A reversible solid oxide fuel cell system

Abstract

The present invention discloses a reversible solid oxide fuel cell system, which belongs to the field of fuel cell technology, including a solid oxide fuel cell stack and a gas mixing tank, wherein the gas mixing tank is connected to a composite reformer through a No. 1 pipeline, connected to the water supply system through a No. 2 pipeline, connected to a CO2 supply system through a No. 3 pipeline, connected to an anode of the solid oxide fuel cell stack through a No. 4 pipeline, and a cathode inlet of the solid oxide fuel cell stack is connected to an air supply system. The present invention adopts the above-mentioned reversible solid oxide fuel cell system, which is a reversible solid oxide fuel cell system, and the system can be switched to a solid oxide fuel cell stack power generation system and a solid oxide fuel electrolysis cell by switching a valve as needed to adapt to changes in external working conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a reversible solid oxide fuel cell system. Background Art

[0002] The supply of renewable energy such as wind energy, solar energy, and tidal energy is affected by weather and natural conditions. Its energy supply mode is characterized by great instability, intermittency, and randomness, making it difficult to maintain a stable power supply condition, which has a great impact on the power grid. Hydrogen energy, as a highly efficient, clean, sustainable, and energy-dense secondary energy source, can serve as a bridge between the power grid and other energy sources, and "hydrogen production" and "hydrogen power generation" are two key nodes in the current development of hydrogen energy.

[0003] Reversible solid oxide cell (RSOC) can realize bidirectional energy conversion of hydrogen production and power generation in the same device. In SOFC mode, it can use hydrogen, natural gas and other fuels to generate electricity. In SOEC mode, it can also use energy to electrolyze H2O and co-electrolyze H2O and CO2 to produce H2 and CO. Compared with other electrolyzers and fuel cells, RSOC operates under medium and high temperature conditions, has higher energy conversion efficiency and a wider adjustable voltage range. It is a large-capacity, high charge / discharge cycle energy storage device suitable for unstable power supply conditions to regulate supply and demand. Summary of the invention

[0004] The purpose of the present invention is to provide a reversible solid oxide fuel cell system, which is a reversible solid oxide fuel cell system. The system can be switched into a solid oxide fuel cell stack power generation system and a solid oxide fuel electrolysis cell by switching valves as needed to adapt to changes in external working conditions.

[0005] To achieve the above-mentioned objectives, the present invention provides a reversible solid oxide fuel cell system, including a solid oxide fuel cell stack and a gas mixing tank, wherein the gas mixing tank is connected to a composite reformer via a No. 1 pipeline, connected to the water supply system via a No. 2 pipeline, connected to a CO2 supply system via a No. 3 pipeline, connected to an anode of the solid oxide fuel cell stack via a No. 4 pipeline, and the cathode inlet of the solid oxide fuel cell stack is connected to an air supply system.

[0006] Preferably, the cathode outlet and the anode outlet of the solid oxide fuel cell stack are both connected to the first waste heat utilization device.

[0007] Preferably, the cathode outlet pipeline of the No. 1 waste heat utilization device is connected to the fuel chamber and the composite heat exchanger through a No. 3 three-way valve, and the anode outlet pipeline of the No. 1 waste heat utilization device is connected to the combustion chamber and the composite reformer through a No. 4 three-way valve.

[0008] Preferably, the combustion chamber is connected to the composite heat exchanger and the composite reformer through an outlet pipeline.

[0009] Preferably, the composite reformer is connected to a gas storage tank after passing through a condenser.

[0010] Preferably, the combustion chamber is provided with a second fuel intake pipeline and a second air intake pipeline respectively.

[0011] Preferably, the air supply system comprises a No. 1 fan and a No. 2 fan, a No. 2 solenoid valve is provided between the No. 1 fan and the No. 1 air flow meter, and a No. 4 solenoid valve is provided between the No. 2 fan and the No. 2 air flow meter.

[0012] Preferably, the CO2 supply system includes a No. 5 solenoid valve and a No. 3 proton flowmeter, and the No. 3 proton flowmeter is connected to the gas mixing tank through a pipeline.

[0013] Preferably, the water supply system comprises a water tank, and the water tank is connected to the composite reformer and the gas mixing tank via a No. 2 three-way valve.

[0014] Preferably, one end of the composite heat exchanger is connected to the combustion chamber via a tee, and the other end thereof is connected to the No. 2 waste heat utilization device, and the No. 2 waste heat utilization device is connected to the composite reformer via a pipeline.

[0015] Therefore, the present invention adopts the above-mentioned reversible solid oxide fuel cell system, which is a reversible solid oxide fuel cell system. The system can be switched into a solid oxide fuel cell stack power generation system and a solid oxide fuel electrolysis cell by switching valves as needed to adapt to changes in external working conditions.

[0016] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a flow chart of an embodiment of a reversible solid oxide fuel cell system of the present invention.

[0018] Reference numerals

[0019] 1. Composite reformer; 2. Composite heat exchanger; 3. Solid oxide fuel cell stack; 4. Mixing tank; 5. Solenoid valve No. 1; 6. Proton flowmeter No. 1; 7. Three-way valve No. 1; 8. Fan No. 1; 9. Solenoid valve No. 2; 10. Air flowmeter No. 1; 11. Solenoid valve No. 3; 12. Proton flowmeter No. 2; 13. Fan No. 2; 14. Solenoid valve No. 4; 15. Air flowmeter No. 2; 16. Water tank; 17. Three-way valve No. 2; 18. Solenoid valve No. 5; 19. Proton flowmeter No. 3; 20. Waste heat utilization device No. 1; 21. Three-way valve No. 3; 22. Three-way valve No. 4; 23. Three-way valve No. 1; 24. Three-way valve No. 2; 25. Three-way valve No. 3; 26. Combustion chamber; 27. Three-way valve No. 5; 28. Waste heat utilization device No. 2; 29. ​​Condenser; 30. Gas storage tank. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0021] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0022] Embodiment 1

[0023] like Figure 1 As shown, the present invention provides a reversible solid oxide fuel cell system, including a solid oxide fuel cell stack 3 and a gas mixing tank 4. The fuel gas such as hydrogen and natural gas in the solid oxide fuel cell stack 3 undergoes an electrochemical reaction with air to convert chemical energy into electrical energy, and the gas enters the gas mixing tank 4 for mixing.

[0024] The cathode outlet and anode outlet of the solid oxide fuel cell stack 3 are both connected to the No. 1 waste heat utilization device 20, which is used to control the temperature of the water generated by the cathode part and the gas for the reaction. The cathode outlet pipeline of the No. 1 waste heat utilization device 20 is connected to the fuel chamber and the composite heat exchanger 2 through the No. 3 three-way valve 21, and the anode outlet pipeline of the No. 1 waste heat utilization device 20 is connected to the combustion chamber 26 and the composite reformer 1 through the No. 4 three-way valve 22. The composite heat exchanger 2 is used to utilize the heat in the tail gas. One end of the composite heat exchanger 2 is connected to the combustion chamber 26 through a three-way, and the other end is connected to the No. 2 waste heat utilization device 28. The No. 2 waste heat utilization device 28 is connected to the composite reformer 1 through a pipeline. The No. 2 waste heat utilization device 28 is used to utilize the waste heat of the tail gas, and the tail gas is directly discharged after the waste heat utilization.

[0025] The composite reformer 1 is connected to the gas storage tank 30 through the condenser 29. The condenser 29 is used to condense the generated gas, and the condensed water enters the water tank 16 through the pipeline. The combustion chamber 26 is connected to the composite heat exchanger 2 and the composite reformer 1 through the outlet pipeline. The combustion chamber 26 is respectively provided with a second fuel intake pipeline and a second air intake pipeline, and the combustion chamber 26 is used to mix the fuel gas and air for combustion.

[0026] The gas mixing tank 4 is connected to the composite reformer 1 through pipeline No. 1, connected to the water supply system through pipeline No. 2, connected to the CO2 supply system through pipeline No. 3, connected to the anode of the solid oxide fuel cell stack 3 through pipeline No. 4, and the cathode inlet of the solid oxide fuel cell stack 3 is connected to the air supply system.

[0027] The air supply system includes a No. 1 fan 8 and a No. 2 fan 13, and the No. 1 fan 8 and the No. 2 fan 13 are used to blow air. A No. 2 solenoid valve 9 is provided between the No. 1 fan 8 and the No. 1 air flow meter 10, and a No. 4 solenoid valve 14 is provided between the No. 2 fan 13 and the No. 2 air flow meter 15, and the No. 2 solenoid valve 9 and the No. 4 solenoid valve 14 are used to control whether to blow air.

[0028] The CO2 supply system includes a No. 5 solenoid valve 18 and a No. 3 proton flowmeter 19. The No. 3 proton flowmeter 19 is connected to the mixing tank 4 through a pipeline. The No. 3 proton flowmeter 19 is used to monitor the flow of CO2, and the No. 5 solenoid valve 18 is used to control whether CO2 is introduced.

[0029] The water supply system includes a water tank 16, which is connected to the composite reformer 1 and the gas mixing tank 4 through a No. 2 three-way valve 17. The water tank 16 is used to store water, and the No. 2 three-way valve 17 is used to control whether water is introduced into the water tank 16.

[0030] Working Principle: A reversible solid oxide fuel cell system, mainly divided into two modes:

[0031] 1. Relying on the electrochemical reaction between fuel gas such as hydrogen and natural gas and the air transmitted by the fan in the solid oxide fuel cell, chemical energy is converted into electrical energy.

[0032] Based on the power generation scheme of the above system, hydrogen enters the composite reformer 1 for heat exchange after passing through the No. 1 solenoid valve 5, the No. 1 proton flowmeter 6 and the No. 1 three-way valve 7. After passing through the composite reformer 1, the gas temperature is raised to 550-850°C. The heated gas passes through the mixing tank 4 and enters the anode part of the solid oxide fuel cell stack 3.

[0033] If methane is used, the No. 2 three-way valve 17 is opened before the composite reforming gas, so that water flows from the water tank 16 to the composite reformer 1 to undergo a reforming reaction with the introduced methane in the composite reformer 1. The temperature of the gas after the reaction rises to 700-850°C, and after passing through the mixing tank 4, it enters the anode part of the solid oxide fuel cell stack 3.

[0034] The air flows from the No. 1 fan 8 to the No. 2 solenoid valve 9, and after entering the No. 1 air flow meter 10, the fan speed is adjusted according to the specific flow size of the No. 1 air flow meter 10, thereby controlling the size of the air flow. After passing through the No. 1 air flow meter 10, the air enters the composite heat exchanger 2. After being heated by the composite heat exchanger 2, the gas temperature is 550-850°C, and the heated gas enters the cathode part of the solid oxide fuel cell stack 3.

[0035] An electrochemical reaction occurs in the solid oxide fuel cell stack 3, and direct current is output to the outside through an external circuit connected to the cathode and anode of the solid oxide fuel cell stack 3. The water generated in the anode part and the unreacted gas are temperature-controlled by the No. 1 waste heat utilization device 20, and the temperature-controlled gas passes through the No. 4 three-way valve 22, the No. 2 three-way valve 24, the No. 1 three-way valve 23 and the No. 3 three-way valve 25 before entering the combustion chamber 26. The gas after the reaction in the cathode part passes through the No. 1 waste heat utilization device 20 and temperature-controlled, and then passes through the No. 3 three-way valve 21, the No. 1 three-way valve 23 and the No. 3 three-way valve 25 before entering the combustion chamber 26.

[0036] According to actual working conditions, if the fuel utilization rate of the solid oxide fuel cell stack 3 is high, hydrogen or methane fuel can enter the combustion chamber 26 after passing through the No. 3 solenoid valve 11, the No. 2 proton flowmeter 12, the No. 2 tee 24, the No. 1 tee 23 and the No. 3 tee 25, and the air can enter the combustion chamber 26 after passing through the No. 2 fan 13, the No. 4 solenoid valve 14, the No. 2 air flowmeter 15 and the No. 3 tee 25, and then be mixed with the fuel gas and burned. The high-temperature exhaust gas after combustion passes through the No. 5 three-way valve 27 through the pipeline and enters the composite reformer 1 and the composite heat exchanger 2 respectively. After heat exchange, the exhaust gas temperature is reduced to 100-200°C, and then the exhaust gas enters the No. 2 waste heat utilization device 28, and the exhaust gas is discharged after the waste heat is utilized.

[0037] Second, relying on an external power source, water and air are transported to the anode and cathode of the solid oxide fuel cell respectively to react and produce hydrogen, converting electrical energy into chemical energy.

[0038] Based on the hydrogen production scheme of the above system, the gas mixing tank 4 and the solid oxide fuel cell stack 3 are placed in a high-temperature electric furnace. The water in the water tank 16 enters the gas mixing tank 4 after passing through the No. 2 three-way valve 17, and is heated to 600-850°C in the gas mixing tank 4. A trace amount of hydrogen enters the composite reformer 1 through the No. 1 solenoid valve 5 and the No. 1 proton flowmeter to control the flow rate 6, and then enters the gas mixing tank 4 for gas mixing.

[0039] If co-electrolysis is adopted, the CO2 gas enters the mixing tank 4 through the No. 5 solenoid valve 18 and the No. 3 proton flowmeter 19 for heating, and the heated mixed gas enters the anode part of the solid oxide fuel cell stack 3. The air flows from the No. 1 fan 8 to the No. 2 solenoid valve 9, passes through the No. 1 air flowmeter 10 and enters the compound heat exchanger 2. After heating through the compound heat exchanger 2, the heated gas is heated for a second time in a high-temperature electric furnace before entering the cathode part of the solid oxide fuel cell stack 3 to reach the target temperature. The direct current applied from the outside electrolyzes or co-electrolyzes the water and CO2 gas in the solid oxide fuel cell stack 3 through an external circuit connected to the anode and cathode of the solid oxide fuel cell stack 3.

[0040] After electrolysis, the anode part of the solid oxide fuel cell stack 3 generates hydrogen, which passes through the No. 1 waste heat utilization device 20 and then passes through the No. 4 three-way valve 22 to the composite reformer 1. After heat exchange, the generated gas passes through the condenser 29 for condensation, and the condensed water returns to the water tank 16 through the pipeline. The dehydrated gas is collected by the gas storage tank 30. The tail gas generated after the reaction is temperature-controlled by the No. 1 waste heat utilization device 20 and then passes through the No. 3 three-way valve 21 to the composite heat exchanger 2. After heat exchange, the waste heat is utilized by the No. 2 waste heat utilization device 28, and the tail gas is directly discharged after waste heat utilization.

[0041] Therefore, the present invention adopts the above-mentioned reversible solid oxide fuel cell system, which is a reversible solid oxide fuel cell system. The system can be switched into a solid oxide fuel cell stack power generation system and a solid oxide fuel electrolysis cell by switching valves as needed to adapt to changes in external working conditions.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A reversible solid oxide fuel cell system, characterized in that: It includes a solid oxide fuel cell stack and a gas mixing tank, wherein the gas mixing tank is connected to a composite reformer through a No. 1 pipeline, connected to a water supply system through a No. 2 pipeline, connected to a CO2 supply system through a No. 3 pipeline, connected to an anode of the solid oxide fuel cell stack through a No. 4 pipeline, and a cathode inlet of the solid oxide fuel cell stack is connected to an air supply system; Hydrogen or methane fuel is introduced into the combustion chamber through the No. 3 solenoid valve, the No. 2 proton flowmeter, the No. 2 tee, the No. 1 tee and the No. 3 tee; The cathode outlet and the anode outlet of the solid oxide fuel cell stack are both connected to a No. 1 waste heat utilization device; The cathode outlet pipeline of the No. 1 waste heat utilization device is connected to the fuel chamber and the composite heat exchanger through the No. 3 three-way valve, and the anode outlet pipeline of the No. 1 waste heat utilization device is connected to the combustion chamber and the composite reformer through the No. 4 three-way valve; The air supply system includes a No. 1 fan and a No. 2 fan, a No. 2 solenoid valve is provided between the No. 1 fan and the No. 1 air flow meter, and a No. 4 solenoid valve is provided between the No. 2 fan and the No. 2 air flow meter. The air enters the combustion chamber through the No. 2 fan, the No. 4 solenoid valve, the No. 2 air flow meter and the No. 3 tee, and is mixed with the fuel gas and then burned. The CO2 supply system includes a No. 5 solenoid valve and a No. 3 proton flowmeter, and the No. 3 proton flowmeter is connected to the gas mixing tank through a pipeline.

2. A reversible solid oxide fuel cell system according to claim 1, characterized in that: The combustion chamber is connected to the composite heat exchanger and the composite reformer through an outlet pipeline.

3. A reversible solid oxide fuel cell system according to claim 1, characterized in that: The composite reformer is connected to the gas storage tank after passing through a condenser.

4. A reversible solid oxide fuel cell system according to claim 1, characterized in that: The combustion chamber is respectively provided with a second fuel intake pipeline and a second air intake pipeline.

5. A reversible solid oxide fuel cell system according to claim 1, characterized in that: The water supply system comprises a water tank, and the water tank is connected to the composite reformer and the gas mixing tank through a No. 2 three-way valve.

6. A reversible solid oxide fuel cell system according to claim 1, characterized in that: One end of the composite heat exchanger is connected to the combustion chamber through a tee, and the other end is connected to the No. 2 waste heat utilization device, and the No. 2 waste heat utilization device is connected to the composite reformer through a pipeline.

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