Electrolysis module cooling method and electrolysis system

Abstract

Provided are an electrolysis module cooling method and an electrolysis system capable of reducing an atmospheric temperature inside a container. Provided is a cooling method for an electrolysis module (200) comprising: at least one electrolysis cartridge (220) that includes an electrolysis cell and generates hydrogen by electrolyzing water vapor generated from water supply; and a pressure vessel (210) that accommodates the electrolysis cartridge (220). In the method for cooling the electrolysis module (200), the air is subjected to heat exchange with water supply in order to heat the water supply, and the heat-exchanged air is supplied to the pressure vessel (210) to cool the inside of the pressure vessel (210).

Description

Electrolysis module cooling method and electrolysis system

[0001] The present disclosure relates to a cooling method for an electrolysis module and an electrolysis system.

[0002] For example, Patent Document 1 discloses a steam electrolysis system that generates hydrogen by steam electrolysis. The system disclosed in Patent Document 1 includes a module having a solid oxide electrolysis cell (SOEC).

[0003] Japanese Patent No. 7282968 Japanese Patent Application Laid-Open No. 2018-133305

[0004] In a steam electrolysis system, the atmospheric temperature inside the pressure vessel is, for example, approximately 400°C to 450°C. This requires the use of highly heat-resistant materials, such as stainless steel instead of carbon steel for the structural members housed inside the vessel, and nickel instead of copper-based materials for the current-carrying members, which increases equipment costs. Therefore, reducing equipment costs is necessary to reduce the unit price of hydrogen production, and studies are being conducted to reduce the atmospheric temperature inside the pressure vessel in order to reduce equipment costs by using relatively inexpensive materials that are not highly heat-resistant as materials for the structural members housed inside the pressure vessel.

[0005] On the other hand, for the sake of efficiency, it is desirable to increase the pressure of the entire steam electrolysis system (for example, about 3 MPa to 5 MPa), and it is estimated that increasing the pressure of the system will increase the atmospheric temperature inside the pressure vessel, so reducing the atmospheric temperature is also necessary as a countermeasure. The reason why it is desirable to increase the pressure of the steam electrolysis system is as follows: The hydrogen produced is often ultimately used at high pressure, and it requires less power to pressurize the raw material water than to pressurize the produced hydrogen.

[0006] The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide an electrolysis module cooling method and an electrolysis system that can reduce the atmospheric temperature inside a container.

[0007] In order to solve the above problems, the electrolysis module cooling method and electrolysis system of the present disclosure employ the following measures: A cooling method for an electrolysis module according to one aspect of the present disclosure is a method for cooling an electrolysis module comprising: an electrolysis cell having a hydrogen electrode, an oxygen electrode, and an electrolyte layer disposed between the hydrogen electrode and the oxygen electrode, at least one electrolysis cartridge that produces hydrogen by electrolyzing water vapor generated from feed water; and a container that houses the electrolysis cartridge, the method comprising: exchanging heat between a heat transfer gas and the feed water to heat the feed water; and supplying the heat-exchanged heat transfer gas to the container to cool the interior of the container.

[0008] An electrolysis system according to an aspect of the present disclosure includes an electrolysis module, a heat exchanger, and a heat transfer gas supply line. The electrolysis module has at least one electrolysis cartridge and a container. The electrolysis cartridge includes an electrolysis cell having a hydrogen electrode, an oxygen electrode, and an electrolyte layer disposed between the hydrogen electrode and the oxygen electrode. The electrolysis system generates hydrogen by electrolyzing water vapor generated from feedwater. The container accommodates the electrolysis cartridge. The heat transfer gas supply line is a line through which a heat transfer gas flows. The heat transfer gas is supplied to the heat exchanger as a heat source for heating the feedwater, and the heat transfer gas that has been heat exchanged in the heat exchanger is supplied to the container.

[0009] According to the present disclosure, the ambient temperature inside the container can be reduced.

[0010] FIG. 1 is a schematic configuration diagram of a steam electrolysis system according to a first embodiment of the present disclosure. FIG. 2 is a schematic configuration diagram of an electrolysis module included in the steam electrolysis system shown in FIG. 1 . FIG. 3 is a side view of an electrolysis cartridge included in the electrolysis module. FIG. 4 is a front view of the electrolysis cartridge shown in FIG. 5 . FIG. 5 is a schematic diagram showing the structure of the electrolysis cartridge shown in FIG. 4 . FIG. 6 is a partial enlarged cross-sectional view of a cell stack in the vicinity of the electrolysis cell shown in FIG. 5 . FIG. 6 is a schematic diagram of an electrolysis cartridge included in the electrolysis module shown in FIG. 2 . FIG. 7 is a schematic configuration diagram of an electrolysis module included in the steam electrolysis system shown in FIG. 1 (Another Example 1). FIG. 8 is a schematic configuration diagram of an electrolysis module included in the steam electrolysis system shown in FIG. 1 (Another Example 2). FIG. 9 is a schematic configuration diagram of a steam electrolysis system according to a second embodiment of the present disclosure. FIG. 10 is a schematic configuration diagram of an electrolysis module included in the steam electrolysis system shown in FIG. 10 . FIG. 11 is a schematic configuration diagram of a steam electrolysis system according to a fourth embodiment of the present disclosure. FIG. 12 is a schematic configuration diagram of a steam electrolysis system according to a fifth embodiment of the present disclosure.

[0011] Cooling methods for electrolysis modules and electrolysis systems according to first to fifth embodiments of the present disclosure will be described below with reference to the drawings. Note that the terms "height direction," "depth direction," and "width direction" are used for descriptive purposes and do not limit the actual orientations of the electrolysis modules and steam electrolysis systems. Furthermore, the "height direction," "depth direction," and "width direction" are perpendicular to one another.

[0012] [First embodiment] <System overview> A steam electrolysis system 10, as an example of an electrolysis system, is a system that produces hydrogen by heating feedwater to produce steam and electrolyzing the generated steam under high temperature and high pressure. As shown in Fig. 1 , the steam electrolysis system 10 includes an electrolysis module 200, multiple heat exchangers L11, L41, and L51, a compression device 120, a water supply device 130, a power supply device 140, and lines (piping systems) connecting the various devices / equipment to one another.

[0013] The electrolysis module 200 is a device that performs steam electrolysis. Although details will be described later, the electrolysis module 200 is generally a device that electrolyzes supplied steam under high temperature and high pressure.

[0014] Each of the heat exchangers L11, L41, and L51 is a device that heats feedwater and / or heats feedwater to generate steam that is supplied to the electrolysis module 200.

[0015] The compression device 120 compresses the heat transfer gas supplied to the electrolysis module 200. An example of the heat transfer gas is an oxidizing gas such as air. In the following description, the heat transfer gas is air. The compression device 120 includes a compressor 121, a turbine 122, and an electric motor 123. The compressor 121 and the turbine 122 are connected by the same rotating shaft, and the compressor 121 is driven by the rotation of the turbine 122. The electric motor 123 is configured to drive the compressor 121 or assist in driving the compressor 121 when the output of the turbine 122 is low (for example, during startup of the steam electrolysis system 10).

[0016] The water supply device 130 is a device that stores and supplies water (feed water). This feed water is heated in each of the heat exchangers L11, L41, and L51 to become steam. The power supply device 140 is a device that supplies power to the electrolysis module 200 to be used for steam electrolysis.

[0017] The compressor 121 of the compression device 120 is connected to the electrolysis module 200 via an air supply primary line L10. That is, the air supply primary line L10 connects the compressor 121 and the electrolysis module 200. High-temperature, high-pressure air compressed by the compressor 121 is supplied to the electrolysis module 200 via the air supply primary line L10. A heat exchanger L11 is provided in the air supply primary line L10. The heat exchanger L11 serves as a heat source for heating the feedwater. Therefore, the air supplied to the electrolysis module 200 has undergone heat exchange with the feedwater, and its temperature is lower than the temperature before the heat exchange (e.g., approximately 300°C to 400°C), e.g., approximately 200°C to 300°C.

[0018] The turbine 122 of the compression device 120 is connected to the electrolysis module 200 via an oxygen-enriched air discharge line L50. That is, the oxygen-enriched air discharge line L50 connects the turbine 122 and the electrolysis module 200. The high-temperature, high-pressure oxygen-enriched air discharged from the electrolysis module 200 is guided to the turbine 122 via the oxygen-enriched air discharge line L50, and drives the turbine 122 to rotate. A heat exchanger L51 is provided in the oxygen-enriched air discharge line L50. The heat exchanger L51 serves as a heat source for heating the feedwater.

[0019] A hydrogen discharge line L40 is connected to the electrolysis module 200. High-temperature, high-pressure hydrogen generated and discharged from the electrolysis module 200, as well as some water vapor (water vapor that remains unelectrolyzed), are supplied to the outside of the electrolysis module 200 (e.g., a facility for storing hydrogen) via the hydrogen discharge line L40. A heat exchanger L41 is provided in the hydrogen discharge line L40. The heat exchanger L41 serves as a heat source for heating feedwater.

[0020] The water supply device 130 is connected to the electrolysis module 200 via a water / steam supply line L30. That is, the water / steam supply line L30 connects the water supply device 130 and the electrolysis module 200. For example, heat exchangers L11, L51, and L41 are provided in parallel on the water / steam supply line L30. The feedwater flowing through the water / steam supply line L30 is heated and converted into steam while passing through the heat exchangers L11, L41, and L51. That is, the feedwater delivered from the water supply device 130 is heated and converted into steam in the heat exchangers L11, L41, and L51, and the generated high-temperature steam is supplied to the electrolysis module 200. As described above, the heat sources for heating the feedwater are the air flowing through the heat exchanger L11, the oxygen-enriched air flowing through the heat exchanger L51, and the hydrogen flowing through the heat exchanger L41. It should be noted that other heat exchangers (through which a fluid for heating the feedwater flows) than the heat exchangers L11, L51, and L41 may be further provided in the water / steam supply line L30. Furthermore, the heat exchangers may be provided in series in the water / steam supply line L30. Furthermore, only some of the heat exchangers may be provided in parallel in the water / steam supply line L30, and the remaining heat exchangers may be provided in series.

[0021] <Details of Electrolysis Module> As shown in FIG. 2 , the electrolysis module 200 includes a pressure vessel 210 , a plurality of electrolysis cartridges 220 , a submodule heat insulating material 240 , a main supply pipe 251 , and a main discharge pipe 252 .

[0022] The pressure vessel 210 is a metal vessel having an internal space. An insulating material (heat-retaining material) may be applied to the inner surface of the pressure vessel 210. The pressure vessel 210 contains a sub-module including a plurality of electrolysis cartridges 220 and a sub-module insulating material 240 provided around the electrolysis cartridges 220.

[0023] The detailed configuration of the electrolytic cartridge 220 will be described with reference to Figures 3 to 6. Figure 3 is a side view of the electrolytic cartridge 220. Figure 4 is a front view of the electrolytic cartridge 220 shown in Figure 3. Figure 5 is a schematic diagram of the electrolytic cartridge shown in Figure 4. Figure 6 is a partially enlarged cross-sectional view of the cell stack 230 near the electrolytic cell 232 shown in Figure 5.

[0024] As shown in Figures 3, 4, and 5, the electrolysis cartridge 220 includes a plurality of cell stacks 230, a water vapor supply header 221a, a hydrogen discharge header 221c, an air supply header 222a, an oxygen-enriched air discharge header 222c, and a cartridge insulator 223.

[0025] As shown in Fig. 6 , each cell stack 230 is a cylindrical component extending in the height direction, and includes a base tube 231, a solid oxide electrolysis cell 232 (hereinafter simply referred to as an "electrolysis cell 232"), an interconnector 233, and a lead film 234. The base tube 231 is a cylindrical tube extending in the axial direction and formed from a porous material. A plurality of electrolysis cells 232 and interconnectors 233 formed between adjacent electrolysis cells 232 are formed on the outer circumferential surface of the base tube 231. The electrolysis cell 232 includes a hydrogen electrode 232a as a cathode, an oxygen electrode 232b as an anode, and an electrolyte layer 232c provided between the hydrogen electrode 232a and the oxygen electrode 232b. Of the multiple electrolytic cells 232 formed on the outer peripheral surface of the base tube 231, a lead film 234 is provided that is electrically connected via an interconnector 233 to the oxygen electrode 232b of the electrolytic cell 232 formed at the end in the axial direction of the base tube 231, and a lead film 234 is provided that is electrically connected to the hydrogen electrode 232a of the electrolytic cell 232 formed at the other end of the most extreme end. The lead film 234 supplies DC power to the multiple electrolytic cells 232 connected in series via the interconnector 233.

[0026] When external power is supplied between the hydrogen electrode 232a and the oxygen electrode 232b via the lead film 234, some of the high-temperature water vapor supplied to the hydrogen electrode 232a receives electrons and is separated into hydrogen and oxygen ions, generating hydrogen. The separated oxygen ions move inside the electrolyte layer 232c to the oxygen electrode 232b, where they release electrons and generate oxygen.

[0027] The multiple cell stacks 230 configured as described above are arranged at intervals in the depth and width directions, for example, with the axial direction coinciding with the height direction, as shown in Figures 3, 4 and 5.

[0028] A water vapor supply header 221a is provided at the top of the multiple cell stacks 230, and a hydrogen discharge header 221c is provided at the bottom of the multiple cell stacks 230. The space defined by the water vapor supply header 221a is connected to the space inside each cell stack 230 (the space inside the base tube 231) at the top end of the cell stack 230. The space defined by the hydrogen discharge header 221c is connected to the space inside each cell stack 230 at the bottom end of the cell stack 230. In other words, the space defined by the water vapor supply header 221a and the space defined by the hydrogen discharge header 221c are connected via the space inside each cell stack 230.

[0029] A water vapor supply pipe 221b, which is connected to the water / steam supply line L30, is connected to the water vapor supply header 221a, and the water vapor supply header 221a is configured to receive high-temperature water vapor from the water / steam supply line L30. The water vapor introduced into the water vapor supply header 221a flows into a space inside the cell stack 230 and flows toward the hydrogen discharge header 221c. In the process, the water vapor is electrolyzed in the cell stack 230, and high-temperature hydrogen generated by the electrolysis and some of the water vapor that remains unelectrolyzed are introduced to the hydrogen discharge header 221c. A hydrogen discharge pipe 221d, which is connected to the hydrogen discharge line L40, is connected to the hydrogen discharge header 221c, and the hydrogen discharge header 221c is configured to discharge the generated hydrogen and some of the water vapor into the hydrogen discharge line L40.

[0030] An air supply header 222a is provided adjacent to the upper surface of the hydrogen discharge header 221c at the bottom of the multiple cell stacks 230, and an oxygen-enriched air discharge header 222c is provided adjacent to the lower surface of the water vapor supply header 221a at the top of the multiple cell stacks 230. Neither the space defined by the air supply header 222a nor the space defined by the oxygen-enriched air discharge header 222c communicates with the space inside each cell stack 230 (the space inside the substrate tube 231).

[0031] A cartridge insulation 223 is provided between the air supply header 222a and the oxygen-enriched air discharge header 222c, which are spaced apart in the vertical direction. The cartridge insulation 223 includes a cartridge peripheral insulation section 223a, a cartridge upper insulation section 223b, and a cartridge lower insulation section 223c. However, each insulation section may be integrally formed. The cartridge peripheral insulation section 223a is an insulation material that surrounds a group or cluster of multiple cell stacks 230. A gap (space) is provided between the cartridge peripheral insulation section 223a and the cell stacks 230. Note that the cartridge peripheral insulation section 223a does not surround each individual cell stack 230. The cartridge upper insulation section 223b is an insulation material interposed between the cartridge peripheral insulation section 223a and the oxygen-enriched air discharge header 222c. Each cell stack 230 is inserted into the cartridge upper insulation section 223b. An exhaust flow path 223b1 through which oxygen-enriched air flows is provided between the cartridge upper insulation part 223b and each cell stack 230. The cartridge lower insulation part 223c is an insulating material interposed between the cartridge peripheral insulation part 223a and the air supply header 222a. Each cell stack 230 is inserted into the cartridge lower insulation part 223c. A supply flow path 223c1 through which air flows is provided between the cartridge lower insulation part 223c and each cell stack 230.

[0032] The cartridge peripheral insulation section 223a, the cartridge upper insulation section 223b, and the cartridge lower insulation section 223c of the cartridge insulation material 223 define an electrolysis chamber (reaction chamber) 224. All of the electrolysis cells 232 formed on the outer peripheral surface of each cell stack 230 are housed in this reaction chamber 224. The reaction chamber 224 communicates with the space defined by the oxygen-enriched air discharge header 222c via the discharge flow path 223b1. The reaction chamber 224 also communicates with the space defined by the air supply header 222a via the supply flow path 223c1. In other words, the space defined by the air supply header 222a and the space defined by the oxygen-enriched air discharge header 222c are communicated with each other via the supply flow path 223c1, the reaction chamber 224, and the discharge flow path 223b1.

[0033] An air supply pipe 222b connected to the air supply primary line L10 is connected to the air supply header 222a, and the air supply header 222a is configured to receive air from the air supply primary line L10. The air introduced to the air supply header 222a flows into the reaction chamber 224 via a supply flow path 223c1 and toward the oxygen-enriched air discharge header 222c. During this process, oxygen generated by steam electrolysis mixes with the air supplied from the air supply primary line L10 and is introduced to the oxygen-enriched air discharge header 222c via a discharge flow path 223b1. The mixture of the generated oxygen and the supplied air is referred to as oxygen-enriched air. An oxygen-enriched air discharge pipe 222d connected to the oxygen-enriched air discharge line L50 is connected to the oxygen-enriched air discharge header 222c, and the oxygen-enriched air discharge header 222c is configured to discharge the oxygen-enriched air into the oxygen-enriched air discharge line L50.

[0034] The air and / or oxygen-enriched air flowing through the reaction chamber 224 removes heat from the cell stack 230, which has become hot (e.g., about 700°C to 1000°C) due to the electrolytic reaction, thereby cooling the cell stack 230 and, ultimately, the electrolytic cartridge 220.

[0035] 7, in this embodiment, the air supply header 222a and air supply pipe 222b of the electrolytic cartridge 220 are omitted. In this case, the primary air supply line L10 is not connected to the air supply pipe 222b, and is configured to supply air to the inside of the pressure vessel 210. The air supplied to the inside of the pressure vessel 210 via the primary air supply line L10 is then taken into the reaction chamber 224 via the supply flow path 223c1.

[0036] 2, the plurality of electrolytic cartridges 220 are provided with a sub-module heat insulating material (enclosure member) 240. Hereinafter, the plurality of electrolytic cartridges 220 and the sub-module heat insulating material 240 are defined as a sub-module.

[0037] The submodule thermal insulation 240 includes at least one of a submodule peripheral insulation 241, a submodule upper insulation 242, and a submodule lower insulation 243. However, these insulations may be integrally formed. The outer periphery of the submodule thermal insulation 240 is covered by a frame member (not shown). The submodule peripheral insulation 241 is an insulation material that covers the periphery of a group or cluster of multiple electrolysis cartridges 220. A gap is provided between the submodule peripheral insulation 241 and the electrolysis cartridges 220. Note that the submodule peripheral insulation 241 does not cover the periphery of each individual electrolysis cartridge 220. The submodule upper insulation 242 is an insulation material that covers the upper part of the group or cluster of multiple electrolysis cartridges 220. For example, as shown in FIG. 12 (not in the first embodiment), the submodule lower insulation 243 is an insulation material that covers the lower part of the group or cluster of multiple electrolysis cartridges 220. 2 , the electrolysis module 200 of this embodiment does not include the submodule lower heat insulating part 243. This is because air supplied from the air supply primary line L10 is taken from the outside to the inside (inside) of the submodule heat insulating material 240 and then taken into the reaction chamber 224 via the supply flow path 223c1 provided in the cartridge lower heat insulating part 223c of the electrolysis cartridge 220.

[0038] 2 illustrates an example in which the entire submodule lower insulation 243 is omitted in order to draw air from the outside into the interior of the submodule insulation 240 that collectively surrounds the multiple electrolytic cartridges 220. However, at least a structure for drawing air from the outside into the interior of the submodule insulation 240 (hereinafter referred to as a "heat transfer gas intake section") may be present in any part of the submodule insulation 240. For example, the submodule lower insulation 243 may be partially omitted, or part or all of the submodule peripheral insulation 241 may be omitted, or part or all of the submodule upper insulation 242 may be omitted, or a combination thereof may be used. Note that a structure for drawing air from the outside into the interior is also provided in the frame member that covers the submodule insulation 240. Naturally, the position of the structure for drawing air provided in the frame member corresponds to the position of the heat transfer gas intake section of the submodule insulation 240.

[0039] By providing the sub-module insulation material 240, heat from the cell stack 230 can be blocked. Note that heat from the cell stack 230 is also blocked by the cartridge insulation material 223. However, if the cartridge insulation material 223 alone is used to insulate the heat from the cell stack 230, which can reach approximately 700°C to 1000°C, the cartridge insulation material 223 would have to be large. Furthermore, if the cartridge insulation material 223 were to be large, the electrolysis cartridge 220 would also have to be large. Therefore, the multiple electrolysis cartridges 220, each insulated by the cartridge insulation material 223, are collectively covered and insulated by the sub-module insulation material 240, thereby providing step-by-step and efficient insulation of heat from the cell stack 230.

[0040] The main supply pipe 251 is a pipe that connects the inside and outside of the pressure vessel 210. The end of the main supply pipe 251 located outside the pressure vessel 210 is connected to the air supply primary line L10. Furthermore, the end (exhaust port) of the main supply pipe 251 located inside the pressure vessel 210 is open inside the pressure vessel 210. As a result, air that has been cooled to approximately 200°C to 300°C in the heat exchanger L11 is supplied to the inside of the pressure vessel 210 via the air supply primary line L10. The main supply pipe 251 and the air supply primary line L10 may be configured as an integral unit or as separate units. In either case, the main supply pipe 251 can be considered to be part of the air supply primary line L10.

[0041] The air supplied to the interior of the pressure vessel 210 flows inside the pressure vessel 210. At this time, the interior of the pressure vessel 210 functions as a flow path. The air supplied to the interior of the pressure vessel 210 flows inside the pressure vessel 210, thereby lowering the atmospheric temperature inside the pressure vessel 210. After that, the air that has cooled the pressure vessel 210 is taken into the submodule insulation material 240 via the heat transfer gas intake section, and then taken into the reaction chamber 224 via the supply flow path 223c1.

[0042] The main discharge pipe 252 is a pipe that connects each oxygen-enriched air discharge pipe 222d of each electrolytic cartridge 220 to the outside of the pressure vessel 210. The end of the main discharge pipe 252 located outside the pressure vessel 210 is connected to the oxygen-enriched air discharge line L50. As a result, the oxygen-enriched air discharged from each electrolytic cartridge 220 is supplied to the turbine 122 via the oxygen-enriched air discharge line L50. The main discharge pipe 252 and the oxygen-enriched air discharge line L50 may be configured as an integrated unit or as separate units. In either case, the main discharge pipe 252 can be considered to be part of the oxygen-enriched air discharge line L50.

[0043] <Regarding Recirculation Lines> As shown in FIG. 1, the steam electrolysis system 10 includes a first recirculation line L71 and / or a second recirculation line L72.

[0044] The first recirculation line L71 connects the heat exchanger L41 of the hydrogen discharge line L40 to the portion of the water / steam supply line L30 downstream of the heat exchangers L11, L41, and L51, and is a line that guides the water vapor flowing through the hydrogen discharge line L40 to the water / steam supply line L30.

[0045] The second recirculation line L72 connects a portion of the hydrogen discharge line L40 downstream of the heat exchanger L41 to a portion of the water / steam supply line L30 upstream of the heat exchangers L11, L41, and L51, and guides water (condensed water vapor) flowing through the hydrogen discharge line L40 to the water / steam supply line L30. <Regarding control of flow rate and temperature> The steam electrolysis system 10 includes a first bypass line L81 and / or a second bypass line L82, and a controller 160.

[0046] The first bypass line L81 connects a portion of the air supply primary line L10 upstream of the heat exchanger L11 with a portion of the oxygen-enriched air discharge line L50 upstream of the heat exchanger L51, and is a line that guides air flowing through the air supply primary line L10 to the oxygen-enriched air discharge line L50. A valve 151 is provided on the first bypass line L81. A flow meter 171 is also provided on a portion of the air supply primary line L10 downstream of the point where the first bypass line L81 is connected. The control unit 160 obtains the flow rate of air flowing through the air supply primary line L10 from the flow meter 171 and controls the aperture of the valve 151 so that an amount of air appropriate for cooling is supplied to the electrolysis module 200. For example, the aperture of the valve 151 can be adjusted to allow a portion of the air flowing through the air supply primary line L10 to flow into the oxygen-enriched air discharge line L50 so as to prevent an excessive amount of air from being supplied to the electrolysis module 200.

[0047] The second bypass line L82 connects a portion of the air supply primary line L10 upstream of the heat exchanger L11 with a portion of the air supply primary line L10 downstream of the heat exchanger L11, and is a line for mixing high-temperature air before heat exchange in the heat exchanger L11 with low-temperature air after heat exchange. The second bypass line L82 is provided with a valve 152. The electrolysis module 200 is also provided with a thermometer 181. The control unit 160 acquires the internal temperature of the pressure vessel 210 from the thermometer 181 and controls the aperture of the valve 152 so that the internal temperature of the pressure vessel 210 (i.e., the temperature of the air supplied to the electrolysis cartridge 220) is maintained at an appropriate temperature. For example, the aperture of the valve 151 can be adjusted to increase the temperature of the air flowing through the air supply primary line L10 (air after heat exchange) so that excessively low-temperature air is not supplied to the electrolysis cartridge 220.

[0048] <Another Example of the Electrolysis Module> In this embodiment, air supplied to the interior of the pressure vessel 210 via the primary air supply line L10 flows through the interior of the pressure vessel 210, thereby cooling the interior of the pressure vessel 210. In this case, from the perspective of efficiently cooling the pressure vessel 210, for example, the heat transfer gas intake portion of the submodule insulation 240 may be positioned on the opposite side of the electrolysis cartridge 220 from the outlet of the main supply pipe 251 (i.e., the outlet of the primary air supply line L10). An example of this will be described below.

[0049] 8 , the submodule upper insulation 242 and the submodule lower insulation 243 of the submodule insulation 240 may be omitted, and the submodule insulation 240 may be formed with a submodule peripheral insulation 241, so that air discharged from the outlet of the main supply pipe 251 flows up to the upper part. However, if the submodule lower insulation 243 is omitted, the air discharged from the outlet of the main supply pipe 251 will immediately be taken into the electrolysis cartridge 220. Therefore, by providing the electrolysis module 200 with a blocking member (surrounding member) 261 that collectively blocks the lower parts of the multiple electrolysis cartridges 220, a heat transfer gas intake part is formed that ensures that air discharged from the outlet of the main supply pipe 251 (air supplied to the lower part of the pressure vessel 210) flows up to the upper part of the pressure vessel 210. A heat transfer gas intake section is formed by using the sub-module insulation 240 and the closing member 261 as surrounding members for the multiple electrolysis cartridges 220 and providing a surface (a surface for taking in the heat transfer gas) through which air can easily flow on one side. This allows the air discharged from the outlet of the main supply pipe 251 to easily circulate throughout the pressure vessel 210 before being taken into the heat transfer gas intake section of the sub-module insulation 240, resulting in a structure that makes it easy to cool the interior of the pressure vessel 210. Furthermore, because air flows around the electrolysis cartridges 220 in the height direction inside the sub-module insulation 240, a structure that makes it easy to cool the electrolysis cartridges 220 can be achieved.

[0050] 9 , the main supply pipe 251 may be located above the submodule, and the submodule lower insulation 243 may be omitted from the submodule insulation 240, so that the submodule insulation 240 is formed of the submodule upper insulation 242 and the submodule peripheral insulation 241. A heat transfer gas intake may be formed so that air discharged from the outlet of the main supply pipe 251 (air supplied to the upper part of the interior of the pressure vessel 210) flows around to the lower part of the interior of the pressure vessel 210. This makes it easier for the air discharged from the outlet of the main supply pipe 251 to circulate throughout the entire pressure vessel 210 before being taken into the heat transfer gas intake of the submodule insulation 240, resulting in a structure that makes it easier to cool the interior of the pressure vessel 210.

[0051] The present embodiment has the following advantages. Air whose temperature has been reduced by heat exchange with the feedwater is supplied to the pressure vessel 210, thereby reducing the atmospheric temperature inside the pressure vessel 210. This allows the use of relatively inexpensive materials that do not have high heat resistance as materials for the structural members housed inside the pressure vessel 210 (e.g., the members constituting the electrolysis cartridge 220), thereby achieving cost reduction. This also serves as a countermeasure to the phenomenon of an increase in the atmospheric temperature inside the pressure vessel 210 due to the increase in the overall pressure of the steam electrolysis system 10 including the electrolysis module 200. Furthermore, because the feedwater can be heated by heat exchange with the air, the thermal efficiency of the entire steam electrolysis system 10 can be improved.

[0052] Furthermore, since the air supplied to the pressure vessel 210 and used to cool the interior of the pressure vessel 210 is supplied to the electrolytic cartridge 220 without being removed from the pressure vessel 210, air can be supplied to the electrolytic cartridge 220 with a simple structure.

[0053] Furthermore, by mixing the air that has exchanged heat with the feed water with the air that has not exchanged heat with the feed water, the temperature of the air that has exchanged heat can be adjusted to appropriately control the temperature of the air supplied to the electrolysis module 200, thereby controlling the temperature inside the pressure vessel 210 and the temperature of the air supplied to the electrolysis cartridge 220.

[0054] Furthermore, since the heat transfer gas intake section of the submodule insulation material 240 is located on the opposite side of the electrolytic cartridge 220 from the outlet of the main supply pipe 251 (i.e., the outlet of the primary air supply line L10), the air discharged from the outlet can easily circulate throughout the pressure vessel 210 before being taken in by the heat transfer gas intake section, making it possible to create a structure in which the inside of the pressure vessel 210 can be easily cooled.

[0055] Second Embodiment The steam electrolysis system 10 according to this embodiment is the same as the steam electrolysis system 10 according to the first embodiment except for the inclusion of a return line L60. Therefore, the same components as those in the steam electrolysis system 10 according to the first embodiment are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0056] As shown in FIG. 10, the steam electrolysis system 10 includes a return line L60.

[0057] The return line L60 connects the interior of the pressure vessel 210 with a portion of the oxygen-enriched air discharge line L50 upstream of the heat exchanger L51, and is a line that guides the air inside the pressure vessel 210 to the oxygen-enriched air discharge line L50. By providing the return line L60, a portion of the air supplied to the interior of the pressure vessel 210 via the primary air supply line L10 can be extracted from the pressure vessel 210, thereby preventing an excessive amount of air from being supplied to the electrolysis cartridge 220 given the operating conditions. In other words, a portion of the air supplied via the primary air supply line L10 can be supplied to the electrolysis cartridge 220, and the remaining air (excess air) can be extracted from the pressure vessel 210.

[0058] The return line L60 is provided with a valve 153. The return line L60 is also provided with a flow meter 172. The control unit 160 may control the opening of the valve 153 so that the amount of air supplied to the electrolytic cartridge 220 is appropriate based on the amount of air appropriate for the operating conditions, the flow rate acquired from the flow meter 171, and the flow rate acquired from the flow meter 172. It is assumed that the amount of air appropriate for the operating conditions is known in advance.

[0059] A fixed throttle may be provided in the return line L60 instead of the valve 153. In this embodiment, the thermometer 181 used to control the valve 152 provided in the second bypass line L82 is provided in a portion of the air supply primary line L10 downstream of the heat exchanger L11. However, similar to the first embodiment, the thermometer 181 may also be provided in the electrolysis module 200.

[0060] This embodiment has the following advantages: A portion of the air that has been supplied to the pressure vessel 210 and used to cool the interior of the pressure vessel 210 is supplied to the electrolysis cartridge 220, and the remainder of the air that has been supplied to the pressure vessel 210 and used to cool the interior of the pressure vessel 210 is extracted from the pressure vessel 210, thereby preventing an excessive amount of air from being supplied to the electrolysis cartridge 220 relative to the operating conditions.

[0061] Third Embodiment The steam electrolysis system 10 according to this embodiment differs from the steam electrolysis system 10 according to the first embodiment in that it includes the configuration of an electrolysis module 200 and a secondary air supply line L20, but is otherwise the same as the steam electrolysis system 10 according to the first embodiment. Therefore, the same components as those in the steam electrolysis system 10 according to the first embodiment are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0062] 11 , the steam electrolysis system 10 includes a secondary air supply line (heat transfer gas supply line) L20. The secondary air supply line L20 is a line that removes the air that has been supplied to the pressure vessel 210 of the electrolysis module 200 via the primary air supply line L10 and used to cool the pressure vessel 210 from the pressure vessel 210, and supplies the removed air to the electrolysis cartridges 220.

[0063] 12 , the electrolysis module 200 includes a primary supply main pipe 253, a primary discharge main pipe 254, a secondary supply main pipe 255, and a secondary discharge main pipe 256, instead of the main supply pipe 251 and the main discharge pipe 252 of the first embodiment. The submodule heat insulating material 240 is formed of a submodule peripheral heat insulating section 241, a submodule upper heat insulating section 242, and a submodule lower heat insulating section 243. The electrolysis cartridge 220 includes an air supply header 222 a and an air supply pipe 222 b (see FIG. 5 ).

[0064] The primary supply main pipe 253 is a pipe that connects the inside and outside of the pressure vessel 210. The end of the primary supply main pipe 253 located outside the pressure vessel 210 is connected to the air supply primary line L10. Furthermore, the end (exhaust port) of the primary supply main pipe 253 located inside the pressure vessel 210 is open inside the pressure vessel 210. As a result, air that has been cooled to approximately 200°C to 300°C in the heat exchanger L11 is supplied to the inside of the pressure vessel 210 via the air supply primary line L10. The primary supply main pipe 253 and the air supply primary line L10 may be configured as an integral unit or as separate units. In either case, the primary supply main pipe 253 can be considered to be part of the air supply primary line L10.

[0065] The primary discharge main pipe 254 is a pipe that connects the inside and outside of the pressure vessel 210. The end of the primary discharge main pipe 254 located outside the pressure vessel 210 is connected to one end of the air supply secondary line L20. The end of the primary discharge main pipe 254 located inside the pressure vessel 210 is open inside the pressure vessel 210. This allows air that has been supplied to the inside of the pressure vessel 210 and used to cool the pressure vessel 210 to be guided to the air supply secondary line L20. That is, air supplied to the inside of the pressure vessel 210 from the air supply primary line L10 via the primary supply main pipe 253 flows inside the pressure vessel 210 and is discharged to the air supply secondary line L20 via the primary discharge main pipe 254. At this time, the inside of the pressure vessel 210 functions as a flow path. The primary discharge main pipe 254 and the air supply secondary line L20 may be configured as an integral unit or as separate units. In either case, the primary discharge main 254 can be considered part of the air supply secondary line L20.

[0066] The secondary supply main pipe 255 is a pipe that connects each air supply pipe 222b of each electrolytic cartridge 220 to the outside of the pressure vessel 210. The end of the secondary supply main pipe 255 located outside the pressure vessel 210 is connected to the other end of the air supply secondary line L20. As a result, the air flowing through the air supply secondary line L20 (air after cooling the pressure vessel 210) is supplied to the electrolytic cartridge 220.

[0067] The secondary main discharge pipe 256 is a pipe that connects each oxygen-enriched air discharge pipe 222d of each electrolytic cartridge 220 to the outside of the pressure vessel 210. The end of the secondary main discharge pipe 256 located outside the pressure vessel 210 is connected to the oxygen-enriched air discharge line L50. As a result, the oxygen-enriched air discharged from each electrolytic cartridge 220 is supplied to the turbine 122 via the oxygen-enriched air discharge line L50.

[0068] As described above, in the steam electrolysis system 10 of this embodiment, the secondary air supply line L20 is used to extract air that has cooled the pressure vessel 210 from the pressure vessel 210, and the extracted air is supplied to the electrolysis cartridge 220.

[0069] 11 , the secondary air supply line L20 is provided with a flow meter 173 and a pressure applying means 191. The control unit 160 obtains the flow rate of air flowing through the secondary air supply line L20 from the flow meter 173 and controls the pressure applying means 191 so that an appropriate amount of air for the operating conditions is supplied to the electrolysis module 200. Examples of the pressure applying means 191 include a compressor and a pump.

[0070] In this embodiment, the thermometer 181 used to control the valve 152 provided in the second bypass line L82 is provided in a portion of the air supply primary line L10 downstream of the heat exchanger L11. However, similar to the first embodiment, the thermometer 181 may also be provided in the electrolysis module 200.

[0071] According to this embodiment, the following effects are achieved: The air that has been supplied to the pressure vessel 210 and cooled the interior of the pressure vessel 210 is extracted from the pressure vessel 210, the flow rate of the extracted air is adjusted by the pressure applying means 191, and the flow rate-adjusted air is supplied to the electrolysis cartridge 220, so that air at an appropriate flow rate can be supplied to the electrolysis cartridge 220.

[0072] Fourth embodiment The steam electrolysis system 10 according to this embodiment is the same as the steam electrolysis system 10 according to the third embodiment except for the configuration of the secondary air supply line L20. Therefore, the same components as those in the steam electrolysis system 10 according to the third embodiment are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0073] As shown in FIG. 13 , a heat exchanger L21 is provided in the secondary air supply line L20. The heat exchanger L21 serves as a heat source for heating the feedwater. That is, the air extracted from the pressure vessel 210 after cooling the pressure vessel 210 is cooled again in the heat exchanger L21 before being supplied to the electrolysis cartridge 220. The heat exchanger L21 is provided in parallel with the water / steam supply line L30 together with the other heat exchangers L11, L41, and L51, for example. However, each heat exchanger may be provided in series with the water / steam supply line L30. Alternatively, only some of the heat exchangers may be provided in parallel with the water / steam supply line L30, and the remaining heat exchangers may be provided in series.

[0074] The steam electrolysis system 10 includes a third bypass line L83. The third bypass line L83 connects a portion of the air supply secondary line L20 upstream of the heat exchanger L21 with a portion of the air supply secondary line L20 downstream of the heat exchanger L21, and is a line for mixing high-temperature air before heat exchange in the heat exchanger L21 with low-temperature air after heat exchange. A valve 154 is provided on the third bypass line L83. A thermometer 182 is also provided on the air supply secondary line L20 downstream of the heat exchanger L21. The control unit 160 obtains the temperature of the air flowing through the air supply secondary line L20 from the thermometer 182 and controls the aperture of the valve 154 so that the temperature of the air supplied to the electrolysis cartridge 220 is appropriate. For example, the aperture of the valve 154 can be adjusted to increase the temperature of the air flowing through the air supply secondary line L20 (air after heat exchange) so as to prevent excessively low-temperature air from being supplied to the electrolysis cartridge 220.

[0075] In this embodiment, the thermometer 181 used to control the valve 152 provided in the second bypass line L82 is provided in a portion of the air supply primary line L10 downstream of the heat exchanger L11. However, similar to the first embodiment, the thermometer 181 may also be provided in the electrolysis module 200.

[0076] According to this embodiment, the following effects are achieved: The air that has been supplied to the pressure vessel 210 and used to cool the interior of the pressure vessel 210 is removed from the pressure vessel 210, the air removed from the pressure vessel 210 is again subjected to heat exchange with the feed water, and the air that has been heat exchanged again is supplied to the electrolysis cartridge 220. Therefore, the temperature of the air that has been increased by heat exchange with the pressure vessel 210 can be lowered by heat exchange with the feed water before being supplied to the electrolysis cartridge 220.

[0077] Fifth embodiment The steam electrolysis system 10 according to this embodiment differs from the steam electrolysis system 10 according to the fourth embodiment in the configuration of the air supply primary line L10, in that the system does not include the secondary air supply line L20, and in that the system includes a circulation line L90, but is otherwise the same. Therefore, the same components as those in the steam electrolysis system 10 according to the fourth embodiment are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0078] 14 , the circulation line (heat transfer gas supply line) L90 is a line for removing the heat transfer gas from the pressure vessel 210 after it has been supplied into the pressure vessel 210 of the electrolysis module 200 and cooled the pressure vessel 210, and for supplying the removed heat transfer gas back into the pressure vessel 210. An example of the heat transfer gas is an inert gas such as air.

[0079] The end of the primary supply main pipe 253 located outside the pressure vessel 210 is connected to one end of the circulation line L90. The end of the primary discharge main pipe 254 located outside the pressure vessel 210 is connected to the other end of the circulation line L90. That is, the circulation line L90, together with the internal space of the pressure vessel 210, which functions as a flow path, constitutes a system for circulating the heat transfer medium gas. Furthermore, the circulation line L90 is independent of the other lines L10, L30, L40, and L50. Therefore, the type of heat transfer medium gas flowing through the circulation line L90 does not depend on the type of fluid flowing through the other lines. The primary supply main pipe 253 and the circulation line L90 may be configured as an integrated unit or separate units. The primary discharge main pipe 254 and the circulation line L90 may be configured as an integrated unit or separate units. In either case, the primary supply main pipe 253 and / or the primary discharge main pipe 254 can be considered part of the circulation line L90.

[0080] The end of the secondary supply main pipe 255 located outside the pressure vessel 210 is connected to the primary air supply line L10. As a result, the air flowing through the primary air supply line L10 is supplied to the electrolytic cartridge 220.

[0081] The end of the secondary main discharge pipe 256 located outside the pressure vessel 210 is connected to the oxygen-enriched air discharge line L50. As a result, the oxygen-enriched air discharged from each electrolysis cartridge 220 is supplied to the turbine 122 via the oxygen-enriched air discharge line L50.

[0082] A heat exchanger L91 is provided in the circulation line L90. The heat exchanger L91 is used as a heat source for heating the feedwater. That is, the heat medium gas extracted from the pressure vessel 210 after cooling the pressure vessel 210 is cooled in the heat exchanger L91 and then supplied back into the pressure vessel 210. The heat exchanger L91 is provided in parallel with the water / steam supply line L30 together with the other heat exchangers L11, L41, and L51. However, each heat exchanger may be provided in series with the water / steam supply line L30. Alternatively, only some of the heat exchangers may be provided in parallel with the water / steam supply line L30, and the remaining heat exchangers may be provided in series.

[0083] The steam electrolysis system 10 includes a fourth bypass line L84. The fourth bypass line L84 connects a portion of the circulation line L90 upstream of the heat exchanger L91 with a portion of the circulation line L90 downstream of the heat exchanger L91, and is a line for mixing the high-temperature heat medium gas before heat exchange in the heat exchanger L91 with the low-temperature heat medium gas after heat exchange. A valve 155 is provided on the fourth bypass line L84. A pressure applying unit 191 is provided on the circulation line L90 downstream of the heat exchanger L91. The electrolysis module 200 is also provided with a thermometer 183. The control unit 160 obtains the temperature of the heat medium gas flowing through the circulation line L90 from the thermometer 183 and controls the pressure applying unit 191 so that an appropriate amount of heat medium gas is supplied to the electrolysis module 200 for the operating conditions. Examples of the pressure applying unit 191 include a compressor and a pump. The control unit 160 also obtains the temperature of the heat medium gas flowing through the circulation line L90 from the thermometer 183 and controls the aperture of the valve 155 so that the temperature of the heat medium gas supplied to the electrolysis module 200 is an appropriate temperature. For example, the control unit 160 can adjust the aperture of the valve 155 to increase the temperature of the heat medium gas (heat medium gas after heat exchange) flowing through the circulation line L90 so that an excessively low-temperature heat medium gas is not supplied to the electrolysis module 200.

[0084] As described above, in the steam electrolysis system 10 of this embodiment, the circulation line L90 is used to extract the heat transfer gas that has cooled the pressure vessel 210 from the pressure vessel 210 and to supply the extracted heat transfer gas back into the pressure vessel 210. Furthermore, the flow rate and temperature of the extracted heat transfer gas are adjusted before it is supplied back into the pressure vessel 210.

[0085] This embodiment has the following advantages: The system for cooling the interior of the pressure vessel 210 can be separated from the other lines. This simplifies the system structure. Furthermore, the type of heat transfer gas flowing through the circulation line L90 does not depend on the type of fluid flowing through the other lines.

[0086] The systems of the respective embodiments can also be applied to a system that performs CO co-electrolysis, which simultaneously performs electrolysis of water vapor and carbon dioxide, and a system that performs ammonia electrolysis, which simultaneously performs water vapor electrolysis and ammonia synthesis from nitrogen.

[0087] [Additional Notes] The electrolysis module cooling method and electrolysis system according to the present disclosure described above may be understood, for example, as follows: A cooling method for an electrolysis module according to a first aspect of the present disclosure is a method for cooling an electrolysis module (200), the method comprising: an electrolysis cell (232) including a hydrogen electrode (232 a), an oxygen electrode (232 b), and an electrolyte layer (232 c) disposed between the hydrogen electrode (232 a) and the oxygen electrode (232 b); at least one electrolysis cartridge (220) configured to generate hydrogen by electrolyzing water vapor generated from feedwater; and a container (210) accommodating the electrolysis cartridge (220), the method comprising: exchanging heat between a heat transfer gas and the feedwater to heat the feedwater; and supplying the heat-exchanged heat transfer gas to the container (210) to cool the interior of the container (210).

[0088] According to the cooling method for the electrolysis module (200) of this embodiment, a heat transfer gas is heat exchanged with the feedwater to heat the feedwater, and the heat-exchanged heat transfer gas is supplied to the container (210). Therefore, the heat transfer gas, whose temperature has been reduced by heat exchange with the feedwater, is supplied to the container (210), thereby lowering the ambient temperature inside the container (210). This allows lower-quality materials to be used for the structural members housed inside the container (210), thereby achieving cost reduction. This also serves as a countermeasure against the phenomenon of an increase in the ambient temperature inside the container (210) due to the overall high pressure of the system including the electrolysis module (200). Furthermore, since the feedwater can be heated by heat exchange with the heat transfer gas, the thermal efficiency of the entire system can be improved.

[0089] In a cooling method for an electrolysis module according to a second aspect of the present disclosure, in the first aspect, the heat transfer gas that has been supplied to the container (210) and cooled the inside of the container (210) is supplied to the electrolysis cartridge (220).

[0090] According to the cooling method for the electrolysis module (200) of this aspect, the heat transfer gas that has been supplied to the container (210) and cooled the inside of the container (210) is supplied to the electrolysis cartridge (220), so that the temperature of the electrolysis cartridge (220) can be maintained at an appropriate temperature by the heat transfer gas.

[0091] In a cooling method for an electrolysis module according to a third aspect of the present disclosure, in the second aspect, the heat transfer gas that has been supplied to the container (210) and cooled the inside of the container (210) is supplied to the electrolysis cartridge (220) without being removed from the container (210).

[0092] According to the cooling method for the electrolysis module (200) of this aspect, the heat transfer gas that has been supplied to the container (210) and has cooled the inside of the container (210) is supplied to the electrolysis cartridge (220) without being removed from the container (210), and therefore the heat transfer gas can be supplied to the electrolysis cartridge (220) with a simple structure.

[0093] In the method for cooling an electrolysis module according to a fourth aspect of the present disclosure, in the second aspect, a portion of the heat transfer gas that has been supplied to the container (210) and cooled the interior of the container (210) is supplied to the electrolysis cartridge (220), and the remainder of the heat transfer gas that has been supplied to the container (210) and cooled the interior of the container (210) is removed from the container (210).

[0094] According to the cooling method for the electrolysis module (200) of this aspect, a portion of the heat transfer gas that has been supplied to the container (210) and cooled the interior of the container (210) is supplied to the electrolysis cartridge (220), and the remainder of the heat transfer gas that has been supplied to the container (210) and cooled the interior of the container (210) is removed from the container (210). This makes it possible to prevent an excessive amount of heat transfer gas from being supplied to the electrolysis cartridge (220) for the operating conditions.

[0095] In the method for cooling an electrolysis module according to a fifth aspect of the present disclosure, in the second aspect, the heat transfer gas that has been supplied to the container (210) and has cooled the inside of the container (210) is removed from the container (210), a flow rate of the removed heat transfer gas is adjusted, and the heat transfer gas with the adjusted flow rate is supplied to the electrolysis cartridge (220).

[0096] According to the cooling method for the electrolysis module (200) of this aspect, the heat transfer gas that has been supplied to the container (210) and has cooled the inside of the container (210) is removed from the container (210), the flow rate of the removed heat transfer gas is adjusted, and the heat transfer gas with the adjusted flow rate is supplied to the electrolysis cartridge (220). As a result, the heat transfer gas can be supplied to the electrolysis cartridge (220) at an appropriate flow rate.

[0097] In a cooling method for an electrolysis module according to a sixth aspect of the present disclosure, in the second aspect, the heat transfer gas that has been supplied to the container (210) and cooled the inside of the container (210) is removed from the container (210), the heat transfer gas removed from the container (210) is again subjected to heat exchange with the feed water, and the heat transfer gas that has been heat exchanged again is supplied to the electrolysis cartridge (220).

[0098] According to the cooling method for the electrolysis module (200) of this aspect, the heat transfer gas that has been supplied to the container (210) and cooled the inside of the container (210) is removed from the container (210), the heat transfer gas removed from the container (210) is again subjected to heat exchange with the feed water, and the heat transfer gas that has been heat exchanged again is supplied to the electrolysis cartridge (220). Therefore, the temperature of the heat transfer gas that has increased due to heat exchange with the container (210) can be lowered by heat exchange with the feed water before being supplied to the electrolysis cartridge (220).

[0099] In a cooling method for an electrolysis module according to a seventh aspect of the present disclosure, in the first aspect, the heat transfer gas that has been supplied to the container (210) and cooled the inside of the container (210) is removed from the container (210), the heat transfer gas removed from the container (210) is again subjected to heat exchange with the feedwater, and the heat transfer gas that has been heat exchanged again is again supplied into the container (210).

[0100] According to the cooling method for the electrolysis module (200) of this aspect, the heat transfer gas supplied to the container (210) and having cooled the interior of the container (210) is removed from the container (210), the removed heat transfer gas is again subjected to heat exchange with the feedwater, and the heat transfer gas that has been heat exchanged again is again supplied to the inside of the container (210), so that the system for cooling the interior of the container (210) can be made independent, thereby simplifying the structure of the system.

[0101] According to an eighth aspect of the present disclosure, in the cooling method for an electrolysis module of any one of the first to seventh aspects, the heat transfer gas after heat exchange with the feed water is mixed with the heat transfer gas before heat exchange with the feed water.

[0102] According to the cooling method for the electrolysis module (200) of this aspect, the heat transfer gas after heat exchange with the feed water is mixed with the heat transfer gas before heat exchange with the feed water. Therefore, the temperature of the air after heat exchange can be adjusted to appropriately control the temperature of the air supplied to the electrolysis module (200), and the temperature inside the container (210) and the temperature of the air supplied to the electrolysis cartridge (220) can be controlled.

[0103] A ninth aspect of the present disclosure relates to a cooling method for an electrolysis module according to the eighth aspect, wherein a flow rate of the heat transfer gas to be mixed is adjusted in accordance with at least one of a temperature inside the container (210) and a temperature of the heat transfer gas after heat exchange.

[0104] According to the cooling method for the electrolysis module (200) of this aspect, the flow rate of the heat transfer gas to be mixed is adjusted in accordance with at least one of the temperature inside the container (210) and the temperature of the heat transfer gas after heat exchange. Therefore, by feeding back the temperature inside the container (210) and the temperature of the heat transfer gas after heat exchange, the temperature of the heat transfer gas can be maintained at an appropriate temperature.

[0105] An electrolysis system according to a tenth aspect of the present disclosure includes an electrolysis module (200), heat exchangers (L11, L21, L91), and heat transfer medium gas supply lines (L10, L20, L90), wherein the electrolysis module (200) has at least one electrolysis cartridge (220) and a container (210), and the electrolysis cartridge (220) contains an electrolysis chamber having a hydrogen electrode (232a), an oxygen electrode (232b), and an electrolyte layer (232c) disposed between the hydrogen electrode (232a) and the oxygen electrode (232b). The electrolysis system includes a cell (232) and generates hydrogen by electrolyzing water vapor generated from feedwater, the container (210) accommodates the electrolysis cartridge (220), the heat transfer gas supply line (L10, L20, L90) is a line through which a heat transfer gas flows, and is configured to supply the heat transfer gas as a heat source for heating the feedwater to the heat exchanger (L11, L21, L91), and to supply the heat transfer gas that has been heat exchanged in the heat exchanger (L11, L21, L91) to the container (210).

[0106] In the electrolysis system (10) according to this aspect, the heat transfer gas supply lines (L10, L20, L90) are lines through which the heat transfer gas flows. The heat transfer gas, which serves as a heat source for heating the feedwater, is supplied to the heat exchangers (L11, L21, L91), and the heat transfer gas that has undergone heat exchange in the heat exchangers (L11, L21, L91) is supplied to the container (210). Therefore, the heat transfer gas whose temperature has been reduced by heat exchange with the feedwater is supplied to the container (210), thereby reducing the ambient temperature inside the container (210). This allows the container (210) to be made of a low-quality material, thereby achieving cost reduction. This also serves as a countermeasure against the phenomenon of an increase in the ambient temperature inside the container (210) due to the increase in pressure of the entire system including the electrolysis module (200). Furthermore, the heat exchange with the heat transfer gas allows the feedwater to be heated, thereby improving the thermal efficiency of the entire system.

[0107] An electrolysis system according to an eleventh aspect of the present disclosure is the tenth aspect, wherein the heat transfer medium gas supply line (L10, L20, L90) has an outlet through which the supplied heat transfer medium gas is discharged, the outlet being located inside the container (210), and the electrolysis module (200) has an enclosing member (240, 261) that covers the plurality of electrolysis cartridges (220), the enclosing member (240, 261) having a heat transfer medium gas intake portion that takes the heat transfer medium gas inside, and the electrolysis module (200) is accommodated in the container (210) together with the electrolysis cartridges (220).

[0108] In the electrolysis system (10) according to this aspect, the heat transfer medium gas supply lines (L10, L20, L90) have an outlet through which the supplied heat transfer medium gas is discharged, and the outlet is located inside the container (210). The electrolysis module (200) has an enclosure (240, 261) that covers the multiple electrolysis cartridges (220). The enclosure (240, 261) has a heat transfer medium gas intake section that takes in the heat transfer medium gas inside, and is housed in the container (210) together with the electrolysis cartridges (220). Therefore, the heat transfer medium gas discharged into the container (210) can be directly taken into the electrolysis cartridges (220) via the heat transfer medium gas intake section. This allows the heat transfer medium gas to be supplied to the electrolysis cartridges (220) with a simple structure.

[0109] According to a twelfth aspect of the present disclosure, in the electrolysis system of the eleventh aspect, the heat transfer gas intake is located on the opposite side of the electrolysis cartridge (220) from the discharge port.

[0110] In the electrolysis system (10) according to this aspect, the heat transfer gas intake section is located on the opposite side of the electrolysis cartridge (220) from the discharge port. This allows the heat transfer gas discharged from the discharge port to easily circulate throughout the container (210) before being taken into the heat transfer gas intake section, thereby enabling a structure in which the interior of the container (210) is easily cooled.

[0111] 10 Steam electrolysis system (electrolysis system) 120 Compression device 121 Compressor 122 Turbine 123 Electric motor 130 Water supply device 140 Power supply device 151, 152, 153, 154, 155 Valve 160 Control unit 171, 172, 173 Flow meter 181, 182, 183 Thermometer 191 Pressure applying means 200 Electrolysis module 210 Pressure vessel 220 Electrolysis cartridge 221a Steam supply header 221b Steam supply pipe 221c Hydrogen discharge header 221d Hydrogen discharge pipe 222a Air supply header 222b Air supply pipe 222c Oxygen-enriched air discharge header 222d Oxygen-enriched air discharge pipe 223 Cartridge insulation 223a Cartridge surrounding insulation part 223b Cartridge upper insulation part 223b1 Discharge flow path 223c Cartridge lower insulation part 223c1 Supply flow path 224 Electrolysis chamber (reaction chamber) 230 Cell stack 231 Substrate tube 232 Electrolysis cell 232a Hydrogen electrode 232b Oxygen electrode 232c Electrolyte layer 233 Interconnector 234 Lead film 240 Submodule insulation material (enclosure member) 241 Submodule peripheral insulation part 242 Submodule upper insulation part 243 Submodule lower insulation part 251 Supply main pipe 252 Discharge main pipe 253 Primary supply main pipe 254 Primary discharge main pipe 255 Secondary supply main pipe 256 Secondary discharge main pipe 261 Blocking member (enclosure member) L10 Air supply primary line (heat medium gas supply line) L11 Heat exchanger L20 Secondary air supply line (heat medium gas supply line) L21 Heat exchanger L30 Water / steam supply line L40 Hydrogen discharge line L41 Heat exchanger L50 Oxygen-enriched air discharge line L51 Heat exchanger L60 Return line L71 First recirculation line L72 Second recirculation line L81 First bypass line L82 Second bypass line L83 Third bypass line L84 Fourth bypass line L90 Circulation line (heat medium gas supply line) L91 Heat exchanger

Claims

1. A cooling method for an electrolysis module, comprising: at least one electrolysis cartridge that includes an electrolysis cell having a hydrogen electrode, an oxygen electrode, and an electrolyte layer disposed between the hydrogen electrode and the oxygen electrode, and that generates hydrogen by electrolyzing water vapor generated from feed water; and a container that houses the electrolysis cartridge, the cooling method comprising: exchanging heat between a heat transfer gas and feed water to heat the feed water; and supplying the heat-exchanged heat transfer gas to the container to cool the inside of the container.

2. The method for cooling an electrolysis module according to claim 1, wherein the heat transfer gas that has been supplied to the container and cooled the inside of the container is supplied to the electrolysis cartridge.

3. The method for cooling an electrolysis module according to claim 2, wherein the heat transfer gas that has been supplied to the container and cooled the inside of the container is supplied to the electrolysis cartridge without being taken out of the container.

4. The method for cooling an electrolysis module according to claim 2, further comprising: supplying a portion of the heat transfer gas that has been supplied to the container and cooled the interior of the container to the electrolysis cartridge; and removing the remainder of the heat transfer gas that has been supplied to the container and cooled the interior of the container from the container.

5. The cooling method for an electrolysis module according to claim 2, further comprising the steps of: removing the heat transfer gas from the container after it has been supplied to the container and cooled the interior of the container; adjusting the flow rate of the removed heat transfer gas; and supplying the heat transfer gas with the adjusted flow rate to the electrolysis cartridge.

6. The method for cooling an electrolysis module according to claim 2, further comprising the steps of: removing the heat transfer gas that has been supplied to the container and cooled the inside of the container from the container; subjecting the heat transfer gas that has been removed from the container to heat exchange again with the feed water; and supplying the heat transfer gas that has been heat exchanged again to the electrolysis cartridge.

7. The method for cooling an electrolysis module according to claim 1, further comprising the steps of: removing the heat transfer gas from the container after it has been supplied to the container and cooled the interior of the container; subjecting the heat transfer gas removed from the container to heat exchange again with the feed water; and supplying the heat transfer gas after heat exchange again into the container.

8. The method for cooling an electrolysis module according to any one of claims 1 to 7, wherein the heat transfer gas after heat exchange with the feed water is mixed with the heat transfer gas before heat exchange with the feed water.

9. The method for cooling an electrolysis module according to claim 8, wherein the flow rate of the heat transfer gas to be mixed is adjusted according to at least one of the temperature inside the container and the temperature of the heat transfer gas after heat exchange.

10. An electrolysis system comprising: an electrolysis module; a heat exchanger; and a heat transfer gas supply line, wherein the electrolysis module has at least one electrolysis cartridge and a container, wherein the electrolysis cartridge comprises an electrolysis cell having a hydrogen electrode, an oxygen electrode, and an electrolyte layer disposed between the hydrogen electrode and the oxygen electrode, and generates hydrogen by electrolyzing water vapor generated from feed water, wherein the container accommodates the electrolysis cartridge, and the heat transfer gas supply line is a line through which a heat transfer gas flows, and is configured to supply the heat transfer gas as a heat source for heating the feed water to the heat exchanger, and to supply the heat transfer gas that has been heat exchanged in the heat exchanger to the container.

11. The electrolysis system according to claim 10, wherein the heat transfer gas supply line has an outlet through which the supplied heat transfer gas is discharged, the outlet being located inside the container, and the electrolysis module has an enclosure member that covers the plurality of electrolysis cartridges, the enclosure member having a heat transfer gas intake section that takes in the heat transfer gas inside, and the enclosure member is housed in the container together with the electrolysis cartridges.

12. The electrolysis system according to claim 11, wherein the heat transfer gas intake section is located on the opposite side of the electrolysis cartridge from the outlet.

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