Systems and methods for direct air capture of water and CO2

Abstract

An apparatus comprising: (A) an atmospheric water extraction unit; and (B) a direct air capture unit positioned downstream of the atmospheric water extraction unit and in communication with the atmospheric water extraction unit, the apparatus being capable of reversibly operating in (i) an adsorption mode for adsorbing water and CO2 from an incoming airstream and (ii) a regeneration mode for releasing the adsorbed water and CO2, the atmospheric water extraction unit comprising a first desiccant bed comprising a sorbent that adsorbs water from the incoming airstream during the adsorption mode and releases the water during the regeneration mode, and the direct air capture unit comprising a first moisture-reactive CO2 sorbent bed comprising a sorbent that adsorbs CO2 from the airstream during the adsorption mode and releases CO2 upon contact with water vapor during the regeneration mode.

Description

[Background technology]

[0001] Government support acknowledged This invention was made with Government support under Contract No. DE-AC05-76RL01830 awarded by the U.S. Department of Energy. The Government has certain rights in the invention.

[0002] Priority claim This application claims the benefit of the earlier filing date of U.S. Patent Application No. 63 / 303,407, filed January 26, 2022, which is incorporated by reference in its entirety.

[0003] background Distributed greenhouse gas (GHG) capture is an important part of a diverse portfolio of technologies for mitigating GHG emissions. Most of the 5.2 gigatons (Gt) of CO2 emitted each year in the United States is released in relatively small amounts from distributed sources (e.g., from small point sources or a few transported sources). For such emissions, point-source capture may not be feasible. In those cases, distributed CO2 capture serves as a cross-cutting and complementary approach to achieving economy-wide net-zero emissions.

[0004] Industrial direct air capture systems (DAC) are available, such as the Climeworks porous sorbent system (Spiteri et al., US Patent Application No. 20200061519 and Carbon Engineering's design around a KOH-CaCO3 process capable of generating 1 MMT or more of CO2per year (Keith et al., 2018, Joule 2(8):1573-1594). As in most current DAC systems, the CO2 recovery process requires the input of heat (Fasihi et al., 2019, J. Clean. Prod. 224:957-980). In adsorption-based systems, the most significant exergy losses come from cyclically heating and cooling both the adsorbent and the associated bulk heat exchange material and structural support. Kulkarni and Sholl 2012, Ind. Eng. Chem. Res. 51(25):8631-8645) estimated a second law efficiency of 7.4% for a typical temperature swing adsorption (TSA) DAC system, which could be improved to about 11.6% with a larger capacity adsorbent. From a detailed thermodynamic analysis provided by Keith et al. (2018) for Carbon Engineering Design, one arrives at a second law efficiency of 8.3%, including CO2 compression to 150 bar. However, this estimate does not include the full energy (or environmental) cost of providing the 4.7 tons of water consumed for every ton of CO2 produced in the process. In fact, in a recent paper by Fuhrman et al. (2020) Nat. Clim. Chang. 10:920-927, it was shown that the consumption of water from the deployment of conventional DAC technology has numerous negative economic impacts that offset to a significant extent the environmental change mitigation benefits of DAC.

[0005] One possible alternative is the moisture or humidity swing DAC process. In moisture swing adsorption (MSA), exposure to high relative humidity results in water replacing CO2 adsorbed under dry conditions (He et al., 2013 Energ. Environ. Sci. 6(2):488-493, Yang et al., 2018, Chem. Comm. 54(39):4915-4918). In theory, this process eliminates the heat transfer requirement that severely limits the thermodynamic efficiency in TSA designs. However, in the few published papers on MSA systems for DAC (Wang 2011, 45(15):6670-6675, Shi 2020, Angew. Chem. Int. Edit. 59(18):6984-7006,), little attention has been paid to the significant handling of water in the cycle, with nearly 5 moles of purified water consumed for every mole of CO2 produced (Wang et al. 2013, Phys. Chem. Chem. Phys. 15(2):504-514) or the heat transfer implications of this much water adsorption / desorption during the MSA cycle. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] U.S. Patent Application No. 20200061519 [Non-patent literature]

[0007] [Non-Patent Document 1] Keith et al., 2018, Joule 2(8):1573-1594 [Non-Patent Document 2] Fasihi et al., 2019, J. Clean. Prod. 224:957-980 Summary of the Invention [Means for solving the problem]

[0008] overview Disclosed herein is an apparatus, the apparatus comprising: (A) an atmospheric water extraction unit; (B) a direct air capture unit positioned downstream of and in communication with the atmospheric water extraction unit; Equipped with the device is capable of reversibly operating in (i) an adsorption mode to adsorb water and CO2 from an incoming air stream and (ii) a regeneration mode to release the adsorbed water and CO2; the atmospheric water extraction unit comprises a first desiccant bed comprising an adsorbent material that adsorbs water from the incoming air stream during an adsorption mode and releases water during a regeneration mode; The direct air capture unit includes a first moisture-reactive CO2 adsorbent bed comprising an adsorbent that adsorbs CO2 from the airstream during an adsorption mode and releases CO2 upon contact with water vapor during a regeneration mode.

[0009] Also disclosed herein is a method that includes operating the apparatus disclosed herein in (A) an adsorption mode to remove water and CO2 from a first air stream and (B) a regeneration mode to release the adsorbed water and CO2; The adsorption mode is (a) reducing a water content of a first air stream by contacting the first air stream with a first desiccant bed to produce a second air stream having a reduced water content relative to the first air stream; (b) reducing the CO content of the second air stream by contacting the second air stream with a first moisture-reactive CO adsorbent bed and releasing water from the bed to create a third air stream, the third air stream having a reduced CO content relative to the first and second air streams and a water content greater than the water content of the second air stream but less than the water content of the first air stream; (c) exhausting the third air stream to the ambient air; and Including, The playback mode is (a) creating a water vapor stream by releasing water adsorbed by a first desiccant bed; (b) contacting the water vapor stream with a first moisture-reactive CO2 adsorbent bed to release CO2 adsorbed by the bed and to adsorb water from the water vapor stream to produce an exhaust stream comprising water vapor and CO2; (c) passing the effluent stream through one or more condensers and compressors to produce (i) a liquid water condensate effluent and (ii) a CO2 stream; Includes.

[0010] The foregoing will become more apparent from the following detailed description, which proceeds with reference to the accompanying drawings. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a first embodiment of a hybrid direct air capture (HDAC) system disclosed herein, which utilizes atmospheric water extraction (AWE) coupled with CO2 moisture swing adsorption (MSA). This embodiment discloses both AWE and MSA in a single chamber.

[0012] [Diagram 2] FIG. 2 is a schematic diagram of the operation of a first embodiment of the HDAC system disclosed herein.

[0013] [Diagram 3] FIG. 3 is a schematic diagram of a second embodiment of a hybrid direct air capture (HDAC) system having separate chambers for the AWE and the MSA adsorbent bed.

[0014] [Figure 4] FIG. 4 is a process flow diagram depicting the required unit operations for a first embodiment of the HDAC system.

[0015] [Diagram 5]FIG. 5 is a perspective view of a radiator design for the bed disclosed herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The hybrid direct air capture (HDAC) system and method disclosed herein overcomes the biggest cost-driving barriers for conventional DAC systems: 1) complex and multiple unit operations resulting in high capital and operating costs, 2) low thermodynamic efficiency and resulting high energy consumption per ton of CO2 produced, and 3) high water consumption that can limit deployment in water scarce locations. The HDAC system and method disclosed herein captures both CO2 and water from the air. The HDAC system and method produces large amounts of portable water along with CO2, which enhances options in areas where water scarcity is an issue, provides a second source of income that improves financial returns, and expands the environmental benefits of removing CO2 from the atmosphere. The high purity water produced by the HDAC system and method can also be used directly as a feedstock for electrolysis to produce hydrogen, and the hydrogen, along with the produced CO2, can be used to produce carbon-neutral or low carbon footprint fuels. As described in detail below, the HDAC system and method disclosed herein has a small number of unit operations, thereby simplifying the overall process. In certain embodiments, the HDAC systems and methods disclosed herein have an overall CO2 capture efficiency of at least 50%, more particularly at least 60%, and an overall water removal efficiency of at least 50%, more particularly at least 65%.

[0017] HDAC combines atmospheric water extraction (AWE) with CO2 moisture swing adsorption (MSA), with the AWE providing the pure water needed to regenerate the MSA. An exemplary embodiment of such a system and method is shown in Figure 1. An operating state schematic is provided in Figure 2. Because the adsorption and regeneration cycles of the AWE and MSA adsorbents work in opposite operating states, integrating them into the HDAC provides a highly efficient means to balance the water demand required to produce CO2.

[0018] In one illustrative embodiment shown in FIG. 2, in operating state 1, water is removed from the incoming airflow by passing through a first (initial) desiccant bed. In an embodiment, sufficient water is removed to reduce the relative humidity (RH) of the airflow to preferably between 25% RH and 15% RH from ambient RH. The relatively dry airflow is now passed through a water-reactive CO2 adsorbent for CO2 removal. The dry airflow removes water from the MSA, thus restoring the affinity of the MSA for capturing CO2. In an embodiment, 40 to 50%, more specifically 60 to 70%, of the CO2 is removed by the water-reactive CO2 adsorbent. If desired, water released from the CO2 adsorbent to the atmosphere can be recaptured in a second desiccant bed containing a recuperative desiccant designed for extracting water vapor from low RH air.

[0019] In the opposite chamber (FIG. 1), operating in operational state 2, a partial vacuum is applied. A vacuum pressure between 10 mbar and 50 mbar is applied depending on the ambient air temperature. Water vapor is released from the desiccant and flows through the CO2 sorbent bed. A portion of the water (typically <10%) is adsorbed by the moisture-reactive sorbent and CO2 is released to form a mixture of water vapor and CO2. Water is also released from the recovery sorbent, if a recovery sorbent is used in the system. This gas mixture is then drawn by the first vacuum pump to a condenser where most of the water is condensed. The remaining CO2 + water vapor stream is compressed by the vacuum pump and passed to a second condenser stage to remove additional water. After one additional compression-condensation stage, the CO2 stream is passed through a dehydrator to remove enough of the remaining water to achieve the commercial pipeline specification of <500 ppmv water. The dried CO2 is compressed to below the desired pipeline pressure, for example between 60 bar and 100 bar. At the end of the regeneration cycle, the chambers in operating state 2 are switched to operating state 1 and the chambers in operating state 1 are switched to operating state 2. The cycle time for the system can range between 90 seconds and 1200 seconds, with a preferred cycle time being 300 seconds to 600 seconds.

[0020] In a second embodiment shown in Figure 3, there is a first section housing a desiccant bed and a second section housing an MSA bed, the first and second sections being physically separated from each other. This embodiment is advantageous if the MSA is capable of generating higher CO2 pressures (e.g. 360 mbar), thus reducing the compression force for the CO2. In this embodiment, water vapor from the second stage vacuum pump is cooled and then injected into a separate DAC chamber to provide the water required for CO2 removal from the MSA.

[0021] Atmospheric Water Extraction (AWE) Section The AWE section of the system disclosed herein includes one or more nanostructured dry porous materials configured to absorb water from an air inlet stream at a first pressure and release water from the material when exposed to a second pressure, the second pressure being lower than the first pressure. A preferred embodiment for the first pressure is ambient air pressure and the second pressure is a partial vacuum between 10 mbar and 50 mbar depending on the ambient air temperature. A second embodiment has the first pressure above ambient, such as, for example, 2 bar to 4 bar, while the second pressure is ambient pressure.

[0022] Preferably, the desiccant material is located within a structural support, such as a desiccant bed, but other configurations are envisioned in certain applications, including 3D arrangements including rods, coatings on fins, or configurations of other structures. A number of these structures can be interconnected, with or without connections to other features, such as heat pipes, heat exchange tubes, or seals. Desiccants with various adsorption properties can be assembled in sequence along the air flow path to optimize water extraction from the airflow. In a preferred embodiment, a vacuum pump is connected to the system and adapted to provide sufficient suction to the desiccant material to reduce the pressure and remove the water from the desiccant, resulting in regeneration of the adsorption material. In a second embodiment, an air compressor is used to supply air at a first pressure, which flows under pressure through the desiccant bed. An expander can be included to recover some of the compression energy from the exhaust. Regeneration occurs at a second pressure, which can range between 100 mbar and ambient atmospheric pressure.

[0023] In some embodiments, the dry material can be a metal-organic framework (MOF) material, a zeolite, a mesoporous silica, a covalent organic framework material, a porous organic polymer, or a porous carbon.

[0024] MOFs are porous metal-organic frameworks or hybrid organic-inorganic materials that contain at least one metal component selected from the group consisting of Zn, Fe, Al, Mg, V, Ni, Mn, Co, Sc, Y, Ti, Zr, Hf, Nb, Ta, Cr, Mo, W, Tc, Re, Ru, Os, Ir, Pd, Pt, Cu, Ag, Au, Hg, Sr, Ba, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, Bi, and combinations thereof.

[0025] Ni +2 , Zn +2 , Cu +2 , Co +2 , Mg +2 , Ca +2 , Fe +2 , Mn +2 Divalent metal ions, including, for example, Fe +3 , Al +3 , Cr +3 , Mn +3 In another embodiment, the porous metal-organic framework can be formed by coordination with tetravalent, pentavalent, or hexavalent metal ions of Zr, Ti, Sn, V, W, Mo, or Nb.

[0026] In some embodiments, mixed metals containing monovalent metal ions as well as divalent and trivalent oxidation states are represented by M +3 3[M +2 The metal-organic framework, also known as a Prussian blue analogue with the formula [(CN)6]2, was incorporated into the M +3 is Fe +3 , CO +3 , Mn +3 etc., M +2 Zn +2 , Ni +2 , Co +2 , Mn +2 , Cu +2 etc., and mixtures thereof.

[0027] The organic components in the porous metal-organic framework material are referred to as linkers or organic linkers. In one embodiment, the organic linkers have functional groups capable of coordination. Examples of functional groups that can coordinate with these metal ions are carbonate (-CO3H), the anionic form of carbonate (-CO3H), and the like. - ), carboxyl anion of carboxylic acid, amino group (-NH2), imino group, hydroxyl group (-OH), amide group (-CONH2), sulfonic acid group (-SO3H), anionic form of sulfonic group (-SO3), cyanide group (-CN), nitrosyl group (-NO), and pyridine. For example, in one embodiment, the chemical formula T[Fe(CN)5NO] (where T is Mn, Fe, Co, Ni, Cu, Zn, and Cd) and the mixed composition include Co, also known as nitroprusside. 1-x T x [Fe(CN)5NO] (T includes Mn, Fe, Ni, Zn, and Cd).

[0028] In some embodiments, the organic ligands may include compounds having at least two sites for coordination (e.g., bi-, tri-, tetra-, penta-, and hexadentate ligands). Non-limiting examples of these organic compounds may be neutral linkers such as pyrazine, dabco, piperazine, bipyrazine, azobenzene, and functionalized versions of these neutral ligands, and anionic organic compounds include anions of carboxylic acids such as terephthalate, naphthalene dicarboxylate, benzene tricarboxylate, benzene tetracarboxylate, benzene pentacarboxylate, benzene hexacarboxylate, dioxo-terephthalate, and the like. Aromatic anions and other linear carboxylate anions include formate, oxalate, malonate, succinate, glutamate, and the like, and non-aromatic carboxylate anions including 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and 1,3,5 cyclohexanetricarboxylic acid can be used to prepare hybrid organic-inorganic materials.

[0029] Other organic linkers include a variety of heterocyclic materials including furan, indole, pyridine-2,3-dicarboxylate, pyridine 2,6-dicarboxylic acid, pyridine 2,5-dicarboxylic acid, and pyridine-3,5-dicarboxylic acid.

[0030] Other organic linkers for producing a subclass of metal-organic frameworks called zeolitic imidazolate frameworks have been generated using imidazolates, tetrazoles, and triazoles and functionalized with Cl, Br, I, F, NH2, and NO2.

[0031] In another embodiment, the organic ligand can be dihydroxyterephthalate and its derivatives. As a non-limiting example, dihydroxyterephthalate has chloro, bromo, iodo, fluoro, cyano, sulfone, amino, aldehyde, and carbamide. Similarly, the organic component can be functionalized with di-, tri-, tetra-, or pentane terephthalate containing at least one or more functional groups such as nitro, amino, bromo, chloro, iodo, or amino.

[0032] In one embodiment, the desiccant comprises a covalent organic framework. Covalent organic frameworks (COFs) or porous aromatic frameworks (PAFs) or porous polymer networks (PPNs) are porous crystalline extended aromatic framework materials in which organic components are linked by strong covalent bonds. The attraction behind these materials has been solely the use of light elements such as H, B, C, N, and O, which are known to form stable materials with strong covalent bonds (e.g. graphite, diamond, boron nitride). The fine-tunability (even down to size) of the organic components with various functional groups results in lightweight functionalized micro / mesoporous covalent structures with desirable applications. Covalent organic framework type materials include those produced by condensation of diboronic acid, hexahydroxytriphenylene, dicyanobenzene, and its derivatives of formula CHBO, as well as those produced from benzene-1,4-diboronic acid (BDBA), 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP), tetrakis(4-bromophenyl)methane, tetrakis(4-ethynylphenyl)methane (TEPM), 1,3,5,7-tetrakis(4-ethynylphenyl)adamant (TEPA), 1,3,5,7-tetrakis(4-bromophenyl)adamant (TBPA).

[0033] In certain embodiments, the desiccant is MOF 303, MOF 801, or MOF 841, with MOF 303 or MOF 801 performing best in some circumstances. MOF 303 is an aluminum-based MOF. MOF 801 and MOF 841 are zirconium-based MOFs.

[0034] A preferred embodiment provides pairs or sets of desiccant beds or other structures within the air passageways that allow contact between moist air and desiccant material. The air is constantly dried as it moves across these structures. This can allow for continuous drying and increased efficiency through the use of different desiccants that more effectively adsorb water from air at higher relative humidity versus others that are more effective at lower relative humidity. Additionally, the passageways to these structures can be opened and closed, allowing one section to be set up to be in dehumidifying operation at a first operating pressure while water is removed from the system and the desiccant regenerated at a second operating pressure in another section.

[0035] Water adsorbed by the desiccant material spontaneously results in the production of heat, which can be as much as 3000 kJ / kg-H2O, or even more with some desiccants. When water is removed from the desiccant during regeneration, an equal and opposite amount of heat is consumed. In a preferred embodiment, the heat of adsorption is used to enhance the regeneration of the desiccant material by providing the heat required during regeneration at the second operating pressure in the device. Heat can be transferred to these materials passively through interconnected heat pipes, or actively by pumping a heat transfer fluid through tubes, plates, pipes, or other means of conveying the heat transfer fluid from the part of the system experiencing adsorption to the bed or structure experiencing regeneration. In a preferred embodiment, the desiccant material is bonded to a thermally conductive support, such as aluminum, which provides 1) efficient transport of the heat of adsorption / desorption to the heat pipes or other heat transfer systems used to interconnect the parts of the system, and 2) efficient exposure of the desiccant material to airflow to increase the rate of water absorption.

[0036] FIG. 5 shows an example of a tube-fin design desiccant bed system, which is formed similarly to a radiator with a set of thermally conductive fins made of a very lightweight material such as aluminum coated with a desiccant. As air flows through the channels between the fins and water is adsorbed by the desiccant generating heat, the tubes carry the heat transfer fluid to a header that is connected to an identical set of desiccant beds, which undergo regeneration and thus consume heat. Heat transfer simulations of this design show that with sufficient flow rate of heat transfer fluid, the temperature difference between the chambers can be kept below 5° C. This confirms the design premise in that the adsorption-desorption chambers can be thermally coupled and the AWE system can be operated approximately isothermally.

[0037] Direct Air Capture (DAC) Section In a preferred embodiment of the HDAC, the isothermal AWE section described in US Patent Application Publication No. 2021 / 0055010 and discussed above is used to provide water vapor to perform a humidity swing to release CO2 from the moisture-reactive adsorbent. In one embodiment illustrated in FIG. 1, the HDAC system design merges the AWE with the MSA into two chambers or trains, with the first train 1 capturing water and CO2 from the air flow while the second opposing train 2 is being regenerated. This utilizes the heat exchange principles already described in the AWE section to provide continuous production of CO2 and water and balance the heat demand between the chambers. A similar heat balancing method can be used in the DAC section, but there is little benefit to implementing this heat exchange method in the DAC section since the heat of adsorption of CO2 is typically only about 1100 kJ / kg-CO2, a much smaller CO2 mass flow rate compared to water.

[0038] The following are dispersed within each of the first and second chambers: 1) a desiccant bed consisting of one or more desiccant materials dispersed on a thermally conductive support, 2) a water-reactive CO2 adsorbent, and 3) optionally, a recovery desiccant. The recovery desiccant is used to capture water vapor liberated from the MSA during its regeneration phase. In an embodiment, each of the first and second chambers can be an annular passage through which air flowing therethrough can contact the initial desiccant, the water-reactive CO2 adsorbent, and (if present) the recovery desiccant. The first and second chambers can be arranged such that they are parallel to one another.

[0039] The first desiccant, water-responsive CO2 adsorbent, and recovery desiccant (if present) are positioned relative to the location of the airflow inlet such that incoming air flows through the first or second chamber in the following order: first desiccant, optional second desiccant (if used), water-reactive CO2 adsorbent, and recovery desiccant (if present). In other words, the first desiccant is closest to the airflow inlet, the recovery desiccant (if present) is closest to the air outlet, and the water-reactive CO2 adsorbent is located between the first desiccant and the recovery desiccant.

[0040] The apparatus includes at least one air flow inlet. An air flow diverter may be disposed at the air flow inlet to direct the incoming air flow into either the first chamber or the second chamber depending on the regeneration status of the initial desiccant and the water-reactive CO2 adsorbent, respectively.

[0041] The device includes at least one exhaust port. The air that has been passed through the initial desiccant and water-reactive CO2 adsorbent is exhausted from the device via the exhaust port.

[0042] To perform regeneration, the preferred embodiment implements a seal on one chamber to which a vacuum is applied. The seal can be formed using any of a variety of methods, including swinging, sliding, or rotating a door to seat against a sealing material such as an O-ring, gasket, flange, or other sealing material. In an example of one embodiment that allows for switching the seal between chambers to cycle operating conditions, a vacuum applied to the chamber with the door seated against the seal causes compression of the door and sealing material to form an airtight seal. After purging the remaining air from the chamber, a drop in pressure causes the water vapor to desorb from the desiccant. By installing an inlet manifold at the top of the chamber and distributing the inlet vapor flow, the water vapor flow from the desiccant can be distributed evenly through the MSA bed. A portion of the water vapor (usually <10%) is adsorbed by the MSA. The adsorption process liberates CO2 from the MSA, which then flows back into the manifold with the remaining water vapor and is removed from the chamber by a vacuum pump.

[0043] As illustrated in the process flow diagram (FIG. 4) in a preferred embodiment, the water vapor and CO2 mixture is first passed through a condenser to remove a significant proportion of water from the stream. In an exemplary condenser design implementing a microchannel heat exchanger architecture where the water vapor flows into a header, the water vapor is then distributed into channels that decrease in width to 1 mm or less. A single plate is formed into a stack with multiple channels sufficient to accommodate the design baseline water production from the HDAC system. The steam entering the header is cooled in the channels that allow condensation to occur. The condensate and steam are discharged from the condenser and separated by gravity. The steam is then compressed and passed through a second condenser (Cond1) operating at a higher pressure. Additional water vapor is condensed in Cond2. Additional compression condensation stages can be included as shown in FIG. 4 to further reduce the water content in the CO2 stream. As shown in FIG. 4, a series of water pumps are used to increase the pressure of the condensate to below atmospheric pressure for discharge. This step consumes little energy due to the incompressibility of liquid water.

[0044] If desired prior to compression to higher pressures, such as for pipeline transport, a drying system such as drierite or triethylene glycol can be implemented to remove the remaining water vapor sufficiently to achieve pipeline specifications of <500 ppmv water. If compression to high pressures (60 bar to 100 bar) is required, as illustrated in Figure 4, this step can be performed using any commercial multi-stage CO2 compression system.

[0045] In another embodiment shown in Figure 3, the MSA bed can be installed in a chamber or section separate from the desiccant bed. This arrangement can have energy consumption benefits if the MSA adsorbent can generate slightly higher CO2 pressures (e.g., between 100 mbar and 300 mbar) during regeneration. In this embodiment, water vapor is provided from the AWE section after at least two compression-condensation stages to match the CO2 pressure being generated by the MSA.

[0046] In certain embodiments, the MSA CO2 adsorbent comprises a hierarchical porous material functionalized with quaternary ammonium groups.

[0047] A preferred embodiment of the MSA material utilizes a porous material that is first functionalized with amine groups. The amine functional groups in the porous material are then converted to quaternary ammonium species by post-synthesis modification via alkylation reactions or other established methods. In a preferred embodiment, the equilibrium MSA loading at 25° C. in 420 ppmv CO2 air is at least 0.3 mmol / g to 0.5 mmol / g, more specifically, 0.8 mmol / g to 2 mmol / g.

[0048] The porous material may be macroporous (pore size greater than 50 nm), mesoporous (having a pore size or pore size distribution between 2 nm and 50 nm), microporous (having a pore size or pore distribution smaller than 2 nm), or any combination of macroporous, mesoporous, or microporous pore distribution.

[0049] The porous materials described herein can be characterized as having two or more continuous phases (e.g., a void phase and a solid phase). The two or more phases are generally interdigitated, whereby the two or more phases interpenetrate. The solid phase can be inorganic, organic, or a combination of the two.

[0050] In some embodiments, substantially all of the pores in a porous material are open pores and substantially no closed pores. Closed pores are defined as pores that are completely surrounded by solid material, and open pores are defined as pores that are not completely surrounded by solid material. Thus, in an open pore material (i.e., a porous material in which substantially all of the pores in the porous material are open pores), substantially all of the pores in the material are part of a continuous void phase.

[0051] In one embodiment, the moisture reactive CO2 sorbent material is dispersed on a substrate, such as, for example, a fiber or a nonwoven mat.

[0052] In other embodiments, the moisture reactive CO2 adsorbent may be formed as a chemically homogenous structural adsorbent material made entirely from the moisture reactive CO2 adsorbent. Such structural adsorbents may be in fiber format, monolith format, or any number of architectures formed by suitable manufacturing processes.

[0053] In view of the many possible embodiments to which the principles of the disclosed invention may be applied, it should be recognized that the illustrated embodiments are merely preferred examples of the invention and should not be considered as limiting the scope of the invention.

Claims

1. An apparatus, comprising: (A) an atmospheric water extraction unit; (B) a direct air capture unit positioned downstream of and in communication with the atmospheric water extraction unit; Equipped with The apparatus comprises: (i) extracting water and CO from an incoming air stream; ２ and (ii) the adsorption mode for adsorbing the adsorbed water and CO ２ and a regenerative mode for releasing the the atmospheric water extraction unit comprises a first desiccant bed comprising an adsorbent material that adsorbs water from the incoming air stream during an adsorption mode and releases water during a regeneration mode; The direct air capture unit includes a first moisture-reactive CO2 absorbent. ２ a sorbent bed, the sorbent being adapted to absorb CO from the air stream during the adsorption mode; ２ During regeneration mode, when it comes into contact with water vapor, it adsorbs CO ２ A device that releases

2. (A) the atmospheric water extraction unit further comprises a second desiccant bed, the second desiccant bed comprising an adsorbent, the adsorbent adsorbing water from the incoming airstream during an adsorption mode and releasing water during a regeneration mode; (B) the direct air capture unit is adapted to capture a second moisture-reactive CO ２ The second moisture-reactive CO2 adsorbent bed further comprises a sorbent, the sorbent being adapted to adsorb CO from a stream adsorption mode. ２ During regeneration mode, when it comes into contact with water vapor, it adsorbs CO ２ Release The apparatus further comprises a first desiccant bed and a first moisture-reactive CO ２ The adsorbent bed forms a first train, the second desiccant bed and the second moisture-reactive CO ２ the adsorbent beds are configured to form a second train separate from the first train; The first train and the second train are configured to (i) extract water and CO from an incoming air stream; ２ and (ii) the adsorption mode for adsorbing the adsorbed water and CO ２ and a regenerative mode for releasing the the first train and the second train are configured such that the first train operates in an adsorption mode when the second train operates in a regeneration mode, and the second train operates in an adsorption mode when the first train operates in a regeneration mode.

2. The apparatus of claim 1.

3. 3. The apparatus of claim 2, wherein the first desiccant bed is thermally coupled to the second desiccant bed.

4. The atmospheric water extraction unit and the direct air capture unit are configured to convert water adsorbed by the first desiccant bed during an adsorption mode into adsorbed CO ２ During a regeneration mode for releasing the first moisture-reactive CO ２ The apparatus of claim 1 configured to contact a sorbent bed.

5. The first train and the second train are configured to convert water adsorbed by the first desiccant bed or the second desiccant bed during an adsorption mode into adsorbed CO ２ During a regeneration mode for releasing the first moisture-reactive CO ２ Adsorbent bed or the second moisture-reactive CO ２ The apparatus of claim 2 configured to contact a sorbent bed.

6. The first moisture-reactive CO ２ downstream of the adsorbent bed. ２ 10. The apparatus of claim 1, further comprising a first recuperative desiccant bed disposed in communication with the adsorbent bed.

7. The first moisture-reactive CO ２ downstream of the adsorbent bed. ２ a first recuperative desiccant bed disposed in communication with the adsorbent bed; and ２ downstream of the adsorbent bed. ２ 3. The apparatus of claim 2, further comprising a second recuperative desiccant bed disposed in communication with the adsorbent bed.

8. 10. The apparatus of claim 1, wherein the first desiccant bed comprises a nanostructured porous material that adsorbs water from an air stream at a first pressure and releases the water when exposed to a second pressure, the second pressure being less than the first pressure.

9. 3. The apparatus of claim 2, wherein the first desiccant bed and the second desiccant bed comprise a nanostructured porous material that adsorbs water from an air stream at a first pressure and releases water when exposed to a second pressure, the second pressure being less than the first pressure.

10. 10. The apparatus of claim 8 or claim 9, wherein the nanostructured porous material comprises a metal-organic framework material.

11. 11. The device of claim 10, wherein said metal-organic framework material is selected from the group consisting of Fe-MIL-100, MOF-303, MOF-801, MOF-841, and combinations thereof.

12. 7. The apparatus of claim 6, wherein the first recuperative desiccant bed comprises a nanostructured porous material that absorbs water from an airflow at a first pressure and releases water when exposed to a second pressure, the second pressure being less than the first pressure.

13. 8. The apparatus of claim 7, wherein the first and second recuperative desiccant beds comprise a nanostructured porous material that absorbs water from an airflow at a first pressure and releases water when exposed to a second pressure, the second pressure being less than the first pressure.

14. 14. The apparatus of claim 12 or claim 13, wherein the nanostructured porous material comprises a metal-organic framework material.

15. 13. The device of claim 12, wherein said metal-organic framework material is selected from the group consisting of Fe-MIL-100, MOF-303, MOF-801, MOF-841, and combinations thereof.

16. The first moisture-reactive CO ２ 10. The apparatus of claim 1, wherein the adsorbent bed comprises a porous carbon material functionalized with quaternary ammonium groups.

17. The first moisture-reactive CO ２ an adsorbent bed and the second moisture-reactive CO ２ The apparatus of claim 2 , wherein the adsorbent bed comprises a porous carbon material functionalized with quaternary ammonium groups.

18. The apparatus of claim 2 , wherein the first train and the second train are sealed from each other.

19. 4. The apparatus of claim 3, wherein at least one heat exchange pipe thermally couples the first desiccant bed to the second desiccant bed.

20. 3. The apparatus of claim 2, further comprising a vacuum source in alternating communication with the first desiccant bed and then with the second desiccant bed.

21. The first moisture-reactive CO ２ adsorbent bed and then the second moisture-reactive CO ２ CO in alternating communication with the adsorbent bed ２ 21. The apparatus of claim 20, further comprising a compressor.

22. First moisture-reactive CO ２ downstream of the adsorbent bed. ２ a condenser positioned in communication with the adsorbent bed; a vacuum pump positioned downstream of and in communication with the condenser; and a CO 2 pump positioned downstream of and in communication with the vacuum pump. ２ 10. The apparatus of claim 1 further comprising a compressor.

23. (A) Water and CO from a first air stream ２ and (B) adsorption mode to remove adsorbed water and CO ２ and a regeneration mode for releasing said The adsorption mode is (a) reducing a water content of the first airflow by contacting the first airflow with a first desiccant bed to produce a second airflow having a reduced water content relative to the first airflow; (b) circulating the second airflow through the first moisture-reactive CO ２ The CO2 of the gas stream is removed by contacting it with an adsorbent bed. ２ and creating a third airflow by reducing the CO content and releasing water from the bed, the third airflow having a reduced CO content relative to the first airflow and the second airflow. ２ a water content greater than the water content of the second air stream but less than the water content of the first air stream; (c) exhausting the third air stream to the ambient atmosphere; Including, The playback mode is (a) creating a water vapor flow by releasing water adsorbed by the first desiccant bed; (b) converting the water vapor stream into the first moisture-reactive CO ２ by contacting the bed with the CO adsorbed by said bed. ２ and adsorbing water from the water vapor stream, ２ producing an exhaust stream comprising: (c) passing said effluent stream through one or more condensers and compressors to produce (i) a liquid water condensate effluent and (ii) a CO ２ Creating flow and A method comprising:

24. The device includes a first moisture-reactive CO ２ downstream of the adsorption bed, the first moisture-reactive CO ２ 24. The method of claim 23, further comprising a first recuperative desiccant bed disposed in communication with the adsorption bed, the method further comprising reducing the water content of the third air stream by contacting the third air stream with a recuperative desiccant bed prior to exhausting the third air stream to the ambient atmosphere.

25. 24. The method of claim 2 comprising operating the apparatus of claim 2 such that the first train operates in an adsorption mode when the second train operates in a regeneration mode and the second train operates in an adsorption mode when the first train operates in a regeneration mode.

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