Electrolytic device simulator, simulation method, and electrolytic device

Abstract

To provide an electrolytic device simulator capable of determining a state close to a real operation of an electrolytic cell or an electrolytic cell stack.SOLUTION: A simulator 100 according to an embodiment of the present invention is an electrolytic device simulator that simulates the performance of a first cell stack comprising one or a plurality of electrolytic cells each comprising a cathode carrying out a reductive reaction and an anode carrying out an oxidation reaction by calculation, and comprises a calculation unit 120 performing calculation using a first group of variables representing at least one of the flooding and salt precipitation in the first electrolytic cell stack, in a calculation method implemented in the simulator 100.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] Embodiments of the present invention relate to a simulator for an electrolytic apparatus, a simulation method, and an electrolytic apparatus. [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 with fluctuating output, making it difficult to ensure a stable power supply. Therefore, attempts are being made to stabilize the power supply by storing electricity generated from renewable energy sources in batteries. However, storing electricity presents challenges such as the cost of batteries and losses during storage.

[0003] In response to these issues, technologies that convert electrical energy into chemical substances (chemical energy) are attracting attention. These technologies include using electricity generated from renewable energy sources to electrolyze water and produce hydrogen from water, electrochemically reducing carbon dioxide to produce carbon monoxide, formic acid, methanol, methane, acetic acid, ethanol, ethane, ethylene, and other carbon compounds, or electrochemically reducing nitrogen to produce ammonia. Storing these chemical substances in cylinders or tanks has the advantage of reducing energy storage costs and minimizing storage losses compared to storing electricity (electrical energy) in batteries.

[0004] Electrolysis of water (H2O), carbon dioxide (CO2), nitrogen (N2), etc., as described above, is often carried out using electrolytic cells or electrolytic cell stacks that stack multiple such cells. Electrolytic cell stacks present challenges such as flooding and salt deposition, which lead to performance degradation. For example, in a CO2 electrolytic cell where electrolyte is supplied to the anode and carbon dioxide to the cathode, the electrolyte may migrate from the anode to the cathode. This migrated electrolyte inhibits carbon dioxide from reaching the reaction field on the catalyst surface of the cathode, causing a decrease in the performance of the electrolytic cell. Therefore, there is a need for technologies to predict the performance of cell stacks while considering such flooding and salt deposition, and technologies to control the cell stacks to suppress flooding and salt deposition. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2021-046574 [Patent Document 2] Japanese Patent Publication No. 2020-045515 [Non-patent literature]

[0006] [Non-Patent Document 1] R.Guan and A.Bazylak, Electrochimica Acta, 447, 42103 (2023) [Non-Patent Document 2] DGWheeler et al., Energy & Environmental Science, 13, 5126-5134 (2020) [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The problem to be solved by the present invention is to provide a simulator for an electrolysis device, a simulation method, and an electrolysis device including such a simulator, which enable determination of a state close to actual operation of an electrolysis cell or an electrolysis cell stack.

Means for Solving the Problem

[0008] The simulator of the embodiment is a simulator of an electrolysis device that calculates and simulates the performance of a first cell stack including one or more electrolysis cells each having a cathode that performs a reduction reaction and an anode that performs an oxidation reaction, and in the calculation method implemented in the simulator, it includes an arithmetic unit that performs an operation using a first variable group representing at least one of flooding and salt precipitation in the first electrolysis cell stack.

Brief Description of the Drawings

[0009] [Figure 1] It is a diagram showing a first example of the simulator of the embodiment. [Figure 2] It is a diagram showing an example of an electrolysis device whose performance is simulated by calculation using the simulator of the embodiment. [Figure 3] It is a diagram showing a second example of the simulator of the embodiment. [Figure 4] It is a diagram showing a third example of the simulator of the embodiment. [Figure 5] It is a diagram showing a fourth example of the simulator of the embodiment. [Figure 6] It is a diagram showing a fifth example of the simulator of the embodiment. [Figure 7] It is a diagram schematically showing the temporal change of the light intensity in the cathode flow path as one of the first variable groups of the simulator of the embodiment. [Figure 8] It is a diagram showing an analysis example of the result of performing X-ray imaging on the cross section of the electrolysis cell as one of the first variable groups of the simulator of the embodiment. [Figure 9]This figure shows an example of the analysis results obtained by performing X-ray imaging of the cathode cross-section while changing the current density applied to the electrolytic cell, which is one of the first variables in the simulator of the embodiment. [Figure 10] This figure shows an example of an electrolytic apparatus according to the embodiment. [Figure 11] This figure shows another example of the electrolytic apparatus of the embodiment. [Figure 12] This is a conceptual diagram of the simulator for the embodiment. [Figure 13] This is a first flow diagram of the control method for an electrolytic device according to an embodiment. [Figure 14] This is a second flow diagram of the control method for the electrolytic device according to the embodiment. [Modes for carrying out the invention]

[0010] The following description will refer to the drawings to explain the simulator of the electrolytic apparatus according to the embodiment, the simulation method, and the electrolytic apparatus equipped with such a simulator. 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] The electrolytic apparatus to be simulated by the simulator of the embodiment comprises a first cell stack having one or more electrolytic cells, each having a cathode for a reduction reaction and an anode for an oxidation reaction. The size of the first cell stack to be simulated and the number of stacked electrolytic cells are not limited. Typically, the electrode area is several cm². 2 From several thousand centimeters 2 The number of layers typically ranges from 1 (single cell) to several hundred.

[0012] Figure 1 shows a first example of the simulator 100 of the embodiment. As shown in Figure 1, the simulator 100 of the embodiment is a computer that implements a simulation model (calculation method). The model comprises an input unit 110, a calculation unit 120, and an output unit 130. The input unit 110 receives variables that reflect the operating state of the first cell stack (first input variables), such as temperature, pressure, and current density, and parameters that do not depend on the operating state, such as the thickness of the material, porosity, and coefficients that represent the properties of the catalyst material. Calculations are performed based on these inputs.

[0013] The calculations may use analytical equations, numerical methods, or machine learning. They may also be multiphysics models that couple mass balance, energy balance, chemical reaction rates, overpotential calculations, etc. These calculations may involve convergence calculations. The output obtained as a result of the calculations represents the performance of the first cell stack. Examples include, but are not limited to, current-voltage characteristics, product selectivity, and Faraday efficiency.

[0014] The simulator 100 of the embodiment is characterized by utilizing a first variable group that represents at least one of flooding and salt deposition in the first electrolytic cell stack. The first variable group consists of one or more variables. The variables of the first variable group may be inputs to the calculation, may be calculated indirectly from other variables in the calculation, or may be both. The input unit 110 of the simulator 100 shown in Figure 1 receives a first input variable that reflects the operating state of the first electrolytic cell stack and parameters that do not depend on the operating state, as well as a second input variable consisting of all or some of the variables that make up the first variable group.

[0015] The variables in the first group of variables can be selected from the composition, mass, volume, density, temporal and spatial changes of the solution or solid in a specific region of the first electrolytic cell stack, such as the anode channel, anode, diaphragm, cathode, or cathode channel, or from dimensionless values ​​of the above quantities. Furthermore, in a stack comprising multiple electrolytic cells, statistical quantities of the above quantities in each cell within the stack (e.g., mean, standard deviation, etc.) can also be adopted as variables in the first group of variables. Examples of temporal and spatial changes include the accumulation and disappearance of solution or solid in a region inside the cell of interest, and the flux entering and leaving the above regions. Examples of dimensionless values ​​include the proportion of liquid in the cathode channel volume, and the inflow flux of the solution at a certain position in the cathode normalized to the value at the start of electrolysis.

[0016] Figure 2 shows a carbon dioxide (CO2) electrolytic cell stack 10 as an example of an electrolytic apparatus whose performance is simulated by calculation using the simulator 100 of the embodiment. The electrolytic cell stack 10 shown in Figure 2 comprises electrolytic cells 20. Although only one electrolytic cell (single cell) 20 is shown in Figure 2, several hundred single cells 20 can be stacked to form an electrolytic cell stack 10. Here, the term electrolytic cell stack 10 includes both a single electrolytic cell 10 and a stack of the required number of such cells. The electrolytic cell 20 comprises a cathode section 30, an anode section 40, and a separator (diaphragm) 50.

[0017] The cathode section 30 comprises a reducing electrode (cathode) 31 having a metal catalyst layer, a cathode channel 32, and a cathode current collector plate 33. The cathode channel 32 is a gas channel that supplies CO2 gas to the cathode 31 as the gas to be reduced. The cathode 31 is positioned in contact with the CO2 flowing through the cathode channel 32. The anode section 40 comprises an anode (oxidizing electrode) 41, an anode channel 42, and an anode current collector plate 43. The anode channel 42 is an electrolyte channel that supplies an electrolyte as an anode solution to the anode 41. The electrolyte contains water (H2O) or hydroxide ions (OH) as the oxide to be reduced. -It contains ). The anode 41 is positioned so as to be in contact with the anode solution flowing through the anode channel 42.

[0018] The electrolytic cell stack 10 comprises a gas supply unit 60 that supplies CO2 to the electrolytic cell 20 and an anode solution supply unit (supply system) 70 that supplies anode solution to the electrolytic cell 20. The gas supply unit 60 comprises a CO2 containment unit 61 such as a CO2 gas cylinder and a CO2 adjustment unit 62 that adjusts the flow rate of CO2 gas, and supplies CO2 gas from the CO2 containment unit 61 to the cathode channel 32 via gas piping 63. Ions are supplied to the cathode 31 of the electrolytic cell 20 shown in Figure 2 via a separator 50, and CO2 gas is supplied from the cathode channel 32. The CO2 reduction products are mainly discharged from the cathode channel 32. The anode solution supply unit 70 comprises an anode solution tank 71 and a pump 72, and supplies anode solution from the anode solution tank 71 to the anode channel 42 via the pump 72 and electrolyte piping 73. The anode solution circulates through the anode channel 42 and the electrolyte piping 73.

[0019] The electrolytic cell 20 is generally sandwiched between a pair of support plates (not shown) and further fastened with bolts or the like. The cathode current collector plate 33 and the anode current collector plate 43 are connected to the power supply 80. The power supply 80 is not limited to ordinary commercial power or batteries, but may also be a power supply that converts renewable energy into electrical energy. Examples of such power supplies include power supplies that convert kinetic 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 such as devices that convert vibrational energy such as sound into electrical energy.

[0020] The cathode 31 is an electrode (reduction electrode) that causes a reduction reaction of carbon dioxide (CO2) as the gas to be reduced, producing carbon compounds such as carbon monoxide (CO), methane (CH4), ethane (C2H6), ethylene (C2H4), methanol (CH3OH), ethanol (C2H5OH), and ethylene glycol (C2H6O2). In the cathode 31, a side reaction may occur simultaneously with the reduction reaction of carbon dioxide (CO2), generating hydrogen (H2) through the reduction reaction of water (H2O). In such a cathode section 30, CO2 gas is introduced from the gas supply section 60 through the gas inlet of the cathode flow path 32. Furthermore, reaction product gases containing CO, H2, etc. are discharged through the gas outlet, and the discharged gas is sent to a valuable materials manufacturing section (not shown) or recovered in a product recovery section.

[0021] The cathode 31 has a porous structure that allows gas or liquid to move between the separator 50 and the cathode channel 32, such as a mesh material, a punching material, a porous body, or a metal fiber sintered body. The cathode 31 comprises, for example, a porous substrate containing carbon fibers and a cathode catalyst layer provided on the porous substrate. A porous layer denser than the porous substrate may be placed between the porous substrate and the cathode catalyst layer. The porous substrate is located on the cathode channel 32 side, and the cathode catalyst layer is located on the separator 50 side. The cathode catalyst layer may be embedded within the porous substrate. The cathode catalyst layer of the cathode 31 preferably has catalyst nanoparticles or catalyst nanostructures. The cathode catalyst layer is preferably composed of a catalyst material (cathode catalyst material) that can reduce CO2 to produce carbon compounds and reduce the overpotential of such reactions.

[0022] Anode 41 undergoes an oxidation reaction of water (H2O) in the anode solution, producing oxygen (O2) and hydrogen ions (H2O). + ) generates hydroxide ions (OH) generated in the cathode section 30. -) is an electrode (oxidation electrode) that causes an oxidation reaction and generates oxygen and water. In the anode part 40, the anode solution is introduced and discharged by the pump 72 through the solution inlet and solution outlet of the anode flow path 42. The anode solution flows through the anode flow path 42 so as to contact the anode 41. When an aqueous solution of an electrolyte is used as the anode solution, the anode 41 can oxidize water (H2O) to generate oxygen and hydrogen ions, or oxidize hydroxide ions (OH - ) to generate water and oxygen, and is preferably mainly composed of a catalyst material (anode catalyst material) capable of reducing the overvoltage of such a reaction.

[0023] The anode 41 includes a base material (porous base material) having a porous structure such as a mesh material, a punching material, or a porous sintered body, which can move the anode solution and ions between the separator 50 and the anode flow path 42. As the anode solution, an aqueous solution containing an arbitrary electrolyte can be used. Examples of such electrolytic solutions include phosphate ions (PO4 2- ), borate ions (BO3 3- ), sodium ions (Na + ), potassium ions (K + ), calcium ions (Ca 2+ ), lithium ions (Li + ), cesium ions (Cs + ), magnesium ions (Mg 2+ ), chloride ions (Cl - ), hydrogen carbonate ions (HCO3 - ), carbonate ions (CO3 2- ) and the like. The separator 50 is made of a material that can move ions between the anode 41 and the cathode 31 and can separate the anode part 40 and the cathode part 30.

[0024] In the electrolytic cell stack 10 described above, electrolyte may move from the anode 41 side to the cathode 31 side. The electrolyte that moves to the cathode 31 side inhibits carbon dioxide from reaching the reaction field on the catalyst surface of the cathode 31, causing a decrease in the performance of the electrolytic cell. Therefore, it is necessary to predict the performance of the electrolytic cell stack 10 while considering such flooding and salt deposition phenomena, and to suppress flooding and salt deposition. Accordingly, in the simulator 100 of the embodiment, by using a variable representing at least one of flooding and salt deposition as the first variable group and simulating the performance by calculation, the performance of the electrolytic cell stack 10 can be simulated under conditions close to actual usage conditions.

[0025] The variables in the first group of variables can be selected from the composition, mass, volume, density, temporal and spatial changes of the solution or solid in a specific region within the electrolytic cell stack 10, such as the anode channel 42, anode 41, separator 50, cathode 31, and cathode channel 32, or dimensionless values ​​of each of the above quantities. Furthermore, in a cell stack comprising multiple electrolytic cells 20, statistical quantities (e.g., mean, standard deviation, etc.) of the above quantities in each cell within the stack can also be adopted as variables in the first group of variables. Examples of temporal and spatial changes include the accumulation and disappearance of solution or solid in a region within the electrolytic cell of interest, and the flux entering and leaving each of the above regions. Examples of dimensionless values ​​include the proportion of liquid in the volume of the cathode channel 32, and the inflow flux of the solution at a certain position in the cathode 31 normalized to the value at the start of electrolysis.

[0026] Figure 3 shows a second example of the simulator 100 of the embodiment. In the simulator 100 of the embodiment, the variables constituting the first group of variables may be defined as functions of other variables or parameters. For example, the volume of solution in the cathode channel can be defined as a function of the operating temperature, the dew point of the gas supplied to the electrolytic cell, the wettability of the channel member, etc.

[0027] Figure 4 shows a third example of the simulator 100 of the embodiment. In the simulator 100 of the embodiment, other variables and model parameters may be updated based on the variables that constitute the first group of variables. For example, the porosity of the cathode, the exchange current density, the local temperature of the reaction field, etc., can be updated based on the volume of the solution in the cathode. Figure 4 shows a case in which other variables and model parameters are updated from the input to the calculation (second input variables) from the first group of variables, but other variables and model parameters may also be updated from the variables calculated within the model from the first group of variables.

[0028] Figure 5 shows a fourth example of the simulator 100 of the embodiment. In the simulator 100 of the embodiment, the values ​​of the first group of variables calculated from the variables and parameters may be used to update other variables and parameters. In this case, the variables and parameters updated based on the values ​​of the first group of variables may be the same ones used to determine the values ​​of the first group of variables, or they may not be.

[0029] Figure 6 shows a fifth example of the simulator 100 of the embodiment. The first group of variables are the composition, mass, volume, density, or temporal and / or spatial changes of the solution or solid inside the electrolytic cell. All or some of these values ​​can be determined from the analysis of the first electrolytic cell stack or the second electrolytic cell stack having equivalent properties to the first electrolytic cell stack. The variables of the first group of variables dealt with in the simulator 100 shown in Figure 6, or the method for calculating the variables, are defined based on the results of analyzing the first electrolytic cell stack 10 or the second electrolytic cell stack with the analyzer 210.

[0030] The analyzer 210 is configured to analyze the electrolytic cell stack 10 using at least one of electromagnetic waves, particle beams, sound waves, electromagnetic fields, electric currents, and voltages, and obtains quantitative information about the solution or solid by analyzing the results. In this case, signals other than electromagnetic waves, particle beams, sound waves, electromagnetic fields, electric currents, and voltages may also be used. Specific analytical methods include imaging of the inside of the electrolytic cell using X-rays, visible light, neutron beams, ultrasound, nuclear magnetic resonance, etc., and measurement of electrochemical impedance using alternating current and voltage. Multiple analytical methods may be combined.

[0031] If it is difficult to directly apply the analytical method to the first electrolytic cell stack, a second electrolytic cell stack with equivalent characteristics can be prepared, and the analysis results can be used to construct a simulator of the first electrolytic cell stack. For example, if the surface of the first electrolytic cell stack is made of metal, it is difficult to analyze the inside of the cell using visible light. In this case, a second electrolytic cell stack can be fabricated by replacing the metal surface component with a transparent material, and the analysis results can be used to simulate the first electrolytic cell stack. Similarly, if the first electrolytic cell stack is made of a material that strongly absorbs X-rays, it is difficult to image the inside of the cell using transmitted X-rays. In such cases, the second electrolytic cell stack can be fabricated by reducing the thickness of the component made of the material that strongly absorbs X-rays, or by changing it to a material that absorbs less X-rays. It is also possible to fabricate a second electrolytic cell stack that is easier to handle by reducing the number of layers of the first electrolytic cell stack or by reducing the electrode area.

[0032] The variables in the first group of variables may be inputs to the calculation, or they may be calculated indirectly within the model from other variables. Therefore, there are two possible ways to utilize the analysis results of the first or second electrolytic cell stack. One is to obtain and use the values ​​of the variables that represent at least one degree of flooding and salt precipitation. The other is to obtain and use the relationship between equipment conditions such as operating conditions and material properties and the values ​​in the first group of variables. The former can be applied when the values ​​of the first group of variables are determined by directly analyzing the first electrolytic cell stack during operation, and calculations are performed based on these values ​​to predict the future performance of the first electrolytic cell stack. For example, observation using visible light or ultrasound, or measurement of electrochemical impedance using alternating current and / or voltage, do not require large-scale equipment, so the equipment for analysis can be installed alongside the electrolytic cell stack, and the analysis can be performed directly during the operation of the electrolytic cell stack.

[0033] The latter method can be used even when the first electrolytic cell stack is not directly analyzed during operation. The first or second electrolytic cell stack is analyzed in advance under various conditions to understand how the values ​​of the first set of variables change depending on the conditions, and this relationship is incorporated into the model. This allows for the prediction of performance during operation without performing special analysis, by estimating the state of flooding and / or salt deposition solely from conventionally measured operating conditions such as temperature, pressure, and current density, thereby predicting performance that takes flooding and / or salt deposition into account. For example, analysis using X-rays or neutron beams, or measurements using nuclear magnetic resonance, require large-scale and advanced equipment. Typically, electrolytic devices are used in environments without such specialized analytical equipment. Therefore, when using these analyses, the first or second electrolytic cell stack is analyzed in advance using specialized equipment or facilities, and the results are incorporated into the model, allowing the simulation of the embodiment to be used at the electrolytic device's actual usage site. The two methods described above can also be used in combination. That is, both variables obtained from real-time analysis and variables calculated within the model can be used.

[0034] For imaging experiments measuring transmitted X-ray light, analysis based on the Lambert-Beer law is useful. The Lambert-Beer law is written as follows: A = -log 10 (I out / I in )=ECL …(1) In equation (1), A is absorbance, I in and I out ∫ is the light intensity of the incident and transmitted light, E is the molar absorption count, C is the molar concentration of the medium, and L is the length of the medium. Using this, it is possible to quantify a substance within the measurement range. For example, the cathode channel of a carbon dioxide electrolytic cell is filled with carbon dioxide gas at the start of electrolysis, and X-ray imaging can be used to quantify the amount of liquid flowing into it.

[0035] In an experiment in which X-rays are irradiated from the cross-sectional direction of an electrolytic cell to a predetermined position in the cathode channel and the transmitted light intensity is observed, the transmitted light intensity before the start of electrolysis (time t=0) is I0, and the transmitted light intensity at a certain time t1 during electrolysis is I t1 Let's assume that at time t=0, only gas is present in the channel, but at t=t1, liquid has moved into the channel and absorbs the X-rays. Assuming that there is no precipitation of solid salts and that X-ray absorption by the gas and changes in the concentration of the liquid can be ignored, the difference in absorbance at the two times depends only on the amount of liquid in the channel, and the following equation (2) holds. - 10 (I t1 / I0)=E liq C liq L liq,t1 …(2) In equation (2), E liq and C liq The molar absorbance and molar concentration of the liquid are L liq,t1 is the length of the liquid occupying the depth direction at the observation position of the flow channel cross-section at time t1. From this, the measured I0 and I t1 From L liq,t1 We can obtain this and use it as a constituent variable of the first group of variables. Also, L liq,t1By integrating (or performing an approximate sum-of-products calculation) over the cross-section of the flow channel, the volume of liquid occupying the flow channel space can be obtained, and this can be used as a constituent variable of the first group of variables.

[0036] In addition to comparing time t1 before electrolysis begins and during electrolysis, it is also possible to compare two time points t1 and t2 during electrolysis. In that case, the transmitted light intensity I at both time points t1 and I t2 Therefore, the change in liquid volume between the two time points can be calculated using the following equation (3). - 10 (I t1 / I t2 )=E liq C liq (L liq,t2 -L liq,t1 ) …(32) It is also possible to obtain the rate of change in liquid volume by dividing the change in liquid volume by time. These can be used as constituent variables of the first group of variables. Figure 7 schematically shows the time change of light intensity in the cathode channel.

[0037] Figure 8 shows an example of analysis of X-ray imaging results for a cross-section of an electrolytic cell, including the cathode, diaphragm, and anode. Figure 8 shows the time evolution of the liquid volume at each location, calculated based on the X-ray transmitted light intensity measurement results. If the liquid volume within the first electrolytic cell stack is defined as the first variable group, the spatial and temporal changes of this variable can be understood based on such data.

[0038] Figure 9 shows an example of analysis of the results of X-ray imaging of the cathode cross-section while varying the current density applied to the electrolytic cell. Figure 9 calculates the amount of liquid present in the area of ​​interest of the cathode based on the X-ray transmitted light intensity measurement results, and defines the proportion of liquid in the volume of that area as the degree of saturation. Based on this data, the dependence of the first group of variables on current density and on current application time can be understood.

[0039] Many simulations that simulate the performance of conventional electrolytic cell stacks are known to determine steady-state performance based on the assumption of stable operation. In such simulations, it is not necessary to treat time as a variable in the calculation. In contrast, simulations that take degradation into account are expected to be able to predict the future performance of the electrolytic cell stack. Therefore, the simulation model of the embodiment may consider time as a variable for input, calculation, and output. In particular, the first group of variables representing at least one of flooding and salt precipitation may be time-dependent.

[0040] For example, during operation at a constant current density, flooding occurs, and the proportion of the liquid phase in the cathode catalyst layer increases over time. To simulate this, one method is to define the liquid volume and its rate of increase at each time point in a first variable group. As the values ​​of these first variables change, the performance values ​​obtained as a result of the calculation, such as voltage and product selectivity, also change over time. This makes it possible to predict performance beyond the time of interest. It is also possible to create a statistical model that predicts performance at a later time based on information about the operating conditions and cell performance from the start of operation of the electrolytic cell stack up to a certain time. According to the embodiment, a first variable group representing at least one of flooding and salt deposition can be incorporated into such a model. For example, when constructing a machine learning model that takes information about a certain period of time in the past, including the time of interest, as input and outputs the electrolytic cell performance for a certain period of time beyond that time, the prediction accuracy can be improved by including the first variable group in the input.

[0041] An electrolytic apparatus can be realized that includes the simulator and the first electrolytic cell stack described in each of the above examples. Here, the electrolytic apparatus may include components other than the simulator and the first electrolytic cell stack. For example, it may include an analytical device for analyzing the first electrolytic cell stack and a computer for analyzing the results of the analysis. Figure 10 shows an example of an electrolytic apparatus according to the embodiment. The electrolytic apparatus 200 shown in Figure 10 comprises a first electrolytic cell stack 10, an analytical device 210 for analyzing the first electrolytic cell stack, and a computer 211 for analyzing the results of the analytical device 210.

[0042] Observation using visible light or ultrasound, and measurement of electrochemical impedance using alternating current and / or voltage, can be performed relatively easily. Therefore, the analytical equipment (analytical device 210 and computer 211) can be installed alongside the first electrolytic cell stack 10, and analysis can be performed directly during the operation of the first electrolytic cell stack 10. On the other hand, when using X-ray imaging, neutron imaging, nuclear magnetic resonance imaging, etc., which require large-scale equipment, it is desirable to perform analysis in advance under various operating and material conditions, understand the correspondence between these conditions and the values ​​of the first group of variables, and incorporate this into the simulator's calculation method.

[0043] The electrolytic apparatus of this embodiment is equipped with detectors on the first electrolytic cell stack and the auxiliary equipment for driving it, and the data acquired using these detectors is input into a simulator, calculations are performed using this input, and the operation of the first electrolytic cell stack can be controlled using the results of these calculations. The auxiliary equipment includes, but is not limited to, power supplies, pumps, heaters, and piping. The detectors include, but are not limited to, thermometers, pressure gauges, dew point meters, ammeters, voltmeters, gas flow meters, and gas composition analyzers.

[0044] The operating conditions of the first electrolytic cell stack can be controlled using at least one value included in the calculations in the simulator. Here, the value included in the calculation refers to at least one selected from the input values ​​to the simulation model, the values ​​of variables defined in the calculations, and the values ​​obtained as output results. These values ​​may or may not be variables of the first group of variables. For example, the current pressure inside the first electrolytic cell stack input to the model, the assumed liquid volume inside the cell at present or in the future calculated based on operating conditions and material characteristics in the calculations, and the future product selectivity and cell voltage obtained as output of the calculations can be used, but are not limited to these.

[0045] In controlling the first electrolytic cell stack, the electrolytic device is equipped with a calculation unit and a control unit, and these are used. The calculation unit is a computer that receives at least one value included in the simulator's calculations and uses this to determine operating conditions that suppress degradation. The calculation unit may be a separate computer from the simulator in the embodiment described above, or it may be covered by implementing additional calculation functions in the simulator of the embodiment. The calculation method implemented in the calculation unit may use analytical equations, numerical solutions, or machine learning. Examples of operating condition determination by the calculation unit include raising the dew point of the supply gas to suppress salt deposition in response to a pressure increase inside the cell, and changing the inter-electrode differential pressure to suppress flooding in response to an increase in the assumed liquid volume inside the cell. The control unit is the part that sends signals to the first electrolytic cell stack and auxiliary equipment, etc., in order to realize the operating conditions obtained as a result of calculations by the calculation unit.

[0046] Figure 11 shows another example of the electrolytic apparatus of the embodiment. The electrolytic apparatus 200 shown in Figure 11 includes a calculation unit 91 and a control unit 92 in addition to the configuration of the electrolytic apparatus 200 shown in Figure 10. Furthermore, the first electrolytic cell stack 10 is equipped with auxiliary equipment such as a detector. In such an electrolytic apparatus 200, if an analysis device 210 for directly analyzing the first electrolytic cell stack 10 and a computer 211 for analyzing the analysis results are included, it is also possible to use the values ​​of the first group of variables acquired in real time during the operation of the first electrolytic cell stack 10 for decision-making in the calculation unit 91.

[0047] In the embodiment, a simulation model (computational method) that can be implemented in the simulator is also provided. The model consists of inputs, operations, and outputs. The operations may use analytical equations, numerical solutions, or machine learning. It may also be a multiphysics model that couples mass balance, energy balance, chemical reaction rates, overpotential calculations, etc. These operations may also involve convergence calculations.

[0048] The calculation method of the embodiment utilizes a first group of variables representing at least one of flooding and salt precipitation. As shown in Figure 12, the first group of variables consists of one or more variables. These variables of the first group of variables may be inputs to the calculation, or they may be calculated indirectly from other variables during the calculation. The variables of the first group of variables can be selected from the composition, mass, volume, density, temporal and / or spatial changes of the solution or solid in a specific region inside the first electrolytic cell stack, and dimensionless values ​​of each of the above quantities. Furthermore, in a stack comprising multiple electrolytic cells, the statistics of each of the above quantities in each electrolytic cell within the stack can also be adopted as variables of the first group of variables.

[0049] The embodiment also provides a control method for an electrolytic device. The control method follows, for example, the flow shown in Figures 13 and 14. If the electrolytic device does not include an analytical device, the control method follows, for example, the flow shown in Figure 13. If the electrolytic device includes an analytical device and a computer for analyzing the results, the control method follows, for example, the flow shown in Figure 14.

[0050] Simulations performed on large-scale computers can be replaced with approximate models, such as linear or nonlinear models. By simplifying the simulation in this way, it is expected that computational results comparable to those obtained on large-scale computers, but in a shorter time, can be obtained. Furthermore, by implementing the simplified model on edge devices such as microcontrollers, calculations simulating the simulation can be output on small devices. In addition, the simulation can be simplified by preparing the results of simulations for many parameter combinations and extracting the weights of a machine learning regression model that has learned from these results. For example, by mounting these weights on an edge device such as a microcontroller, calculations simulating the simulation can be output on small devices.

[0051] When the simplified model described above is used in calculations performed on a central processing unit (CSI) mounted on an edge device, which features low power consumption, low clock speed, and low number of computing elements, it is expected that comparable calculation results can be obtained for the same input in a shorter time than simulations performed on a large computer. By inputting the output of the electrolytic device's sensor array to such an edge device, calculation results can be performed with a shorter delay compared to large computers or simulations. This allows for the rapid transmission of control signals based on the input from the electrolytic device, resulting in a higher-performance electrolytic device.

[0052] In the embodiments described above, examples of applying the simulator of the embodiment to a CO2 electrolytic apparatus and such a CO2 electrolytic apparatus were mainly explained. However, the simulator of the embodiment may be applied to electrolytic apparatuses other than CO2 electrolytic apparatuses, and furthermore, such electrolytic apparatuses are also included. Examples of electrolytic apparatuses other than CO2 electrolytic apparatuses include, but are not limited to, H2O electrolytic apparatuses that electrolyze water (H2O) to produce hydrogen and oxygen, and N2 electrolytic apparatuses that electrolyze nitrogen (N2) to produce ammonia (NH3), etc.

[0053] The configurations of each embodiment can be applied in combination and partially substituted. While several embodiments of the present invention have been described here, 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, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as described in the claims. [Explanation of symbols]

[0054] 10...Electrolytic cell stack, 20...Electrolytic cell, 31...Cathode, 41...Anode, 50...Separator, 60...Gas supply unit, 70...Anode solution supply unit, 80...Power supply, 91...Calculation unit, 92...Control unit, 100...Simulator, 110...Input unit, 120...Calculation unit, 130...Output unit, 200...Electrolytic device, 210...Analyzer.

Claims

1. A simulator for an electrolytic device that simulates the performance of a first electrolytic cell stack by calculation, comprising one or more electrolytic cells, each comprising a cathode for performing a reduction reaction, an anode for performing an oxidation reaction, a cathode channel in contact with the cathode, an anode channel in contact with the anode, and a diaphragm provided between the cathode and the anode, The system comprises a calculation unit that performs calculations using a first group of variables representing at least one of flooding and salt deposition in the first electrolytic cell stack, The first group of variables includes at least one parameter selected from the group consisting of composition, mass, volume and density, temporal and spatial changes in the composition, mass, volume and density, and dimensionless values ​​thereof, for solutions and solids present in at least a portion of the region of the cathode, anode, cathode channel, anode channel, and diaphragm. Simulator.

2. The first group of variables includes variables that are expressed as functions of other variables or parameters in the calculation method described above. The simulator according to claim 1, wherein the calculation unit is configured to perform calculations using the first group of variables, including the aforementioned variables.

3. The simulator according to claim 1, wherein the calculation unit is configured to perform calculations using other variables and parameters that are updated according to the values ​​of the first group of variables.

4. The values ​​of the first group of variables are determined based on the results of analyzing the first electrolytic cell stack or a second electrolytic cell stack having characteristics equivalent to the first electrolytic cell stack using at least one of electromagnetic waves, particle beams, sound waves, electromagnetic fields, currents, and voltages. The simulator according to claim 1, wherein the calculation unit is configured to perform calculations using the first group of variables defined based on the results of the analysis.

5. The simulator according to claim 4, wherein the analysis is an imaging experiment to visualize the state inside the first or second electrolytic cell stack.

6. The values ​​of the first group of variables are determined by the results of the analysis of the imaging experiment based on the Lambert-Beer law. The simulator according to claim 5, wherein the calculation unit is configured to perform calculations using the first group of variables defined based on the results of the analysis.

7. The values ​​of the first group of variables are determined from the absorbance obtained in the above analysis. The simulator according to claim 6, wherein the calculation unit is configured to perform calculations using the first group of variables obtained from the absorbance.

8. The aforementioned first group of variables includes time-dependent variables, The simulator according to claim 1, wherein the calculation unit is configured to perform calculations using the first group of variables, which includes a time-dependent variable.

9. A simulation method for an electrolytic apparatus that calculates the performance of a first electrolytic cell stack comprising one or more electrolytic cells, each comprising a cathode for performing a reduction reaction, an anode for performing an oxidation reaction, a cathode channel in contact with the cathode, an anode channel in contact with the anode, and a diaphragm provided between the cathode and the anode, In the calculation method described above, a first set of variables representing at least one of flooding and salt deposition in the first electrolytic cell stack is used, The first group of variables includes at least one parameter selected from the group consisting of composition, mass, volume and density, temporal and spatial changes in the composition, mass, volume and density, and dimensionless values ​​thereof, for solutions and solids present in at least a portion of the region of the cathode, anode, cathode channel, anode channel, and diaphragm. Simulation method.

10. The simulation method according to claim 9, wherein the first group of variables includes variables that are expressed as functions of other variables or parameters in the calculation method.

11. The simulation method according to claim 9, wherein other variables and parameters are updated according to the values ​​of the first group of variables.

12. The simulation method according to claim 9, wherein the values ​​of the first group of variables are determined based on the results of analyzing the first electrolytic cell stack or a second electrolytic cell stack having characteristics equivalent to the first electrolytic cell stack using at least one of electromagnetic waves, particle beams, sound waves, electromagnetic fields, currents, and voltages.

13. The simulation method according to claim 12, wherein the analysis is an imaging experiment to visualize the state inside the first or second electrolytic cell stack.

14. The simulation method according to claim 13, wherein, in determining the values ​​of the first group of variables, the results of the imaging experiment are analyzed based on the Lambert-Beer law.

15. The simulation method according to claim 14, wherein the values ​​of the first group of variables are determined from the absorbance obtained in the analysis.

16. The simulation method according to claim 9, wherein the first group of variables includes time-dependent variables.

17. A simulator according to any one of claims 1 to 8, The first electrolytic cell stack and An electrolytic device equipped with the following:

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