Solid oxide electrolytic hydrogen production system and control method thereof

Abstract

The invention relates to the technical field of hydrogen energy, in particular to a solid oxide electrolytic hydrogen production system and a control method thereof.The electrolytic hydrogen production system comprises water, a waste heat recovery module, a fused salt phase change energy storage module and a solid oxide electrolytic tank, and the waste heat recovery module comprises a water preheater and a steam heater; product gas generated by the solid oxide electrolytic tank passes through the water preheater and the steam heater in sequence; the fused salt phase change energy storage module comprises a fused salt reactor heat release device and a phase change energy storage fused salt reactor for providing heat for the fused salt reactor heat release device; after being powered by the water pump, water sequentially passes through the water preheater, the molten salt pile heat release device and the steam heater to absorb heat, is converted into water vapor and then flows to the solid oxide electrolytic tank; the fused salt phase-change energy storage module stores energy by using high-temperature phase-change mixed salt, and can convert low-ebb and low-price off-peak electricity of a power grid and abandoned electricity such as photovoltaic electricity and wind electricity into heat energy for storage, so that the consumption of electric energy is reduced, the energy utilization rate is improved, and the hydrogen production cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen energy, and in particular to a solid oxide electrolysis hydrogen production system and a control method thereof. Background Art

[0002] As a secondary energy source, hydrogen has the advantages of zero pollution and no emissions, and the production of hydrogen by electrolyzing water using renewable energy does not produce carbon emissions during the preparation process.

[0003] At present, there are four main technologies for producing hydrogen by electrolysis of water, namely: alkaline water electrolysis (AEC), proton exchange membrane electrolysis (PEM), anion exchange membrane electrolysis (AEM) and solid oxide electrolysis (SOEC).

[0004] The solid oxide water electrolysis process utilizes high-temperature steam to produce hydrogen, significantly reducing the energy consumption of water electrolysis and improving energy efficiency, which is crucial for reducing the cost of hydrogen production. This technology has two major advantages: first, its high operating temperature, which creates more favorable thermodynamic conditions and reaction kinetics, thereby achieving higher conversion efficiency, and second, the technology does not require the use of precious metals as electrocatalysts.

[0005] Compared to the other three water electrolysis hydrogen production processes, solid oxide water electrolysis (SOEC) offers advantages such as high energy conversion efficiency, high current density, strong stability, and the absence of precious metal catalysts. It is a promising hydrogen production method. Compared to conventional water electrolysis, high-temperature steam electrolysis can increase hydrogen production efficiency by over 20%.

[0006] There are two types of solid oxide electrolyzers: proton-conducting SOECs (H-SOECs) and oxygen-ion-conducting SOECs (O-SOECs). Proton-conducting H-SOECs are suitable for operation at medium temperatures (500-750°C) and can produce pure hydrogen. Oxygen-ion-conducting O-SOECs operate at higher temperatures (700-1000°C) and have higher conversion efficiency. Solid oxide electrolyzers operate at high temperatures, but they neither absorb nor release heat, so the water vapor entering the electrolyzer must be at the operating temperature of the electrolyzer.

[0007] Currently, the water vapor for solid oxide electrolysis hydrogen production is provided by fuel boilers. The production of water vapor requires a certain amount of fuel, and the temperature of the water vapor generated by heating the raw water using conventional methods is generally only 150-250°C. Therefore, the water vapor needs to be heated before it can be passed into the electrolytic cell for electrolytic hydrogen production. Electric heating methods are usually used to heat the low-temperature water vapor to the operating temperature required by the electrolytic cell. However, due to the large temperature rise of water vapor, using electric heating methods to directly heat the water vapor to the operating temperature required by the electrolytic cell requires a large amount of electricity, resulting in increased costs.

[0008] The information disclosed in this background technology section is only intended to deepen the understanding of the overall background technology of the present invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art known to those skilled in the art. Summary of the Invention

[0009] In order to solve the above technical problems, the present invention provides a solid oxide electrolysis hydrogen production system and a control method thereof. The molten salt phase change energy storage module uses high-temperature phase change mixed salt to store energy, which can convert low-valley and low-price valley electricity of the power grid and abandoned electricity such as photovoltaic and wind power into thermal energy storage, and can make water vapor reach 500~750℃, thereby reducing electricity consumption, improving energy utilization, and reducing hydrogen production costs.

[0010] The first object of the present invention is to provide a solid oxide electrolysis hydrogen production system, which includes water, a waste heat recovery module, a molten salt phase change energy storage module, and a solid oxide electrolysis cell. The waste heat recovery module includes a water preheater and a steam heater. The product gas generated by the solid oxide electrolysis cell passes through the water preheater and the steam heater in sequence. The molten salt phase change energy storage module includes a molten salt pile heat release device and a phase change energy storage molten salt pile that provides heat for the molten salt pile; After being powered by a water pump, the water passes through a water preheater, a molten salt pile heat release device and a steam heater to absorb heat, and then turns into water vapor and flows to the solid oxide electrolysis cell.

[0011] As a preferred solution of the present invention, the molten salt reactor heat release device includes an upper diverter, a lower diverter and a pipe bank connecting the upper diverter and the lower diverter, and the pipe bank is located in the phase change energy storage molten salt reactor.

[0012] As a preferred solution of the present invention, an auxiliary electric heater for heating water vapor is provided between the steam heater and the solid oxide electrolysis cell.

[0013] As a preferred solution of the present invention, an industrial waste heat recovery device is further included, and the water is preheated by the industrial waste heat recovery device before entering the water preheater.

[0014] As a preferred solution of the present invention, during heat exchange, the product gas, water or steam pipeline is spiral-shaped.

[0015] As a preferred embodiment of the present invention, the electrolytic hydrogen production system further includes storage tanks for storing product gases.

[0016] As a preferred embodiment of the present invention, the electrolytic hydrogen production system further includes a DC power supply for supplying power to the solid oxide electrolysis cell.

[0017] As a preferred solution of the present invention, the electrolytic hydrogen production system further includes a carbon dioxide addition module.

[0018] A second object of the present invention is to provide a control method for the solid oxide electrolysis hydrogen production system, comprising: The product gas generated by the solid oxide electrolysis cell passes through a steam heater and a water preheater, and is stored after cooling; After the raw water is pressurized, it absorbs the heat of the product gas through the water preheater and is further heated by the molten salt phase change energy storage module to convert into water vapor; The water vapor absorbs the heat of the product gas through the steam heater and flows to the solid oxide electrolysis cell to be decomposed into product gas.

[0019] As a preferred embodiment of the present invention, when the product gases are hydrogen and oxygen, the hydrogen and oxygen are transported using independent pipelines.

[0020] Compared with the prior art, the present invention has the following beneficial effects: 1) The phase-change energy storage molten salt reactor is filled with high-temperature phase-change mixed salt. Electric heating rods are used to store energy during off-peak hours of the power grid or when renewable energy is abandoned. The temperature is maintained at 700-800°C. Using the phase-change energy storage molten salt reactor instead of electrically heating water vapor can convert low-valley, low-price electricity from the power grid and abandoned electricity from photovoltaic and wind power into thermal energy storage. The stored heat is used to heat water vapor, reducing the energy consumption of electric heating and lowering the cost of hydrogen production. The steam production process is stable and can also absorb unstable renewable energy. 2) This invention utilizes a tiered energy utilization system through the coordinated design of a waste heat recovery module, a molten salt phase change energy storage module, and an electrolytic cell. The raw water is first heated by absorbing the low-temperature waste heat of the product gas in a water preheater. The raw water is then vaporized into medium-temperature steam by a molten salt reactor heat release device, utilizing the thermal energy stored in off-peak / wasted electricity. Finally, the steam heater absorbs the high-temperature waste heat of the product gas to reach the electrolysis temperature. This process recovers both the high-temperature gas heat and the low-temperature waste heat, which are typically discharged directly in traditional processes. Combined with molten salt energy storage, this process significantly reduces electricity consumption and lowers hydrogen production costs. 3) The proton conduction type does not require auxiliary electric heating and directly uses waste heat and molten salt energy storage to complete the heating. The oxygen ion conduction type only needs to add a small amount of electricity to meet the high temperature requirements by adding an auxiliary electric heater. At the same time, the system can switch to the co-electrolysis mode through the carbon dioxide addition module to produce a mixture of hydrogen and carbon monoxide, expanding the diversified application scenarios from pure hydrogen preparation to synthesis gas production and improving industrial adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the structure of the solid oxide electrolysis hydrogen production system when the H-SOEC process is used in the present invention; Figure 2 Schematic diagram of the structure of the solid oxide electrolysis hydrogen production system when the O-SOEC process is used in the present invention; Figure 3 yes Figure 1 Schematic diagram of the structure after installing the industrial waste heat recovery device; Markings in the attached figure: 1. Waste heat recovery module; 11. Water preheater; 12. Steam heater; 2. Molten salt phase change energy storage module; 21. Molten salt reactor heat release device; 211. Upper diverter; 212. Lower diverter; 213. Pipe bank; 22. Phase change energy storage molten salt reactor; 3. Solid oxide electrolysis cell; 4. Auxiliary electric heater; 5. Industrial waste heat recovery device; 6. Storage tank; 7. DC power supply; 8. Carbon dioxide addition module. DETAILED DESCRIPTION

[0022] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0023] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0024] Secondly, the term "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0025] Reference Figure 1 This embodiment provides a solid oxide electrolysis hydrogen production system, which includes water, a waste heat recovery module 1, a molten salt phase change energy storage module 2, and a solid oxide electrolysis cell 3. The waste heat recovery module 1 includes a water preheater 11 and a steam heater 12. The product gas generated by the solid oxide electrolysis cell 3 passes through the water preheater 11 and the steam heater 12 in sequence. There are two combinations of product gases. The first combination is hydrogen and oxygen. High-temperature water vapor is introduced into the solid oxide electrolysis cell 3. Under the action of the DC power supply 7, the water vapor decomposes through the proton conduction or oxygen ion conduction mechanism in the electrolysis cell. The proton conduction type directly produces pure hydrogen and oxygen, and the oxygen ion conduction type achieves decomposition through ion migration at a higher temperature. The products are stored after waste heat recovery. The second combination is a mixture of hydrogen and carbon monoxide. A mixture of water vapor and carbon dioxide is introduced into the solid oxide electrolysis cell 3. Under high temperature conditions, the hydrogen in the water vapor and the carbon and oxygen in the carbon dioxide are recombined through a co-electrolysis reaction to produce a synthesis gas of hydrogen and carbon monoxide, which can be used as a chemical feed gas. More specifically, the water preheater 11 and the steam heater 12 may adopt shell-and-tube heat exchangers, which have independent hydrogen heat exchange tubes and oxygen heat exchange tubes (or synthesis gas heat exchange tubes) arranged inside, so as to realize heat exchange between the product gas and the raw water / water vapor through the tube wall. The shell-and-tube heat exchangers are suitable for high-temperature, high-pressure and corrosive gas environments, can efficiently recover the waste heat of the product gas, and have a sturdy structure and are easy to maintain.

[0026] The molten salt phase change energy storage module 2 includes a molten salt pile heat release device 21 and a phase change energy storage molten salt pile 22 that provides heat for the molten salt pile; More specifically, the phase-change energy storage molten salt reactor 22 is filled with a high-temperature phase-change mixed salt (such as a sodium nitrate-potassium nitrate mixed salt). The electric heating rod is used to store energy during off-peak periods of the power grid or when renewable energy is abandoned. The temperature is maintained at 700-800°C. The phase-change energy storage molten salt reactor 22 replaces the electric heating of steam. This converts off-peak, low-price off-peak electricity from the power grid, as well as abandoned electricity from photovoltaic and wind power, into thermal energy for storage. The stored heat is used to heat steam, reducing the energy consumption of electric heating and the cost of hydrogen production. Furthermore, the steam production process is stable and can also absorb unstable renewable energy. After being powered by the water pump, the water passes through the water preheater 11, the molten salt pile heat release device 21 and the steam heater 12 to absorb heat, and then is converted into water vapor and flows to the solid oxide electrolysis cell 3.

[0027] The specific working process of the solid oxide electrolysis hydrogen production system of the present invention is as follows: the water pump first sends the raw water into the water preheater 11, where it undergoes reverse heat exchange with the low-temperature product gas discharged from the solid oxide electrolysis cell 3, absorbing its low-temperature waste heat, and raising the temperature from room temperature to 150-250°C; then it enters the molten salt pile heat release device 21, where the water absorbs the heat stored in the molten salt as it flows upward, gradually vaporizing into water vapor at 400-600°C; the water vapor then flows into the steam heater 12, where it undergoes reverse heat exchange with the high-temperature product gas discharged from the electrolysis cell, absorbing its high-temperature waste heat and raising its temperature to 500-750°C; the qualified water vapor finally enters the solid oxide electrolysis cell 3 and is decomposed into hydrogen and oxygen under the action of the DC power supply 7; The high-temperature product gas generated by electrolysis first flows through the steam heater 12, releasing heat to heat the water vapor, and then flows through the water preheater 11 to release low-temperature waste heat to heat the raw water. Finally, it is cooled to room temperature and transported to the storage tank 6 through an independent pipeline for storage. The entire process achieves efficient heat utilization and step-by-step heating of the water vapor through the synergy of waste heat graded recovery and molten salt energy storage heat release. In the above process, since only the product gas and the molten salt phase change energy storage module 2 heat the water or water vapor, the temperature of the water vapor flowing out from the output end of the steam heater 12 is approximately 500~750℃. The water vapor in this temperature range is suitable for proton conduction H-SOEC to produce hydrogen by electrolysis.

[0028] In some embodiments of the present invention, reference Figure 1 The molten salt reactor heat release device 21 includes an upper diverter 211, a lower diverter 212 and a pipe bank 213 connecting the upper diverter 211 and the lower diverter 212. The pipe bank 213 is located in the phase change energy storage molten salt reactor 22. More specifically, the tube bank 213 is composed of multiple high-temperature resistant alloy tubes, which are evenly arranged vertically or spirally in the molten salt phase change energy storage module 2 and immersed in the high-temperature mixed salt of the phase change energy storage molten salt pile 22. The inner wall of the tube bank 213 is smooth to reduce water flow resistance, and the outer wall has a fin structure to enhance the heat exchange efficiency with the molten salt. The fluid distribution design of the upper flow divider 211 and the lower flow divider 212 ensures uniform flow across the multiple tube rows 213, avoiding the risk of vaporization delay or overheating due to uneven flow rates. Combined with the energy storage buffering function of the molten salt reactor, the system can maintain stable steam production during power grid fluctuations or intermittent power supply from renewable energy, thereby improving the continuous operation capability and anti-interference performance of the solid oxide electrolysis hydrogen production system. The specific working process of the molten salt pile heat release device 21 of the present invention is as follows: the raw water heated by the water preheater 11 enters from the lower diverter 212, flows upward along the tube row 213, absorbs the heat stored in the molten salt, and gradually vaporizes into water vapor at 400~600℃, and finally flows out from the outlet of the upper diverter 211 and is transported to the steam heater 12.

[0029] In some embodiments of the present invention, reference Figure 2 , an auxiliary electric heater 4 for heating water vapor is provided between the steam heater 12 and the solid oxide electrolytic cell 3; More specifically, the auxiliary electric heater 4 is a high-temperature resistant resistive electric heater (such as a nickel-chromium alloy heating element), with multiple layers of insulation material inside to reduce heat loss, and an external temperature sensor and PID controller to monitor and adjust the heating power in real time; Since the water vapor temperature required by the oxygen ion conduction type O-SOEC is higher (700-1000°C), an auxiliary electric heater 4 is added to the solid oxide electrolysis hydrogen production system matched with the above-mentioned proton conduction type H-SOEC. The auxiliary electric heater 4 is only activated when the O-SOEC requires a higher temperature. Relying on the preheating of the molten salt reactor and the steam heater 12, only a small amount of electrical energy is needed to heat the water vapor to the operating temperature required by the O-SOEC, and then enter the oxygen ion conduction type O-SOEC for electrolytic hydrogen production. Because the oxygen ion conduction type O-SOEC electrolysis hydrogen production has high conversion efficiency and fast reaction speed, it has better economic benefits. Therefore, using a small amount of electrical energy to heat the water vapor to a higher temperature for electrolytic hydrogen production will greatly reduce the overall cost.

[0030] In some embodiments of the present invention, reference Figure 3, further comprising an industrial waste heat recovery device 5, wherein the water is preheated by the industrial waste heat recovery device 5 before entering the water preheater 11; In situations where a large amount of industrial waste heat (such as hot water, hot gas, and hot process materials) can be utilized, in order to improve energy utilization and reduce the heat energy consumption of the molten salt reactor, an industrial waste heat recovery device 5 can be used. The raw water from the water pump is first sent to the industrial waste heat recovery device 5 for preliminary preheating, and then enters the water preheater 11. The heating chamber of the industrial waste heat recovery device 5 is connected to the industrial medium pipeline containing waste heat. The industrial waste heat recovery device 5 is applicable to either oxygen ion conduction type O-SOEC or proton conduction type H-SOEC.

[0031] In some embodiments of the present invention, reference Figure 1 , during heat exchange, the product gas, water or steam pipes are spiral; More specifically, the "heat exchange" here refers to the process in which the product gas passes through the water preheater 11 and the steam heater 12, the water passes through the industrial waste heat recovery device 5, and the water vapor passes through the auxiliary electric heater 4. During the heat exchange, the product gas, water or water vapor pipelines are set to a spiral shape. This can extend the flow path, induce a turbulent effect, increase the contact time between the fluid and the heat exchange medium, and enhance heat transfer, so that the waste heat of the product gas and the industrial waste heat can be more fully utilized in the water preheater 11, the steam heater 12, and the industrial waste heat recovery device 5, and the water vapor can be heated more evenly in the auxiliary electric heater 4. In coordination with the molten salt energy storage and waste heat graded recovery system, the system energy utilization rate is further improved, and the power consumption and hydrogen production cost are reduced.

[0032] In some embodiments of the present invention, reference Figure 1 The electrolysis hydrogen production system also includes storage tanks 6 for storing product gases. The product gases generated by electrolysis are centrally collected and temporarily stored through the provided storage tanks 6, which facilitate subsequent unified transportation, utilization or further processing.

[0033] In some embodiments of the present invention, reference Figure 1 The electrolysis hydrogen production system also includes a DC power supply 7 for powering the solid oxide electrolysis cell 3. The DC power supply 7 is used to provide stable DC power to the solid oxide electrolysis cell 3, drive the electrochemical reaction in the solid oxide electrolysis cell 3, decompose water vapor into hydrogen and oxygen at high temperature, or decompose and recombine water molecules and carbon dioxide molecules at high temperature, thereby producing hydrogen and carbon monoxide.

[0034] In some embodiments of the present invention, the electrolytic hydrogen production system also includes a carbon dioxide addition module 8. If the electrolytic hydrogen production system needs to produce hydrogen and carbon monoxide, carbon dioxide gas needs to be added to water vapor in proportion, and the mixed gas is sent to the solid oxide electrolysis cell 3 for electrolysis to obtain hydrogen and carbon monoxide.

[0035] A second object of the present invention is to provide a control method for the solid oxide electrolysis hydrogen production system, comprising: The product gas generated by the solid oxide electrolysis cell 3 passes through the steam heater 12 and the water preheater 11, and is stored after cooling; After the raw water is pressurized, it absorbs the heat of the product gas through the water preheater 11 and is then heated by the molten salt phase change energy storage module 2 and converted into water vapor; The water vapor absorbs the heat of the product gas through the steam heater 12 and flows to the solid oxide electrolysis cell 3 to be decomposed into product gas; More specifically, when the H-SOEC process is used, the control method of the solid oxide electrolysis hydrogen production system includes: S01: The raw water is pressurized to 1-4 MPa by a water pump and fed into the water preheater 11 (or first fed into the industrial waste heat recovery device 5 and then fed into the water preheater 11). The raw water absorbs the low-temperature waste heat contained in the hydrogen in the hydrogen heat exchange tube and the oxygen in the oxygen heat exchange tube in the water preheater 11, and the temperature is raised to 150-250°C. The raw water then enters the molten salt reactor heat release device 21 provided inside the phase change energy storage molten salt reactor 22; S02: The molten salt reactor heat release device 21 absorbs heat provided by the phase change energy storage molten salt reactor 22, heats the raw water and vaporizes it into water vapor. The water vapor continues to absorb heat in the tube bank 213 of the molten salt reactor heat release device 21, and the temperature rises to 400-600°C, and then enters the steam heater 12; S03: The water vapor absorbs the high-temperature waste heat contained in the hydrogen in the hydrogen heat exchange tube and the oxygen in the oxygen heat exchange tube in the steam heater 12, and the temperature rises to 500-750°C; S04: The flow rate of the raw water is controlled by the water pump. According to the feedback information from the temperature sensor of the water vapor at the outlet of the steam heater 12, the flow rate of the water pump is adjusted to ensure that the temperature of the water vapor at the outlet is constant at 500°C~750°C; S05: The steam from the steam heater 12 outlet is passed into the solid oxide electrolysis cell 3 (H-SOEC), where the steam is electrolyzed into hydrogen and oxygen; S06: The high-temperature hydrogen and oxygen from the electrolytic cell are divided into two paths and enter the hydrogen heat exchange pipe and oxygen heat exchange pipe in the steam heater 12, and the high-temperature waste heat contained in the hydrogen and oxygen is used to heat the water vapor. The low-temperature hydrogen and oxygen from the steam heater 12 are also divided into two paths and enter the hydrogen heat exchange pipe and oxygen heat exchange pipe in the water preheater 11, and the low-temperature waste heat contained in the hydrogen and oxygen is used to heat the raw water. S07: The hydrogen and oxygen coming out of the water preheater 11 are still divided into two paths and sent to the hydrogen collection tank and the oxygen collection tank respectively.

[0036] More specifically, when using the O-SOEC process, the control method of the solid oxide electrolysis hydrogen production system includes: S01: The raw water is pressurized to 1-4 MPa by a water pump and fed into the water preheater 11 (or first fed into the industrial waste heat recovery device 5 and then fed into the water preheater 11). The raw water absorbs the low-temperature waste heat contained in the hydrogen in the hydrogen heat exchange tube and the oxygen in the oxygen heat exchange tube in the water preheater 11, and the temperature is raised to 150-250°C. The raw water then enters the molten salt reactor heat release device 21 provided inside the phase change energy storage molten salt reactor 22; S02: The molten salt reactor heat release device 21 absorbs heat provided by the phase change energy storage molten salt reactor 22, heats the raw water and vaporizes it into water vapor. The water vapor continues to absorb heat in the tube bank 213 of the molten salt reactor heat release device 21, and the temperature rises to 400-600°C, and then enters the steam heater 12; S08: The water vapor absorbs the high-temperature waste heat contained in the hydrogen in the hydrogen heat exchange tube and the oxygen in the oxygen heat exchange tube in the steam heater 12, and the temperature rises to 600-850°C; S09: The flow rate of the raw water is controlled by the water pump. According to the feedback information from the temperature sensor of the water vapor at the outlet of the steam heater 12, the flow rate of the water pump is adjusted to ensure that the temperature of the water vapor at the outlet is constant at 600°C~850°C; S10: The auxiliary electric heater 4 heats the water vapor to a temperature of 700-1000°C; S11: The controller of the auxiliary electric heater 4 controls the heating power. According to the feedback information from the temperature sensor of the water vapor at the outlet of the auxiliary electric heater 4, the heating power of the auxiliary electric heater 4 is adjusted to ensure that the temperature of the water vapor at the outlet is constant at 700°C~1000°C; S12: The water vapor at the outlet of the auxiliary electric heater 4 is passed into the solid oxide electrolysis cell 3 (O-SOEC), where the water vapor is electrolyzed into hydrogen and oxygen; S13: The high-temperature hydrogen and oxygen from the electrolytic cell are divided into two paths and enter the hydrogen heat exchange pipe and oxygen heat exchange pipe in the steam heater 12, and the high-temperature waste heat contained in the hydrogen and oxygen is used to heat the water vapor. The low-temperature hydrogen and oxygen from the steam heater 12 are also divided into two paths and enter the hydrogen heat exchange pipe and oxygen heat exchange pipe in the water preheater 11, and the low-temperature waste heat contained in the hydrogen and oxygen is used to heat the raw water. S14: The hydrogen and oxygen coming out of the water preheater 11 are still divided into two paths and sent to the hydrogen collecting tank and the oxygen collecting tank respectively.

[0037] In some embodiments of the present invention, when the product gases are hydrogen and oxygen, hydrogen and oxygen are transported using independent pipelines to avoid safety risks caused by mixing flammable and explosive hydrogen with combustion-supporting oxygen, while preventing gas cross-contamination, ensuring the purity of hydrogen, and meeting the gas quality requirements for subsequent storage and utilization.

[0038] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A solid oxide electrolysis hydrogen production system, characterized in that: The electrolysis hydrogen production system comprises water, a waste heat recovery module (1), a molten salt phase change energy storage module (2) and a solid oxide electrolysis cell (3); the waste heat recovery module (1) comprises a water preheater (11) and a steam heater (12); the product gas generated by the solid oxide electrolysis cell (3) passes through the water preheater (11) and the steam heater (12) in sequence; The molten salt phase change energy storage module (2) comprises a molten salt pile heat release device (21) and a phase change energy storage molten salt pile (22) that provides heat to the molten salt pile; After being powered by a water pump, the water passes through the water preheater (11), the molten salt pile heat release device (21) and the steam heater (12) to absorb heat, and then is converted into water vapor and flows into the solid oxide electrolysis cell (3).

2. The solid oxide electrolysis hydrogen production system according to claim 1, characterized in that: The molten salt pile heat release device (21) comprises an upper diverter (211), a lower diverter (212), and a pipe row (213) connecting the upper diverter and the lower diverter; the pipe row (213) is located in the phase-change energy storage molten salt pile (22).

3. The solid oxide electrolysis hydrogen production system according to claim 1, characterized in that: An auxiliary electric heater (4) for steam heating is provided between the steam heater (12) and the solid oxide electrolysis cell (3).

4. The solid oxide electrolysis hydrogen production system according to claim 1 or 3, characterized in that: It also includes an industrial waste heat recovery device (5), and the water is preheated by passing through the industrial waste heat recovery device (5) before entering the water preheater (11).

5. The solid oxide electrolysis hydrogen production system according to claim 4, characterized in that: During heat exchange, the product gas, water or steam pipe is in a spiral shape.

6. The solid oxide electrolysis hydrogen production system according to claim 1, characterized in that: The electrolytic hydrogen production system further includes storage tanks (6) for storing the product gases.

7. The solid oxide electrolysis hydrogen production system according to claim 1, characterized in that: The electrolytic hydrogen production system further includes a direct current power supply (7) for supplying power to the solid oxide electrolysis cell (3).

8. The solid oxide electrolysis hydrogen production system according to claim 1, characterized in that: The electrolytic hydrogen production system further includes a carbon dioxide addition module (8).

9. The control method of the solid oxide electrolysis hydrogen production system according to claim 1, characterized in that: include: The product gas generated by the solid oxide electrolysis cell (3) passes through the steam heater (12) and the water preheater (11) in sequence, and is stored after being cooled; After the raw water is pressurized, it absorbs the heat of the product gas through the water preheater (11) and is then further heated by the molten salt phase change energy storage module (2) to be converted into water vapor; The water vapor absorbs the heat of the product gas through the steam heater (12) and flows to the solid oxide electrolysis cell (3) to be decomposed into the product gas.

10. The control method of the solid oxide electrolysis hydrogen production system according to claim 1, characterized in that: When the product gases are hydrogen and oxygen, the hydrogen and oxygen are transported using independent pipelines.

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