阅读说明：本技术 集太阳能熔盐蓄热与sofc的发电储能一体化系统及工作方法 (Power generation and energy storage integrated system integrating solar fused salt heat storage and SOFC (solid oxide Fuel cell) and working method ) 是由 王朝阳 刘明 严俊杰 于 2021-08-27 设计创作，主要内容包括：本发明专利公开了集太阳能熔盐蓄热与SOFC的发电储能一体化系统及工作方法,整个系统应用于可再生能源发电并网与电网调峰运行领域。该系统包括太阳能集热器、熔融盐储罐、熔盐换热器、熔盐泵、风机、SOFC电堆、电子负载控制器、凝汽器、干燥器、间壁式换热器、管道、阀门、冷凝器、控制系统。本发明不仅可以用于向外发电供能,还可以从电网中获取能量,将电能转化为化学能存储,辅助电网调峰。(The invention discloses a power generation and energy storage integrated system integrating solar fused salt heat storage and SOFC (solid oxide fuel cell) and a working method, and the whole system is applied to the fields of renewable energy power generation grid connection and power grid peak regulation operation. The system comprises a solar heat collector, a molten salt storage tank, a molten salt heat exchanger, a molten salt pump, a fan, an SOFC (solid oxide fuel cell) electric pile, an electronic load controller, a condenser, a dryer, a dividing wall type heat exchanger, a pipeline, a valve, a condenser and a control system. The invention can be used for generating and supplying power to the outside, and can also obtain energy from a power grid, convert electric energy into chemical energy for storage and assist the peak regulation of the power grid.)

1. The integrated system for power generation and energy storage of the solar fused salt heat storage and SOFC is characterized by comprising a solar heat collection and heat storage unit and an SOFC power generation and energy storage unit,

the solar heat collection and storage unit comprises a solar heat collector (1), a molten salt expansion tank (2), a heater (3), a first molten salt pump (11), a second molten salt pump (8), a third molten salt pump (10), a first control valve (6), a second control valve (7), a third control valve (9), a low-temperature molten salt storage tank (5) and a high-temperature molten salt storage tank (4), the heater (3) is a molten salt/gas heat exchanger, the solar heat collector (1), the molten salt expansion tank (2), the first control valve (6), the molten salt side of the heater (3) and the first molten salt pump (11) are sequentially connected through pipelines to form a circulation loop, the high-temperature molten salt heat storage tank (4), the second molten salt pump (8), the second control valve (7), the heater (3) molten salt side, the third control valve (9), the third molten salt pump (10) and the low-temperature molten salt heat storage tank (5) are sequentially connected through pipelines to form a heat storage bypass;

the SOFC power generation and energy storage unit comprises an SOFC pile (12), an electronic load controller (13), a first heat regenerator (14), a second heat regenerator (15), a third heat regenerator (16), a fourth heat regenerator (20), a fifth heat regenerator (21), a three-way mixing valve (27), a first fan (31), a second fan (19), a water pump (28), a first hydrogen storage tank (30), a second hydrogen storage tank (26), a first oxygen storage tank (18), a second oxygen storage tank (17), a first water storage tank (29), a second water storage tank (24), a condenser (22), a steam-water separator (23), a drier (25), pipelines for connecting various devices and a pipeline for connecting the electronic load controller (13) and the SOFC pile (12), wherein,

the fuel side of the first water storage tank (29), the water pump (28) and the third heat regenerator (16) are sequentially connected through pipelines and are connected with a pipeline which is formed by connecting a first hydrogen storage tank (30), a first fan (31), the fuel side of the second heat regenerator (15) and the fuel side of the fifth heat regenerator (21) for the second time at a three-way mixing valve (27), the fuel side of the heater (3) enters the fuel inlet end of the SOFC electric pile (12), and a fuel outlet pipeline sequentially passes through the fuel side of the fifth heat regenerator (21), the fuel side of the fourth heat regenerator (20), the fuel side of the condenser (22), a steam-water separator (23) and a dryer (25) and is finally connected with the second hydrogen storage tank (26) to form a fuel closed pipeline;

the oxygen side of the first oxygen storage tank (18), the oxygen side of the second fan (19) and the oxygen side of the fourth heat regenerator (20), the oxygen side of the first heat regenerator (14), the oxygen side of the heater (3) and the oxygen inlet end of the SOFC electric stack (12) enter the oxygen inlet end, and the oxygen outlet pipeline enters the second oxygen storage tank (17) through the high-temperature oxygen side of the first heat regenerator (14), the oxygen side of the second heat regenerator (15) and the oxygen side of the third heat regenerator (16) to form an oxygen closed pipeline;

the SOFC pile (12) is connected with the electronic load controller (13) through a cable, and the electronic load controller (13) is connected with an external circuit to form a circuit loop.

2. The system according to claim 1, characterized in that the solar thermal collection and storage unit further comprises a second molten salt pump bypass valve (8') in parallel with the second molten salt pump (8), and a third molten salt pump bypass valve (10') in parallel with the third molten salt pump (10).

3. The method of operating the system of claim 1 or 2, wherein the solar thermal collection and storage unit comprises a normal cycle mode and a bypass thermal storage mode of operation, in particular as follows;

when the solar light is sufficient, starting a normal circulation mode, wherein the first control valve (6) is in an open state, the second control valve (7) and the third control valve (9) are in a closed state, starting the first molten salt pump (11), pressurizing molten salt by the first molten salt pump (11) and then entering the solar heat collector (1) for heating, enabling the heated molten salt to flow through the molten salt expansion tank (2) and then enter the heater (3) for heating a gas working medium of the power generation and energy storage unit, and enabling the molten salt to flow into an inlet of the solar heat collector (1) by the first molten salt pump (11) so as to finish a normal working mode of heat collection circulation;

when the solar illumination is insufficient, starting a bypass heat storage working mode, wherein the first control valve (6) is in a closed state, the second control valve (7) and the third control valve (9) are in an open state, starting the second molten salt pump (8), closing the second molten salt pump bypass valve (8') connected in parallel with the second molten salt pump, closing the third molten salt pump (10), opening the third molten salt pump bypass valve (10') connected in parallel with the third molten salt pump, and enabling the high molten salt of the heat storage bypass system to flow through the heater (3) to heat the gas working medium of the power generation and energy storage unit and flow into the low-temperature molten salt heat storage tank, so that the bypass heat storage working mode is started;

the SOFC power generation and energy storage unit comprises a power generation working mode and a hydrogen production energy storage working mode, and concretely comprises the following steps;

when the power grid needs electric energy, the SOFC power generation and energy storage unit starts a power generation mode to operate, at the moment, the current direction is controlled by the electronic load controller (13) to finish power supply to the outside, the second fan (19) is started to enable oxygen to flow through the SOFC pile (12), and the residual oxygen is collected into the second oxygen storage tank (17); opening a first fan (31) to lead out hydrogen in a first hydrogen storage tank (30), simultaneously opening a water pump (28), introducing a small amount of water in a first water storage tank (29) into a heater (16) by controlling the rotating speed of the water pump, mixing the water with the hydrogen in a three-way mixing valve (27), and finally allowing the mixed gas to flow into an SOFC (solid oxide fuel cell) stack (12) to perform electrochemical reaction with oxygen to supply power to the SOFC stack; the fuel gas which does not completely participate in the chemical reaction regenerates the gas which does not participate in the reaction through a fifth regenerator (21) and a fourth regenerator (20) by utilizing the high temperature of the fuel gas, and finally flows into a second hydrogen storage tank (26) through a condenser (22), a steam-water separator (23) and a dryer (25) to recover the fuel;

when the electric energy of the power grid is surplus, the SOFC power generation and energy storage unit starts a hydrogen production and energy storage mode to operate, the current direction is controlled by the electronic load controller (13) to absorb the external electric energy, the second fan (19) is started to flow a small amount of oxygen through the SOFC pile (12), and the oxygen electrolyzed by the SOFC pile (12) is collected into the second oxygen storage tank (17); a first fan (31) is turned on to lead out a small amount of hydrogen from a first hydrogen storage tank (30), a water pump (28) is turned on at the same time, water with a preset amount is taken from a first water storage tank (29) and is led into a third heat regenerator (16) by adjusting the rotating speed of the water pump, then the water and the hydrogen are mixed in a three-way mixing valve (27), and finally the mixed gas flows into an SOFC (solid oxide fuel cell) stack (12) to be electrolyzed so as to absorb external electric energy; hydrogen generated by chemical reaction and hydrogen input at the front end of the SOFC electric stack (12) sequentially pass through a fifth heat regenerator (21) and a fourth heat regenerator (20) to carry out heat regeneration on gas which does not participate in the reaction, and finally flow into a second hydrogen storage tank (26) through a condenser (22), a steam-water separator (23) and a dryer (25) to store the fuel.

Technical Field

The invention belongs to the field of energy sources such as SOFC power generation system operation and solar heat utilization, particularly relates to an integration technology of an SOFC power generation system and a solar heat storage system, and particularly relates to a power generation and energy storage integrated system taking an SOFC as a core component.

Background

In recent years, China accelerates the transformation of a propulsion energy structure, develops the power generation of renewable energy sources such as wind energy, solar energy and the like vigorously, and constructs a high-proportion renewable energy power generation system. But the renewable energy power generation has the characteristics of intermittency and periodicity, and the continuous and stable power supply of a power grid is difficult to be ensured by relying on the renewable energy. In addition, when the renewable energy power generation is excessive, the power grid cannot be consumed and directly stored. Therefore, in a future high-proportion renewable energy power generation system, the problem of mismatching of source-grid-load becomes increasingly prominent and becomes a bottleneck problem limiting the large-scale and high-efficiency development of renewable energy. The electric energy which cannot be timely consumed by the power grid in the renewable energy power generation system is converted into chemical energy in an easy storage form, and the flexibility and the energy utilization efficiency of the system can be effectively improved. Therefore, energy storage equipment is coupled in the renewable energy power generation system, and a power generation and energy storage integrated system is constructed, so that the method is an effective technical route for improving the operation flexibility and the efficiency of the renewable energy power generation system.

Sofc (sofc) is a clean, efficient, flexible energy conversion device that has both power generation and energy storage capabilities. The SOFC is used as a core component, the characteristics of power generation and energy storage are fully utilized, a power generation and energy storage integrated system is constructed, and the system is coupled with a wind energy, solar energy and other renewable energy power generation systems, so that the operation flexibility of the power generation system can be greatly improved, and the peak regulation pressure of a power grid is reduced. However, the SOFC needs to operate in a high-temperature environment of 600-1000 ℃, the SOFC is coupled with the solar fused salt heat absorption and storage device, and a reasonable configuration design is carried out on the coupled system, so that a high-efficiency and flexible power generation and energy storage integrated system can be constructed.

Therefore, the invention provides a power generation and energy storage integrated system integrating a solar molten salt heat storage device and an SOFC (solid oxide fuel cell) and a working method thereof.

Disclosure of Invention

In order to overcome the problems in the prior art, the invention aims to provide a power generation and energy storage integrated system and a working method for uniformly integrating solar fused salt heat storage and SOFC (solid oxide fuel cell). When the system is in the low ebb of the power grid, the SOFC galvanic pile starts an energy storage mode, and the redundant electric energy in the power grid is utilized to electrolyze water vapor to generate hydrogen and oxygen for storage; when the power grid is in a power consumption peak, the SOFC pile starts a power generation mode and transmits electric energy to the power grid. The method provides a theoretical basis for the construction and operation of a high-proportion renewable energy power generation system in the future.

In order to achieve the purpose, the technical scheme adopted by the invention for solving the technical problems is as follows:

the power generation and energy storage integrated system integrating solar fused salt heat storage and SOFC comprises a solar heat collection and storage unit and an SOFC power generation and energy storage unit,

the solar heat collection and storage unit comprises a solar heat collector 1, a molten salt expansion tank 2, a heater 3, a first molten salt pump 11, a second molten salt pump 8, a third molten salt pump 10, a first control valve 6, a second control valve 7, a third control valve 9, a low-temperature molten salt storage tank 5 and a high-temperature molten salt storage tank 4, wherein the heater 3 is a molten salt/gas heat exchanger, the solar heat collector 1, the molten salt expansion tank 2, the first control valve 6, a molten salt side of the heater 3 and the first molten salt pump 11 are sequentially connected through pipelines to form a circulation loop, and the high-temperature molten salt heat storage tank 4, the second molten salt pump 8, the second control valve 7, the molten salt side of the heater 3, the third control valve 9, the third molten salt pump 10 and the low-temperature molten salt heat storage tank 5 are sequentially connected through pipelines to form a heat storage bypass;

the SOFC power generation and energy storage unit comprises an SOFC pile 12, an electronic load controller 13, a first heat regenerator 14, a second heat regenerator 15, a third heat regenerator 16, a fourth heat regenerator 20, a fifth heat regenerator 21, a three-way mixing valve 27, a first fan 31, a second fan 19, a water pump 28, a first hydrogen storage tank 30, a second hydrogen storage tank 26, a first oxygen storage tank 18, a second oxygen storage tank 17, a first water storage tank 29, a second water storage tank 24, a condenser 22, a steam-water separator 23, a dryer 25, pipelines for connecting various devices and a line for connecting the electronic load controller 13 and the SOFC pile 12,

the fuel sides of the first water storage tank 29, the water pump 28 and the third heat regenerator 16 are sequentially connected through pipelines and are connected with a pipeline which is formed by connecting a first hydrogen storage tank 30, a first fan 31, a fuel side of the second heat regenerator 15 and a fuel side of the fifth heat regenerator 21 for secondary time at a three-way mixing valve 27, the fuel side of the heater 3 enters the fuel inlet end of the SOFC electric pile 12, and a fuel outlet pipeline sequentially passes through the fuel side of the fifth heat regenerator 21, the fuel side of the fourth heat regenerator 20, the fuel side of the condenser 22, the steam-water separator 23 and the dryer 25 and is finally connected with the second hydrogen storage tank 26 to form a fuel closed pipeline;

the oxygen side of the first oxygen storage tank 18, the oxygen side of the second fan 19, the oxygen side of the fourth heat regenerator 20, the oxygen side of the first heat regenerator 14, the oxygen side of the heater 3 and the oxygen inlet end of the SOFC electric stack 12 are arranged, and the oxygen outlet pipeline enters the second oxygen storage tank 17 through the high-temperature oxygen side of the first heat regenerator 14, the oxygen side of the second heat regenerator 15 and the oxygen side of the third heat regenerator 16 to form an oxygen closed pipeline;

the SOFC pile 12 is connected with an electronic load controller 13 through a cable, and the electronic load controller 13 is connected with an external circuit to form a circuit loop.

The solar heat collection and storage unit further comprises a second molten salt pump bypass valve 8 'connected in parallel with the second molten salt pump 8 and a third molten salt pump bypass valve 10' connected in parallel with the third molten salt pump 10.

According to the working method of the system, the solar heat collection and storage unit comprises a normal circulation mode and a bypass heat storage mode, and the working method comprises the following specific steps;

when the solar light is sufficient, starting a normal circulation mode, wherein the first control valve 6 is in an open state, the second control valve 7 and the third control valve 9 are in a closed state, starting the first molten salt pump 11, pressurizing the molten salt by the first molten salt pump 11, then heating the molten salt in the solar heat collector 1, enabling the heated molten salt to flow through the molten salt expansion tank 2 and further enter the heater 3 to heat the gas working medium of the power generation and energy storage unit, and enabling the molten salt to flow into the inlet of the solar heat collector 1 through the first molten salt pump 11, so as to finish the normal working mode of heat collection circulation;

when the solar illumination is insufficient, starting a bypass heat storage working mode, wherein the first control valve 6 is in a closed state, the second control valve 7 and the third control valve 9 are in an open state, starting the second molten salt pump 8, closing the second molten salt pump bypass valve 8' connected in parallel with the second molten salt pump 8', closing the third molten salt pump 10, opening the third molten salt pump bypass valve 10' connected in parallel with the third molten salt pump, and enabling the high molten salt in the heat storage bypass system to flow through the heater 3 to heat the gas working medium of the power generation and energy storage unit and flow into the low-temperature molten salt heat storage tank, so that the bypass heat storage working mode is started;

the SOFC power generation and energy storage unit comprises a power generation working mode and a hydrogen production energy storage working mode, and concretely comprises the following steps;

when the power grid needs electric energy, the SOFC power generation and energy storage unit starts a power generation mode to operate, at the moment, the current direction is controlled through the electronic load controller 13 to finish external power supply, the second fan 19 is started to enable oxygen to flow through the SOFC pile 12, and the residual oxygen is collected into the second oxygen storage tank 17; opening a first fan 31 to lead out hydrogen in a first hydrogen storage tank 30, simultaneously opening a water pump 28, controlling the rotating speed of the water pump, introducing a small amount of water in a first water storage tank 29 into a heater 16, mixing the water with the hydrogen at a three-way mixing valve 27, and finally allowing the mixed gas to flow into the SOFC stack 12 to perform electrochemical reaction with oxygen to supply power to the SOFC stack; the fuel gas which does not completely participate in the chemical reaction regenerates the unreacted gas through a fifth regenerator 21 and a fourth regenerator 20 by utilizing the high temperature of the fuel gas, and finally flows into a second hydrogen storage tank 26 through a condenser 22, a steam-water separator 23 and a dryer 25 to recover the fuel;

when the electric energy of the power grid is surplus, the SOFC power generation and energy storage unit starts a hydrogen production and energy storage mode to operate, the current direction is controlled by the electronic load controller 13 to absorb the external electric energy, the second fan 19 is started to flow a small amount of oxygen through the SOFC pile 12, and the oxygen electrolyzed by the SOFC pile 12 is collected into the second oxygen storage tank 17; a first fan 31 is turned on to lead out a small amount of hydrogen from a first hydrogen storage tank 30, a water pump 28 is turned on at the same time, water with a preset amount is taken from a first water storage tank 29 and is led into a third heat regenerator 16 by adjusting the rotating speed of the water pump, then the water and the hydrogen are mixed in a three-way mixing valve 27, and finally the mixed gas flows into an SOFC (solid oxide fuel cell) electric pile 12 to be electrolyzed so as to absorb external electric energy; the hydrogen generated by the chemical reaction and the hydrogen input at the front end of the SOFC stack 12 sequentially pass through the fifth heat regenerator 21 and the fourth heat regenerator 20 to regenerate heat to the gas which does not participate in the reaction, and finally flow into the second hydrogen storage tank 26 through the condenser 22, the steam-water separator 23 and the dryer 25 to store the fuel.

Compared with the prior art, the invention has the following advantages:

1) the invention can realize that working media inside the power generation and energy storage integrated system, including oxygen, water and fuel, are completely recycled under the working conditions of power generation mode, energy storage mode, mode switching and the like.

2) During the switching process of the operation mode, the power generation and energy storage integrated system does not need to be stopped, only needs to control the current direction through an electronic load, and simultaneously changes the relative proportion of hydrogen and water.

Drawings

FIG. 1 is a schematic diagram of a power generation and energy storage integrated system integrating solar molten salt heat storage and SOFC.

Detailed Description

In order to make the objects, technical solutions, and the like of the present invention more clearly understood, the present invention is further described below with reference to the accompanying drawings and the implementation examples. The specific embodiments described herein are merely illustrative of the invention and do not delimit the invention.

As shown in figure 1, the integrated power generation and energy storage system of the SOFC integrates solar molten salt heat storage and the SOFC, and comprises a solar heat collection and heat storage unit and an SOFC power generation and energy storage unit. The solar heat collection and storage unit comprises a solar heat collector 1, a molten salt expansion tank 2, a heater 3, a first molten salt pump 11, a second molten salt pump 8, a third molten salt pump 10, a first control valve 6, a second control valve 7, a third control valve 9, a low-temperature molten salt storage tank 5 and a high-temperature molten salt storage tank 4, wherein the heater 3 is a molten salt/gas heat exchanger, the solar heat collector 1, the molten salt expansion tank 2, the first control valve 6, a molten salt side of the heater 3 and the first molten salt pump 11 are sequentially connected through pipelines to form a circulation loop, and the high-temperature molten salt heat storage tank 4, the second molten salt pump 8, the second control valve 7, the molten salt side of the heater 3, the third control valve 9, the third molten salt pump 10 and the low-temperature molten salt heat storage tank 5 are sequentially connected through pipelines to form a heat storage bypass. The SOFC power generation and energy storage unit comprises an SOFC electric stack 12, an electronic load controller 13, a first heat regenerator 14, a second heat regenerator 15, a third heat regenerator 16, a fourth heat regenerator 20, a fifth heat regenerator 21, a three-way mixing valve 27, a first fan 31, a second fan 19, a water pump 28, a first hydrogen storage tank 30, a second hydrogen storage tank 26, a first oxygen storage tank 18, a second oxygen storage tank 17, a first water storage tank 29, a second water storage tank 24, a condenser 22, a steam-water separator 23, a dryer 25, pipelines for connecting various devices, and lines for connecting an electronic load and the SOFC electric stack.

The specific structure and connection of each unit are as follows:

the fuel sides of the first water storage tank 29, the water pump 28 and the third heat regenerator 16 are sequentially connected through pipelines and are connected with a pipeline which is formed by connecting a first hydrogen storage tank 30, a first fan 31, the fuel side of the second heat regenerator 15 and the fuel side of the fifth heat regenerator 21 for the second time at a three-way mixing valve 27, the fuel side of the heater 3 enters the fuel inlet end of the SOFC electric pile 12, and the fuel outlet pipeline sequentially passes through the fuel side of the fifth heat regenerator 21, the fuel side of the fourth heat regenerator 20, the fuel side of the condenser 22, the steam-water separator 23 and the dryer 25 and is finally connected with the second hydrogen storage tank 26 to form a fuel closed pipeline.

The system comprises a first oxygen storage tank 18, a second fan 19, a fourth regenerator 20, an oxygen side, a first regenerator 14, a heater 3, and an oxygen inlet end entering the SOFC stack 12, wherein an oxygen outlet pipeline passes through the high-temperature oxygen side of the first regenerator 14, the oxygen side of the second regenerator 15, the oxygen side of the third regenerator 16 and enters the second oxygen storage tank 17 to form an oxygen closed pipeline.

The SOFC pile 12 is connected with an electronic load controller 13 through a cable, and the electronic load controller 13 is connected with an external circuit to form a circuit loop.

The solar heat collection and storage unit comprises a normal circulation mode and a bypass heat storage working mode, and the specific working modes are as follows:

when the solar light is sufficient, a normal circulation mode is started, at the moment, the first control valve 6 is in an open state, the second control valve 7 and the third control valve 9 are in a closed state, the first molten salt pump 11 is started, the molten salt is pressurized by the first molten salt pump 11 and then enters the solar heat collector 1 to be heated, the heated molten salt flows through the molten salt expansion tank 2 and then enters the heater 3 to heat the gas working medium of the power generation and energy storage unit, and then the molten salt flows into the inlet of the solar heat collector (1) through the first molten salt pump 11, so that the normal working mode of heat collection circulation is completed.

When the solar illumination is insufficient, the bypass heat storage working mode is started, at the moment, the first control valve 6 is in a closed state, the second control valve 7 and the third control valve 9 are in an open state, the second molten salt pump 8 is started, the second molten salt pump bypass valve 8 'connected with the second molten salt pump bypass valve in parallel is closed, the third molten salt pump 10 is closed, the third molten salt pump bypass valve 10' connected with the third molten salt pump bypass valve in parallel is opened, and high molten salt in the heat storage bypass system flows through the heater 3 to heat gas working media of the power generation and energy storage unit and flows into the low-temperature molten salt heat storage tank, so that the bypass heat storage working mode is started.

The operation mode of the SOFC power generation and energy storage unit is as follows:

when the power grid needs electric energy, the SOFC power generation and energy storage unit starts a power generation mode to operate, at the moment, the current direction is controlled through the electronic load controller 13 to finish external power supply, the second fan 19 is started to enable oxygen to flow through the SOFC pile 12, and the residual oxygen is collected into the second oxygen storage tank 17; opening a first fan 31 to lead out hydrogen in a first hydrogen storage tank 30, simultaneously opening a water pump 28, controlling the rotating speed of the water pump, introducing a small amount of water in a first water storage tank 29 into a heater 16, mixing the water with the hydrogen at a three-way mixing valve 27, and finally allowing the mixed gas to flow into the SOFC stack 12 to perform electrochemical reaction with oxygen to supply power to the SOFC stack; the fuel gas which does not completely participate in the chemical reaction regenerates the unreacted gas through the fifth regenerator 21 and the fourth regenerator 20 by utilizing the high temperature of the fuel gas, and finally flows into the second hydrogen storage tank 26 through the condenser 22, the steam-water separator 23 and the dryer 25 to recover the fuel.

When the electric energy of the power grid is surplus, the SOFC power generation and energy storage unit starts an energy storage mode to operate, the current direction is controlled by the electronic load controller 13 to absorb the external electric energy, the second fan 19 is started to flow a small amount of oxygen through the SOFC pile 12, and the oxygen electrolyzed by the SOFC pile 12 is collected into the second oxygen storage tank 17; a first fan 31 is turned on to lead out a small amount of hydrogen from a first hydrogen storage tank 30, a water pump 28 is turned on at the same time, a proper amount of water is taken from a first water storage tank 29 and is led into a third heat regenerator 16 by adjusting the rotating speed of the water pump, then the water and the hydrogen are mixed in a three-way mixing valve 27, and finally the mixed gas flows into an SOFC (solid oxide fuel cell) electric pile 12 to be electrolyzed so as to absorb external electric energy; hydrogen generated by chemical reaction and hydrogen input at the front end of the SOFC pile 12 sequentially pass through a high-temperature fifth heat regenerator 21 and a fourth heat regenerator 20 to carry out heat regeneration on gas which does not participate in reaction, and finally flow into a second hydrogen storage tank 26 through a condenser 22, a steam-water separator 23 and a dryer 25 to store fuel.