Method and system for carbon capture

Abstract

The present disclosure is related to methods and systems for reduction of carbon dioxide (CO2). In some embodiments of the present disclosure, a system comprises a preconcentrator for receiving ambient air or flue gas and converting the same into a gas stream comprising carbon dioxide (CO2) in a concentration greater than about 25 percent by volume (vol.%); an air contactor for receiving the gas stream, removing at least a portion of CO2 from the gas stream, and converting the removed CO2 into a solution comprising a carbonate having a molar ratio of carbon to alkali metal of 0.5 to 1.0; and a carbonate electrolyzer for receiving and converting the carbonate to carbon monoxide (CO) or methanol (CH3OH), where the carbonate electrolyzer comprises a single bipolar membrane.

Description

[0001] 081546.0486

[0002] 1

[0003] METHOD AND SYSTEM FOR CARBON CAPTURE

[0004] Cross-Reference To Related Application

[0005] This application claims the benefit, under 35 U.S.C. § 119(e), of U.S. Provisional Patent Application No. 63 / 733,108, filed December 12, 2024, which is incorporated herein by reference in its entirety.

[0006] Field of the Disclosure

[0007] The present disclosure is related to methods and systems for reduction of carbon dioxide (CO2).

[0008] Background of the Disclosure

[0009] Due to environmental concerns, carbon sequestration and utilization technologies have gained attention in recent years. For example, a carbon sequestration system can include devices for capture of carbon dioxide (CO2) from ambient air or a flue gas in a liquid sorbent, separating the CO2 from the liquid sorbent, and then sequestering the CO2 or using the CO2 in further chemical reaction processes. For example, the captured CO2 can be converted into products and intermediates, such as fuels or other chemicals. Example products requiring captured CO2 include eFuels and eChemicals via power-to-liquid methods, like synthesis gas (a mixture of H2 and CO), sustainable aviation fuel (SAF), renewable diesel, methanol, ethylene, ethanol, formic acid, propanol, propylene, ethane, propane, acetic acid, and others. In order to use CO2 in the further manufacture of products, the CO2 is first reduced to carbon monoxide (CO). The process of capture, separation, and reduction of CO2 to CO is an energy and cost intensive process.

[0010] FIG. 1 depicts a schematic view of a conventional system 100 for capture, concentration, and reduction of carbon dioxide (CO2) in accordance with some embodiments of the present disclosure. The system 100 includes a section 102 for CO2 capture, a section 104 for CO2 concentration, and a section 106 for CO2 reduction. The system 100 begins at section 102 where ambient air or a flue gas 108 enters an air contractor 110. Within the air contractor 110, CO2 from the ambient air or a flue gas 108 is reacted to form a carbonate 112. For example, one exemplary reaction can be: 2NaOH + CO2 Na2COs + H2O. Another exemplary reaction can be: 2K0H + CO2 K2CO3 + H2O. The carbonate 112 next enters section 104 where a causticizer and clarificator 114 coverts the carbonate 112 into a second carbonate 116 using a hydroxide 118 provided by a slaker 120. For example, one exemplary reaction can be: Na2COs+ Ca(OH)2 CaCCh + 2NaOH. The second carbonate 116 enters a

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[0012] 2 calciner 122 and the resulting hydroxide 124 is recycled for use in the air contractor 110. In the calciner 122, the second carbonate is converted to CO2 126 in the presence of an oxygen (O2) atmosphere 127 provided by an air separation unit 128. For example, one exemplary reaction can be: CaCCh CO2 + CaO. The CO2 126 next enters section 106 and the resulting oxide 128 is recycled to the slaker 120. At section 106, the CO2 126 enters a reverse water gas shift (RWGS) reactor 130 which converts the CO2 126 to CO 132 using H2 134 provided by an electrolysis reactor 136. An alternative to the RWGS reactor is electrochemical reduction in an alkaline electrolyzer which uses CO2 as an input gas stream. Alkaline electrolyzers have a problem where CO2 forms carbonate which passes through an anion exchange membrane of the electrolyzer. The carbonate is either lost, leading to poor conversion of the CO2, or further regeneration of the carbonate is needed to recover the CO2. The CO 132 can be utilized to prepare fuels and other chemical products.

[0013] The system 100 requires numerous process steps to ultimately produce CO. In some instances, the system 100 uses low efficiency and / or energy intensive processes. For example, the air contactor 110 is large and energy intensive to remove a sufficient amount of CO2 from the ambient air or a flue gas. In another example, calcination is a high temperature process which requires high energy to convert the second carbonate to carbon dioxide. In yet another example, electrolysis is needed to produce hydrogen (H2), which is inefficiently used to convert carbon dioxide to carbon monoxide in the thermal process of RWGS.

[0014] Accordingly, there is a need in the art for more efficient and / or lower energy intensive systems for capturing carbon dioxide and converting the captured carbon dioxide to carbon monoxide for using as fuels or in the manufacture of other chemicals.

[0015] Brief Summary of Disclosure

[0016] The present disclosure is related to methods and systems for reduction of carbon dioxide (CO2).

[0017] In some embodiments of the present disclosure, a system comprises a preconcentrator for receiving ambient air or flue gas and converting the same into a gas stream comprising carbon dioxide (CO2) in a concentration greater than about 25 percent by volume (vol.%); an air contactor for receiving the gas stream, removing at least a portion of CO2 from the gas stream, and converting the removed CO2 into a solution comprising a carbonate having a molar ratio of carbon to alkali metal of 0.5 to 1.0; and a carbonate electrolyzer for receiving and converting the carbonate to carbon monoxide (CO) or methanol (CH3OH), where the carbonate electrolyzer comprises a single bipolar membrane.

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[0019] 3

[0020] In some embodiments of the present disclosure, a method of producing carbon monoxide (CO) or methanol (CH3OH), comprising absorbing carbon dioxide (CO2) from ambient air or flue gas using sorbent disposed in a moving bed absorber; desorbing the CO2 from the saturated sorbent to form a gas stream comprising carbon dioxide (CO2) in a concentration greater than 25 vol.%; removing CO2 from the gas stream, and converting the removed CO2 into a solution comprising a carbonate having a molar ratio of carbon to alkali metal of 0.5 to 1, wherein the remaining gas stream comprises xenon (Xe) and has a reduced concentration of CO2 in comparison to the gas stream; and reacting the carbonate to form carbon monoxide (CO) or methanol (CH3OH).

[0021] In some embodiments of the present disclosure a system comprises a preconcentrator for receiving ambient air or flue gas and converting the same into a gas stream comprising carbon dioxide (CO2) in a concentration greater than about 25 percent by volume (vol.%); an air contactor for receiving the gas stream and converting the same into a carbonate; a first apparatus for converting the carbonate to CO2; and a second apparatus for reducing the CO2 to CO, wherein the first apparatus comprises a causticizer and clarificatory, a slaker, a calciner, and an air separator unit, and wherein the second apparatus comprises a reverse water gas shift (RWGS) reactor and an electrolysis reactor.

[0022] In some embodiments of the present disclosure a system comprises an air contactor for receiving a gas stream comprising CO2 and converting the same into a carbonate having a C / K ratio of 0.5 or less, where the C / K ratio is non-zero; and a carbonate electrolyzer for receiving the carbonate having the C / K ratio of 0.5 or less, where the C / K ratio is non-zero, and converting the same to CO or methanol, wherein the carbonate electrolyzer comprise two bipolar membranes and a cation exchange membrane therebetween.

[0023] Brief Summary of Drawings

[0024] To assist in understanding the present disclosure, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:

[0025] Figure 1 depicts a schematic view of a conventional system for capture, concentration, and reduction of carbon dioxide (CO2) in accordance with some embodiments of the present disclosure.

[0026] Figure 2 depicts a system for capture, concentration, and reduction of CO2 in accordance with some embodiments of the present disclosure.

[0027] Figure 3 A depicts a partial schematic view of the system of Fig. 2 in accordance with some embodiments of the present disclosure.

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[0029] 4

[0030] Figures 3B to 3D depict schematic views of a preconcentrator in accordance with some embodiments of the present disclosure.

[0031] Figure 3E depicts a schematic view of a xenon recovery system in accordance with some embodiments of the present disclosure.

[0032] Figure 4 depicts a system for capture, concentration, and reduction of CO2 and Xe in accordance with some embodiments of the present disclosure.

[0033] Figure 5 depicts an exploded schematic view of an electrolyzer of the system of Fig. 4 in accordance with some embodiments of the present disclosure. Figure 6 depicts a system for capture and reduction of CO2 and Xe in accordance with some embodiments of the present disclosure.

[0034] Figure 7 depicts a schematic view of an electrolyzer of the system of Fig. 6 in accordance with some embodiments of the present disclosure.

[0035] Detailed Description

[0036] Methods and systems for the capture, concentration, and / or reduction of carbon dioxide (CO2) and xenon (Xe) are disclosed herein. These and other aspects of the disclosed subject matter are discussed in more detail below.

[0037] It should be understood at the outset that, although example implementations of embodiments of the disclosure are illustrated below, the present disclosure can be implemented using any number of techniques, whether currently known or not. The present disclosure should in no way be limited to the example implementations, drawings, and techniques illustrated below. Additionally, the drawings are not necessarily drawn to scale.

[0038] The terms used in this specification generally have their ordinary meanings in the art, within the context of this disclosure and in the specific context where each term is used. Certain terms are discussed below, or elsewhere in the specification, to provide additional guidance to the practitioner in describing the methods of the disclosure and how to use them.

[0039] As used herein, the use of the word “a” or “an” when used in conjunction with the term “comprising” in the claims and / or the specification can mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.”

[0040] Still further, the terms “having,” “including,” “containing” and “comprising” are interchangeable and one of skill in the art is cognizant that these terms are open ended terms.

[0041] The term “about” or “approximately” means within an acceptable error range for the particular value as determined by one of ordinary skill in the art, which will depend in part on how the value is measured or determined, i.e., the limitations of the measurement system. For

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[0043] 5 example, “about” can mean within three or more than three standard deviations, per the practice in the art. Alternatively, “about” can mean a range of up to 20%, preferably up to 10%, more preferably up to 5%, and more preferably still up to 1% of a given value. Alternatively, particularly with respect to processes, the term can mean within an order of magnitude, preferably within five-fold, and more preferably within two-fold, of a value.

[0044] The use of terms ‘overlying’, ‘underlying’, ‘disposed on’ and similar referents in the context of the present disclosure are to be construed to cover both being separated and in direct contact with an adjacent structure. For example, a first layer ‘overlying’ or ‘disposed on’ a second layer means the first layer is above the second layer, where the first layer can be separated from the second layer by one or more intervening layers or the first layer can be in direct contact with the second layer. The terms ‘overlying’, ‘underlying’, ‘disposed’ are not intended to be construed to exclusively mean ‘in direct contact with’ an adjacent structure.

[0045] Embodiments of the systems disclosed herein can have one or more of the following: (1) preconcentrator that concentrates the ambient air or a flue gas into a gas stream having a higher concentration (percentage by volume) of CO2 and / or xenon (Xe), where a portion of the gas stream have CO2 can be utilized for direct carbonate electrolysis to form, for example carbon monoxide (CO) or methanol (CH3OH), and wherein a portion of the gas stream having Xe can be recovered to produce Xe gas of high purity; (2) an electrodialysis system that concentrates carbonate and reduces CO2 in a single process step via direct carbonate electrolysis; and (3) Xenon recovery system for recovering Xe gas from a remaining gas stream from which CO2 has been depleted.

[0046] Figure 2 depicts a system 200 for capture, concentration, and reduction of CO2 in accordance with some embodiments of the present disclosure. The same numbering as system 100 is used where applicable. At section 102, a preconcentration 202 converts ambient air or a flue gas 108 into gas stream 204 having a higher concentration of CO2 and Xe than in the ambient air or flue gas 108. For example, the gas stream 204 can range in CO2 concentration from about 10 percent by volume (vol.% to about 75 vol.%. In some embodiments, the CO2 concentration can be greater than about 25%. In some embodiments, the CO2 concentration can be about 25% to about 75%. The gas stream 204 can have a Xe concentration range from about 10 parts per million (ppm) to about 1000 ppm. In terms of vol.%, about 100 ppm of Xe is equivalent to about 10'4vol fraction, or about 0.01 vol.%. The vol.% of Xe in the gas stream 204 can be about 1000 times higher than in the ambient air or flue gas 108. In some embodiments, the gas stream 204 can include about 50 vol.% CO2 and about 50 vol.% of other

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[0048] 6 gases, including Xe and water. Gas stream 204 can flow to an air contactor 206. The air contactor 206 can be smaller than the air contactor 110 of system 100 because the incoming gas stream 204 is much higher in CO2 concentration than ambient air or a flue gas 108. The air contactor 206 can be lOOOx smaller and could use a lower cost configuration due to the smaller volume handling requirements. One example includes using a bubble cap tray contactor which has good gas liquid contact where liquid load is small compared to gas flow rate. Typically, a bubble cap tray is not usable in conventional DAC due to a higher associated pressure drop, which would significantly increase energy requirements when moving large quantities of ambient air or a lower concentration flue gas.

[0049] The air contactor 206 can capture CO2 from the gas stream 204 and convert the CO2 into a carbonate 112 for further processing downstream. Further, a remaining gas stream 208, which is depleted of CO2, can be further processed to recover Xe in a Xe recovery system 210 as described herein. The air concentrator 206 can comprises a carbonate scrubber which can contain a solution that can chemically react with CO2 in the gas stream 204 to convert the CO2 into the carbonate 112, which can be in a liquid form. The solution can include an alkali metal hydroxide. For example, the alkali metal can include potassium (K) or sodium (Na). In some embodiments, the solution can include potassium hydroxide and / or sodium hydroxide. In some embodiments, the solution is a potassium hydroxide (KOH) solution. The air contactor 206 can be similar to a conventional air contactor, except that that the air contactor 206 is processing a gas stream (i.e., the gas stream 204) which has high CO2 concentration. The air contactor 206 can be smaller than a conventional air contactor which is used to process a gas stream with a dilute concentration of CO2. Further, the air contactor 206 can consume less power than a conventional air contactor which can have a high pressure drop. In contrast, the air contactor 206 does not have as large of a volume of gas stream to push as a conventional air contactor.

[0050] Figure 3A depicts a partial schematic view of the preconcentrator 202 in accordance with some embodiments of the present disclosure. The preconcentrator 202 includes a direct air capture system 302 which can include a carbon sorbent 304. Details of the carbon sorbent can be found in EP2717986A1, which is incorporated by reference herein. For example, the carbons sorbent 304 can be a carbon bead with a high pore volume. The carbon sorbent 304 can be made, for example, by heat treating polyvinylidene chloride (PVDC) to form carbon beads. The heat treating process can include pyrolysis of the PVDC at a temperature below the melting point of the PVDC, and can further not use a binder. The carbon beads can be spherical or approximately spherical and can have diameters ranging from about 200 microns to 800

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[0052] 7 microns. Absence of binders in the heat treatment process can result in an increased surface area for absorption. The pore size distribution of the carbon beads can be about 0.5 nm to about 0.8 nm. The carbon beads can be selective to CO2 and / or Xe and at least partially reject nitrogen (N2) and oxygen (O2) gases. The carbon beads can have an attrition resistance of < 0.01% weight loss per hour (based on ASTM D5757). The carbon beads can have a yield stress of > 20,000 pounds per square inch (psi). The carbon beads can have a density from about 0.75 g / cm3to about 1.50 g / cm3, for example, about 1.12 g / cm3. These exemplary properties of the carbon beads can allow the beads to withstand mechanical stresses of the systems herein, such as the transportation system 316 discussed below, without substantial degradation of the beads over numerous cycles. However, other sorbents which are capable of absorbing CO2 and / or Xe can be utilized in the systems and methods of the present disclosure. In the system 302, the ambient air or a flue gas 108 enters the system 302 and passes through the sorbent 304 where CO2 and / or Xe is depleted from the ambient air or a flue gas 108 by the sorbent 304. The depleted ambient air or a flue gas 306 exits the system 302. The sorbent 304, now having CO2 and / or Xe adsorbed thereto, enters into a regenerator 308 where, under reduced pressure conditions from vacuum pump 310 (and optionally, or alternatively, with steam assisted flow — not shown), CO2 and / or Xe desorbs from the sorbent 304 and collects in a separator 312 (along with water). The regenerated sorbent 309 (i.e., cleaned of adsorbed CO2 and / or Xe) is returned to the system 302 from the regenerator 308. In the separator 312, the water and CO2 and / or Xe are separated, where the gas stream 204 flows to the air concentrator 206 and the water 314 is retrieved for other uses. For example, the water 314 could be flowed to the electrolysis reactor 136 for conversion to H2 134.

[0053] Figure 3B depicts a schematic view of the preconcentrator 202 in accordance with some embodiments of the present disclosure. The preconcentrator 202 includes the system 302, the regenerator 308, and a sorbent transportation system 316 for transporting the sorbent 304 with CO2 and / or Xe absorbed to the regenerator 308 and for transporting the regenerated sorbent 309 to the system 302 for re-use.

[0054] The system 302 can include a vertical moving bed absorber 318 for holding the sorbent 304. The absorber 318 includes an inlet 320 for receiving the ambient air or flue gas 108 and an outlet 322 for exhausting the depleted ambient air or flue gas 306 after passing through the sorbent 304. The sorbent 304 can be disposed in the absorber 318 in the form of a packed structure. The sorbent 304 can be moving from an upper portion of the absorber 318 proximate the outlet 322 towards a lower portion proximate the inlet 320. While the sorbent 304 is in

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[0056] 8 motion, the flow of ambient air or flue gas 108 can be in the opposite direct to the motion of the sorbent 304, i.e., from the lower portion of the absorber 318 proximate the inlet 108 towards the upper portion of the absorber proximate the outlet 322. While in motion, the sorbent 304 can be capturing CO2 and / or Xe from the ambient air and / or flue gas 108. In some embodiments, the sorbent 304 can selectively capture CO2 and / or Xe and reject N2 and O2, which can be exhausted in depleted ambient air or flue gas 306.

[0057] The sorbent 304 can be kept in motion by the sorbent transportation system 316 which can remove sorbent 304 with CO2 and / or Xe absorbed at the lower portion of the absorber 318 and which can supply regenerated sorbet 309 at the upper portion of the absorber 318. The sorbent transportation system 316 can include a first stage 324 for transporting saturated sorbent 304 to the regenerator 308. The sorbent transportation system 316 can include a second stage 326 for transporting the regenerated sorbent 309 to the vertical moving bed absorber 318. The first and second stage 324, 326 can, independently, be a bucket elevator, a pneumatic lift, or another suitable transportation system for moving the sorbent between the system 302 and the regenerator 308. In some embodiments, and depicted in FIGS. 3C and 3D, the transportation system 316 can be a bucket elevator. For example, at an entry point (depicted in FIG. 3C) to the first or second stage 324, 326 a saturated sorbent 304 or a regenerated sorbent 309 enters one of a plurality of buckets 328, where the buckets 328 are attached to a circulating system 330 that provides empty buckets to fill and transports filled buckets away to an exit point, where the filled buckets 328 are unloaded. As depicted in FIG. 3D, at the exit point of the first or second stage 324, 326, the filled bucket 328 drops the saturated sorbent 304 into the regenerator 308 or drops the regenerated sorbent 309 into the absorber 318. Though depicted in FIGS. 3C and 3D as each bucket 328 filled with one sorbent 304 or 309, each bucket 328 can carry more than one sorbent 304 or 309 in some embodiments.

[0058] The regenerator 308 can include a first hopper 332, a regeneration chamber 334, and a second hopper 336. The saturated sorbent 304 can exit the first stage 324 into the first hopper 332. The first hopper 332 can hold a plurality of the saturated sorbent 304. The first hopper 332 (and the second hopper 336) can act as an interface between the absorber 318 and the regeneration chamber 334 to meter the movement of the saturated sorbent 304 and regenerated sorbent 309 therebetween. The saturated sorbent 304 can be gravity fed from the first hopper 332 into the regeneration chamber 334. The regeneration chamber 334 can have a smaller volume than the absorber 318. The smaller volume of the regeneration chamber 334 can reduce energy costs by having a smaller volume on which to pull a vacuum. The regeneration chamber

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[0060] 9

[0061] 334 can use a vacuum pressure swing absorption to desorb the absorbed CO2 and / or Xe, and other absorbents such as water using the vacuum pump 310. The vacuum pump 310 is representative, and can include one or more vacuum pumps, such as a roughing pump and a lower pressure pump, such as a turbo pump or other pump for evacuating the regenerator chamber 334 to lower pressures. For example, vacuum pressure in the regeneration chamber 334 can range from about 10 torr to below about 1 torr. For example, between about 760 torr and about 10 torr, components of the gas such as N2 and / or O2 can be desorbed. For example, below about 10 torr components such as CO2 and / or Xe can be desorbed. Alternatively, or in combination with vacuum pressure swing absorption, a thermal process can be utilized to desorb gas molecules from the sorbent 304. For example, a thermal process can include using steam to desorb gas molecules from the sorbent 304. The desorbed gases can enter the separator 312 to remove water 314 and form the gas stream 204. The regenerated sorbent 309 can exit the regeneration chamber 334 into the second hopper 336. From the second hopper 336, the regenerated sorbent 309 can enter the second transportation stage 326 and be returned to the absorber 318 for re-use.

[0062] Further, a gas 311, which is initially desorbed, from the saturated sorbent 304 as the pressure in the regeneration chamber 334 is lowered (e.g., from 760 torr to below 10 torr), can be recycled based to the absorber 318 to recover additional amounts of CO2 and / or Xe. For example, the gas 311 can contain primarily components, such as N2 and / or O2, and secondarily can contain amounts of CO2 and / or Xe. Additional, CO2 and / or Xe can be captured from the gas 311 upon recycling to the absorber 318.

[0063] Returning to the air contactor 206, the remaining gas stream 208, which is depleted of CO2, can be further processed to recover Xe in a Xe recovery system 210. An exemplary Xe recovery system 210 is depicted in FIG. 3E in accordance with some embodiments of the present disclosure. The Xe recovery system 210 includes a fixed bed absorber 338, the fixed bed absorber having a sorbent 340. The sorbent 340 can be the same as the sorbent 304, or another sorbent that is capable of absorbing Xe. The fixed bed absorber 338 can be coupled to a vacuum pump 342 (one more vacuum pumps can be used - not depicted in FIG. 3E). In operation, the remaining gas stream 208 enters the fixed bed absorber 338, where Xe can be absorbed by the sorbent 340 and a remaining gas stream 344, depleted of Xe, can be exhausted from the fixed bed absorber 338. The fixed bed absorber 338 can be brought to a lower pressure using the vacuum pump 342 to desorb the Xe gas and form a second gas stream 346 comprising Xe. The second gas stream 346 can further include CO2 and / or water than can require further

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[0065] 10 processing for removal. For example, CO2 and / or water can be present in the second gas stream 346 in trace amounts, such as ranging from about 0.1 vol.% to about 10 vol.%. The system 210 can further include a second fixed bed absorber 348 having a sorbent 350. The sorbent 350 can be the same or different than the sorbent 340. In some embodiments, the sorbent 350 can be alumina. In operation, the second gas stream 346 enters the second fixed bed absorber 348, wherein CO2 and / or water can be absorbed by the sorbent 350 as the second gas stream 346 passes through the sorbent 350 to form a third gas stream 347. The third gas stream 347 comprising Xe, at a higher concentration than the second gas stream, and depleted of CO2 and / or water. The second fixed bed absorber 348 can be coupled to a vacuum pump 352, wherein the vacuum pump can be utilized to desorb CO2 and / or water from the sorbent 350. The third gas stream 347, depleted of CO2 and / or water, exits the second bed absorber 348 and enters a cryogenic apparatus 354. The cryogenic apparatus 354 freezes the third gas stream 347. Xe gas 356, which has a different sublimation temperature than remaining gases in the third gas stream 347, such as N2, O2, argon (Ar), CO2, and / or water vapor (H2O), can be selectively sublimed from the frozen third gas stream 347 and recovered. The Xe gas 356 can be high purity, greater than about 99.000%, and in some embodiments, as high as about 99.999% pure.

[0066] Figure 4 depicts a system 400 for capture, concentration, and reduction of CO2 in accordance with some embodiments of the present disclosure. The system 400 includes the preconcentrator 202 and air contactor 206 as discussed previously. However, instead of sections for concentration and reduction of CO2 (i.e., sections 104 and 106 in FIGS. 1-3), the system 400 includes a carbonate electrolyzer 402, which is used to directly convert the carbonate 112 into CO 132 through bipolar membrane electrolysis.

[0067] Figure 5 depicts an exploded schematic view of the carbonate electrolyzer 402 of the system 400 in accordance with some embodiments of the present disclosure. The carbonate electrolyzer 402 is an electrochemical device where a potential difference is applied between an anode 404 and a cathode 406 to facilitate electrochemical reactions. The electrolyzer 402 includes a bipolar membrane 408 between the anode 404 and the cathode 406. As shown in Fig. 5, the bipolar membrane is arranged such that water is separated by the membrane 408 where H+ions are directed towards the cathode 406 and OH' ions are directed toward the anode 404. At the site of the cathode 406, the anion (e.g., HCO3 ) from the carbonate 112 (e.g., KHCO3) reacts with H+ ions provided by the membrane 408 to form H2O and CO2, which is immediately reduced by the cathode. The CO2 is reduced to CO by the electrochemical

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[0069] 11 reduction of CO2 (CO2RR): CO + 2OH'. The net reaction at the cathode is: CO + 2OH'. The presence of H+ provided by the bipolar membrane is used to drive the equilibrium reactions: KHCO3 + H+— HHC03 + K+and HHCO3 — > H2O + CO2. HHCO3 can be written equivalently as JfcCOs.The hydroxide 124 can be recycled back to the air contactor 206 for use therein.

[0070] The cathode 406 can include a catalyst layer 410 and current collector 412, where the catalyst layer 410 faces the membrane 408. The cathode 406 can be mounted on a flow plate 409, where the flow plate 409 can be used, for example, to contact the carbonate 112 with the cathode 406. The current collector 410 can be a carbon paper. The catalyst layer 410 can include a nickel-based single atom catalyst (Ni-SAC). A detailed description of the Ni-SAC can be found in the article titled “Integrated carbon capture and CO production from bicarbonates through bipolar membrane electrolysis” by Hakhyeon Song et al., Energy Environ. Sci., 2024, 17, 3570, published by the Royal Society of Chemistry, London, UK. However, other catalyst materials can also be utilized that have different selectivity and efficiency, and could produce varying reduced products, such as methanol, ethylene, or syngas as discussed herein.

[0071] The anode 404 can include an anode active material layer and a current collector (not depicted in FIG. 5). The anode 404 can be mounted on a flow plate 411, where the flow plate 411 can be used, for example, to contact water with the anode 404 and the bipolar membrane 408. At the anode 404, OH' ions provided by the membrane 408 can evolve oxygen (O2) in an oxygen evolution reaction, such as 4OH' O2 +H2O + 4e'. KOH electrolyte remains balanced and could be recirculated in the anode as the bipolar membrane provides the right quantity of OH' for the oxygen evolution reaction. Moreover, though depicted in FIG. 5 as entering at the anode, water is provided to the electrolyzer 402 as a solvent, for example, whereby cations and anions move through the solvent between the anode 404 and the cathode 606.

[0072] The electrolyzer 402 can be designed to work with a carbonate 112 that has a C / K ratio of 1, e.g., KHCO3, where the molar ratio of C / K is 1. However, as discussed below, the electrolyzer 402 can work with a carbonate that has a C / K ratio of less than 1 in some embodiments. An aqueous potassium / CCh system can include a number of species in solution, for example, KOH, K2CO3, KHCO3, and H2CO3, which respectively have C / K ratios of 0, 0.5, 1, and infinite. A C / K ratio is a molar ratio of carbon (C) to potassium (K) in the carbonate. More generally, the carbonate can have a molar ratio of carbon (C) to an alkali metal, such as potassium (K) or sodium (Na). Thus, in more general terms, the carbonate can have a C / A

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[0074] 12 ratio, which is the ratio of carbon (C) to alkali metal (A) in the carbonate. The electrolyzer 402 can be designed to work with a carbonate having a C / A ratio of 1. However, carbonate with C / A ratios of less than 1 can still be used in the electrolyzer 402 in some embodiments.

[0075] In the embodiments of the system 400, the preconcentrator 202 provides the gas stream 204 to the air concentrator 206. As a result of the gas stream 204 being high in CO2 concentration, the resulting carbonate 112 has a C / K ratio of 1 (e.g., KHCO3). Thus, the carbonate 112 is suitable for use in the electrolzyer 402. Alternatively, in the absence of the preconcentrator 202, the resulting carbonate 112 would have a C / K ratio less than 1 due to the lower concentration of CO2 entering the air contactor 206 from the ambient air or a flue gas 108. The electrolyzer 402 can still be used in the absence of the preconcentrator 202, but one or more intermediate concentration steps would need to be introduced between the air contactor and the electrolyzer obtain a carbonate having the desired C / K ratio of 1. Alternatively, the electrolyzer 402 can be used in absence of the preconcentrator 202 and without intermediate concentration steps between the air contactor 206 by using a flue gas stream with sufficiently high CO2 concentration that a carbonate having a C / K ratio of 1 result from the air contactor 206.

[0076] Fig. 5 depicts an exemplary embodiment, where the electrolyzer 402 is utilized to produce carbon monoxide (CO). For example, to selectively produce CO, the cathode material can include nickel-based catalysts, such as one or more of nitrogen-doped carbon-supported single-atom nickel (Nix-Ny-Cz), nickel -nitrogen coordination complexes (Ni-Nx, where x is an integer from 2 to 4), nickel phthalocyanine (NiPc), nickel cyclam, nickel tetraphenylporphyrin (Ni-TPP), metallic nickel nanoparticles that are surface-modified to suppress hydrogen evolution, and single nickel atom catalysts (Ni-SAC), for example, such as Ni-SAC disclosed in Song et al., Integrated carbon capture and CO production from bicarbonates through bipolar membrane electrolysis, Energy Environ. Sci., 2024, 17, 3570, published by the Royal Society of Chemistry, London, UK, which is incorporated by reference herein. Alternatively, the electrolyzer 402 can be utilized to produce methanol (CH3OH) (not shown in Fig. 5). For example, to selectively produce methanol, the cathode material can include copper-based catalysts, molybdenum-based catalysts, indium-based catalysts, palladium-based catalysts, gallium-based catalysts, and / or cobalt-based catalysts. Exemplary copper-based catalysts can include one or more of metallic copper (Cu), cuprous oxide (CU2O), cupric oxide (CuO), oxide-derived copper, copper-zinc alloys (CuZn), and copper-silver alloys (CuAg). Exemplary molybdenum-based catalysts can include molybdenum disulfide (M0S2),

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[0078] 13 molybdenum carbide (M02C), molybdenum phosphide (MoP), molybdenum oxides (MoOs), or transition metal dichalcogenides (TMDs) comprising molybdenum. Exemplary indium- based catalysts can include indium oxide (I Ch). Exemplary palladium-based catalysts can include one or more of metallic palladium (Pd) and palladium zinc alloys (PdZn). Exemplary gallium-based catalysts can include one or more of nickel gallium alloys (NiGa) and palladium gallium alloys (PdGa). Exemplary cobalt-based catalysts can include one or more of cobalt protoporphyrins, cobalt and pthalocyanine(CoPc). At the site of the cathode 406, the carbonate 112 (e.g., K2CO3) reacts with H+ ions provided by the membrane 408 to form CO2, (e.g., 2K2CO3 +4H ->2CO2+4I< ) which is immediately reduced by the cathode. The CO2 is reduced to CH3OH by the electrochemical reduction of CO2 (CO2RR): 2 CH3OH + 4OET. At the anode 404, the following reaction can take place: 12OH- -^3O2+6H2O+ 12e . The net reaction can be: 6H2O + 2K2CO3 3O2+ 2CH3OH + 4K0H. The hydroxide 124 can be recycled back to the air contactor 206 for use therein. It is noted that a carbonate used in the electrolyzer 402 to form methanol can be one with a C / K ratio of less than 1, such as K2CO3. K2CO3 can be in an equilibrium with KHCO3, i.e., a carbonate with a C / K ratio of 1. For example, the equilibrium can be: K2CO3 + H+->KHCC>3 + K+, KHCO3 H2CO3 + K+, H2CO3 ->H2O + CO2. The net reaction can be: K2CO3 + 2H+->2I< +H2O + CO2.

[0079] Figure 6 depicts a system 600 for capture and reduction of CO2 in accordance with some embodiments of the present disclosure. The system 600 includes the air contactor 110 and a carbonate electrolyzer 602. In operation, the ambient air or a flue gas 108 enters the air contactor 110 and is processed to form the carbonate 112. The carbonate 112 has a C / K ratio of less than 1, for example, 0.5. An exemplary carbonate 112 can be K2CO3 or other carbonates with C / K ratio of less than 1. The carbonate 112 enters the carbonate electrolyzer 602 and is converted to carbon monoxide 132 (or methanol (not shown in FIG.6) using the appropriate catalysts as discussed herein). Hydroxide 124, resulting from the conversion process is recycled for use in the air concentrator 110. The carbonate electrolyzer 602 differs from that of electrolyzer 402 in that electrolyzer system 602 is capable of using a carbonate 112 having a C / K ratio of less than 1, such as 0.5, by leveraging in-situ electrodialysis. In some embodiments, the C / K ratio can be less than 1, where the C / K ratio is non-zero. In some embodiments, the C / K ratio can be 0.5 or less, where the C / K ratio is non-zero.

[0080] Figure 7 depicts a schematic view of the electrolyzer system 602 in accordance with some embodiments of the present disclosure. The electrolyzer system 602 includes the anode

[0081] ACTIVE 127425450.3 081546.0486

[0082] 14

[0083] 404, the cathode 406, and the bipolar membrane 408, and additionally a second bipolar membrane 604 between the membrane 408 and the anode 404, and a cation exchange membrane 606 disposed between the bipolar membrane 604 and the bipolar membrane 408. The second bipolar membrane 604 functions in the same manner as the membrane 400, i.e., the membrane 606 separates water into H+ions and OH' ions, where the H+ions flow towards the cation exchange membrane 606 and the OH' ions flow towards the anode 404. In operation, the carbonate 112 enters the electrolyzer system 602 in a space 603 between the second bipolar membrane 604 and the cation exchange membrane 606. The second carbonate 112, e.g., K2CO3, reacts with H+ions provided by the second bipolar membrane 604 to form a carbonate 608 having C / K ratio of 1, e.g., KHCO3. The carbonate 608 exits the space 603 between the membranes 604, 606, bypasses a space 605 between the membrane 606 and the bipolar membrane 408, and enters the cathode 406 such that the cathode 406 is between the carbonate 608 and the bipolar membrane 408 upon entrance of the carbonate 608.

[0084] At the cathode 406, the anion (e.g., HCO3 ) from the carbonate 608 (e.g., KHCO3) reacts with H+ions provided by the membrane 408 to form CO2 and H2O. The CO2 is reduced to CO 132 and a hydroxide 610 by the electrochemical reduction of CO2 (CO2RR): CO2 + H2O + 2e' CO + 2OH'. The net reaction at the cathode is: H2CO3 + 2 e- CO + 2OH'. The presence of H+ provided by the bipolar membrane is used to drive the equilibrium reactions: KHCO3 + H+<-> HHCO3 + K+and HHCO3 <-> H2O + CO2. As discussed above, HHCO3 and H2CO3 are equivalent notations.

[0085] The hydroxide 610 bypasses the bipolar membrane 408 and enters the space 605 between the cation exchange membrane 606 and bipolar membrane 408. Further, additional hydroxide 610 is formed in the space 605 from cations (e.g., K+ions) that flow through the cation exchange membrane 606 from the space 603 and from OH' ions that are provided by the membrane 408. The hydroxide 610 can be recycled for use in the air contactor 110.

[0086] At the anode 404, OH' ions provided by the membrane 408 can evolve oxygen (02) in an oxygen evolution reaction, such as 4OH' O2 +H2O + 4e'.

[0087] In some embodiments of the present disclosure, a system comprises a preconcentrator for receiving ambient air or flue gas and converting the same into a gas stream comprising carbon dioxide (CO2) in a concentration greater than about 25 percent by volume (vol.%); an air contactor for receiving the gas stream, removing at least a portion of CO2 from the gas stream, and converting the removed CO2 into a solution comprising a carbonate having a molar ratio of carbon to alkali metal of 0.5 to 1.0; and a carbonate electrolyzer for receiving and

[0088] ACTIVE 127425450.3 081546.0486

[0089] 15 converting the carbonate to carbon monoxide (CO) or methanol (CH3OH), where the carbonate electrolyzer comprises a single bipolar membrane.

[0090] The system of the preceding paragraph, where the preconcentrator further comprises a vertical moving-bed absorber having an interior volume for holding sorbent therein; a regeneration system for removing absorbed gas from saturated sorbent; and a sorbent transport system for transporting the saturated sorbent to the regeneration chamber and returning regenerated sorbent to the vertical moving-bed absorber.

[0091] The system of any of the two preceding paragraphs, wherein the sorbent transport system further comprises a first stage for transporting the saturated sorbent to the regeneration system; and a second stage for transporting the regenerated sorbent to vertical moving-bed absorber.

[0092] The system of any of the three preceding paragraphs, wherein the regeneration system further comprises a first hopper for receiving the saturated sorbent from the first stage of the sorbent transport system; a regeneration chamber for receiving the saturated sorbent from the first hopper and regenerating the saturated sorbent into regenerated sorbent by removing absorbed gas from the saturated sorbent; and a second hopper for receiving the regenerated sorbent from the regeneration chamber, wherein the second stage of the sorbent transport system receives the regenerated sorbent from the second hopper and returns the regenerated sorbent to the vertical moving-bed absorber.

[0093] The system of any of the four preceding paragraphs, wherein the air contactor further comprises a vacuum pump coupled to the regeneration chamber and for reducing pressure in the regeneration chamber to cause desorption of the absorbed gas from the saturated sorbent.

[0094] The system of any of the five preceding paragraphs, wherein the preconcentrator further comprises a separator for receiving the absorbed gas from the regeneration chamber and separating the absorbed gas from water to form the gas stream.

[0095] The system of any of the six preceding paragraphs, where the carbonate electrolyzer further comprises an anode; and a cathode, wherein the single bipolar membrane is disposed between the anode and the cathode.

[0096] The system of any of the seven preceding paragraphs, wherein the cathode comprises a cathode active material, and wherein the cathode active material comprises copper (Cu), nickel (Ni), and / or molybdenum (Mo).

[0097] ACTIVE 127425450.3 081546.0486

[0098] 16

[0099] The system of any of the eight preceding paragraphs, wherein the anode comprises an anode active material, and wherein the anode active material comprises nickel (Ni), iridium (Ir), ruthenium (Ru), cobalt (Co), and / or iron (Fe).

[0100] The system of any of the nine preceding paragraphs, wherein the single bipolar membrane dissociates water into protons (H+) and hydroxide (OH ), wherein the protons are directed to the cathode and the hydroxide is directed to the anode.

[0101] The system of any of the ten preceding paragraphs, wherein the cathode converts the carbonate to CO or methanol.

[0102] The system of any of the eleven preceding paragraphs, wherein oxygen (O2) and water (H2O) are formed at the anode.

[0103] The system of any of the twelve preceding paragraphs, where the air contactor further comprises a scrubber for converting the gas stream into the solution comprising the carbonate having a molar ratio of carbon to alkali metal of 0.5 to 1.0.

[0104] The system of any of the thirteen preceding paragraphs, wherein the alkali metal is potassium (K) or sodium (Na).

[0105] The system of any of the fourteen preceding paragraphs, wherein the gas stream further comprises xenon (Xe), and wherein the remaining gas stream, after CO2 remove at the air contactor, comprises Xe.

[0106] The system of any of the fifteen preceding paragraphs, further comprising a Xe recovery system, the Xe recover system comprising a fixed bed absorber having an interior volume for holding sorbent, wherein the sorbent absorbs Xe from the remaining gas stream to obtain a second gas stream comprising Xe, the second gas stream having a higher concentration of Xe than the remaining gas stream; and a second fixed bed absorber having an interior volume for holding sorbent, wherein the sorbent removes at least one of CO2 or water vapor (H2O) from the second gas stream.

[0107] The system of any of the sixteen preceding paragraphs, wherein the Xe recovery system further comprises a cryogenic apparatus for freezing the second gas stream and selective sublimation of gaseous Xe from the second gas stream.

[0108] In some embodiments of the present disclosure, a method of producing carbon monoxide (CO) or methanol (CH3OH), comprising absorbing carbon dioxide (CO2) from ambient air or flue gas using sorbent disposed in a moving bed absorber; desorbing the CO2 from the saturated sorbent to form a gas stream comprising carbon dioxide (CO2) in a concentration greater than about 25 vol.%; removing at least a portion of CO2 from the gas

[0109] ACTIVE 127425450.3 081546.0486

[0110] 17 stream, and converting the removed CO2 into a solution comprising a carbonate having a molar ratio of carbon to alkali metal of 0.5 to 1, wherein the remaining gas stream comprises xenon (Xe) and has a reduced concentration of CO2 in comparison to the gas stream; and reacting the carbonate to form carbon monoxide (CO) or methanol (CH3OH).

[0111] The method of the preceding paragraph, wherein absorbing CO2 further comprises flowing the ambient air or flue gas in a first direction; and moving the sorbent in a second direction, wherein the second direction is opposite to the first direction.

[0112] The method of any of the two preceding paragraphs, further comprising removing the saturated sorbent from the moving bed absorber using a first transport stage, where saturated sorbent is disposed in one or more first buckets configured to move along the first transport stage.

[0113] The method of any of the three preceding paragraphs, further comprising transferring the one or more saturated sorbent from the first transport stage into a first hopper; transferring the one or more saturated sorbent from the first hopper into a regeneration chamber; desorbing the CO2 from the one or more saturated sorbent to form the gas stream in the regeneration chamber and to regenerate the one or more sorbent; and transferring the one or more regenerated sorbent to a second hopper from the regeneration chamber.

[0114] The method of any of the four preceding paragraphs, further comprising transferring the one or more regenerated sorbent from second hopper using a second transport stage, where one or more regenerated sorbent are disposed in one or more second buckets configured to move along the second transport stage; and transferring the one or more regenerated sorbent from the second transport stage to the moving bed absorber.

[0115] The method of any of the five preceding paragraphs, wherein removing CO2 from the gas stream further comprises reacting the gas stream with a solution comprising an alkali metal hydroxide to form the carbonate and the remaining gas stream comprising Xe.

[0116] The method of any of the six preceding paragraphs, wherein the alkali metal of the alkali metal hydroxide is potassium (K) or sodium (Na).

[0117] The method of any of the seven preceding paragraphs, wherein reacting the carbonate to form carbon monoxide (CO) or methanol (CH3OH) further comprising reacting the carbonate with protons at a cathode to form CO or CH3OH, wherein the protons are formed by dissociating water (H2O) at a single bipolar membrane adjacent to the cathode; and reacting hydroxide ions at an anode to form oxygen (O2) and water (H2O), wherein the hydroxide ions are formed by dissociating water at the single bipolar membrane adjacent to the anode.

[0118] ACTIVE 127425450.3 081546.0486

[0119] 18

[0120] The method of any of the eight preceding paragraphs, absorbing Xe from the remaining gas stream using sorbent disposed in a fixed bed absorber; desorbing the Xe from the sorbent to form a second gas stream comprising Xe, the second gas stream having a higher concentration of Xe than the remaining gas stream; removing at least one of CO2 or water vapor (H2O) from the second gas stream using second sorbent disposed in a second fixed bed absorber.

[0121] The method of any of the nine preceding paragraphs, after the removal of at least one of CO2 or water vapor (H2O) from the second gas stream, further comprising freezing the second gas stream; and selectively sublimating Xe from the second gas stream.

[0122] In some embodiments of the present disclosure a system comprises a preconcentrator for receiving ambient air or flue gas and converting the same into a gas stream comprising carbon dioxide (CO2) in a concentration greater than about 25 percent by volume (vol.%); an air contactor for receiving the gas stream and converting the same into a carbonate; a first apparatus for converting the carbonate to CO2; and a second apparatus for reducing the CO2 to CO, wherein the first apparatus comprises a causticizer and clarificatory, a slaker, a calciner, and an air separator unit, and wherein the second apparatus comprises a reverse water gas shift (RWGS) reactor and an electrolysis reactor.

[0123] In some embodiments of the present disclosure a system comprises an air contactor for receiving a gas stream comprising CO2 and converting the same into a carbonate having a C / K ratio of 0.5 or less, where the C / K ratio is non-zero; and a carbonate electrolyzer for receiving the carbonate having the C / K ratio of 0.5 or less, where the C / K ratio is non-zero, and converting the same to CO or methanol, wherein the carbonate electrolyzer comprise two bipolar membranes and a cation exchange membrane therebetween.

[0124] The scope of this disclosure encompasses all changes, substitutions, variations, alterations, and modifications to the example embodiments described or illustrated herein that a person having ordinary skill in the art would comprehend. The scope of this disclosure is not limited to the example embodiments described or illustrated herein. Moreover, although this disclosure describes and illustrates respective embodiments herein as including particular components, elements, feature, functions, operations, or steps, any of these embodiments can include any combination or permutation of any of the components, elements, features, functions, operations, or steps described or illustrated anywhere herein that a person having ordinary skill in the art would comprehend. Furthermore, reference in the appended statements to an apparatus or system or a component of an apparatus or system being adapted to, arranged

[0125] ACTIVE 127425450.3 081546.0486

[0126] 19 to, capable of, configured to, enabled to, operable to, or operative to perform a particular function encompasses that apparatus, system, component, whether or not it or that particular function is activated, turned on, or unlocked, as long as that apparatus, system, or component is so adapted, arranged, capable, configured, enabled, operable, or operative. Additionally, although this disclosure describes or illustrates particular embodiments as providing particular advantages, particular embodiments can provide none, some, or all of these advantages.

[0127] ACTIVE 127425450.3

Claims

081546.048620IN THE CLAIMS1. A system, comprising: a preconcentrator for receiving ambient air or flue gas and converting the same into a gas stream comprising carbon dioxide (CO2) in a concentration greater than about 25 percent by volume (vol.%); an air contactor for receiving the gas stream, removing at least a portion of CO2 from the gas stream, and converting the removed CO2 into a solution comprising a carbonate having a molar ratio of carbon to alkali metal of 0.5 to 1.0; and a carbonate electrolyzer for receiving and converting the carbonate to carbon monoxide (CO) or methanol (CH3OH), where the carbonate electrolyzer comprises a single bipolar membrane.

2. The system of claim 1, where the preconcentrator further comprises: a vertical moving-bed absorber having an interior volume for holding sorbent therein; a regeneration system for removing absorbed gas from saturated sorbent; and a sorbent transport system for transporting the saturated sorbent to the regeneration chamber and returning regenerated sorbent to the vertical moving-bed absorber.

3. The system of claim 2, wherein the sorbent transport system further comprises: a first stage for transporting the saturated sorbent to the regeneration system; and a second stage for transporting the regenerated sorbent to vertical moving-bed absorber.

4. The system of claim 2, wherein the regeneration system further comprises: a first hopper for receiving the saturated sorbent from the first stage of the sorbent transport system; a regeneration chamber for receiving the saturated sorbent from the first hopper and regenerating the saturated sorbent into regenerated sorbent by removing absorbed gas from the saturated sorbent; and a second hopper for receiving the regenerated sorbent from the regeneration chamber, wherein the second stage of the sorbent transport system receives the regenerated sorbent from the second hopper and returns the regenerated sorbent to the vertical moving bed absorber.

5. The system of claim 4, wherein the air contactor further comprises: a vacuum pump coupled to the regeneration chamber and for reducing pressure in the regeneration chamber to cause desorption of the absorbed gas from the saturated sorbent.

6. The system of claim 4, wherein the preconcentrator further comprises:ACTIVE 127425450.3081546.048621 a separator for receiving the absorbed gas from the regeneration chamber and separating the absorbed gas from water to form the gas stream.

7. The system of claim 1, where the carbonate electrolyzer further comprises: an anode; and a cathode, wherein the single bipolar membrane is disposed between the anode and the cathode.

8. The system of claim 7, wherein the cathode comprises a cathode active material, and wherein the cathode active material comprises copper (Cu), nickel (Ni), and / or molybdenum (Mo).

9. The system of claim 7, wherein the anode comprises an anode active material, and wherein the anode active material comprises nickel (Ni), iridium (Ir), ruthenium (Ru), cobalt (Co), and / or iron (Fe).

10. The system of claim 7, wherein the single bipolar membrane dissociates water into protons (H+) and hydroxide (OH ), wherein the protons are directed to the cathode and the hydroxide is directed to the anode.

11. The system of claim 7, wherein the cathode converts the carbonate to CO or methanol.

12. The system of claim 7, wherein oxygen (O2) and water (H2O) are formed at the anode.

13. The system of claim 1, where the air contactor further comprises: a scrubber for converting the gas stream into the solution comprising the carbonate having a molar ratio of carbon to alkali metal of 0.5 to 1.0.

14. The system of claim 7, wherein the alkali metal is potassium (K) or sodium (Na).

15. The system of claim 1, wherein the gas stream further comprises xenon (Xe), and wherein the remaining gas stream, after CO2 remove at the air contactor, comprises Xe.

16. The system of claim 15, further comprising: a Xe recovery system, the Xe recover system comprising: a fixed bed absorber having an interior volume for holding sorbent, wherein the sorbent absorbs Xe from the remaining gas stream to obtain a second gas stream comprising Xe, the second gas stream having a higher concentration of Xe than the remaining gas stream; and a second fixed bed absorber having an interior volume for holding sorbent, wherein the sorbent removes at least one of CO2 or water vapor (H2O) from the second gas stream.

17. The system of claim 16, wherein the Xe recovery system further comprises:ACTIVE 127425450.3081546.048622 a cryogenic apparatus for freezing the second gas stream and selective sublimation of gaseous Xe from the second gas stream.

18. A method of producing carbon monoxide (CO) or methanol (CH3OH), comprising: absorbing carbon dioxide (CO2) from ambient air or flue gas using sorbent disposed in a moving bed absorber; desorbing the CO2 from the saturated sorbent to form a gas stream comprising carbon dioxide (CO2) in a concentration greater than about 25 vol.% removing at least a portion of CO2 from the gas stream, and converting the removed CO2 into a solution comprising a carbonate having a molar ratio of carbon to alkali metal greater than .25, wherein the remaining gas stream comprises xenon (Xe) and has a reduced concentration of CO2 in comparison to the gas stream; and reacting the carbonate to form carbon monoxide (CO) or methanol (CH3OH).

19. The method of claim 18, wherein absorbing CO2 further comprises: flowing the ambient air or flue gas in a first direction; and moving the sorbent in a second direction, wherein the second direction is opposite to the first direction.

20. The method of claim 19, further comprising: removing the saturated sorbent from the moving bed absorber using a first transport stage, where saturated sorbent is disposed in one or more first buckets configured to move along the first transport stage.

21. The method of claim 20, further comprising: transferring the one or more saturated sorbent from the first transport stage into a first hopper; transferring the one or more saturated sorbent from the first hopper into a regeneration chamber; desorbing the CO2 from the one or more saturated sorbent to form the gas stream in the regeneration chamber and to regenerate the one or more sorbent; and transferring the one or more regenerated sorbent to a second hopper from the regeneration chamber.

22. The method of claim 21, further comprising: transferring the one or more regenerated sorbent from second hopper using a second transport stage, where one or more regenerated sorbent are disposed in one or more second buckets configured to move along the second transport stage; andACTIVE 127425450.3081546.048623 transferring the one or more regenerated sorbent from the second transport stage to the moving bed absorber.

23. The method of claim 18, wherein removing CO2 from the gas stream further comprises: reacting the gas stream with a solution comprising an alkali metal hydroxide to form the carbonate and the remaining gas stream comprising Xe.

24. The method of claim 23, wherein the alkali metal of the alkali metal hydroxide is potassium (K) or sodium (Na).

25. The method of claim 18, wherein reacting the carbonate to form carbon monoxide (CO) or methanol (CH3OH) further comprising: reacting the carbonate with protons at a cathode to form CO or CH3OH, wherein the protons are formed by dissociating water (H2O) at a single bipolar membrane adjacent to the cathode; and reacting hydroxide ions at an anode to form oxygen (O2) and water (H2O), wherein the hydroxide ions are formed by dissociating water at the single bipolar membrane adjacent to the anode.

26. The method of claim 18, further comprising: absorbing Xe from the remaining gas stream using sorbent disposed in a fixed bed absorber; desorbing the Xe from the sorbent to form a second gas stream comprising Xe, the second gas stream having a higher concentration of Xe than the remaining gas stream; removing at least one of CO2 or water vapor (H2O) from the second gas stream using second sorbent disposed in a second fixed bed absorber.

28. The method of claim 27, after the removal of at least one of CO2 or water vapor (H2O) from the second gas stream, further comprising: freezing the second gas stream; and selectively sublimating Xe from the second gas stream.

29. A system, comprising: a preconcentrator for receiving ambient air or flue gas and converting the same into a gas stream comprising carbon dioxide (CO2) in a concentration greater than about 25 percent by volume (vol.%); an air contactor for receiving the gas stream and converting the same into a carbonate; a first apparatus for converting the carbonate to CO2; andACTIVE 127425450.3081546.048624 a second apparatus for reducing the CO2 to CO, wherein the first apparatus comprises a causticizer and clarificatory, a slaker, a calciner, and an air separator unit, and wherein the second apparatus comprises a reverse water gas shift (RWGS) reactor and an electrolysis reactor.

30. A system, comprising: an air contactor for receiving a gas stream comprising CO2 and converting the same into a carbonate having a C / K ratio of 0.5 or less, where the C / K ratio is non-zero; and a carbonate electrolyzer for receiving the carbonate having the C / K ratio of 0.5 or less, where the C / K ratio is non-zero, and converting the same to CO or methanol, wherein the carbonate electrolyzer comprise two bipolar membranes and a cation exchange membrane therebetween.ACTIVE 127425450.3

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