Carbon capture sorbents with moisture control additives

Abstract

Provided herein are sorbent compositions comprising moisture control additives for use as a sorbent for carbon capture are disclosed and methods of capturing carbon using the sorbent compositions disclosed herein. Provided are also methods of producing and regenerating the sorbent compositions herein.

Description

34037-20002.40 CARBON CAPTURE SORBENTS WITH MOISTURE CONTROL ADDITIVES CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application Nos. 63 / 626,474, filed January 29, 2024, 63 / 558,562, filed February 27, 2024, 63 / 562,854, filed March 8, 2024, each of which is incorporated herein by reference in their entirety. FIELD

[0002] The present disclosure relates generally to sorbent compositions that are stable at high humidities, systems and methods of using said sorbent compositions for carbon capture, and methods of preparation thereof. BACKGROUND

[0003] Solid carbonate sorbent is a promising carbon dioxide (CO2) capture technology due to its low cost and toxicity. However, current carbon capture technologies using deliquescent solid carbonate sorbents (e.g., solid sorbents that readily absorb moisture from the surrounding gaseous environment air and dissolve into a solution when the relative humidity reaches a certain level) suffer from unstable sorbent mechanical structure when exposed to highly humid gas environments, such as flue gas comprising CO2. When exposed to humidity, deliquescent solid sorbents absorb water, which can decompose the sorbent material structure and reduce the sorbent’s CO2 sorption capacity. In such cases, the sorbent begins fuse together and becomes difficult to replace or remove during maintenance and repair of the reactor used for carbon capture.

[0004] Currently, one method of circumventing the aforementioned issues with the use of deliquescent solid sorbents is to employ a dehydration step of the humid flue gas before the flue gas is contacted with the sorbent material to reduce the moisture of the flue gas. Other methods include the use of sorbents with insoluble active ingredients, such as amine, or insoluble substrates, such as zeolite and activated carbons which are used to prepare sorbents via impregnation techniques, due to their high stability under humid environments. However, such techniques restrict the selection of ingredients of the sorbent and limit the weight percent of the active ingredient(s) in the sorbent due to the weight of the insoluble substrate.

[0005] Additionally, current carbon capture chemisorption technologies are energy intensive, with the lowest theoretical energy consumption at 3.5 GJ / tonne-CO2 prior to incorporating heat recovery. For example, hot potash solution technology has a heat of reaction 1sf-625386234037-20002.40 of 12 GJ / tonne-CO2, and an additional 3 GJ / tonne-CO2 of sensible heat required to swing the temperature of the solution; amine solution technology has a heat of reaction of 2.5 GJ / tonne- CO2, and an additional 1.4 GJ / tonne-CO2 of sensible heat required to swing the temperature of the solution; dry potassium carbonate technology has a heat of reaction of 3.2 GJ / tonne-CO2, and an additional 0.3 GJ / tonne-CO2 of sensible heat required to swing the temperature of the potassium carbonate solid. The lowest combined energy required to capture carbon dioxide from a gas mixture is 3.5 GJ / tonne-CO2 among the technologies described above, prior to the incorporation of heat recovery or other engineering methods.

[0006] Moisture swing of potassium carbonate can potentially achieve 1 GJ / tonne-CO2, but has not been applied in a scalable process due to engineering challenges. Moisture swing of potassium carbonate has been proposed in concept as a potential method for carbon capture due to its low theoretical energy consumption. The reaction can be written as follows: ^^^^2^^^^^^^^3 ∙ 1.5^^^^2^^^^ + ^^^^^^^^2 ↔ 2^^^^^^^^^^^^^^^^3 + 0.5^^^^2^^^^

[0007] The energy of reaction is approximately 1 GJ / tonne-CO2. However, this reaction has not been successfully applied in a scalable process due to engineering challenges, which include sorbent deliquescence under engineering operation conditions, and control of moisture such that the carbonate salt stays as a hydrate while the bicarbonate product is anhydrous.

[0008] Current reactor packing material (i.e., sorbent) for CO2 capture can be made from a variety of methods including chemical synthesis or mechanical assembly. Chemical synthesis typically requires a few precursors to react and produce the desired form of the CO2 reactor sorbent. The precursors typically need to be purchased separately, making the raw material costs high. Mechanical assembly of sorbent for CO2 capture starting from the desired chemical form have lower raw material costs, but the chemical performance and stability of the resulting sorbent have been less desirable. The sorbent produced using both methods may contain one or more deliquescent or soluble components that partially dissolve and recrystallize during normal operation (i.e., sorption then desorption of CO2 cycles during carbon capture), which then stick to the reactor walls and / or adjacent sorbent, and become difficult to remove during maintenance of the reactor.

[0009] Thus, there is a need for improved solid deliquescent sorbent compositions that are structurally stable when exposed to highly humid gas environments, such as flue gas comprising CO2, and simple, low-cost methods for producing the same. Additionally, there is a 2sf-625386234037-20002.40 need in the art for systems and methods of carbon capture that are more efficient and less energy intensive than current carbon capture technologies. BRIEF SUMMARY

[0010] In some aspects, provided herein is a sorbent composition for carbon capture, comprising: an active component for CO2 chemisorption; a moisture control additive; and a support material.

[0011] In some aspects, provided herein is a method of producing a sorbent composition for carbon capture, comprising: mixing chemical feed powders in a solvent to produce a mixture, wherein the chemical feed powders comprise an active component for CO2 chemisorption and a support material; extruding the mixture to produce an extruded product; drying the extruded product to produce a dry extruded product; crushing the extruded product to produce a crushed product; and sieving the crushed product to produce sorbent granules.

[0012] In some aspects, provided herein is a system for capturing and discharging CO2, comprising: a CO2 source configured to output a gaseous CO2 stream; a reactor configured to receive the gaseous CO2 stream, wherein the reactor comprises a sorbent composition, wherein the sorbent composition comprises an active component for CO2 chemisorption, a moisture control additive, and a support material, wherein the gaseous CO2 stream contacts the sorbent composition; and a first gaseous outlet configured to output a gaseous stream, wherein the gaseous stream comprises a lower concentration of CO2 than the gaseous CO2 stream.

[0013] In some aspects, provided herein is a method of capturing CO2, comprising contacting a gaseous CO2 stream with a sorbent composition to absorb CO2, wherein the sorbent composition comprises an active component for CO2 chemisorption, a moisture control additive, and a support material. DESCRIPTION OF THE FIGURES

[0014] The present application can be understood by reference to the following description taken in conjunction with the accompanying figures.

[0015] FIG.1 shows a method of manufacturing packing (i.e., sorbent) via a mixing- drying-crushing-sieving procedure where the raw materials (and solvents) in powder or liquid forms are mixed in a mixer. The mixture is then dried in a dryer to remove extra solvent and to harden. The hardened material is subsequently crushed to small pieces, and then sieved to produce reactor packing within a specified size range. 3sf-625386234037-20002.40

[0016] FIG.2 shows a flow diagram illustrating an exemplary carbon capture system, according to some embodiments described herein.

[0017] FIG.3 shows an illustration of a carbon capture system (200), according to some embodiments described herein.

[0018] FIG.4 shows an absorption profile of a sorbent composition in a packed bed reactor.

[0019] FIG.5 shows an absorption profile or a sorbent composition without the use of a pretreatment step.

[0020] FIG.6 shows the ratio of the partial pressure of CO2 to the partial pressure of argon (internal standard to quantify CO2) and the reactor temperature over time during low temperature regeneration of a sorbent composition.

[0021] FIG.7 shows the CO2 capture performance of fresh and rejuvenated sorbent compositions according to some embodiments described herein.

[0022] FIG.8 shows the temperature swing carbon capture using a sorbent according to some of the embodiments described herein at controlled humidity of 7.8% by volume and a CO2 concentration of 3.7% by volume. DETAILED DESCRIPTION

[0023] The following description sets forth exemplary compositions, methods, systems, parameters and the like. It should be recognized, however, that such description is not intended as a limitation on the scope of the present disclosure but is instead provided as a description of exemplary embodiments.

[0024] The present invention encompasses the surprising discovery that solid sorbent compositions comprising moisture control additives have increased mechanical structure stability in moist and / or humid environments, such as humid flue gas, while retaining their chemical activity for carbon capture, and allow for carbon capture and related regeneration steps to be performed via a modified temperature swing adsorption process which utilizes less energy than other carbon capture methods known in the art.

[0025] In some aspects, provided herein are sorbent compositions comprising moisture control additives which stabilize the sorbent structure during carbon capture. 4sf-625386234037-20002.40

[0026] In some aspects, provided herein are system and methods for moisture swing of potassium carbonate. In some embodiments, provided herein is a modified temperature swing adsorption process with moisture control to achieve the moisture swing reaction in a scalable process. In some embodiments, the overall thermal energy requirement is approximately 1.2 GJ / tonne-CO2 without heat recovery, and 0.36-0.84 GJ / tonne-CO2 with heat recovery.

[0027] In some aspects, provided are systems and methods for carbon capture using solid sorbent compositions comprising a moisture control additive via a modified temperature swing adsorption reaction. In some aspects, provided are methods for modifying the surface of a carbon capture reactor to prevent sticking of the sorbent to the reactor walls. In some variations, “carbon capture” as used herein refers to the separation of CO2 from a CO2- containing gas (“a gaseous CO2 stream”) to produce an enriched CO2 stream (a gaseous stream with a higher CO2 concentration than the gaseous CO2 stream) and a CO2-lean stream (a gaseous stream with a lower CO2 concentration than the gaseous CO2 stream).

[0028] In some aspects, provided are methods of producing sorbent compositions using a wet granulation method. In some aspects, provided are methods of rejuvenating spent sorbent used for carbon capture.

[0029] In some aspects, provided are sorbent compositions including on or more additives that chemically or physically uptake gaseous or liquid water above target humidity in order to control the chemical activity of water in the local environment. In some embodiments, the reduced activity of water in turn leads to lower instability of the sorbent. For example, in some variations, sorbent fusing or dissolution is minimized when coupled with controlled process variables such as temperature, pressure and contact time between the sorbent and the moist environment. In some embodiments, for example, common additives for moisture control include desiccants (also referred to herein as “moisture control additives”) that uptake moisture at near 0% relative humidity: calcium chloride, zeolite, silica gel, etc. In some embodiments, materials that uptake moisture at elevated relative humidity include magnesium aluminosilicate, etc. In some embodiments, the inclusion of the moisture control additive(s) in the sorbent may be accomplished via: (1) Dissolving or suspending the moisture control additive(s) in the impregnation solution for porous supports; (2) Covalently link the moisture control additive(s) with porous supports; and / or, (3) Adding the moisture control additive(s) as ingredient(s) in the mixing step for bottom-up manufactured sorbents (4) Add the precursors of the moisture control additive(s) in the synthesis mixture for bottom-up synthesized sorbents. 5sf-625386234037-20002.40

[0030] In some aspects, provided herein are processes to achieve carbon capture via the following chemical reaction E-0: ^^^^2^^^^^^^^3 ∙ 1.5^^^^2^^^^(^^^^) + ^^^^^^^^2(^^^^) ↔ 2^^^^^^^^^^^^^^^^3(^^^^) + 0.5^^^^2^^^^(^^^^) (E-0)

[0031] In some embodiments, the process is a modified temperature swing adsorption withmoisture control to maintain the hydration states of ^^^^2^^^^^^^^3 ∙ 1.5^^^^2^^^^(^^^^) and ^^^^^^^^^^^^^^^^3(^^^^) in atleast the majority (timewise) of operation of the process. In some embodiments, the operation of the temperature swing in each reactor proceeds in the following order: (1) Chemisorption of CO2 takes place where the chemical reaction E-0 proceeds in the forward direction; (2) Temperature in the reactor ramps up in preparation for the regeneration reaction; (3) regeneration reaction takes place where the chemical reaction E-0 proceeds in the reverse direction; (4) Drying of the reactor takes place to remove excess moisture from the reactor and evacuate CO2 from the reactor to prevent re-absorption during the temperature ramp-down step; (4) Temperature in the reactor ramps down in preparation for another cycle of absorption. In some variations, chemisorption of CO2 comprises the introduction of a gas mixture into a carbon capture reactor and stripping the gas of CO2. In some variations, the regeneration step comprises release of CO2 from the reactor and CO2 is sent to downstream purification, compression, storage and / or transport.

[0032] In some embodiments, the process described herein maintains the hydration state of^^^^2^^^^^^^^3 ∙ 1.5^^^^2^^^^(^^^^) in steps 1, 3, 4, 5 and the hydration state of ^^^^^^^^^^^^^^^^3(^^^^) in steps 1 through 3by utilizing engineering tools. In some variations, during step 1: moisture control of the gas mixture flowing into the reactor by controlling the temperature and relative humidity of the incoming gas mixture, remove or add moisture using engineering unit operations, and / or controlling the temperature of the reactor using external heating or cooling is utilized. In some variations, during step 2: an internal heating loop where a heater (electrical resistive heater or heat exchanger), an in-line fan and the reactor of interest are connected in series to ramp up the temperature of the reactor without introducing external gases is utilized. In some variations, during step 2: gases in the internal loop may be vented to downstream processing or the atmosphere to control the pressure in the loop. In some variations, during step 2: an external heating method where a heater (electrical resistive heater or heat exchanger), an in-line fan and the reactor of interest are connected in series to ramp up the temperature of the reactor by introducing external gases is utilized. In some variations, during step 2: the temperature at theend of the ramp-up shall be such that the hydrated form ^^^^2^^^^^^^^3 ∙ 1.5^^^^2^^^^(^^^^) isthermodynamically and / or kinetically favored over the dehydrated form ^^^^2^^^^^^^^3(^^^^). In some 6sf-625386234037-20002.40 variations, during step 3: use of steam as the carrier gas to ensure high moisture content, CO2 as the carrier gas to ensure low moisture content, or a combination of the two to control the moisture in the reactor during the regeneration reaction is utilized. In some variations, during step 3: the carrier gas is a gas stream supplied into the reactor of interest during step 3 to assist in removal of the released CO2 from the regeneration reaction. In some variations, during step 3: the carrier gas is a gas stream supplied into the reactor of interest during step 3 to assist in heat transfer. In some variations, during step 4: use of a gas at an elevated pressure (e.g. compressed air) to remove excess moisture in the reactor (both gaseous and condensate, if applicable) is utilized. In some variations, enough moisture shall be retained such that duringstep 4-5, ^^^^2^^^^^^^^3 ∙ 1.5^^^^2^^^^(^^^^) remains a hydrate. In some variations, during step 5: an internalcooling loop where a cooler (electrical or heat exchanger), an in-line fan and the reactor of interest are connected in series to ramp down the temperature of the reactor without introducing external gases is utilized. In some variations, during step 5: condensate formed in the loop is removed through mechanical method(s). In some variations, during step 5: an external cooling method where optionally a cooler (electrical or heat exchanger), a fan and the reactor of interest are connected in series to ramp down the temperature of the reactor by introducing external gases is utilized.

[0033] In some aspects, provided is an engineering process that realizes the promise of low energy consumption for the hydrated potassium carbonate carbon capture. In some embodiments, for example, given the low heat capacities of the reagents in the reaction, the sensible heat is approximately 0.2 GJ / tonne-CO2, bringing the total thermal energy requirement for carbon capture using this technology to 1.2 GJ / tonne-CO2 prior to the application of heat recovery, a 66% reduction compared to the best alternative described herein.

[0034] In some aspects, provided herein is a new method of manufacturing solid packing material via mixing-drying-crushing-sieving. In some embodiments, the method of manufacturing is a scalable and low-cost method flexible to incorporate a wide range of solid and liquid ingredients. In some aspects, provided herein is a reactor surface treatment or modification to create a non-sticky surface, such that the reactor can be packed with sticky but otherwise stable and high-performance packing (i.e., sorbent) with easy maintenance.

[0035] In some aspects, provided herein is a method to manufacture reactor packing (i.e., sorbent) via mixing-heating-crushing-sieving. In some aspects, provided herein is a reactor inner wall surface treatment or modification to prevent packing sticking to the reactor walls during operation. In some embodiments, a method of manufacturing sorbent comprising mixing 7sf-625386234037-20002.40 raw materials (and solvents) in powder or liquid forms in a mixer. In some embodiments, the mixture is then dried in a dryer to remove extra solvent and to harden. In some embodiments, the hardened material is subsequently crushed to small pieces, and then sieved to produce reactor packing within a specified size range. In some aspects, provided herein is an inner wall surface treatment or modification. In some embodiments, the inner wall surface treatment or modification can be applied to reactors packed with the sorbent manufactured using a method described herein, or any other solid material that is or can become sticky during operation. In some embodiments, the treatment involves a Teflon, silicone, or similar non-sticky coating applicable to the sticky ingredient(s) in the packing (i.e., sorbent) on the inner surface of the reactor. In some embodiments, the modification involves a physical layer of Teflon, silicone or similar material installed on the inner surface of the reactor such that it separates the bare reactor wall material and the packing. In some embodiments, the method for packing manufacturing is simple, scalable, and low cost at scale. In some embodiments, the method for packing manufacturing is flexible to include a variety of solid and liquid ingredients necessary to achieve desired performance and stability. In some embodiments, small packing pieces produced in the crushing process can be sent back to the mixer and recycled. In some embodiments, the non-sticky reactor surface treatment or modification allows the use of otherwise stable and performing packing in a packed bed reactor. In some embodiments, the application of the surface treatment or modification can be done at the factory of the reactor system, without changing existing packing or unpacking methods. In some embodiments, the existing operations and procedures are also unaffected. In some embodiments, the process can be used for carbon capture. For example, in some embodiments, carbon capture sorbent material can be manufactured via the mixing-drying-crushing-sieving method, and sticky but otherwise high-performance sorbent can be packed in a surface-treated reactor as described herein.

[0036] Unless contraindicated or noted otherwise, in these descriptions and throughout this specification, the terms “a” and “an” mean one or more, the term “or” means and / or. The term “and / or” as used herein a phrase such as “A and / or B” is intended to include both A and B; A or B; A alone; and B alone, and a phrase such as “A, B, and / or C” is intended to encompass each of the following: A, B, and C; A, B, or C; A or C; A or B; B or C; A and C; A and B; B and C; A alone; B alone; and C alone.

[0037] Reference to “about” a value or parameter herein includes (and describes) variations that are directed to that value or parameter per se. For example, description referring to “about X” includes description of “X”. 8sf-625386234037-20002.40

[0038] In some variations, the terms “wt%”, “%wt”, “weight percent”, “percent by weight”, “% by weight”, and equivalent are used herein interchangeably to refer to a weight percent, or percent by weight, of a component. For example, weight percent may be used to characterize a relative amount of a component in a solid mixture, in a fluid mixture, or in a fluid stream, for example. In some variations, weight percent of a component may be characterized more particularly with respect to one or more certain other components. Unless contraindicated, the reference to “wt%”, “%wt”, “weight percent”, “percent by weight”, “% by weight” is on a dry basis. For example, in some variations, 50 wt% of a component refers to the weight of the component relative to the total weight of the sorbent (not including solvent).

[0039] In some variations, the term “average granule size” refers to an average of a size characteristic of a set of granules, such as granules in a packed bed, granules in a fluidized bed, granules in a gaseous stream or granules in a slurry. In some variations, the term “size characteristic” refers to a property, or set of properties, of a granule that directly or indirectly relates to a size attribute. According to some embodiments, a size characteristic corresponds to an empirically-derived size characteristic of a granule(s) being detected, such as a size characteristic based on, determined by, or corresponding to data from any of the probes disclosed herein or other art-known probes capable of detecting granules (e.g., a size characteristic corresponding to a spherical granule exhibiting similar or substantially same properties, such as aerodynamic, hydrodynamic, optical, and / or electrical properties, as the granule(s) being detected). According to some aspects, a size characteristic corresponds to a physical dimension, such as a cross-sectional size (e.g., length, width, thickness, diameter).

[0040] In some variations of the foregoing, a gas or gaseous stream may comprise “condensed water” or “liquid water” carried by, aerosolized in, and / or suspended in the gas or gaseous stream. As used herein, in such context, these terms “condensed water” and “liquid water” are equivalent and used interchangeably. In some embodiments, for example, condensed water in a gas or gaseous stream is in the form of liquid water droplets carried by, aerosolized in, and / or suspended in the gas or gaseous stream. In some variations, a gaseous stream may be characterized as having a particular weight fraction or weight percent (wt%) of condensed water, which is a percent corresponding to the weight fraction of H2O / (H2O+CO2+(other gaseous components and suspended / aerosolized components in the gas stream)).

[0041] The terms “fluidized bed reactor” and “fixed bed reactor” are intended to be consistent with the terms as known by those skilled in the art, such as chemical engineering. 9sf-625386234037-20002.40 Sorbent Compositions

[0042] In some aspects, provided herein are sorbent compositions, also referred to herein as “sorbents” and “sorbent material”, comprising at least one moisture control additive. In some embodiments, the sorbent compositions disclosed herein are solid sorbents. In some embodiments, the moisture control additive stabilizes the sorbent composition under moist and / or humid conditions, such as flue gas. In some embodiments, the sorbent compositions described herein are capable of absorbing, chemisorbing, physisorbing, binding, or otherwise capturing CO2. In some variations, the CO2 is present in flue gas or off gas from mining, drilling, manufacturing, and the like.

[0043] In some embodiments, the sorbent composition is deliquescent. In some embodiments, the sorbent composition comprises: an active component for CO2 chemisorption and at least one moisture control additive that serves as a stabilizer. In some embodiments, the sorbent composition comprises: an active component for CO2 chemisorption, a moisture control additive that serves as a stabilizer, and a support material. The components of the sorbent compositions provided herein are described in further detail below. Active Component for CO2 Chemisorption

[0044] In some embodiments of the sorbent compositions provided herein, the active component for CO2 chemisorption is one or more metal carbonate salts (i.e., metal carbonates). In some embodiments, the one or more metal carbonates adsorbs CO2. In some embodiments, the one or more metal carbonates is an alkaline carbonate or an alkaline earth carbonate. In some embodiments, the one or more metal carbonates is potassium carbonate (i.e., K2CO3), sodium carbonate (i.e., Na2CO3), lithium carbonate (i.e., Li2CO3), calcium carbonate (i.e., CaCO3), magnesium carbonate (i.e., MgCO3), rubidium carbonate (i.e., Rb2CO3), cesium carbonate (i.e, Cs2CO3), or any combination of the foregoing. In some embodiments, the metal carbonate is K2CO3, Na2CO3, CaCO3, MgCO3, or any combination thereof. In some embodiments, the metal carbonate is K2CO3, Na2CO3, or any combination thereof. In certain embodiments, the metal carbonate is K2CO3. In certain embodiments, the metal carbonate is Na2CO3. In certain embodiments, the metal carbonate is Li2CO3. In certain embodiments, the metal carbonate is CaCO3. In certain embodiments, the metal carbonate is MgCO3. In certain embodiments, the metal carbonate is Rb2CO3. In certain embodiments, the metal carbonate is Cs2CO3. 10sf-625386234037-20002.40

[0045] In some variations, it should also be understood that certain components suitable as an active component for CO2 chemisorption may serve other functions within the composition. For instance, some of the components listed above may serve as a filler, e.g., CaCO3.

[0046] In some variations of the foregoing, the metal carbonate is deliquescent (i.e., absorbs water from the air and dissolves above a certain relative humidity (RH)). In certain variations, the deliquescent metal carbonate is K2CO3 and its deliquescent point (i.e., the RH at which K2CO3 mechanically decomposes into a solution) is about 44% RH or greater. In certain variations, the deliquescent metal carbonate is Na2CO3 and its deliquescent point is about 67% RH or greater. In some embodiments, the deliquescent metal carbonate is K2CO3, Na2CO3, Rb2CO3, CsCO3, or a combination thereof. In certain embodiments, the deliquescent metal carbonate is K2CO3.

[0047] In some embodiments, the active component for CO2 chemisorption is stabilized by a moisture control additive of the sorbent composition, as described further herein. For example, in some embodiments, the sorbent composition comprises K2CO3, Na2CO3, Rb2CO3, CsCO3, or a combination thereof, which is stabilized by a moisture control additive of the composition during use of the sorbent composition for carbon capture.

[0048] In some embodiments, the active component for CO2 chemisorption is in the form of a hydrate as described herein when used for carbon capture. In some embodiments, the active component for CO2 chemisorption that is in the form of a hydrate is K2CO3, Na2CO3, Li2CO3, MgCO3, Rb2CO3, CsCO3, or any combination thereof. Moisture Control Additives

[0049] In some aspects, provided herein are sorbent compositions comprising at least one moisture control additive that serves as a stabilizer of at least one active component of the sorbent composition. In some variations, the moisture control additive increases the stability of the sorbent composition in moist and / or humid environments. In certain variations, at least one metal carbonate of the sorbent composition is deliquescent, and the moist and / or humid environment is an environment in which the moisture content (i.e., the relative humidity (RH)) is greater than that of the deliquescent point of the metal carbonate sorbent composition. For example, in some variations, the inclusion of one or more moisture control additives results in a sorbent composition with increased moisture resistance. In some embodiments, the moisture- resistant sorbent can withstand the high and fluctuating humidity condition of flue gases in contact with the sorbent composition when used for carbon capture. Such allows a longer 11sf-625386234037-20002.40 lifetime of the sorbent, easier removal and replacement of the sorbent at the end of its lifetime, easier maintenance of the process equipment, and more steady operation of the carbon capture process. It also eliminates the need for certain flue gas conditioning such as moisture removal prior to contacting the sorbent.

[0050] In some variations of the foregoing, the at least one moisture control additive stabilizes the sorbent composition by facilitating the formation and maintenance of a hydrate form of the metal carbonate of the sorbent composition, as further described herein. Without being bound by theory, in some embodiments, the one or more moisture control additives facilitate the formation and maintenance of a hydrate form of a metal carbonate of the sorbent composition in humid environments by modulating the relative humidity of the local environment of the sorbent composition (e.g., via adsorbing or absorbing water), which stabilizes the mechanical structure of the sorbent composition, thereby retaining its chemical activity for carbon capture. Without being bound by theory, the mechanical structure of the sorbent is stabilized by maintaining the relative humidity of the local environment of the sorbent composition so that the one or more metal carbonates of the sorbent composition is preferentially in the form of a hydrate in the solid phase. In some embodiments, the moisture control additive is hygroscopic.

[0051] In some variations, the moisture control additive chemically (e.g., chemisorption) and / or physically (e.g., physisorption) uptakes gaseous or liquid water in the local environment (i.e., near the sorbent composition) and maintains the relative humidity of the local environment of the sorbent composition to below the deliquescent point of the sorbent composition. In some variations, a hydrate form of the moisture control additive results from the absorption of gaseous or liquid water from the local environment by the moisture control additive. For example, in certain variations, the moisture control additive is CaCl2 and forms a hydrate in the form of CaCl2·2H2O upon absorption of gaseous or liquid water from the local environment of the sorbent composition. In other variations, the moisture control additive is a zeolite which adsorbs gaseous or liquid water from the local environment.

[0052] In some variations of the foregoing, the moisture control additive enhances the mechanical stability of the sorbent composition. For example, in some variations, CaCl2 increases the mechanical strength of the sorbent composition by absorbing gaseous or liquid water and forming crystals. In some variations, the increase in mechanical stability of the sorbent composition prevents the sorbent composition from decomposing, aggregating, fusing, or any combination thereof when used for carbon capture as described herein. 12sf-625386234037-20002.40

[0053] In some embodiments, the moisture control additive prevents dissolution or softening of the sorbent composition in humid environments by absorbing moisture in the local environment of the sorbent composition and maintaining the relative humidity of the local environment of the sorbent composition below the deliquescence point of the sorbent. In some embodiments, the moisture control additive prevents dissolution or softening of the sorbent composition in humid environments by absorbing moisture in the local environment of the sorbent composition and maintaining the relative humidity of the local environment of the sorbent composition below the deliquescence point of the active component for CO2 chemisorption of the sorbent composition. In certain embodiments, the moisture control additive of the sorbent compositions described herein helps maintain between about 5% relative humidity to a relative humidity that is less than that of the deliquescent point of the sorbent composition. In certain embodiments, the moisture control additive of the sorbent compositions described herein helps maintain between about 5% relative humidity to a relative humidity that is less than that of the deliquescent point of the active component for CO2 chemisorption of the sorbent composition. For example, for sorbent compositions comprising K2CO3, the moisture control additive uptakes moisture as described herein between about 5% RH and about 44% RH (e.g., the deliquescent point of K2CO3) at 60 °C.

[0054] In some embodiments, the one or more moisture control additives chemically or physically uptake gaseous or liquid water above target humidity in order to control the relative humidity of the local environment of the sorbent composition. In some embodiments, the one or more moisture control additives modulate the local chemical activity of water by maintaining the relative humidity of the local environment of the metal carbonate at a level that is high enough to facilitate and maintain the formation of the hydrate form of the metal carbonate but below the deliquescent point of the sorbent composition, thereby stabilizing the mechanical structure of the sorbent composition while retaining its chemical activity for carbon capture. In some embodiments, the one or more moisture control additives reduces the activity of water which increases the stability of the sorbent composition. In some embodiments, the moisture control additive prevents dissolution or softening of the sorbent composition in humid environments.

[0055] In some embodiments, the one or more moisture control additives uptakes moisture at near 0% relative humidity. In some embodiments, the one or more moisture control additives that uptake moisture at near 0% relative humidity are calcium chloride, zeolite, silica gel (i.e., SiO2), and potassium chloride (i.e., KCl). In certain embodiments, the zeolite is 13X zeolite. 13sf-625386234037-20002.40

[0056] In some embodiments, the moisture control additive comprises a material that uptakes moisture at an elevated relative humidity. In some embodiments, the relative humidity is lower than the deliquescence point of the sorbent composition. In some embodiments, the relative humidity is lower than the deliquescence point of the metal carbonate. In some embodiments, the moisture control additives are the most effective when incoming gas stream has a high relative humidity relative to the deliquescence point of the primary active ingredient (i.e., active component for CO2 chemisorption) of the sorbent material under the design reaction conditions. In some embodiments, the stabilizing effect of the one or more moisture control additives is highest when the environment surrounding the sorbent composition has a high relative humidity as compared to the deliquescence point of the primary active ingredient (i.e., active component for CO2 chemisorption) of the sorbent material under the conditions used for carbon capture as described herein (e.g., K2CO3 has a deliquescence point of 44%RH in an environment at 80%RH). In some embodiments, the moisture control additive that uptakes moisture at elevated relative humidity is magnesium aluminosilicate.

[0057] In some embodiments, the moisture control additive comprises a halide salt. In some embodiments, the halide salt is a chloride salt. In some embodiments, the chloride salt comprises a calcium chloride salt, a potassium chloride salt, or a combination thereof. In some embodiments, the calcium chloride salt is calcium chloride (i.e., CaCl2). In some embodiments, the potassium chloride salt is potassium chloride (i.e., KCl). In some embodiments, the moisture control additive comprises halide salts that are known to adsorb and / or absorb water. In some variations, the deliquescent point of CaCl2 is about 30% RH at room temperature.

[0058] In some embodiments, the moisture control additive comprises a calcium salt. In some variations, the moisture control additive comprises calcium salts that are known to adsorb and / or absorb water.

[0059] In some embodiments, the moisture control additive comprises an acetate salt. In some embodiments, the acetate salt comprises sodium acetate, potassium acetate, or any combination thereof. In some variations, the moisture control additive comprises acetate salts that are known to adsorb and / or absorb water. In some embodiments, the acetate salt is sodium acetate (i.e., CH3COONa). In some embodiments, the sodium salt is potassium acetate (i.e. CH3COOK).

[0060] In some embodiments, the moisture control additive comprises acetate salts that are known to adsorb or absorb water. In some variations, the deliquescent point of sodium acetate 14sf-625386234037-20002.40 (i.e., CH3COONa) is about 40% RH at room temperature. In some variations, the deliquescent point of potassium acetate (i.e., CH3COOK) is about 20% RH at room temperature.

[0061] In some embodiments, the moisture control additive comprises activated carbon.

[0062] In some embodiments, the one or more moisture control additives of the sorbent compositions comprises a halide salt, an acetate salt, silica gel, celite, aluminosilicate, activated carbon, or any combination thereof. In some embodiments, the one or more moisture control additives of the sorbent compositions comprises CaCl2, silica gel, celite, aluminosilicate, or any combination thereof. In some embodiments, the aluminosilicate is magnesium aluminosilicate, bentonite, zeolite, or any combination thereof. In some embodiments, the zeolite is clinoptilolite or 13x zeolite, or a combination thereof. In certain variations, the aluminosilicate is magnesium aluminosilicate. In some embodiments, the aluminosilicate is bentonite. In some embodiments, the aluminosilicate is zeolite. In some embodiments, the zeolite is clinoptilolite. In some embodiments, the zeolite is 13x zeolite. In some embodiments, the one or more moisture control additives of the sorbent compositions comprises CaCl2, silica gel, celite, aluminosilicate, magnesium aluminosilicate, bentonite, zeolite, clinoptilolite, 13x zeolite, or any combination thereof.

[0063] In some variations of the foregoing, the inclusion of one or more moisture control additives eliminates the need to for certain flue gas conditioning such as moisture removal prior to contacting the flue gas with the sorbent composition during carbon capture.

[0064] In some embodiments, the one or more moisture control additives adsorb CO2 (e.g., physisorption) during carbon capture and increase the CO2 sorption capacity and kinetics of the sorbent composition. In some embodiments, the one or more moisture control additives that adsorb CO2 is zeolite. In some embodiments, the zeolite is 13x zeolite, clinoptilolite, celite, or any combination thereof. In some embodiments, the zeolite is 13x zeolite. In some embodiments, the zeolite is clinoptilolite. In some embodiments, the zeolite is celite.

[0065] In some variations, the inclusion of one or more moisture control additives in the sorbent composition facilitates one or more of (i) a longer lifetime of the sorbent composition; (ii) easier removal and replacement of the sorbent composition at the end of its lifetime; (iii) easier maintenance of the process equipment; (iv) and more steady operation of the carbon capture process. For example, in some variations of the foregoing sorbent compositions, the inclusion of a moisture control additive as described herein prevents sorbent from becoming sticky and sticking to the reactor wall after one or more carbon capture cycles, which allows for 15sf-625386234037-20002.40 easier removal and replacement of the sorbent composition from a reactor after use for carbon capture. In some variations, the moisture control additive helps maintain the mechanical structure of the sorbent composition and stable gas flow rates during the absorption phase of carbon capture, as described herein. In some embodiments, the moisture control additive prevents the deliquescence of the sorbent composition, and thereby avoids recrystallization and aggregation of the sorbent composition during carbon capture as described herein and prevents the sorbent composition from sticking to reactor walls after one or more carbon capture cycle, as described herein.

[0066] In some embodiments, the addition of moisture control additives to sorbent compositions as described herein may hinder the carbon capture performance of the sorbent. Chemical strategies such as layered sorbent, addition of promoters to the sorbent as well as engineering strategies such as preconditioning of the reactor environment at a specific temperature, pressure and humidity may be deployed to compensate for the reduced capture performance, as further described herein.

[0067] In some variations, the sorbents provided herein are arranged as layered sorbents. Such layered sorbents may provide sufficient physical distance between the carbonate hydrate and the moisture control additive such that considerable amount of the carbonate hydrate is not in the immediate vicinity of the moisture additive and have a higher relative humidity in the local environment to facilitate the CO2 absorption reaction.

[0068] In some embodiments, a promoter may be added to the sorbent. In some variations, the sorbent is a chemical that accelerates CO2 uptake by forming a reactive intermediate with CO2 that can subsequently react with carbonate to form bicarbonate. In some embodiments, a promoter has an exposed lone pair of electrons acting as a Lewis base to react with CO2. In some embodiments, the addition of a promoter increases the CO2 absorption kinetics of carbonate sorbents. In some embodiments, the sorbent composition comprises one or more promoters.

[0069] It shout be understood that in some variations, certain moisture control additives may also act as a support material as described herein. For example, in some embodiments, the moisture control additive and support material of the sorbent composition is activated carbon. In some embodiments, the moisture control additive and the support material of the sorbent compositions described herein are the same material. Support Material 16sf-625386234037-20002.40

[0070] In some aspects, provided are sorbent compositions comprising one or more support materials. In some embodiments, the support material has a high specific surface area. In some embodiments, the support material has a high porosity. In some embodiments, the support material increases the specific surface area of the sorbent composition. In some embodiments, the support material increases the density of the sorbent composition. In some embodiments, the one or more support materials is aluminum oxide (i.e., Al2O3), cerium oxide (i.e., CeO2), activated carbon, pseudoboehmite, or any combination thereof. In some embodiments, Al2O3 is activated Al2O3. In some embodiments, the support material is Al2O3, CeO2, pseudoboehmite, or a combination thereof.

[0071] In some embodiments, for example, the density of the sorbent composition increases with the inclusion of Al2O3 as a support material. Generally, increasing the density of the sorbent composition increases the amount of active component of the sorbent composition that is available to react with CO2 during carbon capture, thereby increasing the CO2 capture capacity and kinetics per volume of the sorbent.

[0072] It shout be understood that in some variations, certain support materials may also act as a moisture control additive as described herein. For example, in some embodiments, the moisture control additive and support material of the sorbent composition is activated carbon. In some embodiments, the moisture control additive and the support material of the sorbent compositions described herein are the same material. Formation of Stable Carbonate Hydrates

[0073] The sorbent compositions provided herein may be used for carbon capture, as described herein. In some variations, the one or more moisture control additives of the sorbent compositions of the foregoing facilitates the formation of a stable hydrate form of the one or more metal carbonates (i.e., active component for CO2 chemisorption) under near absorption conditions useful for carbon capture. For example, in some embodiments, the metal carbonate of sorbent compositions described herein comprising a moisture control additive forms a stable hydrate under near absorption conditions according equation E-1: stable MxCO3∙ yH2O at 0-90 °C, < 20% volume H2O (E-1) where subscript x and subscript y are integers or fractions. The stoichiometry of stable hydrates of the metal carbonates described herein can be determined using methods known in the art. For example, in certain variations, x is between about 1 and about 2, y is between about 1 and 17sf-625386234037-20002.40 about 3, or any combination thereof. In some variations of the sorbent compositions described herein, K2CO3 is the metal carbonate, and subscript x and y in equation E-1 are 2 and 1.5, respectively.

[0074] In certain variations, the active component for CO2 chemisorption of the sorbent composition is K2CO3, and the one or more moisture control additives of the sorbent composition facilitates the formation of a stable hydrate of the metal carbonate at atmospheric pressure according to equation E-2: stable K2CO3∙ 1.5H2O at 60 °C, 10% volume H2O at atmospheric pressure (E-2).

[0075] In some embodiments, the stable hydrate of the metal carbonate described herein reacts with CO2 according to equation E-3: ^^^^xx^^^^^^^^3 ∙ yy1^^^^2^^^^ (^^^^) + ^^^^^^^^2(g) ↔ x1M(^^^^^^^^^^^^3)^^^^(s) + b^^^^2^^^^(^^^^) (E-3)where subscript xx, subscript yy, subscript a, and subscript b are integers or fractions. In certain variations, subscript xx is between 1 and about 2, subscript yy is between about 1.5 and about 3, subscript a is between about 1 and about 2, subscript b is between 0 and about 2, or any combination thereof.

[0076] In some embodiments, the formation of stable hydrate of the metal carbonate of the sorbent composition reduces the energy requirements for regenerating the sorbent composition when used for carbon capture. For example, a sorbent composition comprising K2CO3 and a moisture control additive as described herein which has undergone one or more carbon capture cycles, as described herein, and is regenerated to the stable carbonate hydrate form, as described herein, according to equation E-4: 2^^^^^^^^^^^^^^^^3(^^^^) + 0.5^^^^2^^^^ (^^^^) → ^^^^2^^^^^^^^3 ∙ 1.5^^^^2^^^^(^^^^) + ^^^^^^^^2(^^^^) (E-4)which has a heat of reaction of 40 kJ / mol, whereas the heat of reaction wherein the stable carbonate hydrate form of sorbent is not utilized is 140 kJ / mol according to the following equation E-5: 2^^^^^^^^^^^^^^^^3 → ^^^^2^^^^^^^^3(s) + ^^^^2^^^^(^^^^) + ^^^^^^^^2(^^^^) (E-5).

[0077] Thus, in some embodiments, the energy required to regenerate sorbent compositions described herein during carbon capture is reduced as compared to methods used in the art. Sorbent Composition Component Amounts and Ratios 18sf-625386234037-20002.40

[0078] In some aspects of the foregoing, the sorbent composition comprises about 30 wt% to about 80 wt% of one or more active components for CO2 chemisorption, about 5 wt% to about 60 wt% of one or more moisture control additives, and about 0 wt% to about 60 wt% of support material. Weight Percentages of Components

[0079] In some embodiments, the sorbent composition comprises about 40 wt% to about 80 wt% of one or more active components for CO2 chemisorption.

[0080] In other embodiments, the sorbent compositions described herein comprise about 40 wt% to about 80 wt% of Li2CO3, K2CO3, NaCO3, MgCO3, CaCO3, Rb2CO3, CsCO3, or any combination thereof. In some embodiments, the sorbent composition comprises between about 40 wt% to about 80 wt% of K2CO3, Na2CO3, CaCO3, or any combination thereof. In some embodiments, the sorbent composition comprises between about 40 wt% to about 80 wt% of K2CO3, CaCO3, or any combination thereof. In some embodiments, the sorbent composition comprises about 40 wt% to about 80 wt% of K2CO3. In some embodiments, the sorbent composition comprises between about 40 wt% to about 80 wt% of Na2CO3. In some embodiments, the sorbent composition comprises about 40 wt% to about 80 wt% of CaCO3.

[0081] In some embodiments, the sorbent composition comprises between about 40 wt% to about 80 wt% of K2CO3, Na2CO3, or any combination thereof. In certain embodiments, the sorbent composition comprises about 40 wt% to about 80 wt%, 45 wt% to about 75 wt%, about 50 wt% to about 70 wt%, or about 55 wt% to about 65 wt% K2CO3, Na2CO3, or any combination thereof. In certain embodiments, the sorbent composition comprises about 40 wt%, about 45 wt%, about 50 wt%, about 55 wt%, about 60 wt%, about 65 wt%, about 70 wt%, about 75 wt%, or about 80 wt% of K2CO3, Na2CO3, or any combination thereof.

[0082] In some embodiments, the sorbent composition comprises between about 40 wt% to about 80 wt% of K2CO3, CaCO3, or any combination thereof. In certain embodiments, the sorbent composition comprises about 40 wt% to about 80 wt%, 45 wt% to about 75 wt%, about 50 wt% to about 70 wt%, or about 55 wt% to about 65 wt% K2CO3, CaCO3, or any combination thereof. In certain embodiments, the sorbent composition comprises about 40 wt%, about 45 wt%, about 50 wt%, about 55 wt%, about 60 wt%, about 65 wt%, about 70 wt%, about 75 wt%, or about 80 wt% of K2CO3, Ca2CO3, or any combination thereof. In certain embodiments, the sorbent composition comprises about 55 wt% K2CO3 and about 10 wt% CaCO3. 19sf-625386234037-20002.40

[0083] In some embodiments, the sorbent composition comprises about 40 wt% to about 80 wt%, 45 wt% to about 75 wt%, about 50 wt% to about 70 wt%, or about 55 wt% to about 65 wt% K2CO3. In some embodiments, the sorbent composition comprises about 40 wt% to about 80 wt%, about 45 wt% to about 60 wt%, about 45 wt% to about 75 wt%, about 50 wt% to about 70 wt%, or about 55 wt% to about 65 wt% K2CO3. In certain embodiments, the sorbent composition comprises about 40 wt%, about 45 wt%, about 50 wt%, about 55 wt%, about 60 wt%, about 65 wt%, about 70 wt%, about 75 wt%, or about 80 wt% K2CO3. In certain embodiments, the sorbent composition comprises about 50 wt% to about 60 wt% K2CO3, or about 50 wt%, about 51 wt%, about 52 wt%, about 53 wt%, about 54 wt%, about 55 wt%, about 56 wt%, about 57 wt%, about 58 wt%, about 59 wt%, or about 60 wt% K2CO3. In some embodiments, the sorbent composition comprises about 55 wt% K2CO3.

[0084] In some embodiments, the sorbent composition comprises about 5 wt% to about 20 wt%, about 10 wt% to about 20 wt%, about 15 wt% to about 20 wt%, about 5 wt% to about 15 wt%, or about 5 wt% to about 10 wt% CaCO3.

[0085] In some embodiments, the sorbent composition comprises about 5 wt% to about 60 wt% of one or more moisture control additives. For example, in some variations, the sorbent compositions described herein comprise about 5 wt% to about 60 wt% of CaCl2, zeolite, silica gel, bentonite, celite, aluminosilicate, clinoptilolite, zeolite 13x, or any combination thereof.

[0086] In some embodiments, the sorbent composition comprises about 5 wt% to about 60 wt% of CaCl2, celite, zeolite, or any combination thereof. In some embodiments, the sorbent composition comprises about 5 wt% to about 60 wt%, about 10 wt% to about 55 wt%, about 15 wt% to about 50 wt%, about 20 wt% to about 45 wt%, about 25 wt% to about 40 wt%, or about 30 wt% to about 35 wt% of CaCl2, celite, zeolite, or any combination thereof. In some embodiments, zeolite is 13x.

[0087] In some embodiments, the sorbent composition comprises about 5 wt% to about 60 wt% of CaCl2. In some embodiments, the sorbent composition comprises about 5 wt% to about 35 wt%, about 5 wt% to about 30 wt%, about 5 wt% to about 20 wt%, about 5 wt% to about 15 wt%, about 5 wt% to about 10 wt%, or about 10 wt% to about 15 wt% of CaCl2. In certain embodiments, the sorbent composition comprises about 5 wt%, about 10 wt%, about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, or about 35 wt% of CaCl2. In certain embodiments, the sorbent composition comprises about 15 wt% CaCl2. In certain 20sf-625386234037-20002.40 embodiments, the sorbent composition comprises about 10 wt% CaCl2. In certain embodiments, the sorbent composition comprises about 5 wt% CaCl2.

[0088] In some embodiments, the sorbent composition comprises about 5 wt% to about 60 wt% of zeolite. In certain embodiments, the sorbent composition comprises about 5 wt% to about 60 wt%, about 5 wt% to about 40 wt%, about 5 wt% to about 25 wt%, about 5 wt% to about 20 wt%, about 5 wt% to about 15 wt%, about 5 wt% to about 10 wt%, about 10 wt% to about 50 wt%, about 10 wt% to about 40 wt%, about 10 wt% to about 30 wt%, about 10 wt% to about 20 wt%, about 10 wt% to about 15 wt%, about 20 wt% to about 60 wt%, about 20 wt% to about 50 wt%, about 20 wt% to about 40 wt%, about 30 wt% to about 60 wt%, about 30 wt% to about 50 wt%, or about 30 wt% to about 40 wt% zeolite. In certain embodiments, the sorbent composition comprises about 5 wt%, about 10 wt%, about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, or about 35 wt% of zeolite. In certain variations of the foregoing, the zeolite is 13x zeolite.

[0089] In some embodiments, the sorbent composition comprises about 5 wt% to about 60 wt% of silica gel. In some embodiments, the sorbent composition comprises about 5 wt% to about 60 wt% of bentonite. In some embodiments, the sorbent composition comprises about 5 wt% to about 60 wt% of celite. In some embodiments, the sorbent composition comprises about 5 wt% to about 60 wt% of aluminosilicate. In some embodiments, the sorbent composition comprises about 5 wt% to about 60 wt% of clinoptilolite.

[0090] In some embodiments, the sorbent composition comprises about 0 wt% to about 60 wt% of one or more support materials. For example, in some variations, the sorbent compositions described herein comprise about 0 wt% to about 60 wt% of Al2O3, CeO2, pseudoboehmite, or any combination thereof. In some embodiments, the sorbent composition comprises about 5 wt% to about 60 wt%, about 10 wt% to about 55 wt%, about 15 wt% to about 50 wt%, about 20 wt% to about 45 wt%, about 25 wt% to about 40 wt%, or about 30 wt% to about 35 wt% of Al2O3, CeO2, pseudoboehmite, or any combination thereof.

[0091] In some embodiments, the sorbent composition comprises about 0 wt% to about 60 wt% of Al2O3, CeO2, pseudoboehmite, or any combination thereof. In some embodiments, the sorbent composition comprises about 10 wt% to about 60 wt%, about 10 wt% to about 50 wt%, 10 wt% to about 40 wt%, 10 wt% to about 20 wt%, about 20 wt% to about 60 wt%, about 20 wt% to about 50 wt%, about 20 wt% to about 40 wt%, about 20 wt% to about 30 wt%, about 30 wt% to about 60 wt%, about 30 wt% to about 50 wt%, about 30 wt% to about 40 wt%, 21sf-625386234037-20002.40 about 5 wt% to about 15 wt%, about 15 wt% to about 25 wt%, about 25 wt% to about 45 wt%, about 45 wt% to about 55 wt%, or about 25 wt% to about 55 wt% Al2O3, CeO2, pseudoboehmite, or any combination thereo. In certain embodiments, the sorbent composition comprises about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, about 35 wt%, about 40 wt%, or about 45 wt% of Al2O3, CeO2, pseudoboehmite, or any combination thereof.

[0092] In some embodiments, the sorbent composition comprises about 0 wt% to about 60 wt% of Al2O3. In some embodiments, the sorbent composition comprises about 10 wt% to about 60 wt%, about 10 wt% to about 50 wt%, 10 wt% to about 40 wt%, 10 wt% to about 20 wt%, about 20 wt% to about 60 wt%, about 20 wt% to about 50 wt%, about 20 wt% to about 40 wt%, about 20 wt% to about 30 wt%, about 30 wt% to about 60 wt%, about 30 wt% to about 50 wt%, about 30 wt% to about 40 wt%, about 5 wt% to about 15 wt%, about 15 wt% to about 25 wt%, about 25 wt% to about 45 wt%, about 45 wt% to about 55 wt%, or about 25 wt% to about 55 wt% Al2O3. In certain embodiments, the sorbent composition comprises about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, about 35 wt%, about 40 wt%, or about 45 wt% of Al2O3. In certain embodiments, the sorbent composition comprises about 35 wt% Al2O3. In certain embodiments, the sorbent composition comprises about 30 wt% Al2O3. In certain embodiments, the sorbent composition comprises about 25 wt% Al2O3. In certain embodiments, the sorbent composition comprises about 20 wt% Al2O3. In certain embodiments, the sorbent composition comprises about 15 wt% Al2O3.

[0093] In some variations of the sorbent compositions described herein, the sorbent composition comprises about 40 wt% to about 80 wt% K2CO3, about 5 wt% to about 20 wt% CaCl2, and about 5 wt% to about 40 wt% Al2O3. In certain variations, the sorbent composition comprises about 45 wt% to about 60 wt% K2CO3, about 10 wt% to about 20 wt% CaCl2, and about 15 wt% to about 25 wt% Al2O3. In certain variations, the sorbent composition comprises about 50 wt% K2CO3, about 15 wt% CaCl2, and about 20 wt% Al2O3. In certain variations, the sorbent composition comprises about 55 wt% K2CO3, about 15 wt% CaCl2, and about 15 wt% Al2O3. In certain variations, the sorbent composition comprises about 50 wt% K2CO3, about 13 wt% CaCl2, and about 25 wt% Al2O3. In certain variations, the sorbent composition comprises about 50 wt% K2CO3, about 5 wt% CaCl2, about 15 wt% 13x zeolite, and about 30 wt% Al2O3.

[0094] In other variations, the sorbent composition comprises about 40 wt% to about 80 wt% K2CO3, about 5 wt% to about 20 wt% CaCl2, about 5 wt% to about 40 wt% Al2O3, and about 10 wt% to 20 wt% CaCO3. In certain variations, the sorbent composition comprises 22sf-625386234037-20002.40 about 50 wt% K2CO3, about 15 wt% CaCl2, about 20 wt% Al2O3, and about 15 wt% CaCO3. In certain variations, the sorbent composition comprises about 55 wt% K2CO3, about 15 wt% CaCl2, about 15 wt% Al2O3, and about 15 wt% CaCO3. In certain variations, the sorbent composition comprises about 50 wt% K2CO3, about 13 wt% CaCl2, about 25 wt% Al2O3, and about 12 wt% CaCO3.

[0095] In other variations, the sorbent composition comprises about 52 wt% K2CO3, about 16 wt% CaCO3, about 25 wt% Al2O3, and about 8 wt% CaCl2. In other variations, the sorbent composition comprises about 55 wt% K2CO3, about 10 wt% CaCO3, about 25 wt% celite, and about 10 wt% CaCl2. In other variations, the sorbent composition comprises about 55 wt% K2CO3, about 10 wt% CaCO3, about 25 wt% Al2O3, and about 10 wt% CaCl2. In other variations, the sorbent composition comprises about 57 wt% K2CO3, about 17 wt% CaCO3, and about 27 wt% Al2O3.

[0096] In certain variations, the sorbent composition comprises about 50 wt% K2CO3, about 15 wt% CaCl2, about 20 wt% Al2O3, and about 15 wt% CaCO3. In certain variations, the sorbent composition comprises about 55 wt% K2CO3, about 15 wt% CaCl2, about 15 wt% Al2O3, and about 15 wt% CaCO3. In certain variations, the sorbent composition comprises about 50 wt% K2CO3, about 13 wt% CaCl2, about 25 wt% Al2O3, and about 12 wt% CaCO3. Weight % Ratio of Components

[0097] In aspects of the foregoing, the relative amount of the one or more active components of the sorbent composition is increased relative to the other components in the sorbent composition to increase the CO2 capture capacity of the sorbent composition.

[0098] In some aspects of the foregoing, the weight percent (wt%) ratio of the total amount of active component for CO2 chemisorption (AC) to the total amount of moisture control additive (MCA) to the total amount of support material (SM) present in the sorbent composition is between about 1:0.0625:0 and about 1:1.5:1.5. In some embodiments, the wt% ratio of AC:MCA:SM present in the sorbent composition is between about 1:0.0125:0.1875 and about 1:0.5:0.625. In some embodiments, the wt% ratio of AC:MCA:SM present in the sorbent composition is between about 1:0.0625:0.125 and about 1:0.5:0.75. In some embodiments, the wt% ratio of AC:MCA:SM present in the sorbent composition is between about 1:0.166:0.25 and about 1:0.4:0.5.

[0099] In some variations, the wt% ratio of AC:MCA present in the sorbent composition is between about 1:0.0625 and about 1:1.5. In some variations, the wt% ratio of AC:MCA present 23sf-625386234037-20002.40 in the sorbent composition is between about between about 1:0.1 and about 1:1; between about 1:0.1 and about 1:0.75; between about 1:0.1 and about 1:0.5; between about 1:0.1 and about 1:0.25; between about 1:0.2 and about 1:1; between about 1:0.2 and about 1:0.75; between about 1:0.2 and about 1:0.5; between about 1:0.5 and about 1:1; or between about 1:0.5 and about 1:0.75. In certain variations, the wt% ratio of AC:MCA present in the sorbent composition is greater than about 1:0.125, greater than about 1:0.2, greater than about 1:0.5, greater than about 1:0.7, or greater than about 1:1. In certain variations, the wt% ratio of AC:MCA present in the sorbent composition is about 1:0.125, about 1:16, about 1:0.2, about 1:0.3, about 1:0.4, about 1:0.5, about 1:0.6, about 1:0.7, about 1:0.8, about 1:0.9, about 1:1, about 1:1.1, about 1:1.2, about 1:1.3, about 1:1.4, or about 1:1.5.

[0100] In some variations, the sorbent composition comprises K2CO3 and CaCO3 as active components and the wt% ratio of K2CO3:CaCO3 is between about 1:0.1 and about 1:0.5. In some variations, the wt% ratio of K2CO3:CaCO3 is about 1:0.2, about 1:0.3, or about 1:0.4. Granule Size Distribution

[0101] In some embodiments of the sorbent compositions described herein, the sorbent compositions are in the form granules (also referred to herein as “sorbent granules”). In some embodiments, the sorbent granules have an average granule size of between about 10 µm to about 5 mm. In some embodiments, the average granule size of the sorbent granules is between about 1 mm and 5 mm. In certain variations, the average granule size of the sorbent granules is between about 3 mm and 5 mm. In some variations, 90% of the granules are smaller than 5 mm.

[0102] In some variations of the foregoing, the average granule size of the sorbent granules is selected in order to balance the maximization of the carbon capture capacity and related kinetics of the sorbent granules, the minimization of the degradation of the sorbent granules during carbon capture, and the pressure drop across the aggregate of the sorbent granules during carbon capture, or any combination thereof. Therefore, in some embodiments, the average granule size is selected to maximize carbon capture capacity while maintaining structural integrity of the granules.

[0103] In other variations, the embodiments, the granule size of the sorbent granules is dependent on the type of reactor used for carbon capture. For example, in some embodiments, the sorbent granules are used in a fixed bed reactor, as described herein, and the granule size of the sorbent granules is (1) small enough such that the active component of the sorbent granules 24sf-625386234037-20002.40 can interact with gaseous CO2 during the absorption step and steam during the regeneration step of carbon capture as described herein, and (2) large enough to facilitate an acceptable pressure drop during the heating process during temperature swing operation. Acceptable pressure drops and methods for determining the same are known by those skilled in the art. In some embodiments, the sorbent granules are used in a fixed bed reactor and the average granule size of the sorbent granules is between about 2 mm to about 5 mm. In certain embodiments, the average granule size is between about 3 mm and 5 mm. In certain embodiments, the average granule size is about 5 mm. In certain embodiments, the average granule size is about 4 mm. In certain embodiments, the average granule size is about 3 mm. In certain embodiments, the average granule size is about 2 mm.

[0104] In other embodiments, for example, the sorbent granules are used in a fluidized bed reactor and the granule size of the sorbent granules is between about 10 µm to about 2 mm. In some embodiments, the gas flow rate of the fluidized bed reactor about 0.04 m / s and the granule size of the sorbent granules is between about 10 µm to about 300 µm. In other embodiments, the gas flow rate of the fluidized bed reactor is about 0.7 m / s and the granule size of the sorbent granules is between about 100 µm to about 2 mm. In some embodiments, the size distribution of the sorbent granules is about 1 order of magnitude. Shape of the Sorbent Granules

[0105] In some embodiments, the sorbent granules are in the shape of a sphere and / or a cylinder. In some embodiments, the shape of the granules of the sorbent composition used for carbon capture is dependent on the type of reactor used. For example, in some embodiments, a fluidized bed reactor is used and the granules of the sorbent composition are in the shape of spheres. Pressure drop calculations for spheres and cylinders can be predicted for fixed bed reactors using methods known in the art. Distribution of Sorbent Components in Sorbent Granules

[0106] In some aspects of the foregoing, each granule of the sorbent granules comprise one or more active components for CO2 chemisorption, one or more moisture control additives, and one or more support materials, as described herein. In some embodiments, each granule of the sorbent granules further comprises a filler. In some embodiments, the distribution of the active component for CO2 chemisorption and the moisture control additive in each granule is sufficient to facilitate stabilization of the sorbent composition during carbon capture. For 25sf-625386234037-20002.40 example, in some embodiments, the active component for CO2 chemisorption (i.e., metal carbonate) and the moisture control additive in each granule are in sufficiently close proximity such that the moisture control additive can facilitate and maintain the formation of the hydrate form of the metal carbonate during carbon capture, as described herein. Production of Sorbent Granules

[0107] In another aspect, provided are methods of producing sorbent compositions comprising sorbent compositions as described herein. In some embodiments, the methods described herein produce sorbent compositions in the form of sorbent granules. In some embodiments, the methods described herein product sorbent compositions comprising an active component for CO2 chemisorption and a support material. Impregnation

[0108] In one variation, provided is a method of producing a sorbent composition (e.g., sorbent granules) comprising at least one moisture control additive as described herein via impregnation. In some variations, the method comprises: dissolving or suspending one or more active components for CO2 chemisorption in a solvent to form a solution, adding precursor granules to the solution, wherein the precursor granules comprise one or more moisture control additive, and mixing the solution to produce sorbent granules having a sorbent composition as described herein. In some variations, the method comprises: dissolving or suspending one or more active components for CO2 chemisorption in a solvent to form a solution, adding precursor granules to the solution, wherein the precursor granules comprise one or more support material, and mixing the solution to produce sorbent granules having a sorbent composition as described herein. In some variations, the method comprises: dissolving or suspending one or more active components for CO2 chemisorption in a solvent to form a solution, adding precursor granules to the solution, wherein the precursor granules comprise one or more moisture control additive, one or more support material, or any combination thereof, and mixing the solution to produce sorbent granules having a sorbent composition as described herein.

[0109] In some variations, the method further comprises separating the sorbent granules from the solution and drying the sorbent granules. In some embodiments, the one or more moisture control additives of the precursor granules is zeolite. In some embodiments, the one or more support material of the precursor granules is aluminum oxide or cerium oxide. In some embodiments, the precursor granules are aluminum oxide. In some embodiments, the precursor 26sf-625386234037-20002.40 granules are cerium oxide. In some embodiments, the solvent water. In some embodiments, the sorbent granules produced using the above impregnation method comprise about 10 wt% to about 30 wt% of the one or more active components for CO2 chemisorption. Wet Granulation

[0110] In another variation, provided is a method of producing sorbent granules of sorbent compositions as described herein via wet granulation. In some embodiments, the method of producing sorbent granules comprising at least one moisture control additive comprises: mixing chemical feed powders in a solvent to produce a mixture, wherein the chemical feed powders comprise one or more active component for CO2 chemisorption, one or more moisture control additive, and one or more support material in a solvent; extruding the mixture to produce an extruded product; spheronizing the extruded product to produce a spheronized product; and drying the spheronized product to produce sorbent granules having a sorbent composition as described herein.

[0111] In some embodiments, the method of producing sorbent granules comprising at least one moisture control additive comprises: mixing chemical feed powders in a solvent to produce a mixture, wherein the chemical feed powders comprise one or more active component for CO2 chemisorption, one or more moisture control additive, and one or more support material in a solvent; extruding the mixture to produce an extruded product; spheronizing the extruded product to produce a spheronized product; and drying the spheronized product to produce sorbent granules having a sorbent composition as described herein. In some embodiments, the solvent is water. In some embodiments, the solvent is an organic solvent. In some embodiments, the organic solvent is isopropanol.

[0112] In some embodiments, the sorbent granules are spherical in shape. Spherical granules are suitable for use in fixed bed and fluidized bed reactors for carbon capture. In some embodiments, the extruded product is dried between 150 °C and 200 °C. Crushing and Sieving

[0113] In another variation, provided is a method of producing sorbent granules of sorbent compositions as described herein via a crushing and sieving method (Figure 1). In some embodiments, the method of producing sorbent granules comprises: mixing chemical feed powders in a solvent to produce a mixture, wherein the chemical feed powders comprise one or more active component for CO2 chemisorption and one or more support material; and 27sf-625386234037-20002.40 extruding the mixture to produce an extruded product. In some embodiments, the method of producing sorbent granules comprises: mixing chemical feed powders in a solvent to produce a mixture, wherein the chemical feed powders comprise one or more active component for CO2 chemisorption and one or more support material; extruding the mixture to produce an extruded product; and drying the extruded product to produce a dry extruded product. In some embodiments, the method of producing sorbent granules comprises: mixing chemical feed powders in a solvent to produce a mixture, wherein the chemical feed powders comprise one or more active component for CO2 chemisorption and one or more support material; extruding the mixture to produce an extruded product; drying the extruded product to produce a dry extruded product; crushing the extruded product to produce a crushed product; and sieving the crushed product to produce sorbent granules having a sorbent composition as described herein.

[0114] In some embodiments, the method of producing sorbent granules comprising at least one moisture control additive comprises: mixing chemical feed powders to produce a mixture, wherein the chemical feed powders comprise one or more active component for CO2 chemisorption, one or more moisture control additive, and one or more support material in a solvent; extruding the mixture to produce an extruded product; and drying the extruded product to produce a dry extruded product. In some embodiments, the method of producing sorbent granules comprising at least one moisture control additive comprises: mixing chemical feed powders to produce a mixture, wherein the chemical feed powders comprise one or more active component for CO2 chemisorption, one or more moisture control additive, and one or more support material in a solvent; extruding the mixture to produce an extruded product; drying the extruded product to produce a dry extruded product; crushing the extruded product to produce a crushed product; and sieving the crushed product to produce sorbent granules. In some embodiments, the solvent is water. In some embodiments, the solvent is an organic solvent. In some embodiments, the organic solvent is isopropanol.

[0115] In some embodiments, the method further comprises crushing and sieving the sorbent granules to produce sorbent granules that are smaller and / or have a narrower size distribution. In some embodiments, the method further comprises sieving the sorbent granules to produce sorbent granules that are smaller and / or have a narrower size distribution.

[0116] In some embodiments, the chemical feed powders comprise an active component for CO2 chemisorption and a support material. In some embodiments, the chemical feed powders comprise an active component for CO2 chemisorption, a moisture control additive, and a support material. In some embodiments, the chemical feed powders are fresh as described 28sf-625386234037-20002.40 herein. In some embodiments the chemical feed powders are rejuvenated. In some embodiments, the chemical feed powders comprise fresh chemical feed powders, rejuvenated sorbent powders as described herein, or a combination thereof.

[0117] In some variations, the sorbent granules produced using the crushing and sieving method as described herein have a wt% of the active component for CO2 chemisorption of up to 80 wt%. The wt% of the active component for CO2 chemisorption of sorbent granules produced using the crushing and sieving method is significantly higher than the wt% of active component for CO2 chemisorption achievable using the impregnation method as described herein, which typically have a maximum of about 30 wt%.

[0118] In some embodiments, the sorbent granules are cylindrical in shape. Cylindrical granules are suitable for use in fixed bed reactors for carbon capture. In some embodiments, the sorbent granules have a granule size between about 2.5 mm and 5 mm. In some embodiments, the sorbent granules have a granule size between 2.7 mm and 4.5 mm with respect to the radius of the cylindrical shape. In some embodiments, the extruded product is dried between 150 °C and 200 °C. In some embodiments, the sorbent granules produced using the above crushing and sieving method comprise greater than 10 wt%, greater than 20 wt%, greater than 30 wt%, greater than 40 wt%, greater than 50 wt%, greater than 60 wt%, greater than 70 wt%, or greater than 80 wt% on a (dry weight basis) of the one or more active components for CO2 chemisorption. The higher wt% of the active components for CO2 chemisorption allows for a higher CO2 capture capacity and kinetics and can facilitate the use of smaller reactors at lower operating costs. Additionally, the crushing and sieving method produces sorbent granules at lower cost, with fewer steps, and higher yields than wet granulation method with spheronization described above, which can result in low yields of sorbent compositions comprising deliquescent components (e.g., K2CO3, Na2CO3, etc.).

[0119] In some embodiments, the chemical feed powders used in the wet granulation and crushing and sieving methods described herein comprise one or more active component for CO2 chemisorption, one or more moisture control additive, one or more support material, or any combination thereof in the form of a fresh powder. In some embodiments, the fresh powder of the active component for CO2 chemisorption, moisture control additive, and support material are fresh powders of the various components as described herein. For example, in some variations, the fresh powder of the moisture control additive is a powder of CaCl2, a powder of 13x zeolite, or any combination thereof; the fresh powder of the active component for CO2 chemisorption is a powder of K2CO3, a powder of Na2CO3, a powder of MgCO3, a 29sf-625386234037-20002.40 powder of CaCO3, a powder of Li2CO3, or any combination thereof; and the fresh powder of the one or more support material is a powder of Al2O3, a powder of CeO2, or any combination thereof. In certain embodiments, the powder of the active component for CO2 chemisorption is a precursor of K2CO3, such as KHCO3, which is converted to K2CO3 upon heating. In certain embodiments, the fresh powders referenced herein have an average size of about 50 µm or less. In certain embodiments, for example, the fresh powders referenced herein have an average size of about 5 µm, about 10 µm, about 20 µm, about 30 µm, about 40 µm, or about 50 µm.

[0120] In some variations of the foregoing, the one or more of the chemical feed powders are in the form of a fresh chemical feed powder, a rejuvenated sorbent powder, or any combination thereof. Extruded product made according to the methods described herein can be dried to produce sorbent granules according to the crushing and sieving method, as described herein, or spheronized as described herein with respect to the wet granulation method. For example, in one variation, provided is a method of producing sorbent granules comprising at least one moisture control additive as described herein via a crushing and sieving method, comprising: mixing rejuvenated sorbent powder and one or more fresh chemical feed powders to produce a mixture; extruding the mixture to produce an extruded product; drying the extruded product to produce a dry extruded product, crushing the extruded product to produce a crushed product, and sieving the crushed product to produce rejuvenated sorbent granules, as described herein. In such variations, the one or more fresh chemical feed powders comprise one or more of fresh powders of the various components of the sorbent composition.

[0121] In some embodiments, one or more fresh chemical feed powders are mixed with enated sorbent powder to dilute the amount of salts formed during the carbon capture process. In some embodiments, one or more fresh chemical feed powders are mixed with rejuvenated sorbent powder to dilute the concentration of the salt to a level that will not negatively impact the mechanical or chemical properties of the resulting sorbent granules. In some embodiments, the salt concentration of the rejuvenated sorbent powder is diluted to below about 5%, about 4%, about 3%, about 2%, or about 1%. In some embodiments, the salt formed during the carbon capture process is nitrate salt, sulfate salt, or any combination thereof.

[0122] The sorbent compositions (e.g., sorbent granules) provided herein may be produced using any suitable process, methods, and / or techniques known in the art. For example, sorbent granules as described herein may be produced using the extrusion-spheronization method as described in WO2023107668, which is hereby incorporated by reference in its entirety, or extrusion-drying methods. 30sf-625386234037-20002.40 Carbon Capture

[0123] In another aspect, provided herein are systems and methods for capturing and discharging CO2 from a gaseous CO2 stream using a sorbent composition as described herein via a modified temperature swing adsorption process. In some variations, the gaseous CO2 stream is flue gas. In some variations, the gaseous stream comprises between about 2% and 40% CO2 by volume. In certain variations, the gaseous stream comprises between about 3.7% and about 20% by volume. In some embodiments, the humidity of the gaseous CO2 stream is between about 10% RH and about 100% RH non-condensing. In some embodiments, the temperature of the gaseous CO2 stream is about 70 °C or less. For example, in some embodiments, the temperature of the gaseous CO2 stream is about 60 °C.

[0124] The systems and methods described herein are effective at removing at least 80% of CO2 from the gaseous stream. In some embodiments, systems and methods described herein are effective at removing at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or at least 99.5% of CO2 from the gaseous stream. In some embodiments, the systems and methods for carbon capture described herein have a carbon capture capacity of between about 1.6 and about 3.0 mmol of CO2 per gram of sorbent material. In some embodiments, the utilization of a sorbent composition as disclosed herein eliminates the need to treat the gaseous stream comprising CO2 prior to absorption during carbon capture, such as by drying the gaseous CO2 stream to reduce the moisture content prior to absorption.

[0125] Figure 2 is a diagram of a process for capturing and discharging CO2 from a gaseous CO2 stream in which CO2 is removed from the gaseous stream by adsorption or chemical reaction using a sorbent composition as described herein and is discharged from the system to produce a CO2 enriched steam.

[0126] Figure 3 is a diagram of a system for capturing and discharging CO2 from a gaseous CO2 stream. With reference to Figure 3, in some embodiments, the system for capturing and discharging CO2 from a gaseous CO2 stream (200) may include an input for a gaseous CO2 stream (201), a reactor comprising a sorbent composition as described herein (203), a first gaseous outlet configured to output a gaseous stream (205), wherein the gaseous stream has a lower concentration of CO2 than the gaseous CO2 stream, a blower unit (207) in-line with a first heater unit (209), which can blow air through the reactor (203) during the cooling step and hot air via the heater unit (209) during the absorption and drying steps, and a second gaseous 31sf-625386234037-20002.40 outlet configured to output the air (211), a carrier source (213) configured to output a carrier gas (e.g., steam or gaseous CO2), which is in-line with a second heater unit (215) configured to optionally heat the carrier gas, and is configured to provide the carrier to the reactor (203) during the regeneration step, a heat exchanger (217) configured to receive the carrier gas and an enriched CO2 stream from the reactor (203) and configured to condense the carrier gas, and a CO2 outlet (219) configured to receive the enriched CO2 stream and discharge the CO2 enriched stream. In some embodiments of the systems and methods of the foregoing, the second gaseous outlet configured to output the air is configured to input the air into the blower unit (i.e., recirculate the air).

[0127] In one aspect, provided herein is a system for capturing and discharging CO2 from a gaseous CO2 stream, comprising a CO2 source configured to output a gaseous CO2 stream; a reactor configured to receive the gaseous CO2 stream, wherein the reactor comprises a sorbent composition, wherein the sorbent composition comprises one or more active components for CO2 chemisorption, one or more moisture control additives, and one or more support materials, wherein the gaseous CO2 stream contacts the sorbent composition (i.e., adsorption); and a first gaseous outlet configured to output a gaseous stream, wherein the gaseous stream comprises a lower concentration of CO2 than the gaseous CO2 stream. In some embodiments, the gaseous CO2 stream has a CO2 concentration of between about 2% to about 40% CO2 by volume. In some embodiments, the gaseous CO2 stream has a CO2 concentration of between about 3.7% and about 20% by volume. In some embodiments, the gaseous CO2 stream has a temperature of about 70 °C or less. In some embodiments, the gaseous CO2 stream has a temperature of between about 25 °C and about 60 °C.

[0128] In some embodiments, a preconditioning step is utilized (i.e., a pretreatment step). In some embodiments, the sorbent composition is pretreated (i.e., contacted) with carrier gas prior to adsorption (i.e., contacting with a gaseous CO2 stream). In some embodiments, the carrier gas used to pretreat the sorbent composition is steam, nitrogen, or a combination thereof. In some embodiments, the pretreatment step hydrates the sorbent composition. In some embodiments, the pretreatment comprises 80% nitrogen and 20% water vapor. In some embodiments, the pretreatment step is performed prior to contacting the sorbent composition with the gaseous CO2 stream as described herein. In some embodiments, pretreatment of the sorbent composition with the carrier gas facilitates the formation of the stable hydrate form of a metal carbonate of the sorbent composition. 32sf-625386234037-20002.40

[0129] In some embodiments, the system further comprises a blower unit configured to output air, wherein the reactor is configured to receive the air, and a second gaseous outlet configured to output the air. In some embodiments, the system further comprises a heater unit, wherein the heater unit is in-line with the blower unit and is configured to heat air. In some embodiments, the heater unit heats the air to between about 110 °C and about 200 °C. In certain embodiments, the heater unit heats the air to 150 °C. In certain embodiments, the blower is configured to output hot air and the second gaseous outlet is configured to output hot air. In some embodiments, the air is cold (e.g., during the cooling step as described herein). In some embodiments, the temperature of the cold air is between about 10 °C and about 70 °C. In certain embodiments, the temperature of the cold air is about 45 °C. In certain embodiments, the blower is configured to output cold air and the second gaseous outlet is configured to output cold air. In some embodiments, the optimal pressure of the air in the reactor is calculated based on the pressure drop across the reactor vessel. For example, in some variations, the optimal gauge pressure of the air is between about 0.7 and 1.0 bar. Pressure drops can be calculated according to known methods in the art.

[0130] In some embodiments, the system comprises a heater unit. In some embodiments, the heater unit is in line with the blower unit. In some embodiments, the heater unit is an electrical resistive heater. In some embodiments, the heater unit is a heat exchanger.

[0131] In some embodiments, the system comprises a carrier source configured to output a carrier gas (e.g., steam or gaseous CO2). In some embodiments, the carrier gas is steam, gaseous CO2, or a combination thereof. In some embodiments, the carrier gas is steam. In some embodiments the carrier gas is gaseous CO2. In some embodiments, system further comprises a second heater unit which is in line with the carrier source and is configured to optionally heat the carrier. In some embodiments, the carrier gas is heated to between about 120 °C and 200 °C.

[0132] In some embodiments, the carrier source is configured to output steam, wherein the reactor is configured to receive the steam, wherein the steam contacts the sorbent composition, and a CO2 outlet configured to discharge CO2 enriched steam, wherein the CO2 enriched steam comprises a higher concentration of CO2 than the gaseous CO2 stream. In some embodiments, the steam source has a gauge pressure of between about 0.1 bar and about 1.0 bar. In certain embodiments, the steam has a pressure of about 0.4 bar. In some embodiments, the steam source has a temperature of between about 120 °C and about 200 °C. In certain embodiments, the steam has a temperature of about 140 °C. In some embodiments, the CO2 33sf-625386234037-20002.40 enriched steam has a CO2 concentration of between about 10% and about 99% by volume. In some embodiments, the CO2 enriched steam has a CO2 concentration of between about 10% and about 90% by volume. In certain embodiments, the CO2 enriched steam has a CO2 concentration of about at least about 80% by volume. In certain embodiments, the CO2 enriched steam has a CO2 concentration of about 80% by volume. In some embodiments, the steam source has a humidity of 100%.

[0133] In some embodiments, the system comprises a heat exchanger for cooling the reactor. In some embodiments, the heat exchanger is configured to receive the carrier gas and an enriched CO2 stream from the reactor and to condense the carrier gas. In some embodiments, the system further comprises a condensate outlet configured to output the condensate formed during the cooling step.

[0134] In some embodiments, the system comprises a CO2 outlet configured to receive the enriched CO2 stream from the reactor and discharge the CO2 enriched steam during the regeneration step.

[0135] In some embodiments of the foregoing systems, the system is a closed system (e.g., external gases are not introduced into the system during carbon capture using the system).

[0136] In another aspect, provided herein is a method of capturing and discharging CO2 comprising: contacting a gaseous CO2 stream with a sorbent composition to produce a gaseous stream comprising a lower concentration of CO2 than the gaseous CO2 stream, wherein the sorbent composition comprises one or more active components for CO2 chemisorption, one or more moisture control additives, and one or more support materials, as described herein. In another aspect, provided herein is a method of capturing and discharging CO2 comprising: contacting a gaseous CO2 stream with a sorbent composition to produce a gaseous stream comprising a lower concentration of CO2 than the gaseous CO2 stream, wherein the sorbent composition comprises one or more active components for CO2 chemisorption, one or more moisture control additives, and one or more support materials; and heating the sorbent composition. In another aspect, provided herein is a method of capturing and discharging CO2 comprising: contacting a gaseous CO2 stream with a sorbent composition to produce a gaseous stream comprising a lower concentration of CO2 than the gaseous CO2 stream, wherein the sorbent composition comprises one or more active components for CO2 chemisorption, one or more moisture control additives, and one or more support materials, as described herein; heating the sorbent composition; and regenerating the sorbent composition. In another aspect, 34sf-625386234037-20002.40 provided herein is a method of capturing and discharging CO2 comprising: contacting a gaseous CO2 stream with a sorbent composition to produce a gaseous stream comprising a lower concentration of CO2 than the gaseous CO2 stream, wherein the sorbent composition comprises one or more active components for CO2 chemisorption, one or more moisture control additives, and one or more support materials, as described herein; heating the sorbent composition; regenerating the sorbent composition; and drying the sorbent composition. In another aspect, provided herein is a method of capturing and discharging CO2 comprising: contacting a gaseous CO2 stream with a sorbent composition to produce a gaseous stream comprising a lower concentration of CO2 than the gaseous CO2 stream, wherein the sorbent composition comprises one or more active components for CO2 chemisorption, one or more moisture control additives, and one or more support materials, as described herein; heating the sorbent composition; regenerating the sorbent composition; drying the sorbent composition; and cooling the sorbent composition.

[0137] In another aspect, provided herein is a method of capturing and discharging CO2 comprising: contacting a gaseous CO2 stream with a sorbent composition in a reactor to produce a gaseous stream comprising a lower concentration of CO2 than the gaseous CO2 stream, wherein the sorbent composition comprises one or more active components for CO2 chemisorption, one or more moisture control additives, and one or more support materials, as described herein. In another aspect, provided herein is a method of capturing and discharging CO2 comprising: contacting a gaseous CO2 stream with a sorbent composition in a reactor to produce a gaseous stream comprising a lower concentration of CO2 than the gaseous CO2 stream, wherein the sorbent composition comprises one or more active components for CO2 chemisorption, one or more moisture control additives, and one or more support materials; and heating the reactor. In another aspect, provided herein is a method of capturing and discharging CO2 comprising: contacting a gaseous CO2 stream with a sorbent composition in a reactor to produce a gaseous stream comprising a lower concentration of CO2 than the gaseous CO2 stream, wherein the sorbent composition comprises one or more active components for CO2 chemisorption, one or more moisture control additives, and one or more support materials, as described herein; heating the reactor; and regenerating the sorbent composition. In another aspect, provided herein is a method of capturing and discharging CO2 comprising: contacting a gaseous CO2 stream with a sorbent composition in a reactor to produce a gaseous stream comprising a lower concentration of CO2 than the gaseous CO2 stream, wherein the sorbent composition comprises one or more active components for CO2 chemisorption, one or more moisture control additives, and one or more support materials, as described herein; heating the 35sf-625386234037-20002.40 reactor; regenerating the sorbent composition; and drying the sorbent composition. In another aspect, provided herein is a method of capturing and discharging CO2 comprising: contacting a gaseous CO2 stream with a sorbent composition in a reactor to produce a gaseous stream comprising a lower concentration of CO2 than the gaseous CO2 stream, wherein the sorbent composition comprises one or more active components for CO2 chemisorption, one or more moisture control additives, and one or more support materials, as described herein; heating the reactor; regenerating the sorbent composition; drying the sorbent composition; and cooling the sorbent composition.

[0138] In some variations, the active component for CO2 chemisorption is one or more metal carbonates. In certain variations, the metal carbonate is in the form of a stable hydrate, as described herein. In some embodiments, at least a portion of the CO2 from the gaseous CO2 stream contacted with the sorbent composition is chemisorbed to the sorbent composition.

[0139] In some embodiments of the foregoing, the CO2 of the gaseous CO2 stream reacts with one or more metal carbonates (i.e., the active component for CO2 chemisorption) of the sorbent composition that is in the form of a stable hydrate when the gaseous CO2 is contacted with the sorbent composition according to the following equation: ^^^^x^^^^^^^^3 ∙ y^^^^2^^^^ (^^^^) + ^^^^^^^^2(g) → ^^^^a^^^^^^^^^^^^3(s) + b^^^^2^^^^(^^^^)where x, y, a, and b are integers or fractions. In some embodiments, the sorbent compositioncomprises K2CO3 and the stable hydrate is in the form of ^^^^2^^^^^^^^3 ∙ 1.5^^^^2^^^^(^^^^). In someembodiments, the one or more metal carbonates is in the form of a stable hydrate (^^^^2^^^^^^^^3∙ 1.5^^^^2^^^^(^^^^)) during the absorption (i.e., contacting), regeneration, drying, and cooling steps as herein.

[0140] In some embodiments described herein, regenerating the sorbent composition is a modified temperature swing adsorption process. For example, in some embodiments, the sorbent composition comprises K2CO3 as the active component for CO2 chemisorption and a moisture control additive as described herein (e.g., CaCl2) and regenerating the sorbent composition proceeds according to the following chemical reaction: ^^^^2^^^^^^^^3 ∙ 1.5^^^^2^^^^(^^^^) + ^^^^^^^^2(^^^^) ← 2^^^^^^^^^^^^^^^^3(^^^^) + 0.5^^^^2^^^^(^^^^)wherein wet CO2 is released from the reactor.

[0141] In some of the variations of the foregoing, the methods described herein capture and discharge CO2 using significantly lower energy consumption than methods known in the art. In 36sf-625386234037-20002.40 some variations, the energy required to regenerate the sorbent during CO2 capture and discharge according to the systems and methods described herein is significantly lower than methods known in the art.

[0142] In some variations, contacting the sorbent composition with a gaseous CO2 stream results in the adsorption of CO2 to the sorbent composition (i.e., the adsorption step of carbon capture).

[0143] In some embodiments, contacting the gaseous CO2 stream with a sorbent composition comprises heating to between about 60 °C reactor is heated to between about 60 °C and about 140 °C. In some embodiments, the reactor is heated to between about 105 °C and about 120 °C. In some embodiments, the reactor is heated to between about 110 °C. In some embodiments, heating the reactor comprises blowing hot air on the reactor. In some embodiments, the hot air is between about 105 °C and 120 °C. In some embodiments, the reactor is heated to a temperature in which the hydrate form of K2CO3·1.5H2O(s) is thermodynamically and / or kinetically favored over the dehydrated form of K2CO3(s). In some embodiments, the reactor is heated without the introduction of external gases. In some embodiments, heating the reactor comprises heating the sorbent composition to between about 105 °C and about 120 °C. In some embodiments, the sorbent composition is heated by contacting the sorbent composition with hot air.

[0144] In some variations, regenerating the sorbent composition results in the discharge or release of CO2 from the sorbent composition. In some variations, regenerating the sorbent composition comprises contacting the sorbent composition with a carrier gas. In some embodiments, the carrier gas is CO2, steam, or a combination thereof. In some embodiments, the carrier gas is CO2. In some embodiments, CO2 is used as the carrier gas when a low moisture content of the reactor is desired during the regeneration step. In other embodiments, steam is used as the carrier gas moisture content of the reactor is desired during the regeneration step. In some embodiments, CO2 and steam are used as the carrier gas to control the moisture content of the reactor during the regeneration step.

[0145] In some embodiments, the carrier gas is steam, and contacting the sorbent composition with steam produces a CO2 enriched steam, wherein the CO2 enriched steam has a higher CO2 concentration than the gaseous CO2 stream. In some variations, the temperature of the steam is between about 115 °C and about 170 °C. In some embodiments, the superheated steam has a pressure of between about 0.1 bar and about 1.0 bar. In some variations, the steam 37sf-625386234037-20002.40 is superheated steam. In some variations, the steam is saturated steam. In such embodiments, a heater is required to heat the supersaturated steam. In some variations, regenerating the sorbent composition further comprises discharging the CO2 enriched steam. In some embodiments, the carrier gas facilitates mass and heat transfer in the reactor and accelerates the release of CO2 from the sorbent composition during regeneration. In some embodiments, contacting the sorbent composition with steam or superheated steam releases CO2 from the sorbent composition and regenerates the sorbent composition.

[0146] As discussed herein, the hydrate form of the metal carbonate of the sorbent composition can be regenerated at significantly lower temperatures and using less energy than carbon capture systems using solid carbonates that do not use the non-hydrate form (i.e., “dry carbonate”). For example, in some variations of the foregoing methods and systems for carbon capture using the sorbent composition described herein, the regeneration temperature is between about 110 °C and about 200 °C. The relatively low temperature of the regeneration step of the systems and methods described herein as compared to system and methods known in the art, in which regeneration temperatures are typically 850 °C, result in lower energy consumption. The use of steam during the regeneration step is facilitated by the use of one or more moisture control additives in the sorbent composition which stabilizes the sorbent composition in moist and / or humid conditions and facilitates the formation and maintenance of the hydrate form of the metal carbonate of the sorbent composition.

[0147] In some embodiments, the pressure of the system for capturing and discharging CO2 from a gaseous CO2 stream is increased to increase the efficiency of carbon capture. For example, in some embodiments, the pressure of the gaseous CO2 stream is increased to increase the carbon capture efficiency.

[0148] In some variations, drying the sorbent composition comprises contacting the sorbent composition with air to remove excess moisture from the reactor. In some variations, drying the sorbent composition comprises blowing air into the reactor to displace the carrier gas from the reactor comprising the sorbent composition. In some variations, the air is compressed air. In some variations, the air is hot air. In some variations, the moisture is gaseous, condensate, or a combination thereof. In certain variations, drying the sorbent composition comprises contacting the sorbent composition with hot air to remove excess moisture from the reactor. In some variations, drying the sorbent composition prevents condensate formation during the cooling step. In some variations, the temperature of the hot air for drying the sorbent composition is greater than the temperature of the steam used to regenerate the sorbent composition. For 38sf-625386234037-20002.40 example, in some variations, the temperature of the hot air for drying the sorbent composition is greater than about 170 °C. In other variations, the temperature for drying the sorbent composition is about the same as the temperature of the steam used to regenerate the sorbent composition. In some variations, the amount of moisture remaining in the reactor after removal of the excess moisture is sufficient to maintain the hydrate form of the metal carbonate salt during the drying and / or cooling steps.

[0149] In some variations, cooling the sorbent composition comprises cooling the sorbent composition to between about 10 °C and about 70 °C. In some embodiments, the sorbent composition is cooled by contacting the sorbent composition with cool air.

[0150] In some embodiments, the minimum humidity of the absorption step as described herein is the relative humidity at which the metal carbonate forms a stable hydrate at the temperature of absorption. In some embodiments, the metal carbonate is potassium carbonate and the minimum humidity of the regeneration step is 5% at 20 °C. In some embodiments, the maximum relative humidity of the heating step is the deliquescence point of the metal carbonate of the sorbent composition. In the embodiments, the metal carbonate is potassium carbonate and the maximum relative humidity is 44% at 60 °C. In some embodiments, the maximum relative humidity is 100% RH non-condensing.

[0151] In any of the methods and systems described herein, the sorbent composition is in the form of granules.

[0152] With a heat recovery efficiency estimate between 30-70%, the overall thermal energy requirement to capture carbon with this technology can be as low as 0.36-0.84 GJ / tonne-CO2.

[0153] In some embodiments, the reactor wall of the foregoing systems comprises a surface treatment or modification. In some embodiments, the reactor wall is modified or treated with a coating that prevents the sorbent composition from sticking to the reactor walls after one or more carbon capture cycles. In certain embodiments, the coating is a Teflon®, silicone, or similar coating.

[0154] In another aspect, provided herein is a method for treating a reactor wall with a coating to prevent sticking, comprising: treating a reactor wall with a coating to preventing sticking of a sorbent composition to the reactor wall, wherein the coating to prevent sticking is Teflon®, silicone, or any combination thereof, wherein the reactor is a reactor for carbon 39sf-625386234037-20002.40 capture, and wherein the sorbent composition is a deliquescent sorbent composition. In some embodiments, the deliquescent sorbent composition is a composition as described herein. In some embodiments, the deliquescent sorbent composition is a sorbent composition comprising K2CO3. Rejuvenation of Spent Sorbents

[0155] In another aspect, provided herein is a method of rejuvenating spent sorbent. Spent sorbents are typically disposed of sorbent materials which have undergone one or more carbon capture cycles. In some embodiments, the spent absorbent has lost its chemical activity. In some embodiments, the spent sorbent has undergone one or more temperature and humidity cycles for capturing CO2. In some embodiments, the spent absorbent has lost its chemical activity for capturing CO2. In certain embodiments, the spent absorbent has lost at least 20% of its chemical activity for capturing CO2.

[0156] In some embodiments, the method of rejuvenating spent sorbent comprises: pulverizing the spent sorbent into a rejuvenated sorbent powder. In some embodiments, pulverizing the spent sorbent into a rejuvenated sorbent powder includes the presence of water. In some embodiments, the spent sorbent is pulverized into a rejuvenated sorbent powder with a size distribution the same as the feed chemical powders, typically smaller than 50 µm.

[0157] In some variations, the method of rejuvenating spent sorbent further comprises using the rejuvenated sorbent powder as the chemical feed powder in a method for producing sorbents as described herein. The moisture content of the rejuvenated sorbent powder should be low enough such that the rejuvenated sorbent powder remains in the form of a powder after pulverization. In other variations, the method of rejuvenating spent sorbent further comprises using the rejuvenated sorbent powder in combination with a fresh chemical feed powder in a method of producing sorbents as described herein. For example, as shown in Figure 1, pulverized spent sorbent can be added to a mixer with fresh chemical feed powder as described herein, extruded, spheronized, and dried to obtain a sorbent composition. EXAMPLES

[0158] The presently disclosed subject matter will be better understood by reference to the following Examples, which are provided as exemplary of the invention, and not by way of limitation. Example 1 40sf-625386234037-20002.40 PREPARATION OF SORBENT COMPOSITIONS VIA CRUSHING AND SIEVING METHOD

[0159] Exemplary sorbent compositions, as set forth in Table 1, were prepared by mixing fresh feed powders of the sorbent components having a granule size of 200 µm or smaller and purity of at least 97% until an even mixture was obtained. While continuing to mix, water, as set forth in Table 1, was then added to the mixture at a rate of 1-10 mL / s. The mixture was mixed for an additional 20 min, heated in a convection oven at 190 °C for up to 2 hours, cooled to room temperature, and then sieved using a sieve with 2.7 mm and 4.5 mm square-hole sizes. The resulting sorbent granules had a diameter of between 2.7 mm and 4.5 mm, measured by the width of a cylinder, and any sorbent granules with a size greater than 4.5 mm were crushed and sieved again to increase the yield of granules with diameters between 2.7 mm and 4.5 mm. Table 1. Sorbent CompositionsExample 2 ABSORPTION PROFILE OF SORBENT

[0160] The absorption profile of a granular sorbent composition described in Table 2 below was obtained using a fixed bed reactor configuration (Figure 4). The sorbent granules were prepared using the same method as described in Example 1. A precondition hydration step was performed using 80% N2 and 20% water vapor. In Figure 4, the baseline corresponds to the known %CO2 of the gaseous stream introduced into the fixed bed reactor and the area between the baseline (the known %CO2 of the gaseous stream) and the absorption profile curve 41sf-625386234037-20002.40 corresponds to the amount of CO2 captured by the sorbent composition over time. Collection of the absorption data began after flue gas with a consistent gas composition was introduced into the fixed bed reactor and the %CO2 was close to the baseline. Surprisingly, at early time points of the absorption phase (x-axis of Figure 4), the observed %CO2 was close to 0.00%, which indicates that almost all of the CO2 present in the flue gas was captured by the sorbent, reflecting excellent kinetics. See Figure 4. As the flue gas continued to flow, the sorbent slowly became saturated with CO2, and the %CO2 curve gradually increased to approach the baseline, indicating the end of the absorption phase. See Figure 4. Table 2.

[0161] Figure 5 shows the absorption profile of the same sorbent composition under the same conditions described above except that no preconditioning hydration step was performed. The difference in absorption profiles shown in Figures 4 and 5 indicates that the preconditioning hydration step provides a 675% boost in the kinetics of CO2 absorption and results in a higher overall capture efficiency of the sorbent. Example 3 REGENERATION PROFILE OF SORBENT

[0162] The regeneration profile of a granular sorbent composition described in Table 3 below was obtained using a fixed bed reactor configuration (Figure 6). The sorbent granules were prepared using the same method as described in Example 1. Figure 6 shows the ratio of the partial pressure of CO2 to the partial pressure of argon (internal standard used to quantify CO2) and reactor temperature over time during low temperature regeneration of the sorbent. Superheated steam was used as the sweep gas to facilitate heat and mass transport during the regeneration reaction. The temperature of the reaction was held constant around 116 °C and CO2 release from the sorbent was evident by the peak near 0.8 hours o (Figure 6). The ratio of the partial pressure of CO2 to the partial pressure of argon (pCO2 / pAr) baseline input shows the environmental background CO2 concentration (Figure 6). Overall, this data indicates that regeneration of CO2 at around 116 °C under superheated steam is achievable and fast, confirming that regeneration with steam on a larger scale is feasible and less energy-intensive 42sf-625386234037-20002.40 than methods known in the art which often require a temperature of about 850 °C for regeneration. Table 3. Sorbent CompositionExample 4 REJUVENATION OF SPENT SORBENT

[0163] The carbon capture performance of fresh (non-rejuvenated) granule sorbent and rejuvenated granule sorbent having a sorbent composition described in Table 4 using a fixed bed reactor is shown in Figure 4. The fresh sorbent was prepared using the method described in Example 1. The rejuvenated sorbent was prepared using the method described in Example 1 except that a certain portion of pulverized spent powders comprising the sorbent composition described in Table 4 were used in combination with fresh feed powders. The sorbent capacity of the non-rejuvenated (fresh) sorbent and the rejuvenated sorbent was 3.54 x 10-2g-CO2 / mL and 3.46 x 10-2g-CO2 / mL, respectively, equating to a 3% difference in sorbent capacities (Figure 7). This data supports that rejuvenation of spent sorbent is feasible. Table 4. Sorbent CompositionExample 5 PREPARATION OF SORBENT COMPOSITIONS VIA IMPREGNATION METHOD

[0164] Sorbent granules were prepared using an impregnation method in which 27.5 g of K2CO3 was dissolved in 100 mL water, and 500 g of 13X zeolite beads measuring size 3~5mm in diameter were slowly added into the prepared K2CO3 solution while stirring. The resulting mixture was allowed to sit for 2 hours. The zeolite beads were then removed from the solution and dried in an oven at between 150 ˚C and 200 ˚C until no visible moisture was observed to afford the sorbent.

[0165] The sorbent was loaded into a fixed bed reactor of a volume 0.1 m3, and gas with an absolute humidity 7.8%v, which translates to a CO2 concentration of 3.7%v, was introduced 43sf-625386234037-20002.40 into the reactor system to test the CO2 capture performance of the sorbent. The absorption temperature was 60 ˚C, and the pressure is near atmospheric. The CO2 concentration of the gas introduced into the reactor (line with squares) and the gas exiting the reactor (line with triangles) were measured, and the difference between these curves indicates the CO2 captured by the sorbent (Figure 8). Example 6 SORBENT REACTOR UNPACKING

[0166] Sorbent granules with the compositions described in Table 5 were prepared using the same method as Example 1. The sorbent granules were evaluated for the ease at which the sorbent granules were subsequently removed from the reactor after one or more cycles and assigned an “Unpacking Score” ranging from 0 to 5, as defined in Table 6 below. A lower unpacking score indicates greater ease of removal of the sorbent granules from the reactor after carbon capture, suggesting higher resistance of the sorbent granules to the humidity content during capture (85% RH) and the moisture introduced during steam regeneration (100% RH). As shown in Table 5, the unpacking score decreases as the wt% ratio of CaCl2, a moisture control additive, to K2CO3, an active component for CO2 chemisorption, increases. This suggests that sorbent granules having a higher ratio of CaCl2 have a greater resistance to moisture during carbon capture due to the formation of the stable hydrate form of K2CO3 during carbon capture, which is facilitated by CaCl2. Granules of sorbent composition 7, which did not include a moisture control additive, had the highest unpacking score of 5. Table 5. Sorbent CompositionsTable 6. Unpacking Scores 44sf-625386234037-20002.40Example 7 IMPACT OF MOISTURE CONTROL ON ABSORPTION CAPACITY AND KINETICS

[0167] The absorption profile of a granule sorbent compositions was obtained using a fixed bed reactor configuration. The sorbent granules were generally prepared in accordance with protocols described in Example 1. The absorption capacity of the sorbent granules comprising 12 wt% CaCl2 was slightly lower (11% less) than the sorbent granules comprising 10 wt% CaCl2. However, the slight increase in CaCl2 to 12 wt% increased the kinetics by 19% as compared to the 10 wt% CaCl2 sorbent granules and the overall carbon capture efficiency of the sorbent granules. Example 8 CARBON CAPTURE CAPACITY AND KINETICS STUDY

[0168] Absorption data for the two sorbent compositions provided below in Table 7, which were prepared according to the method in Example 1, was obtained using the same procedure as outlined in Example 2. The carbon capture capacity of sorbent composition no.1 in Table 9 was 0.037 g / mL and had a rate constant of 0.085 m3.mol-1·s-1. The carbon capture capacity of sorbent composition no.2 in Table 9 was 0.02 g / mL and had a rate constant of 0.041 m3.mol- 45sf-625386234037-20002.40 1·s-1. These results demonstrate the substitution of CaCO3 with 13x zeolite, which both adsorbs and absorbs CO2, enhances sorbent carbon capture capacity and kinetics. Table 7. Sorbent CompositionsExample 9 SUPPORT MATERIAL AND DENSITY STUDY

[0169] To isolate the effect of Al2O3 on density of the sorbent and sorbent performance, sorbent granules with a sorbent composition provided below in Table 8 were prepared according to the method in Example 1 and tested according to the same procedure outline in Example 2. Sorbent composition 1 from Table 10 had a density of 1.138 g / mL, a capture capacity of 0.11 g / mL, and a rate constant 0.121 m3.mol-1·s-1. Sorbent composition 2 from Table 10 had a density of 0.650 g / mL, a capture capacity of 0.088 g / mL, and a rate constant 0.03 m3.mol-1·s-1. Higher carbon capture and kinetics was expected for sorbent composition 2 due to the increased amount of K2CO3. However, the results suggest that the addition of Al2O3 increases the density of the sorbent as well as the carbon capture capacity and kinetics. Table 8. Sorbent Compositions46sf-6253862

Claims

34037-20002.40 CLAIMS What is claimed is:

1. A sorbent composition for carbon capture, comprising: an active component for CO2 chemisorption; a moisture control additive; and a support material.

2. The sorbent composition of claim 1, wherein the active component for CO2 chemisorption is a metal carbonate.

3. The sorbent composition of claim 2, wherein the metal carbonate comprises K2CO3, Na2CO3, Li2CO3, CaCO3, MgCO3, or any combination thereof.

4. The sorbent composition of claim 2 or 3, wherein the metal carbonate comprises deliquescent.

5. The sorbent composition of claim 4, wherein the metal carbonate comprises K2CO3, Na2CO3, or a combination thereof.

6. The sorbent composition of any one of claims 2 to 5, wherein the moisture control additive increases the stability of the sorbent composition in a moist and / or humid environment.

7. The sorbent composition of claim 6, wherein the moist and / or humid environment is an environment having a relative humidity (RH) greater than a deliquescent point of the metal carbonate.

8. The sorbent composition of any one of claims 2 to 7, wherein the metal carbonate comprises in the form of a hydrate.

9. The sorbent composition of any one of claims 1 to 8, wherein the moisture control additive comprises CaCl2, KCl, silica gel, celite, aluminosilicate, potassium acetate, sodium acetate, activated carbon, or any combination thereof.

10. The sorbent composition of claim 8, wherein the aluminosilicate comprises magnesium aluminosilicate, bentonite, a zeolite, or any combination thereof.

11. The sorbent composition of claim 8, wherein the zeolite comprises clinoptilolite or 13x zeolite.

12. The sorbent composition of any one of claims 1 to 11, wherein the moisture control additive absorbs gaseous or liquid water from the moist and / or humid environment, adsorbs gaseous or liquid water from the moist and / or humid environment, or a combination thereof. 47sf-625386234037-20002.40 13. The sorbent composition of claim 12, wherein the moisture control additive absorbs gaseous or liquid water from the moist and / or humid environment.

14. The sorbent composition of claim 13, wherein the moisture control additive comprises CaCl2.

15. The sorbent composition of claim 12, wherein the moisture control additive adsorbs gaseous or liquid water from the moist and / or humid environment.

16. The sorbent composition of claim 15, wherein the moisture control additive comprises a zeolite.

17. The sorbent composition of claim 16, wherein the zeolite comprises 13x zeolite, celite, or a combination thereof.

18. The sorbent composition of claim 17, wherein the zeolite comprises 13x zeolite.

19. The sorbent composition of any one of claims 1 to 18, wherein the support material comprises aluminum oxide, cerium oxide, activated carbon, pseudoboehmite, or any combination thereof.

20. The sorbent composition of claim 1, wherein the moisture control additive and the support material are the same material.

21. The sorbent composition of any one of claims 1 to 20, wherein the composition comprises about 30 wt% to about 80 wt% of one or more active components for CO2 chemisorption, about 5 wt% to about 60 wt% of one or more moisture control additives, and about 0 wt% to about 60 wt% of support material.

22. The sorbent composition of claim 21, wherein the composition comprises about 40 wt% to about 80 wt% of K2CO3, CaCO3, or any combination thereof.

23. The sorbent composition of claim 20 or 21, wherein the composition comprises about 45 wt% to about 60 wt% of K2CO3.

24. The sorbent composition of any one of claims 21 to 23, wherein the composition comprises about 5 wt% to about 60 wt% of CaCl2, celite, zeolite, or any combination thereof.

25. The sorbent composition of claim 24, wherein the composition comprises about 5 wt% to about 20 wt% of CaCl2.

26. The sorbent composition of any one of claims 21 to 25, wherein the composition comprises about 0 wt% to about 60 wt% of Al2O3, CeO2, pseudoboehmite, or any combination thereof. 48sf-625386234037-20002.40 27. The sorbent composition of claim 26, wherein the composition comprises about 10 wt% to about 40 wt% of Al2CO3.

28. The sorbent composition of claim 21, wherein the composition comprises about 40 wt% to about 80 wt% K2CO3, about 5 wt% to about 20 wt% CaCl2, and about 5 wt% to about 40 wt% Al2O3.

29. The sorbent composition of claim 21, wherein the composition comprises about 40 wt% to about 80 wt% K2CO3, about 5 wt% to about 20 wt% CaCl2, about 5 wt% to about 40 wt% Al2O3, and about 5 wt% to 15 wt% CaCO3.

30. The sorbent composition of claim 21, wherein the composition comprises about 52 wt% K2CO3, about 16 wt% CaCO3, about 25 wt% Al2O3, and about 8 wt% CaCl2.

31. The sorbent composition of claim 21, wherein the composition comprises about 55 wt% K2CO3, about 10 wt% CaCO3, about 25 wt% celite, and about 10 wt% CaCl2.

32. The sorbent composition of claim 21, wherein the composition comprises about 55 wt% K2CO3, about 10 wt% CaCO3, about 25 wt% Al2O3, and about 10 wt% CaCl2.

33. The sorbent composition of any one of claims 1 to 32, wherein the wt% ratio of the active component for CO2 chemisorption to the moisture control additive present in the composition is between about 1:0.0625 and about 1:1.

5.

34. The sorbent composition of any one of claims 1 to 33, wherein the wt% ratio of the active component for CO2 chemisorption to the moisture control additive to the support material present in the composition is between about 1:0.0625:0 and about 1:1.5:1.

5.

35. The sorbent composition of any one of claims 1 to 34, wherein the sorbent composition is in the form of granules.

36. The sorbent composition of claim 35, wherein the granules have an average granule size of between about 1 mm and 5 mm.

37. The sorbent composition of claim 36, wherein the granules have an average granule size of between about 3 mm and 5 mm.

38. The sorbent composition of any one of claims 35 to 37, wherein the granules are spheres or cylinders.

39. The sorbent composition of any one of claims 35 to 38, wherein the metal carbonate and the moisture control additive in each granule is in sufficiently close proximity such that the 49sf-625386234037-20002.40 moisture control additive can facilitate and maintain the formation of a hydrate form of the metal carbonate during carbon capture.

40. A method of producing a sorbent composition for carbon capture, comprising: a) dissolving or suspending an active component for CO2 chemisorption in a solvent to form a solution; b) adding precursor granules to the solution, wherein the precursor granules comprise a moisture control additive, a support material, or both; and c) mixing the solution to produce sorbent granules.

41. The method of claim 40, further comprising separating the sorbent granules from the solution and drying the sorbent granules.

42. The method of claim 40 or 41, wherein the precursor granules is zeolite, aluminum oxide, cerium oxide, or any combination thereof.

43. A method of producing a sorbent composition for carbon capture, comprising: a) mixing chemical feed powders in a solvent to produce a mixture, wherein the chemical feed powders comprise an active component for CO2 chemisorption and a support material; b) extruding the mixture to produce an extruded product; and c) drying the extruded product to produce a dry extruded product.

44. The method of claim 43, further comprising d) crushing the extruded product to produce a crushed product; and e) sieving the crushed product to produce sorbent granules.

45. The method of claim 43 or 44, wherein the chemical feed powders comprise fresh chemical feed powders.

46. The method of any one of claims 43 to 45 wherein the chemical feed powders further comprise a moisture control additive.

47. The method of claim 46, wherein the moisture control additive comprises CaCl2 or zeolite, or a combination thereof. 50sf-625386234037-20002.40 48. The method of any one of claims 43, 44, 46, or 47, wherein the chemical feed powders comprise fresh chemical feed powders and rejuvenated sorbent powder and the sorbent granules are rejuvenated sorbent granules.

49. The method of claim 48, wherein the rejuvenated sorbent powder is produced by pulverizing spent sorbent.

50. The method of any one of claims 44 to 49, wherein the sorbent granules comprise up to 80 wt% of the active component for CO2 chemisorption.

51. The method of any one of claims 44 to 50, wherein the active component for CO2 chemisorption is K2CO3.

52. The method of any one of claims 44 to 51, further comprising sieving the sorbent granules to produce sorbent granules that are smaller and / or have a narrower size distribution.

53. The method of any one of claims 44 to 52, wherein the solvent is water.

54. The method of any one of claims 44 to 53, wherein the sorbent granules have a granule size between about 2.5 mm and about 5 mm.

55. The method of any one of claims 43 to 54, wherein the chemical feed powders have an average size of 50 µm or less.

56. A system for capturing and discharging CO2, comprising: a) a CO2 source configured to output a gaseous CO2 stream; b) a reactor configured to receive the gaseous CO2 stream, wherein the reactor comprises a sorbent composition of any one of claims 1 to 39; and c) a first gaseous outlet configured to output a gaseous stream, wherein the gaseous stream comprises a lower concentration of CO2 than the gaseous CO2 stream.

57. The system of claim 56, wherein the gaseous CO2 stream has a CO2 concentration of between about 2% to about 40% CO2 by volume.

58. The system of claim 57, wherein the gaseous CO2 stream has a CO2 concentration of between about 3.7% and about 20% by volume.

59. The system of any one of claims 56 to 58, wherein the gaseous CO2 stream has a temperature of about 70 °C or less. 51sf-625386234037-20002.40 60. The system of any one of claims 56 to 59, further comprising a blower unit configured to output air, wherein the reactor is configured to receive the air, and a second gaseous outlet configured to output the air.

61. The system of claim 60, further comprising a first heater unit, wherein the first heater unit is in-line with the blower unit and is configured to heat the air.

62. The system of claim 61, wherein the air is heated to between about 110 °C and about 200 °C.

63. The system of any one of claims 56 to 62, further comprising a carrier source configured to output a carrier gas, and wherein the reactor is configured to receive the carrier gas, wherein the carrier gas contacts the sorbent composition, and a CO2 outlet configured to discharge an enriched CO2 stream, wherein the enriched CO2 stream comprises a higher concentration of CO2 than the gaseous CO2 stream.

64. The system of claim 63, wherein the carrier gas is gaseous CO2, steam, or a combination thereof.

65. The system of claim 63, further comprising a second heater unit, wherein the second heater unit is in-line with the carrier source and is configured to heat the carrier gas.

66. The system of claim 64, wherein the carrier gas is heated to between about 120 °C. and 200 °C.

67. The system of any one of claims 63 to 65, further comprising a heat exchanger and a CO2 outlet, wherein the heat exchanger is configured to receive the carrier gas and the enriched CO2 stream from the reactor and to condense the carrier gas, and wherein the CO2 outlet is configured to receive the enriched CO2 stream from the heat exchanger and discharge the CO2 enriched stream.

68. The system of any one of claims 63 to 67, wherein the enriched CO2 stream has a CO2 concentration of between about 10% and about 99% by volume.

69. The system of claim 68, wherein the enriched CO2 stream has a CO2 concentration of at least about 80% by volume.

70. The system of any one of claims 67 to 69, wherein the heat exchanger is further configured to cool the reactor.

71. A method of capturing CO2, comprising contacting a gaseous CO2 stream with a sorbent composition of any one of claims 1 to 39. 52sf-625386234037-20002.40 72. The method of claim 71, further comprising heating the sorbent composition.

73. The method of claim 72, further comprising regenerating the sorbent composition to produce a gaseous stream comprising a higher concentration of CO2 than the gaseous CO2 stream.

74. The method of claim 73, further comprising drying the sorbent composition.

75. The method of claim 74, further comprising cooling the sorbent composition.

76. The method of any one of claims 71 to 73, wherein the sorbent composition is in a reactor.

77. The method of any one of claims 71 to 74, wherein the active component for CO2 chemisorption is one or more metal carbonates.

78. The method of claim 77, wherein the at least one metal carbonate is in the form of a stable hydrate. 53sf-6253862