Electrolysis system and method of operating the same

Abstract

The present invention provides an electrolysis system and an operation method thereof. An inner shell (28) of an electrolysis system (10) is used to accommodate an electrolytic stack (12). An intermediate shell (30) surrounds the inner shell (28) from the outside. An outer shell (32) surrounds the intermediate shell (30) from the outside. The operation method of the electrolysis system (10) includes a vacuum process, a heat storage process, and a start electrolysis process. In the vacuum process, air in a vacuum space (36) arranged between the intermediate shell (30) and the outer shell (32) is discharged. In the heat storage process, a heating fluid is supplied to a heat storage space (34) arranged between the inner shell (28) and the intermediate shell (30). Accordingly, the temperature of the heat storage space can be adjusted. Accordingly, the temperature of the electrolytic stack can be easily controlled.

Description

Technical Field

[0001] The invention relates to an electrolysis system and an operation method thereof. Background Art

[0002] Solid oxide electrolysis cell (SOEC) electrolyzes CO2 gas and water vapor to produce synthesis gas (mixed gas of CO gas and hydrogen). The use of SOEC as one of the P2G (Power to Gas) technology and CO2 reduction technology is being studied. This SOEC is stacked in multiple layers and used as an electrolytic stack. The electrolytic stack needs to work at a high temperature of 600℃ to 900℃. Therefore, the electrolytic stack is housed in a shell for thermal insulation.

[0003] Regarding the heat insulation structure of the shell that houses the electrolytic stack, for example, Japanese Patent Publication No. 2004-139960 discloses a shell that houses a solid oxide fuel cell (SOFC). The shell has a vacuum insulation layer, so that the heat of the SOFC can be efficiently used to preheat the gas. Summary of the invention

[0004] However, in the SOFC system described in Japanese Patent Application Laid-Open No. 2004-139960, since the vacuum insulation layer needs to be sealed in the manufacturing stage, there is a problem that the vacuum degree decreases when a slight amount of gas leakage continues.

[0005] The purpose of the present invention is to solve the above technical problems.

[0006] A technical solution of the present invention is: an electrolysis system, which has an electrolysis stack formed by stacking a plurality of solid oxide-shaped electrolysis cells, characterized in that it has an inner shell, an intermediate shell and an outer shell, wherein the inner shell is used to accommodate the electrolysis stack; the intermediate shell surrounds the inner shell from the outside; the outer shell surrounds the intermediate shell from the outside, a heat storage space is arranged between the inner shell and the intermediate shell, a vacuum space is arranged between the intermediate shell and the outer shell, a fluid supply flow path for supplying a heating fluid to the heat storage space is provided in the intermediate shell, and an air outlet flow path for discharging air in the vacuum space to the outside is provided in the outer shell.

[0007] Another technical solution of the present invention is: an operating method of an electrolysis system, the electrolysis system has an electrolysis stack formed by stacking a plurality of solid oxide-shaped electrolysis cells, the operating method of the electrolysis system is characterized in that the electrolysis system has an inner shell, an intermediate shell and an outer shell, wherein the inner shell is used to accommodate the electrolysis stack; the intermediate shell surrounds the inner shell from the outside; the outer shell surrounds the intermediate shell from the outside, the operating method of the electrolysis system includes a vacuum process, a heat storage process and a start electrolysis process, wherein in the vacuum process, air in a vacuum space arranged between the intermediate shell and the outer shell is discharged; in the heat storage process, a heating fluid is supplied to the heat storage space arranged between the inner shell and the intermediate shell; in the start electrolysis process, electrolysis by the electrolysis stack is started after the vacuum process and the heat storage process.

[0008] According to the present invention, the vacuum degree of the vacuum space can be adjusted by discharging the air in the vacuum space from the air outlet passage to the outside. In addition, the temperature of the heat storage space can be adjusted by supplying a heating fluid from the fluid supply passage to the heat storage space. Thus, the temperature management of the electrolytic stack can be easily performed.

[0009] The above-mentioned objects, features and advantages will be easily understood through the following description of the embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic structural diagram of an electrolysis system involved in one embodiment of the present invention.

[0011] Figure 2 It is along Figure 1 Cross-sectional view of II-II.

[0012] Figure 3 Yes Description Figure 1 Flow chart of the operating method of the electrolysis system.

[0013] Figure 4 Yes Description Figure 3 Flow chart of the heat storage process. DETAILED DESCRIPTION

[0014] like Figure 1 As shown, the electrolysis system 10 according to one embodiment of the present invention includes an electrolytic stack 12 , a housing member 14 , a reaction fluid supply unit 16 , a synthesis gas outlet 18 , a vacuum generator 20 , a temperature regulator 22 , and a controller 24 .

[0015] The electrolytic stack 12 has a plurality of electrolytic cells 26. The plurality of electrolytic cells 26 are stacked on each other. The electrolytic cell 26 is a solid oxide electrolytic cell (SOEC). The electrolytic cell 26 electrolyzes CO2 gas (carbon dioxide gas) and water vapor to produce a synthesis gas containing CO gas (carbon monoxide gas) and hydrogen. The electrolytic cell 26 operates at a relatively high temperature (for example, above 600°C and below 900°C). Although detailed illustrations are omitted, the electrolytic cell 26 has an electrolyte (solid oxide electrolyte), a cathode electrode, and an anode electrode. The cathode electrode is disposed on one surface of the electrolyte. The anode electrode is disposed on the other side of the electrolyte. The electrolytic stack 12 is electrically connected to an electrolysis power source not shown.

[0016] The case member 14 includes an inner case 28, an intermediate case 30, and an outer case 32. The inner case 28 accommodates the electrolytic stack 12. The intermediate case 30 covers the inner case 28 from the outside. The outer case 32 covers the intermediate case 30 from the outside. That is, the case member 14 has a triple structure in which the electrolytic stack 12 is covered by three cases.

[0017] The inner housing 28, the intermediate housing 30, and the outer housing 32 are each a square box (hexahedron) (see Figure 1 and Figure 2 ). A heat storage space 34 is arranged between the inner shell 28 and the intermediate shell 30. The heat storage space 34 covers the entire inner shell 28 from the outside. A vacuum space 36 is arranged between the intermediate shell 30 and the outer shell 32. The vacuum space 36 covers the entire intermediate shell 30 from the outside. The shapes and sizes of the inner shell 28, the intermediate shell 30, and the outer shell 32 can be changed as appropriate.

[0018] The inner housing 28 includes a first inner wall surface 28a facing the direction of arrow X1, a second inner wall surface 28b facing the direction of arrow X2, a third inner wall surface 28c facing the direction of arrow Y1, and a fourth inner wall surface 28d facing the direction of arrow Y2. The intermediate housing 30 includes a first intermediate wall surface 30a facing the direction of arrow X1, a second intermediate wall surface 30b facing the direction of arrow X2, a third intermediate wall surface 30c facing the direction of arrow Y1, and a fourth intermediate wall surface 30d facing the direction of arrow Y2. The outer housing 32 includes a first outer wall surface 32a facing the direction of arrow X1, a second outer wall surface 32b facing the direction of arrow X2, a third outer wall surface 32c facing the direction of arrow Y1, and a fourth outer wall surface 32d facing the direction of arrow Y2.

[0019] The housing member 14 includes a fluid supply pipe 38, a fluid discharge pipe 40, and an air outlet pipe 42. The fluid supply pipe 38 supplies a heating fluid to the heat storage space 34. The fluid discharge pipe 40 discharges the fluid in the heat storage space 34 to the outside. The air outlet pipe 42 discharges the air in the vacuum space 36 to the outside. The fluid supply pipe 38, the fluid discharge pipe 40, and the air outlet pipe 42 extend in a straight line.

[0020] One end of the fluid supply pipe 38 is airtightly joined to the first intermediate wall 30a. The fluid supply flow path 38a, which is the inner hole of the fluid supply pipe 38, is connected to the heat storage space 34. One end of the fluid supply pipe 38 is located approximately at the center of the first intermediate wall 30a (see Figure 1 and Figure 2 A fluid supply door 44 (opening and closing portion) for opening or closing the fluid supply flow path 38 a is attached to the other end of the fluid supply tube portion 38 .

[0021] One end of the fluid discharge pipe portion 40 is airtightly joined to the fourth intermediate wall surface 30d. The fluid discharge flow path 40a, which is the inner hole of the fluid discharge pipe portion 40, is connected to the heat storage space 34. One end of the fluid discharge pipe portion 40 is located at a position offset from the center of the fourth intermediate wall surface 30d in the arrow X direction to the side opposite to the fluid supply flow path 38a (the second intermediate wall surface 30b side). The other end of the fluid discharge pipe portion 40 is airtightly joined to the fourth outer wall surface 32d. A fluid discharge door 46 (opening and closing portion) for opening or closing the fluid discharge flow path 40a is installed at the other end of the fluid discharge pipe portion 40.

[0022] One end of the air outlet pipe 42 is airtightly joined to the first outer wall surface 32a. The air outlet flow path 43, which is the inner hole of the air outlet pipe 42, is connected to the vacuum space 36. The air outlet pipe 42 covers the fluid supply pipe 38. In other words, the fluid supply pipe 38 (fluid supply flow path 38a) is located in the air outlet flow path 43.

[0023] Specifically, the air outlet flow path 43 is cut off in the arrow Y direction by the fluid supply pipe 38. That is, the air outlet flow path 43 includes a first air outlet flow path 42a and a second air outlet flow path 42b. The first air outlet flow path 42a is located in the arrow Y1 direction of the fluid supply pipe 38. The second air outlet flow path 42b is located in the arrow Y2 direction of the fluid supply pipe 38. A first vacuum door 48a and a second vacuum door 48b are installed at the other end of the air outlet pipe 42. The first vacuum door 48a opens or blocks the first air outlet flow path 42a. The second vacuum door 48b opens or blocks the second air outlet flow path 42b.

[0024] The reaction fluid supply unit 16 includes a water tank 50, a water supply flow path 52, a water vapor generator 54, a water vapor outlet flow path 56, a mixing unit 58, a first supply flow path 60, a supply connection pipe portion 62, and a second supply flow path 64. The water tank 50 stores water generated, for example, in an external factory. However, the water tank 50 may also store city water. The water supply flow path 52 introduces the water stored in the water tank 50 into the water vapor generator 54. The water vapor generator 54 generates water vapor by heating the water introduced from the water supply flow path 52. The water vapor generator 54 can heat water using the heating fluid discharged from the heat storage space 34 via the fluid discharge flow path 40a.

[0025] The water vapor outlet flow path 56 introduces the water vapor generated in the water vapor generator 54 into the mixing section 58. The mixing section 58 mixes the water vapor as one reaction fluid and the CO2 gas as the other reaction fluid. The CO2 gas supplied to the mixing section 58 uses, for example, CO2 gas generated in an external factory or the like. The first supply flow path 60 supplies the reaction fluid (water vapor and CO2 gas) led out of the mixing section 58 to the inner hole of the supply connection pipe section 62, that is, the supply connection flow path 62a.

[0026] The supply connection pipe portion 62 is provided in the shell member 14. Specifically, one end portion of the supply connection pipe portion 62 is airtightly joined to the third inner wall surface 28c. The other end portion of the supply connection pipe portion 62 is airtightly joined to the third outer wall surface 32c. The supply connection pipe portion 62 penetrates the third intermediate wall surface 30c. The middle portion of the supply connection pipe portion 62 is airtightly joined to the third intermediate wall surface 30c so that the heat storage space 34 and the vacuum space 36 are not connected to each other. The wall portion of the supply connection pipe portion 62 has a vacuum insulation space 63 in a manner surrounding the supply connection flow path 62a. The insulation space 63 is a closed space. The second supply flow path 64 supplies the reaction fluid derived from the supply connection flow path 62a to the electrolytic stack 12. That is, the second supply flow path 64 is located in the inner shell 28.

[0027] The synthesis gas outlet 18 includes a first outlet flow path 66, an outlet connecting pipe 68, and a second outlet flow path 70. The first outlet flow path 66 guides the synthesis gas discharged from the electrolytic stack 12 to the inner hole of the outlet connecting pipe 68, that is, the outlet connecting flow path 68a. The first outlet flow path 66 is located in the inner housing 28.

[0028] The lead-out connecting pipe portion 68 is provided on the shell member 14. Specifically, one end portion of the lead-out connecting pipe portion 68 is airtightly joined to the third inner wall surface 28c. The other end portion of the lead-out connecting pipe portion 68 is airtightly joined to the third outer wall surface 32c. The lead-out connecting pipe portion 68 penetrates the third intermediate wall surface 30c. The middle portion of the lead-out connecting pipe portion 68 is airtightly joined to the third intermediate wall surface 30c so that the heat storage space 34 and the vacuum space 36 are not connected to each other. The wall portion of the lead-out connecting pipe portion 68 has a vacuum insulating space 71 in a manner surrounding the lead-out connecting flow path 68a. The insulating space 71 is a closed space. The second lead-out flow path 70 guides the synthesis gas led out from the lead-out connecting flow path 68a to the methane production unit not shown.

[0029] The vacuum generating unit 20 includes a first pump introduction passage 72a, a first vacuum pump 74a, a first pump discharge passage 76a, a first pressure tank 78a, a second pump introduction passage 72b, a second vacuum pump 74b, a second pump discharge passage 76b, and a second pressure tank 78b.

[0030] The first vacuum pump 74a discharges the air of the vacuum space 36 through the first pump inlet flow path 72a and the first air outlet flow path 42a. The air discharged from the first vacuum pump 74a is stored in the first pressure tank 78a in a compressed state via the first pump discharge flow path 76a. The compressed air in the first pressure tank 78a is used as a transport fluid, for example, for guiding the water stored in the water tank 50 to the steam generator 54.

[0031] The second vacuum pump 74b discharges the air of the vacuum space 36 through the second pump inlet flow path 72b and the second air outlet flow path 42b. The air discharged from the second vacuum pump 74b is stored in the second pressure tank 78b in a compressed state via the second pump discharge flow path 76b. The compressed air in the second pressure tank 78b is used as a conveying fluid, for example, for guiding the water stored in the water tank 50 to the water vapor generator 54.

[0032] In the following description, the first vacuum pump 74a and the second vacuum pump 74b are sometimes referred to as vacuum pumps 74. In addition, the first pressure tank 78a and the second pressure tank 78b are sometimes referred to as pressure tanks 78. In the vacuum generating unit 20, there may be only one vacuum pump 74. In addition, in the vacuum generating unit 20, there may be only one pressure tank 78. In this case, the structure of the vacuum generating unit 20 is simplified.

[0033] The temperature adjustment unit 22 includes a first introduction flow path 80 , a stop valve 81 , a heater unit 82 , a second introduction flow path 84 , a cooling fluid supply unit 86 , and a cooling fluid introduction flow path 88 .

[0034] The first inlet flow path 80 guides the first heating fluid generated in the heating device 90 to the fluid supply flow path 38a. The heating device 90 is, for example, an external factory such as an ironworks or a garbage disposal site. In other words, the first heating fluid is a heat exhaust fluid generated in the external factory. Therefore, the temperature of the first heating fluid changes according to the operating state of the external factory. The stop valve 81 opens or blocks the first inlet flow path 80.

[0035] The heater section 82 blows a second heating fluid that is temperature-regulated to an appropriate temperature. That is, the heater section 82 has a blowing function. The second inlet flow path 84 introduces the second heating fluid blown from the heater section 82 into the middle portion of the first inlet flow path 80 (the portion of the first inlet flow path 80 that is downstream of the shut-off valve 81). The cooling fluid supply section 86, for example, has a blower that blows the atmosphere as a cooling fluid. However, the cooling fluid supply section 86 can also blow a fluid that has cooled the atmosphere as a cooling fluid. The cooling fluid inlet flow path 88 introduces the cooling fluid blown from the cooling fluid supply section 86 into the middle portion of the first inlet flow path 80 (the portion of the first inlet flow path 80 that is downstream of the shut-off valve 81).

[0036] The control unit 24 includes a computing unit (processing unit) and a storage unit. The computing unit can be composed of a processor (processing circuit) such as a CPU (Central Processing Unit). The computing unit includes an action control unit that controls the actions of the vacuum pump 74, the steam generator 54, the fluid supply gate 44, the fluid discharge gate 46, the first vacuum gate 48a, the second vacuum gate 48b, the stop valve 81, the heater unit 82, and the cooling fluid supply unit 86. The action control unit can be implemented by executing a program stored in the storage unit through the computing unit.

[0037] Next, the operating method of the electrolysis system 10 will be described.

[0038] When the electrolysis system 10 is put into operation, first, Figure 3 As shown, a vacuum process is performed to exhaust the air in the vacuum space 36 disposed between the intermediate housing 30 and the outer housing 32 (step S1). Specifically, in the vacuum process, the control unit 24 opens the first vacuum door 48a and the second vacuum door 48b. In addition, the control unit 24 drives the first vacuum pump 74a and the second vacuum pump 74b. Figure 1As shown, when the first vacuum pump 74a is driven, the air in the vacuum space 36 is led out to the first pressure tank 78a via the first air lead-out flow path 42a, the first vacuum door 48a, the first pump introduction flow path 72a, and the first pump discharge flow path 76a and stored in a compressed state. When the second vacuum pump 74b is driven, the air in the vacuum space 36 is led out to the second pressure tank 78b via the second air lead-out flow path 42b, the second vacuum door 48b, the second pump introduction flow path 72b, and the second pump discharge flow path 76b and stored in a compressed state.

[0039] Next, when the vacuum degree of the vacuum space 36 reaches the target vacuum degree, the control unit 24 closes the first vacuum door 48a and the second vacuum door 48b. In addition, the control unit 24 stops driving the first vacuum pump 74a and the second vacuum pump 74b. Thus, the vacuum process ends.

[0040] Next, a heat storage process is performed, that is, a heating fluid ( Figure 3 In the heat storage process, first, a heating process is performed ( Figure 4 Step S3). Specifically, the control unit 24 opens the fluid supply door 44, the fluid discharge door 46 and the stop valve 81. In addition, the control unit 24 drives the heater unit 82. As a result, the first heating fluid (heat exhaust fluid) is guided from the heating device 90 to the first inlet flow path 80. In addition, the second heating fluid is guided from the heater unit 82 to the first inlet flow path 80 via the second inlet flow path 84. The heating fluid containing the first heating fluid and the second heating fluid is supplied to the heat storage space 34 via the fluid supply door 44 and the fluid supply flow path 38a. When the heating fluid is supplied to the heat storage space 34, the low-temperature air in the heat storage space 34 is pushed by the heating fluid and discharged to the outside via the fluid discharge flow path 40a and the fluid discharge door 46. Accordingly, the heating fluid can be efficiently supplied to the heat storage space 34.

[0041] At this time, the heat of the first heating fluid changes according to the working state of the heating device 90. Therefore, in the heating process, the heat of the second heating fluid is changed according to the change of the heat of the first heating fluid so that the total heat of the first heating fluid and the second heating fluid is within the target heat range. That is, when the heat of the first heating fluid decreases, the control unit 24 controls the heater unit 82 to increase the heat of the second heating fluid. In addition, when the heat of the first heating fluid increases, the control unit 24 controls the heater unit 82 to decrease the heat of the second heating fluid.

[0042] Then, when the heat storage space 34 is filled with the heating fluid, the control unit 24 closes the fluid discharge door 46. As a result, the pressure of the heating fluid supplied to the heat storage space 34 increases, thereby raising the temperature of the heat storage space 34. In addition, during the heat storage process, since the vacuum space 36 functions as an insulating layer, it is possible to suppress the heat of the heating fluid introduced into the heat storage space 34 from being lost to the outside through the vacuum space 36. Therefore, the heat storage space 34 can be efficiently raised in temperature.

[0043] Next, the control unit 24 determines whether the temperature T of the heat storage space 34 has reached a predetermined temperature T1 (step S4). Here, the predetermined temperature T1 is set to a temperature slightly lower than the target temperature of the heat storage space 34. When the temperature T of the heat storage space 34 is lower than the predetermined temperature T1 (step S4: No), the process of step S4 is performed again. When the temperature T of the heat storage space 34 has reached the predetermined temperature T1 (step S4: Yes), the temperature adjustment process is performed (step S5).

[0044] In the temperature adjustment process, the control unit 24 shuts off the supply of the first heating fluid to the heat storage space 34 by closing the stop valve 81. That is, only the second heating fluid introduced from the heater unit 82 to the first introduction flow path 80 via the second introduction flow path 84 is supplied to the heat storage space 34. In this way, the temperature T of the heat storage space 34 can be finely adjusted simply. When the temperature T of the heat storage space 34 reaches the target temperature, the heat storage process is terminated.

[0045] Then, if Figure 3 As shown, the electrolysis process is started (step S6). That is, the control unit 24 guides the compressed air of at least one of the first pressure tank 78a and the second pressure tank 78b to the water tank 50. In addition, the control unit 24 drives the steam generator 54 and controls the electrolysis power supply (not shown) to apply voltage to the electrolysis stack 12.

[0046] Then, the water stored in the water tank 50 is pushed by the compressed air and guided to the steam generator 54 via the water supply flow path 52. In the steam generator 54, the water introduced from the water supply flow path 52 is heated to generate steam. The steam generated by the steam generator 54 is guided to the mixing section 58 via the steam outlet flow path 56. In the mixing section 58, the steam introduced from the steam outlet flow path 56 and the CO2 gas supplied from an external factory or the like are mixed. The reaction fluid (steam and CO2 gas) mixed in the mixing section 58 is supplied to the electrolytic stack 12 via the first supply flow path 60, the supply connection flow path 62a, and the second supply flow path 64.

[0047] The reaction gas supplied to the electrolytic stack 12 is supplied to the cathode electrode of each electrolytic cell 26 and electrolyzed (co-electrolysis). That is, water vapor is electrolyzed to generate hydrogen, and CO2 gas is electrolyzed to generate CO gas (carbon monoxide gas). The synthesis gas containing hydrogen and CO gas is supplied from the electrolytic stack 12 to the methane production unit (not shown) via the first outlet flow path 66, the outlet connecting flow path 68a, and the second outlet flow path 70. In addition, at this time, the electrolytic stack 12 generates heat by applying a voltage, and is surrounded by the heat storage space 34 and the vacuum space 36, so it can be kept warm at an appropriate temperature.

[0048] After starting the electrolysis process, the control unit 24 determines whether the operation is stopped due to an abnormality of the electrolytic stack 12 (step S7). If the operation is stopped due to an abnormality of the electrolytic stack 12 (step S7: Yes), the control unit 24 determines whether the temperature T of the heat storage space 34 is lower than the upper limit temperature Th (step S8).

[0049] When the temperature T of the heat storage space 34 is lower than the upper limit temperature Th (step S8: Yes), the heat preservation process (thermal standby mode) is performed (step S9). Specifically, the control unit 24 opens the fluid supply door 44 and supplies at least one of the first heating fluid and the second heating fluid to the heat storage space 34, thereby maintaining the temperature T of the heat storage space 34 within a predetermined temperature range. In this way, the temperature of the electrolytic stack 12 can be suppressed from dropping excessively, so that the time required to restart the operation can be shortened.

[0050] On the other hand, when the temperature T of the heat storage space 34 is higher than the upper limit temperature Th (step S8: No), the cooling process is performed (step S10). Specifically, the control unit 24 opens the fluid supply door 44 and the fluid discharge door 46, and introduces the cooling fluid from the cooling fluid supply unit 86 to the first introduction flow path 80 via the cooling fluid introduction flow path 88, thereby supplying the cooling fluid to the heat storage space 34. According to this, it is possible to suppress the excessive increase in the temperature of the electrolytic stack 12. At this time, the heating fluid discharged from the fluid discharge flow path 40a is guided to the steam generator 54 and used as a heat source for heating water.

[0051] Then, the control unit 24 determines whether the operation of the electrolytic stack 12 has been restarted (step S11). If the operation of the electrolytic stack 12 has not been restarted (step S11: No), the process returns to step S8. If the operation of the electrolytic stack 12 has been restarted (step S11: Yes), the process returns to step S7.

[0052] If the electrolytic stack 12 is not stopped due to abnormality (step S7: No), the control unit 24 determines whether the production amount of the synthesis gas has reached the target amount (step S12). If the production amount of the synthesis gas has not reached the target amount (step S12: No), the process returns to step S7.

[0053] When the production amount of the synthetic gas reaches the target amount (step S12: Yes), the electrolysis stop step is performed (step S13). That is, the control unit 24 stops applying voltage to the electrolysis stack 12 from the electrolysis power supply (not shown), and stops supplying the reaction gas to the electrolysis stack 12. Thus, a series of action flows of the operation method of the electrolysis system 10 are completed.

[0054] This embodiment has the following effects.

[0055] According to the present embodiment, the degree of vacuum in the vacuum space 36 can be adjusted by discharging the air in the vacuum space 36 to the outside from the air outlet passage 43. In addition, the temperature T of the heat storage space 34 can be adjusted by supplying a heating fluid from the fluid supply passage 38a to the heat storage space 34. Thus, the temperature management of the electrolytic stack 12 can be easily performed.

[0056] The fluid supply flow path 38 a is located in the air outlet flow path 43 .

[0057] According to such a configuration, the temperature drop of the heating fluid flowing through the fluid supply flow path 38 a can be suppressed by the air lead-out flow path 43 .

[0058] The intermediate casing 30 is provided with a fluid discharge flow path 40 a for discharging the fluid in the heat storage space 34 .

[0059] According to such a configuration, the temperature T of the heat storage space 34 can be efficiently adjusted.

[0060] The electrolysis system 10 has a first introduction channel 80 and a second introduction channel 84. The first introduction channel 80 introduces the first heating fluid generated in the heating device 90 into the fluid supply channel 38a as the heating fluid. The second introduction channel 84 supplies the first introduction channel 80 with the second heating fluid as the heating fluid.

[0061] According to this configuration, even when the calorific value of the first heating fluid changes, the total calorific value of the first heating fluid and the second heating fluid can be maintained within a predetermined range by changing the calorific value of the second heating fluid.

[0062] The electrolysis system 10 includes a cooling fluid introduction flow path 88 for supplying the cooling fluid to the heat storage space 34 .

[0063] According to such a configuration, by supplying the cooling fluid to the heat storage space 34 , it is possible to suppress an excessive increase in the temperature of the electrolytic stack 12 .

[0064] The electrolysis system 10 includes a pressure tank 78 for storing in a compressed state the air discharged through the air discharge flow path 43. The compressed air stored in the pressure tank 78 is used as a transport fluid for transporting a fluid (for example, water) required for operating the electrolysis stack 12.

[0065] According to such a configuration, the compressed air generated when the vacuum space 36 is evacuated can be effectively utilized.

[0066] In the method of operating the electrolysis system 10 , the heat storage step is started after the vacuum step is completed.

[0067] According to such a method, it is possible to suppress the heat of the heating fluid supplied to the heat storage space 34 from being lost to the outside via the vacuum space 36 during the heat storage step.

[0068] The heat storage step includes a heating step in which both the first heating fluid generated in the heating device 90 and the second heating fluid for adjusting the temperature T of the heat storage space 34 are supplied to the heat storage space 34 .

[0069] According to such a method, the temperature of the heat storage space 34 can be efficiently increased by the first heating fluid and the second heating fluid.

[0070] The heat storage process includes a temperature adjustment process. In the temperature adjustment process, when the temperature T of the heat storage space 34 reaches a predetermined temperature T1 by the heating process, the supply of the first heating fluid to the heat storage space 34 is cut off and only the second heating fluid is supplied to the heat storage space 34 .

[0071] According to such a method, the temperature of the heat storage space 34 can be finely adjusted using the second heating fluid.

[0072] The operation method of the electrolytic stack 12 includes a heat preservation step. In the heat preservation step, after the electrolysis step is started, when the operation of the electrolytic stack 12 is stopped due to an abnormality and the temperature T of the heat storage space 34 is lower than the upper limit temperature Th, at least one of the first heating fluid and the second heating fluid is supplied to the heat storage space 34.

[0073] According to such a method, when the electrolytic stack 12 stops operating due to an abnormality, it is possible to suppress an excessive drop in the temperature of the electrolytic stack 12 , and thus it is possible to shorten the time required to resume operation.

[0074] The method for operating the electrolytic stack 12 includes a cooling step. In the cooling step, after the electrolytic step is started, when the electrolytic stack 12 stops due to an abnormality and the temperature T of the heat storage space 34 is equal to or higher than the upper limit temperature Th, a cooling fluid is supplied to the heat storage space 34 .

[0075] According to such a method, it is possible to suppress an excessive increase in the temperature of the electrolytic stack 12 when the operation of the electrolytic stack 12 is stopped due to an abnormality.

[0076] In addition, the present invention is not limited to the above-mentioned embodiment, and various structures can be adopted without departing from the gist of the present invention.

[0077] The above-mentioned implementation modes are summarized as follows.

[0078] The above embodiment discloses an electrolysis system (10), which has an electrolysis stack (12) formed by stacking a plurality of solid oxide-shaped electrolysis cells (26), and the electrolysis system (10) has an inner shell (28), an intermediate shell (30) and an outer shell (32), wherein the inner shell is used to accommodate the electrolysis stack; the intermediate shell surrounds the inner shell from the outside; the outer shell surrounds the intermediate shell from the outside, a heat storage space (34) is arranged between the inner shell and the intermediate shell, a vacuum space (36) is arranged between the intermediate shell and the outer shell, a fluid supply flow path (38a) for supplying a heating fluid to the heat storage space is provided in the intermediate shell, and an air outlet flow path (43) for discharging air in the vacuum space to the outside is provided in the outer shell.

[0079] In the above electrolysis system, the fluid supply flow path may be located within the air outlet flow path.

[0080] In the electrolysis system, the intermediate casing may be provided with a fluid discharge passage (40a) for discharging the fluid in the heat storage space.

[0081] In the above-mentioned electrolysis system, it can be: having a first inlet flow path (80) and a second inlet flow path (84), wherein the first inlet flow path is used to introduce the first heating fluid generated in the heating device (90) into the fluid supply flow path as the heating fluid; and the second inlet flow path supplies the second heating fluid as the heating fluid to the first inlet flow path.

[0082] The electrolysis system may include a cooling fluid introduction passage (88) for supplying cooling fluid to the heat storage space.

[0083] The electrolysis system may include a pressure tank (78) for storing the air discharged through the air discharge passage in a compressed state, and the compressed air stored in the pressure tank is used as a transport fluid for transporting a fluid required for the operation of the electrolysis stack.

[0084] The above-mentioned embodiment discloses an operation method of an electrolysis system, wherein the electrolysis system has an electrolysis stack formed by stacking a plurality of solid oxide-shaped electrolysis cells, and the electrolysis system has an inner shell, an intermediate shell and an outer shell, wherein the inner shell is used to accommodate the electrolysis stack; the intermediate shell surrounds the inner shell from the outside; and the outer shell surrounds the intermediate shell from the outside. The operation method of the electrolysis system includes a vacuum process, a heat storage process and a start electrolysis process, wherein in the vacuum process, air in a vacuum space arranged between the intermediate shell and the outer shell is discharged; in the heat storage process, a heating fluid is supplied to the heat storage space arranged between the inner shell and the intermediate shell; in the start electrolysis process, electrolysis by the electrolysis stack is started after the vacuum process and the heat storage process.

[0085] In the above-mentioned method for operating the electrolysis system, the heat storage step may be started after the vacuum step is completed.

[0086] In the above-mentioned operation method of the electrolysis system, the heat storage step may include a heating step, in which a first heating fluid generated in a heating device and a second heating fluid for adjusting the temperature (T) of the heat storage space are both supplied to the heat storage space.

[0087] In the operation method of the above-mentioned electrolysis system, it can be that: the heat storage process includes a temperature adjustment process. In the temperature adjustment process, when the temperature of the heat storage space reaches a specified temperature (T1) through the heating process, the supply of the first heating fluid to the heat storage space is cut off, and only the second heating fluid is supplied to the heat storage space.

[0088] The operation method of the electrolysis system may include a heat preservation step, in which, after the electrolysis step is started, when the operation of the electrolysis stack is stopped due to an abnormality and the temperature of the heat storage space is lower than an upper limit temperature (Th), the heating fluid is supplied to the heat storage space.

[0089] The method for operating the electrolysis system may include a cooling step in which, after the electrolysis start step, when the electrolysis stack stops due to an abnormality and the temperature of the heat storage space is above an upper limit temperature, a cooling fluid is supplied to the heat storage space.

[0090] In the operating method of the above-mentioned electrolysis system, the air exhausted from the vacuum space during the vacuum process can be stored in a pressure tank in a compressed state, and the compressed air stored in the pressure tank can be used as a transport fluid for transporting a fluid required for the operation of the electrolysis system.

Claims

1. An electrolysis system comprising an electrolysis stack formed by stacking a plurality of solid oxide-shaped electrolysis cells, characterized in that: The invention comprises an inner shell, an intermediate shell and an outer shell, wherein the inner shell is used to accommodate the electrolytic stack; the intermediate shell surrounds the inner shell from the outside; and the outer shell surrounds the intermediate shell from the outside. A heat storage space is arranged between the inner shell and the intermediate shell. A vacuum space is arranged between the intermediate housing and the outer housing. The intermediate casing is provided with a fluid supply flow path for supplying a heating fluid to the heat storage space. The outer housing is provided with an air outlet passage for discharging air in the vacuum space to the outside. The heat storage space is provided so as to cover the entire inner case from the outside.

2. The electrolysis system according to claim 1, characterized in that: The fluid supply flow path is located in the air outlet flow path.

3. The electrolysis system according to claim 1, characterized in that: The intermediate casing is provided with a fluid discharge flow path for discharging the fluid in the heat storage space.

4. The electrolysis system according to claim 1, characterized in that: There are a first inlet flow path and a second inlet flow path, wherein The first introduction flow path is used to introduce the first heating fluid generated in the heating device into the fluid supply flow path as the heating fluid; The second introduction flow path supplies a second heating fluid as the heating fluid to the first introduction flow path.

5. The electrolysis system according to claim 1, characterized in that: A cooling fluid introduction flow path is provided for supplying cooling fluid to the heat storage space.

6. The electrolysis system according to any one of claims 1 to 5, characterized in that: A pressure tank is provided, which stores the air discharged through the air discharge flow path in a compressed state, The compressed air stored in the pressure tank is used as a transport fluid for transporting a fluid required for operating the electrolytic stack.

7. A method for operating an electrolysis system, the electrolysis system having an electrolysis stack formed by stacking a plurality of solid oxide-shaped electrolysis cells, the method for operating the electrolysis system being characterized by: The electrolysis system comprises an inner shell, an intermediate shell and an outer shell, wherein: The inner shell is used to accommodate the electrolytic stack; the intermediate shell surrounds the inner shell from the outside; the outer shell surrounds the intermediate shell from the outside, The operation method of the electrolysis system includes a vacuum process, a heat storage process and a start electrolysis process, wherein: In the vacuum step, exhausting air from a vacuum space disposed between the intermediate housing and the outer housing; In the heat storage step, a heating fluid is supplied to a heat storage space disposed between the inner shell and the intermediate shell; In the electrolysis start step, after the vacuum step and the heat storage step, electrolysis by the electrolysis stack is started. The heat storage space is provided so as to cover the entire inner case from the outside.

8. The method for operating the electrolysis system according to claim 7, characterized in that: The heat storage step is started after the vacuum step is completed.

9. The method for operating an electrolysis system according to claim 7 or 8, characterized in that: The heat storage step includes a heating step of supplying both a first heating fluid generated in a heating device and a second heating fluid for adjusting the temperature of the heat storage space to the heat storage space.

10. The method for operating the electrolysis system according to claim 9, characterized in that: The heat storage step includes a temperature control step of shutting off supply of the first heating fluid to the heat storage space and supplying only the second heating fluid to the heat storage space when the temperature of the heat storage space reaches a predetermined temperature by the heating step.

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