Gas turbine integration with solvent direct air capture system

Abstract

A power generation system includes a gas turbine engine configured to discharge an exhaust gas and a direct air capture (DAC) system coupled to the gas turbine engine. The DAC system includes a gas-liquid contactor and a regeneration system. The regeneration system includes a causticizer operably coupled to the gas-liquid contactor, a slaker operably coupled to the causticizer, and a calciner operably coupled to each of the causticizer and the slaker and in thermal communication with the exhaust gas.

Description

700906-WO-l(17851-1501)GAS TURBINE INTEGRATION WITH SOLVENT DIRECT AIR CAPTURE SYSTEMTECHNICAL FIELD

[0001] The disclosure relates generally to gas separation, and more particularly, to direct air capture systems and methods for capturing carbon dioxide using exhaust gases from a gas turbine system.BACKGROUND

[0002] Direct air capture (DAC) is an advancing technology for extracting carbon dioxide from ambient air for storage and / or utilization for other processes. With DAC, ambient air flows through a solvent or sorbent and carbon dioxide is captured from the ambient air. The captured carbon dioxide is desorbed through the application of energy, such as heat. Within at least some known systems, significant heat may be required to regenerate the DAC system, resulting in inefficiencies, added complexity, and increased costs of using the DAC as compared to gas turbine systems that forego the use of a DAC system. External heat sources may be used to regenerate the DAC system, however, the use of increased fossil fuel emissions to extract a greater percentage of carbon dioxide is counterintuitive to achieving net neutrality or a reduction in carbon dioxide concentrations in Earth’s atmosphere.

[0003] Accordingly, it would be desirable to utilize heat generated by the gas turbine system to regenerate the DAC system and to facilitate increasing the efficiency of DAC system, reducing the complexity of the DAC system, and reducing the overall costs associated with using the DAC system.SUMMARY

[0004] In one aspect, a gas generation system includes a gas turbine engine configured to discharge an exhaust gas and a direct air capture (DAC) system coupled to the gas turbine engine. The DAC system includes a gas-liquid contactor and a regeneration system. The regeneration system includes a causticizer operably coupled to the gas-liquid contactor, a slaker operably coupled to the causticizer, and a calciner operably coupled to each of the causticizer and the slaker and in thermal communication with the exhaust gas.

[0005] In another aspect, a direct air capture (DAC) system including a gas-liquid contactor and a regeneration system. The regeneration system includes a causticizer operably coupled700906-WO-l (17851-1501) to the gas-liquid contactor, a slaker operably coupled to the causticizer, and a postcombustion heating chamber in flow communication wi th an exhaust gas discharged from a gas turbine engine. The post-combustion heating chamber is operably coupled to each of the causticizer and the slaker and includes a calciner positioned within an interior portion of the post-combustion heating chamber and in thermal communication with the exhaust gas. The post-combustion heating chamber also includes a combustor in thermal communication with exhaust gases received within the post-combustion heating chamber. The combustor is configured to heat the exhaust gases received within the post-combustion heating chamber from a first temperature to a second temperature that causes desorption of carbon dioxide within the calciner.

[0006] In yet another aspect, a method of operating a direct air capture (DAC) system includes channeling a fluid to a gas turbine engine, compressing, via the gas turbine engine, the fluid channeled to the gas turbine engine, discharging exhaust gases from the gas turbine engine, channeling a fluid to a gas-liquid contactor of the DAC system, absorbing, via a first solution retained in the gas-liquid contactor, carbon dioxide from the fluid channeled to the gas-liquid contactor to form a second solution, channeling the second solution to a causticizer of the DAC system to form calcium carbonate and the first solution, channeling the calcium carbonate from the causticizer to a calciner positioned within an interior portion of a postcombustion heating chamber, channeling exhaust gases from the gas turbine engine to the post-combustion heating chamber, and heating, via supplementary' firing, the exhaust gas received within the post-combustion heating chamber to heat the calciner and desorb carbon dioxide retained within the calcium carbonate received by the calciner.

[0007] The illustrative aspects of the present disclosure are designed to solve the problems herein described and / or other problems not discussed.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] These and other features of this disclosure will be more readily understood from the following detailed description of the various aspects of the disclosure taken in conjunction with the accompanying drawings that depict various embodiments of the disclosure, in which:

[0009] FIG. 1 is a schematic view of an exemplary power generation system including a combined cycle power plant;700906-WO-l (17851-1501)

[0010] FIG. 2 is a schematic view of a direct air capture system that may be used with the combined cycle power plant shown in FIG. 1;

[0011] FIG. 3 is a schematic view' of an exemplary combined cycle pow er plant including the direct air capture system shown in FIG. 2;

[0012] FIG. 4 is a schematic view of another exemplary combined cycle power plant including the direct air capture system shown in FIG. 2;

[0013] FIG. 5 is a schematic view' of yet another exemplary combined cycle power plant including the direct air capture system shown in FIG. 2;

[0014] FIG. 6 is a schematic view of an exemplar}' control system that may be used with the combined cycle power plant shown in FIG. 1;

[0015] FIG. 7A is a flow' diagram of an exemplary' method that may be implemented to control a direct air capture system;

[0016] FIG. 7B is a continuation of the flow diagram of FIG. 7A; and

[0017] FIG. 7C is a continuation of the flow' diagram of FIG. 7B.

[0018] It is noted that the drawings of the disclosure are not to scale. The drawings are intended to depict only typical aspects of the disclosure, and therefore should not be considered as limiting the scope of the disclosure. In the drawings, like numbering represents like elements between the drawings.DETAILED DESCRIPTION

[0019] In accordance with the disclosure, a direct air capture (DAC) system may be integrated and / or otherwise operably coupled to receive the exhaust gas flow from a gas turbine engine. As described herein, utilizing the heat of the exhaust gases, coupled w ith supplementary firing, can facilitate raising the temperature of a calciner of the DAC system more efficiently as compared to utilizing an air separation unit (ASU) and / or an oxyfuel boiler. In this manner, the calciner of the DAC system is The exhaust gases heat the calciner, and thus facilitate reducing an amount of energy needed that would be required to raise the temperature of the calciner using external heat sources. A combustor is positioned within, or is in thermal communication with, the exhaust gases received within the calciner. The combustor is fluidly coupled to and / or in flow' communication with a fuel source, such as natural gas, which when mixed with the exhaust gases and combusted, is utilized as supplementary firing to raise the temperature of the exhaust gases to a temperature required to desorb carbon dioxide within the calciner. As can be appreciated, the elimination of the700906-WO-l (17851-1501)ASU and / or oxyfuel boiler facilitates reducing the overall costs and complexity of the DAC system.

[0020] Although generally described as omitting the ASU and / or oxyfuel boiler, it is envisioned that the DAC system may use oxygen siphoned or otherwise diverted from the ASU to enable the combustor to operate using oxyfuel. In this manner, the efficiency of the DAC system can be increased as compared to systems that only supply natural gas to the combustor.

[0021] In some embodiments, the exhaust gases flowing through the post-combustion heating chamber may be channeled to a post-combustion carbon capture system to facilitate desorbing or otherwise capturing carbon dioxide from the exhaust gases. It is envisioned that the desorbed carbon dioxide may be channeled to a storage tank and / or to another downstream component, or may be channeled to a gas-liquid contactor of the DAC system to facilitate increasing a yield of carbon dioxide captured by the DAC system. In embodiments, the exhaust gas flowing through the post-combustion heating chamber may be channeled to a heat recovery steam generator (HRSG) of a steam turbine system to facilitate increasing an efficiency of a combined cycle power plant. .

[0022] Unless otherwise indicated, approximating language, such as ‘"generally / ’ ‘‘substantially,” and “about,” as used herein indicates that the term so modified may apply to only an approximate degree, as would be recognized by one of ordinary skill in the art, rather than to an absolute or perfect degree. Accordingly, a value modified by a term or terms such as “about," “approximately,” and “substantially” is not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Additionally, unless otherwise indicated, the terms “first,” “second,” etc. are used herein merely as labels, and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Moreover, reference to, for example, a “second” item does not require or preclude the existence of, for example, a “first” or lower-numbered item or a “third” or higher-numbered item.

[0023] In addition, several descriptive terms may be used regularly herein, and it should prove helpful to define these terms at the onset of this section. These terms and their definitions, unless stated otherwise, are as follows. As used herein, “downstream” and “upstream” are terms that indicate a direction relative to the flow of a fluid, such as the700906-WO-l (17851-1501) working fluid through the turbine engine or, for example, the flow of air through the combustor or coolant through one of the turbine's component systems. The term “downstream” corresponds to the direction of flow of the fluid, and the term “upstream” refers to the direction opposite to the flow. The terms “forward” and “aft,” without any further specificity, refer to directions, with “forward” referring to the front or compressor end of the engine, and “aft” referring to the rearward or turbine end of the engine. It is often required to describe parts that are at differing radial positions with regard to a center axis. The term “radial” refers to movement or position perpendicular to an axis. In cases such as this, if a first component resides closer to the axis than a second component, it will be stated herein that the first component is “radially inward” or “inboard” of the second component. If, on the other hand, the first component resides further from the axis than the second component, it may be stated herein that the first component is “radially outward” or “outboard” of the second component. The term “axial” refers to movement or position parallel to an axis. Finally, the term “circumferential” refers to movement or position around an axis. It will be appreciated that such terms may be applied in relation to the center axis of the turbine.

[0024] Referring now to the drawings, FIG. 1 illustrates a schematic depiction of an exemplary power generation system 10 according to various embodiments of the disclosure. In the exemplary embodiment, the system 10 includes a combined cycle power plant 12 including a gas turbine system 14 and a steam turbine system 60. In some embodiments, the gas turbine system 14 includes a gas turbine engine 16, which in some embodiments, may be operably coupled to a control system or to a controller 18. In the exemplary embodiment, the gas turbine engine 16 is coupled to a load 28 and includes a fluid intake section 20, a compressor section 22, a combustor section 24, a turbine section 26, and an exhaust section 30. The fluid intake section 20 draws or otherwise receives a fluid 32 to be compressed by the compressor section 22. It is envisioned that the fluid 32 may be any fluid or any mixture of fluids embodying any state, such as a liquid or a gas, and / or having any characteristic, such as pressure, temperature, humidity, carbon dioxide concentration, etc. In one nonlimiting embodiment, the fluid 32 is ambient air surrounding or otherwise in fluid and / or flow communication with the fluid intake section 20.700906-WO-l (17851-1501)

[0025] In the exemplary embodiment, the compressor section 22 is in fluid and / or flow communication with the fluid intake section 20 and is operably coupled to a compressor shaft 34 rotatably supported within the gas turbine engine 16. As can be appreciated, during operation, the compressor section 22 compresses fluid 32 flowing through the compressor section 22 and delivers a compressed fluid 36 to the combustor section 24. The combustor section 24 is in flow communication with the compressor section 22 and includes one or more combustors (not shown), each of which, in embodiments, includes one or more fuel nozzles (not shown). It is envisioned that the combustor section 24 may include any number of combustors, which in embodiments, may be circumferentially spaced about one another and about a longitudinal axis A-A of the gas turbine engine 16, without departing from the scope of the invention. The fuel nozzles each receive compressed fluid 36 from the compressor section 22. and fuel 42 from one or more fuel supply systems 44 coupled to the fuel nozzles. As can be appreciated, the fuel nozzles mix the compressed fluid 36 and the fuel 42 and ignite or otherwise combust the resulting mixture of compressed fluid 36 and fuel 42 to create hot combustion gases 46 that are exhausted or otherwise discharged from each combustor and received by the turbine section 26. It is envisioned that the fuel 42 may be any suitable fuel for use with the system 10 without departing from the scope of the invention. In one embodiment, the fuel 42 may be natural gas. In another non-limiting embodiment, the fuel 42 may be Hydrogen gas (H2). It is contemplated that when utilizing Hydrogen gas, the system 10 may be a negative emissions system.

[0026] With continued reference to FIG. 1, the turbine section 26 may include one or more turbine stages (not shown) operably coupled to a turbine shaft 48 that is rotatably supported within the turbine section 26. As can be appreciated, as hot combustion gases 46 flow through the turbine section 26, the hot combustion gases 46 expand and effectuate rotation of the turbine stages, w hich in turn, effectuates a corresponding rotation of the turbine shaft 48. In some embodiments, the compressor shaft 34 may be operably coupled to the turbine shaft 48. In this manner, rotation of the turbine shaft 48 effectuates a corresponding rotation of the compressor shaft 34 to compress fluid 32 flowing through the compressor section 22. It is envisioned that the load 28 coupled to the turbine section 26 may be, but is not limited to only being, an electrical generator, a machine, and / or combinations thereof. Although generally illustrated as being adjacent to the turbine section 26 of the gas turbine engine 16, it is contemplated that the load 28 may be at any relative location relative to the turbine700906-WO-l (17851-1501) section 26, such as adjacent to the compressor section 22 of the gas turbine engine 1 , without departing from the scope of the invention.

[0027] The exhaust section 30 may include an exhaust duct, exhaust treatment equipment, silencers, etc., and / or combinations thereof. In one non-limiting embodiment, the exhaust section 30 may include, and / or may direct, a flow of exhaust gas 50 from the turbine section 26 through a heat exchanger and / or cooling system, such as a heat recovery steam generator (HRSG) 80 for transferring heat from the exhaust gas 50 to a fluid. In some embodiments, the fluid may be water that is used to generate steam used to drive a steam turbine of the steam turbine system 60. In some embodiments, the system 10 may include one or more coolers (not shown), such as a direct contact cooler, oriented to spray a fluid directly onto the exhaust gas 50 to effectuate cooling of the exhaust gas 50.

[0028] Continuing with FIG. 1, the steam turbine system 60 may include one or more of a high-pressure portion 62, an intermediate-pressure portion 64. and a low-pressure portion 66. In one non-limiting embodiment, each of the high-pressure portion 62, the intermediatepressure portion 64, and the low-pressure portion 66 are rotatably coupled via a rotatable shaft 68. In this manner, the high-pressure portion 62, the intermediate-pressure portion 64, and the low-pressure portion 66 cooperate to effectuate rotation of the rotatable shaft 68 and produce mechanical work and / or to drive an additional component of the steam turbine system 60. In embodiments, the rotatable shaft 68 of the steam turbine system 60 is coupled to and / or drives one or more external components, such as a generator 70 to generate power and / or produce a load.

[0029] Although generally illustrated as including a dual-shaft configuration, where two separate generators or loads 28 and 70 are utilized, it is envisioned that the gas turbine system 14 and the steam turbine system 60 may share a single shaft, and in turn, share a single generator without departing from the scope of the invention. Additionally, although generally illustrated as having only a single gas turbine system 14 and a single steam turbine system 60, it is envisioned that the combined cycle power plant 12 may include any number of gas turbine systems 14 and / or steam turbine system 60 that generate an operation load and / or power output without departing from the scope of the invention.

[0030] With continued reference to FIG. 1, the system 10 may include an HRSG 80 fluidly coupled to and / or in flow communication with the steam turbine system 60 (e.g., with the high-pressure portion 62, the intermediate-pressure portion 64, and the low-pressure portion700906-WO-l (17851-1501)66) and the gas turbine system 14. In embodiments, the HRSG 80 is coupled in flow communication with the steam turbine system 60 via one or more exhaust conduits 82 to receive exhaust fluid (e.g, steam) from the steam turbine system 60, as well as to provide steam to the portions of the steam turbine system 60 via one or more supply conduits 84. In one non-limiting embodiment, the HRSG 80 may be in flow communication with the gas turbine system 14 via one or more exhaust channels 86 coupled to and / or in fluid communication with the turbine section 26. In this manner, the exhaust channel 86 provides exhaust fluid (e.g.. gas) from the gas turbine system 14 to the HRSG 80 to be utilized in generating and / or heating steam for the steam turbine system 60. It is envisioned that the exhaust gases 50, or a portion of the exhaust gases 50, may be exhausted and / or released from a stack 88 of the HRSG 80 into the atmosphere and / or from the combined cycle power plant 12.

[0031] With additional reference to FIG. 2, the combined cycle power plant 12 may include a Direct Air Capture (DAC) system 100 and a post-combustion carbon capture system 120. Although generally described as being a solvent-based DAC, it is envisioned that the DAC 100 may be any other suitable DAC system without departing from the scope of the present disclosure. In the exemplary embodiment, the DAC 100 includes a gas-liquid contactor 102 and a regeneration system 104 operably coupled to the gas-liquid contactor. The regeneration system 104 includes a causticizer 106, a calciner 108, a post-combustion heating chamber 110, and a slaker 112.

[0032] The gas-liquid contactor 102 may be any suitable gas-liquid contactor, and in embodiments, may be an air-liquid contactor. The contactor 102 retains an aqueous solution, which in embodiments may be an alkali solution such as potassium hydroxide (KOH), sodium hydroxide (NaOH), Lye, etc. and / or combinations thereof. In one non-limiting embodiment, the aqueous solution is 2KOH. The contactor 102 fluidly couples ambient air 202 to the alkali solution, which scrubs or otherwise absorbs carbon dioxide (CO2) from the ambient air 202 and forms a second aqueous solution 204 containing water and potassium carbonate (K2CO3). In some embodiments, ambient air 202 entering the contactor 102 contains approximately 400 ppm (0.04%) CO2 and the contactor adsorbs approximately 75% of the CO2 contained in the ambient air.700906-WO-l (17851-1501)

[0033] It is envisioned that the contactor 102 may include a fan or other suitable air movement component (not shown) to effectuate movement of the ambient air 202 through the contactor 102. In one non-limiting embodiment, the flowrate of ambient air 202 through the contactor is approximately 1.5 m / s. The scrubbed or otherwise filtered air 206 is exhausted to the atmosphere, or in some embodiments may be transferred to one or more downstream components of the system 10. The second aqueous solution 204 is provided to the causticizer 106 for further processing. In the exemplary embodiment, the contactor 102 filters or otherwise separates the water from the second aqueous solution of K2CO3. which may be transferred or otherwise provided to the slaker 1 12 along with, or separate from, the second aqueous solution, although it is contemplated that the water may be provided to the causticizer 106 without departing from the scope of the disclosure. Although only described as having one contactor 102. it is envisioned that the DAC 100 may include any number of contactors 102. which may be the same or different type of contactors 102. depending upon the design needs of the DAC 100.

[0034] The causticizer 106 is fluidly coupled to or in flow communication with the contactor 102. The causticizer 106 receives the second aqueous solution of K2CO3 and effectuates a reaction forming calcium carbonate (CaCOs) precipitate and K2OH. In embodiments where the water is provided to the causticizer 106, the reaction within the causticizer 106 forms a calcium carbonate (CaCOs) slurry. It is envisioned that the causticizer 106 may retain any suitable compound for forming CaCOs, and in one non-limiting embodiment, the causticizer 106 retains calcium hydroxide (Ca(OH)2). The K20H formed within the causticizer 106 is returned to the air contactor 102.

[0035] With continued reference to FIG. 2, the calciner 108 is fluidly coupled to or in flow communication with each of the causticizer 106 and the slaker 112. The calciner 108 receives the CaCOs formed by the causticizer 106, where it is heated to separate the CO2 from the CaCOs and form solid calcium oxide (CaO) and a high-purity CO2 gas. As can be appreciated, significant heat and energy is transferred to the CaCO3 to separate the CaO from the CO2 within the CaCOs. In embodiments, the CaCOs is heated to a temperature of approximately 900 °C. In this manner, an external heat source (not shown) is often needed to provide the heat and energy needed to raise the temperature of the CaCOs to 900 °C. In embodiments, the calciner 108 is operably coupled to and / or in thermal communication with an oxyfuel boiler (not shown) and an air separation unit (ASU) (not shown). As can be700906-WO-l (17851-1501) appreciated, the oxyfuel boiler and ASU contribute considerable cost and complexity to the system 10 and consume considerable energy when heating the CaCCh received by the calciner 108.

[0036] In the exemplary embodiment, the regeneration system 104 does not include an oxyfuel boiler and / or ASU, or an oxyfuel boiler and / or the ASU of system 10 is not utilized to heat the calciner 108. In lieu of utilizing the oxyfuel boiler and / or the ASU, the calciner 108 is positioned within a post-combustion heating chamber 110. The post-combustion heating chamber 110 is fluidly coupled to or in flow communication with the exhaust gases 50 discharged from the gas turbine system 14. In this manner, the exhaust gases 50. or at least a portion of the exhaust gases 50, may flow through the post-combustion heating chamber 110 and heat the CaCCT retained within the calciner 108. As can be appreciated, although the exhaust gases 50 may be at a temperature that is lower than the temperature needed to form CaO. the exhaust gases 50 provide a heat source that necessitates less energy and / or heating of the calciner 108 as compared to using an oxyfuel boiler and / or an ASU, and thus facilitate increasing the efficiency of the process of separating the CaO and CO2 from the CaCOs retained within the calciner 108.

[0037] In the exemplary embodiment, the exhaust gases 50 are received by the postcombustion heating chamber 110 at a temperature of approximately 600 °C. The postcombustion heating chamber 110 is fluidly coupled to or in flow communication with the fuel supply system 44. which delivers fuel 42 to the post-combustion heating chamber 110 wherein it is combusted in a combustor 11 to provide supplementary heating to the calciner 108. The combustion of the fuel 42 heats or otherwise effectuates an increase in temperature of the exhaust gases 50 from approximately 600 °C to approximately 900 °C. which in turn, heats or otherwise increases the temperature of the calciner 108 to form the CaO and CO2. The exhaust gases 50 flowing through the post-combustion heating chamber 110 are transferred or otherwise provided to the HRSG 80 and thereafter, to the post-combustion carbon capture system 120. As will be described in further detail hereinbelow, the exhaust gases 50 include concentrations of CO2, which is scrubbed or otherwise separated from the exhaust gases 50 by the post-combustion carbon capture system 120. The CaO formed in the calciner 108 is transferred or otherwise provided to the slaker 112.700906-WO-l (17851-1501)

[0038] The slaker 1 12 is fluidly coupled to or in flow communication with the causticizer 106, the calciner 108, and in embodiments, with the contactor 102. The slaker 112 receives solid calcium oxide (CaO) from the calciner 108 and water from the contactor 102 and / or the causticizer 106. The CaO and water react within the slaker 112 to form or otherwise regenerate Ca(OH)2, which is returned to the causticizer 106 where it is reused to form the CaCOs precipitate.

[0039] With reference to FIG. 3, the post-combustion carbon capture system 120 is fluidly coupled to and / or in flow communication with the HRSG 80 and / or the post-combustion heating chamber 110. The post-combustion carbon capture system 120 includes an absorber 122 fluidly coupled and / or in fluid communication with the exhaust gas 50 discharged from the post-combustion heating chamber 110 or the HRSG 80. The absorber 122 retains a solvent that absorbs CO2 from the exhaust gas 50. It is envisioned that the solvent may be any suitable solvent, and in embodiments, may be is 2K0H without departing from the scope of the disclosure. The absorber 122 is fluidly coupled to and / or in flow communication with a desorber 124, which receives the solvent-CCh mixture. The desorber 124 heats or otherwise increases the temperature of the solvent-CCh mixture to separate the CO2 from the mixture. In embodiments, the desorber 124 is fluidly coupled to and / or in flow communication with the steam turbine system 60 and / or the HRSG 80. The steam 61 received by the desorber 124 is used to heat the solvent-CCh mixture and separate CO2 from the solvent-CCh mixture.

[0040] In one non-limiting embodiment, the post-combustion carbon capture system 120 includes a reboiler (not shown) fluidly coupled to and / or in flow communication with each of the steam turbine system 60 and the desorber 124. In this manner, the solvent-CCh mixture is circulated within the reboiler which is heated by the steam 61 received from the steam turbine system 60 to form a solvent-CCh mixture vapor. The solvent-CCh mixture vapor is returned to the desorber 124 to increase an amount of CO2 separated from the solvent-CCh mixture as compared to a system that does not incorporate the use of a reboiler. The separated CO2 is discharged or otherwise exhausted from the desorber 124, where it is transferred or otherwise provided to a storage tank (not shown) and / or one or more downstream components of the system 10. The solvent that has had CO2 stripped or otherwise filtered by the desorber 124 is returned to the absorber 122.700906-WO-l (17851-1501)

[0041] Turning to FIG. 4, it is envisioned that the post-combustion carbon capture system 120 may be integrated into the DAC 100. In this manner, the steam discharged from the steam turbine system 60 is transferred to and / or provided to the DAC 100 for regeneration of the solvent and / or sorbent. The CO2 separated from the sol \ ent-CO2 mixture is transferred to or otherwise provided to the contactor 102 where it is mixed with the ambient air drawn into the contactor 102 or otherwise supplements the ambient air draw into the contactor 102. As can be appreciated, by transferring the CO2 separated in the desorber 124 to the contactor 102, no CO2 is discharged to the atmosphere. In some embodiments, the CO2 concentration of the exhaust gas 50 is approximately 5%. The remaining K2CO3 of the solvent-CCh mixture is transferred to or otherwise transported to the causticizer 106.

[0042] With reference to FIG. 5, it is contemplated that the DAC system 100 may utilize an ASU 130 to provide oxygen O2 as a supplement to the fuel 42. In this manner, the ASU 130 is fluidly coupled to and / or in flow communication with the post-combustion heating chamber 1 10. Oxygen O2 separated from air entering the ASU 130 is channeled to the combustor 116 of the post-combustion heating chamber 110 to supplement and / or replace the fuel 42 (which may be. for example, natural gas) to heat the calciner 108 to 900 °C. As can be appreciated, the oxygen O2 provided to the combustor 116 of the post-combustion heating chamber 110 by the ASU 130 facilitates increasing an efficiency of the DAC 100 compared to utilizing only the fuel 42 to heat the calciner 108 to 900 °C. It is contemplated that the ASU 130 may be a part of a combined cycle oxy-fuel gas turbine, where a portion of the oxygen O2 separated by the ASU 130 is channeled to the combustor section 24 of the gas turbine engine 16 and a portion of the oxygen O2 separated by the ASU 130 is channeled to the combustor 116 of the post-combustion heating chamber 110.

[0043] Turning to FIG. 6, in the exemplary embodiment, the control system 18 includes a computer 600, which in embodiments, may be coupled to a display 602 that displays one or more user interfaces 604. The control system 18 may be a desktop computer or a tower configuration with the display, may be a laptop computer, may be integrated into a system control panel, etc. The control system 18 includes a processor 606 which executes software stored in a memory' 608. The memory 608 may store data or other information regarding the gas turbine system 14. In addition, the memory 608 may store one or more algorithms 610 and / or software applications 612 to be executed by the processor 606.700906-WO-l (17851-1501)

[0044] In the exemplary embodiment, a network interface 614 enables the control system 18 to communicate with a variety of other devices and systems via the Internet. The network interface 614 may connect the control system 18 to the Internet via a wired or wireless connection. Additionally, or alternatively, the communication may be via an ad-hoc Bluetooth " or wireless network enabling communication with a wide-area network (WAN) and / or a local area network (LAN). The network interface 614 may connect to the Internet via on or more gateway, routers, and network address translation (NAT) devices. The network interface 614 may communicate with a cloud storage system 616, in which further data and / or information associated with the system 10 may be stored. The cloud storage system 616 may be remote from or on the premises of a control room. An input module 618 receives inputs from an input device such as, for example, a keyboard, a mouse, or voice commands. An output module 620 connects the processor 606 and the memory 608 to a variety of output devices, such as, for example, the display 602. In some embodiments, the control system 18 may include its own display (not shown), which may be a touchscreen display.

[0045] With reference to FIG. 7, a method of operating a DAC system is illustrated and generally identified by reference numeral 700. Initially, a fluid, such as air, is channeled 702 to a gas turbine engine. The fluid flowing through the gas turbine engine is compressed 704 by the gas turbine engine and discharged 706 as exhaust gas. The exhaust gases are channeled 708 to a post-combustion heating chamber retaining a calciner of the DAC system. In parallel, a fluid, such as air, is channeled 710 to an air contactor of the DAC system retaining a first solution. The first solution retained within the contactor absorbs 712 CO2 from the fluid to form a second solution and water. The water is channeled 714 to a slaker of the DAC system. The second solution is channeled 716 to a causticizer of the DAC system retaining calcium hydroxide to form calcium carbonate and the first solution. The first solution is channeled 718 to the contactor to replenish the first solution retained within the contactor. The calcium carbonate formed within the causticizer is channeled 720 to the calciner, where the exhaust gas received within the post-combustion heating chamber is heated 722, via supplementary firing within the post-combustion heating chamber, from a first temperature to second temperature for desorbing 724 CO2 from calcium carbonate received within the calciner.700906-WO-l (17851-1501)

[0046] The desorbed CO2 is channeled 726 to a storage tank and / or downstream component of the DAC system and solid calcium oxide formed by desorbing CO2 from the calcium carbonate is channeled 728 to a slaker of the DAC system, where the calcium oxide and water react to form 730 calcium hydroxide. The calcium hydroxide formed within the slaker is channeled 732 to the causticizer to replenish the supply of calcium hydroxide retained within the causticizer. The exhaust gases flowing through the post-combustion heating chamber are channeled 734 to a HRSG to heat steam used in a steam turbine system. The exhaust gases flowing through the HRSG are channeled 736 to an absorber of a postcombustion carbon capture system. The absorber receives the exhaust gases and absorbs 738 CO2 from the exhaust gases to form a third solution. The third solution is channeled 740 to a desorber of the post-combustion carbon capture system.

[0047] The third solution is heated 742 within the desorber using steam received from the steam turbine to separate CO2 from the third solution. The CO2 separated from the third solution is channeled 744 to a storage tank or one or more downstream components of the system. Optionally, the CO2 separated from the third solution is channeled 746 to the contactor of the DAC system to be mixed with the fluid received by the contactor. Optionally, the second solution formed by separating the CO2 from the third solution is channeled 748 to the DAC system. Optionally, the steam exhausted from the steam turbine system is channeled 750 to the DAC system for regeneration of the first solution. Optionally, the oxygen is channeled 752 from an ASU to the post-combustion heating chamber to provide supplementary firing and heat the calciner from the first temperature to the second temperature.

[0048] As can be appreciated, the above-described method 700 may be repeated as many times as necessary7and the method 700 may be performed in any order without departing from the scope of the present invention.

[0049] Although the description of computer-readable media contained herein refers to solid-state storage, it should be appreciated by those skilled in the art that computer-readable storage media can be any available media that can be accessed by the processor 606. That is, computer readable storage media may include non-transitory, volatile, and non-volatile, removable and non-removable media implemented in any method or technology for storage of information such as for example, computer readable instructions, data structures, program modules or other data. For example, computer-readable storage media may include RAM,700906-WO-l (17851-1501)ROM, EPROM, EEPROM, flash memory or other solid-state memory technology, CD- ROM, DVD, Blu-Ray or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which may be used to store the desired information, and which may be accessed by the control system 18.

[0050] The system according to exemplary embodiments as described herein facilitates increasing an efficiency of a solvent-based DAC system by positioning a calciner of the DAC system in the exhaust gas path of a gas turbine engine. Placing the calciner in the exhaust gas path of the gas turbine engine utilizes energy stored in the exhaust gases to heat the calciner to the temperature necessary to regenerate CO2 from CaCCE As such, an ASU and / or oxy fuel boiler may be omitted from the DAC system, thus facilitating reducing complexity and increasing efficiency of the DAC system. The calciner is positioned within a post-combustion heating chamber that is in flow communication with the exhaust gas path. The exhaust gas in thermal communication with the calciner heats the calciner to a temperature of approximately 600 °C. Supplementary firing is used to increase the temperature of the exhaust gas received within the post-combustion heating chamber to 900 °C. As can be appreciated, the energy transferred from the exhaust gas to the calciner facilitates reducing or otherwise eliminating the need for an ASU and / or oxyfuel boiler to raise the temperature of the calciner from 600 °C to 900 °C. In embodiments, the DAC system may be operably coupled to a post-combustion carbon capture system to absorb CO2 from the exhaust gases and to facilitate absorbing additional CO2 as compared to using the DAC system alone.

[0051] The above description is meant to be exemplary only, and one skilled in the art will recognize that changes may be made to the embodiments described without departing from the scope of the invention disclosed. Modifications, which fall within the scope of the present invention, will be apparent to those skilled in the art, in light of a review of this disclosure, and such modifications are intended to fall within the appended claims. The systems described herein are not limited to the specific embodiments described herein, but rather portions of the various systems may be utilized independently and separately from other systems described herein.

[0052] Although specific features of vanous embodiments of the invention may be shown in some drawings and not in others, this is for convenience only. Moreover, references to “one embodiment” in the above description are not intended to be interpreted as excluding700906-WO-l (17851-1501) the existence of additional embodiments that also incorporate the recited features. In accordance wi th the principles of the invention, any feature of a drawing may be referenced and / or claimed in combination with any feature of any other drawing. Further aspects of the invention are provided by the subject matter of the following clauses:

[0053] A power generation system includes a gas turbine engine configured to discharge an exhaust gas and a direct air capture (DAC) system coupled to the gas turbine engine. The DAC system includes a gas-liquid contactor and a regeneration system. The regeneration system includes a causticizer operably coupled to the gas-liquid contactor, a slaker operably coupled to the causticizer, and a calciner operably coupled to each of the causticizer and the slaker and in thermal communication with the exhaust gas.

[0054] The system in accordance with any of the preceding clauses, wherein the regeneration system may include a post-combustion heating chamber in flow communication with the exhaust gases discharged from the gas turbine engine, wherein the calciner is positioned within an interior portion of the post-combustion heating chamber.

[0055] The system in accordance with any of the preceding clauses, wherein the postcombustion heating chamber may include a combustor for heating the exhaust gases received within the post-combustion heating chamber from a first temperature to a second temperature that causes desorption of carbon dioxide within the calciner.

[0056] The system in accordance with any of the preceding clauses, wherein the combustor is operable using natural gas.

[0057] The system in accordance with any of the preceding clauses, wherein the system may include an air separation unit (ASU) in flow communication with the combustor of the postcombustion heating chamber, wherein the ASU is configured to channel oxygen to the combustor of the post-combustion heating chamber.

[0058] The system in accordance with any of the preceding clauses, wherein the system may include a post-combustion carbon capture system in flow communication with the exhaust gases discharged from the gas turbine engine.

[0059] The system in accordance with any of the preceding clauses, wherein carbon dioxide absorbed from the exhaust gases may be channeled to the gas-liquid contactor.

[0060] The system in accordance with any of the preceding clauses, wherein a solvent formed by desorbing the carbon dioxide within the post-combustion carbon capture system may be channeled to the DAC system.700906-WO-l (17851-1501)

[0061] The system in accordance with any of the preceding clauses, wherein the system may include a steam turbine system including a heat recovery' steam generator (HRSG) in flow communication with the exhaust gas and a steam turbine operably coupled to the HRSG.

[0062] The system in accordance with any of the preceding clauses, wherein the steam turbine system may be in flow communication with the DAC system.

[0063] In another aspect, a direct air capture (DAC) system includes a gas-liquid contactor and a regeneration system. The regeneration system includes a causticizer operably coupled to the gas-liquid contactor, a slaker operably coupled to the causticizer, and a postcombustion heating chamber in flow communication with an exhaust gas discharged from a gas turbine engine and operably coupled to each of the causticizer and the slaker. The postcombustion heating chamber includes a calciner positioned within an interior portion of the post-combustion heating chamber and in thermal communication with the exhaust gas, and a combustor in thermal communication with exhaust gases received within the postcombustion heating chamber. The combustor heats the exhaust gases received within the post-combustion heating chamber from a first temperature to a second temperature that causes desorption of carbon dioxide within the calciner.

[0064] The DAC system in accordance with any of the preceding clauses, wherein the gasliquid contactor may be in flow communication with a post-combustion carbon capture system. Wherein the desorbed carbon dioxide is channeled from the post-combustion carbon capture system to the gas-liquid contactor.

[0065] The DAC system in accordance with any of the preceding clauses, wherein the exhaust gases flowing within the post-combustion heating chamber may be channeled to a heat recovery' steam generator.

[0066] The DAC system in accordance with any of the preceding clauses, wherein the combustor may be in flow communication with an air separation unit (ASU), wherein the ASU is configured to channel oxygen to the combustor of the post-combustion heating chamber.

[0067] The DAC system in accordance with any of the preceding clauses, wherein the exhaust gases flowing within the post-combustion heating chamber may be channeled to a post-combustion carbon capture system.700906-WO-l (17851-1501)

[0068] In yet another aspect, a method of operating a direct air capture (DAC) system includes channeling a fluid to a gas turbine engine, compressing, via the gas turbine engine, the fluid channeled to the gas turbine engine, discharging exhaust gases from the gas turbine engine, channeling a fluid to a gas-liquid contactor of the DAC system, absorbing, via a first solution retained in the gas-liquid contactor, carbon dioxide from the fluid channeled to the gas-liquid contactor to form a second solution, channeling the second solution to a causticizer of the DAC system to form calcium carbonate and the first solution, channeling the calcium carbonate from the causticizer to a calciner positioned within an interior portion of a postcombustion heating chamber, channeling exhaust gases from the gas turbine to the postcombustion heating chamber, and heating, via supplementary firing, the exhaust gas received within the post-combustion heating chamber to heat the calciner and desorb carbon dioxide retained within the calcium carbonate received by the calciner.

[0069] The method in accordance with any of the preceding clauses, wherein the method may include channeling the exhaust gases received within the post-combustion heating chamber to a post-combustion carbon capture system.

[0070] The method in accordance with any of the preceding clauses, wherein the method may include absorbing carbon dioxide from the exhaust gases received by an absorber of the post-combustion carbon capture system.

[0071] The method in accordance with any of the preceding clauses, wherein the method may include channeling carbon dioxide desorbed from a third solution retained within a portion of the post-combustion carbon capture system to the gas-liquid contactor of the DAC system.

[0072] The method in accordance with any of the preceding clauses, wherein the method may include channeling the exhaust gases received within the post-combustion heating chamber to a heat recovery steam generator of a steam turbine system.

Claims

700906-WO-l(17851-1501)CLAIMSWhat is claimed is:

1. A power generation system, comprising: a gas turbine engine configured to discharge an exhaust gas; and a direct air capture (DAC) system coupled to the gas turbine engine, the DAC comprising: a gas-liquid contactor; and a regeneration system, comprising: a causticizer operably coupled to the gas-liquid contactor; a slaker operably coupled to the causticizer; and a calciner operably coupled to each of the causticizer and the slaker, and in thermal communication with the exhaust gas.

2. The system according to Claim 1, wherein the regeneration system further comprises a post-combustion heating chamber in flow communication with the exhaust gases discharged from the gas turbine engine, wherein the calciner is within an interior portion of the post-combustion heating chamber.

3. The system according to Claim 2, wherein the post-combustion heating chamber further comprises a combustor configured to heat the exhaust gases received within the post-combustion heating chamber from a first temperature to a second temperature that causes desorption of carbon dioxide within the calciner.

4. The system according to Claim 3, wherein the combustor is operable using natural gas.

5. The system according to Claim 3, further comprising an air separation unit (ASU) in flow communication with the combustor of the post-combustion heating chamber, the ASU configured to channel oxygen to the combustor of the post-combustion heating chamber.700906-WO-l(17851-1501)6. The system according to Claim 1 , further comprising a post-combustion carbon capture system in flow communication with the exhaust gases discharged from the gas turbine engine.

7. The system according to Claim 6, wherein carbon dioxide absorbed from the exhaust gases is channeled to the gas-liquid contactor.

8. The system according to Claim 7, wherein a solvent formed by desorbing the carbon dioxide within the post-combustion carbon capture system is channeled to the DAC system.

9. The system according to Claim 1, further comprising a steam turbine system comprising: a heat recovery steam generator (HRSG) in flow communication with the exhaust gas; and a steam turbine operably coupled to the HRSG.

10. The system according to Claim 9, wherein the steam turbine system is in flow communication with the DAC system.

11. A direct air capture (DAC) system, comprising: a gas-liquid contactor; and a regeneration system, comprising: a causticizer operably coupled to the gas-liquid contactor; a slaker operably coupled to the causticizer; and a post-combustion heating chamber in flow communication with an exhaust gas discharged from a gas turbine engine and operably coupled to each of the causticizer and the slaker, the post-combustion heating chamber comprising: a calciner within an interior portion of the post-combustion heating chamber and in thermal communication with the exhaust gas; and a combustor in thermal communication with exhaust gases received within the post-combustion heating chamber, the combustor configured to700906-WO-l(17851-1501) heat the exhaust gases received within the post-combustion heating chamber from a first temperature to a second temperature that causes desorption of carbon dioxide within the calciner.

12. The direct air capture system according to Claim 11, wherein the gas-liquid contactor is in flow communication with a post-combustion carbon capture system, wherein desorbed carbon dioxide is channeled from the post-combustion carbon capture system to the gas-liquid contactor.

13. The direct air capture system according to Claim 11, wherein the exhaust gases flowing within the post-combustion heating chamber are channeled to a heat recovery steam generator.

14. The direct air capture system according to Claim 11 , wherein the combustor of the post-combustion heating chamber is in flow communication with an air separation unit (ASU), wherein the ASU is configured to channel oxygen to the combustor of the post-combustion heating chamber.

15. The direct air capture system according to Claim 11, wherein the exhaust gases flowing within the post-combustion heating chamber are channeled to a postcombustion carbon capture system.

16. A method of operating a direct air capture system (DAC), comprising: channeling a fluid to a gas turbine engine; compressing, via the gas turbine engine, the fluid channeled to the gas turbine engine; discharging exhaust gases from the gas turbine engine; channeling a fluid to a gas-liquid contactor of a direct air capture (DAC) system; absorbing, via a first solution retained in the gas-liquid contactor, carbon dioxide from the fluid channeled to the gas-liquid contactor to form a second solution; channeling the second solution to a causticizer of the DAC system to form calcium carbonate and the first solution;700906-WO-l (17851-1501) channeling the calcium carbonate from the causticizer to a calciner positioned within an interior portion of a post-combustion heating chamber; channeling exhaust gases from the gas turbine engine to the post-combustion heating chamber; and heating, via supplementary firing, the exhaust gas received within the postcombustion heating chamber to heat the calciner and desorb carbon dioxide retained within the calcium carbonate received by the calciner.

17. The method according to Claim 16, further comprising channeling the exhaust gases received within the post-combustion heating chamber to a post-combustion carbon capture system.

18. The method according to Claim 17, further comprising absorbing carbon dioxide from the exhaust gases received by an absorber of the post-combustion carbon capture system.

19. The method according to Claim 18, further comprising channeling carbon dioxide desorbed from a third solution retained within a portion of the post-combustion carbon capture system to the gas-liquid contactor of the DAC system.

20. The method according to Claim 16, further comprising channeling the exhaust gases received within the post-combustion heating chamber to a heat recovery steam generator of a steam turbine system.

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