Electrochemical reaction device and method for operating electrochemical reaction device

Abstract

The invention relates to an electrochemical reaction device. And reduction of electrolysis efficiency is inhibited. The electrochemical reaction device is provided with an electrochemical reaction structure and a control unit, the present invention is provided with: a cathode having a reduction catalyst for promoting a reduction reaction for reducing carbon dioxide to generate a carbon compound; an anode having an oxidation catalyst for promoting an oxidation reaction for oxidizing water to generate oxygen; a separator between the cathode and the anode; a cathode flow path facing the cathode; a first flow path through which a first fluid containing carbon dioxide is supplied to the cathode flow path; a second flow path through which a second fluid containing water is supplied to the anode flow path; a third flow path through which a third fluid containing a carbon compound flows, the third flow path being discharged from the cathode flow path; a fourth flow path through which a fourth fluid containing water and oxygen flows, the fourth flow path being discharged from the anode flow path; and a gas-liquid separator which is provided midway in the anode flow path or is provided in contact with the anode flow path, and which separates a gas containing oxygen from a fifth fluid that flows through the anode flow path and contains water and oxygen.

Description

[0001] This application is based on Japanese Patent Application No. 2024-43209 (filing date: March 19, 2024), and claims the benefit of priority from the aforementioned application, the entire contents of which are incorporated herein by reference. Technical Field

[0002] Embodiments of the present invention relate to an electrochemical reaction device. Background Art

[0003] In recent years, there has been concern about the depletion of fossil fuels such as oil and coal, and expectations for renewable energy that can be utilized sustainably have risen. From the perspective of such energy problems and, in turn, environmental problems, the development of Power to Chemicals (P2C) technology has been carried out, which uses renewable energy sources such as sunlight to electrochemically reduce carbon dioxide and produce storable chemical energy. Electrochemical reaction devices such as a carbon dioxide reaction device including an electrolysis device that implements P2C technology include, for example, an anode that oxidizes water (H2O) to generate oxygen (O2) and a cathode that reduces carbon dioxide (CO2) to generate carbon compounds. The anode and cathode of the carbon dioxide reaction device are connected to a power source from renewable energy sources such as solar power generation, hydroelectric power generation, wind power generation, and geothermal power generation.

[0004] The cathode of the carbon dioxide reaction device is configured to be immersed in water containing dissolved carbon dioxide or to be in contact with carbon dioxide flowing in the flow path. The cathode reduces carbon dioxide by obtaining the reduction potential of carbon dioxide from a power source from renewable energy, thereby generating carbon compounds such as carbon monoxide (CO), formic acid (HCOOH), methanol (CH3OH), methane (CH4), ethanol (C2H5OH), ethane (C2H6), ethylene (C2H4), formaldehyde (HCHO), ethylene glycol (C2H6O2), acetic acid (CH3COOH), and propanol (C3H7OH). The anode is configured to be in contact with an electrolyte containing water, generating oxygen and hydrogen ions (H + In order to operate stably for a longer period of time in such a carbon dioxide reaction device, it is necessary to prevent the degradation of components. Summary of the Invention

[0005] A problem to be solved by the embodiments of the present invention is to suppress a decrease in electrolysis efficiency.

[0006] The electrochemical reaction device of the embodiment comprises: an electrochemical reaction structure, which includes: a cathode having a reduction catalyst that promotes a reduction reaction of reducing carbon dioxide to generate a carbon compound, an anode having an oxidation catalyst that promotes an oxidation reaction of oxidizing water to generate oxygen, a separator provided between the cathode and the anode, a cathode flow path facing the cathode, and an anode flow path facing the anode; a first flow path connected to an inlet of the cathode flow path, through which a first fluid containing carbon dioxide flows and is supplied to the cathode flow path; a first flow path connected to an inlet of the anode flow path, through which a first fluid containing carbon dioxide flows and is supplied to the anode flow path; and a second flow path in which the second fluid containing the water flows; a third flow path connected to the outlet of the cathode flow path, discharged from the cathode flow path and containing the carbon compound flows; a fourth flow path connected to the outlet of the anode flow path, discharged from the anode flow path and containing the water and the oxygen flows; and a gas-liquid separator, which is arranged in the middle of the anode flow path or in contact with the anode flow path, and separates the gas containing the oxygen from the fifth fluid by treating the fifth fluid flowing in the anode flow path and containing the water and the oxygen. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a schematic diagram showing a configuration example of the electrochemical reaction device according to the first embodiment.

[0008] Figure 2 It is a schematic diagram showing a configuration example of an electrochemical reaction device according to a second embodiment.

[0009] Figure 3 It is a schematic diagram showing a configuration example of an electrochemical reaction device according to a third embodiment.

[0010] Figure 4 It is a schematic diagram showing a configuration example of an electrochemical reaction device according to a fourth embodiment.

[0011] Figure 5 It is a schematic diagram showing a configuration example of an electrochemical reaction device according to a fifth embodiment.

[0012] Figure 6 It is a schematic diagram showing a configuration example of an electrochemical reaction device according to a sixth embodiment.

[0013] Figure 7 It is a schematic diagram showing a configuration example of an electrochemical reaction device according to a seventh embodiment.

[0014] Figure 8 It is a schematic diagram showing a configuration example of an electrochemical reaction device according to an eighth embodiment.

[0015] Figure 9 It is a schematic diagram showing a configuration example of an electrochemical reaction device according to a ninth embodiment.

[0016] Figure 10 It is a schematic diagram showing a configuration example of an electrochemical reaction device according to a tenth embodiment.

[0017] Figure 11 It is a schematic diagram showing a configuration example of an electrochemical reaction device according to an eleventh embodiment.

[0018] Figure 12 It is a schematic diagram showing a configuration example of an electrochemical reaction device according to a twelfth embodiment.

[0019] Figure 13 It is a schematic diagram showing a configuration example of an electrochemical reaction device according to a thirteenth embodiment.

[0020] Figure 14 It is a schematic diagram showing a configuration example of an electrochemical reaction device according to a fourteenth embodiment.

[0021] Figure 15 It is a schematic diagram showing a configuration example of an electrochemical reaction device according to a fourteenth embodiment.

[0022] Figure 16 Schematic diagram showing a configuration example of an electrochemical reaction device of Comparative Example 1.

[0023] Figure 17 Schematic diagram showing a configuration example of an electrochemical reaction device of Comparative Example 1.

[0024] Figure 18 Schematic diagram showing a configuration example of an electrochemical reaction device of Comparative Example 2.

[0025] (Explanation of Reference Numerals)

[0026] 1…Electrochemical reaction device, 10…Electrochemical reaction structure, 11…Cathode, 12…Anode, 13…Separator, 14…Flow path plate, 15…Flow path plate, 16…Current collector, 17…Current collector, 18…Gas-liquid separator, 18a…Gas-liquid separator, 18b…Gas-liquid separator, 19…Flow path plate, 20…Power supply, 21…Removal unit, 23…Detection unit, 25…pH adjustment unit, 26…Recovery unit, 51…Gas-liquid separator, 80…Control device, 90…Pump, 140…Cathode chamber, 150…Anode chamber, 151…Anode flow path inlet , 152…anode flow path outlet, 153…anode flow path part, 154…anode flow path part, 155…anode flow path part, 170…flow path plate, 190…cathode chamber, EC…electrochemical reaction unit, P1…flow path, P2…flow path, P2a…flow path, P2b…flow path , P3…flow path, P4…flow path, P5…flow path, P6…flow path, P7…flow path, P8…flow path, P8a…flow path, P8b…flow path, P9…flow path, P9a…flow path, P9b…flow path, P10…flow path, P10a…flow path, P10b…flow path. DETAILED DESCRIPTION

[0027] The following embodiments are described with reference to the accompanying drawings. In the various embodiments described below, substantially identical components are denoted by the same reference numerals, and their descriptions may be partially omitted. The accompanying drawings are schematic, and the relationship between thickness and planar dimensions, the ratio of thickness of various components, and the like may differ from actual results.

[0028] In addition, in this specification, "connected" includes not only direct connection but also indirect connection in some cases, unless otherwise specified.

[0029] (First embodiment)

[0030] Figure 1 It is a schematic diagram showing a configuration example of the electrochemical reaction device according to the first embodiment. Figure 1 An example of a cross-sectional structure of the electrochemical reaction device 1 is shown. The electrochemical reaction device 1 includes an electrochemical reaction structure 10, a flow path P1, a flow path P2, a flow path P3, and a flow path P4.

[0031] The electrochemical reaction structure 10 includes a cathode 11 , an anode 12 , a separator 13 , a flow channel plate 14 , a flow channel plate 15 , a current collector 16 , a current collector 17 , and a gas-liquid separator 18 .

[0032] The cathode 11 is, for example, a reduction electrode for performing a reduction reaction of at least one reduction target (a substance to be reduced). The at least one reduction target includes, for example, carbon dioxide. The cathode 11 reduces, for example, carbon dioxide supplied as a gas or carbon dioxide contained in a cathode electrolyte (cathode solution) to produce carbon compounds. Examples of carbon compounds include carbon monoxide, formic acid, methanol, methane, ethanol, ethane, ethylene, formaldehyde, ethylene glycol, acetic acid, propanol, and the like. In addition to the reduction reaction of carbon dioxide, the cathode 11 may also produce hydrogen through a side reaction by reducing water.

[0033] The cathode 11, for example, includes a reduction catalyst that promotes a reduction reaction in which carbon dioxide is reduced to form a carbon compound. The reduction catalyst can be formed, for example, using a material that reduces the activation energy for reducing the reduction target. In other words, the reduction catalyst can be formed, for example, using a material that reduces the overvoltage when the carbon dioxide reduction reaction forms a carbon compound.

[0034] The cathode 11 can be formed using, for example, a metal material or a carbon material. Examples of metal materials include metals such as gold, aluminum, copper, silver, platinum, palladium, zinc, mercury, indium, nickel, titanium, and alloys containing the metals. Examples of carbon materials include graphene, carbon nanotubes (CNT), fullerene, Ketjen black, and the like. It should be noted that the cathode 11 is not limited to these materials, and can be formed using, for example, metal complexes such as Ru complexes or Re complexes, and organic molecules having an imidazole skeleton or a pyridine skeleton. The cathode 11 can be formed using a mixture of multiple materials. For example, the cathode 11 can have a structure having a reduction catalyst in the shape of a thin film, a grid, a particle, a wire, or the like on a conductive substrate. The type of carbon compound generated by the reduction reaction also varies depending on the type of the reduction catalyst.

[0035] Anode 12 is, for example, an oxidation electrode for performing an oxidation reaction on at least one oxidation target (substance to be oxidized). The at least one oxidation target includes, for example, water. Anode 12 oxidizes the oxidation target, such as a substance or ion in the electrolyte (anode solution), to generate oxygen.

[0036] The anode 12 has, for example, an oxidation catalyst that promotes an oxidation reaction in which water is oxidized to generate oxygen. The oxidation catalyst can be formed using, for example, a material that reduces the activation energy when the oxidized object is oxidized, in other words, a material that reduces the overvoltage of the reaction. Examples of oxidation reactions at the anode 12 include oxidation of water to generate oxygen, the reaction of hydrogen peroxide, the reaction of chloride ions (Cl - ) oxidation to produce chlorine, oxidation of carbonate ions or bicarbonate ions to produce carbon dioxide, etc.

[0037] Examples of oxidation catalysts include metal materials. Examples of metal materials include ruthenium, iridium, platinum, cobalt, nickel, iron, manganese, tantalum, zirconium, etc. In addition, examples of metal materials include binary metal oxides, ternary metal oxides, quaternary metal oxides, etc. Examples of binary metal oxides include manganese oxide (Mn-O), iridium oxide (Ir-O), nickel oxide (Ni-O), cobalt oxide (Co-O), iron oxide (Fe-O), tin oxide (Sn-O), indium oxide (In-O), ruthenium oxide (Ru-O), etc. Examples of ternary metal oxides include nickel-iron oxide (Ni-Fe-O), nickel-cobalt oxide (Ni-Co-O), lanthanum-cobalt oxide (La-Co-O), nickel-lanthanum oxide (Ni-La-O), strontium-iron oxide (Sr-Fe-O), etc. As quaternary metal oxides, for example, lead-ruthenium-iridium oxide (Pb-Ru-Ir-O) and lanthanum-strontium-cobalt oxide (La-Sr-Co-O) are included. It should be noted that the oxidation catalyst is not limited to these materials, and can be formed using metal complexes such as metal hydroxides, ruthenium complexes, and iron complexes containing metals such as cobalt, nickel, iron, and manganese. In addition, the oxidation catalyst can be formed by mixing multiple materials.

[0038] Anode 12 can be formed using a composite material comprising an oxidation catalyst and a conductive material. Examples of conductive materials include carbon materials such as carbon black, activated carbon, fullerenes, carbon nanotubes, graphene, Ketjen black, and diamond; transparent conductive oxides such as indium tin oxide (ITO), zinc oxide (ZnO), fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), and antimony-doped tin oxide (ATO); metals such as copper, aluminum, titanium, nickel, silver, tungsten, cobalt, and gold; and alloys containing at least one of these metals. Anode 12 can include, for example, a structure comprising an oxidation catalyst in a thin film, lattice, particle, or linear form on a conductive substrate. The conductive substrate can be formed using, for example, a metal material comprising titanium, a titanium alloy, or stainless steel.

[0039] The diaphragm 13 is provided between the cathode 11 and the anode 12. The diaphragm 13 can separate the cathode chamber 140 from the anode chamber 150. The diaphragm 13 can allow hydrogen ions (H + ), hydroxide ions (OH - ), bicarbonate ion (HCO3 - ), carbonate ions (CO3 2- ) plasma movement. The use of the diaphragm 13 can form an electrochemical reaction unit (electrolysis unit) having a two-chamber structure. The diaphragm 13 can be placed in contact with the cathode 11 and the anode 12.

[0040] The diaphragm 13 can be formed using, for example, a membrane that allows anions or cations to selectively flow. In this way, the composition of the electrolyte in contact with the anode 12 can be made different from the composition of the electrolyte in contact with the cathode 11, and further, by utilizing differences such as differences in ionic strength and pH, the reduction reaction and the oxidation reaction can be promoted. The diaphragm 13 may have the function of allowing a portion of the ions contained in the electrolyte that immerses the cathode 11 and the anode 12 to pass through, that is, the function of shielding one or more ions contained in the electrolyte. In this way, for example, the pH and the like can be made different between the two electrolytes. In addition, with respect to the shielding of ions, a diaphragm that does not completely shield a portion of the ions but exerts an effect to the extent of limiting the amount of movement based on the ion species can be used.

[0041] The diaphragm 13 can be formed using, for example, ion exchange membranes such as Neosepta (registered trademark) from ASTOM, Selemion (registered trademark) and Aciplex (registered trademark) from Asahi Glass, Fumasep (registered trademark) and Fumapem (registered trademark) from Fumatech, Nafion (registered trademark), a fluororesin obtained by sulfonating and polymerizing tetrafluoroethylene from DuPont, Lewabrane (registered trademark) from LANXESS, IONSEP (registered trademark) from IONTECH, Mustang (registered trademark) from PALL, Ralex (registered trademark) from Mega, Gore-Tex (registered trademark) from Gore-Tex, Sustainion (registered trademark) from DIOXIDEMATERIALS, and PiperION (registered trademark) from Versogen. Ion exchange membranes can be formed using, for example, a membrane with a hydrocarbon skeleton. Anion exchange membranes can be formed using, for example, a membrane having an amine group. When there is a pH difference between the electrolyte contained in the second cathode supply fluid and the electrolyte contained in the anode supply fluid described later, the diaphragm 13 can be formed using a bipolar membrane composed of a stacked cation exchange membrane and an anion exchange membrane, thereby being able to use the electrolyte while stably maintaining the pH.

[0042] The diaphragm 13 can be formed using materials such as silicone resin, perfluoroalkoxyalkane (PFA), perfluoroethylene propylene copolymer (FEP), polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), polyethersulfone (PES), etc., a ceramic porous membrane, a filler filled with a glass filter (glass filter), agar, etc., zeolite, oxides, etc. In particular, a hydrophilic porous membrane can suppress clogging due to bubbles and is therefore preferably used as the material for the diaphragm 13.

[0043] The cathode 11, anode 12, and separator 13 are stacked to form an electrochemical reaction cell EC. The electrochemical reaction structure 10 may include a cell group formed by stacking multiple electrochemical reaction cells EC. Forming a cell group increases the amount of carbon dioxide reacted per unit area, thereby increasing the amount of carbon compounds produced. The number of stacked electrochemical reaction cells EC is preferably 10 or more and 150 or less, for example.

[0044] The flow path plate 14 has a cathode chamber 140. The cathode chamber 140 is provided on the surface of the flow path plate 14 facing the cathode 11, and is capable of forming a cathode flow path. The cathode flow path has an inlet (cathode flow path inlet) for supplying a fluid (cathode supply fluid) to the cathode chamber 140, and an outlet (cathode flow path outlet) for discharging a fluid (cathode discharge fluid) from the cathode chamber 140. The cathode supply fluid contains a gas of a reduction object. There is no particular limitation on the surface shape of the cathode flow path, and for example, it has a serpentine shape. The serpentine-shaped flow path has a plurality of return portions on the surface of the flow path plate 14 where the cathode chamber 140 is formed. There is no particular limitation on the number of the plurality of return portions. The flow path plate 14 can be formed using a conductive material such as a metal material or a carbon material.

[0045] The flow plate 15 has an anode chamber 150. The anode chamber 150 is provided on the surface of the flow plate 15 facing the anode 12, and can form an anode flow path. The anode chamber 150 is provided on the opposite side of the cathode chamber 140 of the electrochemical reaction unit EC, and is opposite to the cathode chamber 140 with the electrochemical reaction unit EC sandwiched therebetween. There is no particular limitation on the surface shape of the anode flow path, and for example, it may have a serpentine shape. The serpentine-shaped flow path has a plurality of return portions on the forming surface of the anode chamber 150 of the flow plate 15. There is no particular limitation on the number of the plurality of return portions. The flow plate 15 can be formed using conductive materials such as metal materials and carbon materials.

[0046] Current collector 16 is electrically connected to cathode 11. For example, current collector 16 is provided on the opposite side of flow plate 14 from cathode 11 and can be electrically connected to cathode 11 via flow plate 14. Current collector 17 is electrically connected to anode 12. For example, current collector 17 is provided on the opposite side of flow plate 15 from anode 12 and can be electrically connected to anode 12 via flow plate 15. Current collectors 16 and 17 can be formed using a conductive material containing a metal element such as titanium.

[0047] The current collector 16 and the current collector 17 can be connected to the power supply 20. The power supply 20 can, for example, supply electricity to the electrochemical reaction structure 10. The power supply 20 can input voltage and current for generating electrolytic reactions such as oxidation reactions and reduction reactions into the electrochemical reaction structure 10, and is electrically connected to the cathode 11 and the anode 12. The reduction reaction at the cathode 11 and the oxidation reaction at the anode 12 are carried out using the electric energy supplied from the power supply 20. The power supply 20 and the current collector 16 and the power supply 20 and the current collector 17 are connected, for example, by wiring. Electrical equipment such as an inverter, a converter, and a battery can be provided between the electrochemical reaction structure 10 and the power supply 20 as needed. The driving mode of the electrochemical reaction structure 10 can be a constant voltage mode or a constant current mode.

[0048] The power supply 20 can be a common commercial power supply, a battery, etc., or a power supply that converts renewable energy into electric energy. Examples of such power supplies include power supplies that convert kinetic energy and potential energy of wind, water, geothermal, tidal forces, etc. into electric energy, power supplies such as solar cells with photoelectric conversion elements that convert light energy into electric energy, power supplies such as fuel cells and storage batteries that convert chemical energy into electric energy, and power supplies such as devices that convert vibration energy of sound into electric energy. The photoelectric conversion element has the function of using the energy of light such as irradiated sunlight to separate charges. Examples of photoelectric conversion elements include pin junction solar cells, pn junction solar cells, amorphous silicon solar cells, multi-junction solar cells, single crystal silicon solar cells, polycrystalline silicon solar cells, dye-sensitized solar cells, organic thin film solar cells, etc. In addition, the photoelectric conversion element can be stacked with at least one of the cathode 11 and the anode 12 inside the electrochemical reaction structure 10.

[0049] The power supply 20 can, for example, adjust the current or voltage supplied to the electrochemical reaction structure 10. The power supply 20 can include, for example, a power controller that adjusts the current or voltage supplied to the electrochemical reaction structure 10. The power supply 20 can have the function of adjusting the pressure of the cathode chamber 140 or the pressure of the anode chamber 150 by adjusting the current or voltage supplied to the electrochemical reaction structure 10. The power supply 20 can be provided outside the electrochemical reaction device 1.

[0050] Flow path P1 is connected to the inlet of cathode chamber 140. Fluid supplied to cathode chamber 140 (cathode supply fluid) can flow through flow path P1. The cathode supply fluid contains carbon dioxide. The cathode supply fluid can be a gas containing gaseous carbon dioxide or an electrolyte containing carbon dioxide.

[0051] Flow path P1 can be connected to a carbon dioxide supply source. The carbon dioxide supply source may include a carbon dioxide separation and recovery device, which can be connected to the carbon dioxide separation and recovery device. The carbon dioxide gas from the carbon dioxide separation and recovery device can be supplied to flow path P1 directly or after temporary storage. Examples of carbon dioxide supply sources include, for example, thermal power plants, facilities with various incinerators and combustion furnaces such as waste incinerators, ironworks, facilities with blast furnaces, etc. The carbon dioxide supply source is not limited to these facilities, and may also be other factories that produce carbon dioxide.

[0052] Flow path P2 is connected to the anode inlet of anode chamber 150. A fluid (anode feed fluid) supplied to anode chamber 150 can flow through flow path P2. The anode feed fluid includes water or an electrolyte. Flow path P2 can be connected to an anode solution supply source. The anode solution supply source can supply, for example, an electrolyte for the anode feed fluid.

[0053] Flow path P3 is connected to the cathode outlet of cathode chamber 140. Fluid discharged from cathode chamber 140 (cathode exhaust fluid) can flow through flow path P3. Cathode exhaust fluid includes carbon compounds and hydrogen generated by the reduction reaction at cathode 11, and a portion of carbon dioxide gas or a portion of the electrolyte contained in the cathode supply fluid.

[0054] The flow path P4 is connected to the anode outlet of the anode chamber 150. The fluid discharged from the anode chamber 150 (anode exhaust fluid) can flow through the flow path P4. The anode exhaust fluid includes, for example, gaseous oxygen generated by the oxidation reaction at the anode 12, carbon dioxide transferred from the cathode chamber 140 or the electrolyte, and water or a portion of the electrolyte contained in the anode supply fluid.

[0055] The flow paths P1 , P2 , P3 , and P4 can be formed using pipes, for example.

[0056] The gas-liquid separator 18 is provided midway in the anode flow path or in contact with the anode flow path. As far as the gas-liquid separator 18 is concerned, it is possible to separate (remove) at least a portion of the gas containing oxygen from the anode fluid by treating the fluid (anode fluid) flowing in the anode flow path. The gas-liquid separator 18 is provided inside or outside the electrochemical reaction structure 10. The separated gas may include carbon dioxide that moves from the cathode chamber 140 or the electrolyte to the anode chamber 150. The gas-liquid separator 18 may be provided outside the electrochemical reaction structure.

[0057] The electrolyte solution can be a solution containing water, for example, an aqueous solution containing any electrolyte. The solution is preferably an aqueous solution that promotes the oxidation reaction of water. Examples of aqueous solutions containing electrolytes include phosphate ions (PO4 2- ), borate ion (BO3 3- ), sodium ion (Na + ), potassium ion (K + ), calcium ions (Ca 2+ ), lithium ion (Li + ), cesium ions (Cs + ), magnesium ions (Mg 2+ ), chloride ion (Cl - ), bicarbonate ion (HCO3 - ), carbonate ions (CO3 - ), hydroxide ions (OH - ) etc.

[0058] As the above-mentioned electrolyte solution, for example, a solution containing cations such as imidazolium ions and pyridinium ions and BF4 can be used. - PF6 - Salts of anions such as ethanolamine, imidazole, and pyridine, or ionic liquids that are liquid over a wide temperature range, or their aqueous solutions. Other electrolytes include solutions of amines such as ethanolamine, imidazole, and pyridine, or their aqueous solutions. Amines include primary, secondary, and tertiary amines. These electrolytes have high ion conductivity, absorb carbon dioxide, and may have properties that reduce reduction energy.

[0059] Examples of primary amines include methylamine, ethylamine, propylamine, butylamine, pentylamine, and hexylamine. Alcohols, halogens, and the like may be substituted for the amine hydrocarbons. Examples of amine hydrocarbons substituted for the amine hydrocarbons include methanolamine, ethanolamine, and chloromethylamine. Unsaturated bonds may also be present. The same applies to secondary and tertiary amines.

[0060] Examples of secondary amines include dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, dimethanolamine, diethanolamine, and dipropanolamine. The hydrocarbon used in the substitution may vary. This also applies to tertiary amines. For example, examples of amines with different hydrocarbons include methylethylamine and methylpropylamine.

[0061] Examples of the tertiary amine include trimethylamine, triethylamine, tripropylamine, tributylamine, trihexylamine, trimethanolamine, triethanolamine, tripropanolamine, tributanolamine, trihexanolamine, methyldiethylamine, and methyldipropylamine.

[0062] Examples of the cation of the ionic liquid include 1-ethyl-3-methylimidazolium ion, 1-methyl-3-propylimidazolium ion, 1-butyl-3-methylimidazolium ion, 1-methyl-3-pentylimidazolium ion, and 1-hexyl-3-methylimidazolium ion.

[0063] The 2-position of the imidazolium ion may be substituted. Examples of cations substituted at the 2-position of the imidazolium ion include 1-ethyl-2,3-dimethylimidazolium ion, 1,2-dimethyl-3-propylimidazolium ion, 1-butyl-2,3-dimethylimidazolium ion, 1,2-dimethyl-3-pentylimidazolium ion, and 1-hexyl-2,3-dimethylimidazolium ion.

[0064] Examples of the pyridinium ion include methylpyridinium, ethylpyridinium, propylpyridinium, butylpyridinium, pentylpyridinium, and hexylpyridinium. Both the imidazolium ion and the pyridinium ion may be substituted with an alkyl group and may have an unsaturated bond.

[0065] Examples of anions include fluoride ions (F - ), chloride ion (Cl - ), bromide ion (Br - ), iodide ion (I - ), BF4 - PF6 - CF3COO - CF3SO3 - 、NO3 - 、SCN - 、(CF3SO2)3C - , bis(trifluoromethoxysulfonyl)imide, bis(trifluoromethoxysulfonyl)imide, bis(perfluoroethylsulfonyl)imide, etc. Zwitterions (geminis) formed by connecting the cation and anion of the ionic liquid with a hydrocarbon can be used. A buffer solution such as a potassium phosphate solution can be supplied to the anode chamber 150 and the cathode chamber 190 described later.

[0066] The electrolyte contained in the anode supply fluid contains water as the oxidizing target. By changing the amount of water contained in the electrolyte and the electrolyte composition to change the reactivity, the selectivity of the reducing substance and the ratio of the generated substances can be changed. The electrolyte can contain a redox couple as needed. Examples of the redox couple include Fe 3+ / Fe 2+ ,IO 3- / I - wait.

[0067] Next, an example of the operation method of the electrochemical reaction device 1 is described. Here, a case in which carbon dioxide is reduced to mainly generate carbon monoxide, and water is oxidized to generate oxygen is described. If a cathode supply fluid containing carbon dioxide is supplied to the cathode chamber 140, and an anode supply fluid containing an electrolyte is supplied to the anode chamber 150, and a voltage higher than the electrolysis voltage is applied between the cathode 11 and the anode 12 by power supply from the power supply 20, an oxidation reaction of water occurs near the anode 12 in contact with the electrolyte. As shown in the following formula (1), an oxidation reaction of the water contained in the electrolyte occurs, electrons are lost, and oxygen and hydrogen ions are generated. A portion of the generated hydrogen ions moves to the cathode chamber 140 via the diaphragm 13.

[0068] 2H2O→4H + +O2+4e - …(1)

[0069] If the hydrogen ions (H + ) arrives near the cathode 11, and electrons (e - ), the reduction reaction of carbon dioxide occurs. As shown in the following formula (2), the hydrogen ions (H + ) and the electrons (e - ), reducing carbon dioxide to produce carbon monoxide.

[0070] 2CO2+4H + +4e - →2CO+2H2O…(2)

[0071] The gas components contained in the anode exhaust fluid from the anode chamber 150 are mainly oxygen as shown in the above formula (1). In the reaction between the cathode 11 and the anode 12, a large amount of carbon dioxide contained in the cathode supply fluid supplied to the cathode chamber 140 is reduced at the cathode 11, but a part of it is converted into carbon dioxide or carbonate ions (CO3 2- ), bicarbonate ion (HCO3 - ) ions flow into the anode 12 side. Regarding the carbonate ions and bicarbonate ions that migrate to the anode 12 side, if the pH of the anode solution (electrolyte) drops below, for example, 6, they exist as carbon dioxide through a chemical equilibrium reaction, and a portion dissolves in the anode solution. This carbon dioxide gas that is not completely dissolved in the anode solution is contained in the anode exhaust fluid discharged from the anode chamber 150 along with oxygen. Under typical operating conditions of the electrochemical reaction structure 10, the abundance ratio of carbon dioxide gas to oxygen in the anode exhaust fluid may rise to, for example, 2:1.

[0072] Flow path P3 can be connected to a valuable substance manufacturing device. Examples of valuable substance manufacturing devices include chemical synthesis devices that generate valuable substances by chemical synthesis using raw materials such as carbon monoxide. Examples of valuable substances include methanol obtained by a methanol manufacturing device, hydrocarbons obtained by a Fischer-Tropsch reaction device, synthetic gasoline, light oil, jet fuel, and olefin compounds obtained by an olefin manufacturing device. By arranging a valuable substance manufacturing device in the rear section of the electrochemical reaction structure 10, valuable substances with high added value can be manufactured from the products of the electrochemical reaction structure 10.

[0073] The type of chemical synthesis device is not particularly limited as long as it can react and synthesize other substances using the reduction product generated by the cathode 11. Examples of reactions using the reduction product obtained by the chemical synthesis device include chemical reactions, electrochemical reactions, and biological conversion reactions using organisms such as algae, enzymes, yeast, and bacteria.

[0074] Flow path P3 can replace the valuable substance manufacturing device and be connected to the product separator. The product separator can separate the remaining carbon dioxide from the cathode discharge fluid or remove the moisture in the cathode discharge fluid, thereby being able to separate carbon compounds such as carbon monoxide as the product. For example, when the electrochemical reaction structure 10 generates carbon monoxide gas according to the above formula (2), by using a mixed gas containing the generated carbon monoxide gas and hydrogen as a by-product of the reduction reaction as a raw material, methanol can be manufactured by methanol synthesis, or jet fuel, light oil, etc. can be manufactured by Fischer-Tropsch synthesis. It is not limited to this, and flow path P3 can replace the valuable substance manufacturing device and be connected to a tank for storing a gas containing carbon compounds such as carbon monoxide.

[0075] The cathode exhaust fluid may contain carbon dioxide, carbon monoxide, and hydrogen produced by electrolysis of water. As for the hydrogen concentration, it can be adjusted arbitrarily according to the form of use. When hydrogen is used in the chemical synthesis device, in order to use a mixture of carbon monoxide and hydrogen, carbon dioxide can be separated from the cathode exhaust fluid and used. When hydrogen is not used, only carbon monoxide is separated from the cathode exhaust fluid. When methanol is produced, the molar number of hydrogen is adjusted to about 2 times the molar number of carbon monoxide, so that the hydrogen produced at the cathode 11 can be used as a valuable substance. On the other hand, at the cathode 11, the reaction conditions can be used to suppress the side reaction of hydrogen production, and the concentration of hydrogen in the reduction product can also be adjusted within a range of 0.1% to 5% by volume. In this way, the electrochemical reaction device can be used as a carbon monoxide production device for producing high-concentration carbon monoxide.

[0076] If the electrolysis reaction of the reducing object proceeds, the reducing object, such as carbon dioxide, is converted into a reducing product, such as a carbon compound, in the cathode chamber 140. Meanwhile, due to the electrolysis reaction of the reducing object, the reducing object gas in the cathode chamber 140 moves to the anode chamber 150 via the electrolyte simultaneously with the electrolysis reaction. Furthermore, in the anode chamber 150, the oxidizing object, such as water, produces oxidizing product gas, such as oxygen. Near the inlet of the anode flow path, the anode fluid in the anode chamber 150 is covered by the anode supply fluid supplied from the flow path P2. However, as it approaches the outlet of the anode flow path, the anode flow path forms a gas-liquid double-layer flow of liquid, such as the electrolyte, and gas, such as oxygen. This gas-liquid double-layer flow reduces the electrolysis efficiency. Furthermore, in addition to its function of ion movement, the electrolyte in the anode fluid also has the function of cooling the electrochemical reaction cell EC. In the anode flow path, as the gas generated by the electrolysis reaction increases as it approaches the outlet, the cooling effect decreases.

[0077] The electrochemical reactor of the embodiment includes the gas-liquid separator 18, which separates at least a portion of the oxygen-containing gas from the anode fluid flowing in the anode flow path, thereby suppressing a decrease in electrolysis efficiency and a decrease in cooling effect.

[0078] With respect to the carbon dioxide in cathode chamber 140 and the electrolyte in anode chamber 150, the electrolyte in anode chamber 150 squeezes the gas in cathode chamber 140, thereby adjusting the pressure balance between cathode chamber 140 and anode chamber 150, suppressing mixing of the reaction products in cathode chamber 140 and anode chamber 150, causing the reactants in cathode chamber 140 to be discharged through flow path P3 and the reactants in anode chamber to be discharged through flow path P4. If the gas content in anode chamber 150, which is filled with electrolyte, increases, this pressure balance cannot be maintained, and there is a possibility that the gases in cathode chamber 140 and anode chamber 150 will mix.

[0079] The electrochemical reaction device of the embodiment includes the gas-liquid separator 18 , which can maintain pressure balance between the cathode chamber 140 and the anode chamber 150 by separating at least a portion of the gas containing oxygen from the anode fluid flowing in the anode flow path.

[0080] Thus, the electrochemical reaction device of the embodiment includes the gas-liquid separator 18 , which can improve the device life and electrolysis efficiency by suppressing the reduction of electrolysis efficiency and cooling effect and maintaining the pressure balance between the cathode chamber 140 and the anode chamber 150 .

[0081] The electrolytic reactions such as the oxidation reaction and the reduction reaction based on the electrochemical reaction structure 10 are preferably carried out at a temperature above room temperature (e.g., 25°C) and below 100°C and at a temperature at which the electrolyte is not vaporized. The above temperature is preferably above 60°C and below 95°C, more preferably above 60°C and below 80°C. In order to set the temperature below room temperature, a cooling device such as a cooler is required, and the energy efficiency of the overall system may be reduced. When the temperature exceeds 100°C, the water in the electrolyte becomes vapor, the resistance increases, and the electrolysis efficiency may be reduced.

[0082] The current density of the cathode 11 is not particularly limited, but a high current density is preferred to increase the amount of reduction products produced per unit area. The current density is preferably 100 mA / cm 2 Above and 1.5A / cm 2 Below, more preferably 300mA / cm 2 Above and 700mA / cm 2 Below. Less than 100mA / cm 2 When the reduction product is generated per unit area, the amount is low and a large area is required. 2 , the side reaction of hydrogen production increases and the concentration of the reduction product decreases.

[0083] When Joule heat increases due to an increase in current density, the temperature rises above an appropriate level. Therefore, a cooling mechanism may be provided in or near the electrochemical reaction structure 10. The cooling mechanism may be water cooling or air cooling. Even if the temperature of the electrochemical reaction structure 10 is higher than room temperature, it can be maintained at 100°C or below.

[0084] (Second embodiment)

[0085] When a gas (cathode gas) containing a reduction target such as carbon dioxide is supplied to the cathode chamber 140 , the electrochemical reaction structure 10 includes a second cathode chamber forming a second cathode flow path between the cathode 11 and the separator 13 , and the electrolyte can be supplied to the second cathode chamber. Figure 2 Schematic diagram showing a configuration example of an electrochemical reaction device according to the second embodiment. Figure 2 As shown, the electrochemical reaction device 1 may further include a flow channel plate 19, a cathode chamber 190, a flow channel P5, and a flow channel P6. The following describes portions that differ from the electrochemical reaction device of the first embodiment, and for other portions, the description of the electrochemical reaction device of the first embodiment can be used as appropriate.

[0086] Flow plate 19 forms cathode chamber 190. Cathode chamber 190 is disposed on the surface of flow plate 19, facing cathode 11, and can form a second cathode flow path. Cathode chamber 190 is disposed on the opposite side of cathode 11 from cathode chamber 140. Cathode chamber 190 has an inlet for supplying fluid to cathode chamber 190 and an outlet for discharging fluid from cathode chamber 190. The remaining description of flow plate 19 may refer to the description of flow plate 14 or flow plate 15, as appropriate.

[0087] Flow path P5 is connected to the inlet of cathode chamber 190. The second cathode supply fluid supplied to cathode chamber 190 can flow through flow path P5. The second cathode supply fluid contains an electrolyte. The electrolyte may or may not contain carbon dioxide. Flow path P5 can be connected to a cathode solution supply source. The cathode solution supply source can, for example, supply an electrolyte for the second cathode supply fluid. When the electrolyte contained in the second cathode supply fluid is the same as the electrolyte contained in the anode supply fluid, flow path P5 can be connected to the above-mentioned anode solution supply source.

[0088] Flow path P6 is connected to the outlet of cathode chamber 190. The second cathode discharge fluid discharged from cathode chamber 190 can flow through flow path P6. The second cathode discharge fluid contains carbon compounds and hydrogen generated by the reduction reaction at cathode 11, as well as an electrolyte. After the gaseous and liquid components of the second cathode discharge fluid are separated using a gas-liquid separator, they can be supplied to flow path P5 as an electrolyte for reuse. In this case, a pump may be further provided in the middle of another flow path connecting flow path P5 and flow path P6, so that the separated liquid component is returned to flow path P5 by the pump.

[0089] The flow paths P5 and P6 can be formed using, for example, pipes.

[0090] The electrolyte contained in the second cathode supply fluid is preferably a solution with a high absorption rate of carbon dioxide. The existence form of carbon dioxide in the electrolyte is not necessarily limited to a dissolved state, and bubble-shaped carbon dioxide can be mixed in the electrolyte. As an electrolyte containing carbon dioxide, for example, aqueous solutions containing bicarbonates such as lithium bicarbonate (LiHCO3), sodium bicarbonate (NaHCO3), potassium bicarbonate (KHCO3), cesium bicarbonate (CsHCO3), sodium carbonate (Na2CO3), and potassium carbonate (K2CO3), carbonates, phosphoric acid, boric acid, etc. can be listed. The electrolyte containing carbon dioxide can contain alcohols such as methanol and ethanol, and ketones such as acetone, and can be an alcohol solution or a ketone solution. The electrolyte can be an electrolyte that contains a carbon dioxide absorbent that reduces the reduction potential of carbon dioxide, has high ion conductivity, and absorbs carbon dioxide. The electrolyte contained in the second cathode supply fluid can contain substances that can be applied to the electrolyte contained in the anode supply fluid.

[0091] (Third embodiment)

[0092] Figure 3 Schematic diagram showing an example of the configuration of an electrochemical reaction device according to the third embodiment. Figure 3 As shown, the electrochemical reactor 1 may further include a gas-liquid separator 51, a flow path P7, and a pump 90. The following describes portions different from the electrochemical reactor of the first embodiment, and the description of the electrochemical reactor of the first embodiment can be used as appropriate for other portions.

[0093] The gas-liquid separator 51 is provided midway along the flow path P4.

[0094] The flow path P7 connects, for example, the outlet of the gas-liquid separator 51 to the flow path P2 or the anode fluid supply source. The flow path P7 can be formed using, for example, piping.

[0095] The pump 90 is provided midway along the flow path P7.

[0096] A gas-liquid separator 51 separates the anode exhaust fluid into liquid components such as the electrolyte and gas components such as oxygen, hydrogen, and carbon dioxide. The liquid components are returned to flow path P2 via flow path P7 by pump 90, allowing the anode solution to circulate. The gas components can be recovered via flow path P4 or supplied to downstream equipment.

[0097] (Fourth embodiment)

[0098] Figure 4 It is a schematic diagram showing a configuration example of an electrochemical reaction device according to a fourth embodiment. Figure 4 An example of the structure of the anode flow path is shown. The anode flow path has a serpentine planar shape and includes an inlet (anode flow path inlet) 151 for supplying a fluid to the anode chamber 150, an outlet (anode flow path outlet) 152 for discharging the fluid from the anode chamber 150, an anode flow path section 153, and an anode flow path section 154. The following describes portions that differ from the electrochemical reactor of the first embodiment; for other portions, the description of the electrochemical reactor of the first embodiment can be used as appropriate.

[0099] The anode flow path inlet 151 is connected to the flow path P2 , and the anode flow path outlet 152 is connected to the flow path P4 .

[0100] Anode flow path portion 153 is provided on flow path plate 15, facing anode 12. Anode flow path portion 153 is provided in the anode flow path, upstream of anode flow path portion 154. The inlet of anode flow path portion 153 is connected to anode flow path inlet 151. The outlet of anode flow path portion 153 is connected to flow path P8. Anode flow path portion 153 has a serpentine planar shape.

[0101] Anode flow path portion 154 is provided on flow path plate 15, facing anode 12. Anode flow path portion 154 is provided in the anode flow path, downstream of anode flow path portion 153. The inlet of anode flow path portion 154 is connected to flow path P9. The outlet of anode flow path portion 154 is connected to anode flow path outlet 152. Anode flow path portion 154 can be provided physically separate from anode flow path portion 153. Anode flow path portion 154 has a serpentine planar shape.

[0102] The gas-liquid separator 18 includes, for example, a container having a fluid inlet, a liquid outlet, and a gas outlet and capable of storing the anode fluid, and a gas-liquid separation membrane provided in the container.

[0103] The anode fluid (untreated anode fluid) supplied from the anode flow path portion 153 to the gas-liquid separator 18 flows through the flow path P8. The flow path P8 is connected to the fluid inlet of the gas-liquid separator 18. The flow path P8 may penetrate the flow path plate 15.

[0104] The anode fluid (treated anode fluid) supplied from the gas-liquid separator 18 to the anode flow path portion 154 flows through the flow path P9. The flow path P9 is connected to the liquid outlet of the gas-liquid separator 18 and can penetrate the flow path plate 15.

[0105] The oxygen-containing gas separated by the gas-liquid separator 18 flows through the flow path P10. The flow path P10 is connected to the gas outlet of the gas-liquid separator 18. The separated oxygen-containing gas can be discharged to the outside from the flow path P10 or supplied to other devices.

[0106] The flow paths P8 , P9 , and P10 can be formed using, for example, pipes.

[0107] As described above, the electrochemical reaction device of the fourth embodiment can separate the gas containing oxygen from the anode fluid flowing in the anode flow path even when the gas-liquid separator 18 is provided outside the flow path plate 15 .

[0108] (Fifth embodiment)

[0109] Figure 5 It is a schematic diagram showing a configuration example of an electrochemical reaction device according to a fifth embodiment. Figure 5 An example of the structure of the anode flow path is shown. Figure 5As shown, the electrochemical reaction device includes a gas-liquid separator 18a and a gas-liquid separator 18b. The anode flow path has a serpentine planar shape and includes an inlet (anode flow path inlet) 151 for supplying a fluid to the anode chamber 150, an outlet (anode flow path outlet) 152 for discharging the fluid from the anode chamber 150, an anode flow path portion 153, an anode flow path portion 154, and an anode flow path portion 155. The following describes portions that differ from the electrochemical reaction device of the fourth embodiment; for other portions, the description of the electrochemical reaction device of the fourth embodiment can be used as appropriate.

[0110] The anode flow path inlet 151 is connected to the flow path P2 , and the anode flow path outlet 152 is connected to the flow path P4 .

[0111] Anode flow path portion 153 is provided on flow path plate 15, facing anode 12. Anode flow path portion 153 is provided in the anode flow path, upstream of anode flow path portion 154. The inlet of anode flow path portion 153 is connected to anode flow path inlet 151. The outlet of anode flow path portion 153 is connected to flow path P8a. Anode flow path portion 153 has a serpentine planar shape.

[0112] Anode flow path portion 154 is provided on flow path plate 15, facing anode 12. Anode flow path portion 154 is provided in the anode flow path, downstream of anode flow path portion 153. The inlet of anode flow path portion 154 is connected to flow path P9b. The outlet of anode flow path portion 154 is connected to anode flow path outlet 152. Anode flow path portion 154 can be provided physically separate from anode flow path portion 153. Anode flow path portion 154 has a serpentine planar shape.

[0113] The anode flow path portion 155 is provided on the flow path plate 15, facing the anode 12. The anode flow path portion 155 is provided in the anode flow path at the rear section of the anode flow path portion 153 and at the front section of the anode flow path portion 154. The inlet of the anode flow path portion 155 is connected to the flow path P9a. The outlet of the anode flow path portion 155 is connected to the flow path P8b. The anode flow path portion 155 can be provided physically separate from the anode flow path portion 153 and the anode flow path portion 154. The anode flow path portion 155 has a serpentine planar shape.

[0114] The gas-liquid separator 18a includes, for example, a first container having a first fluid inlet, a first liquid outlet, and a first gas outlet for storing the anode fluid, and a first gas-liquid separation membrane disposed in the first container. The remaining description of the gas-liquid separator 18a can refer to the description of the gas-liquid separator 18 as appropriate.

[0115] The gas-liquid separator 18b includes, for example, a second container having a second fluid inlet, a second liquid outlet, and a second gas outlet for storing the anode fluid, and a second gas-liquid separation membrane disposed in the second container. The remaining description of the gas-liquid separator 18b can refer to the description of the gas-liquid separator 18 as appropriate.

[0116] The anode fluid (untreated anode fluid) supplied from the anode flow path portion 153 to the gas-liquid separator 18a flows through the flow path P8a. The flow path P8a is connected to the first fluid inlet of the gas-liquid separator 18a. The flow path P8a can penetrate the flow path plate 15.

[0117] Anode fluid (anode fluid processed by the gas-liquid separator 18a) supplied from the gas-liquid separator 18a to the anode flow path portion 155 flows through the flow path P9a. The flow path P9a is connected to the first liquid outlet of the gas-liquid separator 18a. The flow path P9a can penetrate the flow path plate 15.

[0118] The oxygen-containing gas separated by the gas-liquid separator 18a flows through flow path P10a. Flow path P10a is connected to the first gas outlet of the gas-liquid separator 18a. The separated oxygen-containing gas can be discharged from flow path P10a to the outside or supplied to other devices.

[0119] Anode fluid (anode fluid processed by gas-liquid separator 18a) supplied from anode flow path portion 155 to gas-liquid separator 18b flows through flow path P8b. Flow path P8b is connected to the second fluid inlet of gas-liquid separator 18b. Flow path P8b may penetrate flow path plate 15.

[0120] Anode fluid (anode fluid processed by gas-liquid separator 18b) supplied from gas-liquid separator 18b to anode flow path portion 154 flows through flow path P9b. Flow path P9b is connected to the second liquid outlet of gas-liquid separator 18b. Flow path P9b may penetrate flow path plate 15.

[0121] The oxygen-containing gas separated by gas-liquid separator 18b flows through flow path P10b. Flow path P10b is connected to the second gas outlet of gas-liquid separator 18b. The separated oxygen-containing gas can be discharged externally from flow path P10b or supplied to other devices.

[0122] The provision of multiple gas-liquid separators 18 can enhance the effect of removing gas from the anode fluid, thereby suppressing a decrease in the cooling effect and enhancing the effect of maintaining the pressure balance between the cathode chamber 140 and the anode chamber 150 .

[0123] (Sixth embodiment)

[0124] Figure 6 It is a schematic diagram showing a configuration example of an electrochemical reaction device according to a sixth embodiment. Figure 6 An example of the structure of the anode flow path is shown. Figure 6As shown, the electrochemical reactor can connect the gas-liquid separator 18 to the flow path P4 instead of the gas-liquid separator 51. The following describes the differences from the electrochemical reactor of the fourth embodiment, and the description of the electrochemical reactor of the fourth embodiment can be used as appropriate for other parts.

[0125] The gas-liquid separator 18 also has a second fluid inlet connected to the flow path P4. By using the gas-liquid separator 18, the anode exhaust fluid can be separated into liquid components such as electrolyte and gas components such as oxygen, hydrogen, and carbon dioxide. The gas component can be recovered or supplied to the subsequent device via the gas-liquid separator 18. The liquid component can be supplied to the flow path P2 via the gas-liquid separator 18. Other descriptions of the gas-liquid separator 18 can refer to the description of the gas-liquid separator 18 in the fourth embodiment as appropriate. By using the gas-liquid separator 18 as a gas-liquid separator for separating gas from the anode fluid flowing in the flow path P4, the electrochemical reaction device can be miniaturized.

[0126] (Seventh embodiment)

[0127] Figure 7 It is a schematic diagram showing a configuration example of an electrochemical reaction device according to a seventh embodiment. Figure 7 An example of the structure of the anode flow path is shown. Figure 7 As shown, the electrochemical reaction device includes flow path P2a and flow path P2b. The following describes the parts that are different from the electrochemical reaction device of the fourth embodiment, and the description of the electrochemical reaction device of the fourth embodiment can be used as appropriate for other parts.

[0128] The anode flow path inlet 151 is connected to the flow path P2a. The description of the flow path P2a can be referred to as appropriate.

[0129] The first inlet of anode flow path section 154 is connected to flow path P9. The second inlet of anode flow path section 154 is located later than the first inlet and is connected to flow path P2b. Flow path P2b can be connected to an anode solution supply source. The description of flow path P2b can be used as appropriate for other descriptions of flow path P2b.

[0130] By providing the flow path P2a and the flow path P2b as the plurality of flow paths P2, the amount of gas in the rear stage of the anode flow path can be relatively reduced.

[0131] (Eighth embodiment)

[0132] Figure 8 It is a schematic diagram showing a configuration example of an electrochemical reaction device according to an eighth embodiment. Figure 8 An example of the structure of the anode flow path is shown. Figure 8As shown, the electrochemical reaction device includes a removed portion 21. The following describes portions that are different from the electrochemical reaction device of the fourth embodiment, and the description of the electrochemical reaction device of the fourth embodiment can be appropriately cited for other portions.

[0133] The removal unit 21 is provided in the gas-liquid separator 18. The removal unit 21 includes at least one of an ion remover and a radical remover.

[0134] The ion remover can remove the metal ions contained in the anode fluid. Metal ions sometimes hinder the reduction reaction of carbon dioxide. Examples of metal ions are titanium ions, divalent iron ions, trivalent iron ions, cobalt ions, nickel ions, chromium ions, niobium ions, iridium ions, etc. Metal ions sometimes react with hydrogen peroxide produced as a side reaction of carbon dioxide reduction to generate hydroxyl radicals. By providing the ion remover, it is possible to suppress the hindrance of the reduction reaction of carbon dioxide and suppress the generation of hydroxyl radicals.

[0135] The free radical remover can remove free radicals contained in the anode fluid. Examples of free radicals include hydroxyl radicals generated from hydrogen peroxide as a side reaction of carbon dioxide reduction. Free radicals can sometimes reduce the durability of the separator 13, such as the electrolyte membrane. By providing the free radical remover, the generation of hydroxyl radicals can be suppressed, thereby improving the durability of the separator 13.

[0136] (Ninth embodiment)

[0137] Figure 9 It is a schematic diagram showing a configuration example of an electrochemical reaction device according to a ninth embodiment. Figure 9 An example of the structure of the anode flow path is shown. Figure 9 As shown, the electrochemical reaction device includes a detection unit 23. The following describes portions that are different from the electrochemical reaction device of the fourth embodiment, and the description of the electrochemical reaction device of the fourth embodiment can be used as appropriate for other portions.

[0138] The detection unit 23 includes at least one of a pH detector and an ionic impurity detector. The at least one detector is connected to the gas-liquid separator 18 via a flow path and is capable of detecting the pH and ionic impurity concentration of the anode fluid from the gas-liquid separator 18. Examples of ionic impurities include potassium ions, sodium ions, cesium ions, titanium ions, divalent iron ions, trivalent iron ions, cobalt ions, nickel ions, chromium ions, niobium ions, and iridium ions. The provision of the detection unit 23 allows for confirmation of changes in the electrolyte composition in the anode fluid.

[0139] (10th embodiment)

[0140] Figure 10 It is a schematic diagram showing a configuration example of an electrochemical reaction device according to a tenth embodiment. Figure 10 An example of the structure of the anode flow path is shown. Figure 10 As shown, the electrochemical reaction device includes a detection unit 23 and a pH adjustment unit 25. The following describes portions that differ from the electrochemical reaction device of the fourth embodiment, and the description of the electrochemical reaction device of the fourth embodiment can be used as appropriate for other portions.

[0141] The detection unit 23 includes a pH detector. The pH detector is connected to the gas-liquid separator 18 via a flow path and can detect the pH of the anode fluid from the gas-liquid separator 18. By providing the detection unit 23, for example, changes in the composition of the electrolyte in the anode fluid can be confirmed.

[0142] The pH adjustment unit 25 includes, for example, a liquid supply source. The liquid supply source can supply water or an electrolyte adjusted to a desired concentration to the gas-liquid separator 18 via a flow path. This allows the pH of the anode fluid to be adjusted. The pH of the anode fluid is preferably between 6.0 and 9.0. More preferably, it is between 7.0 and 8.7. The pH adjustment unit 25 can be controlled based on the pH detection results of the anode fluid detected by the detection unit 23, and the pH of the anode fluid can be adjusted based on the detection results.

[0143] (11th embodiment)

[0144] Figure 11 It is a schematic diagram showing a configuration example of an electrochemical reaction device according to an eleventh embodiment. Figure 11 An example of the structure of the anode flow path is shown. Figure 11 As shown, the electrochemical reaction device 1 includes a recovery unit 26. The following describes portions that are different from the electrochemical reaction device of the fourth embodiment, and the description of the electrochemical reaction device of the fourth embodiment can be used as appropriate for other portions.

[0145] The recovery unit 26 is disposed within the gas-liquid separator 18. The recovery unit 26 can recover catalysts such as the anode catalyst from the anode fluid to the outside. The anode catalyst may flow from the anode 12 into the anode fluid. The recovery unit 26 includes a filter within the container of the gas-liquid separator 18. The provision of the recovery unit 26 allows the catalyst to be reused.

[0146] (12th embodiment)

[0147] Figure 12 Schematic diagram showing a configuration example of an electrochemical reaction device according to the twelfth embodiment. Figure 12 As shown, the electrochemical reaction device 1 includes a group formed by stacking a plurality of electrochemical reaction cells EC. Hereinafter, the parts different from the electrochemical reaction device of the first embodiment will be described, and the description of the electrochemical reaction device of the first embodiment can be used as appropriate for other parts.

[0148] The electrochemical reaction device 1 further includes a flow passage plate 170 between the plurality of electrochemical reaction cells EC. The flow passage plate 170 includes a cathode chamber 140 provided on the cathode 11 side and an anode chamber 150 provided on the anode 12 side. One end of the cell group is electrically connected to the current collector 16 via the flow passage plate 14. The other end of the cell group is electrically connected to the current collector 17 via the flow passage plate 15. The current collector 16 and the current collector 17 are electrically connected to the current collector 17. Figure 1 The electrochemical reaction device shown is similarly connected to the power source 20. The remaining description of the flow channel plate 170 can refer to the description of the flow channel plate 14 or the flow channel plate 15 as appropriate.

[0149] The multiple anode flow paths of the multiple electrochemical reaction cells EC are connected in parallel. The inlets of the multiple anode flow paths can be connected to flow path P2 using, for example, a manifold-type piping different from that used for flow path P2. The outlets of the multiple anode flow paths can be connected to flow path P4 using, for example, a manifold-type piping different from that used for flow path P4. This is not limiting; the multiple anode flow paths can be connected to different flow paths P2 and P4.

[0150] The cathode flow paths of the multiple electrochemical reaction cells EC are connected in parallel. The inlets of the multiple cathode flow paths can be connected to flow path P1 using, for example, manifold-type piping. The outlets of the multiple cathode flow paths can be connected to flow path P3 using, for example, manifold-type piping. This is not limiting; the multiple cathode flow paths can be connected to different flow paths P1 and P3.

[0151] Figure 12 In this embodiment, a single gas-liquid separator 18 is disposed midway along the anode flow path of multiple electrochemical reaction cells EC, enabling centralized gas-liquid separation for the multiple anode flow paths. However, a smaller number of gas-liquid separators 18 than the number of electrochemical reaction cells EC may be disposed midway along the anode flow paths of the multiple electrochemical reaction cells EC. Furthermore, by disposing the gas-liquid separator 18 within the housing of the cell group, the electrochemical reaction device 1 can be miniaturized. Furthermore, by disposing the gas-liquid separator 18, oxygen-containing gas can be separated from the linear anode flow path, thereby suppressing a decrease in electrolysis efficiency. Furthermore, a decrease in cooling efficiency can be suppressed.

[0152] (Thirteenth embodiment)

[0153] Figure 13 Schematic diagram showing an example of the configuration of an electrochemical reaction device according to the 13th embodiment. Figure 13 As shown, the electrochemical reaction device 1 includes a stack of multiple electrochemical reaction cells EC, and a gas-liquid separator 18 connected to the anode flow path. The following describes the parts that differ from the electrochemical reaction device of the 12th embodiment. For other parts, the description of the electrochemical reaction device of the 12th embodiment can be used as appropriate.

[0154] The gas-liquid separator 18 can be formed, for example, by disposing a gas-liquid separation membrane above the anode chamber 150. This can form a layered structure comprising a liquid layer containing water and an electrolyte and a gas layer containing a gas containing oxygen. The gas separated by the gas-liquid separation membrane is discharged to the outside via a flow path P10 connected to the gas outlet of the gas-liquid separator 18. Therefore, the electrochemical reaction device does not need to have flow paths P8 and P9.

[0155] The gas outlets of the multiple gas-liquid separators 18 of the multiple electrochemical reaction cells EC are connected in parallel. The gas outlets of the multiple gas-liquid separators 18 can be connected to the flow path P10 using, for example, manifold-type piping. The flow path P10 can pass through the flow path plate 15. The gas outlets of the gas-liquid separators 18 of different electrochemical reaction cells EC do not need to be connected to each other.

[0156] This method can be used with both individual electrochemical reaction cells and cell groups. However, in the case of a cell group, since a fluid inlet to the gas-liquid separator 18 is not required midway along the anode flow path, the electrochemical reaction device 1 can be miniaturized. Furthermore, the provision of the gas-liquid separator 18 allows oxygen-containing gas to be separated from the linear anode flow path, thereby suppressing a decrease in electrolysis efficiency. Furthermore, a decrease in cooling efficiency can be suppressed.

[0157] (14th embodiment)

[0158] Figure 14 and Figure 15 It is a schematic diagram showing a configuration example of an electrochemical reaction device according to a fourteenth embodiment. Figure 14 An example of a planar structure of an anode flow path is shown. Figure 15 An example of the cross-sectional structure of the anode flow path is shown. Figure 14 and Figure 15 As shown, the electrochemical reactor 1 includes a plurality of anode flow paths including a plurality of anode chambers 150. The following describes portions different from the electrochemical reactor of the fourth embodiment, and the description of the electrochemical reactor of the fourth embodiment can be appropriately cited for other portions.

[0159] The plurality of anode flow paths have a strip-like planar shape and each has an inlet (anode flow path inlet) 151 for supplying a fluid to the anode chamber 150 and an outlet (anode flow path outlet) 152 for discharging the fluid from the anode chamber 150 .

[0160] The gas-liquid separator 18 is formed by disposing a gas-liquid separation membrane above the anode chamber 150. Figure 15 As shown, there may be multiple gas-liquid separators 18 connected to different anode chambers 150. Figure 14In the case of the linear anode flow path shown, gas-liquid separator 18 is preferably formed by disposing a gas-liquid separation membrane on the anode flow path. The oxygen-containing gas separated by gas-liquid separator 18 can be discharged through flow path P10 connected to the gas outlet of gas-liquid separator 18. Therefore, the electrochemical reactor does not need to include flow paths P8 and P9. Flow path P10 can pass through flow path plate 15.

[0161] By providing multiple linear anode flow paths, for example, the flow paths can be shortened, thereby suppressing gas accumulation in the anode fluid. Furthermore, by providing the gas-liquid separator 18, oxygen-containing gas can be separated from the linear anode flow paths, thereby suppressing a decrease in electrolysis efficiency. Furthermore, a decrease in cooling effectiveness can be suppressed.

[0162] like Figure 14 and Figure 15 As shown, on the surface of the flow plate 15 forming the anode chamber 150, the number of turns in each of the multiple anode flow paths is preferably two or fewer. By setting this number to two or fewer, for example, the flow path can be shortened, thereby suppressing gas accumulation in the anode fluid. On the surface of the flow plate 15 forming the anode chamber 150, each of the multiple anode flow paths may, for example, turn once at the point from flow path P2 to inlet 151 and once at the point from outlet 152 to flow path P4.

[0163] Example

[0164] Electrochemical reaction devices of Examples 1 to 12 and Comparative Examples 1 and 2 were prepared. Furthermore, in order to evaluate the characteristics of durability and electrolysis efficiency, a cathode supply fluid containing carbon dioxide was supplied to the cathode flow path, and an anode supply fluid containing an electrolyte was supplied to the anode flow path. The flow rate was 700 mA / cm 2 Each electrochemical reaction device was operated under the following conditions. The voltage was controlled by the power supply 20 so that a current density of 700 mA / cm was applied between the cathode 11 and the anode 12. 2 Electric current is passed, carbon dioxide is reduced to produce carbon monoxide at cathode 11, and water is oxidized to produce oxygen at anode 12. Furthermore, cathode exhaust fluid discharged from the cathode flow path is collected and analyzed to calculate the carbon monoxide production Faraday efficiency.

[0165] Each electrochemical reactor was evaluated based on changes in the Faraday efficiency for carbon monoxide generation as follows. An electrochemical reactor in which the time from the start of operation until the Faraday efficiency for carbon monoxide generation reached 90% or less was less than 100 hours was rated as × (Bad), while an electrochemical reactor in which the time from the start of operation until the Faraday efficiency for carbon monoxide generation reached 90% or less was rated as 0 (Good). Furthermore, an electrochemical reactor in which the time from the start of operation until the Faraday efficiency for carbon monoxide generation reached 95% or less was more than 100 hours was rated as ◎ (Very Good).

[0166] (Comparative Example 1)

[0167] Figure 16 and Figure 17 Schematic diagram showing a configuration example of an electrochemical reaction device of Comparative Example 1. The electrochemical reaction device of Comparative Example 1 has Figure 16 The structure shown has Figure 17 The structure of the anode chamber 150, the flow path plate 15, and the anode flow path shown does not have any gas-liquid separator 18. The electrochemical reaction device of Comparative Example 1 is Figure 1 The electrochemical reaction device shown in FIG. 1 is different from the electrochemical reaction device shown in FIG. 1 in that the gas-liquid separator 18 is not provided. The evaluation result of the electrochemical reaction device of Comparative Example 1 was rated as ×.

[0168] (Example 1)

[0169] The electrochemical reaction device of Example 1 is different from the electrochemical reaction device of Comparative Example 1 in that Figure 1 The structure shown has Figure 4 The structure of the anode chamber 150, the flow path plate 15, the anode flow path, and the gas-liquid separator 18 is shown. The evaluation result of the electrochemical reaction device of Example 1 was 0. This shows that the reduction in the concentration of the gas contained in the anode fluid can suppress the reduction in the Faraday efficiency of carbon monoxide production.

[0170] (Example 2)

[0171] The electrochemical reaction device of Example 2 is different from the electrochemical reaction device of Comparative Example 1 in that Figure 1 The structure shown has Figure 5 The structure of the anode chamber 150, flow plate 15, anode flow path, and gas-liquid separator 18 is shown. The evaluation result of the electrochemical reactor of Example 2 was ◎. This shows that the reduction in the concentration of the gas contained in the anode fluid can suppress the reduction in the Faraday efficiency of carbon monoxide production.

[0172] (Example 3)

[0173] The electrochemical reaction device of Example 3 is different from the electrochemical reaction device of Comparative Example 1 in that Figure 1The structure shown has Figure 6 The structure of the anode chamber 150, the flow plate 15, the anode flow path, and the gas-liquid separator 18 is shown. The evaluation result of the electrochemical reaction device of Example 3 was 0. This shows that the reduction in the concentration of the gas contained in the anode fluid can suppress the reduction in the Faraday efficiency of carbon monoxide production.

[0174] (Example 4)

[0175] The electrochemical reaction device of Example 4 is different from the electrochemical reaction device of Comparative Example 1 in that Figure 1 The structure shown has Figure 7 The structure of the anode chamber 150, flow plate 15, anode flow path, and gas-liquid separator 18 is shown. The evaluation result of the carbon dioxide reduction unit of Example 4 was ◎. This shows that the reduction in the Faraday efficiency of carbon monoxide production can be suppressed by reducing the concentration of the gas contained in the anode fluid.

[0176] (Example 5)

[0177] The electrochemical reaction device of Example 5 is different from the electrochemical reaction device of Comparative Example 1 in that Figure 1 The structure shown has Figure 8 The structure of the anode chamber 150, flow plate 15, anode flow path, and gas-liquid separator 18 shown in FIG. 1 includes a removal unit 21 including a metal ion remover. The evaluation result of the electrochemical reactor of Example 5 was 0. Furthermore, the concentration of metal ions in the electrolyte was halved compared to the electrochemical reactor of Comparative Example 1. This indicates that reducing the metal ions in the electrolyte can suppress the decrease in the Faraday efficiency of carbon monoxide production.

[0178] (Example 6)

[0179] The electrochemical reaction device of Example 6 is different from the electrochemical reaction device of Comparative Example 1 in that Figure 1 The structure shown has Figure 8 The structure shown in the figure, which includes the anode chamber 150, flow plate 15, anode flow path, and gas-liquid separator 18, includes a removal section 21 containing a free radical scavenger. The evaluation result of the electrochemical reactor of Example 6 was ◎. Because the electrochemical reactor of Example 6 includes the free radical scavenger, no degradation of the electrolyte membrane or gasket was observed compared to the electrochemical reactor of Comparative Example 1. This demonstrates that the reduction in the Faraday efficiency of carbon monoxide production can be suppressed by removing free radicals.

[0180] (Example 7)

[0181] The electrochemical reaction device of Example 7 is different from the electrochemical reaction device of Comparative Example 1 in that Figure 1The structure shown has Figure 9 The structure shown in the figure, comprising the anode chamber 150, flow plate 15, anode flow path, and gas-liquid separator 18, includes a detection unit 23 comprising a pH detector. The evaluation result of the electrochemical reactor of Example 7 was 0. Because the electrochemical reactor of Example 7 includes a pH detector, it is possible to adjust the pH of the electrolyte to an appropriate value even if the pH of the electrolyte changes. This indicates that by adjusting the pH of the electrolyte, a decrease in the Faraday efficiency of carbon monoxide generation can be suppressed.

[0182] (Example 8)

[0183] The electrochemical reaction device of Example 8 is different from the electrochemical reaction device of Comparative Example 1 in that Figure 1 The structure shown has Figure 9 The structure shown, comprising the anode chamber 150, the flow plate 15, the anode flow path, and the gas-liquid separator 18, includes a detection unit 23 including an ion impurity detector. The evaluation result of the electrochemical reaction device of Example 8 was 0. Since the electrochemical reaction device of Example 8 includes the ion impurity detector, it is possible to confirm an increase in the amount of ion impurities in the electrolyte.

[0184] (Example 9)

[0185] The electrochemical reaction device of Example 9 is different from the electrochemical reaction device of Comparative Example 1 in that Figure 1 The structure shown has Figure 10 The illustrated structure of the anode chamber 150, flow plate 15, anode flow path, and gas-liquid separator 18 includes a detection unit 23 including a pH detector and a pH adjustment unit 25. The pH of the electrolyte was adjusted to 8.5 using the pH adjustment unit 25. The evaluation result of the electrochemical reactor of Example 9 was rated ◎. This demonstrates that the reduction in the Faraday efficiency of carbon monoxide production can be suppressed by adjusting the pH of the electrolyte.

[0186] (Comparative Example 2)

[0187] Figure 18 Schematic diagram showing the configuration of the electrochemical reaction device of Comparative Example 2. The electrochemical reaction device of Comparative Example 2 differs from the electrochemical reaction device of Comparative Example 1 in that Figure 18 The structure shown has Figure 18 The structures of the anode chamber 150, the flow channel plate 15, and the anode flow channel are shown. The evaluation result of the electrochemical reaction device of Comparative Example 2 was x.

[0188] (Example 10)

[0189] The electrochemical reaction device of Example 10 is different from the electrochemical reaction device of Comparative Example 1 in that Figure 12The structure shown has Figure 4 The structure of the anode chamber 150, the flow path plate 15, the anode flow path, and the gas-liquid separator 18 is shown. The evaluation result of the electrochemical reaction device of Example 10 was 0.

[0190] (Example 11)

[0191] The electrochemical reaction device of Example 11 is different from the electrochemical reaction device of Comparative Example 1 in that Figure 13 The structure shown has Figure 4 The structure of the anode chamber 150, the flow path plate 15, and the anode flow path is shown. The evaluation result of the electrochemical reaction device of Example 11 was 0.

[0192] (Example 12)

[0193] The electrochemical reaction device of Example 12 is different from the electrochemical reaction device of Comparative Example 1 in that Figure 13 The structure shown has Figure 14 and Figure 15 The structures of the anode chamber 150 and the flow channel plate 15 are shown. The evaluation result of the electrochemical reaction device of Example 12 was ⊚.

[0194] It should be noted that the configurations of the above-mentioned embodiments can be applied in combination, and a portion can also be replaced. Here, several embodiments of the present invention are described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the subject matter of the invention. These embodiments and their variations are included in the scope and subject matter of the invention, and are also included in the invention described in the patent claims and their equivalents.

[0195] The above-mentioned embodiments can be summarized into the following technical solutions.

[0196] (Technical Solution 1)

[0197] An electrochemical reaction device comprising:

[0198] An electrochemical reaction structure comprising: a cathode having a reduction catalyst that promotes a reduction reaction in which carbon dioxide is reduced to form a carbon compound; an anode having an oxidation catalyst that promotes an oxidation reaction in which water is oxidized to form oxygen; a separator disposed between the cathode and the anode; a cathode flow path facing the cathode; and an anode flow path facing the anode.

[0199] a first flow path connected to the inlet of the cathode flow path and through which a first fluid containing the carbon dioxide flows and is supplied to the cathode flow path;

[0200] a second flow path connected to the inlet of the anode flow path and through which a second fluid including the water flows and is supplied to the anode flow path;

[0201] a third flow path connected to the outlet of the cathode flow path and through which flows a third fluid discharged from the cathode flow path and containing the carbon compound;

[0202] a fourth flow path connected to the outlet of the anode flow path and through which a fourth fluid discharged from the anode flow path and containing the water and the oxygen flows; and

[0203] A gas-liquid separator is provided in the middle of the anode flow path or in contact with the anode flow path, and processes a fifth fluid containing the water and the oxygen flowing in the anode flow path to separate the gas containing the oxygen from the fifth fluid.

[0204] (Technical Solution 2)

[0205] The electrochemical reaction device according to technical solution 1 further comprises:

[0206] a second cathode flow path provided between the cathode and the separator;

[0207] a fifth flow path connected to the inlet of the second cathode flow path and through which a sixth fluid containing an electrolyte flows and is supplied to the second cathode flow path; and

[0208] A sixth flow path is connected to the outlet of the second cathode flow path and is provided so that the seventh fluid discharged from the second cathode flow path flows.

[0209] (Technical Solution 3)

[0210] The electrochemical reaction device according to claim 1 further comprises: a first current collector connected to the cathode, and a second current collector connected to the anode.

[0211] The first current collector and the second current collector are connected to a power source.

[0212] (Technical Solution 4)

[0213] The electrochemical reaction device according to claim 1 includes a plurality of the gas-liquid separators.

[0214] (Technical Solution 5)

[0215] In the electrochemical reaction device according to claim 1 , the gas-liquid separator is connected to the fourth flow path, and separates the gas containing oxygen from the fourth fluid by processing the fourth fluid from the fourth flow path.

[0216] (Technical Solution 6)

[0217] The electrochemical reaction device according to claim 1 further comprises: a second gas-liquid separator for separating the gas containing oxygen from the fourth fluid by treating the fourth fluid; and

[0218] a seventh flow path in which the treated fourth fluid supplied from the second gas-liquid separator to the second flow path flows.

[0219] (Technical Solution 7)

[0220] The electrochemical reaction device according to technical solution 1 comprises a plurality of the gas-liquid separators.

[0221] The electrochemical reaction structure has a plurality of anode flow paths.

[0222] The plurality of anode flow paths are connected in parallel with each other,

[0223] One of the plurality of gas-liquid separators is disposed in contact with one of the plurality of anode flow paths.

[0224] Another one of the plurality of gas-liquid separators is provided in contact with another one of the plurality of anode flow paths.

[0225] (Technical Solution 8)

[0226] The electrochemical reaction device according to any one of Technical Solutions 1 to Technical Solutions 7 further comprises a removal unit, which is arranged in the gas-liquid separator and has at least one remover selected from an ion remover for removing metal ions from the fifth fluid and a radical remover for removing hydroxyl radicals from the fifth fluid.

[0227] (Technical Solution 9)

[0228] The electrochemical reaction device according to any one of Technical Solutions 1 to Technical Solutions 7 further comprises at least one detector connected to the gas-liquid separator and selected from a pH detector for detecting the pH of the fifth fluid and an ion impurity detector for detecting the concentration of ionic impurities in the fifth fluid.

[0229] (Technical Solution 10)

[0230] The electrochemical reaction device according to claim 9 further comprises a pH adjustment unit connected to the gas-liquid separator for adjusting the pH of the fifth fluid.

[0231] (Technical Solution 11)

[0232] The electrochemical reaction device according to any one of claims 1 to 7 further comprises a recovery unit provided in the gas-liquid separator and configured to recover the oxidation catalyst from the fifth fluid.

[0233] (Technical Solution 12)

[0234] The electrochemical reaction device according to claim 1 comprises a group including a plurality of the electrochemical reaction structures stacked on each other.

[0235] The gas-liquid separator is provided midway through each of the plurality of anode flow paths passing through the plurality of electrochemical reaction structures.

[0236] (Technical Solution 13)

[0237] The electrochemical reaction device according to claim 1 comprises: a group including a plurality of the electrochemical reaction structures stacked on each other, and a plurality of the gas-liquid separators;

[0238] The plurality of anode flow paths of the plurality of electrochemical reaction structures are connected in parallel with each other.

[0239] One of the plurality of gas-liquid separators is disposed in contact with one of the plurality of anode flow paths.

[0240] Another one of the plurality of gas-liquid separators is provided in contact with another one of the plurality of anode flow paths.

[0241] (Technical Solution 14)

[0242] The electrochemical reaction device according to claim 1, wherein the anode flow path comprises:

[0243] a first anode flow path portion connected to the inlet of the anode flow path and facing the anode;

[0244] a second anode flow path portion connected to the outlet of the anode flow path and facing the anode;

[0245] an eighth flow path in which the fifth fluid supplied from the first anode flow path portion to the gas-liquid separator flows; and

[0246] a ninth flow path in which the treated fifth fluid supplied from the gas-liquid separator to the second anode flow path portion flows.

[0247] (Technical Solution 15)

[0248] A method for operating an electrochemical reaction device, wherein the electrochemical reaction device comprises:

[0249] An electrochemical reaction structure comprising: a cathode having a reduction catalyst that promotes a reduction reaction in which carbon dioxide is reduced to form a carbon compound; an anode having an oxidation catalyst that promotes an oxidation reaction in which water is oxidized to form oxygen; a separator disposed between the cathode and the anode; a cathode flow path facing the cathode; and an anode flow path facing the anode.

[0250] a first flow path connected to the inlet of the cathode flow path and through which a first fluid containing the carbon dioxide flows and is supplied to the cathode flow path;

[0251] a second flow path connected to the inlet of the anode flow path and through which a second fluid including the water flows and is supplied to the anode flow path;

[0252] a third flow path connected to the outlet of the cathode flow path and through which flows a third fluid discharged from the cathode flow path and containing the carbon compound; and

[0253] a fourth flow path connected to the outlet of the anode flow path and through which a fourth fluid discharged from the anode flow path and containing the water and the oxygen flows;

[0254] The operating method supplies the first fluid to the cathode flow path, supplies the second fluid to the anode flow path, and supplies current or voltage to the electrochemical reaction structure, thereby reducing the carbon dioxide at the cathode to generate the carbon compound, oxidizing the water at the anode to generate the oxygen, and separating the gas containing the oxygen from the fifth fluid by treating the fifth fluid flowing in the anode flow path and containing the water and the oxygen.

Claims

1. An electrochemical reaction device comprising: An electrochemical reaction structure comprising: A cathode having a reduction catalyst that promotes a reduction reaction in which carbon dioxide is reduced to form a carbon compound, an anode having an oxidation catalyst that promotes an oxidation reaction in which water is oxidized to form oxygen, a separator provided between the cathode and the anode, a cathode flow path facing the cathode, and an anode flow path facing the anode; a first flow path connected to the inlet of the cathode flow path and through which a first fluid containing the carbon dioxide flows and is supplied to the cathode flow path; a second flow path connected to the inlet of the anode flow path and through which a second fluid including the water flows and is supplied to the anode flow path; a third flow path connected to the outlet of the cathode flow path and through which flows a third fluid discharged from the cathode flow path and containing the carbon compound; a fourth flow path connected to the outlet of the anode flow path and through which a fourth fluid discharged from the anode flow path and containing the water and the oxygen flows; and A gas-liquid separator is provided in the middle of the anode flow path or in contact with the anode flow path, and processes a fifth fluid containing the water and the oxygen flowing in the anode flow path to separate the gas containing the oxygen from the fifth fluid.

2. The electrochemical reaction device according to claim 1, further comprising: a second cathode flow path provided between the cathode and the separator; a fifth flow path connected to the inlet of the second cathode flow path and through which a sixth fluid containing an electrolyte flows and is supplied to the second cathode flow path; and A sixth flow path is connected to the outlet of the second cathode flow path and is provided so that the seventh fluid discharged from the second cathode flow path flows.

3. The electrochemical reaction device according to claim 1, further comprising: a first current collector connected to the cathode, and a second current collector connected to the anode. in, The first current collector and the second current collector are connected to a power source. The electrochemical reaction device according to claim 1 , comprising a plurality of the gas-liquid separators.

5. The electrochemical reaction device according to claim 1, wherein The gas-liquid separator is connected to the fourth flow path, and processes the fourth fluid from the fourth flow path to separate the gas containing oxygen from the fourth fluid.

6. The electrochemical reaction device according to claim 1, further comprising: a second gas-liquid separator for separating the gas containing oxygen from the fourth fluid by treating the fourth fluid; and a seventh flow path in which the treated fourth fluid supplied from the second gas-liquid separator to the second flow path flows.

7. The electrochemical reaction device according to claim 1, comprising a plurality of the gas-liquid separators. The electrochemical reaction structure has a plurality of anode flow paths. The plurality of anode flow paths are connected in parallel with each other, One of the plurality of gas-liquid separators is disposed in contact with one of the plurality of anode flow paths. Another one of the plurality of gas-liquid separators is provided in contact with another one of the plurality of anode flow paths.

8. The electrochemical reaction device according to any one of claims 1 to 7 further comprises a removal unit, wherein the removal unit is arranged in the gas-liquid separator and has at least one remover selected from an ion remover for removing metal ions from the fifth fluid and a radical remover for removing hydroxyl radicals from the fifth fluid.

9. The electrochemical reaction device according to any one of claims 1 to 7 further comprises at least one detector connected to the gas-liquid separator and selected from a pH detector for detecting the pH of the fifth fluid and an ion impurity detector for detecting the concentration of ionic impurities in the fifth fluid. 10 . The electrochemical reaction device according to claim 9 , further comprising a pH adjustment unit connected to the gas-liquid separator and configured to adjust the pH of the fifth fluid. 11 . The electrochemical reaction device according to claim 1 , further comprising a recovery unit provided in the gas-liquid separator and configured to recover the oxidation catalyst from the fifth fluid.

12. The electrochemical reaction device according to claim 1, comprising a group including a plurality of the electrochemical reaction structures stacked on each other. The gas-liquid separator is provided midway through each of the plurality of anode flow paths passing through the plurality of electrochemical reaction structures.

13. The electrochemical reaction device according to claim 1, comprising: a group including a plurality of the electrochemical reaction structures stacked on each other, and a plurality of the gas-liquid separators; The plurality of anode flow paths of the plurality of electrochemical reaction structures are connected in parallel with each other. One of the plurality of gas-liquid separators is disposed in contact with one of the plurality of anode flow paths. Another one of the plurality of gas-liquid separators is provided in contact with another one of the plurality of anode flow paths.

14. The electrochemical reaction device according to claim 1, wherein The anode flow path comprises: a first anode flow path portion connected to the inlet of the anode flow path and facing the anode; a second anode flow path portion connected to the outlet of the anode flow path and facing the anode; an eighth flow path in which the fifth fluid supplied from the first anode flow path portion to the gas-liquid separator flows; and a ninth flow path in which the treated fifth fluid supplied from the gas-liquid separator to the second anode flow path portion flows.

15. A method for operating an electrochemical reaction device, which is a method for operating an electrochemical reaction device, wherein: The electrochemical reaction device comprises: An electrochemical reaction structure comprising: a cathode having a reduction catalyst that promotes a reduction reaction in which carbon dioxide is reduced to form a carbon compound; an anode having an oxidation catalyst that promotes an oxidation reaction in which water is oxidized to form oxygen; a separator disposed between the cathode and the anode; a cathode flow path facing the cathode; and an anode flow path facing the anode. a first flow path connected to the inlet of the cathode flow path and through which a first fluid containing the carbon dioxide flows and is supplied to the cathode flow path; a second flow path connected to the inlet of the anode flow path and through which a second fluid including the water flows and is supplied to the anode flow path; a third flow path connected to the outlet of the cathode flow path and through which flows a third fluid discharged from the cathode flow path and containing the carbon compound; and a fourth flow path connected to the outlet of the anode flow path and through which a fourth fluid discharged from the anode flow path and containing the water and the oxygen flows; The operating method supplies the first fluid to the cathode flow path, supplies the second fluid to the anode flow path, and supplies current or voltage to the electrochemical reaction structure, thereby reducing the carbon dioxide at the cathode to generate the carbon compound, oxidizing the water at the anode to generate the oxygen, and separating the gas containing the oxygen from the fifth fluid by treating the fifth fluid flowing in the anode flow path and containing the water and the oxygen.

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