Electrolytic apparatus and electrolytic method

Abstract

To provide an electrolysis apparatus capable of determining the state of an electrolysis cell.SOLUTION: An electrolysis apparatus 1 in an embodiment comprises an electrolysis cell 2 comprising a cathode portion where a reduction electrode is disposed, an anode portion where an oxidation electrode is disposed, and a diaphragm provided between the cathode portion and the anode portion, a supply power characteristic acquisition portion 4 for acquiring the characteristics of the power supplied to the electrolysis cell 2, an input gas characteristic acquisition portion 6 for acquiring the characteristics of the gas input to the electrolysis cell 2, an electrical characteristic acquisition portion 7 for acquiring the electrical characteristic of the electrolysis cell 2, an output gas characteristic acquisition portion 8 for acquiring the characteristic of the output gas of the electrolysis cell 2, a temperature acquisition portion 10 for acquiring the temperature of the electrolysis cell 2, a data storage portion 11 for storing data from each acquisition portion, and a data processing portion 12 for determining the state of the electrolysis cell 2 by processing the data sent from the data storage portion 11.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] Embodiments of the present invention relate to an electrolytic apparatus and an electrolytic method. [Background technology]

[0002] In recent years, concerns about the depletion of fossil fuels such as oil and coal have led to increased expectations for renewable energy sources that can be used sustainably. Examples of renewable energy sources include solar power, hydroelectric power, wind power, and geothermal power. However, because the amount of power generated depends on weather and natural conditions, these are variable power sources, making it difficult to ensure a stable power supply. Therefore, attempts are being made to adjust power by combining variable power sources with storage batteries. However, storing electricity presents challenges such as the cost of storage batteries and losses during storage.

[0003] Furthermore, as an attempt at decarbonization, water electrolysis technology, which generates hydrogen (H2) by electrolyzing water (H2O), and carbon dioxide electrolysis technology, which electrochemically reduces carbon dioxide (CO2) to chemical substances (chemical energy) such as carbon monoxide (CO), formic acid (HCOOH), methanol (CH3OH), methane (CH4), acetic acid (CH3COOH), ethanol (C2H5OH), ethane (C2H6), and ethylene (C2H4), are attracting attention. Connecting a fluctuating power source using renewable energy to these electrolysis devices offers the advantage of simultaneously regulating power, producing hydrogen, and utilizing carbon dioxide as a resource.

[0004] One example of a carbon dioxide electrolytic device is a structure in which a cathode solution and CO2 gas are brought into contact with the cathode, and an anode solution is brought into contact with the anode. This configuration is referred to here as a carbon dioxide electrolytic cell. When such an electrolytic cell is used to carry out a reaction for a long period of time in which a constant current is passed through the cathode and anode to produce CO from CO2, there is a problem in that the cell output deteriorates over time, such as a decrease in the amount of CO produced or an increase in the cell voltage. One of the points of deterioration is the phenomenon in which salts caused by the electrolyte of the solution precipitate in the gas flow path, which obstructs the flow of gas, etc., and the introduction of a refresh operation to dissolve the salts is being considered.

[0005] However, in electrolytic devices using carbon dioxide (CO2) and other materials, it is becoming clear that there are multiple types of degradation phenomena, in addition to phenomena such as salt deposition in the flow path. Furthermore, in nitrogen (N2) electrolytic devices, for example, in addition to degradation phenomena similar to those in CO2 electrolysis, there are also degradation phenomena specific to N2 electrolysis. For these reasons, it is necessary to appropriately adjust the judgment criteria depending on the type of electrolytic material and degradation, such as continuing operation or stopping operation and performing maintenance on the electrolytic cell, depending on the electrolytic material and the location of degradation. For this reason, it is necessary to determine the cell condition, including the state and type of degradation of the electrolytic cell. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2021-147680 [Patent Document 2] Japanese Patent Publication No. 2021-046574 [Patent Document 3] Japanese Patent Publication No. 2020-045515 [Patent Document 4] Japanese Patent Publication No. 2019-167557 [Overview of the project] [Problems that the invention aims to solve]

[0007] The problem that this invention aims to solve is to provide an electrolytic apparatus and electrolytic method that enable the determination of the state of an electrolytic cell. [Means for solving the problem]

[0008] The electrolytic apparatus of the embodiment includes an electrolytic cell comprising: a cathode section to which a gas or liquid containing the substance to be reduced is supplied and a reduction electrode is placed; an anode section to which a liquid containing the substance to be oxidized is supplied and an oxidation electrode is placed; and a diaphragm provided between the cathode section and the anode section; a power supply characteristic acquisition unit to acquire the characteristics of the power supplied to the electrolytic cell; an input gas characteristic acquisition unit to acquire the characteristics of the gas input to the electrolytic cell; an electrical characteristic acquisition unit to acquire the electrical characteristics of the electrolytic cell; an output gas characteristic acquisition unit to acquire the characteristics of the output gas of the electrolytic cell; and a temperature control unit to control the temperature of the electrolytic cell. Department and The system comprises a temperature acquisition unit for acquiring the temperature of the electrolytic cell, a data storage unit for accumulating data from the power supply characteristics acquisition unit, the input gas characteristics acquisition unit, the electrical characteristics acquisition unit, the output gas characteristics acquisition unit, and the temperature acquisition unit, and a data processing unit that receives the data from the data storage unit, processes the data, and determines the state of the electrolytic cell. The data processing unit is configured to calculate equivalent circuit parameters by fitting using the measured data from the power supply characteristic acquisition unit, the input gas characteristic acquisition unit, the electrical characteristic acquisition unit, the output gas characteristic acquisition unit, and the temperature acquisition unit, as well as the simulation data of the equivalent circuit model of the electrolytic cell, and to perform degradation detection based on the information of the equivalent circuit parameters. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows an electrolytic device according to an embodiment. [Figure 2] This figure shows the electrolytic cell in the carbon dioxide electrolysis apparatus of the first embodiment. [Figure 3] This figure shows the degradation detection process using a carbon dioxide electrolysis apparatus according to the first embodiment. [Figure 4] This figure shows the equivalent circuit model of the electrolytic cell in the carbon dioxide electrolysis apparatus of the first embodiment. [Figure 5] This figure shows the equivalent circuit parameters of the equivalent circuit model. [Figure 6]This figure shows the electrolytic cell in a carbon dioxide electrolytic apparatus according to the second embodiment. [Figure 7] This figure shows the equivalent circuit model of the electrolytic cell in the carbon dioxide electrolysis apparatus of the third embodiment. [Figure 8] Figure 7 shows the equivalent circuit parameters of the equivalent circuit model. [Figure 9] This figure shows the equivalent circuit model of the electrolytic cell in the nitrogen electrolysis apparatus of the fourth embodiment. [Figure 10] This figure shows the design process of the electrolytic device according to the fifth embodiment. [Figure 11] This figure shows the measured and simulated data for the CO portion current density JCO and the H2 portion current density JH2 according to Example 1. [Figure 12] This figure shows the measured and simulated data for cell voltage Vcell, cathode potential Vcm, and anode potential Vam according to Example 1. [Figure 13] This figure shows the measured and simulated data for the CO Faraday efficiency FECO and the H2 Faraday efficiency FEH2 according to Example 1. [Figure 14] This figure shows the measured and simulated data of the cathode output gases (CO, H2, and CO2) according to Example 1. [Figure 15] This figure shows the measured and simulated data of the anode output gas (O2 and CO2) according to Example 1. [Modes for carrying out the invention]

[0010] The electrolytic apparatus and electrolytic method of the embodiments will be described below with reference to the drawings. In the embodiments shown below, substantially identical components are denoted by the same reference numerals, and their descriptions may be partially omitted. The drawings are schematic, and the relationship between thickness and planar dimensions, the ratio of the thickness of each part, etc., may differ from those in reality.

[0011] Figure 1 shows an electrolytic apparatus 1 of an embodiment. The electrolytic apparatus 1 shown in Figure 1 comprises an electrolytic cell 2, a power supply control unit 3 that controls the power supplied to the electrolytic cell 2, a power supply characteristic acquisition unit 4 that acquires the characteristics of the supplied power, a gas / electrolyte control unit 5 that controls the gas and electrolyte supplied to the electrolytic cell 2, an input gas characteristic acquisition unit 6 that acquires the characteristics of the supplied input gas, an electrical characteristic acquisition unit 7 that acquires the electrical characteristics of the electrolytic cell 2, an output gas characteristic acquisition unit 8 that acquires the characteristics of the output gas of the electrolytic cell 2, a temperature control unit 9 that controls the temperature of the electrolytic cell 2, a temperature acquisition unit 10 that acquires the temperature of the electrolytic cell 2, a data storage unit 11 that stores data from the power supply characteristic acquisition unit 4, the input gas characteristic acquisition unit 6, the electrical characteristic acquisition unit 7, the output gas characteristic acquisition unit 8, and the temperature acquisition unit 10, a data processing unit 12 that receives data from the data storage unit 11 and processes the transmitted data, and a display unit 13. Each part will be described in detail below.

[0012] The electrolytic cell 2 has a configuration corresponding to the material to be electrolyzed by the electrolytic device 1, but it includes at least a reduction electrode chamber where a gas or liquid containing the material to be reduced is supplied and a reduction electrode is placed, an oxidation electrode chamber where a liquid containing the material to be oxidized is supplied and an oxidation electrode is placed, and a diaphragm provided between the reduction electrode chamber and the oxidation electrode chamber. Examples of materials to be electrolyzed by the electrolytic device 1 include carbon dioxide (CO2), nitrogen (N2), and water (H2O). When CO2 is electrolyzed and reduced, carbon compounds such as carbon monoxide (CO), formic acid (HCOOH), methane (CH4), methanol (CH3OH), ethane (C2H6), ethylene (C2H4), ethanol (C2H5OH), formaldehyde (HCHO), and ethylene glycol (C2H6O2) are produced. Hydrogen (H2) may be generated simultaneously with the reduction reaction of H2O by the reduction reaction of H2O. When N2 is electrolyzed and reduced, ammonia (NH3) is produced.

[0013] (First embodiment) As a first embodiment, a carbon dioxide (CO2) electrolytic apparatus 1 will be described with reference to Figures 1 and 2. Of the electrolytic cells 2 shown in Figure 1, the electrolytic cell 2(2A) for electrolyzing CO2 includes, as shown in Figure 2, a first containment section (container) 22 for containing a first electrolyte 21 containing CO2, a cathode section (reduction electrode chamber) 24 having a reduction electrode (cathode) 23 disposed within the first containment section 22, a second containment section (container) 26 for containing a second electrolyte 25 containing water, an anode section (oxidation electrode chamber) 28 having an oxidation electrode (anode) 27 disposed within the second containment section 26, and a diaphragm 29 disposed between the first containment section 22 and the second containment section 26. The first containment section 22, the second containment section 26, and the diaphragm 29 constitute a reaction vessel 30.

[0014] Reaction vessel 30 contains hydrogen ions (H + ), hydroxide ion (OH - ), bicarbonate ions (HCO3) - ), carbonate ions (CO3 2- The reaction vessel 30 is separated into two chambers, a first containment section 22 and a second containment section 26, by a diaphragm 29 that allows ions such as ions to move. The reaction vessel 30 may be made of, for example, quartz white glass, acrylic resin (PMMA), polystyrene (PS), etc. A light-transmitting material may be used for part of the reaction vessel 5, and a resin material may be used for the remainder. Examples of resin materials include polyether ether ketone (PEEK), polyamide (PA), polyvinylidene fluoride (PVDF), polyacetal (POM) (copolymer), polyphenylene ether (PPE), acrylonitrile-butadiene-styrene copolymer (ABS), polypropylene (PP), polyethylene (PE), etc.

[0015] A reduction electrode 23 is disposed in the first housing portion 22, and further, CO2 is housed. The CO2 is housed in the first housing portion 22, for example, as the first electrolytic solution 21 containing the same. The first electrolytic solution 21 functions as a reduction electrode solution (cathode solution) and contains carbon dioxide (CO2) as a substance to be reduced. Here, as the form of CO2 present in the first electrolytic solution 21, it is not necessary to be in a gaseous state, and it may be dissolved CO2, or may be in the form of carbonate ions (CO3 2- ) or hydrogen carbonate ions (HCO3 - ) or the like. The first electrolytic solution 21 may contain hydrogen ions and is preferably an aqueous solution. An oxidation electrode 27 is disposed in the second housing portion 26, and further, a second electrolytic solution 25 containing water is housed. The second electrolytic solution 25 functions as an oxidation electrode solution (anode solution) and contains, for example, water (H2O), chloride ions (Cl - ), carbonate ions (CO3 2- ), hydrogen carbonate ions (HCO3 - ) or the like as an oxidized substance. The second electrolytic solution 25 may be an aqueous solution of an organic substance such as an alcohol aqueous solution or an amine.

[0016] By changing the amount of water and the electrolytic solution components contained in the first and second electrolytic solutions 21 and 25, the reactivity can be changed, and the selectivity of the substance to be reduced and the ratio of the chemical substances to be produced can be changed. The first and second electrolytic solutions 21 and 25 may contain a redox couple as necessary. Examples of the redox couple include Fe 3+ / Fe 2+ and IO 3- / I - . A gas supply flow path 31 for supplying a raw material gas containing CO2 and a first liquid supply flow path 32 for supplying the first electrolytic solution 21 are connected to the first housing portion 22, and further, a first gas and liquid discharge flow path 33 for discharging the reaction gas and the first electrolytic solution 21 is connected. A second liquid supply flow path 34 for supplying the second electrolytic solution 25 is connected to the second housing portion 26, and further, a second gas and liquid discharge flow path 35 is connected. The first and second housing portions 22 and 26 may have a space portion for housing the gas contained in the reactants and products.

[0017] The pressure inside the first and second containment sections 22 and 26 is preferably set to a pressure at which CO2 does not liquefy, and specifically, it is preferable to adjust it to a range of 0.1 MPa to 6.4 MPa. If the pressure inside the containment sections 22 and 26 is less than 0.1 MPa, the CO2 reduction reaction efficiency may decrease. If the pressure inside the containment sections 22 and 26 exceeds 6.4 MPa, the CO2 will liquefy, and the CO2 reduction reaction efficiency may decrease. Damage to the diaphragm 29 may occur due to the pressure difference between the first containment section 22 and the second containment section 26. Therefore, it is preferable that the difference (differential pressure) between the pressure in the first containment section 22 and the pressure in the second containment section 26 be 1 MPa or less.

[0018] The lower the temperature of electrolytes 21 and 25, the higher the amount of CO2 that can be dissolved. However, from the perspective of CO2 electrolysis, low temperatures are disadvantageous because they increase the solution resistance and the theoretical voltage of the reaction. On the other hand, while higher temperatures of electrolytes 21 and 25 result in a lower amount of dissolved CO2, they are advantageous for CO2 electrolysis. For this reason, the operating temperature conditions of the electrolytic cell 2A are preferably in the medium temperature range, for example, above ambient temperature and below the boiling points of electrolytes 21 and 25. If electrolytes 21 and 25 are aqueous solutions, a temperature of 10°C to 100°C is preferred, and 25°C to 80°C is more preferred. When the first containment section 22 is filled with a raw material gas containing CO2 and the second containment section 26 is filled with water vapor, operation at higher temperatures becomes possible. In that case, the operating temperature is determined considering the heat resistance of components such as the diaphragm 29. When the diaphragm 29 is an ion exchange membrane, the maximum operating temperature is 180°C, and when it is a polymer porous membrane such as Teflon (registered trademark), the maximum temperature is 300°C.

[0019] The first electrolyte 21 and the second electrolyte 25 may contain different substances, or they may contain the same substance and be the same electrolyte. If the first electrolyte 21 and the second electrolyte 25 contain the same substance and the same solvent, they may be considered as a single electrolyte. Furthermore, the pH of the second electrolyte 25 may be higher than that of the first electrolyte 21. This facilitates the movement of ions such as hydrogen ions and hydroxide ions across the membrane 29. In addition, the potential difference between the liquids due to the pH difference allows the oxidation-reduction reaction to proceed effectively.

[0020] The first electrolyte 21 is preferably a solution with a high CO2 absorption rate. The form of CO2 in the first electrolyte 21 is not necessarily limited to a dissolved state; it may also be present as bubbles mixed in the first electrolyte 21. Examples of electrolytes containing CO2 include aqueous solutions containing bicarbonates and carbonates such as lithium bicarbonate (LiHCO3), sodium bicarbonate (NaHCO3), potassium bicarbonate (KHCO3), cesium bicarbonate (CsHCO3), sodium carbonate (Na2CO3), and potassium carbonate (K2CO3), as well as phosphoric acid and boric acid. The electrolyte containing CO2 may also contain alcohols such as methanol, ethanol, and acetone, or it may be an alcohol solution. The first electrolyte 21 may also contain a CO2 absorbent that lowers the reduction potential of CO2, has high ionic conductivity, and absorbs CO2.

[0021] As the second electrolyte 25, a solution using water (H2O), for example, an aqueous solution containing any electrolyte, can be used. This solution is preferably an aqueous solution that promotes the oxidation reaction of water. As an aqueous solution containing an electrolyte, for example, phosphate ions (PO4) can be used. 3- ), borate ions (BO3 3- ), sodium ions (Na + ), potassium ions (K + ), calcium ions (Ca 2+ ), lithium ion (Li + ), cesium ions (Cs + ), magnesium ions (Mg2+ ), chloride ions (Cl - ), bicarbonate ions (HCO3) - ), carbonate ions (CO3 2- ), hydroxide ion (OH - Examples include aqueous solutions containing ) etc.

[0022] The electrolytes 21 and 25 mentioned above include, for example, cations such as imidazolium ions and pyridinium ions, and BF4 - PF6 - Ionic liquids or aqueous solutions thereof, which consist of salts with anions such as ethanolamine and remain liquid over a wide temperature range, can be used. Other electrolytes include amine solutions or aqueous solutions thereof, such as ethanolamine, imidazole, and pyridine. Examples of amines include primary amines, secondary amines, and tertiary amines. These electrolytes may have high ionic conductivity, carbon dioxide absorption properties, and properties that reduce reduction energy.

[0023] Examples of primary amines include methylamine, ethylamine, propylamine, butylamine, pentylamine, and hexylamine. The hydrocarbons of the amines may be substituted with alcohols, halogens, etc. Examples of substituted amine hydrocarbons include methanolamine, ethanolamine, and chloromethylamine. Unsaturated bonds may also be present. The same applies to secondary and tertiary amines.

[0024] Examples of secondary amines include dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, dimethanolamine, diethanolamine, and dipropanolamine. The substituted hydrocarbons may be different. This is also true for tertiary amines. For example, examples of amines with different hydrocarbons include methylethylamine and methylpropylamine.

[0025] Examples of tertiary amines include trimethylamine, triethylamine, tripropylamine, tributylamine, trihexylamine, trimethanolamine, triethanolamine, trippropanolamine, tributanolamine, triexanolamine, methyldiethylamine, and methyldipropylamine.

[0026] Examples of cations in ionic liquids 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.

[0027] The 2-position of the imidazolium ion may be substituted. Examples of cations in which the 2-position of the imidazolium ion is substituted 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.

[0028] Examples of pyridinium ions include methylpyridinium, ethylpyridinium, propylpyridinium, butylpyridinium, pentylpyridinium, and hexylpyridinium. Both the imidazolium ion and the pyridinium ion may be substituted with alkyl groups and may have unsaturated bonds.

[0029] As an anion, fluoride ions (F - ), chloride ions (Cl - ), bromide ions (Br - ), iodide ion (I - ), BF4 - PF6 - CF3COO - CF3SO3 - NO3 - SCN - , (CF3SO2)3C -Examples include bis(trifluoromethoxysulfonyl)imide, bis(trifluoroethoxysulfonyl)imide, and bis(perfluoroethylsulfonyl)imide. Twin ions, in which the cation and anion of an ionic liquid are linked by a hydrocarbon, may also be used. A buffer solution such as potassium phosphate solution may be supplied to the containment sections 22 and 26.

[0030] The diaphragm 29 is made of a membrane that allows for the selective flow of anions or cations. This makes it possible to have electrolytes 21 and 25, which are in contact with the reducing electrode 23 and the oxidizing electrode 27, respectively, containing different substances. Furthermore, the reduction and oxidation reactions can be promoted by differences in ionic strength, pH, etc. The diaphragm 29 can be used to separate the first electrolyte 21 and the second electrolyte 25. The diaphragm 29 may also have the function of allowing some ions contained in the electrolytes 21 and 25 in which both electrodes 23 and 27 are immersed to pass through, that is, the function of shielding one or more types of ions contained in the electrolytes 21 and 25. This makes it possible to have different pH values, etc., between the two electrolytes 21 and 25.

[0031] As the diaphragm 29, for example, ion exchange membranes such as Neosepta (registered trademark) from Astrom, Celemion (registered trademark) from Asahi Glass, Aciplex (registered trademark) from Asahi Kasei, Fumasep (registered trademark) and fumapem (registered trademark) from Fumatech, Nafion (registered trademark), a fluororesin produced 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, and Gore-Tex (registered trademark) from Gore-Tex can be used. Alternatively, the ion exchange membrane may be composed of a membrane with a hydrocarbon as its basic structure, or, in the case of anion exchange, a membrane having an amine group. When there is a pH difference between the first electrolyte 21 and the second electrolyte 25, a bipolar membrane in which a cation exchange membrane and an anion exchange membrane are stacked can be used to maintain the pH of each electrolyte stably.

[0032] In addition to ion exchange membranes, the diaphragm 29 can be made of, for example, silicone resin, perfluoroalkoxyalkane (PFA), perfluoroethylene propene copolymer (FEP), polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), and other fluorine-based resins, polyethersulfone (PES), porous ceramic membranes, packing materials filled with glass filters or agar, insulating porous materials such as zeolites and oxides. Hydrophilic porous membranes are preferably used as the diaphragm 29 because they do not become clogged with air bubbles.

[0033] The reduction electrode 23 is an electrode (cathode) that reduces carbon dioxide (CO2) to produce carbon compounds. The reduction electrode 23 is placed inside the first housing 22 and immersed in the first electrolyte 21. The reduction electrode 23 contains, for example, a reduction catalyst for producing carbon compounds through the reduction reaction of CO2. Examples of reduction catalysts include materials that reduce the activation energy required to reduce CO2. In other words, examples of materials that reduce the overpotential when producing carbon compounds through the reduction reaction of CO2 include materials that reduce the overpotential.

[0034] For example, a metal material or a carbon material can be used as the reduction electrode 23. Examples of metal materials include metals such as gold, aluminum, copper, silver, platinum, palladium, zinc, mercury, indium, nickel, and titanium, as well as alloys containing such metals. Examples of carbon materials include graphene, carbon nanotubes (CNTs), fullerenes, and Ketjenblack. The reduction catalyst is not limited to these; for example, a metal complex such as a Ru complex or Re complex, or an organic molecule having an imidazole or pyridine skeleton may be used. The reduction catalyst may also be a mixture of multiple materials. The reduction electrode 23 may have a structure in which a reduction catalyst, such as a thin film, lattice, particulate, or wire, is provided on a conductive substrate.

[0035] The carbon compounds produced by the reduction reaction at the reduction electrode 23 vary depending on the type of reduction catalyst, and examples include carbon monoxide (CO), formic acid (HCOOH), methane (CH4), methanol (CH3OH), ethane (C2H6), ethylene (C2H4), ethanol (C2H5OH), formaldehyde (HCHO), and ethylene glycol (C2H6O2). At the reduction electrode 23, a side reaction may occur simultaneously with the reduction reaction of carbon dioxide (CO2), generating hydrogen (H2) through the reduction reaction of water (H2O).

[0036] The oxidizing electrode 27 is an electrode (anode) that oxidizes substances and ions in the second electrolyte 25. For example, it oxidizes water (H2O) to produce oxygen or hydrogen peroxide, or chloride ions (Cl - The oxidizing electrode 27 is placed inside the second housing 26 and immersed in the second electrolyte 25. The oxidizing electrode 27 contains an oxidation catalyst for the substance to be oxidized. As the oxidation catalyst, a material is used that reduces the activation energy when oxidizing the substance to be oxidized, in other words, a material that lowers the reaction overpotential.

[0037] Examples of such oxidation catalyst materials include metals such as ruthenium, iridium, platinum, cobalt, nickel, iron, and manganese. Binary metal oxides, ternary metal oxides, and quaternary metal oxides can also be used. 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), and ruthenium oxide (Ru-O). Examples of ternary metal oxides include Ni-Fe-O, Ni-Co-O, La-Co-O, Ni-La-O, and Sr-Fe-O. Examples of quaternary metal oxides include Pb-Ru-Ir-O and La-Sr-Co-O. The oxidation catalyst is not limited to these; metal hydroxides containing cobalt, nickel, iron, manganese, etc., and metal complexes such as Ru complexes and Fe complexes can also be used. Furthermore, a mixture of multiple materials may be used.

[0038] The oxide electrode 27 may be a composite material containing both an oxidation catalyst and a conductive material. Examples of conductive materials include carbon materials such as carbon black, activated carbon, fullerene, carbon nanotubes, graphene, Ketjenblack, 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 Cu, Al, Ti, Ni, Ag, W, Co, and Au; and alloys containing at least one of these metals. The oxide electrode 27 may have a structure in which an oxidation catalyst, such as a thin film, lattice, particulate, or wire-shaped material, is provided on a conductive substrate. Examples of conductive substrates include metallic materials such as titanium, titanium alloys, or stainless steel.

[0039] In the electrolytic apparatus 1 shown in Figure 1, the configuration and operation of the data processing unit 12, etc., will be described. The power supply control unit 3 controls the power that causes the oxidation-reduction reaction in the electrolytic cell 2A and is electrically connected to the reduction electrode 23 and oxidation electrode 27 of the electrolytic cell 2A. A power supply, not shown in the figure, is connected to the power supply control unit 3. Electrical equipment such as DC / AC converters, DC / DC converters, AC / DC converters, inverters, converters, and switches are installed in the power supply control unit 3. The power supply 5 connected to the power supply control unit 3 may be a power supply that converts renewable energy into electrical energy, or it may be a normal commercial power supply or battery, etc. Examples of power supplies using renewable energy include power supplies that convert kinetic energy or potential energy such as wind power, hydropower, geothermal energy, and tidal power into electrical energy, power supplies such as solar cells that have photoelectric conversion elements that convert light energy into electrical energy, power supplies such as fuel cells and storage batteries that convert chemical energy into electrical energy, and power supplies that convert vibration energy such as sound into electrical energy.

[0040] The power supply characteristic acquisition unit 4 acquires the power supplied to the electrolytic cell 2A, i.e., the voltage and current. The power supply characteristics acquired by the power supply characteristic acquisition unit 4 are transmitted to the data storage unit 11 via a signal line. The power supply control unit 3 and the power supply characteristic acquisition unit 4 may be configured independently or as an integrated unit.

[0041] The gas / electrolyte control unit 5 controls the flow rate of the CO2-containing gas and the electrolyte input to the electrolytic cell 2A. It may also control the dew point, temperature, and pressure of the gas, and the pressure, temperature, composition, and pH of the electrolyte. The input gas characteristic acquisition unit 6 acquires the flow rate and composition of the CO2-containing gas input to the electrolytic cell 2A. It may also have a function to acquire characteristics such as the dew point, temperature, and pressure of the CO2-containing gas. The acquired input gas characteristics are transmitted to the data storage unit 11 via a signal line. The gas / electrolyte control unit 5 and the input gas characteristic acquisition unit 6 may be configured independently or as an integrated unit.

[0042] The electrical characteristics acquisition unit 7 acquires electrical characteristics of the electrolytic cell 2A, such as the cell voltage and cell current. To improve the accuracy of equivalent circuit parameters, it is preferable to incorporate a reference electrode into the electrolytic cell 2A and acquire the potentials of the cathode 23 and anode 27 relative to the reference electrode. It may also have a function to acquire the impedance of the electrolytic cell 2A. The electrical characteristics are transmitted to the data storage unit 11 via a signal line.

[0043] The output gas characteristics acquisition unit 8 acquires the flow rate of the gas output from the cathode 23 side of the electrolytic cell 2A, and the concentrations of CO2 and various gases produced by the CO2 reduction reaction. It may also have a function to acquire the concentrations of H2 and other gases produced by side reactions. Furthermore, it may have a function to acquire the flow rate of O2 and CO2 output from the anode 27 side, gas concentrations, etc. The output gas characteristics are transmitted to the data storage unit 11 via a signal line.

[0044] The temperature control unit 9 controls the temperature of the electrolytic cell 2A to a predetermined value and has the function of controlling the heating of the heater incorporated in the electrolytic cell 2A and the flow of refrigerant to the cooling water channel. The temperature acquisition unit 10 acquires the temperature of the electrolytic cell 2A. The acquired temperature is transmitted to the data storage unit 11 via a signal line. The temperature control unit 9 and the temperature acquisition unit 10 may be configured independently or as an integrated unit.

[0045] The data storage unit 11 includes control equipment such as a computer and has the function of storing data on a recording medium such as memory, hard disk, or SSD, as well as a data transmission and reception function. The display unit is a display and has the function of displaying information sent from the data storage unit and the degradation detection unit. The data storage unit and the display unit may be configured independently or as an integrated configuration such as a computer.

[0046] The data processing unit 12 is equipped with a computer such as a PC or microcontroller, and calculates an equivalent circuit model and equivalent circuit parameters based on the data transmitted from the data storage unit 11. The data processing unit 12 estimates the location of deterioration and calculates the degree of deterioration based on the equivalent circuit parameters. Furthermore, based on the information on the location of deterioration and the degree of deterioration, it makes a decision on whether to continue operation of the CO2 electrolytic cell 2A, perform a refresh operation, or stop operation, and sends commands to the power supply control unit 3, the gas / electrolyte control unit 5, and the temperature control unit 9. The data processing unit 12 may be installed near the electrolytic cell 2A, or it may be installed in the cloud for remote diagnosis. By installing the data processing unit 12 in the cloud, the accumulated data of electrolytic cells 2A installed in various locations can be integrated and managed, improving the accuracy of deterioration detection. For this reason, it is preferable to install the data processing unit 12 in the cloud.

[0047] Next, the method for detecting the degradation of the electrolytic device 1 will be explained with reference to Figure 3. First, the equivalent circuit model and equivalent circuit parameters of the electrolytic cell 2A during its design are created in a database and stored in the data processing unit 12. Alternatively, a trial run may be performed on the electrolytic cell 2A using the power supply control unit 3 and the gas / electrolyte control unit 5 to calculate the equivalent circuit model and obtain the equivalent circuit parameters before full operation and then create a database (S1). Full operation of the electrolytic cell (or electrolytic cell stack) 2 is started, and the power supply characteristics, input gas characteristics, electrical characteristics of the electrolytic cell 2A, output gas characteristics, and temperature are obtained and stored in the data storage unit 11 (S2). This data is transmitted to the data processing unit 12, where calculations are performed to calculate the equivalent circuit model and equivalent circuit parameters (S3).

[0048] In the data processing unit 12, the equivalent circuit model and equivalent circuit parameters acquired during the design phase or before actual operation in S1 are compared with the equivalent circuit model and equivalent circuit parameters during actual operation to estimate the location of deterioration and calculate the degree of deterioration. Furthermore, the lifespan until shutdown is predicted from the progression of the degree of deterioration (S4). A determination is made as to whether the degree of deterioration exceeds the shutdown criterion (S5), and if it exceeds the shutdown criterion, the actual operation of the electrolytic cell (or electrolytic cell stack) 2 is stopped (S6). During shutdown, maintenance or replacement of the electrolytic cell 2A is performed according to the location of deterioration (S7). Various characteristic data stored in the data storage unit 11 in S2, the equivalent circuit model and equivalent circuit parameters calculated in S3, the location of deterioration and degree of deterioration calculated in S4, and the lifespan until shutdown are transmitted to the display unit 13 for display (S8).

[0049] Next, the operation of the CO2 electrolysis apparatus 1 will be explained. Here, an aqueous solution containing CO2 and an aqueous solution of potassium bicarbonate (KHCO3) are used as the electrolytes 21 and 25, and CO2 is reduced to mainly produce carbon monoxide (CO), as well as water (H2O) or hydroxide ions (OH). - This section describes the case where CO2 is oxidized to produce oxygen. The reduction reaction of CO2 is not limited to the reaction of producing CO, but also C x H y O z The reaction may involve the production of carbon compounds such as formic acid (HCOOH), methane (CH4), methanol (CH3OH), ethane (C2H6), ethylene (C2H4), ethanol (C2H5OH), formaldehyde (HCHO), and ethylene glycol (C2H6O2).

[0050] When a voltage greater than the electrolytic voltage is applied between the reducing electrode (cathode) 23 and the oxidizing electrode (anode) 27, a reduction reaction of CO2 occurs near the reducing electrode 23 in contact with the first electrolyte 21. As shown in equation (1) below, electrons (e) supplied from the power source... - ) reduces the CO2 contained in the first electrolyte 21 to CO and OH - and are generated. As shown in equations (2) and (3), the generated OH -Some of it reacts with CO2 to form bicarbonate ions (HCO3). - ) and carbonate ions (CO3 2- ) is generated. Due to the voltage between the reducing electrode 23 and the oxidizing electrode 27, OH is released through the diaphragm 29. - , HCO3 - , and CO3 2- A portion of it moves into the second electrolyte 25. 2CO2 + 2H2O + 4e - → 2CO + 4OH - …(1) 2CO2 + 2OH - → 2HCO3 - …(2) 2HCO3 - +2OH - → CO3 2- +H2O …(3)

[0051] Near the oxidation electrode 27 in contact with the second electrolyte 25, an oxidation reaction of water (H2O) occurs. As shown in equation (4) below, an oxidation reaction of H2O contained in the second electrolyte 25 occurs, electrons are lost, and oxygen (O2) and hydrogen ions (H2O) are produced. + ) and are generated. 2H2O → 4H + +O2+4e - …(4) As shown in equations (5) to (7) below, the generated hydrogen ions (H + ) part of which is hydroxide ions (OH) that have moved across the diaphragm 29 - ), bicarbonate ions (HCO3) - ), carbonate ions (CO3 2- It reacts with a portion of the ions to produce H2O and CO2. 2H + +CO3 2- → H2O + CO2…(5) 2H + +2HCO3 - → 2H2O + 2CO2…(6) H + +OH - → H2O …(7)

[0052] In the above, the OH at the reducing electrode 23- The operation was explained based on the generation of H, but as described below, H at the oxidation electrode 27 + The operation may also be based on the generation and movement of electrons. When a voltage greater than the electrolytic voltage is applied between the reducing electrode 23 and the oxidizing electrode 27, an oxidation reaction of water (H2O) occurs near the oxidizing electrode 27 in contact with the second electrolyte 25. As shown in equation (8) below, an oxidation reaction of H2O contained in the second electrolyte 25 occurs, electrons are lost, and oxygen (O2) and hydrogen ions (H2O) are produced. + ) and are generated. The generated hydrogen ions (H + A portion of the ) moves into the first electrolyte 21 via the diaphragm 29. 2H2O → 4H + +O2+4e - …(8)

[0053] Hydrogen ions (H) generated on the oxidizing electrode 27 side + As the electrons reach the vicinity of the reduction electrode 23, electrons (e) are sent from the power supply to the reduction electrode 23. - When ) is supplied, a reduction reaction of carbon dioxide (CO2) occurs. As shown in equation (9) below, hydrogen ions (H) move to the vicinity of the reduction electrode 23. + ) and electrons (e) supplied from the power source - ) reduces the CO2 contained in the first electrolyte 21, generating carbon monoxide (CO). 2CO2 + 4H + +4e - → 2CO + 2H2O …(9)

[0054] The data storage unit 11 shown in FIG. 1 is configured to store each data from the power supply characteristics acquisition unit 4, the input gas characteristics acquisition unit 6, the electrical characteristics acquisition unit 7, the output gas characteristics acquisition unit 8, and the temperature acquisition unit 10. The data processing unit 12 is configured such that each of the above data is sent from the data storage unit 11 and the state of the electrolytic cell 2A is determined by processing each data. That is, in the data processing unit 12, an equivalent circuit model and equivalent circuit parameters of the electrolytic cell 2A are calculated based on the processing results of each data, and the state of the electrolytic cell 2A is determined based on the calculation results of the equivalent circuit model and equivalent circuit parameters. Specific examples of the state determination of the electrolytic cell 2A include estimating a deterioration location or the like of the electrolytic cell 2A, and further calculating a degree of deterioration of the deterioration location.

[0055] Next, a method for calculating an equivalent circuit model and equivalent circuit parameters by the data processing unit 12, a method for estimating a deterioration location, and a method for calculating a degree of deterioration will be described with reference to FIG. 4. FIG. 4 is an example of an equivalent circuit model of the CO2 electrolytic cell 2A. As an example, a case where a CO2 reduction product substance (C x H y O z ) is generated by the reduction reaction of CO2 will be described. When CO is generated, C x H y O z may be replaced with CO. In the cathode part 24 of the equivalent circuit model, a C x H y O z generation part and a H2 generation part of a side reaction are connected in parallel, and a cathode resistance is connected in series. The diaphragm part 29 has a diaphragm resistance. In the anode part 28, an O2 generation part and an anode resistance are connected in series. The cathode part 24, the diaphragm part 29, and the anode part 28 are connected in series.

[0056] C x H y O z The current densities J A of the generation part, the H2 generation part, and the O2 generation part are represented by, for example, the Tafel formula of the following formula (10).

[0057]

Equation

[0058] When the CO2 flow rate introduced into the CO2 electrolysis cell 2A is sufficiently large, Equation (10) can be used. When considering that the CO2 flow rate is small and the generation current density of C x H y O z is limited by the CO2 flow rate, that is, there is a limit, then the current density J x H y O z of the generation section is represented by a relational expression including the Tafel formula of Equation (10) and the CxHyOz generation limiting current density J CxHyOz ER include low CO2 as shown in the following Equation (11). Here, f1 represents that it is a function. CxHyOz ER, L as variables.

[0059]

Equation

[0060] As shown in equations (2), (3), (5), and (6), the CO2 on the cathode side is HCO3 - CO3 2- It is converted to CO2 and moves to the anode side, where it is converted back to CO2. The flow rate of CO2 moving from the cathode side to the anode side due to this ion movement is called flow. CO2 from cathode to anode Expressed as, C x H y O z The CO2 flow rate that can be used for generation is reduced by the amount of CO2 flowing from the cathode side to the anode side, so C x H y O z Generation limit current density J CxHyOz ER, L As shown in equation (12) below, the CO2 flow rate introduced into the cathode is... CO2 cathode, input And the CO2 flow rate moving from the cathode side to the anode side. CO2 from cathode to anode This can be expressed as a relational expression containing the variable f2. Here, f2 represents a function.

[0061]

number

[0062] The current I flowing through the electrolytic cell shown in Figure 4 cell C x H y O z The current J used in the generation CxHyOz ER include low CO2 (J CxHyOz ER (or is also acceptable), and the current J used to generate H2 HER The following relationships exist.

[0063]

number

[0064]

number

[0065] Next, Figure 5 shows the equivalent circuit parameters of the equivalent circuit model shown in Figure 4. These equivalent circuit parameters are calculated by fitting using one or more of the following data collected before actual operation: supply power characteristics, input gas characteristics, electrical characteristics of the CO2 electrolytic cell, output gas characteristics, and temperature. Spreadsheet software or a circuit simulator can be used for fitting. During actual operation, the equivalent circuit parameters are periodically calculated using the data sent from the data storage unit 11 to the data processing unit 12, and by comparing the equivalent circuit parameters before actual operation or during design with the equivalent circuit parameters during actual operation, it is possible to estimate the locations of degradation.

[0066] Furthermore, the degree of degradation D can be calculated for each equivalent circuit parameter based on equation (15) shown below.

[0067]

number

[0068]

number

[0069] (Second embodiment) Next, the configuration and degradation detection system of the carbon dioxide electrolytic apparatus of the second embodiment will be described with reference to Figures 1 and 6. The degradation detection system of the carbon dioxide electrolytic apparatus 1 of the second embodiment is the same as the degradation detection system of the first embodiment. In the carbon dioxide electrolytic apparatus 1 of the second embodiment, the contact method of the gas containing CO2 (sometimes simply referred to as CO2 gas) of the electrolytic cell 2B with the reduction electrode 23, and the contact method of the second electrolyte (anode solution) containing water with the oxidation electrode 27 differ from that of the electrolytic cell 2A of the first embodiment. The electrolytic cell 2B of the carbon dioxide electrolytic apparatus 1 of the second embodiment has a different configuration from the electrolytic cell 2A of the first embodiment. The configuration of other parts, such as the reduction electrode 23, oxidation electrode 27, diaphragm 29, and second electrolyte, are the same as those of the first embodiment.

[0070] As shown in Figure 9, the electrolytic cell 2B according to the second embodiment comprises a reduction electrode 23, an oxidation electrode 27, a diaphragm 29, a first flow path 36 for circulating a gas containing CO2, a second flow path 37 for circulating a second electrolyte (anode solution) containing water, a first current collector plate 38 electrically connected to the reduction electrode 23, and a second current collector plate 39 electrically connected to the oxidation electrode 27. The reduction electrode 23 and the first flow path 31 facing it constitute a cathode section (reduction electrode chamber) 24. The oxidation electrode 27 and the second flow path 32 facing it constitute an anode section (oxidation electrode chamber) 28.

[0071] In the second embodiment, instead of a gas containing CO2, a first electrolyte containing CO2 may be circulated through the first flow path 36. Alternatively, a flow path (not shown) may be provided between the reducing electrode 23 and the diaphragm 29, and a gas containing CO2 may be circulated through the first flow path 36, while the first electrolyte may be circulated through the flow path between the reducing electrode 23 and the diaphragm 29. In this case, the first electrolyte used may or may not contain CO2. Furthermore, instead of the second electrolyte containing water, a gas containing water vapor may be used.

[0072] During operation of electrolytic cell 2B, the reduction products of CO2 and components of the second electrolyte that have moved to the reduction electrode 23 side may solidify and precipitate in the first channel 36, potentially blocking the first channel 36 and stopping the supply of CO2-containing gas. Therefore, it is preferable that moisture be present in the CO2-containing gas to suppress the formation of precipitates. On the other hand, if the amount of moisture in the CO2-containing gas is too high, a large amount of moisture will be supplied to the catalyst surface inside the reduction electrode 23, making hydrogen generation more likely, which is undesirable. Therefore, the amount of moisture in the CO2-containing gas is preferably a relative humidity of 20 to 90%, and more preferably 30 to 70%.

[0073] The first flow path 36 is connected to a first supply flow path 31 for supplying gas containing CO2 and a first discharge flow path 33 for discharging the generated gas. The second flow path 37 is connected to a second supply flow path 34 for supplying an electrolyte containing water and a second discharge flow path 35. The first flow path 36 is positioned to face the reduction electrode 23. The first flow path 36 is connected to the first supply flow path 31, from which gas containing CO2 is supplied. The first flow path 36 is configured to come into contact with the reduction electrode 23 as the CO2 gas or the first electrolyte (cathode solution) flows through it. The CO2 gas or CO2 in the cathode solution that has passed through the reduction electrode 23 is reduced by the reduction electrode 23. The gas or solution containing the CO2 reduction reaction product is discharged from the first discharge flow path 33.

[0074] The second channel 37 is positioned to face the oxidation electrode 27. A solution tank (not shown) is connected to the second channel 37, and the anode solution is configured to come into contact with the oxidation electrode 27 as it flows through the second channel 37. The H2O in the anode solution that has passed through the oxidation electrode 27 is oxidized by the oxidation electrode 27.

[0075] In the degradation detection system for the carbon dioxide electrolysis apparatus of the second embodiment, the equivalent circuit model shown in Figure 4 can be applied, similar to the first embodiment, and the equivalent circuit parameters shown in Figure 5 are calculated by fitting them. During actual operation, the equivalent circuit parameters are periodically calculated using the data sent from the data storage unit 11 to the data processing unit 12, and the location of degradation can be estimated by comparing the equivalent circuit parameters before actual operation or at the design stage with the equivalent circuit parameters during actual operation. Furthermore, a judgment criterion can be set for the degradation degree D, and decisions can be made regarding shutdown, refresh operation, or maintenance.

[0076] (Third embodiment) The configuration and degradation detection system of the carbon dioxide electrolysis apparatus of the third embodiment will be described with reference to Figures 1, 6, and 7. The carbon dioxide electrolysis apparatus of the third embodiment has two equivalent circuits for H2 production. The electrolysis apparatus of the third embodiment has a configuration and degradation detection system similar to that of the electrolysis apparatus of the first or second embodiment. The electrolysis cell according to the third embodiment has a configuration similar to, for example, the electrolysis cell according to the second embodiment. However, the data processing according to the third embodiment is different. department The equivalent circuit model used is different from the equivalent circuit model according to the first embodiment. The equivalent circuit model of the data processing unit 12 according to the third embodiment will be described with reference to Figure 7.

[0077] Figure 7 shows an example of an equivalent circuit model of a carbon dioxide electrolytic cell. Here, the CO2 reduction reaction is carried out by C x H y O z Let's explain using the case where CO is produced as an example. x H y O z Simply replace with CO. In the cathode section of the equivalent circuit model, C x H y O z The H2 generation section and the two H2 generation sections for side reactions are connected in parallel, and the cathode resistor is connected in series. The H2 generation section has an H2 generation section (low current density) that is applied to the low current density region and an H2 generation section (high current density) that is applied to the high current density region, and these are connected in parallel. The diaphragm section is a diaphragm resistor. In the anode section, the O2 generation section and the anode resistor are connected in series. The cathode section, diaphragm section and anode section are connected in series.

[0078] In the parameters of the Tafel equation in equation (10), the subscript A is used as HER low when it is an H2 generation unit (low current density) and as HER high when it is an H2 generation unit (high current density). Figure 8 shows the equivalent circuit parameters of the equivalent circuit model according to the third embodiment. These equivalent circuit parameters are calculated by fitting using the supply power characteristics, input gas characteristics, electrical characteristics of the electrolytic cell, output gas characteristics, and temperature collected before actual operation. Spreadsheet software or a circuit simulator can be used for fitting. During actual operation, the equivalent circuit parameters are periodically calculated using the data sent from the data storage unit 11 to the data processing unit 12, and the deteriorated areas can be estimated by comparing the equivalent circuit parameters before actual operation or at the design stage with the equivalent circuit parameters during actual operation. Furthermore, it becomes possible to set judgment criteria for the degree of deterioration D and make decisions regarding shutdown, refresh operation, and maintenance.

[0079] (Fourth embodiment) The configuration of the electrolytic apparatus and the degradation detection system of the fourth embodiment will be described with reference to Figures 1, 2, 6, and 9. The electrolytic apparatus of the fourth embodiment is a device that produces ammonia (NH3) by electrolysis and reduction of nitrogen (N2). However, although the electrolytic material and electrolytic product differ, the configuration of the electrolytic apparatus of the fourth embodiment is the same as that of the electrolytic apparatus 1 of the first embodiment shown in Figure 1. Furthermore, in the electrolytic apparatus of the fourth embodiment, the electrolytic cell is the same as that of the electrolytic cell 2A shown in Figure 2. In the electrolytic apparatus of the fourth embodiment, an electrolytic cell having a configuration similar to that of the electrolytic cell 2B shown in Figure 6 may also be used.

[0080] In the fourth embodiment, the substance reduced in the cathode of the electrolytic cell shown in Figure 2 is nitrogen (N2), and the equivalent circuit model differs from that of the first embodiment. The first electrolyte contained in the cathode contains N2 as the electrolytic material. Alternatively, in the electrolytic cell shown in Figure 6, N2 gas may be supplied to the cathode as the electrolytic material.

[0081] When reducing nitrogen (N2), the first electrolyte preferably contains an ammonia-producing catalyst and a reducing agent that reduce N2 to produce ammonia, separately from the electrochemical reaction. As the reducing agent, lanthanide metal halides (II) are used. Examples of lanthanide metals include lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), derbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu), with Sm being preferred. Examples of halogens include chlorine (Cl), bromine (Br), and iodine (I), with iodine being preferred. As the lanthanide metal halide (II), samarium(II) iodide (SmI2) is more preferred.

[0082] Ammonia production catalysts promote the production of ammonia from nitrogen in the presence of a reducing agent. For example, molybdenum complexes are used, but are not limited to them. Examples of ammonia production catalysts include the molybdenum complexes (A) to (D) shown below.

[0083] A first example is a molybdenum complex having (A) N,N-bis(dialkylphosphinomethyl)dihydrobenzimidazolidene as the PCP ligand (where the two alkyl groups may be the same or different, and at least one hydrogen atom of the benzene ring may be substituted with an alkyl group, an alkoxy group, or a halogen atom).

[0084] A second example is a molybdenum complex having (B) 2,6-bis(dialkylphosphinomethyl)pyridine as the PNP ligand (where the two alkyl groups may be the same or different, and at least one hydrogen atom of the pyridine ring may be substituted with an alkyl group, an alkoxy group, or a halogen atom).

[0085] A third example is a molybdenum complex having a bis(dialkylphosphinomethyl)arylphosphine (where the two alkyl groups may be the same or different) as the (C)PPP ligand.

[0086] A fourth example is a molybdenum complex represented as (D)trans-Mo(N2)2(R1R2R3P)4 (where R1, R2, and R3 may be the same or different alkyl or aryl groups, and two R3s may be linked together to form an alkylene chain).

[0087] In the molybdenum complex described above, the alkyl group may be a linear or branched alkyl group such as a methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, and their structural isomers, or a cyclic alkyl group such as a cyclopropyl group, cyclobutyl group, cyclopentyl group, or cyclohexyl group. The number of carbon atoms in the alkyl group is preferably 1 to 12, and more preferably 1 to 6. The alkoxy group may be a linear or branched alkoxy group such as a methoxy group, ethoxy group, propoxy group, butoxy group, pentoxy group, hexyloxy group, and their structural isomers, or a cyclic alkoxy group such as a cyclopropoxy group, cyclobutoxy group, cyclopentoxy group, or cyclohexyloxy group. The number of carbon atoms in the alkoxy group is preferably 1 to 12, and more preferably 1 to 6. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine.

[0088] The amount of ammonia-generating catalyst used can be appropriately selected within the range of 0.00001 to 0.1 mol / L equivalent relative to the electrolyte, preferably 0.0001 to 0.05 mol / L equivalent, and more preferably 0.0005 to 0.01 mol / L equivalent.

[0089] Next, we will explain the operation of the electrolytic apparatus when ammonia is produced by the N2 reduction reaction. When a voltage greater than the electrolytic voltage is applied between the reducing electrode (cathode) and the oxidizing electrode (anode), the oxidizing electrode electrochemically reacts with water (H2O) or hydroxide ions (OH) in the second electrolyte. - An oxidation reaction occurs. For example, when the hydrogen ion concentration of the second electrolyte is 7 or less (pH ≤ 7), H2O is oxidized to O2 and H based on the following equation (17). + Furthermore, if the hydrogen ion concentration of the second electrolyte is greater than 7 (pH>7), OH is generated based on the following formula (18). - It is oxidized to produce O2 and H2O. 3H2O → 3 / 2O2 + 6H + +6e - …(17) 6OH - → 3 / 2O2 + 3H2O + 6e - …(18)

[0090] In the first containment section (first electrolytic cell) 22, separate from the electrochemical reaction, nitrogen (N2) in the first electrolyte is reduced by an ammonia-producing catalyst and a reducing agent to produce ammonia (NH3). When SmI2 is used as the reducing agent, for example, the N2 in the first electrolyte is reduced to produce ammonia (NH3) based on the following formula (19). N2+6SmI2+6H2O → 2NH3+6SmI2(OH) …(19)

[0091] As shown in equation (19) above, the SmI2 acting as a reducing agent is oxidized by the generation of NH3, and in that state, its function as a reducing agent is impaired. That is, in a first electrolytic cell that does not have a reducing electrode that generates an electrochemical reduction reaction, if the reduction reaction of N2 in the first electrolyte is generated, the reduction reaction of N2 stops and the generation of NH3 ends when the amount of reducing agent initially introduced into the first electrolytic cell is consumed by the reduction reaction of N2. In contrast to this, the electrolytic apparatus of the embodiment has a reducing electrode that generates an electrochemical reduction reaction in the first electrolytic cell, so that the reducing agent oxidized by the reducing electrode, i.e., SmI2(OH), can be reduced and regenerated based on the following equation (20). Therefore, the reduction reaction of N2 can be continuously sustained. The amount of reducing agent used is preferably 0.01 to 2 mol / L, and more preferably 0.1 to 1 mol / L, relative to the first electrolyte in order to promote the reaction with the ammonia generation catalyst. 6SmI2(OH)+6e - → 6SmI2+6OH - …(20)

[0092] Figure 9 is an equivalent circuit model of an electrolytic cell that generates NH3 using SmI2 as a reducing agent. As shown in equation (20) above, SmI2(OH) is electrochemically regenerated back into SmI2. Therefore, in the cathode section of the equivalent circuit model, the SmI2 regeneration section and the H2 generation section of the side reaction are connected in parallel. The current density of the SmI2 regeneration section is expressed by the Tafel equation in equation (10) above. The subscript A in equation (10) is written as SmI2RR (SmI2 regeneration reaction).

[0093] (Fifth embodiment) The design method for the electrolytic apparatus and electrolytic system of the fifth embodiment will be described with reference to Figure 10. The electrolytic system of the fifth embodiment is the same as the electrolytic systems of the first to second embodiments. In the design method for the electrolytic system of the fifth embodiment, the system design is performed using the equivalent circuit models and equivalent circuit parameters of the first to fourth embodiments.

[0094] First, a reference electrolytic cell (reference electrolytic cell) is operated to acquire the power supply characteristics, input gas characteristics, electrical characteristics, output gas characteristics, and temperature characteristics, and the measured data is stored in the data storage unit (S1). When acquiring this measured data, it is preferable to perform an aging operation in which current is applied in advance to stabilize the cell characteristics. Since a longer aging operation time stabilizes the cell characteristics, it is preferable to have an aging operation time of 1 hour or more, and more preferably 2 hours or more. In the data processing unit, a candidate equivalent circuit model of the electrolytic cell is selected (S2).

[0095] In the data processing unit, the parameters of the equivalent circuit model are calculated by fitting so that the squared error between the measured data of the reference electrolytic cell in S1 and the simulation data of the equivalent circuit model is minimized (S3). A criterion for determining the squared error between the measured data and the simulation data of the equivalent circuit model is set in advance, and if it is greater than the criterion, the candidate equivalent circuit model in S2 is changed. If the squared error is smaller than the criterion, the equivalent circuit model in S2 is judged to be valid (S4). The electrolytic system is designed using the equivalent circuit model and its parameters that have been judged to be valid (S5). [Examples]

[0096] Next, we will describe the examples and their evaluation results.

[0097] (Example 1) A carbon dioxide electrolytic cell, whose configuration is shown in Figure 6, was manufactured. The carbon dioxide electrolytic cell was operated using the degradation detection system for the electrolytic device shown in Figure 1. As the reduction electrode used in the carbon dioxide electrolytic cell, carbon particles coated with gold nanoparticles supported on carbon paper were used. The average particle size of the gold nanoparticles was 2 nm, and the supported amount was 10 mass%. As the oxidation electrode, an electrode coated with IrO2 nanoparticles on a Ti mesh was used. An anion exchange membrane was used as the diaphragm. The electrode area of ​​both the reduction electrode and the oxidation electrode was 16 cm². 2The material was cut and used in this manner. Similar to the carbon dioxide electrolytic cell shown in Figure 6, the first current collector plate, first channel, reduction electrode, diaphragm, oxidation electrode, second channel, and second current collector plate were stacked from left to right in that order, and sandwiched between insulating plates, cooling water channels, and support plates (not shown) to form a carbon dioxide electrolytic cell. In addition, to easily monitor the reduction electrode potential and oxidation electrode potential, a Pt foil (not shown) was placed in contact with the diaphragm on the reduction electrode side as a reference electrode.

[0098] Using a gas / electrolyte control unit, CO2 was introduced into the first channel of the carbon dioxide electrolytic cell at a flow rate of 80 sccm, and a 0.1 M KHCO3 electrolyte solution was introduced into the second channel at a flow rate of 10 mL / min. The carbon dioxide electrolytic cell was also temperature-controlled to 40°C using a temperature control unit and temperature acquisition unit, with a heater and cooling water channel (not shown) in close contact with the carbon dioxide electrolytic cell. A potentiostat / galvanostat integrating these functions was used as the power supply control unit, power supply acquisition unit, and electrical characteristic acquisition unit. A volumetric flow meter and a gas chromatography analyzer were used as the output gas acquisition unit.

[0099] Current was passed through a carbon dioxide electrolytic cell, and the current density dependence of the supplied power characteristics (supplied current and voltage), input gas characteristics (gas flow rate input to the cathode), cell temperature, electrical characteristics (cell current, cell voltage, cathode potential, anode potential, cell resistance), and output gas characteristics (gas flow rate output from the cathode and anode, various gas concentrations) was obtained. At the cathode, CO was produced by the CO2 reduction reaction, and H2 was produced by a side reaction. At the anode, O2 was produced by the oxidation reaction of water. Since the behavior of the H2 production reaction differed between the low current density region and the high current density region, an equivalent circuit model was used, as shown in Figure 7, in which a CO production unit and two H2 production units were connected in parallel.

[0100] The CO partial current density (current density contributing to CO generation) and the H2 partial current density (current density contributing to H2 generation) are calculated from the gas flow rate output from the cathode and the gas concentrations of CO and H2, and as shown in Figures 11 and 12, the CO partial current density J CO , H2 partial current density J H2, cell voltage V cell , cathode potential V cm , anode potential V am The equivalent circuit parameters were determined to minimize the error between the measured data and the simulation data. As shown in Figures 13, 14, and 15, the CO Faraday efficiency (FE) CO ), H2 Faraday efficiency (FE H2 The simulation data for the cathode output gas (CO, H2, and CO2) and anode output gas (O2 and CO2) reproduce the measured data well. Therefore, it is possible to detect degradation by examining the changes in equivalent circuit parameters during operation using the equivalent circuit model in Figure 7.

[0101] A technical proposal for the above-described embodiment is provided below. (Technical proposal 1) An electrolytic cell comprising a cathode section to which a gas or liquid containing the substance to be reduced is supplied and a reducing electrode is positioned, an anode section to which a liquid containing the substance to be oxidized is supplied and an oxidizing electrode is positioned, and a diaphragm provided between the cathode section and the anode section, A power supply characteristic acquisition unit that acquires the characteristics of the power supplied to the electrolytic cell, An input gas characteristic acquisition unit that acquires the characteristics of the gas input to the electrolytic cell, An electrical characteristics acquisition unit for acquiring the electrical characteristics of the electrolytic cell, An output gas characteristic acquisition unit for acquiring the characteristics of the output gas of the electrolytic cell, A temperature control unit that controls the temperature of the electrolytic cell, A temperature acquisition unit that acquires the temperature of the electrolytic cell, A data storage unit that stores data from the power supply characteristics acquisition unit, the input gas characteristics acquisition unit, the electrical characteristics acquisition unit, the output gas characteristics acquisition unit, and the temperature acquisition unit, The data is sent from the data storage unit, and a data processing unit processes the data to determine the state of the electrolytic cell. An electrolytic device equipped with the following. (Technical proposal 2) The electrolytic apparatus according to Technical Proposal 1, wherein the data processing unit is configured to calculate equivalent circuit parameters by fitting using at least one measured data from the power supply characteristic acquisition unit, the input gas characteristic acquisition unit, the electrical characteristic acquisition unit, the output gas characteristic acquisition unit, and the temperature acquisition unit, and simulation data of the equivalent circuit model of the electrolytic cell, and to perform degradation detection based on the information of the equivalent circuit parameters. (Technical proposal 3) The electrolytic apparatus according to Technical Proposal 2, wherein the data processing unit is configured to estimate the location of deterioration by comparing the equivalent circuit parameters before actual operation or during design with the equivalent circuit parameters during actual operation. (Technical proposal 4) The electrolytic apparatus according to Technical Proposal 3, wherein the data processing unit is configured to determine the degree of deterioration of the equivalent circuit parameters, which are expressed as [(equivalent circuit parameters during actual operation) - (equivalent circuit parameters before actual operation or at the time of design)] / (equivalent circuit parameters before actual operation or at the time of design), and to determine whether to stop the operation of the electrolytic cell by setting a judgment criterion for the degree of deterioration. (Technical proposal 5) The electrolytic apparatus according to any one of Technical Proposals 2 to 4, wherein the data processing unit comprises, as the equivalent circuit model, a carbon dioxide reducing substance generating unit and a hydrogen generating unit connected in parallel, a cathode unit with a series resistor connected in series, a diaphragm unit, and an anode unit with an oxygen generating unit and a series resistor connected in series, and is configured to calculate an equivalent circuit in which the cathode unit, the diaphragm unit and the anode unit are connected in series. (Technical proposal 6) The electrolytic apparatus according to Technical Proposal 5, wherein the data processing unit is configured to calculate the current density of the carbon dioxide reducing substance generation section of the equivalent circuit model based on a relational expression that includes the current density expressed by the Tafel equation and the limiting current density for the generation of the carbon dioxide reducing substance as variables. (Technical proposal 7) The electrolytic apparatus according to Technical Proposal 6, wherein the data processing unit is configured to calculate the limiting current density for the production of the carbon dioxide reducing substance based on a relational expression that includes the flow rate of the substance to be reduced introduced into the cathode and the flow rate of the substance to be reduced moving from the cathode to the anode as variables. (Technical proposal 8) The electrolytic apparatus according to any one of Technical Proposals 1 to 7, wherein the data processing unit is installed in the cloud and configured to remotely determine the state of the electrolytic cell. (Technical proposal 9) The electrolytic apparatus according to any one of Technical Proposals 1 to 8, wherein the electrolytic cell is configured to produce a carbon compound when carbon dioxide is supplied as the reduced substance, or to produce ammonia when nitrogen is supplied as the reduced substance. (Technical proposal 10) A step of operating an electrolytic cell comprising a cathode section where a reducing electrode is located, an anode section where an oxidizing electrode is located, and a diaphragm provided between the cathode section and the anode section, by supplying a gas or liquid containing the substance to be reduced to the cathode section and supplying a liquid containing the substance to be oxidized to the anode section, A step of acquiring characteristic data of the power supplied to the electrolytic cell, characteristic data of the gas input to the electrolytic cell, electrical characteristic data of the electrolytic cell, characteristic data of the output gas of the electrolytic cell, and temperature data of the electrolytic cell during the operation of the electrolytic cell, A step of processing the power characteristic data, the gas characteristic data, the electrical characteristic data, the output gas characteristic data, and the temperature data, and determining the state of the electrolytic cell using the equivalent circuit model and equivalent circuit parameters of the electrolytic cell. An electrolytic method comprising the following. (Technical proposal 11) The electrolysis method according to Technical Proposal 10, wherein the deterioration state of the electrolytic cell is determined by the equivalent circuit model and the equivalent circuit parameters. (Technical proposal 12) An electrolysis method according to Technical Proposal 10 or Technical Proposal 11, comprising using the acquired data and the simulation data of the equivalent circuit model to calculate the equivalent circuit parameters by fitting, and detecting the deterioration of the electrolytic cell based on the information of the equivalent circuit parameters. (Technical proposal 13) An electrolytic apparatus according to any one of Technical Proposals 10 to 12, which estimates the location of deterioration by comparing the equivalent circuit parameters before actual operation or during design with the equivalent circuit parameters during actual operation. (Technical proposal 14) An electrolysis method according to any one of Technical Proposals 11 to 13, wherein the degree of degradation expressed as [(equivalent circuit parameter during actual operation) - (equivalent circuit parameter before actual operation or at the time of design)] / (equivalent circuit parameter before actual operation or at the time of design) is determined in the equivalent circuit parameter, and a judgment criterion is set for the degree of degradation to determine whether to stop the operation of the electrolytic cell. (Technical proposal 15) The electrolysis method according to technical proposal 10, wherein the step of acquiring the data of the electrolytic cell is a step of acquiring the data as a reference electrolytic cell, and the electrolytic cell is designed based on the equivalent circuit model and equivalent circuit parameters of the reference electrolytic cell. (Technical proposal 16) The step of selecting a candidate equivalent circuit model, A step of calculating the equivalent circuit parameters by fitting so that the squared error between the data of the reference electrolytic cell and the simulation data of the selected equivalent circuit model is reduced, A step of determining the validity of the equivalent circuit parameters using the squared error between the data of the reference electrolytic cell and the simulation data of the equivalent circuit model, The electrolysis method according to technical proposal 15, wherein the electrolytic cell is designed using the equivalent circuit model and equivalent circuit parameters that have been determined to be appropriate. [Explanation of Symbols]

[0102] 1... Electrolytic device, 2, 2A, 2B... Electrolytic cell, 3... Power supply control unit, 4... Power supply characteristic acquisition unit, 5... Gas / electrolyte control unit, 6... Input gas characteristic acquisition unit, 7... Electrical characteristic acquisition unit, 8... Output gas characteristic acquisition unit, 9... Temperature control unit, 10... Temperature acquisition unit, 11... Data storage unit, 12... Data processing unit, 21... First electrolyte, 22... First containment unit, 23... Reduction electrode (cathode), 24... Cathode unit, 25... Second electrolyte, 26... Second containment unit, 27... Oxidation electrode (anode), 28... Anode unit, 29... Diaphragm, 36... First flow path, 37... Second flow path.

Claims

1. An electrolytic cell comprising a cathode section to which a gas or liquid containing carbon dioxide as the substance to be reduced is supplied and a reducing electrode is positioned, an anode section to which a liquid containing an oxide is supplied and an oxidizing electrode is positioned, and a diaphragm provided between the cathode section and the anode section, A power supply characteristic acquisition unit that acquires the characteristics of the power supplied to the electrolytic cell, An input gas characteristic acquisition unit that acquires the characteristics of the gas input to the electrolytic cell, An electrical characteristics acquisition unit for acquiring the electrical characteristics of the electrolytic cell, An output gas characteristic acquisition unit that acquires the characteristics of the output gas of the electrolytic cell, including the characteristics of the output gas of the anode section, A temperature control unit for controlling the temperature of the electrolytic cell, A temperature acquisition unit that acquires the temperature of the electrolytic cell, A data storage unit that stores data from the power supply characteristics acquisition unit, the input gas characteristics acquisition unit, the electrical characteristics acquisition unit, the output gas characteristics acquisition unit, and the temperature acquisition unit, The data is sent from the data storage unit, and a data processing unit processes the data to determine the state of the electrolytic cell. It is equipped with, The data processing unit is configured to calculate equivalent circuit parameters by fitting using the measured data from the power supply characteristic acquisition unit, the input gas characteristic acquisition unit, the electrical characteristic acquisition unit, the output gas characteristic acquisition unit, and the temperature acquisition unit, as well as the simulation data of the equivalent circuit model of the electrolytic cell, and to perform degradation detection based on the information of the equivalent circuit parameters. The data processing unit is configured to calculate an equivalent circuit model in which a carbon dioxide reduction substance generation unit and a hydrogen generation unit are connected in parallel, and further comprises a cathode unit with a series resistor connected in series, a diaphragm unit, and an anode unit with an oxygen generation unit and a series resistor connected in series, and the cathode unit, the diaphragm unit and the anode unit are connected in series. The data processing unit is configured to calculate the current density of the carbon dioxide reduction substance generation section of the equivalent circuit model based on a relational expression that includes the current density expressed by the Tafel equation and the limiting current density for the generation of carbon dioxide reduction substances as variables. The electrolytic apparatus is configured such that the data processing unit calculates the current density limiting the production of the carbon dioxide reducing substance based on a relational expression that includes the flow rate of the substance to be reduced introduced into the cathode and the flow rate of the substance to be reduced moving from the cathode to the anode as variables.

2. The electrolytic apparatus according to claim 1, further comprising a display unit that displays information including the equivalent circuit model, the equivalent circuit parameters, and the determined state.

3. The electrolytic apparatus according to claim 1, wherein the data processing unit is configured to estimate the location of deterioration by comparing the equivalent circuit parameters before actual operation or during design with the equivalent circuit parameters during actual operation.

4. The electrolytic apparatus according to claim 3, wherein the data processing unit is configured to determine the degree of deterioration of the equivalent circuit parameter, which is expressed as [(equivalent circuit parameter during actual operation) - (equivalent circuit parameter before actual operation or at the time of design)] / (equivalent circuit parameter before actual operation or at the time of design), and to determine whether to stop the operation of the electrolytic cell by setting a judgment criterion for the degree of deterioration.

5. The electrolytic apparatus according to claim 1, wherein the data processing unit is installed in the cloud and configured to remotely determine the state of the electrolytic cell.

6. The electrolytic apparatus according to any one of claims 1 to 5, wherein the electrolytic cell is configured to produce a carbon compound when carbon dioxide is supplied as the material to be reduced.

7. A step of operating an electrolytic cell comprising a cathode section where a reducing electrode is located, an anode section where an oxidizing electrode is located, and a diaphragm provided between the cathode section and the anode section, wherein a gas or liquid containing carbon dioxide as the substance to be reduced is supplied to the cathode section, and a liquid containing the substance to be oxidized is supplied to the anode section, A step of acquiring characteristic data of the power supplied to the electrolytic cell, characteristic data of the gas input to the electrolytic cell, electrical characteristic data of the electrolytic cell, characteristic data of the output gas of the electrolytic cell including the characteristics of the output gas of the anode, and temperature data of the electrolytic cell during the operation of the electrolytic cell. A step of processing the power characteristic data, the gas characteristic data, the electrical characteristic data, the output gas characteristic data, and the temperature data, and determining the state of the electrolytic cell using the equivalent circuit model and equivalent circuit parameters of the electrolytic cell. It is equipped with, Using the acquired data and the simulation data of the equivalent circuit model, the equivalent circuit parameters are calculated by fitting, and the degradation of the electrolytic cell is detected based on the information of the equivalent circuit parameters. As the equivalent circuit model, the carbon dioxide reduction substance generation unit and the hydrogen generation unit are connected in parallel, and the circuit further comprises a cathode unit with a series resistor connected in series, a diaphragm unit, and an anode unit with an oxygen generation unit and a series resistor connected in series, and the cathode unit, the diaphragm unit and the anode unit are connected in series, and an equivalent circuit is calculated in which the cathode unit, the diaphragm unit and the anode unit are connected in series. The current density of the carbon dioxide reduction substance generation section of the equivalent circuit model is calculated based on a relational expression that includes the current density expressed by the Tafel equation and the current density at which carbon dioxide reduction substances are generated as variables. An electrolysis method for calculating the current density limiting the production of the carbon dioxide reducing substance based on a relational expression that includes the flow rate of the substance to be reduced introduced into the cathode and the flow rate of the substance to be reduced moving from the cathode to the anode as variables.

8. The electrolysis method according to claim 7, further comprising the step of displaying information including the equivalent circuit model, the equivalent circuit parameters, and the determined state on a display unit.

9. The electrolysis method according to claim 7, wherein the location of deterioration is estimated by comparing the equivalent circuit parameters before actual operation or during design with the equivalent circuit parameters during actual operation.

10. The electrolysis method according to claim 7, wherein the degree of degradation expressed as [(equivalent circuit parameter during actual operation) - (equivalent circuit parameter before actual operation or at the time of design)] / (equivalent circuit parameter before actual operation or at the time of design) is determined in the equivalent circuit parameter, and a judgment criterion is set for the degree of degradation to determine whether to stop the operation of the electrolytic cell.

11. The electrolysis method according to claim 7, wherein the step of acquiring the data of the electrolytic cell is a step of acquiring the data as a reference electrolytic cell, and the electrolytic cell is designed based on the equivalent circuit model and equivalent circuit parameters of the reference electrolytic cell.

12. The step of selecting a candidate equivalent circuit model, A step of calculating the equivalent circuit parameters by fitting so that the squared error between the data of the reference electrolytic cell and the simulation data of the selected equivalent circuit model is reduced, A step of determining the validity of the equivalent circuit parameters using the data of the reference electrolytic cell and the squared error of the simulation data of the equivalent circuit model, The electrolysis method according to claim 11, wherein the electrolytic cell is designed using the equivalent circuit model and equivalent circuit parameters that have been determined to be appropriate.

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