Process of sub-atmospheric and low temperature. steam desorption for use with direct air carbon capture (DAC)

Abstract

A system for capturing carbon dioxide from the atmosphere includes an absorption cycle, a desorption cycle, and a collection cycle, a plurality of lines arranged with a plurality of valves and a plurality of pumps to create a plurality of circulation circuits, a pressure vessel configured to receive a first flow, a second flow and discharge a combined third flow, a sorbent filter arranged to filter the first flow within the pressure vessel during the absorption cycle, a heat source configured to heat the second flow prior to entering the pressure vessel, a heat exchanger configured to cool the combined third flow after it is discharged by the pressure vessel, a containment vessel configured to receive and store a flow of carbon dioxide gas during the collection cycle, where the desorption cycle is performed at sub-atmospheric pressure.

Description

Docket No. 2023PF12288 PROCESS OF SUB-ATMOSPHERIC AND LOW TEMPERATURE STEAM DESORPTION FOR USE WITH DIRECT AIR CARBON CAPTURE (DAC) CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of US provisional application number 63 / 528,558 filed on July 24, 2023. BACKGROUND

[0002] Removing CO2from the atmosphere, commonly referred to as carbon capture or direct air carbon capture (DAC) has been implemented on small and industrial scales. The economics of carbon capture are driven by the energy costs of the processes used and the filter or sorbent material used in the carbon capture process. Two of the main methods of DAC are liquid and solid sorbent DAC. Solid sorbents, such as a solid base material coated with a liquid amine solution(s). The base material and liquid amine coating can optionally be bonded together. Amine formulations can be produced to coat beads or spheres of plastic, polymer, or other suitable material. Some of the issues involved in the use of amine coated or impregnated sorbent material is the service life of the filter material or sorbent due to degradation of the amine material. The present invention provides a cost-effective and energy-effective way of continuously operating a direct air capture (DAC) apparatus using a solid sorbent.

[0003] Different methods of capturing CO2from the atmosphere or air streams are available, but the method of direct air capture by use of a solid sorbent in a direct air capture unit or other suitable sorbent configuration is discussed in detail below.

[0004] Typical DAC methods involve flowing atmosphere across a sorbent filter media typically referred to simply as a "filter" in an absorption cycle. The filter is contained within a sealable container typically referred to as an air contactor or simply a contactor, as the filter contacts the air flow of atmosphere within the “contactor.” Once sorbent filter media has reached a designated level of absorption, typically between 50 and maximum absorption for the sorbent media, a desorption cycle is initiated. The desorption of a solid sorbent currently requires a temperature swing or vacuum swing to release the captured CO2from the sorbent media. Temperature swing desorption uses a heat source and a heated working fluid. Any number of known industrial methods of heating can be used, including but not limited to resistive heating of the working fluid. Heating of the working fluid generally represents the majority of the energyDocket No. 2023PF12288 required by the desorption cycle. Prior to introducing the heated working fluid within the contactor during the desorption cycle, a vacuum is required within the contactor to remove the atmosphere or air within the contactor to lower the level of Oxygen. Current amine and other solid sorbent materials deteriorate when exposed to Oxygen and the rate of degeneration is increased with the temperature of the sorbent. Typically, sorbent medias designed for DAC units utilizing atmospheric air flows, ~21% O2at ambient temperature ranges, and are designed to last a service interval that is based on atmospheric / ambient conditions. The service life of the sorbent filter is determined by the amount of degradation that occurs in every absorption and desorption cycle. Service life can be increased by limiting the temperature and the amount of O2 that the sorbent media is exposed to during each absorption and desorption cycles. Current methods of desorption can use steam as the working fluid. When steam is used as the working fluid, the contactor is a sealable pressure vessel that needs to resist collapsing under a vacuum and the pressures generated by the steam, which may be superheated. The structural requirements of a contactor used with steam as the working fluid are significant and generally required the use of corrosion resistant materials with sufficient material properties for the particular application, such as stainless steel. Even with the use of metals such as stainless steel or similar metals contactors have significant structural requirements that translates into a significant volume / mass of material which needs to be heated up with the filters to bring the filters to the desired desorption temperature, the inverse is also true, the contactor will need to be cooled back to the desired absorption temperature for a particular application. The thermal mass of the contactor and sorbent media is directly related to the amount of energy required for the desorption cycle of a DAC-unit.

[0005] One process for capturing CO2from ambient air uses a solid sorbent that is manufactured as a solid bead or sphere that is coated with a sorbent material, such as an amine. The solid sorbent can absorb CO2molecules via reactions with amine groups coating the bead or other suitable configuration known in the art. During adsorption, air or atmosphere needs to be circulated around the sorbent to facilitate the removal or absorption of CO2 from the air that is circulated across or around the solid sorbent. During desorption or the process of removing the absorbed CO2 from the sorbent, the sorbent needs to be pneumatically sealed in a container so that the CO2released from the sorbent can be isolated and collected. To desorb the CO2from the sorbent, the contactor acts as a pressure vessel, the contactor is pneumatically sealed and the pressure within the contactor is reduced to create a partial vacuum. As discussed above, theDocket No. 2023PF12288 sorbent material will decompose in the presence of Oxygen and the rate of decomposition is increased by the temperature of the sorbent, this issue is typically addressed by reducing the amount of Oxygen in contact with the sorbent during the desorption cycle. The latter can be done by purging the contactor with another medium and / or lowering the absolute pressure in the contactor. Typically, steam is used for both purging and heating of the sorbent. After O2and or CO2levels have been reduced within the contactor, the contactor is then purged or filled with steam, which raises the temperature of the sorbent and the structure of the contactor. At the start of the desorption cycle, the air pressure in the contactor is lowered by use of a vacuum pump, thereby lowering the amount of air and or Oxygen that is mixed with the CO2 produced or separated from the sorbent during the desorption process of the DAC-unit.

[0006] The current challenges of configurations of sorbent filters designed for use with a solid amine loaded sorbent are the significant amount of heat and electricity demand required to operate both the adsorption and desorption phases. As discussed above steam can be used to heat the contactor, a DAC-unit that minimizes the amount of heat and or electricity required for operation is desirable. In order to minimize heat and or electrical requirements of a DAC-unit, a low thermal mass and enclosed volume reduces the amount of energy needed for heating the contactor and sorbent media, reduces the amount of work required by a vacuum pump during desorption, and lowers the pressure drop through the sorbent filter which reduces the flow rate requirements of the fans used during the adsorption cycle to circulate air around the sorbent.

[0007] Current DAC-units pressurize the contactor and other components of the system to pressures well above atmospheric pressure. Thermodynamic constraints of converting water into steam at pressures above atmospheric, such as boiling water in a stove or super heating steam requires significant amounts of energy or heat to overcome the latent heat of vaporization of water. As discussed above, heating of the sorbent during the desorption cycle represents the majority of energy required to capture atmospheric carbon with a solid sorbent using a temperature swing. Current DAC-units do not attempt to perform the temperature swing required by the desorption cycle at sub-atmospheric pressures or under vacuum due to the increased technical difficulties required by a system that conducts the desorption cycle under vacuum or at sub-atmospheric pressures.

[0008] One of the technical difficulties created by performing the temperature swing under vacuum is the temperatures and pressures required to condense sub-atmospheric steam. Condensing steam at sub-atmospheric pressures, particularly in volumes or mass flow ratesDocket No. 2023PF12288 greater than what can be accomplish at laboratory scale is generally limited by the operation of the condenser used to cool the steam back into water. More particularly, the heat exchange fluid used to remove heat from the sub-atmospheric steam needs to be at a temperature significantly below the phase change temperature of steam at the operating pressure of the DAC-unit. In a sub-atmospheric DAC, as steam condenses to water, the pressure drops (increases the amount of vacuum in a sub-atmospheric DAC-unit due to the decrease in volume of steam), and so does the temperature required for the phase change of steam into water. As pressure within the DAC-unit approaches 0.05bar(a), the phase change temperature of water approaches 30°C. For a DAC-unit to operate the desorption cycle under vacuum, for example at 0.05bar(a), the temperature required to convert steam into water is ~30C. In order to effectively condense all of the steam in the DAC-unit, the heat exchange fluid must be at a significantly lower temperature than the steam. For sub-atmospheric DAC units, this temperature is typically at our below ambient conditions, requiring uneconomical and / or inefficient heat rejection cycles that utilize refrigerant based heat exchangers or chillers to maintain operating temperatures. Conventional heat exchangers or condensers are designed to operate at or above atmospheric pressure with water or other refrigerant acting as the heat exchange fluid. Condensation can be supplemented by the use of mechanical steam compressors but similar to conventional heat exchangers, these are designed to operate at pressures above atmospheric.

[0009] The desorption cycle is typically conducted after a vacuum cycle or purge of the contactor to reduce or eliminate the amount of Oxygen exposed to the sorbent material to reduce degradation or decomposition. Conventional vacuum pumps are not designed with vapor tolerances compatible with temperatures at or below 30C. Specifically, conventional vacuum pumps are not compatible with sub-atmospheric steam due to the inherent amount of water vaper and the temperatures at which sub-atmospheric steam exits. BRIEF SUMMARY

[0010] It is therefore a goal of the present invention to provide a carbon capture system that overcomes the above-mentioned disadvantage(s). In particular, a carbon capture system that reduces the energy required to heat the sorbent and reducing the maximum temperature the sorbent reaches during the carbon capture process by using sub-atmospheric steam during the desorption cycle of the carbon capture system to advantageously reduce energy costs and prolonging the service life of the sorbent.Docket No. 2023PF12288

[0011] The object of the invention is achieved by, a system for capturing carbon dioxide from the atmosphere includes an absorption cycle, a desorption cycle, and a collection cycle, a plurality of lines arranged with a plurality of valves and a plurality of pumps to create a plurality of circulation circuits, a pressure vessel configured to receive a first flow, a second flow and discharge a combined third flow, a sorbent filter arranged to filter the first flow within the pressure vessel during the absorption cycle, a heat source configured to heat the second flow prior to entering the pressure vessel, a heat exchanger configured to cool the combined third flow after it is discharged by the pressure vessel, a containment vessel configured to receive and store a flow of carbon dioxide gas during the collection cycle, where the desorption cycle is performed at sub-atmospheric pressure.

[0012] Prior art DAC-systems that have used thermal cycling as a method to release CO2 from a solid sorbent have utilized pressures above atmospheric, i.e. pressurized steam above atmospheric pressures. Steam is produced by boiling or phase changing water at a phase change temperature or boiling point, the properties of steam increase the temperature of the boiling point with pressure. The amount of energy required to raise the temperature of water and eventually produce steam will be higher for a positively pressurized system versus an atmospheric or sub-atmospheric system. The present invention advantageously utilizes sub- atmospheric pressures to reduce the amount of energy needed to produce steam and thereby reduces the amount of energy needed for the desorption cycle of a DAC-unit. Use of solid sorbent in DAC-units is limited by the decomposition of the sorbent media, which deteriorates or decomposes when exposed to Oxygen. The deterioration is intensified or accelerated by higher temperatures. Another advantage of sub-atmospheric steam utilization in a DAC-system is a reduced maximum temperature of the sorbent media, allowing for longer service life of existing sorbent medias.

[0013] In one embodiment where the first flow is atmospheric air.

[0014] In one embodiment where the second flow is sub-atmospheric steam.

[0015] In one embodiment where a pressure within the pressure vessel, or contactor, during the desorption phase is at or below 0.5 bar absolute.

[0016] In one embodiment where a steam injector is used to maintain the sub-atmospheric pressures within the containment vessel.

[0017] In one embodiment the maximum temperature of the system for capturing carbon dioxide is at or below 90 degrees Celsius. This advantageously limits or reduces the amount ofDocket No. 2023PF12288 deterioration of the sorbent media as well as reduces the amount of energy required to boil the sub-atmospheric steam.

[0018] In one embodiment, a method for capturing carbon dioxide from a CO2 containing gas includes the steps of configuring a pressure vessel to receive a first flow, a second flow and discharge a combined third flow, installing a sorbent filter in the pressure vessel and configuring the sorbent filter to filter the first flow during an absorption cycle, continuing the absorption cycle until the sorbent filter has absorbed a predetermined level of CO2, sealing the pressure vessel prior to the initiation of a desorption cycle with a plurality of lids configured to bring the pressure vessel in fluid communication with a plurality of line, valves and pumps, configuring a heat source to heat the second flow prior to entering the pressure vessel, flowing the second flow into the pressure vessel during the desorption cycle, discharging the third flow from the pressure vessel at the end of the desorption cycle, configuring a heat exchanger to cool the combined third flow after it is discharged by the pressure vessel, separating CO2 from the combined third flow, configuring a containment vessel to receive and store a flow of carbon dioxide gas during a collection cycle, where the desorption cycle is performed at sub- atmospheric pressure.

[0019] In one embodiment, a method for capturing carbon dioxide where the first flow is atmospheric air.

[0020] In one embodiment, a method for capturing carbon dioxide where the second flow is sub-atmospheric steam.

[0021] In one embodiment the containment vessel is a piping circuit designed to direct the captured carbon dioxide gas to a subsequent process.

[0022] In one embodiment of the present invention is a method of capturing atmospheric carbon dioxide that uses steam generated at sub-atmospheric pressures or under vacuum to reduce the amount of energy required by the latent heat of vaporization of water and the entire DAC-unit.

[0023] In one embodiment of the present invention is a method of capturing atmospheric carbon dioxide that uses steam generated at pressures above vacuum and brought to sub- atmospheric pressure via the use of a vacuum pump and control valve prior to introduction into the contactor or use in the desorption cycle.

[0024] Other technical features may be readily apparent to one skilled in the art from the following figures, descriptions, and claims.Docket No. 2023PF12288 BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0025] To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced.

[0026] FIG. 1 illustrates a DAC-system in accordance with an embodiment of the present invention.

[0027] FIG. 2 illustrates a DAC-system in accordance with one embodiment.

[0028] FIG. 3 illustrates a condensation system in accordance with one embodiment.

[0029] FIG. 4 illustrates a DAC-system in accordance with one embodiment.

[0030] FIG. 5 illustrates a sorbent filter within the contactors of the embodiment of FIG. 4.

[0031] FIG. 6 is a view in cross section of the embodiment of FIG. 4. DETAILED DESCRIPTION

[0032] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in this description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

[0033] Various technologies that pertain to apparatus and methods will now be described with reference to the drawings, where like reference numerals represent like elements throughout. The drawings discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged apparatus.

[0034] It is to be understood that functionality that is described as being carried out by certain system elements may be performed by multiple elements. Similarly, for instance, an element may be configured to perform functionality that is described as being carried out by multipleDocket No. 2023PF12288 elements. The numerous innovative teachings of the present application will be described with reference to exemplary non-limiting embodiments.

[0035] Also, it should be understood that the words or phrases used herein should be construed broadly, unless expressly limited in some examples. For example, the terms “including,” “having,” and “comprising,” as well as derivatives thereof, mean inclusion without limitation. The singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Further, the term “and / or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. The term “or” is inclusive, meaning and / or, unless the context clearly indicates otherwise. The phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like. Furthermore, while multiple embodiments or constructions may be described herein, any features, methods, steps, components, etc. described with regard to one embodiment are equally applicable to other embodiments absent a specific statement to the contrary.

[0036] Also, although the terms "first", "second", "third" and so forth may be used herein to refer to various elements, information, functions, or acts, these elements, information, functions, or acts should not be limited by these terms. Rather these numeral adjectives are used to distinguish different elements, information, functions or acts from each other. For example, a first element, information, function, or act could be termed a second element, information, function, or act, and, similarly, a second element, information, function, or act could be termed a first element, information, function, or act, without departing from the scope of the present disclosure.

[0037] Also, unless specified or limited otherwise, the terms “mounted”, “connected”, “supported”, and “coupled” and variations thereof are used broadly and encompass direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.

[0038] In addition, the term "adjacent to" may mean: that an element is relatively near to but not in contact with a further element; or that the element is in contact with the further portion, unless the context clearly indicates otherwise. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. Terms “about” orDocket No. 2023PF12288 “substantially” or like terms are intended to cover variations in a value that are within normal industry manufacturing tolerances for that dimension. If no industry standard as available a variation of 20 percent would fall within the meaning of these terms unless otherwise stated.

[0039] FIG. 1 is an elevated view of an embodiment of a carbon capture system 200 that includes a frame 110 assembled on a base 104 and configured to be sealed such that the carbon capture system 200 has an inlet 102 and an outlet 108 for an air flow 206. The inlet 102 and outlet 108 are positioned for this particular embodiment but a person skilled in the art will know that the direction of flow or other design choices would require reversal or repositioning of the inlet 102 and or outlet 108.

[0040] Figure 2 is a schematic view of an embodiment of a DAC-system or carbon capture system 200 in accordance with an embodiment of the invention. The carbon capture system 200 is designed to capture CO2 from a flow of atmospheric air or air flow 206 that is directed from the inlet 102 through an air contactor or contactor 202. The contactor 202 is a pressure vessel that is configured to receive a first flow or air flow 206 and a second flow or steam flow 208. The carbon capture system 200 requires several cycles to extract pure or high concentration CO2gas from the air flow 206, cycles including an absorption, desorption, cooling and a collection cycle and other necessary cycles to complete the process of the DAC-system. The carbon capture system 200 includes a variety of lines or piping, valves 218 and pumps 214 typically required of a filtration / circulation system involving two or more fluid flows. Depending on the application the valves 218 can be one way, two-way, three-way or whatever configuration is required by a particular application, as practiced in the art. The carbon capture system 200 includes a pressure vessel or contactor 202 which is configured to hold a sorbent filter assembly 706 that is designed to absorb CO2when exposed to the air flow 206. Generally, a fan, which can be configured as part of the inlet 102, is used to push the air flow 206 through the contactor 202 and sorbent filter during the absorption cycle of the carbon capture system 200. In an embodiment, a blower or other known method or device can be configured as part of the outlet 108 and used to pull the air flow 206 through the contactor 202 and sorbent filter during the absorption cycle of the carbon capture system 200. In an embodiment, the contactor 202 can be substantially cylindrical or barrel shaped with open ends that allow fluid flow through the contactor 202. During the absorption cycle the valves 218 that control the second flow or steam flow 208 are in the closed position and the air flow 206 enters one end of the contactor 202 and exits the other end. Prior to and during the absorption cycle the contactorDocket No. 2023PF12288 202 is at or near ambient temperature, rather the same or near the temperature of the incoming air flow 206. Once the air flow 206 has been passed through the contactor 202 it is discharged from the carbon capture system 200 via an exhaust or outlet 108. The positioning of the inlet 102, outlet 108, and valves 218 in figures 1 and 2 is for clarity and a person skilled in the art would know that other configurations are possible.

[0041] At a predetermined point, which can be determined by absorption time, the capacity of the sorbent filter, or any other limitation of the carbon capture system 200, the carbon capture system 200 enters a desorption cycle. The carbon capture system 200 can include a single or several contactors 202 arranged in a sequence or array to allow for continuous operation of the carbon capture system 200. As seen in Figure 4, the carbon capture system 200 can be arranged around a central axis with the arrangement of contactors 202 evenly distributed around a central axis 402. During the desorption cycle, one or a group of contactors 202 are pneumatically sealed and a vacuum can be initiated within the contactor 202 to extract the remaining air within the contactor 202 from the absorption cycle. Alternatively, or in addition, the contactor 202 can be purged with the steam flow 208 prior to the desorption cycle and the heating of the contactor 202.

[0042] In the embodiment seen in FIG. 2, the steam flow 208 is introduced into the contactor 202 at sub-atmospheric pressures at 0.5 bar(a) and at temperatures at 81 degrees Celsius. The pressure of steam flow 208 can be at or below a pressure 0.7 bar(a) and below a temperature of 90 degrees Celsius. The steam flow 208 is produced by heating water from a feed water tank 220 with a steam generator 204 and circulated into the contactor 202 via pump 214 or any known circulation method. The steam flow 208 is introduced at a temperature above the corresponding ambient temperature sufficient to produce the temperature swing necessary to release the CO2from the sorbent material of the sorbent filter. Unlike DAC-systems that use pressurized steam (pressures above atmospheric or Zero-gauge pressure) the temperature of the steam flow 208 can be kept below 90 degrees Celsius. This is advantageous because sorbent materials are known to be sensitive to temperature and decomposition or degradation will occur at faster rates at higher temperatures. By operating at sub-atmospheric pressures the carbon capture system 200 is able to prolong the service life of sorbent materials by keeping the maximum temperature of the contactor 202 below 90 degrees Celsius. Additionally, the energy or heat required to raise the temperature of the thermal mass of the contactor 202 and sorbent filter contained within is advantageously reduced by producing sub atmospheric steam.Docket No. 2023PF12288 Regardless of the type of steam generator 204 used to heat the steam in the steam flow 208, the amount of energy required is less than what would be required in a pressurized steam system (atmospheric or greater pressure).

[0043] During the desorption cycle the steam flow 208 passes through the contactor 202. Once the steam flow 208 has been discharged from the contactor 202 a collection cycle begins by cooling the steam flow 208. The combined flow 308, including discharged steam flow 208, enters a heat exchanger 300. The heat exchanger 300 can be a single pass or multi pass heat exchanger as well as a series of sequential heat exchangers. The heat exchanger 300 cools thesteam flow 208 until the steam condenses into water which separates the CO2 gas released bythe sorbent material. The CO2 gas is discharged into a containment vessel 212 for storage of the CO2 by the operation of pump 214 and valve 218, which can be located upstream or downstream of the containment vessel 212 or both. The containment vessel 212 in FIG. 2 is shown for clarity and a person skilled in the art would know that the CO2 gas can be directed to another process, such as a compressor. A flow of condensate water can be returned to the steam generator 204 or a sequential heat exchanger 300, via drain 216.

[0044] Referring to FIG. 2 and FIG. 6, the desorption cycle is completed once the steam flow 208 has circulated through the contactor 202 and sorbent filter for a predetermined amount of time or the sorbent filter has reached a predetermined temperature. The valves 218 that control the steam flow 208 are closed and the contactor 202 is allowed to cool or return to ambient temperature. Any residual water that remains or forms within the contactor during the cooling cycle exits the contactor 202 via drain 216 to limit or prevent contact between the water and the sorbent filter media. Once the contactor 202 has reached a predetermined temperature, the end caps 602 are removed from the desorbed contactor 202 and the absorption cycle for the contactor 202 can begin again. The end caps 602 are moved to another contactor 202 within the carbon capture system 200 according to a predetermined sequence or service schedule, to begin another desorption cycle of the continuous operation of the carbon capture system 200.

[0045] In an embodiment, the steam flow 208 enters the contactor 202 at its saturation temperature. Any heat lost to the piping or sorbent, through the piping to the environment, or used to strip CO2 from the sorbent media (called the 'enthalpy of desorption') results in condensation of some of the steam flow 208. The saturation temperature of the water vapor is determined by its partial pressure in the combined flow 308 of the steam flow 208 and the CO2gas released by the sorbent media. Depending on the sorbent media, water vapor may also beDocket No. 2023PF12288 released with the CO2 gas. As the temperature decreases and steam flow 208 is condensed at constant pressure, the amount of water vapor in the combined flow 308 decreases while the amount of CO2 (which does not condense) remains the same. This means the partial pressure of the water vapor is decreasing, and therefore the temperature must drop even lower to condense more steam within the combined flow 308. In an embodiment, desorption begins with filling the contactor 202 with the steam flow 208 and CO2 removed from the sorbent media at 81°C and 0.5 bar. The combined flow 308 is outputted from the heat exchanger or steam condensation system 300 at atmospheric pressure and at or below 49C.

[0046] A steam condensation system or condensation system 300 can be seen in Figure 3. When used in place of a conventional heat exchanger, with a carbon capture system 200, the condensation system 300 will receive the combined flow 308 of the steam flow 208 and the released CO2 gas after the steam flow 208 has been circulated into or through the contactor 202 during a desorption cycle. In this embodiment a steam injector, which in this application is commonly referred to as a steam ejector 310, is used to reduce the pressure within the contactor 202 to 0.05 Bar or below, but other known methods such as a conventional vacuum pump may be used. The contactor 202 is filled with sub-atmospheric steam flow 208, at a pressure of 0.05 Bar or below, from the steam generator 204. The sub-atmospheric pressure of 0.05 bar is maintained by the steam injector 310 which is not limited by the vapor content present in the contactor 202, unlike conventional vacuum pumps. At the end of the desorption cycle the valves 218 place the combined flow 308 in fluid communication with the cooling circuits 302, shown as three cooling circuits in this embodiment. To begin condensation, the water jet injector or water ejector 304 in the first or only cooling circuit 302 injects pressurized water into condensation tank 314. Water is used as the motive fluid in the cooling circuits 302, and a flow of motive water 312 is injected via the water injectors 304 into the condensation tanks 314 at a pressure and temperature designed to advantageously use the principles of water jet injectors to draw the combined flow 308 into the condensation tanks 314. Ideally, the motive water 312 needs to be at a lower temperature than the steam flow 208 or combined flow 308 which can be in a temperature range of 70-90 degrees Celsius. The motive water 312 is injected into the condensation tank 314 at a higher pressure than the steam flow 208 or combined flow 308. In one example water at ambient pressure (1 Bar) can be injected into the condensation tanks 314 at ~80 degrees Celsius. This represents a cost savings versus the use of pressurized steam in the desorption cycle, like prior art DAC-systems, because little to no energy isDocket No. 2023PF12288 required by the conventional heat exchanger 210 to cool the motive water 312 to ~80 degrees Celsius or below because of the close proximity to ambient temperature. Additionally, significant cost savings exist versus the use of a conventional condensing methods, such as using a heat exchanger operating at temperatures below 80 degrees Celsius through the use of a refrigerant and or a steam compressor (both of which require constant energy input). Additionally, conventional heat exchangers and steam compressors are not designed to work at sub atmospheric pressures or with the presence of vapor levels that sub-atmospheric steam would produce.

[0047] In the present invention, the pressure within the condensation tank 314 is raised by the injection of the motive water 312, regardless of the original temperature of the combined flow 308, injection of pressurized motive water 312 will raise the temperature at which the steam within the condensation tank 314 condenses into water. A person skilled in the art would know that, in addition to water, other fluids or mixtures of water can be used as the motive fluid 312. Depending on the design requirements of the condensation system 300, a single pass or multi pass cooling circuit(s) 302 can be implemented. The CO2gas or remaining combined flow 308 can be collected from the discharge 316 of the condensation tank 314 or circulated through another or a series of cooling circuits 302 until ultimately being stored in a containment vessel 212, sent to another process (such as a compressor) or being returned to the carbon capture system 200. The motive water 312 can be sent to an overflow tank 320 at the end of each cooling circuit 302, through the use of a float trap 306 or similar method capable of maintaining a constant or maximum water level within the condensation tanks 314.

[0048] FIG. 4 is an embodiment of a carbon capture system 200 that includes a lower support ring 414 attached to a base 104. In this embodiment the lower support ring 414 supports a plurality of segmented sections, each of which contains a contactor 202. The lower support ring 414 is configured to create a ring of segmented sections and contactors 202, which in this embodiment is made up of six segments containing a single contactor 202 but other embodiments can include additional segments or increased number of contactors 202 per segment. Additionally, the shape of the carbon capture system 200 is not limited to a ring or circular design, any shape that can be configured around a central axis 402 can be used. The frame 110 includes an upper support ring 416 and a lower support ring 414 attached to the vertical supports 412. A series of track segments 406 are attached to the upper support ring 416 and lower support ring 414 completing an upper track 418 and a lower track 420 respectively.Docket No. 2023PF12288 An upper swingarm 408 is configured to revolve around the upper track 418, similarly a lower swingarm 410 is configured to revolve around the lower track 420. The upper swingarm 408 is supported by the track segments 406 that complete the upper track 418 and is configured to translate around central axis 402 on the path defined by the upper track 418. Similarly, the lower swingarm 410 is supported by the track segments 406 that complete the lower track 420 and is configured to translate around the central axis 402 on the path defined by the lower track 420. The upper swingarm 408 and lower swingarm 410 can be configured to move in unison or independently to any particular segmented section and the contactor(s) 202 contained within the segment. The upper swingarm 408 and lower swingarm 410 can be supported by a central hub 422 located at the center of the frame 110 of the carbon capture system 200.

[0049] A sorbent filter 706 in accordance with an embodiment of the present invention can be seen in FIG. 5. The exact configuration of the sorbent filter 706 is dependent on the sorbent media used in the sorbent filter 706 as well as the structural support required by the sorbent media to accommodate the pressures and temperatures of the carbon capture system 200.

[0050] In one embodiment seen in FIG. 6, continuous operation is facilitated by arrangement of a series of contactors 202 arranged around a central hub 422 and an upper swingarm 408 and lower swingarm 410 facilitates the desorption of one or multiple contactors 202 in a defined sequence, for example a continuous loop around the central hub 422. When a contactor 202 enters the desorption cycle, both of the ends of the contactor 202 are pneumatically sealed with end caps 602. The contactor 202 is substantially cylindrical in shape and has an upper flange and lower flange, each configured to mate with a main flange of an end cap 602. A seal is installed between the contactor 202 and end cap 602, in this embodiment the seal is an o-ring that is installed in an o-ring groove between the upper or lower flange of the contactor 202 and an end cap 602. A person skilled in the art will know that other methods of sealing between the contactor 202 and end cap 602 are possible, such as gaskets, tapered interfaces and v-band configurations. The upper swingarm 408 and lower swingarm 410 each have a series of actuators 612 that moves the end cap 602 towards or away from the contactor 202. In an embodiment, the actuator 612 is limited to movement in the vertical direction, along the axial length of the central axis 402. The end cap 602 is attached to the piping at the orifice 606 via flange 610 via conventional methods, such as mechanical bolting. The actuators 612 move the end cap 602 and piping toward the contactor 202 in unison or independently with only requiring sealing between the contactor 202 and end caps 602 to complete the fluid circuit. TheDocket No. 2023PF12288 actuator 612 is able to move or press the end cap 602 against the contactor 202 with sufficient contact pressure to create a pneumatic seal. The interface between the contactor 202 and end cap 602 can have alignment features that center the end cap 602 on the contactor 202. The piping rotates with the swing arms and may have additional connections that are necessary to facilitate translation to another contactor within the carbon capture system 200.

[0051] Although various embodiments that incorporate disclosed concepts have been shown and described in detail herein, those skilled in the art can readily devise many other varied embodiments that still incorporate these disclosed concepts. Disclosed embodiments are not limited to the specific details of construction and the arrangement of components set forth in the description or illustrated in the drawings. Disclosed concepts may be implemented by other implementations, and of being practiced or of being carried out in various ways, which now would become apparent to one skilled in the art.

[0052] None of the description in the present application should be read as implying that any particular element, step, act, or function is an essential element, which must be included in the claim scope: the scope of patented subject matter is defined only by the allowed claims. Moreover, none of these claims are intended to invoke a means plus function claim construction unless the exact words "means for" are followed by a participle.

Claims

Docket No. 2023PF12288 CLAIMS What is claimed is:

1. A system (200) for capturing carbon dioxide from the atmosphere comprising: an absorption cycle, a desorption cycle, and a collection cycle, a plurality of lines (222) arranged with a plurality of valves (218) and a plurality of pumps (214) to create a plurality of circulation circuits, a pressure vessel (202) configured to receive a first flow (206), a second flow (208) and discharge a combined third flow (308), a sorbent filter (706) arranged to filter the first flow (206) within the pressure vessel (202) during the absorption cycle, a heat source (204) configured to heat the second flow (208) prior to entering the pressure vessel (202), a heat exchanger (300) configured to cool the combined third flow (308) after it is discharged by the pressure vessel (202), a containment vessel (212) configured to receive and store a flow of carbon dioxide gas during the collection cycle, wherein the desorption cycle is performed at sub-atmospheric pressure.

2. The system (200) of claim 1, wherein the first flow (206) is atmospheric air.

3. The system (200) of claim 1, wherein the second flow (208) is sub-atmospheric steam.

4. The system (200) of claim 3, wherein a pressure within the pressure vessel (202) during the desorption cycle is at or below 0.5 bar absolute.

5. The system (200) of claim 4, wherein a steam injector (310) is used to maintain the sub- atmospheric pressures within the containment vessel (202).

6. The system (200) of claim 3, wherein the temperature within the pressure vessel (202) during the desorption phase is at or below 90 degrees Celsius.

7. The system (200) of claim 1, wherein the containment vessel (212) is a piping circuit designed to direct the captured carbon dioxide gas to a subsequent process.Docket No. 2023PF12288 8. A method for capturing carbon dioxide from a CO2 containing gas comprising the steps of: configuring a pressure vessel (202) to receive a first flow (206), a second flow (208) and discharge a combined third flow (308), installing a sorbent filter (706) in the pressure vessel (202) and configuring the sorbent filter (706) to filter the first flow (204) during an absorption cycle, continuing the absorption cycle until the sorbent filter (706) has absorbed a predetermined level of CO2, sealing the pressure vessel (202) prior to the initiation of a desorption cycle with a plurality of lids (602) configured to bring the pressure vessel (202) in fluid communication with a plurality of line (222), valves (218) and pumps (214), configuring a heat source (204) to heat the second flow (208) prior to entering the pressure vessel (202), flowing the second flow (208) into the pressure vessel (202) during the desorption cycle, discharging the third flow (224) from the pressure vessel (202) at the end of the desorption cycle, configuring a heat exchanger (300) to cool the combined third flow (224) after it is discharged by the pressure vessel (202), separating CO2 from the combined third flow (224), configuring a containment vessel (212) to receive and store a flow of carbon dioxide gas during a collection cycle, wherein the desorption cycle is performed at sub-atmospheric pressure.

9. The method of claim 8, wherein the first flow (206) is atmospheric air.

10. The method of claim 8, wherein the second flow (208) is steam at sub atmospheric pressure.

11. The method of claim 8, wherein the containment vessel (212) is a piping circuit designed to direct the captured carbon dioxide gas to a subsequent process.

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