Electrolysis system and electrolysis method

Abstract

This suppresses the current leaking from the electrolyte when the electrolysis cell stack is energized. [Solution] According to this embodiment, the electrolysis system comprises an electrolysis cell stack, a power supply unit, a gas supply unit, an electrolyte supply unit, a supply pipe, and a discharge pipe. The electrolysis cell stack electrolyzes the gas and the electrolyte. The power supply unit applies a voltage between the anode and cathode of the electrolysis cell stack. The gas supply unit supplies the electrolyte to the other electrode. The supply pipe supplies anode fluid and cathode fluid to the electrolysis cell stack. The discharge pipe discharges the anode fluid and cathode fluid from the electrolysis cell stack. At least one of the supply pipe and the discharge pipe has a plurality of insulating pipes whose interiors are made of electrical insulating material, and a good conductor pipe of good conductors connected between the plurality of insulating pipes, the good conductor pipe being electrically connected to a predetermined low potential body.

Description

[Technical Field]

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

[0002] An electrolysis system is a system that performs oxidation reactions at the anode and reduction reactions at the cathode in an electrolysis cell stack. When this electrolysis cell stack is energized, current leaks through the electrolyte to equipment far from the electrodes. Furthermore, if the wetted parts of the equipment are good conductors, this leakage current can cause the equipment to deteriorate, potentially reducing its long-term durability.

[0003] For this reason, to prevent electrical leakage, a double-walled tube is known, which consists of an inner tube through which the electrolyte flows and an outer tube located outside the inner tube with a space between them. The inner tube is separated by an insulating pipe made of insulating material to electrically insulate the electrolysis cell stack from the equipment. This ensures insulation between the separated inner tubes. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2024-51868 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, while such insulated piping ensures insulation between the inner tubes, there is a risk that current may leak to equipment far from the electrodes due to the electrolyte flowing through the inner tubes.

[0006] The problem that this invention aims to solve is to provide an electrolysis system and electrolysis method that can suppress the current leaking from the electrolyte when the electrolysis cell stack is energized. [Means for solving the problem]

[0007] The electrolysis system according to this embodiment comprises an electrolysis cell stack, a power supply unit, a gas supply unit, an electrolyte supply unit, a supply pipe, and a discharge pipe. The electrolysis cell stack performs electrolysis by flowing gas and electrolyte through either the anode or cathode electrode and applying a voltage. The power supply unit applies a voltage between the anode electrode and the cathode electrode of the electrolysis cell stack. The gas supply unit supplies electrolyte to the other electrode. The supply pipe supplies anode fluid and cathode fluid to the electrolysis cell stack. The discharge pipe discharges anode fluid and cathode fluid from the electrolysis cell stack. At least one of the supply pipe and the discharge pipe has a plurality of insulating pipes whose interiors are made of electrical insulating material and a good conductor pipe of good conductors connected between the plurality of insulating pipes, and the good conductor pipes are set to a predetermined reference potential. [Effects of the Invention]

[0008] This can suppress the current leaking from the electrolyte when the electrolysis cell stack is energized. [Brief explanation of the drawing]

[0009] [Figure 1] A schematic diagram showing the configuration of the first embodiment of the present invention. [Figure 2] A flowchart illustrating a control example. [Figure 3] A schematic diagram showing an example configuration of the second embodiment. [Figure 4] A schematic diagram showing an example configuration of the third embodiment. [Figure 5] A schematic diagram showing an example configuration of the fourth embodiment. [Figure 6] A schematic diagram showing an example configuration of the fifth embodiment. [Modes for carrying out the invention]

[0010] Hereinafter, embodiments will be described with reference to the drawings. The relationship between the thickness and the planar dimensions of each component shown in the drawings, the ratio of the thicknesses of each component, etc. may differ from the actual object. The vertical direction may differ from the vertical direction according to the gravitational acceleration. In the embodiments, substantially the same components are denoted by the same reference numerals and the description thereof will be omitted as appropriate. In this specification, "connection" includes not only physical connection but also electrical connection, and includes not only direct connection but also indirect connection unless otherwise specified.

[0011] (First Embodiment) [1-1 Configuration]

[0012] The configuration example of the first embodiment of the present invention will be described using the configuration diagram of FIG. 1. FIG. 1 is a schematic diagram showing a configuration example of an electrolysis system according to the first embodiment. The electrolysis system 1 of the present embodiment includes an electrolysis cell stack 2, a carbon dioxide-containing gas supply device 3, a carbon dioxide-containing gas supply pipe 5, an electrolytic solution supply device 6, an electrolytic solution supply pipe 8, a carbon dioxide-containing gas discharge pipe 9, an electrolytic solution discharge pipe 10, a pipe temperature regulator 11, a humidifier 12, a DC power supply device 13, and a control unit 20. Each arrow shown in FIG. 1 indicates the direction in which the corresponding fluid flows.

[0013] The electrolysis cell stack 2 is composed of a plurality of electrolysis cells each including a cathode 4, an anode 7, and a separator (not shown) that separates the cathode 4 and the anode 7. Although the electrolysis cell stack 2 according to the present embodiment is composed of a plurality of stacked layers, it is not limited thereto. For example, it may be composed of a single layer.

[0014] The cathode 4 has a cathode catalyst for reducing a reduction target such as carbon dioxide to produce a cathode product, and a cathode electrode to which a voltage is applied. Examples of the cathode product include those containing carbon compounds such as carbon monoxide.

[0015] The anode 7 has an anode catalyst for oxidizing an object to be oxidized such as water to produce an anode product, and an anode electrode to which a voltage is applied. Examples of the anode product include those containing oxygen and the like.

[0016] The separator is provided between the cathode 4 and the anode 7. The separator has a porous membrane that separates the cathode 4 and the anode 7. Examples of the porous membrane include a polyethersulfone (PES) filtration membrane, an ion exchange membrane, and the like. Note that the electrolysis cell stack 2 according to the present embodiment is configured as described above, but is not limited thereto. For example, an electrolysis cell stack that flows a gas and an electrolytic solution to either the anode or the cathode electrode and applies a voltage for electrolysis may be used.

[0017] The carbon dioxide-containing gas supply device 3 supplies a gas. The gas is, for example, carbon dioxide gas. The carbon dioxide-containing gas supply device 3 may have a gas cylinder that stores carbon dioxide gas and a pressure reducing valve that controls the pressure of the gas.

[0018] The carbon dioxide-containing gas supply pipe 5 connects the carbon dioxide-containing gas supply device 3, the humidifier 12, and the inlet of the cathode 4. This carbon dioxide-containing gas supply pipe 5 is connected to an insulator pipe 5a, a good conductor pipe 5b, and an insulator pipe 5c.

[0019] The insulator pipe 5c is a pipe that contacts the electrolysis cell stack 2. A good conductor pipe and an insulator pipe may be further connected to the carbon dioxide-containing gas supply device 3 side of the insulator pipe 5c. The carbon dioxide-containing gas supply pipe 5 supplies the carbon dioxide-containing gas to the cathode 4 of the electrolysis cell stack 2 through the humidifier 12 in such a connection form.

[0020] The electrolytic solution supply device 6 can supply an electrolytic solution. The electrolytic solution contains an ionic substance. The ionic substance is, for example, hydroxide ions (OH + ), hydrogen ions (H + ), potassium ions (K + ), lithium ions (Li +) and bicarbonate ions (HCO3) - At least one of the above is preferred. The electrolyte contains water. The electrolyte supply device 6 may have a pump.

[0021] The electrolyte supply piping 8 connects the electrolyte supply device 6 to the inlet of the anode 7. This electrolyte supply piping 8 is connected to an insulating pipe 8a, a good conductive pipe 8b, and an insulating pipe 8c.

[0022] The insulated pipe 8c is the pipe that is in contact with the electrolysis cell stack 2. At least one of a good conductive pipe or an insulated pipe may be further connected to the electrolyte supply device 6 side of the insulated pipe 8c. The electrolyte supply pipe 8 supplies the electrolyte to the cathode 4 of the electrolysis cell stack 2 in this connection configuration.

[0023] The carbon dioxide-containing gas discharge pipe 9 is connected to the outlet of cathode 4. This carbon dioxide-containing gas discharge pipe 9 is connected to an insulating pipe 9a, a good conductor pipe 9b, and an insulating pipe 8c.

[0024] The insulated pipe 9a is the pipe that is in contact with the electrolysis cell stack 2. At least one of a good conductor pipe or an insulated pipe may be further connected to the discharge end side of the insulated pipe 9c. The carbon dioxide-containing gas discharge pipe 9 discharges the carbon dioxide-containing gas emitted from the cathode 4 in this connection configuration.

[0025] The electrolyte discharge pipe 10 is connected to the outlet of the anode 7. This electrolyte discharge pipe 10 is connected to an insulating pipe 10a, a good conductive pipe 10b, and an insulating pipe 10c.

[0026] The insulated pipe 10a is the pipe that is in contact with the electrolysis cell stack 2. At least one of a good conductor pipe or an insulated pipe may be further connected to the discharge end of the insulated pipe 10c. The electrolyte discharge pipe 10 discharges the oxygen-containing gas discharged from the anode 7 in this connection configuration.

[0027] Insulated pipes 5a, 5c, 8a, 8c, 9a, 9c, 10a, and 10c are insulated pipes in which the inside of the pipe is made of an electrical insulating material. Insulated pipes are made of an electrical insulating material, such as having the inside of the pipe coated with a resin such as Teflon. Alternatively, the entire pipe may be made of an electrical insulating material such as Teflon.

[0028] The good-conducting pipes 5b, 8b, 9b, and 10b are metallic conductors. That is, the good-conducting pipes 5b, 8b, 9b, and 10b are made of metals that exhibit conductivity and durability.

[0029] The pipe temperature controller 11 is installed in the good-conducting pipe 5b of the carbon dioxide-containing gas supply pipe 5. The pipe temperature controller 11 is composed of at least an insulated heater. The pipe temperature controller 11 has a structure attached to the heater that allows the current to be turned ON / OFF, such as a bimetallic thermostat. Alternatively, a thermometer may be fixed to the surface of the good-conducting pipe 5b, and the heater may be turned ON / OFF or the amount of heat generated by the heater may be controlled according to the temperature.

[0030] The pipe temperature regulator 11 wraps a heater, which consists of a series of semiconductor heating elements 11a with self-temperature control functions arranged in parallel, around the surface of the good-conducting pipe 5b. This allows the heater to increase its heat output as the surface temperature of the good-conducting pipe 5b decreases, thereby controlling the surface temperature of the good-conducting pipe to reach the target temperature.

[0031] The humidifier 12 humidifies the gas so that the water vapor pressure of the water vapor accompanying the carbon dioxide-containing gas reaches the saturation water vapor pressure (full humidification) at the temperature of the carbon dioxide-containing gas. This humidifier 12 is composed of, for example, a water tank, an electric heater, a thermometer, and a hollow fiber membrane.

[0032] The DC power supply 13 connects the anode electrode of the anode 7 to the positive side and the cathode electrode of the cathode 4 to the negative side. Thereby, the DC power supply 13 applies a positive voltage from the DC power supply 13 to the anode electrode of the anode 7. The negative side of the DC power supply 13 is grounded.

[0033] The good conductor pipes 5b, 8b, 9b, and 10b of the carbon dioxide-containing gas supply pipe 5, the electrolyte supply pipe 8, the carbon dioxide-containing gas discharge pipe 9, and the electrolyte discharge pipe 10 through which the electrolyte passes are all connected to the end of the cathode 4. Since the cathode 4 is connected to the ground, the good conductor pipes 5b, 8b, 9b, and 10b are all set to a predetermined reference potential, for example, 0 volts which is the ground potential. In some cases, the ground potential may be referred to as the earth potential. Also, the reference potential can be set within a range that suppresses leakage current for the potential of the substances flowing in the pipes 5b, 8b, 9b, 10b and in their vicinity.

[0034] With such a configuration, a DC power supply 13 that applies a voltage between the electrodes of the anode 7 and the cathode 4 is provided. By energizing the electrolytic cell stack, the carbon dioxide CO2 supplied to the cathode 4 is reduced to generate gases such as CO. Here, the reaction process when reducing carbon dioxide (CO₂) to generate hydroxide ions (OH - ) will be described.

[0035] When a current is supplied from the power control unit 40 between the anode 7 and the cathode 4, near the cathode 2, as shown in the following formula (1), water (H₂O) and carbon dioxide (CO₂) are reduced to generate carbon monoxide (CO) and hydroxide ions (OH - ). The hydroxide ions (OH - ) diffuse near the anode 7 and, as shown in the following formula (2), the hydroxide ions (OH - ) are oxidized to generate oxygen (O₂).

[0036] 2CO₂ + 2H₂O + 4e - →2CO + 4OH - (1) 4OH- →2H2O+O2+4e - (2) The electrolyte is a mixture of an ionic substance and a polar solvent. Alternatively, the system may be configured with the gas flowing through the anode and the electrolyte through the cathode.

[0037] The control device 20 functions as a control center for controlling the operation of the electrolysis system 1. The control device 20 is a microcomputer equipped with resources such as a CPU, memory, and input / output devices. The control device 20 reads signals from various sensors (not shown) installed in the electrolysis system 1. Based on the various signals it has read and the control logic (program) it has pre-programmed internally, it sends commands to each component of the electrolysis system 1, such as the carbon dioxide-containing gas supply device 3, the electrolyte supply device 6, the pipe temperature regulator 11, the humidifier 12, and the DC power supply device 13. In this way, the control device 20 comprehensively manages and controls all operations necessary for the operation and stopping of the electrolysis system 1.

[0038] Even if the carbon dioxide-containing gas supply device 3 is constructed of conductive stainless steel, the leakage current from the electrolysis cell stack 2 will not corrode the stainless steel and leach impurities, thus eliminating the risk of impurities contaminating the electrolysis cell stack 2 and causing its deterioration. On the other hand, since the electrolyte supply device 6, electrolyte supply piping 8, and electrolyte discharge piping 9 contain liquid, the wetted parts are constructed of resin materials such as PP, PE, or PVC.

[0039] Since carbon dioxide-containing gas discharge piping 9 carries flammable gases such as carbon monoxide (CO) and hydrogen, connections between the airtight piping and the piping and equipment should be made using flanges, threaded fittings with sealing tape, or Swagelok fittings or Fujikin V-lok fittings. Furthermore, to prevent the generation of static electricity, all piping should be connected to ground. Because the sealing materials at the connections, such as flange gaskets and sealing tape, are not conductive, jumper wiring should be installed between the piping and equipment, and all piping and equipment carrying hydrogen should be connected to ground.

[0040] When a narrow pipe is connected to the center of a wide pipe, condensed water can accumulate in the wide pipe up to the hole in the narrow pipe, causing irregular flow of condensed water. This can lead to irregular gas supply and increase the risk of rust formation in the pipe due to convection. When connecting a narrow pipe to a wide pipe, an eccentric reducer should be used to ensure that condensed water generated upstream flows into the narrow pipe downstream without accumulating.

[0041] [1-2 action] The operation according to this embodiment will now be explained. When electrolysis is performed by applying a high voltage, in order to prevent electrical leakage through the electrolyte flowing from the electrolysis cell stack 2 to the electrolyte supply pipe 8, an insulating pipe 8c, whose interior is made of an electrical insulating material, is connected to the electrolysis cell stack 2. Furthermore, a good conductor pipe 8b is connected to the insulating pipe 8c, and the good conductor pipe 8b is connected to earth along with the negative side of the DC power supply device 13. As a result, the potential between the good conductor pipe 8b and the electrolyte near the good conductor pipe 8b approaches the reference potential of zero volts.

[0042] To prevent electrical leakage via moisture in the carbon dioxide gas flowing from the electrolysis cell stack 2 to the carbon dioxide gas supply pipe 5 when electrolysis is performed by applying a high voltage, an insulating pipe 5c made of electrical insulating material of the carbon dioxide gas supply pipe 5 is connected to the electrolysis cell stack 2. Furthermore, a good conductor pipe 5b is connected to the insulating pipe 5c, and the good conductor pipe 5b is connected to earth. As a result, the potential between the good conductor pipe 5b and the carbon dioxide and moisture near the good conductor pipe 5b approaches the reference potential of zero volts.

[0043] The parts in contact with the electrolysis cell stack 2, both upstream and downstream, including cathode 4 and anode 7, are insulated pipes 5c, 8c, 9a, and 10a, which are connected to good-conducting pipes 5b, 8b, 9b, and 10b, and further connected to insulated pipes 5a, 8a, 9c, and 10c. This prevents leakage current from the electrolysis cell stack 2 from being transmitted to the insulated pipes 5a, 8a, 9c, and 10c, which are not in contact with the electrolysis cell stack 2, when the potential of the good-conducting pipes 5b, 8b, 9b, and 10b and the electrolyte, carbon dioxide gas, or moisture near the good-conducting pipes 5b, 8b, 9b, and 10b is not zero, due to the ground connection of the good-conducting pipes 5b, 8b, 9b, and 10b.

[0044] The good-conducting pipe 5b between the insulated pipes 5a and 5c is heated by equipping it with a pipe temperature controller 11.

[0045] Figure 2 is a flowchart showing an example of control by the control device 20. The control device 20 drives the carbon dioxide-containing gas supply device 3 and the electrolyte supply device 6 while the good conductive pipes 5b, 8b, 9b, and 10b are set to a predetermined reference potential (e.g., ground potential) (step S100).

[0046] Next, the control device 20 starts supplying power to the DC power supply unit 13 (step S102). With the good conductive pipes 5b, 8b, 9b, and 10b at ground potential, the electrolysis cell stack 2 starts electrolysis (step S104). The control device 20 terminates the control process after a predetermined time has elapsed.

[0047] As a result, with the potential of the good conductive pipes 5b, 8b, 9b, and 10b and their surroundings approaching zero, the electrolysis cell stack 2 becomes electrically charged, and leakage current from the electrolysis cell stack 2 is suppressed.

[0048] [Effects 1-3] The effects of this embodiment will now be explained. The insulating pipe 8c of the electrolyte supply pipe 8, which is made of electrical insulating material, is connected to the electrolysis cell stack 2. Furthermore, a good conductor pipe 8b is connected to the insulating pipe 8c, and the good conductor pipe 8b is connected to earth via the negative side of the DC power supply device 13. This makes it possible to bring the potential between the good conductor pipe 8b and the electrolyte near the good conductor pipe 8b closer to the reference potential of zero volts, thereby suppressing leakage current. As a result, it is possible to prevent the good conductor pipe 8b of the electrolyte supply pipe 8 from corroding and leaching impurities due to leakage current.

[0049] The insulating pipe 5c, made of electrical insulating material, of the carbon dioxide-containing gas supply pipe 5 is connected to the electrolysis cell stack 2. Furthermore, a good conductor pipe 5b is connected to the insulating pipe 5a, and the good conductor pipe 5b is connected to ground via the negative side of the DC power supply unit 13. This makes it possible to bring the potential between the good conductor pipe 5b and the carbon dioxide and moisture near the good conductor pipe 5b close to zero, thereby suppressing leakage current. As a result, it is possible to prevent corrosion of the good conductor pipe 5b of the carbon dioxide-containing gas supply pipe 5 and the leaching of impurities due to leakage current.

[0050] The parts in contact with the electrolysis cell stack 2, both upstream and downstream, as well as cathode 4 and anode 7, are insulated pipes 5c, 8c, 9a, and 10a, which are connected to good conductive pipes 5b, 8b, 9b, and 10b, and further connected to insulated pipes 5a, 8a, 9c, and 10c. This prevents corrosion and leaching of impurities from the insulated pipes 5a, 5c, 8a, 8c, 9a, 9c, 10a, and 10b due to leakage current from the electrolysis cell stack 2.

[0051] By equipping the good-conducting pipe 5b between the insulated pipes 5a and 5c with a pipe temperature controller 11 and heating the good-conducting pipe 5b, it is possible to maintain the temperature of the humidifying gas and prevent its condensation. In other words, because the good-conducting pipe 5b has a fast heating response, it is easier to prevent the condensation of the humidifying gas. Furthermore, even if insulation material is wrapped around it, it is not possible to reduce the amount of heat radiated from the pipe to zero, so the good-conducting pipe 5b can be heated to a temperature higher than that of the humidifying gas.

[0052] (Second Embodiment) The electrolysis system 1 according to the second embodiment differs from the electrolysis system 1 according to the first embodiment in that it further includes a ground fault detection unit 14. The differences from the electrolysis system 1 according to the first embodiment will be explained below.

[0053] [2-1 structure] The configuration of a second embodiment of the present invention will be described with reference to Figure 3. Figure 3 is a diagram showing an example of the configuration of the electrolysis system 1 according to the second embodiment. As shown in Figure 3, a ground fault detection unit 14 is provided between the negative side of the DC power supply unit 13 to which the end of the cathode 4 of the electrolysis cell stack 2 is connected and the earth ground. It is desirable that this ground fault detection unit 14 be a passive type ground fault detection with a large resistance so as to be able to easily detect leakage current of DC voltage. For example, the ground fault detection unit 14 can detect voltage changes and current changes by grounding two high-resistance neutral points.

[0054] [2-2 action]

[0055] The operation of Embodiment 2 of the present invention will be explained, focusing on the differences between Embodiment 1 and Embodiment 2. By using the ground fault detection unit 14, the current value of the ground fault current is suppressed during a ground fault.

[0056] [2-3 effects]

[0057] The effects of Embodiment 2 of the present invention will be explained, focusing on the differences from Embodiment 1. By using the ground fault detection unit 14, leakage current can be detected, preventing failure of electrical equipment such as the DC power supply unit 13. When a ground fault occurs, the current value of the ground fault current is suppressed, and since Joule heating is the product of voltage and current, a lower current value reduces the amount of heat generated when a ground fault occurs, making it possible to further suppress ignition.

[0058] (Third embodiment) The electrolysis system 1 according to the third embodiment differs from the electrolysis system 1 according to the first embodiment in that it includes an electrolyte cell stack inlet thermometer 15 that measures the temperature of the electrolyte before it enters the electrolysis cell stack 2. The differences from the electrolysis system 1 according to the first embodiment will be explained below.

[0059] [3-1 Structure] Figure 4 shows an example of the configuration of the electrolysis system 1 according to the third embodiment. As shown in Figure 4, it is equipped with an electrolyte cell stack inlet thermometer 15 that measures the temperature of the electrolyte before it enters the electrolysis cell stack 2.

[0060] [3-2 action]

[0061] The control unit 20 controls the pipe temperature regulator 11 according to the temperature measured by the electrolyte cell stack inlet thermometer 15. For example, the control unit 20 controls the pipe temperature regulator 11 so that the surface temperature of the good conductive pipe 5b is equal to or higher than the temperature measured by the electrolyte cell stack inlet thermometer 15.

[0062] [3-3 Effect]

[0063] The temperature of the electrolyte before it enters the electrolysis cell stack 2, as measured by the electrolyte cell stack inlet thermometer 15, is dominant over the temperature of the electrolysis cell stack 2. By heating the good conductive piping 5b in accordance with the temperature of the electrolysis cell stack 2, it is possible to prevent the condensation of water vapor accompanying the carbon dioxide gas entering the cell stack within the piping.

[0064] (Fourth Embodiment) The electrolysis system 1 according to the fourth embodiment differs from the electrolysis system 1 according to the third embodiment in that a pipe temperature regulator 11c is also installed in the insulated pipe 5a. The differences from the electrolysis system 1 according to the third embodiment will be explained below.

[0065] [4-1 Composition]

[0066] Figure 5 shows an example of the configuration of the electrolysis system 1 according to the fourth embodiment. As shown in Figure 5, the insulating pipe 5a has a metal part in part, and the pipe temperature controller 11c also heats the metal part. Alternatively, the insulating pipe 5c may also have a metal part in part, and the pipe temperature controller 11c may also heat the insulating pipe 5c. Heaters, which are semiconductor heating elements 11b with a self-temperature control function, arranged in a continuous parallel circuit, may be wrapped around the surface of the metal parts of the insulating pipes 5a and 5c.

[0067] [4-2 action] In the electrolysis system 1 according to the third embodiment, the pipe temperature controller 11 is installed only in the good conductive pipe 5b, but by installing the pipe temperature controller 11c in the insulated pipes 5a and 5c, which have a metal with good thermal conductivity on their outer surface and are made of insulating material inside, heating can also be performed in the insulated pipes.

[0068] [4-3 Effects] Insulated piping 5a and 5c, which are entirely made of insulating material, are difficult to use with the piping temperature controller 11c due to heat resistance considerations, but they can prevent condensation due to heat dissipation from carbon dioxide gas and its accompanying moisture. This prevents droplets from clogging the electrolysis cells of the electrolysis cell stack 2 and inhibiting the electrochemical reaction of the electrolysis cells. Because the humidity of the gas is reduced by the amount of condensation, it is possible to prevent localized drying of the diaphragm of the electrolysis cell.

[0069] (Fifth embodiment) The electrolysis system 1 according to the fifth embodiment differs from the electrolysis system 1 according to the third embodiment in that it further includes a carbon-containing gas inlet thermometer 16 for measuring the temperature of the electrolyte before it enters the electrolysis cell stack 2. The differences from the electrolysis system 1 according to the third embodiment will be explained below.

[0070] [5-1 Composition] Figure 6 shows an example of the configuration of the electrolysis system 1 according to the fifth embodiment. As shown in Figure 6, it is equipped with an electrolyte cell stack inlet thermometer 15 and a carbon-containing gas inlet thermometer 16 for measuring the temperature of the electrolyte before it enters the electrolysis cell stack 2. The inlet thermometers 15 and 16 can measure the surface temperature of the good conductive pipes 5b and 8b.

[0071] [5-2 action]

[0072] The control unit 20 controls the piping temperature controller 11 according to the temperatures measured by the inlet thermometers 15 and 16. For example, the control unit 20 controls the system so that the electrolyte inlet temperature at the inlet of the electrolysis cell stack 2 is equal to the inlet temperature of the fully humidified CO2 at the inlet of the electrolysis cell stack 2.

[0073] [5-3 Effect]

[0074] Even if insulation is wrapped around the piping 5, heat loss cannot be completely eliminated. For example, even if the humidifier 12 controls the humidified water temperature, it becomes difficult to control the electrolyte inlet temperature and the fully humidified CO2 temperature to be equal. In contrast, the control unit 20 controls the piping temperature regulator 11 according to the temperatures measured by the electrolyte cell stack inlet thermometer 15 and the carbon-containing gas inlet thermometer 16, making it possible to control the electrolyte inlet temperature and the fully humidified CO2 inlet temperature to be as close as possible.

[0075] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of 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 in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of symbols]

[0076] 1... Electrolysis system, 2... Electrolysis cell stack, 3... Carbon dioxide-containing gas supply device, 4... Cathode, 5... Carbon dioxide-containing gas supply piping, 6... Electrolyte supply device, 7... Anode, 8... Electrolyte supply piping, 9... Carbon dioxide-containing gas discharge piping, 10... Electrolyte discharge piping, 5b, 8b, 9b, 10b... Good conductive piping, 5a, 5c, 8a, 8c, 9a, 9c, 10a, 10c... Insulated piping, 11... Piping temperature regulator, 12... Humidifier, 13... DC power supply unit, 14... Ground fault detection unit, 15... Electrolyte cell stack inlet thermometer, 16... Carbon dioxide-containing gas inlet thermometer

Claims

1. An electrolysis cell stack that performs electrolysis by passing gas and electrolyte through either the anode or cathode electrode and applying a voltage, A power supply device that applies a voltage between the anode electrode and the cathode electrode of the electrolysis cell stack, A gas supply device that supplies the gas to one electrode, An electrolyte supply device that supplies the electrolyte to the other electrode, A supply pipe for supplying anode fluid and cathode fluid to the electrolysis cell stack, A discharge pipe for discharging anode fluid and cathode fluid from the electrolysis cell stack, In an electrolysis system equipped with, An electrolysis system in which at least one of the supply pipe and the discharge pipe has a plurality of insulating pipes whose interiors are made of an electrical insulating material, and a good conductor pipe of good conductors connected between the plurality of insulating pipes, and the good conductor pipe is set to a predetermined reference potential.

2. The electrolysis system according to claim 1, wherein the predetermined reference potential is the ground potential.

3. The electrolysis system according to claim 2, wherein the good conductive piping is connected to the cathode of the electrolysis cell stack.

4. It further includes a passive ground fault detection unit connected to the earth, The electrolysis system according to claim 2, wherein the good conductive piping is connected to the earth via the ground fault detection unit.

5. The supply pipe on the side that supplies cathode fluid within the supply pipe comprises a plurality of insulating pipes whose interiors are made of electrical insulating material, and a good conductive pipe made of good conductors connected between the plurality of insulating pipes. A pipe temperature controller, which is placed in the aforementioned good conductive piping and is insulated, The electrolysis system according to claim 1, further comprising:

6. A first inlet thermometer measures the temperature of the electrolyte before it enters the electrolysis cell stack, A control unit controls the pipe temperature regulator according to the temperature measured by the first inlet thermometer, The electrolysis system according to claim 5, further comprising the following:

7. The system further includes a second inlet thermometer for measuring the temperature of the gas before it enters the electrolysis cell stack. The electrolysis system according to claim 6, wherein the control unit controls the temperature at which the electrolyte enters the electrolysis cell stack to match the temperature at which the gas enters the electrolysis cell stack, based on the temperature of the first inlet thermometer and the temperature of the second inlet thermometer.

8. An electrolysis cell stack that performs electrolysis by passing gas and electrolyte through either the anode or cathode electrode and applying a voltage, A power supply device that applies a voltage between the anode electrode and the cathode electrode of the electrolysis cell stack, A gas supply device that supplies the gas to one electrode, An electrolyte supply device that supplies the electrolyte to the other electrode, A supply pipe for supplying anode fluid and cathode fluid to the electrolysis cell stack, A discharge pipe for discharging anode fluid and cathode fluid from the electrolysis cell stack, In an electrolysis system equipped with, An electrolysis method for an electrolysis system, wherein at least one of the supply pipe and the discharge pipe comprises a plurality of insulating pipes whose interiors are made of an electrical insulating material, and a good conductor pipe of good conductors connected between the plurality of insulating pipes, An electrolysis method comprising driving the power supply device, the gas supply device, and the electrolyte supply device while the good conductive piping is at a predetermined reference potential.

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