Solid Oxide Electrolysis Cell System and Its Temperature Adaptive Regulation Method

Abstract

The present invention provides a solid oxide electrolyzer system and its temperature self-adaptive regulation method, including: a solid oxide electrolyzer module, and further including a thermochemical energy storage module coupled to the solid oxide electrolyzer module. The thermochemical energy storage module adjusts the working temperature and oxygen partial pressure during the electrochemical reaction process of the solid oxide electrolyzer module through its own redox reaction. By the reduction reaction of the thermochemical energy storage module to absorb heat and release oxygen, the working temperature of the solid oxide electrolyzer module can be reduced and the oxygen partial pressure can be increased; by using the heat released from the oxidation reaction of the thermochemical energy storage module to heat the solid oxide electrolyzer module and absorb oxygen, the working temperature of the solid oxide electrolyzer module can be increased and the oxygen partial pressure can be reduced, significantly changing the electrochemical reaction rate of the electrolysis process, maintaining the working temperature of the solid oxide electrolyzer module within a specified range, and reducing the temperature fluctuation amplitude of the solid oxide electrolyzer module.

Description

Technical Field

[0001] The present invention relates to the technical field of clean energy, and particularly to a solid oxide electrolyzer system and its temperature adaptive regulation method. Background Art

[0002] Facing the increasingly severe problems of energy resource constraints, environmental deterioration, etc., governments of many countries vigorously develop renewable energy such as solar energy and wind energy. However, the instability of the power generation of these renewable energy sources will affect the grid connection with the power grid, resulting in the waste of renewable energy. Therefore, there is an urgent need for an efficient energy storage system to convert the fluctuating renewable energy into a stable energy form.

[0003] A solid oxide electrolyzer (SOEC) can directly convert a H2O-CO2 mixture into syngas, which is one of the most competitive and promising technologies. Syngas can not only be directly used as fuel, but also be further synthesized into various hydrocarbons for downstream industries. The relatively high operating temperature of the solid oxide electrolyzer can reduce the electrical energy demand during the electrolysis process and bring a relatively high electrochemical reaction activity; however, the high operating temperature also poses a huge challenge to the thermal management of the solid oxide electrolyzer, especially when inputting fluctuating renewable energy.

[0004] With the fluctuation of the applied voltage, the solid oxide electrolyzer will have two working conditions of endothermic and exothermic. This unstable working condition switching will cause a significant change in the working temperature, generate a large temperature gradient and temperature change rate, thereby generating a large thermal stress, accelerating degradation and material failure. Therefore, advanced thermal management methods are needed to reduce the temperature fluctuation of the solid oxide electrolyzer under dynamic operating conditions. Summary of the Invention

[0005] Aiming at the above problems, the present invention provides a solid oxide electrolyzer system and its temperature adaptive regulation method. By coupling a thermochemical energy storage module with the solid oxide electrolyzer module, the temperature change and temperature gradient of the solid oxide electrolyzer module during the switching of endothermic and exothermic working conditions can be reduced; the technical problems of large temperature change and large temperature gradient of the solid oxide electrolyzer when storing renewable energy by using the solid oxide electrolyzer are solved.

[0006] The present invention provides a solid oxide electrolyzer system, including: a solid oxide electrolyzer module, and further including a thermochemical energy storage module coupled with the solid oxide electrolyzer module. The thermochemical energy storage module adjusts the working temperature and oxygen partial pressure during the electrochemical reaction process of the solid oxide electrolyzer module through its own redox reaction.

[0007] The working temperature and oxygen partial pressure are key parameters affecting the kinetic activity of the electrolysis process in a solid oxide electrolyzer module. Under high-temperature and low-oxygen partial pressure conditions, the electrolysis process has a high kinetic activity. The thermochemical energy storage module undergoes a reduction reaction to absorb and store the excess heat of the solid oxide electrolyzer module and release oxygen to the solid oxide electrolyzer module, which can reduce the working temperature of the solid oxide electrolyzer module and increase the oxygen partial pressure to inhibit the electrochemistry reaction activity; the thermochemical energy storage module undergoes an oxidation reaction to release heat for heating the solid oxide electrolyzer module and absorb the oxygen released by the solid oxide electrolyzer module, which can increase the working temperature of the solid oxide electrolyzer module and reduce the oxygen partial pressure to promote the electrochemistry reaction activity, significantly changing the electrochemical reaction rate of the electrolysis process, and maintaining the working temperature of the solid oxide electrolyzer module within a specified range and reducing the temperature fluctuation amplitude of the solid oxide electrolyzer module.

[0008] In an alternative technical solution of the present invention, it further includes an electric energy supply device for providing the electric energy required for the operation of the solid oxide electrolyzer module, and the electric energy comes from the fluctuating electric energy provided by a renewable energy power generation device. When the working voltage of the solid oxide electrolyzer module is higher than the specified thermal equilibrium voltage, the solid oxide electrolyzer module undergoes an exothermic reaction resulting in a temperature increase; when the working voltage is lower than the specified thermal equilibrium voltage, the solid oxide electrolyzer module undergoes an endothermic reaction resulting in a temperature decrease.

[0009] According to this technical solution, when the working voltage of the solid oxide electrolyzer module is higher than the thermal equilibrium voltage, the solid oxide electrolyzer module undergoes an exothermic reaction. When the temperature rises to the critical temperature at which the thermochemical energy storage module undergoes a reduction reaction, the thermochemical energy storage module undergoes a reduction reaction to absorb and store the heat released by the solid oxide electrolyzer module and release oxygen; when the working voltage is lower than the thermal equilibrium voltage, the solid oxide electrolyzer module undergoes an endothermic reaction. When the temperature drops to the critical temperature at which the thermochemical energy storage module undergoes an oxidation reaction, the thermochemical energy storage module undergoes an oxidation reaction to release heat and absorb oxygen.

[0010] The present invention directly uses fluctuating renewable energy as the electric energy input of the solid oxide electrolyzer module. It not only produces syngas through the solid oxide electrolyzer module but also effectively utilizes renewable energy, reducing the waste of renewable energy and providing a new solution to the problem of unstable renewable energy power generation; moreover, the fluctuating renewable energy source is clean, pollution-free, and has a considerable reserve, improving the utilization rate of renewable energy, being conducive to reducing production costs, and having significant economic benefits.

[0011] In an alternative technical solution of the present invention, the solid oxide electrolyzer module includes a cathode, an anode, an electrolyte between the cathode and the anode, a cathode gas channel, and an anode gas channel. The inlet of the cathode gas channel is connected to the outlet of the raw material gas supply device, the outlet of the cathode gas channel is connected to the inlet of the gas purification device, the inlet of the anode gas channel is connected to a blower device that provides air at a certain flow rate, and the outlet of the anode gas channel is directly connected to the external environment.

[0012] The structure of the solid oxide electrolyzer module of the present invention is simple, the manufacturing difficulty is low, and it is easy to reduce the production cost.

[0013] In an alternative technical solution of the present invention, the solid oxide electrolyzer module and the thermochemical energy storage module are coupled into an integrated device in a direct contact form, and the thermochemical energy storage module is installed in the anode gas channel.

[0014] According to this technical solution, the structure coupled in a direct contact form not only reduces the complexity of the solid oxide electrolyzer system and the thermal resistance during heat transfer, which is beneficial to the heat transfer between the thermochemical energy storage module and the solid oxide electrolyzer module; but also the installation of the thermochemical energy storage module in the anode gas channel facilitates the thermochemical energy storage module to absorb the oxygen of the anode and release anodes to the anode.

[0015] In an alternative technical solution of the present invention, the material type of the thermochemical energy storage module is the Co3O4 / CoO system, the CuO / Cu2O system, the Mn2O3 / Mn3O4 system, or a perovskite system capable of undergoing redox reactions.

[0016] According to this technical solution, the redox reaction temperature range of the above-mentioned type of thermochemical energy storage module matches the operating temperature of the solid oxide electrolyzer module, so that the operating conditions of the thermochemical energy storage module can vary within the operating temperature range of the solid oxide electrolyzer module, thereby reducing the temperature change and temperature gradient of the solid oxide electrolyzer module under the heat absorption and heat release conditions (especially during the switching of heat absorption and heat release conditions).

[0017] In an alternative technical solution of the present invention, the raw material gas provided by the raw material gas supply device is a certain proportion of water vapor and carbon dioxide.

[0018] According to this technical solution, water vapor and carbon dioxide as raw material gases have a wide source and low cost.

[0019] In an alternative technical solution of the present invention, the raw material gas supply device includes a steam generator, a CO2 storage tank, and a raw material gas mixing chamber. The steam generator and the CO2 storage tank are respectively connected to the raw material gas mixing chamber, and a water vapor flow meter, a CO2 flow meter, and a raw material gas flow meter are respectively connected to the outlet pipelines of the steam generator, the CO2 storage tank, and the raw material gas mixing chamber.

[0020] According to this technical solution, a steam generator is used to provide water vapor, a CO2 storage tank is used to provide CO2, the water vapor and CO2 are mixed in a raw gas mixing chamber, and a water vapor flowmeter, a CO2 flowmeter, and a raw gas flowmeter are respectively equipped at the outlet end to control the water vapor / CO2 ratio and the flow rate of the raw gas entering the solid oxide electrolysis cell module.

[0021] In an alternative technical solution of the present invention, the raw gas supply device includes a raw gas flow pipeline, and a heat insulation pipe is sleeved outside the raw gas flow pipeline.

[0022] According to this technical solution, the heat insulation pipe is beneficial to improving the heat preservation and heat insulation performance of the raw gas flow pipeline, increasing the service life of the raw gas flow pipeline, and reducing costs.

[0023] The present invention further provides a temperature adaptive regulation method for the above-mentioned solid oxide electrolysis cell system, including the following steps:

[0024] Cooling step: The thermochemical energy storage module undergoes a reduction reaction to absorb the heat of the solid oxide electrolysis cell module and release oxygen;

[0025] Heating step: The thermochemical energy storage module undergoes an oxidation reaction to release heat and absorb oxygen. Description of the Drawings

[0026] Figure 1 It is a schematic diagram of the solid oxide electrolysis cell system in the embodiment of the present invention.

[0027] Figure 2 It is a schematic structural diagram of the solid oxide electrolysis cell module in the embodiment of the present invention.

[0028] Figure 3 It is a schematic flow diagram of the temperature adaptive regulation method for the solid oxide electrolysis cell system in the embodiment of the present invention.

[0029] Reference Signs:

[0030] 1 - Raw gas supply device; 11 - Steam generator; 12 - CO2 storage tank; 13 - Raw gas mixing chamber; 14 - Water vapor flowmeter; 15 - CO2 flowmeter; 16 - Raw gas flowmeter; 2 - Overall equipment; 21 - Solid oxide electrolysis cell module; 211 - Cathode; 212 - Anode; 213 - Electrolyte; 214 - Cathode gas channel; 215 - Anode gas channel; 22 - Thermochemical energy storage module; 23 - Gas purification device; 3 - Electrolytic cell power supply device; 31 - Electrical switch; 4 - Fuel storage tank. Detailed Embodiments

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0032] As Figure 1 shown, an embodiment of the present invention provides a solid oxide electrolyzer system, including: a solid oxide electrolyzer module 21, and further including a thermochemical energy storage module 22 coupled to the solid oxide electrolyzer module 21. The thermochemical energy storage module 22 adjusts the working temperature and oxygen partial pressure during the electrochemical reaction process of the solid oxide electrolyzer module 21 through its own redox reaction.

[0033] The working temperature and oxygen partial pressure are key parameters affecting the kinetic activity of the electrolysis process of the solid oxide electrolyzer module 21. Under high temperature and low oxygen partial pressure conditions, the electrolysis process has higher kinetic activity. By the reduction reaction of the thermochemical energy storage module 22 to absorb and store the excess heat of the solid oxide electrolyzer module 21 and release oxygen to the solid oxide electrolyzer module 21, the working temperature of the solid oxide electrolyzer module 21 can be reduced and the oxygen partial pressure can be increased; by using the heat released by the oxidation reaction of the thermochemical energy storage module 22 to heat the solid oxide electrolyzer module 21 and absorb the oxygen released by the solid oxide electrolyzer module 21, the working temperature of the solid oxide electrolyzer module 21 can be increased and the oxygen partial pressure can be reduced, significantly changing the electrochemical reaction rate of the electrolysis process, maintaining the working temperature of the solid oxide electrolyzer module 21 within a specified range, and reducing the temperature fluctuation amplitude of the solid oxide electrolyzer module 21.

[0034] Specifically, in the embodiment of the present invention, the solid oxide electrolyzer system includes a raw gas supply device 1, a solid oxide electrolyzer module 21, a gas purification device 23, and a fuel storage tank 4 connected in sequence. The raw gas supply device 1 provides controllable proportions of water vapor and carbon dioxide as the raw gas for the reaction in the solid oxide electrolyzer module 21; the fuel storage tank 4 is used to collect the syngas flowing out of the outlet of the gas purification device 23. The present invention uses the thermochemical energy storage module 22 to store and release heat, assisting in the electrochemical reduction of CO2 and H2O to produce syngas, reducing the temperature fluctuation and temperature gradient of the solid oxide electrolyzer module 21 under the input of fluctuating renewable energy, being more flexible, faster, and more accurate than traditional thermal management methods, improving the operation safety of the electrolyzer and extending the service life of the solid oxide electrolyzer.

[0035] In a preferred embodiment of the present invention, an electrolytic cell power supply device 3 is further included, which is used to provide the electric energy required for the operation of the solid oxide electrolytic cell module 21. The electrolytic cell power supply device 3 is a renewable energy power supply device, which provides fluctuating electric energy to the solid oxide electrolytic cell module 21. When the operating voltage of the solid oxide electrolytic cell module 21 is higher than the specified thermal equilibrium voltage, the solid oxide electrolytic cell module 21 reacts to release heat, resulting in a temperature increase. When the operating voltage is lower than the specified thermal equilibrium voltage, the solid oxide electrolytic cell module 21 reacts to absorb heat, resulting in a temperature decrease.

[0036] According to this technical solution, when the operating voltage of the solid oxide electrolytic cell module 21 is higher than the thermal equilibrium voltage, the solid oxide electrolytic cell module 21 undergoes an exothermic reaction. When the temperature rises to the critical temperature at which the thermochemical energy storage module 21 undergoes a reduction reaction, the thermochemical energy storage module 22 undergoes a reduction reaction to absorb and store the heat released by the solid oxide electrolytic cell module 21 and release oxygen. When the operating voltage is lower than the thermal equilibrium voltage, the solid oxide electrolytic cell module 21 undergoes an endothermic reaction. When the temperature drops to the critical temperature at which the thermochemical energy storage module 21 undergoes an oxidation reaction, the thermochemical energy storage module 22 undergoes an oxidation reaction to release heat and absorb oxygen.

[0037] Further, in a preferred embodiment of the present invention, as Figure 2 shown, the solid oxide electrolytic cell module 21 includes a cathode 211, an anode 212, an electrolyte 213 between the cathode 211 and the anode 212, a cathode gas channel 214, and an anode gas channel 215. The inlet of the cathode gas channel 214 is connected to the outlet of the raw material gas supply device 1, and the outlet of the cathode gas channel 214 is connected to the gas purification device 23. The inlet of the anode gas channel 215 is connected to a blower device, and the thermochemical energy storage module 22 is arranged in the anode gas channel 215.

[0038] Specifically, both the anode 212 and the cathode 211 are porous cermet components; the electrolyte 213 is a dense ceramic component. The materials of the porous cermet components include nickel supported on zirconia, porous lanthanum strontium manganese composite, nickel-doped yttria-stabilized zirconia, etc. The materials of the dense ceramic components include yttria-stabilized zirconia, samarium-doped ceria, etc. The thickness of the cathode 211 is 20 μm - 30 μm, the thickness of the anode 212 is 300 μm - 500 μm, and the thickness of the electrolyte 213 is 8 μm - 20 μm. Preferably, the thickness of the anode 212 is 400 μm.

[0039] Further, the outlet of the gas purification device 23 is communicatively connected to the inlet of the fuel storage tank 4. The gas purification device 23 is configured to absorb the CO2 and H2O incorporated in the syngas, thereby improving the purity of the syngas and the conversion rate of the hydrocarbon fuel. Preferably, the gas purification device 23 is integrated between the solid oxide electrolysis cell module 21 and the fuel storage tank 4, and quicklime is filled in the gas purification device 23, which can absorb CO2 and H2O.

[0040] In the embodiment of the present invention, the raw material gas supplied by the raw material gas supply device 1 undergoes an electrochemical reaction at the cathode 211 of the solid oxide electrolysis cell module 21 to generate syngas CO and H2; O 2- diffuses to the surface of the anode 212 and is oxidized to generate O2. The mixture of the syngas and the raw material gas generated at the cathode 211 first enters the gas purification device 23, where the water vapor and CO2 are fully absorbed and then collected in the fuel storage tank 4.

[0041] Further, in a preferred embodiment of the present invention, the thermochemical energy storage module 22 is directly arranged in the anode gas channel 215 of the solid oxide electrolysis cell module 21 and integrated to form the overall device 2, and the anode 212 of the solid oxide electrolysis cell module 21 is in direct contact with the thermochemical energy storage module 22. The thermochemical energy storage module 22 adopts a porous structure, which does not affect the flow of air and the heat transfer and mass transfer between the air and the anode electrode. The direct contact structure not only reduces the complexity of the reversible electrolysis cell system, but also reduces the thermal resistance during heat transfer, which is beneficial to the heat transfer between the thermochemical energy storage module 22 and the solid oxide electrolysis cell module 21.

[0042] In a preferred embodiment of the present invention, the material type of the thermochemical energy storage module 22 is the Co3O4 / CoO system, the CuO / Cu2O system, the Mn2O3 / Mn3O4 system, or a perovskite system capable of undergoing redox reactions. The redox reaction temperature range of the thermochemical energy storage module 22 of the above types matches the operating temperature of the solid oxide electrolysis cell module 21, so that the operating conditions of the thermochemical energy storage module 22 can vary within the operating temperature range of the solid oxide electrolysis cell module 21, thereby reducing the temperature change and temperature gradient of the solid oxide electrolysis cell module 21 under the heat absorption and heat release conditions (especially during the switching of the heat absorption and heat release conditions). Specifically, the solid oxide electrolysis cell module 21 usually needs to be externally heated to 600-900 °C to achieve the conduction of oxygen ions; and it has high electrochemical activity. Among them, the redox reaction temperature range of Mn2O3 / Mn3O4 is 525-550 °C, and the redox reaction temperature range of cobalt oxide is 850-950 °C.

[0043] Preferably, the Co3O4 / CoO system is selected. The thermochemical energy storage module 22 utilizes the Co3O4 / CoO system to spontaneously undergo a conversion reaction when the temperature changes to the reaction node temperature, stores the waste heat released by the solid oxide electrolysis cell module 21 while absorbing oxygen, and spontaneously releases heat during the endothermic reaction, realizing the spontaneous thermal management of the solid oxide electrolysis cell module 21.

[0044] When the operating voltage of the solid oxide electrolysis cell module 21 is higher than the thermal neutral voltage, the solid oxide electrolysis cell module 21 releases heat, and the temperature increase causes a reduction reaction to occur in the thermochemical energy storage module 22, where Co3O4 is reduced to form CoO. This reaction absorbs heat and oxygen simultaneously; when the operating voltage is lower than the thermal neutral voltage, the solid oxide electrolysis cell module 21 absorbs heat, and the temperature decrease causes an oxidation reaction to occur in the thermochemical energy storage module 22, where CoO is oxidized to form Co3O4. This reaction releases heat and absorbs oxygen simultaneously. The oxidation-reduction reaction occurring in the thermochemical energy storage module 22 mitigates the temperature change and temperature gradient of the solid oxide electrolysis cell module 21 caused by the change in operating voltage, thereby reducing the thermal stress inside the solid oxide electrolysis cell module 21, improving the operating safety of the solid oxide electrolysis cell system, and extending the service life of the solid oxide electrolysis cell system.

[0045] Furthermore, in a preferred embodiment of the present invention, the raw material gas supply device 1 includes a steam generator 11, a CO2 storage tank 12, and a raw material gas mixing chamber 13. The outlet pipelines of the steam generator 11 and the CO2 storage tank 12 are respectively connected with a steam flowmeter 14 and a CO2 flowmeter 15 first and then communicated with the raw material gas mixing chamber 13. The outlet pipeline of the raw material gas mixing chamber 13 is connected with a raw material gas flowmeter 16 and then communicated with the solid oxide electrolysis cell module 21.

[0046] The steam generator 11 of the present invention is used to provide steam, the CO2 storage tank 12 is used to provide CO2, the raw material gas mixing chamber 13 is used to mix steam and CO2, and the settings of the steam flowmeter 14, the CO2 flowmeter 15, and the raw material gas flowmeter 16 can conveniently control the steam / CO2 ratio and the flow rate of the raw material gas entering the solid oxide electrolysis cell module 21.

[0047] Furthermore, in a preferred embodiment of the present invention, the electrolytic cell power supply device 3 is a renewable energy power generation device such as a solar concentrating heat storage power generation device, a wind power generation device, and a tidal energy power generation device. The voltages provided by these renewable energy power supply devices are all fluctuating. The energy sources of the new energy in the present invention have the advantages of universality, harmlessness, large reserves, and long-term use, improving the energy utilization rate and being beneficial to reducing production costs. The structures of the renewable energy power supply 31 in the present invention are all prior arts and will not be elaborated here.

[0048] The present invention uses renewable energy to supply electric power. On the one hand, compared with using fossil fuels to supply electric power, renewable energy, as a clean energy source, is inexhaustible and will not produce waste gas, waste water and waste residue, is green and pollution-free, can reduce the production cost of syngas and improve production efficiency. On the other hand, with the promotion of the construction of low-carbon and decarbonized energy systems in many countries, renewable energy has developed rapidly. However, due to the instability of its power generation, directly connecting to the grid will have an adverse impact on the grid, resulting in a waste of renewable energy.

[0049] The present invention directly uses a renewable energy power generation device that provides a fluctuating voltage as the power supply device 3 for the solid oxide electrolysis cell module 21. It not only produces syngas through the solid oxide electrolysis cell module 21, but also effectively utilizes renewable energy, reduces the waste of renewable energy, and provides a new solution to solve the problem of unstable power generation of renewable energy. In the embodiment of the present invention, when the supply of new energy in the form of solar energy, wind energy, etc. is sufficient, the electric energy required for the electrochemical reaction of the solid oxide electrolysis cell module 21 is completely provided by renewable energy. The solid oxide electrolysis cell module 21 is powered by a renewable energy power supply device, and the power has fluctuations and depends on the specific situation during the day. The thermochemical energy storage module 22 also solves the problem of unstable working temperature of the solid oxide electrolysis cell module 21 caused by the fluctuating voltage.

[0050] Specifically, the outlet of the electrolytic cell power supply device 3 is connected to the solid oxide electrolysis cell module 21 through an electrical switch 31, and the electrical switch 31 controls the conduction and disconnection of the current between it and the solid oxide electrolysis cell module 21. The setting of the electrical switch 31 can conveniently control the occurrence of the electrochemical reaction in the solid oxide electrolysis cell module 21.

[0051] Further, in the preferred embodiment of the present invention, the number of the solid oxide electrolysis cell modules 21 can be one or more. When the number of the solid oxide electrolysis cell modules 21 is greater than 1, the solid oxide electrolysis cell modules 21 are connected to the electrolytic cell power supply device 3 in series or parallel. Setting multiple solid oxide electrolysis cell modules 21 can produce syngas simultaneously, which is beneficial to improving the production efficiency of syngas.

[0052] Further, in the preferred embodiment of the present invention, each part of the raw material gas supply device 1 is connected through a raw material gas flow pipeline (not shown in the figure) externally wrapped with a heat insulation layer (not shown in the figure). The setting of the heat insulation pipe of the present invention is beneficial to improving the heat preservation and heat insulation performance of the raw material gas flow pipeline, beneficial to improving the service life of the raw material gas flow pipeline and reducing costs. Specifically, the heat insulation pipe is a ceramic pipe; the raw material gas flow pipeline is a stainless steel pipe.

[0053] The present invention further provides a production method for producing syngas by using the above-mentioned solid oxide electrolysis cell system with temperature self-regulation ability using unstable electric energy. The production method includes the following steps:

[0054] Syngas production step: The raw gas provided by the raw gas supply device 1 undergoes an electrochemical reaction at the cathode 211 of the solid oxide electrolysis cell module 21 to generate syngas.

[0055] Fuel collection step: The mixture of the raw gas and the syngas enters the gas purification device 23 to remove CO2 and H2O incorporated in the syngas, and the purified syngas enters the fuel storage tank 4.

[0056] It further includes a temperature adaptive regulation step of the solid oxide electrolysis cell system: As Figure 3 shown, in the cooling step, the thermochemical energy storage module undergoes a reduction reaction to absorb the heat of the solid oxide electrolysis cell module and release oxygen; in the heating step, the thermochemical energy storage module 22 undergoes an oxidation reaction to release heat to heat the solid oxide electrolysis cell module 21 and absorb oxygen.

[0057] Specifically, in the cooling step, when the voltage provided by the electrolytic cell power supply device 3 is higher than the thermal equilibrium voltage, the reaction for generating syngas in the solid oxide electrolysis cell module 21 is accompanied by the release of heat. At this time, the temperature rises to the temperature at which the thermochemical energy storage module 22 undergoes a reduction reaction, so that Co3O4 in the thermochemical energy storage module 22 is reduced to CoO, absorbing the heat released by the solid oxide electrolysis cell module 21 while releasing oxygen. The thermal energy is stored in the form of chemical energy. As the temperature rise trend of the solid oxide electrolysis cell module 21 becomes gentle and the oxygen partial pressure increases, the increase in the electrochemical reaction rate is gradually inhibited;

[0058] In the heating step, when the voltage provided by the electrolytic cell power supply device 3 is lower than the thermal equilibrium voltage, the reaction for generating syngas in the solid oxide electrolysis cell module 21 is accompanied by the absorption of heat (absorbing the heat of the thermochemical energy storage module 22). At this time, the temperature of the thermochemical energy storage module 22 decreases to the temperature at which the thermochemical energy storage module 22 undergoes an oxidation reaction, so that CoO in the thermochemical energy storage module 22 is oxidized to Co3O4 while absorbing oxygen, and the stored chemical energy is released in the form of thermal energy. As the temperature decrease trend of the solid oxide electrolysis cell module 21 becomes gentle and the oxygen partial pressure decreases, the decrease in the electrochemical reaction rate is gradually inhibited.

[0059] In the embodiment of the present invention, the thermochemical energy storage module 22 controls the electrochemical reaction rate by adjusting the working temperature and the oxygen partial pressure, and alleviates the temperature change and temperature gradient of the solid oxide electrolysis cell module 21 caused by the change of the working voltage.

[0060] In a preferred embodiment of the present invention, increasing the filling amount of the thermochemical energy storage module 22 is beneficial to alleviating the temperature and temperature gradient changes on the one hand, but on the other hand, it will reduce the energy density of the thermochemical energy storage module. In actual use, there is an optimal Co3O4 / CoO filling amount that meets the actual requirements.

[0061] Furthermore, different initial Co3O4 / CoO ratios have a relatively significant impact on the initial temperature response curve of the system. As time goes by, this impact gradually disappears.

[0062] Furthermore, the temperature of the feed gas at the inlet of the cathode gas channel 215 has a relatively obvious impact on the temperature gradient of the solid oxide electrolysis cell module 21. When the inlet feed gas temperature is maintained at 1123K, a relatively small temperature gradient of the solid oxide electrolysis cell module 21 can be obtained.

[0063] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A solid oxide electrolysis cell system, comprising: A solid oxide electrolysis cell module, characterized in that the solid oxide electrolysis cell module includes a cathode, an anode, an electrolyte between the cathode and the anode, a cathode gas channel and an anode gas channel. The inlet of the cathode gas channel is communicated with the outlet of a raw material gas supply device, the outlet of the cathode gas channel is communicated with the inlet of a gas purification device, the inlet of the anode gas channel is communicated with a blowing device which provides air at a certain flow rate, and the outlet of the anode gas channel is directly communicated with the external environment; the raw material gas supply device provides steam and carbon dioxide with controllable proportions as the raw material gas for the reaction in the solid oxide electrolysis cell module. It further includes a thermochemical energy storage module coupled with the solid oxide electrolysis cell module. The solid oxide electrolysis cell module and the thermochemical energy storage module are coupled into an integral device in a direct contact form, and the thermochemical energy storage module is installed in the anode gas channel; the thermochemical energy storage module adjusts the working temperature and oxygen partial pressure in the electrochemical reaction process of the solid oxide electrolysis cell module through its own redox reaction.

2. The solid oxide electrolysis cell system according to claim 1, wherein It further includes an electric energy supply device for providing the electric energy required for the operation of the solid oxide electrolysis cell module, and the electric energy comes from the fluctuating electric energy provided by a renewable energy power generation device; when the working voltage of the solid oxide electrolysis cell module is higher than the specified thermal equilibrium voltage, the reaction of the solid oxide electrolysis cell module releases heat and causes the temperature to rise; when the working voltage is lower than the specified thermal equilibrium voltage, the reaction of the solid oxide electrolysis cell module absorbs heat and causes the temperature to drop.

3. The solid oxide electrolysis cell system according to claim 1, characterized in that, The material type of the thermochemical energy storage module is the Co3O4 / CoO system, the CuO / Cu2O system, the Mn2O3 / Mn3O4 system or a perovskite system capable of undergoing a redox reaction.

4. The solid oxide electrolysis cell system according to claim 1, wherein The raw material gas supply device consists of a steam generator, a CO2 storage tank and a raw material gas mixing chamber. On the outlet pipelines of the steam generator and the CO2 storage tank, a steam flowmeter and a CO2 flowmeter are respectively connected first and then communicated with the raw material gas mixing chamber. On the outlet pipeline of the raw material gas mixing chamber, a raw material gas flowmeter is connected and then communicated with the solid oxide electrolysis cell module.

5. The solid oxide electrolysis cell system according to claim 1, characterized in that, The various parts of the raw material gas supply device are connected by a raw material gas flow pipeline wrapped with a heat insulation layer on the outside.

6. A temperature adaptive regulation method for a solid oxide electrolysis cell system according to any one of claims 1 to 5, characterized in that, It includes the following steps: Cooling step: The thermochemical energy storage module undergoes a reduction reaction to absorb the heat of the solid oxide electrolysis cell module and release oxygen. Heating step: The thermochemical energy storage module undergoes an oxidation reaction to release heat to heat the solid oxide electrolysis cell module and absorb oxygen.

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