Carbon dioxide concentration device, carbon dioxide concentration system, and program

Abstract

Disclosed is a carbon dioxide concentration device which generates, from a specific solution that has absorbed carbon dioxide in a treatment gas, a gas that contains carbon dioxide at a higher concentration than the treatment gas. The carbon dioxide concentration device comprises an anode, a cathode, and an anolyte chamber which is disposed on the anode side and a catholyte chamber which is disposed on the cathode side, with an electrolyte membrane being interposed therebetween. The anolyte chamber comprises a flow path regulation part that regulates the flow path of the specific solution that is supplied into the chamber, and a frame part that surrounds the periphery of the flow path regulation part.

Description

Carbon dioxide concentration device, carbon dioxide concentration system and program

[0001] This invention relates to a carbon dioxide concentration device, a carbon dioxide concentration system, and a program.

[0002] One of the causes of global warming is the increase in emissions of greenhouse gases such as carbon dioxide. To reduce carbon dioxide emissions, technologies are being developed to separate and concentrate carbon dioxide from exhaust gases and the atmosphere.

[0003] Patent Document 1 discloses a carbon dioxide emission device comprising an anode electrode, a cathode electrode, a cation exchange membrane disposed between the anode electrode and the cathode electrode, and a power supply. The carbon dioxide emission device is configured to supply hydrogen to the anode electrode by filling the space between the anode electrode and the cation exchange membrane with a first alkaline solution in which carbon dioxide is dissolved, and filling the space between the cation exchange membrane and the cathode electrode with a second alkaline solution. The carbon dioxide emission device releases the carbon dioxide dissolved in the first alkaline solution using a hydrogen oxidation-reduction reaction and electrodialysis.

[0004] Japanese Patent Publication No. 2024-31641

[0005] In a carbon dioxide concentration apparatus, carbon dioxide is released from the solution in the anode liquid chamber through which the carbon dioxide-absorbing solution flows, generating a carbon dioxide-containing gas as a gaseous product. If the carbon dioxide-containing gas generated in the anode liquid chamber remains there, the reaction area for the carbon dioxide desorption reaction decreases, leading to a decrease in the operating efficiency of the apparatus.

[0006] This disclosure aims to provide a technology that can suppress the accumulation of carbon dioxide-containing gas in a carbon dioxide concentration device.

[0007] A carbon dioxide concentrator according to one aspect of the present disclosure is a carbon dioxide concentrator that generates a gas containing carbon dioxide at a higher concentration than the process gas from a predetermined solution that has absorbed carbon dioxide from the process gas, and comprises an anode, a cathode, an anode liquid chamber located on the anode side and a cathode liquid chamber located on the cathode side with an electrolyte membrane in between, wherein the anode liquid chamber comprises a flow path restricting section that restricts the flow path of the predetermined solution supplied into the chamber and a frame section that surrounds the flow path restricting section.

[0008] A carbon dioxide concentration system according to one aspect of the present disclosure comprises a carbon dioxide concentration device that generates a gas containing carbon dioxide at a higher concentration than the process gas from a predetermined solution that has absorbed carbon dioxide from a process gas, and a processing unit, wherein the carbon dioxide concentration device comprises an anode, a cathode, an anode liquid chamber located on the anode side and a cathode liquid chamber located on the cathode side, with an electrolyte membrane in between, wherein the processing unit acquires measurement data including the flow rate of the gas containing carbon dioxide, the flow rate of the predetermined solution and an electric current in the carbon dioxide concentration device, and derives control information for controlling at least one of the flow rate of the predetermined solution and the electric current in the carbon dioxide concentration device based on the acquired measurement data.

[0009] According to this disclosure, the accumulation of carbon dioxide-containing gas in a carbon dioxide concentration device can be suppressed.

[0010] This is a schematic diagram of a carbon dioxide concentration system. This is a cross-sectional view showing an example of the configuration of the concentration section. This is a plan view showing an example of the configuration of the anode liquid chamber. This is a block diagram showing an example of the configuration of the control device. This is an explanatory diagram illustrating the operation of the carbon dioxide concentration device. This is a flowchart showing an example of the processing procedure performed by the control device.

[0011] (1) A carbon dioxide concentrator according to one aspect of the present disclosure is a carbon dioxide concentrator that generates a gas containing carbon dioxide at a higher concentration than the process gas from a predetermined solution that has absorbed carbon dioxide from the process gas, and comprises an anode, a cathode, an anode liquid chamber located on the anode side and a cathode liquid chamber located on the cathode side with an electrolyte membrane in between, wherein the anode liquid chamber comprises a flow path restricting section that restricts the flow path of the predetermined solution supplied into the chamber and a frame section that surrounds the flow path restricting section.

[0012] In the carbon dioxide concentrator of this disclosure, protons generated at the anode change the pH of a predetermined solution that has absorbed carbon dioxide, thereby causing the carbon dioxide to be removed. In addition, the voltage applied to the anode and cathode of the carbon dioxide concentrator causes predetermined ions contained in the predetermined solution to permeate the electrolyte membrane and move to the cathode liquid chamber.

[0013] In a carbon dioxide concentrator, a carbon dioxide desorption reaction occurs in the region opposite the anode, causing predetermined ions to move. If carbon dioxide-containing gas, generated as a gaseous product in the anode liquid chamber, accumulates within the chamber, the desorption reaction and the movement of predetermined ions in the region where the carbon dioxide-containing gas accumulates are hindered, leading to an increase in electrical resistance. In other words, the accumulation of carbon dioxide gas in the anode liquid chamber reduces the reaction area, causing the operating voltage of the carbon dioxide concentrator to rise.

[0014] According to the carbon dioxide concentration apparatus described in (1) above, the flow of a predetermined solution in the anode liquid chamber is restricted by the flow path restrictor, thereby creating appropriate turbulence in the flow of the predetermined solution, and thus suppressing the accumulation of carbon dioxide-containing gas in the anode liquid chamber. For example, compared to a case where the predetermined solution flows smoothly inside the anode liquid chamber without a flow path restrictor, such as a liquid chamber which is a single space partitioned from the outside, it is presumed that when turbulence is created in the flow of the predetermined solution in the anode liquid chamber by the flow path restrictor, the adhesion and accumulation of carbon dioxide gas in the anode liquid chamber can be suppressed, and the carbon dioxide gas present in the anode liquid chamber can be effectively pushed out. As a result, the reduction in the reaction area where the carbon dioxide desorption reaction occurs can be suppressed, and the decrease in the operating efficiency of the apparatus can be suppressed.

[0015] (2) In the carbon dioxide concentration apparatus described in (1) above, the flow path restricting section may include a mesh member.

[0016] According to the above configuration, when a predetermined solution flows through the anode liquid chamber, turbulence is generated by collisions between the predetermined solution and the mesh member, which can hinder the smooth flow of the fluid, thus further suppressing the accumulation of carbon dioxide-containing gas.

[0017] (3) In the carbon dioxide concentration apparatus of (1) or (2) above, the mesh of the mesh member upstream of the flow of the predetermined solution may be finer than the mesh of the mesh member downstream of the flow of the predetermined solution.

[0018] With the above configuration, the predetermined solution can be flowed downstream of the anode liquid chamber while sufficient turbulence is generated upstream of the flow of the predetermined solution by the fine mesh mesh member. Downstream of the flow, the predetermined solution can be reliably flowed toward the outlet while maintaining the flow turbulence.

[0019] (4) In any one of the carbon dioxide concentrators described in (1) to (3) above, the anode liquid chamber may include a supply port for supplying the predetermined solution, a discharge port for discharging the predetermined solution, and a plurality of flow paths provided between the supply port and the flow path restricting section and between the discharge port and the flow path restricting section.

[0020] With the above configuration, a predetermined solution can be delivered to the flow path regulating section through multiple flow paths, allowing the fluid to be reduced or divided into smaller streams, thereby improving the flow path regulating effect.

[0021] (5) In any one of the carbon dioxide concentration apparatuses described in (1) to (4) above, one of the plurality of flow paths may be connected to the vicinity of one end of one side of the rectangular flow path restricting section.

[0022] With the above configuration, fluid can be reliably supplied to the ends of the flow restriction section. By evenly supplying the predetermined solution throughout the entire flow restriction section, the accumulation of carbon dioxide-containing gas can be further suppressed.

[0023] (6) In any one of the carbon dioxide concentration devices according to (1) to (5) above, the frame portion may be formed of an elastic material.

[0024] According to the above configuration, when the anode liquid chamber and other elements are laminated, the adhesion with other elements can be enhanced, and leakage of liquid and gas from the anode liquid chamber and inflow into the anode liquid chamber can be suppressed.

[0025] (7) Any one of the carbon dioxide concentration devices according to (1) to (6) above may include an absorption unit that causes carbon dioxide in the treatment gas to be absorbed by the predetermined solution.

[0026] According to the above configuration, the carbon dioxide concentration device can continuously execute the process from absorption to concentration of carbon dioxide, improving productivity.

[0027] (8) Any one of the carbon dioxide concentration devices according to (1) to (7) above may include a gas-liquid separation unit that separates the gas containing carbon dioxide generated from the predetermined solution and the predetermined solution from each other.

[0028] According to the above configuration, the carbon dioxide-containing gas generated from the predetermined solution and the predetermined solution can be appropriately separated and recovered.

[0029] (9) Any one of the carbon dioxide concentration devices according to (1) to (8) above may include a polymer membrane having an ion exchange group between the anode and the anode liquid chamber.

[0030] According to the above configuration, leakage of the solution supplied to the anode liquid chamber to the anode can be suppressed, enabling efficient operation of the carbon dioxide concentration device.

[0031] (10) In the carbon dioxide concentration device according to (9) above, the polymer membrane may be constituted by a cation exchange membrane.

[0032] According to the above configuration, while maintaining the movement of protons generated at the anode to the anode liquid chamber, leakage of the solution supplied to the anode liquid chamber to the anode can be suppressed, enabling more efficient operation of the carbon dioxide concentration device.

[0033] (11) In the carbon dioxide concentrator described in (10) above, the electrolyte membrane may be composed of a cation exchange membrane.

[0034] According to the above configuration, cation exchange membranes are provided on both sides of the anode liquid chamber in the stacking direction. This makes it easier for predetermined ions generated by the carbon dioxide desorption reaction in the anode liquid chamber to move to the cathode liquid chamber, thus enabling more efficient operation of the carbon dioxide concentration device.

[0035] (12) A carbon dioxide concentration system according to one aspect of the present disclosure comprises a carbon dioxide concentration device that generates a gas containing carbon dioxide at a higher concentration than the process gas from a predetermined solution that has absorbed carbon dioxide from a process gas, and a processing unit, wherein the carbon dioxide concentration device comprises an anode, a cathode, an anode liquid chamber located on the anode side and a cathode liquid chamber located on the cathode side with an electrolyte membrane in between, and the processing unit acquires measurement data including the flow rate of the gas containing carbon dioxide in the carbon dioxide concentration device, the flow rate of the predetermined solution and an electric current, and derives control information for controlling at least one of the flow rate of the predetermined solution and the electric current in the carbon dioxide concentration device based on the acquired measurement data.

[0036] (13) A program according to one aspect of the present disclosure is a program that causes a computer to perform processing relating to a carbon dioxide concentrator that generates a gas containing carbon dioxide at a higher concentration than the processing gas from a predetermined solution that has absorbed carbon dioxide in a processing gas, wherein the carbon dioxide concentrator comprises an anode, a cathode, an anode liquid chamber located on the anode side and a cathode liquid chamber located on the cathode side with an electrolyte membrane in between, and causes the computer to perform processing to acquire measurement data including the flow rate of the gas containing carbon dioxide in the carbon dioxide concentrator, the flow rate of the predetermined solution and an electric current, and to derive control information for controlling at least one of the flow rate of the predetermined solution and the electric current in the carbon dioxide concentrator based on the acquired measurement data.

[0037] According to the carbon dioxide concentration system in (12) and the program in (13) above, control information can be obtained to suppress the accumulation of carbon dioxide-containing gas in the carbon dioxide concentration device.

[0038] This disclosure will be described in detail with reference to drawings illustrating embodiments thereof.

[0039] Figure 1 is a schematic diagram of the carbon dioxide concentration system 100. The carbon dioxide concentration system 100 comprises a carbon dioxide concentration device 1 and a control device 7. The carbon dioxide concentration device 1 is a device for concentrating and recovering carbon dioxide from a gas G1 containing low concentrations of carbon dioxide, which is used as a process gas (raw material gas).

[0040] The carbon dioxide concentration apparatus 1 includes an absorption tower 10, a concentration section 20, and a gas-liquid separation section 30, among other things.

[0041] The absorption tower 10 brings gas G1 and electrolyte S into gas-liquid contact to absorb carbon dioxide in gas G1 into electrolyte S. In this specification, "absorption" means dissolving into predetermined ions through a chemical reaction.

[0042] Gas G1 is a gas containing a low concentration of carbon dioxide, such as air or exhaust gas. The concentration of carbon dioxide in gas G1 is, for example, 0.01 vol% to 30 vol%. Gas G1 may also contain components other than carbon dioxide, such as nitrogen, water vapor, carbon monoxide, hydrogen sulfide, carbonyl sulfide, sulfur dioxide, nitrogen dioxide, methane, hydrogen, etc.

[0043] The absorption tower 10 comprises a main body 11 extending vertically, and a gas supply port 12, a liquid supply port 13, a first gas discharge port 14, and a first liquid discharge port 15 provided on the main body 11. The gas supply port 12 is connected to a gas supply source (not shown).

[0044] Gas G1 is supplied to the gas supply port 12. Gas G1 is supplied into the tower, flows through the tower, and is then discharged from the first gas discharge port 14. Electrolyte S for absorbing carbon dioxide is supplied to the liquid supply port 13. Electrolyte S absorbs carbon dioxide by coming into contact with gas G1 inside the tower. The electrolyte S, which has absorbed carbon dioxide, is discharged from the first liquid discharge port 15.

[0045] The method of bringing the gas G1 and the electrolyte S into contact is not particularly limited. For example, methods include bubbling the gas G1 into the electrolyte S, atomizing the electrolyte S into the gas G1 using a spray or atomizing method, or bringing high-pressure gas G1 and electrolyte S into countercurrent contact in an absorption tower 10 filled with a magnetic or metal mesh packing material.

[0046] The concentration unit 20 removes carbon dioxide from the electrolyte S that has absorbed carbon dioxide, generating gas G2 containing carbon dioxide. Gas G2 is concentrated carbon dioxide gas with a higher concentration of carbon dioxide, and contains carbon dioxide at a higher concentration than gas G1. The concentration of carbon dioxide in gas G2 is usually 90 vol% to 100 vol%.

[0047] The concentration unit 20 comprises an electrochemical cell including an anode 22, an electrolyte unit 23, and a cathode 24. The electrolyte unit 23 includes an electrolyte membrane 231, an anode liquid chamber 27, and a cathode liquid chamber 28. Electrolyte S is supplied to the anode liquid chamber 27 and the cathode liquid chamber 28.

[0048] Although Figure 1 shows two electrolyte units 23, the concentration unit 20 may be equipped with a large number of electrolyte units 23, such as 50 or 100 units, or it may be equipped with just one electrolyte unit 23.

[0049] The concentration unit 20 removes carbon dioxide from the electrolyte S that has absorbed carbon dioxide by changing the pH of the protons generated at the anode 22, and regenerates the electrolyte of the electrolyte S by selectively permeating specific ions using the electrolyte membrane 231 by electrodialysis. In this embodiment, the concentration unit 20 is an electrochemical hydrogen pump, and a configuration in which protons are generated by the oxidation-reduction reaction of hydrogen will be described.

[0050] The anode 22 of the enrichment unit 20 is supplied with gas G3 containing hydrogen. The cathode 24 generates gas G4, which is at a higher pressure than gas G3, through the hydrogen pressurization operation of the hydrogen pump. Details of the enrichment unit 20 will be described later.

[0051] The hydrogen concentration in gas G3 may be 100 vol% or less. The lower limit of the hydrogen concentration in gas G3 is not particularly limited, but may be, for example, 0.01 vol% or higher.

[0052] The gas-liquid separation unit 30 performs gas-liquid separation by means of, for example, water displacement, gravity separation, or hollow fiber membrane. A gas-liquid mixture of gas G2 discharged from the anode liquid chamber 27 and electrolyte S is supplied to the gas-liquid separation unit 30. The gas-liquid separation unit 30 separates the gas G2 and electrolyte S in the mixture, and after separation, discharges the gas G2 from the second gas outlet 301 and the electrolyte S from the second liquid outlet 302. The gas G2 discharged from the second gas outlet 301 is recovered in the carbon dioxide recovery unit 50.

[0053] Alternatively, the gas-liquid separation unit 30 may be connected to another device (not shown) and configured to supply the gas G2 discharged from the gas-liquid separation unit 30 to the other device. An example of a device to which gas G2 is supplied is an electrolytic reduction device that produces hydrocarbons (e.g., methane, ethylene, etc.) and carbon compounds such as carbon monoxide by electrolytically reducing carbon dioxide.

[0054] The carbon dioxide concentrator 1 is equipped with measuring instruments 40 for detecting the operating state of the carbon dioxide concentrator 1. The measuring instruments 40 include, for example, a liquid flow sensor 41, a gas flow sensor 42, a current sensor 43, and a voltage sensor 44 (see Figure 2).

[0055] The control device 7 is a computer that controls the operation of the carbon dioxide concentrate 1. Based on the measurement data from the measuring instrument 40, the control device 7 generates control information to control the operation of the carbon dioxide concentrate 1. The control device 7 controls the operation of the carbon dioxide concentrate 1 according to the generated control information.

[0056] Figure 2 is a cross-sectional view showing an example of the configuration of the concentration unit 20. Figure 3 is a plan view showing an example of the configuration of the anode liquid chamber 27. The configuration of the concentration unit 20 will be explained using Figures 2 and 3.

[0057] As shown in Figure 2, the concentration unit 20 has a substantially rectangular cross-section and an overall substantially rectangular parallelepiped shape. The concentration unit 20 comprises an anode plate 21 having an anode gas chamber 211, an anode 22, a plurality of electrolyte units 23, a cathode 24, a cathode plate 25 having a cathode gas chamber 251, and a power supply 26.

[0058] The anode plate 21, anode 22, multiple electrolyte units 23, cathode 24, and cathode plate 25 are arranged in this order and are fastened together, for example, by fastening members (not shown). Gaskets (not shown) may be placed between the anode plate 21 and the anode 22, and between the cathode 24 and the cathode plate 25.

[0059] Each electrolyte unit 23 comprises an electrolyte membrane 231, an anode liquid chamber 27 located on the anode 22 side via the electrolyte membrane 231, and a cathode liquid chamber 28 located on the cathode 24 side. Multiple electrolyte units 23 are stacked with an intermediate layer 29 in between, forming a laminate.

[0060] The anode plate 21 comprises an anode gas chamber 211 and a first supply port 212 into which hydrogen-containing gas G3 is supplied. The anode gas chamber 211 functions as a gas flow path for the gas G3. The anode gas chamber 211 is, for example, a groove-shaped flow path formed on the surface of the anode plate 21, and is arranged to fold back in the region of the surface of the anode plate 21 facing the anode 22. Alternatively, the anode gas chamber 211 may have multiple flow paths or branched paths. The gas G3 is supplied to the anode 22 as it passes through the anode gas chamber 211. The anode plate 21 may also have a first discharge port 213 for discharging the gas G3 that has flowed through the anode gas chamber 211.

[0061] The cathode plate 25 comprises a cathode gas chamber 251 and a second discharge port 252 for discharging hydrogen-containing gas G4. The cathode gas chamber 251 functions as a gas flow path for the gas G4. The cathode gas chamber 251 is, for example, a groove-shaped flow path formed on the surface of the cathode plate 25, and is arranged to fold back in the region of the surface of the cathode plate 25 facing the cathode 24. Alternatively, the cathode gas chamber 251 may have multiple flow paths or branched paths. The gas G4 generated in the cathode 24 is discharged from the second discharge port 252 through the cathode gas chamber 251. The gas G4 discharged from the second discharge port 252 is recovered, for example, by a hydrogen recovery unit (not shown). Alternatively, the second discharge port 252 may be connected to a first supply port 212, and the gas G4 discharged from the second discharge port 252 may be supplied to the anode 22 and used as gas G3.

[0062] The configuration of the anode plate 21 and cathode plate 25 is not limited, and for example, they may be constructed by stacking a plate member having a cathode gas chamber 251 or an anode gas chamber 211 on one side, a current collector plate, and an end plate in that order.

[0063] The anode plate 21 is electrically connected to the anode 22. The cathode plate 25 is electrically connected to the cathode 24. The anode plate 21 and the cathode plate 25 are connected to the power supply 26 via wiring.

[0064] The power supply 26 applies voltage to the anode 22 and cathode 24 via the anode plate 21 and cathode plate 25. The high-potential terminal of the power supply 26 is connected to the anode plate 21, and the low-potential terminal is connected to the cathode plate 25.

[0065] The concentration unit 20 includes a current sensor 43 for measuring the current flowing through the concentration unit 20 (electrochemical cell) and a voltage sensor 44 for measuring the voltage applied to the electrochemical cell.

[0066] The anode 22 is an electrode that generates protons from hydrogen in gas G3. The anode 22 is, for example, a gas diffusion electrode and comprises an anode catalyst layer 221 containing an anode catalyst and an anode gas diffusion layer 222. The anode catalyst layer 221 is provided on one surface of the anode gas diffusion layer 222. The anode liquid chamber 27 is in contact with the surface of the anode 22 on the anode catalyst layer 221 side, and the anode plate 21 (anode gas chamber 211) is in contact with the surface on the anode gas diffusion layer 222 side. The anode catalyst layer 221 may be formed by supporting fine particles of the anode catalyst in a highly dispersed manner on the anode gas diffusion layer 222.

[0067] Examples of anode catalysts include platinum, ruthenium, rhodium, palladium, and iridium. Anode catalysts may be used individually or in combination of two or more. When using a combination of two or more, for example, a combination containing at least platinum and ruthenium can be used.

[0068] The anode gas diffusion layer 222 is composed of a porous material and has conductivity and gas diffusion properties. Examples of the anode gas diffusion layer 222 include porous carbon fiber sheets such as carbon paper, carbon cloth, and carbon felt, and sintered bodies made of carbon particles, with carbon paper being preferred. The anode gas diffusion layer 222 may also be, for example, a sintered body of metal fibers, a sintered body of powdered metal, a metal mesh, or a foamed metal body. The metal may be, for example, a titanium alloy or stainless steel.

[0069] The cathode 24 is an electrode that generates hydrogen from protons supplied from the anode 22. The cathode 24 is, for example, a gas diffusion electrode and includes a cathode catalyst layer 241 containing a cathode catalyst and a cathode gas diffusion layer 242. The cathode catalyst layer 241 is provided on one surface of the cathode gas diffusion layer 242. The cathode liquid chamber 28 is in contact with the surface of the cathode 24 on the cathode catalyst layer 241 side, and the cathode plate 25 (cathode gas chamber 251) is in contact with the surface on the cathode gas diffusion layer 242 side. The cathode catalyst layer 241 may be formed by supporting fine particles of the cathode catalyst in a highly dispersed manner on the cathode gas diffusion layer 242.

[0070] Examples of cathode catalysts include those similar to the anode catalyst described above, and platinum is preferred. The cathode catalyst may be used alone or in combination of two or more types.

[0071] The cathode gas diffusion layer 242 is composed of a porous material and has conductivity and gas diffusivity. The material for the cathode gas diffusion layer 242 is the same as that used for the anode gas diffusion layer 222.

[0072] The method for producing the anode 22 and cathode 24 is not particularly limited. For example, they can be produced by applying a slurry of a liquid composition containing the anode catalyst or cathode catalyst to one surface of the anode gas diffusion layer 222 or the cathode gas diffusion layer 242 and drying it.

[0073] It is preferable that the anode 22 and cathode 24 are treated with a water-repellent coating. The water-repellent coating is performed, for example, by adding or laminating a water-repellent material such as polytetrafluoroethylene to the anode gas diffusion layer 222 and cathode gas diffusion layer 242, or to the anode catalyst layer 221 and cathode catalyst layer 241. By imparting water repellency to the anode 22 and cathode 24, leakage of liquid from the anode liquid chamber 27 to the anode 22 and leakage of liquid from the cathode liquid chamber 28 to the cathode 24 can be suppressed. Alternatively, leakage of liquid between them may be suppressed by providing a polymer film having ion exchange groups between the anode 22 and the anode liquid chamber 27, and between the cathode 24 and the cathode liquid chamber 28. As a polymer membrane having ion exchange groups, a cation exchange membrane (CEM) is preferred, such as Nafion (registered trademark, manufactured by DuPont), Flemion (registered trademark, manufactured by Asahi Glass Co., Ltd.), and Celemion (registered trademark, manufactured by AGC Engineering Inc.). By providing such a membrane, it is possible to suppress the movement of the liquid in the liquid chamber toward the electrode while maintaining the transfer of charge.

[0074] The electrolyte unit 23 comprises an anode liquid chamber 27, an electrolyte membrane 231, and a cathode liquid chamber 28. Each electrolyte unit 23 has the same configuration.

[0075] The electrolyte membrane 231 is a cation exchange membrane (CEM) and is composed of an electrolyte material having cation conductivity. Examples of electrolyte membranes 231 include fluorine-based cation exchange membranes such as perfluorosulfonic acid-based membranes and hydrocarbon-based cation exchange membranes. Specific examples include Nafion (registered trademark, manufactured by DuPont), Flemion (registered trademark, manufactured by Asahi Glass Co., Ltd.), and Celemion (registered trademark, manufactured by AGC Engineering Co., Ltd.).

[0076] As shown in Figures 2 and 3, the anode liquid chamber 27 is composed of a frame comprising a rectangular flat plate-shaped frame portion 272 having an opening 271 in the center, and a mesh member 273 provided in the opening 271. In the anode liquid chamber 27, the opening 271 is located between the anode catalyst layer 221 and the electrolyte membrane 231, and forms a space separated from the outside by the frame portion 272 surrounding the opening 271. The space created by the three-dimensional intersection of the mesh member 273 in the space formed by the opening 271 becomes a flow path for the electrolyte S. The anode liquid chamber 27 is arranged such that when the space is filled with the electrolyte S, the entire surface of one side of the anode catalyst layer 221, excluding the contact area with the mesh member 273, is in contact with the electrolyte S.

[0077] A third supply port 274 for supplying electrolyte S is provided at the lower part of the frame portion 272. A third discharge port 275 for discharging electrolyte S and carbon dioxide gas is provided at the upper part of the frame portion 272. The third supply port 274 and the third discharge port 275 are rectangular openings that are long in the width direction. The third supply port 274 and the third discharge port 275 are each connected to the opening 271 via a flow path 276. The third supply port 274 and the third discharge port 275 may be provided with flow paths or nozzles for connecting to passages described later.

[0078] In the anode liquid chamber 27, gas G4 and electrolyte S flow from the third supply port 274 towards the third discharge port 275. Electrolyte S, which has absorbed carbon dioxide, is supplied to the third supply port 274. As the electrolyte S flows through the opening 271 of the anode liquid chamber 27, it decarbonizes carbon dioxide. The gas-liquid mixture of gas G4 containing the decarbonized carbon dioxide and electrolyte S from which carbon dioxide has been removed flows through the anode liquid chamber 27 and is then discharged from the third discharge port 275.

[0079] The frame portion 272 is preferably made of an elastic and transparent material, such as resin or rubber. By constructing the frame portion 272 from an elastic material, the liquid-tightness and airtightness of the anode liquid chamber 27 when stacked are improved.

[0080] The thickness of the frame portion 272 is, for example, 0.3 mm to 1.5 mm, from the viewpoint of reducing electrical resistance and ensuring the flow rate of the electrolyte S.

[0081] The mesh member 273 is an example of a flow path restricting part that restricts the flow path of the electrolyte S flowing through the opening 271. By providing the mesh member 273 in the opening 271 which is the flow path of the electrolyte S, the flow of the electrolyte S in the anode liquid chamber 27 can be restricted to the space between the mesh members 273. The mesh member 273 also functions as a spacer to prevent the opening 271 from becoming blocked due to deformation of the anode catalyst layer 221 and the electrolyte membrane 231.

[0082] The mesh member 273 is formed into a rectangular shape corresponding to the shape and size of the opening 271. The mesh member 273 is, for example, a molded body woven with a plurality of vertical and horizontal wires, such that the vertical and horizontal wires intersect each other at regular intervals. The mesh member 273 is fixed to multiple locations around the periphery of the opening 271, for example, by adhesive or fusion. Multiple mesh members 273 may be provided in the thickness direction of the frame portion 272.

[0083] The material of the mesh member 273 is preferably a material that is elastic, insulating, and transparent, such as resin or rubber. The cross-sectional shape of the section perpendicular to the wire axis of the wire is not particularly limited and may be circular, elliptical, square, rectangular, etc.

[0084] The mesh size of the mesh member 273 may be appropriately set according to the size of the opening 271 and the flow rate of the electrolyte S. The mesh member 273 may have the same mesh size throughout the entire range of the opening 271, or the mesh size may change depending on the area within the opening 271. The mesh member 273 may be composed of a combination of multiple mesh members 273 with different mesh sizes.

[0085] When the mesh size is varied within the installation range of the mesh member 273, it is preferable that the mesh of the mesh member 273 provided on the upstream side of the electrolyte flow S is finer than the mesh of the mesh member 273 provided on the downstream side of the electrolyte flow S. The mesh member 273 may, for example, have a mesh size that gradually increases from one side to which a flow path 276 communicating with the third supply port 274 is connected to the other side to which a flow path 276 communicating with the third discharge port 275 is connected. Alternatively, a mesh member 273 with a relatively fine mesh may be provided at the bottom of the opening 271, and a mesh member 273 with a relatively coarse mesh may be provided at the top of the opening 271.

[0086] The flow path restricting section may be composed of a plate member, a protruding member, or the like.

[0087] The flow path 276 connecting the third supply port 274 and the third discharge port 275 to the opening 271 is, for example, a hollow flow path formed inside the frame portion 272. The cross-sectional shape of the flow path 276 may be rectangular, elliptical, or the like. Alternatively, the flow path 276 may be a groove-shaped flow path.

[0088] It is preferable that multiple flow paths 276 are provided in the width direction at each of the third supply port 274 and the third discharge port 275. When multiple flow paths 276 are provided, it is preferable that the flow path 276 at one end in the width direction is connected near the end of one side of the opening 271. Of the multiple flow paths 276, it is preferable that the flow paths 276 located at both ends are connected near both ends of one side of the opening 271. The area near the end means a certain range including the very end and its surroundings. It is preferable that each flow path 276 is arranged at a constant interval in the width direction at the third supply port 274, the third discharge port 275, and the opening 271. By forming flow paths 276 at equal intervals from one end to the other on one side of the opening 271, the electrolyte S can be flowed evenly in the width direction.

[0089] The position, size, and number of the third supply port 274, the third discharge port 275, and the flow path 276 are not limited to the example in Figure 3. For example, there may be multiple third supply ports 274 and third discharge ports 275. The third supply port 274 may be provided on the upper or side of the frame portion 272, and the third discharge port 275 may be provided on the lower or side of the frame portion 272.

[0090] The cathode liquid chamber 28 has a frame structure identical to that of the anode liquid chamber 27, and is positioned with the frame structure inverted left-right or up-down left-right. Similar to the anode liquid chamber 27, the cathode liquid chamber 28 comprises a rectangular flat frame portion 282 having an opening 281 in the center, and a mesh member 283 provided in the opening 281. A fourth supply port 284 for supplying electrolyte S is provided at the top of the frame portion 282, and a fourth discharge port 285 for discharging electrolyte S is provided at the bottom of the frame portion 282. The fourth supply port 284 and the fourth discharge port 285 and the opening 281 are connected by a plurality of flow paths 286.

[0091] In the cathode liquid chamber 28, the electrolyte S flows from the fourth supply port 284 to the fourth discharge port 285. The fourth supply port 284 is supplied with the electrolyte S from which carbon dioxide has been removed. The fourth discharge port 285 discharges the electrolyte S from which the absorbent liquid described later has been regenerated.

[0092] In this embodiment, the anode liquid chamber 27 and the cathode liquid chamber 28 use frames with the same configuration, thereby commonizing components, simplifying assembly, and reducing costs. Alternatively, the anode liquid chamber 27 and the cathode liquid chamber 28 may use separate components. If separate components are used, the frame used for the cathode liquid chamber 28 does not need to include the mesh member 283.

[0093] As shown in Figure 2, in the concentration unit 20, adjacent electrolyte units 23 and the other electrolyte unit 23 are stacked in the same orientation with an intermediate layer 29 in between. One surface of the intermediate layer 29 contacts the cathode liquid chamber 28 of one electrolyte unit 23, and the other surface of the intermediate layer 29 contacts the anode liquid chamber 27 of the other electrolyte unit 23. The intermediate layer 29 supplies protons supplied from the cathode liquid chamber 28 of one electrolyte unit 23 to the anode liquid chamber 27 of the adjacent other electrolyte unit 23.

[0094] The intermediate layer 29 includes a catalyst layer 291 containing a catalyst and a gas diffusion layer 292. The catalyst layer 291 is formed on both surfaces of the gas diffusion layer 292. The catalyst layer 291 may also be constructed by supporting fine particles of the catalyst in a highly dispersed manner on the surface of the gas diffusion layer 292.

[0095] Examples of catalysts include those similar to the anode catalyst described above, and platinum is preferred. The catalyst may be used alone or in combination of two or more types.

[0096] The gas diffusion layer 292 is made of a porous material and has electrical conductivity and gas diffusivity. The gas diffusion layer 292 uniformly diffuses hydrogen molecules supplied from the catalyst layer 291 in contact with the cathode liquid chamber 28 to the catalyst layer 291 in contact with the anode liquid chamber 27. The material constituting the gas diffusion layer 292 is the same as that of the anode gas diffusion layer 222, and is preferably carbon paper.

[0097] The method for producing the intermediate layer 29 is not particularly limited. For example, it can be produced by applying a slurry of a liquid composition containing a catalyst to the surface of the gas diffusion layer 292 and drying it.

[0098] Figure 2 shows a configuration in which electrolyte units 23 are stacked using an intermediate layer 29 having a gas diffusion layer 292 with catalyst layers 291 supported on both sides. The intermediate layer 29 only needs to be capable of supplying protons from the cathode liquid chamber 28 to the anode liquid chamber 27. The intermediate layer 29 may be, for example, a bipolar membrane formed by laminating a cation exchange membrane and an anion exchange membrane. An intermediate layer 29 using a gas diffusion layer and an intermediate layer 29 using a bipolar membrane may be used in combination.

[0099] As shown in Figure 1, the carbon dioxide concentrator 1 includes first passages 61 to fifth passages 65 that connect each component. The first passages 61 to fifth passages 65 are not particularly limited, and known piping or the like can be used as appropriate.

[0100] The first passage 61 connects the absorption tower 10 and the anode liquid chamber 27. The first passage 61 flows the electrolyte S discharged from the first liquid outlet 15 of the absorption tower 10 to the third supply port 274 of the anode liquid chamber 27. The first passage 61 branches into multiple branches at the first branching point 61a, each connected to a different anode liquid chamber 27.

[0101] The second passage 62 connects the anode liquid chamber 27 and the gas-liquid separation unit 30. The second passage 62 allows the electrolyte S and gas G4 discharged from the third discharge port 275 of the anode liquid chamber 27 to flow to the gas-liquid separation unit 30. The upstream side of the second passage 62 branches out to correspond to each anode liquid chamber 27 and merges at the first confluence point 62a.

[0102] The third passage 63 connects the gas-liquid separation unit 30 and the cathode liquid chamber 28. The third passage 63 flows the electrolyte S discharged from the second liquid discharge port 302 of the gas-liquid separation unit 30 to the fourth supply port 284 of the cathode liquid chamber 28. The third passage 63 branches into multiple branches at the second branching point 63a and connects to each cathode liquid chamber 28.

[0103] The fourth passage 64 connects the cathode liquid chamber 28 and the absorption tower 10. The fourth passage 64 flows the electrolyte S4 discharged from the fourth discharge port 285 of the cathode liquid chamber 28 to the liquid supply port 13 of the absorption tower 10. The upstream side of the fourth passage 64 branches into multiple sections corresponding to each cathode liquid chamber 28, and these branches merge at the second confluence point 64a.

[0104] The fifth passage 65 connects the gas-liquid separation unit 30 and the carbon dioxide recovery unit 50. The fifth passage 65 allows the gas G2 discharged from the second gas outlet 301 of the gas-liquid separation unit 30 to flow to the carbon dioxide recovery unit 50.

[0105] The first passage 61 and the second passage 62 are provided in the anode plate 21 and may be connected to anode supply ports and anode discharge ports (not shown) that communicate with the third supply port 274 and the third discharge port 275 of each anode liquid chamber 27. Similarly, the third passage 63 and the fourth passage 64 are provided in the cathode plate 25 and may be connected to cathode supply ports and cathode discharge ports (not shown) that communicate with the fourth supply port 284 and the fourth discharge port 285 of each cathode liquid chamber 28. In a stacked view of the anode plate 21, anode liquid chamber 27, cathode liquid chamber 28 and cathode plate 25, the anode supply ports are formed in the portion overlapping with the third supply port 274, and the anode discharge ports are formed in the portion overlapping with the third discharge port 275. In the stacked view, the cathode supply ports are formed in the portion overlapping with the fourth supply port 284, and the cathode discharge ports are formed in the portion overlapping with the fourth discharge port 285.

[0106] The absorption tower 10, anode liquid chamber 27, cathode liquid chamber 28, and the first to fourth passages 61 to 64 constitute a circulation system for the electrolyte S. Through this circulation system, the electrolyte S is recycled so that it absorbs carbon dioxide in the absorption tower 10, decarbonizes carbon dioxide in the concentration unit 20, and then absorbs carbon dioxide again in the absorption tower 10.

[0107] Pumps P1 and P2 are provided in the first passage 61 and the fourth passage 64, respectively. By driving pumps P1 and P2, the electrolyte S is delivered. Pumps for delivering the fluid may also be provided in passages other than the first passage 61 and the fourth passage 64.

[0108] A liquid flow sensor 41 for measuring the flow rate of the electrolyte S is provided in the second passage 62. The liquid flow sensors 41 may be provided between each third discharge port 275 and the first confluence point 62a, corresponding to each anode liquid chamber 27. A gas flow sensor 42 for measuring the flow rate of gas is provided in the fifth passage 65.

[0109] The measuring instrument 40, including the liquid flow sensor 41 and the gas flow sensor 42, outputs the measurement data obtained from the measurement to the control device 7. The type and mounting location of the measuring instrument 40 installed in the carbon dioxide concentration device 1 can be set as appropriate.

[0110] Figure 4 is a block diagram showing an example configuration of the control device 7. The control device 7 includes a processing unit 71, a storage unit 72, and an input / output unit 73, among others.

[0111] The processing unit 71 comprises one or more processors such as a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit). The processing unit 71 includes memory, which is a temporary storage medium such as SRAM (Static Random Access Memory) or DRAM (Dynamic Random Access Memory). The processing unit 71 may be implemented in software, or part or all of it may be implemented in hardware such as an ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array).

[0112] The storage unit 72 includes, for example, a non-volatile storage device such as a hard disk or flash memory. The storage unit 72 stores various computer programs and data that the processing unit 71 references. The storage unit 72 stores a program 721 that causes the computer to execute processing related to the generation of control information.

[0113] A computer program (program product) including program 721 may be provided on a non-temporary recording medium 7A on which the computer program is recorded in a readable format. The recording medium 7A is a portable memory such as a CD-ROM, USB memory, or SD (Secure Digital) card. The processing unit 71 reads the desired computer program from the recording medium 7A using a reading device (not shown) and stores the read computer program in the storage unit 72. Alternatively, the computer program may be provided by communication. Program 721 may be a single computer program or may consist of multiple computer programs. Program 721 may also be executed on a single computer or executed collaboratively by multiple computers.

[0114] The input / output unit 73 is equipped with an input / output interface for connecting external devices. The connection between the input / output unit 73 and the external devices may be wired or wireless. The input / output unit 73 is connected to a power supply 26, pumps P1 and P2, and measuring instruments 40, etc. The processing unit 71 acquires measurement data output from the measuring instruments 40 via the input / output unit 73 as needed. The processing unit 71 outputs control signals to the power supply 26 and pumps P1 and P2, etc., via the input / output unit 73 to control their operation.

[0115] The control device 7 may further include a communication unit for communication via a communication network, a display unit for displaying images, an operation unit for receiving user input, and so on.

[0116] The control device 7 may be located away from the carbon dioxide concentration device 1. The control device 7 may transmit and receive various information, including measurement data and control information, to and from the carbon dioxide concentration device 1 via a predetermined communication network. The control device 7 may also transmit and receive various information to and from the carbon dioxide concentration device 1 via a computer located near the carbon dioxide concentration device 1.

[0117] Figure 5 is an explanatory diagram illustrating the operation of the carbon dioxide concentrator 1. The operation of the carbon dioxide concentrator 1 will be explained using Figure 5. In the following, in order to distinguish between electrolytes S according to their composition, the electrolytes S will be referred to as electrolyte S1, electrolyte S2, and electrolyte S3 for convenience.

[0118] A gas G1 containing a low concentration of carbon dioxide is supplied to the absorption tower 10, along with an electrolyte S1. The electrolyte S1 is a solution containing an absorbent that contributes to the absorption of carbon dioxide and an electrolyte.

[0119] The absorbent solution contained in the electrolyte S1 is an alkaline aqueous solution. Examples of alkaline aqueous solutions include aqueous solutions of alkali metal compounds, alkaline earth metal compounds, and amine compounds, and an aqueous solution of an alkali metal compound is preferred.

[0120] Examples of alkali metal compounds and alkaline earth metal compounds include alkali metal compounds such as sodium, lithium, and potassium, or alkaline earth metal compounds such as calcium, magnesium, and barium. Preferably, alkali metal compounds and alkaline earth metal compounds are hydroxides, oxides, or nitrates of alkali metals or alkaline earth metals, and more preferably hydroxides. Specific examples of alkaline aqueous solutions include aqueous solutions of potassium hydroxide, sodium hydroxide, and calcium hydroxide, and preferably aqueous solutions of potassium hydroxide.

[0121] Examples of amine compounds include basic amines such as monoethanolamine, diethanolamine, diisopropanolamine, methyldiethanolamine, and triethanolamine. The alkaline aqueous solution may be used alone or in combination of two or more types.

[0122] As the electrolyte contained in the electrolytic solution S1, for example, potassium chloride, sodium chloride, etc. may be mentioned, and potassium chloride is preferable. The electrolyte may be used alone or in combination of two or more kinds.

[0123] By blending the electrolyte in the electrolytic solution S1, a reduction in the voltage required for electrodialysis can be achieved. Alternatively, the electrolytic solution S1 may not contain an electrolyte and may contain at least an absorbent solution.

[0124] In the present embodiment, it is assumed that the electrolytic solution S1 is a mixed solution (KOH - KCL solution) of potassium hydroxide and potassium chloride.

[0125] In the absorption tower 10, by the progress of the carbon dioxide absorption reaction represented by the following reaction formulas (1) and (2), the electrolytic solution S2 (KHCO 3 - KCL solution) that has absorbed carbon dioxide is obtained. In the electrolytic solution S2, carbon dioxide can form bicarbonate ions (HCO3 - ). The obtained electrolytic solution S2 is supplied to the concentration section 20. 2KOH + CO 2 → K2CO 3 + H2O... (1) K2CO 3 + H2O + CO 2 → 2KHCO 3 ... (2)

[0126] The electrolytic solution S2 may be an electrolytic solution in which KOH has completely reacted to KHCO 3 or may be an electrolytic solution that partially contains K2CO 3 which is the product of the above reaction formula (1).

[0127] In the concentration section 20, a gas G3 containing hydrogen is supplied to the anode gas chamber 211, the electrolytic solution S2 (KHCO 3 - KCL solution) that has absorbed carbon dioxide is supplied to the anode liquid chamber 27, and the electrolytic solution S3 (KCL solution) containing an electrolyte is supplied to the cathode liquid chamber 28. When a voltage is applied from the power source 26 to the anode 22 and the cathode 24, the following reaction occurs.

[0128] In the anode catalyst layer 221 of anode 22, the reaction shown in the following reaction equation (3) causes hydrogen molecules in gas G3 supplied from the anode gas chamber 211 to become protons (H + It separates into a proton (H) and an electron. + ) moves to the anode liquid chamber 27 adjacent to the anode 22. 2 →2H + +2e - ... (3)

[0129] In the anode liquid chamber 27, protons (H + In response to the movement of ) in electrolyte S2, KHCO 3 The pH of the solution decreases compared to before the oxidation reaction. Due to the decrease in pH, the chemical equilibrium in the following reaction equation (4) shifts to the right, and carbon dioxide is produced as a gaseous product. Potassium ions (K) in electrolyte S2 + ) moves through the inside of the electrolyte membrane 231 to the cathode liquid chamber 28. - +H + ⇔CO 2 +H2O...(4)

[0130] The electrolyte S2 flowing through the anode chamber 27 becomes electrolyte S3, from which carbon dioxide has been removed by the carbon dioxide desorption reaction of reaction equation (4) above, and is discharged from the anode chamber 27. Electrolyte S3 is a KCl solution mainly composed of potassium chloride. Electrolyte S3 contains potassium bicarbonate (KHCO3). 3 ) may be included.

[0131] The gas G2 containing carbon dioxide generated in the anode liquid chamber 27 and the electrolyte S3 from which the carbon dioxide has been removed flow through the anode liquid chamber 27 and are then discharged from the anode liquid chamber 27. The gas G4 is pushed by the electrolyte S3, which forms turbulence due to the mesh member 273, and flows through the anode liquid chamber 27 without accumulating there.

[0132] The mixture of gas G2 and electrolyte S3 discharged from the anode liquid chamber 27 is separated into gas and liquid in the gas-liquid separation unit 30. The separated gas G2 is recovered in the carbon dioxide recovery unit 50. The separated electrolyte S3 is supplied to the cathode liquid chamber 28. If the separated electrolyte S3 contains a large amount of unreacted electrolyte S2, the separated electrolyte S3 may be supplied back to the anode liquid chamber 27.

[0133] In the cathode liquid chamber 28, potassium ions (K) in the KCl solution within the cathode liquid chamber 28 + As the number of protons increases, + ) is supplied to the intermediate layer 29. The electrolyte S3 flowing through the cathode liquid chamber 28 contains protons (H + As the pH rises in response to the consumption of ), the absorbent solution components are regenerated to form a KOH-KCl solution, i.e., electrolyte S1. The regenerated electrolyte S1 is discharged from the cathode liquid chamber 28 and supplied again to the absorption tower 10. If the electrolyte S1 discharged from the cathode liquid chamber 28 contains a large amount of unreacted electrolyte S3, the electrolyte S1 discharged from the cathode liquid chamber 28 may be supplied back into the cathode liquid chamber 28.

[0134] In the intermediate layer 29, protons (H) adsorbed on the catalyst layer 291 on the anode 22 side + ) passes through the gas diffusion layer 292 as hydrogen molecules, and protons (H) are formed in the catalyst layer 291 on the cathode 24 side. + It is converted into a proton (H) that passes through the intermediate layer 29. + ) is supplied to the anode liquid chamber 27 of the adjacent electrolyte unit 23.

[0135] A similar reaction occurs in each electrolyte unit 23, resulting in protons (H) + The liquid moves from the anode 22 side to the cathode 24 side and is supplied to the cathode 24 from the cathode liquid chamber 28 adjacent to the cathode 24.

[0136] In the cathode catalyst layer 241 of cathode 24, hydrogen molecules are again generated by the reaction shown in the following reaction equation (5). The hydrogen generated in cathode 24 permeates through the cathode gas diffusion layer 242 and is discharged from the second discharge port 252 as gas G4 containing high-pressure hydrogen gas. Gas G4 has, for example, a hydrogen concentration of 99 vol% or more. 2H + +2e - →H 2 ... (5)

[0137] The hydrogen gas produced at cathode 24 may be hydrogen gas produced by the reduction reaction of water, as shown in the following reaction equation (6): Electrolyte S2 (KHCO 3 Hydrogen gas can be generated when water contained in the KCl solution or electrolyte S3 (KCl solution) is reduced in the cathode catalyst layer 241. 2H2O + 2e - →H2 + 2OH - ... (6)

[0138] As described above, the carbon dioxide concentrator 1 continuously absorbs and desorbs carbon dioxide by circulating an electrolyte solution, which is a mixed solution of potassium hydroxide, potassium chloride, and potassium bicarbonate. By allowing cations to permeate through the electrolyte membrane 231 and the intermediate layer 29 and regenerating the absorbent solution, the electrolyte solution S can be circulated without adding solutes during the circulation process.

[0139] In this embodiment, the carbon dioxide concentrator 1 is configured to generate protons by supplying a hydrogen-containing gas to the anode, but the carbon dioxide concentrator 1 may use other reactions, such as a water electrolysis reaction. The carbon dioxide concentrator 1 is required to include an anode that generates protons and a cathode that generates hydrogen or hydroxide ions, and to be capable of generating carbon dioxide gas from the electrolyte supplied to the anode liquid chamber 27. The gas G4 generated at the cathode 24 is not limited to being at a higher pressure than gas G3.

[0140] In the carbon dioxide concentration system 100, the operation of the carbon dioxide concentration device 1 is optimized by performing control to reduce the amount of gas G2 in the anode liquid chamber 27 based on measurement data from the carbon dioxide concentration device 1. The control information for reducing the amount of gas G2 is automatically derived by, for example, the control device 7.

[0141] The control device 7 calculates the ratio of the amount of gas G2 generated in the anode liquid chamber 27 to the amount of electrolyte S discharged from the anode liquid chamber 27, based on the flow rate of electrolyte S measured by the liquid flow sensor 41 and the flow rate of gas G2 measured by the gas flow sensor 42.

[0142] The control device 7 determines whether the calculated current proportion of gas G2 is equal to or greater than a preset threshold. If the current proportion of gas G2 is equal to or greater than the preset threshold, it generates control information to reduce the amount of gas G2 in the anode liquid chamber 27. The control device 7 may also generate control information if the difference between the current proportion of gas G2 and the threshold is equal to or greater than a preset difference threshold.

[0143] The control information includes, for example, a set value or modification value for the flow rate of the electrolyte S supplied to the anode liquid chamber 27. If the current proportion of gas G2 is above a threshold, control information is generated to increase the flow rate of the electrolyte S. The control information may also include a set value or modification value for the output of pump P2 for increasing or decreasing the flow rate of the electrolyte S. The control device 7 identifies a flow rate or a set value or modification value for the output of pump P2 to bring the current proportion of gas G2 closer to the threshold, according to the difference between the current proportion of gas G2 and the threshold.

[0144] The control information may include the set value or modification value of the current in the enrichment unit 20. If the current proportion of gas G2 is above a threshold, control information is generated to reduce the current in the enrichment unit 20 from the current value. The control device 7 identifies the set value or modification value of the current to bring the current proportion of gas G2 closer to the threshold, according to the difference between the current proportion of gas G2 and the threshold.

[0145] The control information may be generated based on the current measured by the current sensor 43. The control device 7 uses the current in the concentration unit 20 to calculate the theoretical value of the amount of gas G2 (carbon dioxide gas) generated in the anode liquid chamber 27 (g / day) using the following equation (6): Gas generation amount = (I × unit conversion coefficient / F) × gas generation efficiency × M ... (6)

[0146] In equation (6), I (A) is the electric current, the unit conversion factor (sec / day) is a coefficient for matching the units of time, F (C / mol) is the Faraday constant, the gas generation efficiency (%) is the gas generation efficiency set for carbon dioxide concentrator 1, and M (g / mol) is the molar mass of carbon dioxide. M = 44 g / mol.

[0147] The control device 7 determines whether the measured amount of gas G2 generated is equal to or greater than the calculated theoretical amount of gas G2 generated. The measured amount of gas G2 generated is calculated from the flow rate of gas G2 measured by the gas flow sensor 42. If the measured amount of gas G2 generated is equal to or greater than the theoretical value, the control device 7 generates control information to increase the flow rate of the electrolyte S or control information to decrease the current.

[0148] Figure 6 is a flowchart showing an example of a processing procedure executed by the control device 7. The following processing is performed by the processing unit 71 according to the program 721 stored in the storage unit 72 of the control device 7. The timing of the processing may be, for example, at regular intervals, or at the timing when new measurement data is measured by the measuring instrument 40.

[0149] The processing unit 71 of the control device 7 acquires measurement data including the flow rate of the electrolyte S measured by the liquid flow sensor 41, the flow rate of the gas G2 measured by the gas flow sensor 42, and the current measured by the current sensor 43 (step S1).

[0150] The processing unit 71 generates control information to control the flow rate of the electrolyte S supplied to the anode liquid chamber 27 and the current flowing through the concentration unit 20 based on the acquired current measurement data (step S2). For example, the processing unit 71 derives a set value or modification value for the flow rate, pump P2, or current to bring the current gas G2 ratio closer to the threshold value based on a comparison between the current gas G2 ratio corresponding to the flow rate of the electrolyte S and the flow rate of gas G2 and a preset threshold. Alternatively, the processing unit 71 derives a set value or modification value for the flow rate, pump P2, or current to bring the measured gas G2 ratio closer to the theoretical value based on a comparison between the theoretical value of the gas G2 generation amount corresponding to the current measured by the current sensor 43 and the actual gas G2 generation amount.

[0151] The processing unit 71 outputs a control signal corresponding to the generated control information to the carbon dioxide concentrator 1 (step S3), and ends the series of processes. The processing unit 71 may also output the generated control information to a predetermined display device and present it to the operator.

[0152] According to this embodiment, in a carbon dioxide concentrator 1 where gas is generated in the anode liquid chamber 27, the accumulation of gas in the anode liquid chamber 27 can be suppressed by the mesh member 273 provided in the anode liquid chamber 27. By generating control information regarding the flow rate and current of the electrolyte S in the carbon dioxide concentrator 1 based on measurement data from the carbon dioxide concentrator 1, the operation of the carbon dioxide concentrator 1 can be controlled to appropriately adjust the amount of gas G2 in the carbon dioxide concentrator 1, thereby further suppressing gas accumulation.

[0153] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The technical features described in each embodiment can be combined with each other, and the scope of the present invention is intended to include all modifications within the claims and equivalents thereof. The sequences shown in each embodiment are not limiting, and within a consistent scope, each processing step may be performed in a different order, and multiple processes may be performed in parallel. The processing entities for each process are not limiting, and within a consistent scope, the processing of each device may be performed by other devices.

[0154] The matters described in each embodiment can be combined with each other. Furthermore, the independent and dependent claims described in the claims can be combined with each other in any combination, regardless of the form of reference. In addition, the claims use a form in which claims referencing two or more other claims (multi-claim form), but are not limited to this. A form in which multi-claims referencing at least one multi-claim (multi-multi-claim) may also be used.

[0155] 100 Carbon Dioxide Concentration System 1 Carbon Dioxide Concentrator 10 Absorption Tower (Absorption Section) 20 Concentration Section 22 Anode 231 Electrolyte Membrane 24 Cathode 27 Anode Liquid Chamber 271 Opening 272 Frame Section 273 Mesh Member 274 Third Supply Port 275 Third Discharge Port 276 Flow Path 28 Cathode Liquid Chamber 30 Gas-Liquid Separation Section 40 Measuring Instruments 7 Control Device 71 Processing Section 72 Memory Section 73 Input / Output Section 721 Program 7A Recording Medium

Claims

1. A carbon dioxide concentrator that generates a gas containing carbon dioxide at a higher concentration than the process gas from a predetermined solution that has absorbed carbon dioxide from the process gas, comprising an anode, a cathode, an anode liquid chamber located on the anode side and a cathode liquid chamber located on the cathode side, with an electrolyte membrane in between, wherein the anode liquid chamber comprises a flow path restricting section that restricts the flow path of the predetermined solution supplied into the chamber and a frame section surrounding the flow path restricting section.

2. The carbon dioxide concentration apparatus according to claim 1, wherein the flow path restricting section comprises a mesh member.

3. The carbon dioxide concentration apparatus according to claim 2, wherein the mesh of the mesh member upstream of the flow of the predetermined solution is finer than the mesh of the mesh member downstream of the flow of the predetermined solution.

4. The carbon dioxide concentration apparatus according to claim 1 or claim 2, wherein the anode liquid chamber comprises a supply port for supplying the predetermined solution, a discharge port for discharging the predetermined solution, and a plurality of flow paths provided between the supply port and the flow path restricting section and between the discharge port and the flow path restricting section.

5. The carbon dioxide concentration apparatus according to claim 4, wherein one of the plurality of flow paths is connected near the end of one side of the rectangular flow path restricting section.

6. The carbon dioxide concentration apparatus according to claim 1 or claim 2, wherein the frame portion is formed of an elastic material.

7. The carbon dioxide concentration apparatus according to claim 1 or claim 2, further comprising an absorption unit for absorbing carbon dioxide in the processing gas into the predetermined solution.

8. The carbon dioxide concentration apparatus according to claim 1 or 2, further comprising a gas-liquid separation unit for separating the gas containing carbon dioxide generated from the predetermined solution from the predetermined solution.

9. The carbon dioxide concentration apparatus according to claim 1 or claim 2, comprising a polymer membrane having ion exchange groups between the anode and the anode liquid chamber.

10. The carbon dioxide concentration apparatus according to claim 9, wherein the polymer membrane is composed of a cation exchange membrane.

11. The carbon dioxide concentration apparatus according to claim 10, wherein the electrolyte membrane is composed of a cation exchange membrane.

12. A carbon dioxide concentration system comprising a carbon dioxide concentration device that generates a gas containing carbon dioxide at a higher concentration than the process gas from a predetermined solution that has absorbed carbon dioxide from a process gas, and a processing unit, wherein the carbon dioxide concentration device comprises an anode, a cathode, an anode liquid chamber located on the anode side and a cathode liquid chamber located on the cathode side, with an electrolyte membrane in between, and the processing unit acquires measurement data including the flow rate of the gas containing carbon dioxide in the carbon dioxide concentration device, the flow rate of the predetermined solution and an electric current, and derives control information for controlling at least one of the flow rate of the predetermined solution and the electric current in the carbon dioxide concentration device based on the acquired measurement data.

13. A program that causes a computer to perform processing relating to a carbon dioxide concentrator that generates a gas containing carbon dioxide at a higher concentration than the process gas from a predetermined solution that has absorbed carbon dioxide from the process gas, wherein the carbon dioxide concentrator comprises an anode, a cathode, an anode liquid chamber located on the anode side and a cathode liquid chamber located on the cathode side, with an electrolyte membrane in between, and the computer to perform processing to acquire measurement data including the flow rate of the gas containing carbon dioxide, the flow rate of the predetermined solution and an electric current in the carbon dioxide concentrator, and to derive control information for controlling at least one of the flow rate of the predetermined solution and the electric current in the carbon dioxide concentrator based on the acquired measurement data.

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