A soec water vapor electrolysis system

Abstract

The utility model relates to electrolytic water hydrogen production technical field, concretely relates to a SOEC water electrolysis steam system, including SOEC electric pile, water vapour input component, hydrogen input component, air input component, water vapour secondary heater, the hot side of water vapour secondary heater is arranged in the downstream of air input component, the upstream of SOEC electric pile anode entrance, the hot air in air input component enters SOEC electric pile anode via the hot side of water vapour secondary heater, the cold side of water vapour secondary heater is arranged in the downstream of water vapour input component and hydrogen input component, the upstream of SOEC electric pile cathode entrance, water vapour and hydrogen enter SOEC electric pile cathode via the cold side of water vapour secondary heater, the water vapour and hydrogen of cold side and the hot air of hot side exchange heat in water vapour secondary heater, and water vapour secondary heater is arranged as the counterflow heat exchanger to reduce the gas temperature difference of SOEC electric pile cathode entrance and SOEC electric pile anode entrance, and the temperature of cathode entrance and anode entrance of SOEC electric pile is controlled conveniently.

Description

Technical Field

[0001] This utility model relates to the field of water electrolysis for hydrogen production technology, specifically to an SOEC water electrolysis steam system. Background Technology

[0002] Solid oxide electrolysis cells (SOECs) are a high-temperature (600–900°C) water electrolysis technology for hydrogen production. The basic principle is to use solid oxide electrolytes to decompose water into hydrogen and oxygen at high temperatures. This technology has significant advantages such as high energy conversion efficiency, the ability to couple with high-temperature industrial waste heat, and the direct electrolysis of water vapor, and is considered one of the important technological pathways for achieving large-scale green hydrogen production.

[0003] In processes such as steelmaking, chemical engineering, nuclear power, or solar thermal power generation, the generated byproduct steam can be directly used as feed gas for SOEC (Solar Energy Storage and Reactor). Because SOEC operates at high temperatures, steam typically needs to be heated to over 700°C. Traditionally, this is done by preheating the steam with an electric heater. However, since the steam entering the SOEC stack needs to be mixed with some hydrogen, electric heating poses certain safety risks.

[0004] For SOEC fuel cell stacks, it is necessary to control the temperature difference between the anode and cathode, and the closer their temperatures are, the better. A common solution in existing technology is to use two separate electric heaters, which requires separate control and poses safety hazards. To eliminate these safety hazards, the industry has proposed a new steam heating method. Hot air and steam are introduced into a heat exchanger, allowing the hot air to exchange heat with the steam. The heated air is then introduced into the anode of the SOEC fuel cell stack, while the steam is introduced into the cathode. However, after the steam undergoes heat exchange, it mixes with room-temperature hydrogen, causing a temperature change in the mixture. This makes it difficult to control the temperature of the steam entering the cathode and the air entering the anode of the SOEC fuel cell stack, potentially resulting in a significant temperature difference. Summary of the Invention

[0005] 1. The problem to be solved In addressing the problem that the temperature of the water vapor introduced into the cathode inlet and the air temperature introduced into the anode inlet of the SOEC stack after heat exchange are difficult to control in existing technologies, and may have a large temperature difference, this utility model provides an SOEC electrolysis water vapor system that can accurately control the temperature of the cathode inlet and anode inlet of the SOEC stack.

[0006] 2. Technical Solution To solve the above problems, the technical solution adopted by this utility model is as follows: This utility model provides an SOEC electrolysis water vapor system, including an SOEC stack, a water vapor input component for inputting water vapor into the SOEC stack cathode, a hydrogen input component for inputting hydrogen into the SOEC stack cathode, and an air input component for inputting hot air into the SOEC stack anode. It also includes a steam secondary heater. The hot side of the steam secondary heater is located downstream of the air input assembly and upstream of the SOEC stack anode inlet. Hot air in the air input assembly enters the SOEC stack anode via the hot side of the steam secondary heater. The cold side of the steam secondary heater is located downstream of the steam input assembly and the hydrogen input assembly, and upstream of the SOEC stack cathode inlet. Steam and hydrogen enter the SOEC stack cathode via the cold side of the steam secondary heater. The secondary steam heater is configured as a co-current heat exchanger.

[0007] In a preferred embodiment of this utility model, the inlet end of the steam input component is connected to a steam source; The steam input assembly includes a steam pressure regulating valve, a pressure stabilizing tank, and a steam flow regulating valve arranged sequentially according to the steam flow direction, which are used to stabilize the steam pressure and flow rate in the steam input assembly. A venting branch is provided downstream of the steam flow regulating valve, and a venting valve is provided on the venting branch; The vent branch is located upstream of the point where water vapor and hydrogen mix to prevent hydrogen from leaking into the air.

[0008] As a preferred embodiment of this utility model, the pipe of the steam input component is wrapped with a second heat tracing cable for heating the steam in the pipe.

[0009] As a preferred embodiment of this utility model, the SOEC electrolysis water vapor system further includes a product hydrogen output component, which includes a condenser for separating hydrogen and water vapor, and a hydrogen circulation branch for inputting hydrogen to the SOEC stack cathode is connected downstream of the condenser.

[0010] As a preferred embodiment of this utility model, the hydrogen circulation branch is wrapped with a first heat tracing cable to prevent residual water vapor from condensing.

[0011] As a preferred embodiment of this utility model, the SOEC electrolysis steam system also includes a primary steam heater; The cold side of the primary steam heater is located upstream of the cold side of the secondary steam heater and downstream of the steam-hydrogen mixing point. The hot side of the steam primary heater is located downstream of the SOEC stack cathode outlet and upstream of the hot side of the condenser.

[0012] As a preferred embodiment of this utility model, the air input component includes an air filter, a blower, an air flow meter, and an electric heater arranged sequentially along the air flow direction.

[0013] As a preferred embodiment of this utility model, the SOEC water electrolysis steam system further includes a protective gas input component. The inlet end of the protective gas input component is connected to a protective gas source, and the protective gas input component is provided with two outlet ends. One outlet end is connected to the outlet end of the hydrogen input component, and the other outlet end is connected to an electric heater.

[0014] As a preferred embodiment of this utility model, the protective gas input component includes a protective gas gate valve, a protective gas pressure regulating valve, a first protective gas control valve, a protective gas filter, a protective gas flow meter, a protective gas regulating valve, and a first protective gas check valve arranged sequentially along the protective gas flow direction. The outlet end of the first protective gas check valve is connected to the outlet end of the hydrogen input component.

[0015] As a preferred embodiment of this utility model, a protective gas branch is also connected between the protective gas filter and the protective gas flow meter, and the protective gas branch is connected to the electric heater; a second protective gas control valve and a second protective gas check valve are sequentially arranged on the protective gas branch.

[0016] 3. Beneficial effects Compared with the prior art, the beneficial effects of this utility model are as follows: (1) This utility model uses the combination of SOEC stack, steam input component, hydrogen input component, air input component and co-current steam secondary heater, and the water vapor and hydrogen are mixed before entering the steam secondary heater, so that the water vapor and hydrogen on the cold side and the hot air on the hot side exchange heat in the steam secondary heater. As the flow in the heat exchanger, the temperature of the gas on the cold side and the hot side will gradually approach each other. Finally, the temperature of the water vapor and hydrogen discharged from the cold side and the hot air discharged from the hot side will approach the same, thus minimizing the temperature difference between the water vapor and hydrogen entering the cathode inlet and the air entering the anode inlet.

[0017] (2) Based on the fact that water vapor and hydrogen are mixed before entering the secondary water vapor heater, and the temperature of water vapor and hydrogen discharged from the cold side of the secondary water vapor heater is approximately equal to that of the hot air discharged from the hot side, this utility model only needs to adjust the temperature of the hot air input to the hot side of the secondary water vapor heater by the air input component, so as to accurately control the temperature of the cathode inlet and anode inlet of the SOEC stack. The operation is simple and easy to control. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of an SOEC water vapor electrolysis system.

[0019] Explanation of the labels in the diagram: 101. Steam gate valve; 102. Steam control valve; 103. Steam pressure regulating valve; 104. Pressure stabilizing tank; 105. Steam flow meter; 106. Steam regulating valve; 107. Check valve; 108. Relief valve; 109. Primary steam heater; 110. Secondary heating tape; 201. Air filter; 202. Blower; 203. Air flow meter; 204. Air preheater; 205. Electric heater; 206. Secondary steam heater; 301. First hydrogen flow meter; 302. First hydrogen check valve; 303. Condenser; 304. Hydrogen circulation pump; 305. Second hydrogen flow meter; 306. Second hydrogen check valve; 307. First heating tape; 308. First drain valve; 309. Second drain valve; 401. Hydrogen source; 402. Hydrogen gate valve; 403. Hydrogen pressure regulating valve; 404. Hydrogen control valve; 405. Hydrogen filter; 406. Third hydrogen flow controller; 407. Third hydrogen check valve; 501. Protective air source; 502. Protective air gate valve; 503. Protective air pressure regulating valve; 504. First protective air control valve; 505. Protective air filter; 506. Protective air flow meter; 507. Protective air regulating valve; 508. First protective air check valve; 509. Second protective air control valve; 510. Second protective air check valve.

[0020] 601, SOEC stack cathode; 602, SOEC stack anode. Detailed Implementation

[0021] To further understand the content of this utility model, a detailed description of this utility model will be provided in conjunction with the accompanying drawings and embodiments.

[0022] The structures, proportions, and sizes illustrated in the accompanying drawings are solely for illustrative purposes and to aid those skilled in the art in understanding and reading the invention. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, provided they do not affect the effectiveness or purpose of the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity and not intended to limit the scope of implementation. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0023] Example 1 This embodiment provides an SOEC electrolysis water vapor system, including: An SOEC fuel cell stack assembly comprises several SOEC stacks, each consisting of several individual cells stacked in series. Each SOEC stack includes an SOEC anode 602 and an SOEC cathode 601. The SOEC anode 602 has an anode inlet and an anode outlet, while the cathode has a cathode inlet and a cathode outlet. An electrolysis reaction occurs at the SOEC cathode 601. Water vapor is introduced into the SOEC cathode 601 and generates hydrogen gas. The exhaust gas from the SOEC cathode 601 is a mixture of hydrogen and water vapor.

[0024] The steam input component has its inlet end connected to a steam source and its outlet end connected to the cathode inlet. The steam input component is used to input the steam required for the electrolysis reaction into the SOEC stack cathode 601.

[0025] The hydrogen input component has its inlet end connected to the hydrogen source 401 and its outlet end connected to the cathode inlet, and is used to input hydrogen into the SOEC stack cathode 601.

[0026] The air input component has its inlet end connected to the outside air and its outlet end connected to the inlet of the SOEC fuel cell stack anode 602, and is used to input hot air into the SOEC fuel cell stack anode 602.

[0027] The steam secondary heater 206 is a co-current heat exchanger, comprising a cold side and a hot side. The hot side is located downstream of the air input assembly and upstream of the anode inlet of the SOEC stack; that is, the inlet of the hot side is connected to the outlet of the air input assembly, and the outlet of the hot side is connected to the anode inlet. Hot air heated by the air input assembly enters the SOEC stack anode 602 via the hot side of the steam secondary heater 206. The cold side is located downstream of the steam and hydrogen input assemblies and upstream of the cathode inlet of the SOEC stack; that is, the outlets of the steam and hydrogen input assemblies are directly or indirectly connected to the cold side, and the outlet of the cold side is connected to the cathode inlet. After mixing, steam and hydrogen enter the SOEC stack cathode 601 via the cold side.

[0028] For SOEC (Solar Orifice Computing) fuel cell stacks, it is necessary to control the temperature difference between the SOEC anode 602 and the SOEC cathode 601; the closer their temperatures are, the better. In this embodiment, water vapor and hydrogen on the cold side exchange heat with hot air on the hot side in a secondary water vapor heater 206. Since the secondary water vapor heater 206 is a co-current heat exchanger, and the water vapor and hydrogen mix before entering the secondary water vapor heater 206, as they flow in the heat exchanger, the temperatures of the gases on the cold and hot sides gradually approach each other. Eventually, the temperatures of the water vapor and hydrogen discharged from the cold side and the hot air discharged from the hot side become nearly the same, minimizing the temperature difference between the water vapor and hydrogen entering the cathode inlet and the air entering the anode inlet. Furthermore, based on the fact that the water vapor and hydrogen mix before entering the secondary water vapor heater 206, and the temperatures of the water vapor and hydrogen discharged from the cold side and the hot air discharged from the hot side are approximately equal, only the temperature of the hot air input to the secondary water vapor heater 206 by the air input component needs to be adjusted to precisely control the temperatures of the cathode and anode inlets of the SOEC fuel cell stack. This operation is simple and easy to control.

[0029] Example 2 Based on the above embodiments, the SOEC electrolysis water vapor system also includes a product hydrogen output component, whose inlet end is connected to the cathode outlet, for separating hydrogen and water vapor in the tail gas discharged from the SOEC stack cathode 601 outlet, and delivering the product hydrogen to a storage tank or other hydrogen-using equipment.

[0030] The product hydrogen output assembly includes a condenser 303, a first hydrogen check valve 302, and a first hydrogen flow meter 301, arranged sequentially along the hydrogen flow direction. The condenser 303 has cooling water inlet and outlet, connected to an external cooling system, used to cool the exhaust gas discharged from the SOEC stack cathode 601, causing water vapor to condense and separate from the hydrogen. The condensed water vapor is discharged to the system's drain outlet through a second drain valve 309 connected to the condenser 303, and collected for use as cooling water in the cooling system or as feed water for the water vapor input assembly. The first hydrogen flow meter 301 measures the total amount of product hydrogen, and the first hydrogen check valve 302 can only open in one direction (towards the product hydrogen discharge side).

[0031] A hydrogen recirculation branch is connected downstream of the condenser 303. This branch is used to re-input product hydrogen into the SOEC stack cathode 601, allowing the produced hydrogen to be recycled. After the system stabilizes, the hydrogen recirculation branch is used to supply hydrogen to the SOEC stack cathode 601, saving the external hydrogen source 401. The hydrogen recirculation branch should be connected before the first hydrogen flow meter 301 to prevent the first hydrogen flow meter 301 from including the hydrogen in the discharged product hydrogen. Preferably, it is located upstream of the first hydrogen check valve 302.

[0032] The mixing point of the hydrogen circulation branch and the water vapor should also be located upstream of the cold side of the water vapor secondary heater 206. Preferably, the hydrogen circulation branch and the pipelines of the water vapor input component and the hydrogen input component intersect at the same node, and the hydrogen and water vapor mix at this intersection point.

[0033] A hydrogen circulation pump 304, a second hydrogen flow meter 305, and a second hydrogen check valve 306 are sequentially arranged along the hydrogen flow direction on the hydrogen circulation branch. The hydrogen circulation pump 304 pumps hydrogen from the product hydrogen output assembly into the hydrogen circulation branch; the second hydrogen flow meter 305 measures the hydrogen flow rate in the hydrogen circulation branch; and the second hydrogen check valve 306 prevents backflow of gas downstream of the hydrogen circulation branch.

[0034] The hydrogen circulation branch pipe is wrapped with a first heating tape 307, which is used to heat the pipe and prevent the condensation of residual water vapor in the product hydrogen.

[0035] Example 3 Based on the above embodiments, the SOEC electrolysis steam system also includes a steam primary heater 109, which includes a cold side and a hot side.

[0036] The cold side of the primary steam heater 109 is located upstream of the cold side of the secondary steam heater 206 and downstream of the steam-hydrogen mixing point. That is, the cold side inlet of the primary steam heater 109 is directly or indirectly connected to the outlet of the steam input component, the outlet of the hydrogen input component, and the outlet of the hydrogen circulation branch. The cold side outlet of the primary steam heater 109 is connected to the cold side inlet of the secondary steam heater 206. After the steam and hydrogen are mixed, they pass through the cold side of the primary steam heater and the cold side of the secondary steam heater 206 in sequence, and enter the SOEC stack cathode 601 after two stages of heating.

[0037] The hot side of the steam primary heater 109 is located downstream of the cathode outlet and upstream of the hot side of the condenser 303; that is, the hot side inlet is connected to the outlet of the SOEC stack cathode 601, and the hot side outlet is connected to the hot side inlet of the condenser 303; the high-temperature exhaust gas discharged from the SOEC stack cathode 601 first enters the hot side of the steam primary heater 109 to exchange heat with the steam and hydrogen on the cold side, and then enters the condenser 303 for further cooling.

[0038] The steam primary heater 109 described above fully utilizes the waste heat from the exhaust gas discharged from the SOEC stack cathode 601 to preheat the steam and hydrogen, thereby increasing their temperature and simultaneously reducing the temperature of the cathode exhaust gas. This reduces the workload of the condenser 303 and decreases cooling water consumption.

[0039] Furthermore, to improve heat exchange efficiency, the primary steam heater is preferably a counter-flow tubular or plate heat exchanger.

[0040] Example 4 Based on the above embodiments, the inlet end of the steam input component is connected to a steam source, which can be by-product steam generated in the processes of steel, chemical, nuclear energy, or solar thermal power generation.

[0041] Specifically, the steam input component includes a steam gate valve 101, a steam control valve 102, a steam pressure regulating valve 103, a pressure stabilizing tank 104, a steam flow meter 105, a steam flow regulating valve 106, and a steam check valve 107 arranged sequentially according to the steam flow direction. After passing through the steam check valve 107, the steam mixes with the hydrogen input component or the hydrogen circulation branch input, and then enters the steam primary heater for preheating.

[0042] in: Steam gate valve 101 is a manually operated valve. It is closed during equipment shutdown and maintenance, and opened during equipment operation.

[0043] The steam control valve 102 is a normally closed valve that is opened during operation and closed when the machine is stopped or the power is cut off.

[0044] The steam pressure regulating valve 103 is used to regulate the pressure in the steam input pipeline. It can stabilize the pressure in the steam pipeline to the required pressure. It is preferably a self-operated pressure regulating valve that automatically regulates the pressure at the valve outlet.

[0045] The pressure stabilizing tank 104 is a pressure vessel with a certain volume, which can buffer the incoming water vapor, prevent excessive pressure fluctuations in the pipeline from causing rapid changes in water vapor flow, and reduce pressure fluctuations in the water vapor input pipeline caused by frequent fluctuations in the operating conditions of the water vapor source. The pressure stabilizing tank 104 is wrapped with thermal insulation material to prevent water vapor condensation. The pressure stabilizing tank 104 is also connected to a drain pipe, which is equipped with a first drain valve 308. The water vapor condensed in the pressure stabilizing tank 104 is discharged to the system's drain port through the first drain valve 308, and collected for use as cooling water in the cooling system or as raw water for the water vapor input components.

[0046] The steam flow meter 105 is used to measure the actual flow rate of steam. The steam flow rate is controlled by adjusting the opening of the steam flow regulating valve 106 to meet the steam flow rate requirements of the system.

[0047] In summary, through the coordinated regulation of the steam pressure regulating valve 103, the pressure stabilizing tank 104, and the steam flow regulating valve 106, the steam pressure in the pipeline can be kept stable even if the system is connected to different steam sources or the steam inlet pressure fluctuates. The steam flow is effectively controlled, ensuring stable system operation.

[0048] Furthermore, a venting branch is provided downstream of the steam flow regulating valve 106, and a venting valve 108 is installed on the venting branch. When the pressure in the steam pipeline exceeds the limit value, the venting valve 108 automatically opens to prevent overpressure and facilitates a rapid reduction in the pressure value in the pipeline under ultra-high pressure, allowing the pressure to quickly return to a stable level. The venting branch is located upstream of the point where steam and hydrogen mix to prevent hydrogen from leaking into the air.

[0049] Furthermore, a second heating tape 110 is wrapped around the pipe of the steam input component to heat the pipe and prevent condensation from forming inside the pipe due to low initial steam temperature or significant heat loss in a low-temperature environment. The power of the heating tape is adjusted according to the temperature of the steam inside the pipe to maintain a stable temperature of the steam discharged from the outlet of the steam input component. Preferably, the temperature of the steam entering the cold side of the primary steam heater is not lower than 200°C. Preferably, the second heating tape 110 is laid from the inlet end of the steam input component to the primary steam heater 109.

[0050] Example 5 Based on the above embodiments, the inlet end of the hydrogen input component is connected to the hydrogen source 401, which can be set as a hydrogen cylinder containing high-pressure hydrogen, mainly used to replenish hydrogen during the system's heating and cooling process.

[0051] The hydrogen input assembly includes a hydrogen gate valve 402, a hydrogen pressure regulating valve 403, a hydrogen control valve 404, a hydrogen filter 405, a third hydrogen flow controller 406, and a third hydrogen check valve 407 arranged sequentially along the hydrogen flow direction. After the hydrogen is discharged through the third hydrogen check valve 407, it mixes with the water vapor in the water vapor input assembly. The mixed gas is heated by the water vapor primary heater 109 and the water vapor secondary heater 206 before entering the SOEC stack cathode 601.

[0052] Example 6 Based on the above embodiments, the air input assembly includes an air filter 201, a blower 202, an air flow meter 203, an air preheater 204, and an electric heater 205 arranged sequentially along the air flow direction.

[0053] The blower 202 is used to draw outside air into the air input pipeline and make the air flow to the SOEC stack anode 602. The air flow can be controlled by adjusting the speed of the blower 202. The air filter 201 is used to filter impurities in the air. The air flow meter 203 is used to measure the air flow input to the SOEC stack anode 602.

[0054] Air preheater 204 is used to preheat incoming air. The incoming air enters the inlet of SOEC stack anode 602 through the cold side of air preheater 204, and the exhaust gas of SOEC stack anode 602 is discharged through the hot side of air preheater 204. The exhaust gas discharged from SOEC stack anode 602 is used to preheat the air and increase the air temperature. Air preheater 204 is preferably a counter-flow tubular or plate heat exchanger to improve heat exchange efficiency.

[0055] The preheated air then enters the electric heater 205 for further heating. The temperature of the hot air can be controlled by adjusting the power of the electric heater 205, thereby adjusting the temperature of the cathode inlet and anode inlet of the SOEC stack. The heated air then enters the hot side of the steam secondary heater 206 to heat the steam and hydrogen on the cold side of the steam secondary heater 206.

[0056] Example 7 Based on the above embodiments, the SOEC water electrolysis steam system also includes a protective gas input component. The inlet end of the protective gas input component is connected to a protective gas source 501. The protective gas is preferably nitrogen, and the protective gas source 501 can be configured as a nitrogen cylinder containing high-pressure nitrogen. The outlet end of the protective gas input component is connected to the outlet end of the hydrogen input component, used to input protective gas into the SOEC stack cathode 601 to protect the system during heating, cooling, or emergency conditions.

[0057] Specifically, the protective gas input component includes a protective gas gate valve 502, a protective gas pressure regulating valve 503, a first protective gas control valve 504, a protective gas filter 505, a protective gas flow meter 506, a protective gas regulating valve 507, and a first protective gas check valve 508 arranged sequentially along the protective gas flow direction. The protective gas mixes with water vapor after passing through the first protective gas check valve 508.

[0058] A protective gas branch is also connected between the protective gas filter 505 and the protective gas flow meter 506. A second protective gas control valve 509 and a second protective gas check valve 510 are sequentially installed on this branch. The protective gas branch is connected to the electric heater 205. When the blower 202 fails to operate normally under high temperature conditions, the second protective gas control valve 509 opens, introducing nitrogen gas into the electric heater 205 to prevent it from overheating.

[0059] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. An SOEC electrolysis water vapor system, comprising an SOEC stack, a water vapor input component for inputting water vapor into the SOEC stack cathode (601), a hydrogen input component for inputting hydrogen into the SOEC stack cathode (601), and an air input component for inputting hot air into the SOEC stack anode (602); Its features are, It also includes a secondary steam heater (206); The hot side of the steam secondary heater (206) is located downstream of the air input assembly and upstream of the SOEC stack anode (602) inlet. Hot air in the air input assembly enters the SOEC stack anode (602) via the hot side of the steam secondary heater (206). The cold side of the steam secondary heater (206) is located downstream of the steam input assembly and the hydrogen input assembly, and upstream of the SOEC stack cathode (601) inlet. Steam and hydrogen enter the SOEC stack cathode (601) via the cold side of the steam secondary heater (206). The steam secondary heater (206) is configured as a co-current heat exchanger.

2. The SOEC electrolysis steam system according to claim 1, characterized in that: The inlet of the steam input component is connected to a steam source; The steam input assembly includes a steam pressure regulating valve (103), a pressure stabilizing tank (104), and a steam flow regulating valve (106) arranged sequentially according to the steam flow direction, for stabilizing the steam pressure and flow rate in the steam input assembly; A venting branch is provided downstream of the steam flow regulating valve (106), and a venting valve (108) is provided on the venting branch. The vent branch is located upstream of the point where water vapor and hydrogen mix to prevent hydrogen from leaking into the air.

3. The SOEC electrolysis water vapor system according to claim 1, characterized in that: The pipe of the steam input component is wrapped with a second heat tracing tape (110) for heating the steam in the pipe.

4. The SOEC electrolysis steam system according to claim 1, characterized in that: It also includes a product hydrogen output assembly, which includes a condenser (303) for separating hydrogen and water vapor, and downstream of the condenser (303) is a hydrogen circulation branch for feeding hydrogen into the SOEC stack cathode (601).

5. The SOEC electrolysis water vapor system according to claim 4, characterized in that: The hydrogen circulation branch is wrapped with a first heat tracing cable (307) to prevent residual water vapor from condensing.

6. The SOEC water electrolysis steam system according to claim 4, characterized in that: It also includes a primary steam heater (109); The cold side of the primary steam heater (109) is located upstream of the cold side of the secondary steam heater (206) and downstream of the steam-hydrogen mixing point; The hot side of the steam primary heater (109) is located downstream of the outlet of the SOEC stack cathode (601) and upstream of the hot side of the condenser (303).

7. The SOEC electrolysis steam system according to any one of claims 1 to 6, characterized in that: The air input assembly includes an air filter (201), a blower (202), an air flow meter (203), and an electric heater (205) arranged sequentially along the air flow direction.

8. The SOEC electrolysis steam system according to claim 7, characterized in that: It also includes a protective gas input component, the inlet of which is connected to a protective gas source (501), and the protective gas input component is provided with two outlets, one of which is connected to the outlet of the hydrogen input component, and the other outlet is connected to an electric heater (205).

9. The SOEC electrolysis steam system according to claim 8, characterized in that: The protective gas input assembly includes a protective gas gate valve (502), a protective gas pressure regulating valve (503), a first protective gas control valve (504), a protective gas filter (505), a protective gas flow meter (506), a protective gas regulating valve (507), and a first protective gas check valve (508) arranged sequentially along the protective gas flow direction. The outlet end of the first protective gas check valve (508) is connected to the outlet end of the hydrogen input assembly.

10. The SOEC water electrolysis steam system according to claim 9, characterized in that: The protective gas filter (505) and the protective gas flow meter (506) are also connected by a protective gas branch, which is connected to the electric heater (205); a second protective gas control valve (509) and a second protective gas check valve (510) are sequentially arranged on the protective gas branch.

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