfer module across the flow path, in a first direction from the inlet to the outlet of the flow path to contact the flow of atmospheric air and in a second direction from the outlet to the inlet of the flow path to contact the C Ch-lean gas stream, such as translating the energy transfer units 322 of the energy transfer belt 320.

[0385] FIG. 20 shows a flowchart that describes another example method 1020 for capturing carbon dioxide (CO2) from atmospheric air. In example aspects, method 1020 can be performed by one or more gas-liquid contactor used for capturing CO2 from atmospheric air, such as gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 disclosed herein. Method 1020 can begin at step 1022, which includes flowing atmospheric air through an inlet plenum along a first direction. Method 1020 can continue at step 1024, which includes flowing the atmospheric air along a gas-liquid interface. Method 1020 can continue at step 1026, which includes flowing a CO2 capture solution along the gas-liquid interface to absorb CO2 from the atmospheric air into the CO2 capture solution and to form a CCh-lean gas stream. Method 1020 can continue at step 1028, which includes flowing the CCh-lean gas stream through an outlet plenum along a second direction opposite to the first direction. Method 1020 can continue at step 1030, which includes rotating at least one transfer wheel between the inlet plenum and the outlet plenum to transfer energy, e.g., at least one of moisture or thermal energy, between the CCh-lean gas stream and the atmospheric air.

[0386] FIG. 22 is a schematic diagram of a control system (or controller) 1300 for a gasliquid contactor, such as gas-liquid contactors 10, 100, 300, 400, 500, 600, 2100, 3100, 5000 disclosed herein. The system 1300 can be used for the operations described in association with any of the computer-implemented methods described previou...

Claims

Attorney Docket No.: 30285-0050W01WHAT IS CLAIMED IS:

1. A gas-liquid contactor for capturing carbon dioxide (CO2) from atmospheric air, the gas-liquid contactor comprising: at least one inlet; at least one outlet spaced apart from the at least one inlet; a gas-liquid interface positioned between the at least one inlet and the at least one outlet; a liquid distribution system configured to flow a CO2 capture solution along the gas-liquid interface; at least one fan configured to flow atmospheric air along a flow path from the at least one inlet, along the gas-liquid interface, and to the at least one outlet, to contact the atmospheric air with the CO2 capture solution, thereby absorbing CO2 from the atmospheric air into the CO2 capture solution to form a CCh-lean gas stream flowable through the at least one outlet; and at least one energy transfer module positioned in the flow path, the at least one energy transfer module comprising a plurality of energy transfer channels configured to transfer energy between the CCf-lean gas stream and the flow of atmospheric air, the plurality of energy transfer channels defining: a first airflow circuit that comprises a first airflow inlet positioned to receive the flow of atmospheric air from the at least one inlet and a first airflow outlet fluidly coupled to the first airflow inlet; and a second airflow circuit fluidly separated from the first airflow circuit and comprising a second airflow inlet and a second airflow outlet fluidly coupled to the second airflow inlet and positioned to exhaust the CCh-lean gas stream to the at least one outlet.

2. The gas-liquid contactor of claim 1 , wherein the at least one energy transfer module comprises at least one enthalpy transfer module, and the plurality of energy transfer channels are configured to transfer enthalpy from the CCh-lean gas stream to the flow of atmospheric air.

3. The gas-liquid contactor of either one of claims 1 or 2, wherein the transferred energy comprises: moisture transferred from the CCh-lean gas stream to the flow of atmospheric air; and a heat of absorption from the plurality of energy transfer channels to the flow of atmospheric air.Attorney Docket No.: 30285-0050W014. The gas-liquid contactor of either one of claims 2 or 3, wherein: the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first dry bulb temperature and output a CCh-rich gas stream from the first airflow outlet at a second dry bulb temperature greater than the first dry bulb temperature; and the second airflow circuit is configured to receive the CCh-lean gas stream into the second airflow inlet at a third dry bulb temperature and output an exhaust CCh-lean gas stream from the second airflow outlet at a fourth dry bulb temperature less than the third dry bulb temperature.

5. The gas-liquid contactor of any one of claims 2-4, wherein: the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first relative humidity and output the flow of atmospheric air from the first airflow outlet at a second relative humidity greater than the first relative humidity; and the second airflow circuit is configured to receive the CCh-lean gas stream through the second airflow inlet at a third relative humidity and output the C Ch-lean gas stream from the second airflow outlet at a fourth relative humidity less than the third relative humidity.

6. The gas-liquid contactor of claim 1, wherein the at least one energy transfer module comprises: a first energy transfer module positioned in the flow path, the first energy transfer module comprising the first airflow circuit, the second airflow circuit, and the plurality of energy transfer channels comprise a first plurality of energy transfer channels; and a second energy transfer module positioned in the flow path, the second energy transfer module comprising a second plurality of energy transfer channels configured to transfer energy between the CCh-lean gas stream and the flow of atmospheric air, the second plurality of energy transfer channels defining: a third airflow circuit that comprises a third airflow inlet positioned to receive the flow of atmospheric air from the first airflow outlet and a third airflow outlet fluidly coupled to the third airflow inlet; and a fourth airflow circuit that comprises a fourth airflow inlet and a fourth airflow outlet fluidly coupled to the fourth airflow inlet and positioned to exhaust the CCh-lean gas stream to the second airflow inlet.Attorney Docket No.: 30285-0050W017. The gas-liquid contactor of claim 6, wherein the first energy transfer module comprises a thermal energy transfer module, and the second energy transfer module comprises a chemical energy transfer module.

8. The gas-liquid contactor of either one of claims 6 or 7, wherein the first plurality of energy transfer circuits are configured to transfer sensible heat from the CCh-lean gas stream to the flow of atmospheric air; and the second plurality of energy transfer circuits are configured to transfer moisture from the CCh-lean gas stream to the flow of atmospheric air.

9. The gas-liquid contactor of claim 8, wherein the transferred enthalpy comprises: moisture transferred from the CCh-lean gas stream to the flow of atmospheric air; and a heat of absorption from the second plurality of energy transfer channels to the flow of atmospheric air.

10. The gas-liquid contactor of any one of claims 6-9, comprising at least one heater positioned between the first airflow outlet and the third airflow inlet, the at least one heater configured to heat the flow of atmospheric air from the first airflow outlet to the third airflow inlet.

11. The gas-liquid contactor of claim 10, wherein: the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first relative humidity, and the third airflow circuit is configured to output the flow of atmospheric air from the third airflow outlet at a second relative humidity greater than the first relative humidity; the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first temperature and output the flow of atmospheric air from the first airflow outlet at a second temperature greater than the first temperature; the fourth airflow circuit is configured to receive the CCh-lean gas stream through the fourth airflow inlet at a third relative humidity, and the second airflow circuit is configured to output the CCh-lean gas stream from the second airflow outlet at a fourth relative humidity less than the third relative humidity; and the fourth airflow circuit is configured to receive the CCh-lean gas stream through the fourth airflow inlet at a third temperature, and the second airflow circuit is configured to output the CCh-lean gas stream exits the second airflow outlet at a fourth temperature less than the thirdAttorney Docket No.: 30285-0050W01 temperature.

12. The gas-liquid contactor of claim 11, comprising a control system communicably coupled to the at least one heater and configured to perform operations comprising: controlling the at least one heater to add heat to the flow of atmospheric air between the first airflow outlet and the third airflow inlet such that the fourth relative humidity is less than the first relative humidity.

13. The gas-liquid contactor of claim 6, wherein the first energy transfer module comprises a chemical energy transfer module, and the second energy transfer module comprises a thermal energy transfer module.

14. The gas-liquid contactor of claim 13, wherein the first plurality of energy transfer channels are configured to transfer moisture from the CCh-lean gas stream to the flow of atmospheric air; and the second plurality of energy transfer channels are configured to transfer sensible heat from the CCh-lean gas stream to the flow of atmospheric air.

15. The gas-liquid contactor of either one of claims 13 or 14, wherein the transferred energy comprises: moisture transferred from the CCh-lean gas stream to the flow of atmospheric air; and a heat of absorption from the first plurality of energy transfer channels to the flow of atmospheric air.

16. The gas-liquid contactor of any one of claims 13-15, comprising at least one heater positioned within a volume of the CO2 capture solution and configured to heat the volume of the CO2 capture solution.

17. The gas-liquid contactor of claim 16, comprising a basin configured to collect the CO2 capture solution from the gas-liquid interface, the at least one heater being positioned within the basin.

18. The gas-liquid contactor of any one of claims 13-17, wherein: the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first relative humidity, and the third airflow circuit is configured to output theAttorney Docket No.: 30285-0050W01 flow of atmospheric air from the third airflow outlet at a second relative humidity greater than the first relative humidity; the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first temperature, and the third airflow circuit is configured to output the flow of atmospheric air from the third airflow outlet at a second temperature greater than the first temperature; the fourth airflow circuit is configured to receive the CCh-lean gas stream through the fourth airflow inlet at a third relative humidity, and the second airflow circuit is configured to output the CCh-lean gas stream from the second airflow outlet at a fourth relative humidity less than the third relative humidity; and the fourth airflow circuit is configured to receive the CCh-lean gas stream enters the fourth airflow inlet at a third temperature and output the CCh-lean gas stream from the fourth airflow outlet at a fourth temperature less than the third temperature.

19. The gas-liquid contactor of claim 13, wherein the at least one energy transfer module comprises: a third energy transfer module positioned in the flow path, the third energy transfer module comprising a third plurality of energy transfer channels configured to transfer energy between the CCh-lean gas stream and the flow of atmospheric air, the third plurality of energy transfer channels defining: a fifth airflow circuit that comprises a fifth airflow inlet positioned to receive the flow of atmospheric air from the third airflow outlet and a fifth airflow outlet fluidly coupled to the fifth airflow inlet; and a sixth airflow circuit that comprises a sixth airflow inlet and a sixth airflow outlet fluidly coupled to the sixth airflow inlet and positioned to exhaust the CCh-lean gas stream to the fourth airflow inlet.

20. The gas-liquid contactor of claim 19, wherein the third energy transfer module comprises a thermal energy transfer module.

21. The gas-liquid contactor of either one of claims 19 or 20, wherein the third plurality of energy transfer channels are configured to transfer sensible heat from the CCh-lean gas streamAttorney Docket No.: 30285-0050W01 to the flow of atmospheric air.

22. The gas-liquid contactor of any one of claims 19-21, comprising at least one heater positioned between the first airflow outlet and the third airflow inlet, the at least one heater configured to heat the flow of atmospheric air from the first airflow outlet to the third airflow inlet.

23. The gas-liquid contactor of any one of claims 19 to 22, comprising at least one basin heater positioned within a basin configured to collect the CO2 capture solution from the gasliquid interface, the at least one basin heater configured to heat a volume of the CO2 capture solution.

24. The gas-liquid contactor of claim 23, wherein: the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first relative humidity, and the third airflow circuit is configured to output the flow of atmospheric air from the third airflow outlet at a second relative humidity greater than the first relative humidity; the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first temperature, and the third airflow circuit is configured to output the flow of atmospheric air from the third airflow outlet at a second temperature greater than the first temperature; the sixth airflow circuit is configured to receive the CCh-lean gas stream through the sixth airflow inlet at a third relative humidity, and the second airflow circuit is configured to output the CO2-lean gas stream from the second airflow outlet at a fourth relative humidity less than the third relative humidity; and the sixth airflow circuit is configured to receive the CCh-lean gas stream through the sixth airflow inlet at a third temperature, and the second airflow circuit is configured to output the CO2- lean gas stream exits the second airflow outlet at a fourth temperature less than the third temperature.

25. The gas-liquid contactor of claim 24, comprising a control system communicably coupled to the at least one heater and configured to perform operations comprising: controlling the at least one heater to add heat to the flow of atmospheric air between the third airflow outlet and the fifth airflow inlet such that the fourth relative humidity is less than theAttorney Docket No.: 30285-0050W01 first relative humidity.

26. The gas-liquid contactor of any one of claims 1 to 25, wherein adjacent energy transfer channels of the plurality of energy transfer channels are annular airflow channels circumscribing a radial center.

27. The gas-liquid contactor of claim 26, wherein the annular airflow channels are defined by a plurality of annular sheets.

28. The gas-liquid contactor of claim 27, wherein the plurality of annular sheets comprises an energy transfer material being configured to transfer at least one of thermal energy or chemical energy.

29. The gas-liquid contactor of claim 28, wherein the energy transfer material is a coating on at least one annular sheet of the plurality of annular sheets.

30. The gas-liquid contactor of any one of claims 1-29, wherein the at least one energy transfer module comprises a thermal wheel that defines a wheel axis having a vertical orientation, the thermal wheel configured to rotate about the wheel axis.

31. The gas-liquid contactor of any one of claims 1-29, wherein: the at least one energy transfer module comprises a thermal wheel that defines a wheel axis having a vertical orientation, the thermal wheel configured to rotate about the wheel axis, and the thermal wheel comprises a plurality of annular sheets being concentric about the wheel axis, each annular sheet of the plurality of annular sheets spaced apart from another annular sheet of the plurality of annular sheets in a direction radial to the wheel axis, each energy transfer circuit of the plurality of energy transfer circuits comprising a circumferential air passage defined between adjacent annular sheets of the plurality of annular sheets.

32. The gas-liquid contactor of claim 31, wherein at least one annular sheet of the plurality of annular sheets comprises corrugated metal.

33. The gas-liquid contactor of either one of claims 31 or 32, wherein the plurality of annular sheets comprises a desiccant coating.Attorney Docket No.: 30285-0050W0134. The gas-liquid contactor of any one of claims 1 to 25, wherein adjacent energy transfer channels of the plurality of energy transfer channels are defined by a plurality of adjacent energy transfer units operatively connected to one another to form a belt-like structure being translatable across the flow path.

35. The gas-liquid contactor of claim 34, comprising an external drive to actuate translation of the plurality of adjacent energy transfer units across the flow path.

36. The gas-liquid contactor of claim 34 or 35, wherein the plurality of energy transfer units form a loop having an upper belt section and a lower belt section, and each energy transfer unit of the plurality of energy transfer units is translated across the flow path a first time in a first direction when part of the upper belt section and a second time in a second direction when part of the lower belt section, the second direction being the opposite of the first direction.

37. The gas-liquid contactor of any one of claims 34 to 36, wherein the plurality of energy transfer units comprises: a plurality of inlet energy transfer units comprising the energy transfer channels defining the first airflow circuit receiving the flow of atmospheric air; and a plurality of outlet energy transfer units comprising the energy transfer channels defining the second airflow circuit receiving the CCh-lean gas stream.

38. The gas-liquid contactor of claim 37, wherein the first airflow circuit extends over an entire surface of the at least one inlet, and the second airflow circuit extends over an entire surface of the at least one outlet.

39. The gas-liquid contactor of any one of claims 34 to 38, wherein each energy transfer unit defines a gap or an enclosure that is sized and shaped to receive an energy transfer material, the gap or the enclosure of the energy transfer units configured to provide the plurality of energy transfer channels.

40. The gas-liquid contactor of any one of claims 1 to 39, wherein the at least one inlet comprises at least one vertical inlet, and the at least one outlet comprises at least one vertical outlet spaced apart from the at least one vertical inlet, and the at least one energy transfer module is positioned to intersect the flow path in the at least one vertical inlet and the at least one verticalAttorney Docket No.: 30285-0050W01 outlet.

41. The gas-liquid contactor of any one of claims 1 to 39, wherein the at least one inlet comprises at least one vertical inlet, and the at least one outlet comprises at least one vertical outlet spaced apart from the at least one vertical inlet and separated by the gas-liquid interface, and the at least one energy transfer module is positioned to intersect the flow path in the at least one vertical inlet and the at least one vertical outlet.

42. The gas-liquid contactor of any one of claims 1 to 41, wherein the gas-liquid interface is configured to contact the atmospheric air with the CO2 capture solution in a cross-flow arrangement, a co-current flow arrangement, or a counter-current flow arrangement.

43. The gas-liquid contactor of any one of claims 1 to 42, wherein the gas-liquid interface comprises at least one packing.

44. A method for capturing carbon dioxide (CO2) from atmospheric air, the method comprising: flowing the atmospheric air into an inlet of a flow path comprising at least one energy transfer module; transferring energy from the at least one energy transfer module to the atmospheric air to form a CCh-rich gas stream in the flow path; flowing the CCh-rich gas stream along a gas-liquid interface in the flow path; flowing a CO2 capture solution along the gas-liquid interface to absorb CO2 from the CO2- rich gas stream into the CO2 capture solution and to form a CCh-lean gas stream; transferring energy from the CC -lean gas stream to the at least one energy transfer module to form an exhaust CCh-lean gas stream; and flowing the exhaust CCh-lean gas stream from an outlet the flow path.

45. The method of claim 44, wherein transferring energy from the at least one energy transfer module to the atmospheric air or transferring energy from the CC -lean gas stream to the at least one energy transfer module comprises transferring at least one of thermal energy or chemical energy.Attorney Docket No.: 30285-0050W0146. The method of claim 45, wherein transferring energy from the at least one energy transfer module to the atmospheric air or transferring energy from the CCh-lean gas stream to the at least one energy transfer module comprises transferring enthalpy.

47. The method of either one of claims 45 or 46, wherein transferring energy from the at least one energy transfer module to the atmospheric air or transferring energy from the CO2- lean gas stream to the at least one energy transfer module comprises: transferring moisture from the CCh-lean gas stream to the flow of atmospheric air; and transferring a heat of absorption from the at least one energy transfer module to the flow of atmospheric air.

48. The method of any one of claims 44-47, comprising: flowing the atmospheric air into the at least one energy transfer module at a first dry bulb temperature; flowing the CCh-rich gas stream out of the at least one energy transfer module at a second dry bulb temperature greater than the first dry bulb temperature; and flowing the CCh-lean gas stream into the at least one energy transfer module at a third dry bulb temperature; and flowing the exhaust CCh-lean gas stream out of the at least one energy transfer module at a fourth dry bulb temperature less than the third dry bulb temperature.

49. The method of any one of claims 44-48, comprising: flowing the atmospheric air into the at least one energy transfer module at a first relative humidity; flowing the CCh-rich gas stream out of the at least one energy transfer module at a second relative humidity greater than the first relative humidity; flowing the CCh-lean gas stream into the at least one energy transfer module at a third relative humidity; and flowing the exhaust CCh-lean gas stream out of the at least one energy transfer module at a fourth relative humidity less than the third relative humidity.Attorney Docket No.: 30285-0050W0150. The method of any one of claims 44-49, wherein the at least one energy transfer module comprises a first energy transfer module positioned in the flow path and a second energy transfer module positioned in the flow path in fluid communication with the first energy transfer module.

51. The method of claim 50, wherein transferring energy from the at least one energy transfer module to the atmospheric air or transferring energy from the CCh-lean gas stream to the at least one energy transfer module comprises: transferring sensible heat from the CC -lean gas stream to the flow of atmospheric air with the first energy transfer module.

52. The method of claim 51, wherein transferring energy from the at least one energy transfer module to the atmospheric air or transferring energy from the CCh-lean gas stream to the at least one energy transfer module comprises: transferring moisture from the CC -lean gas stream to the flow of atmospheric air with the second energy transfer module.

53. The method of any one of claims 50-52, wherein transferring energy from the at least one energy transfer module to the atmospheric air or transferring energy from the CC -lean gas stream to the at least one energy transfer module comprises: transferring moisture from the CCh-lean gas stream to the flow of atmospheric air by the first energy transfer module; and transferring a heat of absorption from the second energy transfer module to the flow of atmospheric air.

54. The method of any one of claims 50-53, comprising heating the flow of atmospheric air between the first and second energy transfer modules with at least one heater positioned along the flow path.

55. The method of claim 54, comprising: flowing the atmospheric air into the first energy transfer module at a first relative humidity; flowing the CCh-rich gas stream out of the second energy transfer module at a second relative humidity greater than the first relative humidity;Attorney Docket No.: 30285-0050W01 flowing the atmospheric air into the first energy transfer module at a first temperature; flowing the CCh-rich gas stream out of the second energy transfer module at a second temperature greater than the first temperature; flowing the CCh-lean gas stream into the second energy transfer module at a third relative humidity; flowing the exhaust CCh-lean gas stream out of the first energy transfer module at a fourth relative humidity less than the third relative humidity; flowing the CCh-lean gas stream into the second energy transfer module at a third temperature; and flowing the exhaust CCh-lean gas stream out of the first energy transfer module at a fourth temperature less than the third temperature.

56. The method of claim 55, comprising: controlling the at least one heater to add heat to the CCh-rich gas stream between the first energy transfer module and the second energy transfer module and form a heated CCh-rich gas stream such that the fourth relative humidity is less than the first relative humidity.

57. The method of claim 50, wherein transferring energy from the at least one energy transfer module to the atmospheric air or transferring energy from the CCh-lean gas stream to the at least one energy transfer module comprises: transferring moisture from the CCh-lean gas stream to the flow of atmospheric air with the first energy transfer module.

58. The method of claim 57, wherein transferring energy from the at least one energy transfer module to the atmospheric air or transferring energy from the CCh-lean gas stream to the at least one energy transfer module comprises: transferring sensible heat from the CCh-lean gas stream to the flow of atmospheric air with the second energy transfer module.

59. The method of claim 57 or 58, wherein transferring energy from the at least one energy transfer module to the atmospheric air or transferring energy from the CCh-lean gas stream to the at least one energy transfer module comprises: transferring moisture from the CCh-lean gas stream to the flow of atmospheric air; andAttorney Docket No.: 30285-0050W01 transferring a heat of absorption from the first energy transfer module to the flow of atmospheric air.

60. The method of any one of claims 57-59, comprising heating a volume of the CO2 capture solution with at least one heater positioned within the volume of the CO2 capture solution.

61. The method of claim 60, comprising collecting the CO2 capture solution from the gas-liquid interface in a basin of the gas-liquid contactor.

62. The method of any one of claims 57-61, comprising: flowing the atmospheric air into the first energy transfer module at a first relative humidity; flowing the CCh-rich gas stream out of the second energy transfer module at a second relative humidity greater than the first relative humidity; flowing the atmospheric air into the first energy transfer module at a first temperature; flowing the CCh-rich gas stream out of the second energy transfer module at a second temperature greater than the first temperature; flowing the CCh-lean gas stream into the second energy transfer module at a third relative humidity; flowing the exhaust CCh-lean gas stream out of the first energy transfer module at a fourth relative humidity less than the third relative humidity; flowing the CCh-lean gas stream into the second energy transfer module at a third temperature; and flowing the exhaust CCh-lean gas stream out of the first energy transfer module at a fourth temperature less than the third temperature.

63. The method of claim 50, wherein the flow path comprises a third energy transfer module and the method comprises transferring energy from the CCh-lean gas stream to the flow of atmospheric air with the third energy transfer module.

64. The method of claim 63, wherein transferring energy from the CCh-lean gas stream to the flow of atmospheric air with the third energy transfer module comprises transferring enthalpy from the CCh-lean gas stream to the flow of atmospheric air with the third energy transfer module.Attorney Docket No.: 30285-0050W0165. The method of either one of claims 63 or 64, wherein transferring energy from the at least one energy transfer module to the atmospheric air or transferring energy from the CO2- lean gas stream to the at least one energy transfer module comprises: transferring moisture from the CCh-lean gas stream to the flow of atmospheric air; and transferring a heat of absorption from the third energy transfer module to the flow of atmospheric air.

66. The method of any one of claims 63-65, comprising heating the CCh-rich gas stream with at least one heater positioned between the second energy transfer module and the third energy transfer module.

67. The method of claim 66, comprising: flowing the atmospheric air into the first energy transfer module at a first relative humidity; flowing the atmospheric air from the first energy transfer module at a second relative humidity greater than the first relative humidity; flowing the atmospheric air into the first energy transfer module at a first temperature; flowing the CCh-rich gas stream out of the first energy transfer module at a second temperature greater than the first temperature; flowing the CCh-lean gas stream into the third energy transfer module at a third relative humidity; flowing the exhaust CCh-lean gas stream out of the first energy transfer module at a fourth relative humidity less than the third relative humidity; flowing the CCh-lean gas stream into the third energy transfer module at a third temperature; and flowing the exhaust CCh-lean gas stream out of the first energy transfer module at a fourth temperature less than the third temperature.

68. The method of claim 67, comprising controlling the at least one heater to add heat to the CCh-rich gas stream between the second energy transfer module and the third energy transfer module such that the fourth relative humidity is less than the first relative humidity.Attorney Docket No.: 30285-0050W0169. The method of any one of claims 44 to 68, comprising moving the at least one energy transfer module between the inlet of the flow path and the outlet of the flow path to transfer the energy between the CCh-lean gas stream and the flow of atmospheric air through the at least one energy transfer module being positioned in the flow path.

70. The method of claim 69, wherein moving the at least one energy transfer module between the inlet of the flow path and the outlet of the flow path comprises rotating the at least one energy transfer module about an axis that has a vertical orientation and extends through a radial center of the at least one energy transfer module.

71. The method of claim 69, wherein moving the at least one energy transfer module between the inlet of the flow path and the outlet of the flow path comprising translating the at least one energy transfer module across the flow path in a first direction from the inlet to the outlet of the flow path to contact the flow of atmospheric air and in a second direction from the outlet to the inlet of the flow path to contact the CCh-lean gas stream.

72. The method of any one of claims 44 to 71, wherein transferring energy from the at least one energy transfer module to the atmospheric air or transferring energy from the CCh-lean gas stream to the at least one energy transfer module comprises flowing the atmospheric air or the CCh-lean gas stream through a plurality of energy transfer channels of the at least one energy transfer module.

73. The method of claim 72, wherein flowing the atmospheric air or the CCh-lean gas stream through the plurality of energy transfer channels comprises contacting an energy transfer material being configured to transfer at least one of thermal energy or chemical energy.

74. The method of any one of claims 44 to 73, wherein flowing the CO2 capture solution along the gas-liquid interface to absorb CO2 from the CCh-rich gas stream into the CO2 capture solution comprises contacting CO2 in the CCh-rich gas stream with an amine solution to form a CCh-rich slurry comprising at least one of carbon containing solids or carbamic acid solids.

75. The method of claim 74, wherein contacting CO2 in the CCh-rich gas stream with the amine solution comprises contacting CO2 in the CCh-rich gas stream with 3-(aminomethyl)- 3,5,5 -trimethy 1 cy cl ohexy 1 ami ne (IPD A) .Attorney Docket No.: 30285-0050W0176. The method of claim 74, wherein contacting CO2 in the CCh-rich gas stream with the amine solution comprises contacting CO2 in the CCh-rich gas stream with a diamine with an aminocyclic compound group.

77. The method of claim 76, wherein contacting CO2 in the CCh-rich gas stream with the diamine comprises contacting CO2 in the CCh-rich gas stream with a cyclohexane-l,3-diamine- 5 R X, wherein:R is a hydrocarbon chain and X is an amino group, andX functionalizes the cyclohexane or the R hydrocarbon chain.

78. The method of claim 76, wherein contacting CO2 in the CCh-rich gas stream with the diamine comprises contacting CO2 in the CCh-rich gas stream with a cyclohexane-l,3-diamine- 5 R, where R is a hydrocarbon chain.

79. The method of claim 77 or 78, wherein R is butane, pentane, hexane, or cycloalkane.

80. The method of any one of claims 44 to 73, wherein flowing the CO2 capture solution along the gas-liquid interface to absorb CO2 from the CCh-rich gas stream into the CO2 capture solution comprises contacting CO2 in the CCh-rich gas stream with a guanidine-based solution to form a CCh-rich slurry comprising carbonate solids.

81. The method of claim 80, wherein the guanidine-based solution comprises a bis- iminoguanidine.

82. The method of claim 81, wherein the bis-iminoguanidine is 2,5-furan-bis- (iminoguanidine) (FuBIG).

83. The method of any one of claims 44 to 73, wherein flowing the CO2 capture solution along the gas-liquid interface to absorb CO2 from the CCh-rich gas stream into the CO2 capture solution comprises contacting CO2 in the CCh-rich gas stream with the CO2 capture solution comprising an alkali metal sorbent to form a CCh-rich capture solution, the method comprising: promoting precipitation of solids in suspension in the CCh-rich capture solution with an amine species being present in the CCh-rich capture solution in addition to the alkali metal sorbent.Attorney Docket No.: 30285-0050W0184. The method of any one of claims 44 to 83, comprising flowing the CCh-lean gas stream in a wash section provided along the flow path and downstream of the at least one gasliquid interface, the wash section being configured to remove aerosolized particles and / or volatilized components of the CO2 capture solution from the CC -lean gas stream.

85. A direct air capture (DAC) system for capturing carbon dioxide (CO2) from atmospheric air, the DAC system comprising: at least one gas-liquid contactor defining at least a portion of a flow path, the at least one gas-liquid contactor comprising: at least one inlet; at least one outlet spaced apart from the at least one inlet; a gas-liquid interface disposed between the at least one inlet and the at least one outlet; a liquid distribution system configured to flow a CO2 capture solution along the gas-liquid interface; at least one fan configured to flow atmospheric air along the flow path from the at least one inlet, along the gas-liquid interface, and to the at least one outlet, to contact the atmospheric air with the CO2 capture solution and absorb CO2 from the atmospheric air into the CO2 capture solution to form a CCh-lean gas stream flowable through the at least one outlet; and at least one energy transfer module, the at least one energy transfer module comprising a plurality of energy transfer channels configured to transfer energy between the CCh-lean gas stream and the flow of atmospheric air along the flow path, the plurality of energy transfer channels defining: a first airflow circuit that comprises a first airflow inlet positioned to receive the flow of atmospheric air and a first airflow outlet fluidly coupled to the first airflow inlet; and a second airflow circuit fluidly separated from the first airflow circuit and comprising a second airflow inlet and a second airflow outlet fluidly coupled to the second airflow inlet and positioned to exhaust the CCh-lean gas stream from the DAC system.

86. The DAC system of claim 85, wherein the at least one energy transfer module comprises at least one enthalpy transfer module, and the plurality of energy transfer channels are configured to transfer enthalpy from the CCh-lean gas stream to the flow of atmospheric air.Attorney Docket No.: 30285-0050W0187. The DAC system of either one of claims 85 or 86, wherein the at least one energy transfer module comprising the plurality of energy transfer channels is configured to transfer energy that comprises: moisture transferred from the CCh-lean gas stream to the flow of atmospheric air; and a heat of absorption from the plurality of energy transfer channels to the flow of atmospheric air.

88. The DAC system of either one of claims 86 or 87, wherein: the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first dry bulb temperature and output a CCh-rich gas stream from the first airflow outlet at a second dry bulb temperature greater than the first dry bulb temperature; and the second airflow circuit is configured to receive the CCh-lean gas stream into the second airflow inlet at a third dry bulb temperature and output an exhaust CCh-lean gas stream from the second airflow outlet at a fourth dry bulb temperature less than the third dry bulb temperature.

89. The DAC system of any one of claims 84-88, wherein: the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first relative humidity and output the flow of atmospheric air from the first airflow outlet at a second relative humidity greater than the first relative humidity; and the second airflow circuit is configured to receive the CCh-lean gas stream through the second airflow inlet at a third relative humidity and output the CCh-lean gas stream from the second airflow outlet at a fourth relative humidity less than the third relative humidity.

90. The DAC system of claim 85, wherein the at least one energy transfer module comprises: a first energy transfer module positioned in the flow path, the first energy transfer module comprising the first airflow circuit, the second airflow circuit, and the plurality of energy transfer channels comprise a first plurality of energy transfer channels; and a second energy transfer module positioned in the flow path, the second energy transfer module comprising a second plurality of energy transfer channels configured to transfer energy between the CCh-lean gas stream and the flow of atmospheric air, the second plurality of energy transfer channels defining:Attorney Docket No.: 30285-0050W01 a third airflow circuit that comprises a third airflow inlet positioned to receive the flow of atmospheric air from the first airflow outlet and a third airflow outlet fluidly coupled to the third airflow inlet; and a fourth airflow circuit that comprises a fourth airflow inlet and a fourth airflow outlet fluidly coupled to the fourth airflow inlet and positioned to exhaust the CCh-lean gas stream to the second airflow inlet.

91. The DAC system of claim 90, wherein the first energy transfer module comprises a thermal energy transfer module, and the second energy transfer module comprises a chemical energy transfer module.

92. The DAC system of either one of claims 90 or 91, wherein the first plurality of energy transfer circuits is configured to transfer sensible heat from the CCh-lean gas stream to the flow of atmospheric air; and the second plurality of energy transfer circuits is configured to transfer moisture from the CCh-lean gas stream to the flow of atmospheric air.

93. The DAC system of claim 92, wherein the at least one energy transfer module is configured to transfer energy that comprises: moisture transferred from the CCh-lean gas stream to the flow of atmospheric air; and a heat of absorption from the second plurality of energy transfer channels to the flow of atmospheric air.

94. The DAC system of any one of claims 90-93, comprising at least one heater positioned between the first airflow outlet and the third airflow inlet, the at least one heater configured to heat the flow of atmospheric air from the first airflow outlet to the third airflow inlet.

95. The DAC system of claim 94, wherein: the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first relative humidity, and the third airflow circuit is configured to output the flow of atmospheric air from the third airflow outlet at a second relative humidity greater than the first relative humidity; the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first temperature and output the flow of atmospheric air from the first airflowAttorney Docket No.: 30285-0050W01 outlet at a second temperature greater than the first temperature; the fourth airflow circuit is configured to receive the CCh-lean gas stream through the fourth airflow inlet at a third relative humidity, and the second airflow circuit is configured to output the CCh-lean gas stream from the second airflow outlet at a fourth relative humidity less than the third relative humidity; and the fourth airflow circuit is configured to receive the CCh-lean gas stream through the fourth airflow inlet at a third temperature, and the second airflow circuit is configured to output the CCh-lean gas stream exits the second airflow outlet at a fourth temperature less than the third temperature.

96. The DAC system of claim 95, comprising a control system communicably coupled to the at least one heater and configured to perform operations comprising: controlling the at least one heater to add heat to the flow of atmospheric air between the first airflow outlet and the third airflow inlet such that the fourth relative humidity is less than the first relative humidity.

97. The DAC system of claim 90, wherein the first energy transfer module comprises a chemical energy transfer module, and the second energy transfer module comprises a thermal energy transfer module.

98. The DAC system of claim 97, wherein the first plurality of energy transfer channels is configured to transfer moisture from the CCh-lean gas stream to the flow of atmospheric air; and the second plurality of energy transfer channels are configured to transfer sensible heat from the CCh-lean gas stream to the flow of atmospheric air.

99. The DAC system of either one of claims 97 or 98, wherein the at least one energy transfer module is configured to transfer energy that comprises: moisture transferred from the CCh-lean gas stream to the flow of atmospheric air; and a heat of absorption from the first plurality of energy transfer channels to the flow of atmospheric air.

100. The DAC system of any one of claims 97-99, comprising at least one heater positioned within a volume of the CO2 capture solution and configured to heat the volume of theAttorney Docket No.: 30285-0050W01CCh capture solution.

101. The DAC system of claim 100, comprising a basin configured to collect the CO2 capture solution from the gas-liquid interface, the at least one heater being positioned within the basin.

102. The DAC system of any one of claims 97 to 101, wherein: the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first relative humidity, and the third airflow circuit is configured to output the flow of atmospheric air from the third airflow outlet at a second relative humidity greater than the first relative humidity; the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first temperature, and the third airflow circuit is configured to output the flow of atmospheric air from the third airflow outlet at a second temperature greater than the first temperature; the fourth airflow circuit is configured to receive the CCh-lean gas stream through the fourth airflow inlet at a third relative humidity, and the second airflow circuit is configured to output the CCh-lean gas stream from the second airflow outlet at a fourth relative humidity less than the third relative humidity; and the fourth airflow circuit is configured to receive the CCh-lean gas stream enters the fourth airflow inlet at a third temperature and output the CCh-lean gas stream from the fourth airflow outlet at a fourth temperature less than the third temperature.

103. The DAC system of claim 97, wherein the at least one energy transfer module comprises: a third energy transfer module positioned in the flow path, the third energy transfer module comprising a third plurality of energy transfer channels configured to transfer energy between the CCh-lean gas stream and the flow of atmospheric air, the third plurality of energy transfer channels defining: a fifth airflow circuit that comprises a fifth airflow inlet positioned to receive the flow of atmospheric air from the third airflow outlet and a fifth airflow outlet fluidly coupled to the fifth airflow inlet; andAttorney Docket No.: 30285-0050W01 a sixth airflow circuit that comprises a sixth airflow inlet and a sixth airflow outlet fluidly coupled to the sixth airflow inlet and positioned to exhaust the CCh-lean gas stream to the fourth airflow inlet.

104. The DAC system of claim 103, wherein the third energy transfer module comprises an enthalpy transfer module.

105. The DAC system of claim 103 or 104, wherein the third plurality of energy transfer channels are configured to transfer enthalpy from the CCh-lean gas stream to the flow of atmospheric air.

106. The DAC system of claim 104 or 105, wherein the at least one energy transfer module is configured to transfer energy that comprises: moisture transferred from the CCh-lean gas stream to the flow of atmospheric air; and a heat of absorption from the third plurality of energy transfer channels to the flow of atmospheric air.

107. The DAC system of any one of claims 103 to 106, comprising at least one heater positioned between the third airflow outlet and the fifth airflow inlet, the at least one heater configured to heat the flow of atmospheric air from the third airflow outlet to the fifth airflow inlet.

108. The DAC system of claim 107, wherein: the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first relative humidity, and the third airflow circuit is configured to output the flow of atmospheric air from the third airflow outlet at a second relative humidity greater than the first relative humidity; the first airflow circuit is configured to receive the flow of atmospheric air through the first airflow inlet at a first temperature, and the third airflow circuit is configured to output the flow of atmospheric air from the third airflow outlet at a second temperature greater than the first temperature; the sixth airflow circuit is configured to receive the CCh-lean gas stream through the sixth airflow inlet at a third relative humidity, and the second airflow circuit is configured to output the CCh-lean gas stream from the second airflow outlet at a fourth relative humidity less than the thirdAttorney Docket No.: 30285-0050W01 relative humidity; and the sixth airflow circuit is configured to receive the CCh-lean gas stream through the sixth airflow inlet at a third temperature, and the second airflow circuit is configured to output the CO2- lean gas stream exits the second airflow outlet at a fourth temperature less than the third temperature.

109. The DAC system of claim 108, comprising a control system communicably coupled to the at least one heater and configured to perform operations comprising: controlling the at least one heater to add heat to the flow of atmospheric air between the third airflow outlet and the fifth airflow inlet such that the fourth relative humidity is less than the first relative humidity.

110. The DAC system of any one of claims 85 to 109, wherein adjacent energy transfer channels of the plurality of energy transfer channels are annular airflow channels circumscribing a radial center.

111. The DAC system of claim 110, wherein the annular airflow channels are defined by a plurality of annular sheets.

112. The DAC system of claim 1 11, wherein the plurality of annular sheets comprises or is made of an energy transfer material being configured to transfer at least one of thermal energy or chemical energy.

113. The DAC system of claim 112, wherein the energy transfer material is provided coated onto at least one annular sheet of the plurality of annular sheets.

114. The DAC system of any one of claims 85 to 113, wherein the at least one energy transfer module comprises a thermal wheel that defines a wheel axis having a vertical orientation, the thermal wheel configured to rotate about the wheel axis.

115. The DAC system of any one of claims 85 to 113, wherein: the at least one energy transfer module comprises a thermal wheel that defines a wheel axis having a vertical orientation, the thermal wheel configured to rotate about the wheel axis, and the thermal wheel comprises a plurality of annular sheets being concentric about the wheelAttorney Docket No.: 30285-0050W01 axis, each annular sheet of the plurality of annular sheets spaced apart from another annular sheet of the plurality of annular sheets in a direction radial to the wheel axis, each energy transfer circuit of the plurality of energy transfer circuits comprising a circumferential air passage defined between adjacent annular sheets of the plurality of annular sheets.

116. The DAC system of claim 115, wherein at least one annular sheet of the plurality of annular sheets comprises corrugated metal.

117. The DAC system of claim 115 or 116, wherein the plurality of annular sheets comprises a desiccant coating.

118. The DAC system of any one of claims 85 to 109, wherein adjacent energy transfer channels of the plurality of energy transfer channels are defined by a plurality of adjacent energy transfer units operatively connected to one another to form a belt-like structure being translatable across the flow path.

119. The DAC system of claim 118, wherein the at least one energy transfer module comprises an external drive to actuate translation of the plurality of adjacent energy transfer units across the flow path.

120. The DAC system of claim 118 or 119, wherein the plurality of energy transfer units are organized as a loop, and each energy transfer unit of the plurality of energy transfer units is translated across the flow path a first time in a first direction and a second time in a second direction, the second direction being the opposite of the first direction.

121. The DAC system of any one of claims 118 to 120, wherein the plurality of energy transfer units comprise: a plurality of inlet energy transfer units comprising the energy transfer channels defining the first airflow circuit receiving the flow of atmospheric air; and a plurality of outlet energy transfer units comprising the energy transfer channels defining the second airflow circuit receiving the CCh-lean gas stream.Attorney Docket No.: 30285-0050W01122. The DAC system of claim 121, wherein the first airflow circuit extends over an entire surface of the at least one inlet, and the second airflow circuit extends over an entire surface of the at least one outlet.

123. The DAC system of any one of claims 118 to 122, wherein each energy transfer unit comprises a pair of spaced-apart partitions protruding outwardly from a conveying surface, and two adjacent partitions at least partly define a gap or enclosure therebetween that is sized and shaped to receive a desiccant.

124. The DAC system of any one of claims 85 to 123, wherein the at least one energy transfer module is positioned in the flow path to have the first airflow circuit upstream of the gasliquid interface and the second airflow circuit downstream of the gas-liquid interface.

125. The DAC system of any one of claims 85 to 124, wherein the at least one inlet comprises at least one vertical inlet, and the at least one outlet comprises at least one vertical outlet spaced apart from the at least one vertical inlet and separated by the gas-liquid interface, and the at least one energy transfer module is positioned to intersect the flow path in the at least one vertical inlet and the at least one vertical outlet.

126. The DAC system of any one of claims 85 to 125, wherein the at least one energy transfer module is provided as part of the gas-liquid contactor, with an inlet of the flow path corresponding to the at least one inlet of the gas-liquid contactor, and an outlet of the flow path corresponding to the at least one outlet of the gas-liquid contactor.

127. The DAC system of any one of claims 85 to 125, wherein first airflow circuit is positioned upstream of the at least one inlet of the gas-liquid contactor and the second airflow circuit is positioned downstream of the at least one outlet of the gas-liquid contactor.

128. The DAC system of claim 127, wherein the at least one energy transfer module is provided separately from the gas-liquid contactor, the at least one energy transfer module being fluidly connected to the gas-liquid contactor via an interconnecting duct network further defining the flow path.Attorney Docket No.: 30285-0050W01129. The DAC system of claim 128, wherein the gas-liquid contactor comprises: a second gas-liquid interface being positioned downstream of the gas-liquid interface along the flow path; and a wash water distribution system to provide wash water along the second gas-liquid interface, the second gas-liquid interface serving as a wash section of the gas-liquid contactor and being configured to remove volatilized components and / or aerosolized particles of the CO2 capture solution from the CCh-lean gas stream.

130. The DAC system of any one of the previous claims 85 to 129, wherein the gasliquid interface is configured to contact the atmospheric air with the CO2 capture solution in a cross-flow arrangement, a co-current flow arrangement, or a counter-current flow arrangement.

131. The DAC system of any one of the previous claims 85 to 130, wherein the gasliquid interface comprises at least one packing.

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