Isolation of carbon dioxide using halogen gases

Abstract

A method for isolating carbon dioxide is disclosed. The method includes providing a container with a first chamber and a second chamber separated by a cation exchange membrane, providing a first solution in the first chamber that includes a metal carbonate, providing a second solution in the second chamber that includes an acid, acidifying the first solution by allowing protons from the second solution to pass through the cation exchange membrane, forming salts in the second solution by allowing metal ions from the first solution to pass through the cation exchange membrane, and isolating carbon dioxide. An apparatus for isolating carbon dioxide is also disclosed.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 313,044, filed February 23, 2022, U.S. Provisional Application No. 63 / 319,163, filed March 11, 2022, and U.S. Provisional Application No. 63 / 326,584, filed April 1, 2022, which are incorporated by reference herein in their entireties.

[0002] Technical Field The subject matter described herein relates to an apparatus and method for isolating carbon dioxide using halogens. [Background technology]

[0003] background The combined production of cement and steel accounts for around 15% of global anthropogenic CO2 emissions. The cement industry releases more than 2 billion tonnes of carbon dioxide into the air each year to manufacture the ubiquitous building material.

[0004] We need to either decarbonize the cement industry to achieve a net-zero emissions economy, or find solutions to remove CO2 directly from the air. Summary of the Invention [Means for solving the problem]

[0005] A quick overview In summary, the present disclosure provides methods, systems, and apparatus for isolating carbon dioxide from metal carbonates or air.

[0006] A reactor for isolating carbon dioxide is disclosed. The reactor comprises a vessel separated into a first chamber and a second chamber by an ion exchange membrane, the vessel (100) being filled with water and the second chamber receiving a halogenated gas. The reactor further comprises a first inlet fluidly connected to a body of the first chamber, the first inlet receiving a metal carbonate. The reactor further comprises a first outlet fluidly connected to a lower portion of the first chamber, the first outlet configured to collect a solid residue. The reactor further comprises a second outlet fluidly connected to the lower portion of the second chamber. The reactor further comprises a first gas outlet fluidly connected to an upper portion of the first chamber, the first gas outlet releasing carbon dioxide.

[0007] An apparatus for isolating carbon dioxide is disclosed. The apparatus comprises a first chamber containing a metal carbonate and may further comprise a salt. The apparatus further comprises a second chamber containing an acid, the second chamber being separated from the first chamber by a cation exchange membrane.

[0008] A method of isolating carbon dioxide is disclosed. The method includes providing a container with a first chamber and a second chamber separated by a cation exchange membrane. The method further includes providing a first solution in the first chamber comprising a metal carbonate. The method further includes providing a second solution in the second chamber comprising an acid. The method further includes acidifying the first solution by allowing protons from the second solution to pass through the cation exchange membrane. The method further includes forming a salt in the second solution by allowing metal ions from the first solution to pass through the cation exchange membrane. The method further includes isolating the carbon dioxide.

[0009] A method of producing calcium hydroxide is disclosed. The method includes providing a first solution comprising calcium carbonate and sodium chloride. The method further includes providing a second solution comprising aqueous chlorine. The method further includes flowing the first solution into a first chamber of a vessel comprising a cation exchange membrane separating the first chamber from the second chamber. The method further includes flowing the second solution into the second chamber. The method further includes acidifying the first solution by allowing protons from the second solution to pass through the cation exchange membrane, thereby forming a third solution comprising calcium chloride. The method further includes contacting the third solution with a fourth solution comprising sodium hydroxide to form calcium hydroxide.

[0010] A method for isolating carbon dioxide is disclosed. The method includes providing a cabin including a first space and a second space separated by a reactor with a cation exchange membrane, the first space including a first carbon dioxide. The method further includes basifying the first carbon dioxide with a first solution including NaOH to form NaHCO3 and H2O in the reactor. The method further includes providing a second solution including an acid in the reactor. The method further includes acidifying the first solution by allowing protons from the second solution to pass through the cation exchange membrane to release CO2(g). The method further includes forming salts in the second solution by allowing metal ions from the first solution to pass through the cation exchange membrane. The method further includes isolating and providing carbon dioxide to the second space.

[0011] A method of isolating carbon dioxide is disclosed. The method includes providing a vessel with a first chamber and a second chamber separated by a cation exchange membrane. The method further includes providing a first solution in the first chamber, the first solution including a metal carbonate. The method further includes providing a second solution in the second chamber, the second solution including an acid. The method further includes acidifying the first solution by allowing protons from the second solution to pass through the cation exchange membrane. The method further includes forming a salt in the second solution by allowing metal ions from the first solution to pass through the cation exchange membrane. The method further includes isolating carbon dioxide. The method further includes reacting the salt formed in the second solution with a metal oxide catalyst to form oxygen and an aqueous sodium chloride solution. The method further includes electrolyzing the aqueous sodium chloride solution to form a halogen gas and a metal base.

[0012] Various aspects and embodiments are now described more fully below. Such aspects and embodiments may take many different forms, and the illustrative ones disclosed herein are not intended to be limiting. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. [Brief description of the drawings]

[0013] [Figure 1A] FIG. 1A illustrates a metal acidification reactor according to certain embodiments of the present disclosure.

[0014] [Figure 1B] FIG. 1B shows a diagram illustrating the chemistry within a reactor according to certain embodiments of the present disclosure.

[0015] [Figure 1C] FIG. 1C shows a diagram illustrating the chemistry within the reactor according to certain embodiments of the present disclosure.

[0016] [Figure 1D]FIG. 1D shows a diagram illustrating the chemistry within the reactor according to certain embodiments of the present disclosure.

[0017] [Figure 1E] FIG. 1E shows a diagram illustrating the chemistry for producing calcium hydroxide in a reactor according to certain embodiments of the present disclosure.

[0018] [Figure 1F] FIG. 1F shows a diagram illustrating the chemistry within a reactor according to certain embodiments of the present disclosure.

[0019] [Figure 2A] FIG. 2A shows a diagram illustrating the installation of an enclosed space CO2 cryogenic capture device according to one embodiment of the present disclosure.

[0020] [Figure 2B] FIG. 2B shows a schematic diagram illustrating the flow of compounds through the components of a closed-loop CO2 cryogenic capture device according to one embodiment of the present disclosure.

[0021] [Figure 2C] FIG. 2C shows a schematic diagram illustrating the flow of compounds through the components of a closed-loop CO2 cryogenic capture device according to one embodiment of the present disclosure for the production of dry air.

[0022] [Diagram 3] FIG. 3 is a simplified flow chart illustrating a method for isolating carbon dioxide according to certain embodiments of the present disclosure.

[0023] [Figure 4] FIG. 4 is a simplified flow chart illustrating a method for producing calcium hydroxide according to certain embodiments of the present disclosure.

[0024] [Diagram 5] FIG. 5 is a simplified flow chart illustrating a method for isolating carbon dioxide in an enclosed space according to certain embodiments of the present disclosure.

[0025] [Figure 6] FIG. 6 is a simplified flow chart illustrating a carbon dioxide isolation and aqueous sodium chloride electrolysis process according to certain embodiments of the present disclosure.

[0026] [Figure 7] FIG. 7 shows a diagram illustrating the chemistry within a reactor according to certain embodiments of the present disclosure.

[0027] [Figure 8] FIG. 8 shows a diagram illustrating the chemistry within a reactor according to certain embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Detailed Description I. Definition For convenience, certain terms used in the specification, examples, and claims are collected here. Unless otherwise defined, all technical and scientific terms used in this disclosure have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0029] The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a "polymer" includes a single polymer as well as two or more of the same or different polymers, reference to an "attachment" includes a single attachment as well as two or more of the same or different attachments, and so forth.

[0030] As used herein, the terms "comprise(s)", "include(s)", "having", "has", "can", "contain(s)" and variations thereof are intended to be open-ended transitional phrases, terms or words that do not exclude additional acts or structures. The present disclosure also contemplates other embodiments that "consist of", "consist of" and "consisting essentially of" the embodiments or elements presented herein, whether or not expressly stated.

[0031] The term "about" is meant to encompass a deviation of plus or minus 5 percent, particularly with respect to a given quantity.

[0032] As used herein, the term "calcination" refers to heating solids to high temperatures to remove volatile materials, oxidize parts of the mass, or weaken them. In certain embodiments of the present disclosure, the term "calcination" refers to driving off CO2 from metal carbonates to produce the corresponding metal oxides. For example, and without limitation, calcination of calcium carbonate refers to the process of heating calcium carbonate to high temperatures to produce carbon dioxide and calcium oxide.

[0033] The term "clinker" or "lime clinker" as used herein refers to the product of calcium hydroxide and clay that has been processed in a kiln.

[0034] The term "Portland cement" as used herein refers to a mixture of lime clinker and small amounts of gypsum ground into a powder, as is the industry standard for cement. Portland cement is blended with water, sand, and gravel to form concrete, a rock material used to form building foundations, roads, dams, and modern infrastructure.

[0035] As used herein, the term "alumina" refers to aluminum oxide, Al2O3.

[0036] As used herein, the term "flue gas" refers to gas that leaves a fireplace, oven, furnace, boiler, or steam generator and enters the atmosphere through a flue, which is a pipe or channel for carrying exhaust gases.

[0037] As used herein, the term "flue scrubber" refers to the removal of pollutants from industrial exhaust systems.

[0038] As used herein, the term "air contactor" refers to a small device that controls the flow of electricity to one of the components of an air conditioner.

[0039] As used herein, the term "chlorine water" refers to water mixed with chlorine gas to generate HCl and HOCl as shown in equation (1). Low-temperature capture of carbon dioxide

[0040] In certain embodiments, the present disclosure provides methods and apparatus for the low temperature capture of carbon dioxide. The low temperature capture of carbon dioxide does not require a heat source to isolate the carbon dioxide. In certain embodiments, the carbon dioxide is captured from air.

[0041] In certain embodiments, carbon dioxide is captured from flue gas.

[0042] In certain embodiments, the process for low temperature capture of carbon dioxide is a two-step process. In certain embodiments, the first step includes a flue scrubber / air contactor with a base. In this regard, air or exhaust is collected in the flue scrubber or air contactor containing carbon dioxide that is treated with a base. In certain embodiments, the base is a water-soluble Group IA or Group IIA base. In certain specific embodiments, the base is NaOH.

[0043] In certain embodiments, carbon dioxide from the air and / or flue gas reacts with a base to form a metal carbonate. In certain specific embodiments, the metal carbonate is NaHCO3, Na2CO3, or a mixture thereof. The resulting metal carbonate solution can be stored or processed as further described in the following sections. This process is illustrated in Figures 2B-2C. Isolation of carbon dioxide from metal carbonates

[0044] In certain embodiments, the present disclosure provides methods and apparatus for isolating carbon dioxide.

[0045] In certain embodiments, carbon dioxide is isolated from the metal carbonate using an acid. In certain embodiments, the metal carbonate is Li2CO3, Na2CO3, K2CO3, MgCO3, CaCO3, SrCO3, FeCO3, and BaCO3. In certain embodiments, the metal of the metal carbonate is such that the metal halide is soluble and more stable in acid than the metal carbonate. In certain specific embodiments, the metal carbonate is CaCO3.

[0046] In certain embodiments, the metal carbonate is a Group IA or Group IIA metal carbonate. In certain embodiments, the metal carbonate is obtained from the reaction between a metal hydroxide and carbon dioxide as described above. In certain embodiments, the metal carbonate is Na2CO3 and is obtained from the reaction of NaOH with carbon dioxide.

[0047] In certain embodiments, carbon dioxide is released from the carbonate by reaction with an acid. In certain embodiments, the acid suitable for releasing carbon dioxide is stronger than carbonic acid. For example, an acid with a pKa of less than 6.35 in water at 25° C. is used. This avoids membrane fouling. At low pH, such as a pKa of less than 6.35, metal species are less likely to precipitate, so there was no risk of fouling when there was a substantial pH gradient across the membrane. In certain embodiments, the acid is derived from a halogen. In certain embodiments, the halogen is chlorine or bromine.

[0048] In certain specific embodiments, the acid is derived from Cl. In certain specific embodiments, the acid is derived from the reaction of water with Cl. In certain embodiments, the Cl2 used in the process of the present disclosure is obtained from brine electrolysis. If there is a low demand for acid or base, or if there is a shift between the demand for hydrogen and other products of brine electrolysis, chlorine can be in excess, making it an economical starting material.

[0049] In certain embodiments, the process for carbon dioxide isolation begins by saturating water with a halogen. For clarity and illustrative purposes, the embodiments of the present disclosure are described herein using Cl2 as the halogen. However, as will be readily understood by those skilled in the art, other halogens, including bromine, can also be used in the systems disclosed herein, and the reaction proceeds by a similar mechanism. For example, but not limited to, when the halogen is chlorine, the method includes forming chlorine water. When the halogen selected is fluorine, bromine, or iodine, fluorine water, bromine water, or iodine water is formed. The halogen water may be saturated halogen water.

[0050] Chlorine water has a pH of about 1.6. Bromine water has a pH range of 2 to 3. Cl2 can then oxidize water as shown by equation (1). Cl2+H2O→HCl+HOCl (1)

[0051] K of HCl a is 10 6 The K of HOCl a is small (10 -8 ) but the disproportionation reaction product HClO3 is 10 9 Large pK exceeding a The protons of the halogen water can further react with the metal carbonate. In certain embodiments, when the metal carbonate is calcium carbonate, CaCO, calcium bicarbonate, Ca(HCO)(aq) can be formed first, which can then be reacted with Ca 2+(aq) and carbonic acid, H2CO3. Carbonic acid then readily decomposes into water and carbon dioxide. This reaction is summarized in equation (2) below. CaCO3+2H + →Ca 2+ (aq) + H2O + CO2(g) (2)

[0052] In certain embodiments, when the metal carbonate is sodium carbonate and / or sodium bicarbonate, it is Na + (aq) and carbonic acid, H2CO3. Carbonic acid then readily decomposes to water and carbon dioxide. This reaction is similar to that shown in equation (2) with calcium carbonate. Na2CO3+2H + →2Na + (aq) + H2O + CO2(g) (3) NaHCO3+H + →Na + (aq) + H2O + CO2(g) (4)

[0053] The carbon dioxide leaves the solution as a gas and can be collected.

[0054] In certain embodiments, the halogen water remains separated from the metal carbonate solution using a cation exchange membrane. Thus, although protons can cross the membrane and react with the metal carbonate, the halogen does not pass through the cation exchange membrane, preventing it from interacting with the carbon species.

[0055] In a particular embodiment, acidification of metal carbonates such as CaCO3 can be performed using a reactor as shown in FIG. 1A. Although FIG. 1A shows an embodiment in which CaCO3 is the metal carbonate, Cl2 is the halogen, and NaCl is the salt, one skilled in the art will readily recognize that the system works similarly for other metal carbonates, halides, and salts such as Na2CO3 or NaHCO3 discussed in this application. As shown in FIG. 1A, in this embodiment, the reactor comprises a vertical tube 100 vertically divided into a first compartment 101 and a second compartment 103 by a cation exchange membrane 105. The tube is filled with water. As shown in FIG. 3, the device comprises a gas outlet 111 fluidly connected to the first chamber 101, a first liquid inlet 109 fluidly connected to the first chamber 101, a first liquid outlet 113 fluidly connected to the first chamber 101, and a second liquid outlet 115 fluidly connected to the second chamber 103.

[0056] In certain embodiments, instead of using vertical tubes 100, the tubes may be in other orientations. In certain other embodiments, instead of using vertical tubes 100, the reactor may use a flow field, such as a serpentine flow field divided by cation exchange membranes 105.

[0057] In a first step, a solution of metal carbonates, such as calcium carbonate and sodium chloride, is added to the first compartment 101. In certain embodiments, a halide gas, such as chlorine, is added to the second compartment 103 via a gas inlet 117 at the bottom of the second compartment 103 to form saturated chlorine water. In certain other embodiments, saturated chlorine water can be prepared separately and added directly to the second chamber 103. As shown in FIG. 1A, unreacted chlorine can be collected from the top of the second compartment via a gas outlet 119. The gas inlet 117 and outlet 119 are fluidly connected to allow for recycling of the unreacted halide gas.

[0058] Protons from the chlorine water can pass through the cation exchange membrane 105, thereby acidifying the metal carbonate to provide carbonic acid, which readily decomposes into water and carbon dioxide as described above. The carbon dioxide can then be removed from the reaction as a gas via gas outlet 111.

[0059] In some embodiments, salt may be added. Sodium from the added salt charge balances the protons by crossing the membrane to the second chamber to form sodium chloride (NaCl) and sodium hypochlorite (NaOCl). Sodium hypochlorite can be thermally or catalytically decomposed to produce either NaClO3 or NaCl and O2. In certain embodiments, sodium hypochlorite can be used or decomposed by certain transition metal oxide catalysts, such as molybdenum promoted manganese oxide catalysts, and can be used for bleaching or isolated as NaClO3 for rocket fuel oxidizers.

[0060] The chloride remaining in the first compartment is dissolved by metal ions, e.g., Ca 2+ In some embodiments where the metal carbonate is calcium carbonate and the halide is chloride, the overall conversion is shown by equation (5): CaCO3+Cl2+2NaCl+H2O→CaCl2+CO2(g)+NaOCl+NaCl+H2O (5)

[0061] The salt (NaCl) and residual halogen gas (Cl2) can be recycled. The salt may be used for charge balancing, or it may be omitted.

[0062] In certain embodiments, the cation exchange membrane can be Nafion, or any oxidation-resistant cation exchange membrane. In certain embodiments, a physical barrier such as glass fiber can also be used.

[0063] Cation exchange membranes are prone to react with carbon dioxide to form deposits in the membrane, known as "membrane fouling" due to the solubility properties of magnesium and calcium carbonate.2+ and Ca 2+ However, by maintaining a system pH of about 2 with the cation exchange membrane, CO3 from CO2 evolution in the membrane is prevented. 2- Mineralization damage is prevented.

[0064] In one embodiment, the reactor comprises a vessel 100 separated into a first chamber 101 and a second chamber 103 by an ion exchange membrane 105, the vessel 100 being filled with water HO and the second chamber receiving a halogenated gas. In one embodiment, the reactor further comprises a first inlet 109 fluidly connected to the body of the first chamber, the first inlet receiving the metal carbonate. In one embodiment, the reactor further comprises a first outlet 113 fluidly connected to a lower portion of the first chamber, the first outlet configured to collect the solid residue. In one embodiment, the reactor further comprises a second outlet 115 fluidly connected to a lower portion of the second chamber. In one embodiment, the reactor further comprises a first gas outlet 111 fluidly connected to an upper portion of the first chamber, the first gas outlet releasing carbon dioxide.

[0065] In some embodiments, the reactor further comprises a second gas inlet 117 fluidly connected to a lower side of the second chamber than the second outlet, the second gas inlet receiving the halogenated gas. In some embodiments, the reactor further comprises a second gas outlet 119 fluidly connected to an upper portion of the second chamber and configured to collect unreacted halogenated gas from the second gas inlet. In some embodiments, the ion exchange membrane is a cation exchange membrane. In some embodiments, the reactor vertically separates the vessel into a first chamber and a second chamber. In some embodiments, the first outlet is fluidly connected to a bottom surface of the first chamber. In some embodiments, the lower portion of the first chamber is a bottom surface of the first chamber. In some embodiments, the second outlet is fluidly connected to a bottom surface of the second chamber. In some embodiments, the lower portion of the second chamber is a bottom surface of the second chamber. In some embodiments, the first gas outlet is fluidly connected to a top surface of the first chamber. In some embodiments, the upper portion of the first chamber is a top surface of the first chamber.

[0066] In some embodiments, the reactor further comprises a second inlet fluidly connected to an upper portion of the second chamber. In some embodiments, the first inlet further receives an alkali metal salt. In some embodiments, the alkali metal salt is NaCl. In some embodiments, the metal carbonate is Li2CO3, Na2CO3, NaHCO3, K2CO3, MgCO3, CaCO3, SrCO3, FeCO3, BaCO3, or combinations thereof. In some embodiments, the metal carbonate is CaCO3, NaHCO3, Na2CO3, or combinations thereof. In some embodiments, the metal carbonate is CaCO3. In some embodiments, the metal carbonate is NaHCO3. In some embodiments, the metal carbonate is Na2CO3.

[0067] In some embodiments, the halogenated gas is F2, Cl2, Br2, I2, or a combination thereof. In some embodiments, the halogenated gas is Cl2. In some embodiments, the halogenated gas is Br2.

[0068] In some embodiments, the halogenated gas is I. In some embodiments, the halogenated gas is F.

[0069] In some embodiments, the halogenated gas from the second gas inlet reacts with water to form HCl and HOCl. The reaction of Cl2 and H2O to form HCl and HOCl is shown in equation (1) below: Cl2+H2O→HCl+HOCl (1)

[0070] In some embodiments, protons H in the second chamber dissociated from HCl and HOCl. + The protons H migrate across the ion exchange membrane into the first chamber. In some embodiments, the protons H migrate from the second chamber. + reacts with a metal carbonate to form carbon dioxide. The reaction of a metal carbonate, e.g., CaCO3, with a proton to form CO2 is shown in equation (2) below: CaCO3+2H + →Ca 2+ (aq) + H2O + CO2(g) (2)

[0071] In some embodiments, an alkali metal salt, NaCl, is added to the first chamber. NaCl salt is NaCl in water. + and Cl - In some embodiments, the alkali metal cation in the first chamber, such as Na + The alkali metal cations transferred from the first chamber pass through the ion exchange membrane to the second chamber. In some embodiments, the alkali metal cations transferred from the first chamber are converted to halide anions, such as Cl. - and hypochlorite anion OCl -to form metal halides and metal hypohalides, where the alkali metal cation Na + is the halide anion Cl formed by the reaction of Cl with HO in equation (1). - and hypochlorite anion OCl - This reaction is shown in equation (17) below: 2Na + +Cl - +OCl - →NaCl+NaOCl (17)

[0072] In some embodiments, the NaCl salt is Na + and Cl - Dissociates the cation Na + When Cl is used in the second chamber by passing through the ion exchange membrane, the remaining anions Cl in the first chamber - is the Ca formed from equation (2) 2+ This results in the formation of CaCl2, as shown in equation (18) below. 2Cl - +Ca 2+ →CaCl2(18)

[0073] In some embodiments, CaCl2 is collected at the first outlet. In some embodiments, CaCl2 is collected as a solid residue. As shown in FIG. 1A, an alkali metal salt such as NaCl is added through the first inlet 109 if desired, but note that the generation of CO2 does not require an alkali metal salt. FIG. 1B is a schematic diagram of the chemistry occurring within the first chamber 101 and the second chamber 102 separated by an ion exchange membrane 105. FIG. 1C is a general schematic diagram of the chemistry occurring within the first chamber 101 and the second chamber 102 separated by an ion exchange membrane 105. The halide gas is shown as X2. The alkaline earth metal carbonate is shown as M. 2+ CO3. Alkali metal halides are represented as M 1+Y. As discussed throughout this disclosure, in some embodiments, X is F, Cl, Br, I, or a combination thereof. In some embodiments, M 2+ Be 2+ , Mg 2+ , Ca 2+ , Sr 2+ , B.A. 2+ , Ra 2+ or a combination thereof. In some embodiments, M 1+ Li + , Na + , K + , Rb + , Cs + , Fr + , or combinations thereof. In some embodiments, Y is F, Cl, Br, I, or combinations thereof. In some embodiments, an alkali metal carbonate is used in the first chamber 101. FIG. 1D is a general schematic of the chemistry that occurs in the first chamber 101 and the second chamber 102, separated by an ion exchange membrane 105.

[0074] In one embodiment, the device includes a first chamber containing a metal carbonate and a salt. The device further includes a second chamber containing an acid, the second chamber being separated from the first chamber by a cation exchange membrane. In some embodiments, the metal carbonate is selected from the group consisting of Li2CO3, NaHCO3, Na2CO3, K2CO3, MgCO3, CaCO3, SrCO3, BaCO3, and combinations thereof. In some embodiments, the salt is NaCl. In some embodiments, the acid has a pKa of less than 6.35. In some embodiments, the acid includes water saturated with a halogen gas. In some embodiments, the halogen gas is Cl2. In some embodiments, the metal carbonate is NaHCO3. In some embodiments, the metal carbonate is CaCO3. Metal Halide Processing

[0075] In certain embodiments, after removing carbon dioxide, the reaction mixture has an aqueous metal salt. In certain embodiments, a base can be added to the aqueous metal salt to produce different compounds of interest. In certain embodiments, the resulting compounds have low solubility in water and therefore can be easily removed from the reaction mixture by filtration.

[0076] The resulting compound may, in certain embodiments, be a metal base with low water solubility. In certain embodiments, the resulting compound is Mg(OH)2, Ca(OH)2, or Sr(OH)2. In such embodiments, the aqueous metal salt may be mixed with a water soluble base. For example, the water soluble base may include a water soluble metal IA or metal IIA base.

[0077] 1A may be modified by adding a third compartment fluidly connected to the first liquid outlet 113. In certain embodiments, the aqueous metal salt produced in the first compartment 101 may be transferred to a third compartment containing a water-soluble base, such as a water-soluble metal IA or metal IIA base.

[0078] In certain specific embodiments, when the starting materials are calcium carbonate, sodium chloride, and chlorine gas, the reaction produces calcium chloride, CaCl2, as shown by equation (3). In certain embodiments, the calcium chloride solution can be mixed with a sodium hydroxide solution. This can be done using low grade straight-through unpurified chloralkali catholyte with high salt content. This reaction can result in the rapid precipitation of calcium hydroxide (Ca(OH)2), which is three orders of magnitude less soluble than calcium chloride, sodium chloride, and sodium hydroxide, as shown by equation (6). CaCl2(aq)+2NaOH(aq)→2NaCl(aq)+Ca(OH)2(s) (6)

[0079] In certain embodiments, the sodium hydroxide solution can be disposed in a third chamber fluidly connected to the first liquid outlet 113 of the first chamber 101 .

[0080] In certain embodiments, the Ca(OH)2 may be kept at low temperature or high dilution to prevent its precipitation within the cell. The Ca(OH)2(l) may flow out of the cell into another chamber before precipitating.

[0081] The calcium hydroxide provided from the reaction between CaCl2 and NaOH can then be removed by filtration. The calcium hydroxide can be used to produce Portland cement. In certain embodiments, the resulting calcium hydroxide can be mixed with salt, clay, sand and / or gravel to make cement. In certain embodiments, the resulting cement can absorb carbon dioxide from the atmosphere, making the process carbon negative. The sodium chloride produced in this reaction can then be recycled and used in a carbon dioxide isolation reaction. FIG. 1E shows the production of calcium hydroxide as shown in equation (6).

[0082] In other embodiments, a saturated solution containing the halogen can be prepared separately and provided to the second chamber 103 through an inlet fluidly connected to the second chamber 103 . Metal Halide Production

[0083] In certain embodiments, the disclosed method and apparatus can also be used to prepare metal halides. In certain embodiments, the disclosed method and apparatus can be used to prepare aluminum halides, particularly AlCl3. The metal halides, particularly AlCl3, can then be used to create the corresponding metal oxides, particularly alumina (Al2O3). In certain embodiments, bauxite is used as the starting material for alumina. Bauxite contains a mixture of hydrous aluminum oxide and aluminum hydroxide. However, one skilled in the art will recognize that other insoluble metal oxides, hydroxides, sulfates and carbonates, or mixtures thereof, can be used. A reactor with a vertical tube, having a feeder branch, and vertically divided into two compartments by a cation exchange membrane, as shown in FIG. 1A, can be used in alumina production. In certain embodiments, instead of using vertical tubes, the tubes can be in another orientation. In certain other embodiments, instead of using vertical tubes, the reactor can use a flow field, such as a serpentine flow field.

[0084] A suspension of metal oxides, hydroxides, sulfates, or carbonates and NaCl in water can react with halide water, such as chlorine water, through a cation exchange membrane. In particular, bauxite and NaCl in water can react with halide water, such as chlorine water, through a cation exchange membrane. Protons from the halide water can pass through the cation exchange membrane, thereby acidifying the metal oxides, hydroxides, sulfates, or carbonates to produce metal halides that are water soluble. The flow of protons across the membrane is carried by the Na + The bauxite may be equilibrated by the flow of water. In particular, the bauxite may be reacted with chlorine water, thereby acidifying the aluminum hydroxide and hydroxide of the suspension to produce aluminum chloride (AlCl3), which is water soluble. The metal chloride solution may then be mixed with a water soluble base, such as a water soluble metal IA or metal IIA base, thereby producing the metal hydroxide, which may be separated by filtration. In certain specific embodiments, the water soluble base is sodium hydroxide. In certain specific embodiments, the metal chloride is aluminum chloride.

[0085] In certain embodiments, sodium hydroxide can be added to a solution of aluminum chloride to produce a mixture of sodium chloride and soluble sodium aluminate, NaAlO2. AAlCl3+4NaOH→3NaCl+NaAlO2+2H2O (7)

[0086] The solution can be filtered to remove insoluble hydroxides of other metals. In certain embodiments, sodium aluminate can be converted to aluminum hydroxide by bubbling carbon dioxide through it. NNaAlO2+3H2O+CO2→2Al(OH)3+Na2CO3(8)

[0087] Alternatively, the sodium aluminate solution can be concentrated and the aluminum hydroxide precipitated from a supersaturated solution containing high purity aluminum hydroxide crystals.

[0088] In a particular embodiment, the isolated aluminum hydroxide can be converted to alumina by heating to a temperature of about 1470 K in a rotary kiln or fluid flash calciner. 2Al(OH)3 → Al2O3 + 3H2O (9)

[0089] Referring to Figures 2A-2C, an embodiment of the present disclosure solves the problem of CO2 concentration fluctuations in plant habitats. One embodiment of the present disclosure uses chlorine in a chlorine destruction reaction to isolate CO2 from gas. The production of metal halides, specifically aluminum halides, is shown in Figure IF. Isolation of carbon dioxide from air using a closed loop

[0090] One embodiment of the present disclosure contacts sodium hydroxide with cabin air 200 driven through a honeycomb contactor 202 until the exit solution is buffered to a pH of about 8 to produce sodium bicarbonate 206 and moist decarbonated air 204, the reaction shown in equation (10). While this example suggests the use of a honeycomb contactor, any suitable wet scrubber may be used. NaOH(aq)+CO2(N2+O2)→NaHCO3(aq)+H2O(N2+O2) (10)

[0091] The advantages and dissimilarities with standard chloralkali are evident in this step of one embodiment of the present disclosure: not only does the sodium hydroxide not need to be concentrated since the pH of an 8% solution (2M) is already 14, but it may also remain at or below 8% since at that point the NaHCO3 formed exceeds its solubility (~100 g / L).

[0092] The decarbonated air 204 may be wet, having picked up humidity from the contactor 202. This can be dealt with outside the reactor or inside the reactor, depending on the auxiliary resources available. The bicarbonate solution 206 is then taken to the neutralizer 208. The neutralizer 208 may have two chambers separated by a cation selective membrane that may divide it along a mirror surface. Chlorine 210 is carried to the other chamber, producing salt-free chlorine-saturated water. The chlorine water has a pH of about 1.6 due to reaction (1), and acidic protons cross the membrane into the bicarbonate chamber, yielding CO2(g) 212 by pH-dependent decomposition of carbonic acid (11): H2CO3 → H2O + CO2 (11)

[0093] The protons are charge balanced by diffusion of Na+ into the chloride chamber to give NaCl for the overall reaction (12): Cl2+H2O||2NaHCO3→NaCl+NaOCl||H2O+CO2(12)

[0094] The membrane is essential to prevent the mixing of chlorine and CO2, which can produce phosgene, chlorine dioxide, carbon tetrachloride, and other trace toxins (13): Cl2+CO2→C x Cl y O z (13)

[0095] Chlorine decomposition is completed via a recirculation loop and a chlorine scrubber 222. Sodium hypochlorite can be catalytically decomposed to sodium chloride and oxygen over d-block metal oxide spinels 224, particularly of copper, nickel, and cobalt (14): 2NaOCl → 2NaCl + O2 (14)

[0096] This gives the overall chlorine reaction (15): 2Cl2+2H2O→4HCl+O2;ΔH=-114kJ / mol (15)

[0097] Since both sides are four electron processes, this is coulombically equivalent to fresh water electrolysis, but retains its value in acid. The heat of reaction is available for work, since it is released upon catalysis and can be used to regenerate the silica desiccant, either within the system for the production of dry gas 228 (Figure 2C) via air drying unit 226, or external to the system if desired. The oxygen produced can pass through the final scrub (16): O2+Cl2+2NaOH→O2+NaOCl+H2O (16)

[0098] After a final scrub, the sodium hypochlorite may be decomposed into sodium chloride and oxygen as described in reaction (14). The sodium chloride solution 214 may then be electrolyzed to produce chlorine 216 and hydrogen gas 218. The chlorine gas 216 and sodium hydroxide 220 produced from the brine electrolysis 214 may then be used as inputs to reactions (10) and (12), thus providing a method for indefinitely purifying CO2 from cabin air.

[0099] An embodiment of the present disclosure can carry out each reaction simultaneously in a fluidized reactor that can be easily automated and operate with only 46% more power consumption than a single step of water electrolysis, but most of this energy is available to work through the decomposition of hypochlorite. Considering the all-in efficiency, an embodiment of the present disclosure should be approximately twice as efficient as the existing state of the art. A Bosch reactor can also be included to use the excess products of an embodiment of the present disclosure to return water and humic carbon to the soil.

[0100] The low temperature pure CO2 stream from one embodiment of the present disclosure is a significant advance over plug flow or thermal swing DACs.

[0101] In some embodiments, the cabin is an enclosed space. For example, the enclosed space is a room, an aircraft cabin, or a spacecraft cabin. In some embodiments, the reactor is mounted between the first space and the second space, as illustrated in FIG. 2A.

[0102] Referring now to FIG. 3, in one embodiment, a method of isolating carbon dioxide is disclosed. The method includes providing (301) a vessel comprising a first chamber and a second chamber separated by a cation exchange membrane. The method further includes providing (302) a first solution in the first chamber comprising a metal carbonate. The method further includes providing (303) a second solution in the second chamber comprising an acid. The method further includes acidifying (304) the first solution by allowing protons from the second solution to pass through the cation exchange membrane. The method further includes forming a salt in the second solution by allowing (305) metal ions from the first solution to pass through the cation exchange membrane. The method further includes isolating (306) the carbon dioxide.

[0103] In some embodiments, the first solution further comprises a salt. In some embodiments, the metal carbonate is prepared by contacting the carbon dioxide-containing gas with a metal base. In some embodiments, the metal carbonate is selected from the group consisting of Li2CO3, NaHCO3, Na2CO3, K2CO3, MgCO3, CaCO3, SrCO3, BaCO3, and combinations thereof. In some embodiments, the metal carbonate is NaHCO3. In some embodiments, the metal carbonate is CaCO3. In some embodiments, the metal base is NaOH. In some embodiments, the salt is sodium chloride. In some embodiments, the acid has a pKa less than 6.35. In some embodiments, the acid has a pKa less than 6.0. In some embodiments, the acid has a pKa less than 5.0. In some embodiments, the acid has a pKa less than 3.0. In some embodiments, the acid comprises water saturated with a halogen. In some embodiments, the halogen is selected from the group consisting of fluoride, chlorine, bromine, iodine, and combinations thereof. In some embodiments, the halogen is chlorine or bromine. In some embodiments, the cation exchange membrane is Nafion. In some embodiments, the method further comprises adding a water-soluble metal IA or metal IIA base to the metal halide produced in the first chamber to produce a metal hydroxide selected from the group consisting of magnesium hydroxide, calcium hydroxide, and strontium hydroxide. In some embodiments, the metal hydroxide is calcium hydroxide. In some embodiments, the method further comprises isolating the calcium hydroxide by filtration and using it to make clinker or Portland cement.

[0104] Referring now to FIG. 4, in one embodiment, a method of producing calcium hydroxide is disclosed. The method includes providing a first solution (401) comprising calcium carbonate and sodium chloride. The method further includes providing a second solution comprising aqueous chlorine (402). The method further includes flowing the first solution into a first chamber of a vessel comprising a cation exchange membrane separating the first chamber from the second chamber (403). The method further includes flowing the second solution into the second chamber (404). The method further includes acidifying the first solution by allowing protons from the second solution to pass through the cation exchange membrane, thereby forming a third solution comprising calcium chloride (405). The method further includes contacting the third solution with a fourth solution comprising sodium hydroxide to form calcium hydroxide (406).

[0105] In some embodiments, the third solution flows into a third chamber fluidly connected to the first chamber, and the third chamber contains a fourth solution. In some embodiments, aqueous chlorine is prepared by flowing chlorine gas through a second gas inlet fluidly connected to the second chamber, and any unreacted chlorine gas is collected through a second has outlet fluidly connected to the second chamber, and the second gas inlet and the second gas outlet are connected through a loop, thereby allowing recycling of unreacted chlorine gas. In some embodiments, the method further comprises producing clinker by mixing clay with calcium hydroxide. In some embodiments, the ion exchange membrane is an anion exchange membrane instead of a cation exchange membrane.

[0106] Now referring to FIG. 5, in one embodiment, a method for isolating carbon dioxide from air is disclosed. The method includes providing (501) a cabin including a first space and a second space separated by a reactor with a cation exchange membrane, the first space including a first carbon dioxide. The method further includes (502) basifying the first carbon dioxide with a first solution including NaOH to form NaHCO3 and H2O in the reactor. The method further includes (503) providing a second solution including an acid in the reactor. The method further includes (504) acidifying the first solution by allowing protons from the second solution to pass through the cation exchange membrane to release CO2(g). The method further includes (505) forming salts in the second solution by allowing metal ions from the first solution to pass through the cation exchange membrane. The method further includes (506) isolating and providing carbon dioxide to the second space. The method may further include electrolyzing salt water.

[0107] In some embodiments, the acid has a pKa less than 6.35. In some embodiments, the acid has a pKa less than 6.0. In some embodiments, the acid has a pKa less than 5.0. In some embodiments, the acid has a pKa less than 3.0. In some embodiments, the acid comprises water saturated with a halogen. In some embodiments, the halogen is selected from the group consisting of fluoride, chlorine, bromine, iodine, and combinations thereof. In some embodiments, the halogen is chlorine or bromine. In some embodiments, the cation exchange membrane is Nafion.

[0108] Referring now to FIG. 6, in one embodiment, a method of isolating carbon dioxide is disclosed. The method includes providing (601) a vessel comprising a first chamber and a second chamber separated by a cation exchange membrane. The method further includes providing (602) a first solution in the first chamber comprising a metal carbonate. The method further includes providing (603) a second solution in the second chamber comprising an acid. The method further includes acidifying (604) the first solution by allowing protons from the second solution to pass through the cation exchange membrane. The method further includes forming (605) a salt in the second solution by allowing (605) a metal ion from the first solution to pass through the cation exchange membrane. The method further includes isolating (606) the carbon dioxide. The method further includes reacting (608) the salt formed in the second solution with a metal oxide catalyst to form oxygen and an aqueous sodium chloride solution. The method further includes electrolyzing (610) the aqueous sodium chloride solution to form a halogen gas and a metal base.

[0109] Now referring to FIG. 7, in one embodiment, a three-cell reactor is disclosed. The reactor comprises a first chamber 701, a second chamber 702, and a third chamber 703. The first chamber is separated from the second chamber by an ion exchange membrane 704, which may be an anion exchange membrane. The second chamber is separated from the third chamber by an ion exchange membrane 705, which may be a cation exchange membrane. A metal carbonate aqueous solution may be flowed into the first chamber 701. A salt aqueous solution, such as a metal halide salt solution, a metal sulfate solution, a metal nitrate solution, etc., may be flowed into the second chamber 702. The third chamber 703 may be filled with water. A halogen gas, such as chlorine gas, may pass through the third chamber 703 to form halogen water. In another embodiment, halogen water is flowed into the third chamber 703.

[0110] 8, in one embodiment, a three-cell reactor is disclosed. The reactor comprises a first chamber 801, a second chamber 802, and a third chamber 803. The first chamber is separated from the second chamber by an ion exchange membrane 804, which may be a cation exchange membrane. The second chamber is separated from the third chamber by an ion exchange membrane 805, which may be a cation exchange membrane. The second chamber 802 may include an anode 806. The third chamber 803 may include a cathode 807.

[0111] An aqueous metal carbonate solution, such as calcium carbonate, may be flowed into the first chamber 801. An aqueous salt solution, such as a sodium chloride solution, may be flowed into the first chamber 801. The third chamber 803 may be filled with water.

[0112] Water can be reduced at the cathode 807 to form hydrogen gas and hydroxides. Water can be reduced to oxygen gas and H + The hydrolysis of water can be oxidized to H, which reacts with carbonates to form carbon dioxide and water. + may drive the formation of metal halides such as calcium chloride from metal carbonates such as calcium carbonate.

[0113] Although the subject matter of the present disclosure and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosed subject matter. Moreover, the scope of the present application is not intended to be limited to the specific embodiments of the process, machine, manufacture, and composition of matter, method and process described herein. Those skilled in the art will readily appreciate from the disclosed subject matter that currently existing or hereafter developed subject matter of the present disclosure, processes, machines, manufacture, compositions of matter, methods, or steps that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein can be utilized in accordance with the subject matter of the present disclosure. Accordingly, it is intended that the appended claims include within their scope such processes, machines, manufacture, compositions of matter, methods, or steps.

[0114] While several exemplary aspects and embodiments have been described above, those skilled in the art will recognize certain modifications, permutations, additions and subcombinations thereof, and it is therefore intended that the following appended claims and the claims introduced below be interpreted as including all such modifications, permutations, additions and subcombinations as fall within their true spirit and scope.

Claims

1. Providing a container comprising a first chamber and a second chamber separated by a cation exchange membrane; providing a first solution in the first chamber, the first solution comprising a carbonate; providing a second solution in the second chamber comprising an acid formed from a halogen in water; acidifying the first solution by allowing protons from the second solution to pass through the cation exchange membrane; forming a salt in the second solution by allowing metal ions from the first solution to pass through the cation exchange membrane; and collecting carbon dioxide from the first chamber; A method comprising:

2. A container at least partially filled with water and configured to receive a halogen; an inlet fluidly connected to the vessel, the vessel configured to receive carbonate salt through the inlet; an outlet fluidly connected to the vessel, the outlet configured to collect a first target product from the vessel; a gas outlet fluidly connected to the vessel, the gas outlet configured to emit a second product of interest; A reactor comprising:

3. A reactor as described in claim 2, further comprising a divider arranged to divide the vessel into a first chamber and a second chamber.

4. A reactor as described in claim 3, wherein the first chamber is positioned to receive the carbonate through the inlet and the second chamber is positioned to receive the halogen.

5. A reactor as described in claim 4, wherein the first chamber is configured to produce the second target product, and the gas outlet is fluidly connected to the first chamber.

6. A reactor as described in claim 4, wherein the first chamber is configured to produce the first target product.

7. The reactor of claim 2, wherein the vessel is further configured to receive an alkali metal salt through an inlet.

8. An apparatus for extracting carbon dioxide, comprising: a first chamber containing at least wet carbonate; a second chamber containing an acid, said second chamber being separated from said first chamber by a barrier; An apparatus comprising:

9. The apparatus of claim 8, wherein the wet carbonate comprises one or more of Li2CO3, NaHCO3, Na2CO3, K2CO3, MgCO3, CaCO3, SrCO3 and BaCO3.

10. The method of claim 1, wherein the metal carbonate is prepared by contacting a carbon dioxide-containing gas with a base.

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