A hydrogen solid oxide fuel cell system

Abstract

The utility model discloses a kind of hydrogen solid oxide fuel cell systems, adopt the system architecture of tail gas combustor and anode tail gas circulation combination, in SOFC system start-up heating stage, fuel gas and air enter tail gas combustor and produce heat by combustion reaction, can be used for preheating cold air and heating electric pile.In system rated power power generation stage, rely on anode tail gas circulation process to pass into electric pile anode entrance again by unreacted fuel gas, so that the effective utilization rate of fuel gas is close to 100%, greatly improve the power generation efficiency of system.And by heat recovery, the circulating fuel gas still keeps humidification state, system does not need to add waterway again, simplify system structure;In addition, pipeline between fan to cathode entrance is air main road, pipeline between fan to air heat exchanger entrance two is air bypass, a way of air bypass is also set in air main road of this system, reach the effect of temperature regulation by flow proportion adjustment of air main road and air bypass.

Description

Technical Field

[0001] This utility model relates to the field of solid oxide fuel cell technology, and more specifically, to a hydrogen solid oxide fuel cell system. Background Technology

[0002] Solid oxide fuel cells (SOFCs), as high-temperature energy conversion devices, have attracted much attention due to their high power generation efficiency and environmental friendliness. In SOFC systems using pure hydrogen as fuel, anode tail gas recirculation technology is commonly used to improve fuel economy. This technology returns unconsumed hydrogen and generated water vapor after the fuel cell reaction to the inlet, thereby significantly improving fuel utilization.

[0003] In addition, achieving stable startup and efficient operation of the system typically involves two key stages: the cold start-up stage and the normal power generation stage. During the start-up stage, the fuel cell stack needs to be preheated to its operating temperature (usually above 700°C) by an external heat source. Existing technologies usually rely on a separate start-up burner to preheat the air and fuel. This process is often decoupled from the anode cycle system in the power generation stage in terms of function and structure, resulting in a complex system structure and low thermal integration.

[0004] Therefore, there is an urgent need in this field for a highly integrated and efficient hydrogen anode cycle system to achieve efficient fuel utilization, thereby comprehensively improving the reliability, adaptability and overall energy efficiency of SOFC systems. Utility Model Content

[0005] This solution provides a hydrogen solid oxide fuel cell system that improves fuel utilization and energy efficiency by coupling the circulation of anode exhaust gas and the preheating of the fuel cell stack within the system.

[0006] To achieve the above objectives, the technical solution provided by this utility model is as follows:

[0007] A hydrogen solid oxide fuel cell system includes a fan, a fuel cell stack, a gas supply device, a gas heat exchanger, and a tail gas burner;

[0008] The fuel cell stack includes an anode and a cathode;

[0009] The outlet of the gas supply device is connected to the inlet one of the gas heat exchanger, the outlet one of the gas heat exchanger is connected to the anode inlet, and the anode outlet is connected to the inlet two of the gas heat exchanger.

[0010] During the system startup and heating phase, the outlet 2 of the gas heat exchanger is connected to the exhaust gas burner; the outlet of the exhaust gas burner is connected to the inlet 2 of the air heat exchanger, and the air heat exchanger is installed on the pipeline at the cathode inlet.

[0011] During the system's power generation operation phase, the outlet of the gas heat exchanger is connected to the outlet of the gas supply device.

[0012] As a further improvement, the fan outlet is connected to the air heat exchanger inlet, the air heat exchanger outlet is connected to the cathode inlet, and the cathode outlet is connected to the exhaust gas burner.

[0013] The fan is also connected to the second inlet of the air heat exchanger.

[0014] As a further improvement, a condenser is also installed on the inlet pipe of the air heat exchanger;

[0015] The outlet 2 of the gas heat exchanger is connected to the inlet 2 of the condenser, the inlet 1 of the condenser is connected to the fan, and the outlet 2 of the condenser is connected to a two-position three-way valve. The two-position three-way valve is connected to the exhaust gas burner and the gas supply device respectively.

[0016] As a further improvement, a gas-liquid separator is also provided between the second outlet of the condenser and the two-position three-way valve.

[0017] As a further improvement, a one-way valve is also provided between the two-position three-way valve and the exhaust gas burner.

[0018] As a further improvement, a gas circuit solenoid valve and a gas circuit mass flow controller are sequentially installed between the outlet of the gas supply device and the inlet of the gas heat exchanger.

[0019] As a further improvement, a hydrogen circulation pump and a safety valve are sequentially installed between the two-position three-way valve and the outlet of the gas circuit mass flow controller.

[0020] As a further improvement, a purge gas supply device is also included, which is connected to the inlet of the gas heat exchanger, and a purge gas path solenoid valve and a purge gas path mass flow controller are sequentially arranged between the purge gas supply device and the inlet of the gas heat exchanger.

[0021] As a further improvement, a condenser is also installed on the inlet pipe of the air heat exchanger; the condenser inlet is connected to the fan.

[0022] As a further improvement, an air main flow meter is installed between the fan and the condenser inlet.

[0023] Furthermore, an air bypass mass flow meter and an air bypass flow regulating valve are sequentially installed between the fan and the second inlet of the air heat exchanger.

[0024] Compared with the prior art, the technical solution provided by this utility model has the following advantages:

[0025] This invention relates to a hydrogen solid oxide fuel cell system that employs a system architecture combining a tail gas burner and anode tail gas recirculation. During the start-up and heating phase of the SOFC system, the fuel gas and air enter the tail gas burner to undergo a combustion reaction and generate heat, which can be used to preheat cold air and heat the fuel cell stack. During the rated power generation phase, the unreacted fuel gas is reintroduced into the anode inlet of the fuel cell stack through the anode tail gas recirculation process, resulting in a near 100% utilization rate of the fuel gas and significantly improving the system's power generation efficiency. Furthermore, through heat recovery, the recirculated fuel gas remains humidified (water content <10%), eliminating the need for additional water circuits and simplifying the system structure. In addition, the pipeline between the fan and the cathode inlet is the main air path, while the pipeline between the fan and the second air heat exchanger inlet is the air bypass. This system also includes an air bypass in the main air path, and temperature control is achieved by adjusting the flow ratio between the main air path and the air bypass. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a hydrogen solid oxide fuel cell system.

[0027] Label Explanation:

[0028] 1. Blower; 201. Purge gas pressure sensor; 202. Gas supply pressure sensor; 203. Air supply pressure sensor; 204. Circulation pressure sensor; 301. Purge gas solenoid valve; 302. Gas supply solenoid valve; 303. Air bypass flow regulating valve; 401. Purge gas mass flow controller; 402. Gas supply mass flow controller; 403. Main air mass flow meter; 404. Bypass mass flow meter;

[0029] 501. Fuel cell anode inlet temperature sensor; 502. Fuel cell anode outlet temperature sensor; 503. Gas heat exchanger heat flow outlet temperature sensor; 504. Fuel cell cathode inlet temperature sensor; 505. Fuel cell cathode outlet temperature sensor; 506. Burner outlet temperature sensor; 507. Air heat exchanger heat flow inlet temperature sensor; 508. Circulating pump inlet temperature sensor.

[0030] 6. Gas heat exchanger; 7. Air heat exchanger; 8. Condenser; 9. Fuel cell stack; 901. Anode; 902. Cathode; 10. Exhaust gas burner; 11. Hydrogen circulation pump; 12. Two-position three-way valve; 13. Check valve; 14. Gas-liquid separator; 15. Safety valve; 16. Gas supply device; 17. Purge gas supply device. Detailed Implementation

[0031] To further understand the content of this utility model, a detailed description of this utility model will be provided in conjunction with the accompanying drawings and embodiments.

[0032] The structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this utility model. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and purposes that this utility model can produce, should still fall within the scope of the technical content disclosed in this utility model.

[0033] Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity of description and are not intended to limit the scope of implementation. Any changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of implementation of this utility model.

[0034] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate for the embodiments of this application described herein.

[0035] like Figure 1 As shown, the hydrogen solid oxide fuel cell system provided in this embodiment includes a fuel cell stack 9, an air heat exchanger 7, a fan 1, a gas supply device 16, a gas heat exchanger 6, and an exhaust gas burner 10.

[0036] The fuel cell stack 9 includes an anode 901 and a cathode 902. Specifically, the fuel cell stack 9 is a solid oxide battery (SOFC) that uses hydrogen as fuel.

[0037] The outlet of the gas supply device 16 is connected to the inlet of the gas heat exchanger 6, the outlet of the gas heat exchanger 6 is connected to the inlet of the anode 901, and the outlet of the anode 901 is connected to the inlet of the gas heat exchanger 6.

[0038] When the system starts up and heats up, the outlet 2 of the gas heat exchanger 6 is connected to the exhaust gas burner 10; the outlet of the exhaust gas burner 10 is connected to the inlet 2 of the air heat exchanger 7, and the air heat exchanger 7 is installed on the pipeline at the inlet of the cathode 902; when the system is generating electricity, the outlet 2 of the gas heat exchanger 6 is connected to the outlet of the gas supply device 16.

[0039] The outlet of fan 1 is connected to the inlet of air heat exchanger 7, the outlet of air heat exchanger 7 is connected to the inlet of cathode 902, and the outlet of cathode 902 is connected to exhaust gas burner 10; fan 1 is also connected to the second inlet of air heat exchanger 7.

[0040] In this scheme, during the system startup and heating phase, hydrogen gas is introduced into the anode 901 side of the fuel cell stack via the gas supply device 16. The hydrogen gas flows out through the anode 901 outlet and enters the exhaust gas burner 10 for combustion. The high-temperature exhaust gas after combustion can be used to preheat the air entering the cathode 902 of the fuel cell stack, while simultaneously heating the fuel cell stack 9. During the system's power generation operation, the high-temperature anode exhaust gas at the anode 901 outlet contains unreacted hydrogen gas. The anode exhaust gas enters the gas heat exchanger 6, which first preheats the newly entering gas gas to the target temperature. Afterward, the anode exhaust gas can be cooled again and recycled back to the outlet of the gas supply device 16 for reuse. In this scheme, the exhaust gas at the anode 901 outlet flows in different directions under different conditions. By coupling the circulation of the anode exhaust gas and the preheating of the fuel cell stack in the system, both fuel utilization and energy utilization efficiency are improved. In addition, the pipeline between the fan and the cathode inlet is the main air pipeline, and the pipeline between the fan and the second inlet of the air heat exchanger is the air bypass pipeline. This system also has an air bypass pipeline in the main air pipeline. The temperature control is achieved by adjusting the flow ratio between the main air pipeline and the air bypass pipeline.

[0041] In a preferred embodiment, the provided hydrogen solid oxide fuel cell system further includes a condenser 8 and a two-position three-way valve 12. The outlet 2 of the gas heat exchanger 6 is connected to the inlet 2 of the condenser 8, and the outlet 2 of the condenser 8 is connected to the two-position three-way valve 12. The two-position three-way valve 12 is connected to the tail gas burner 10 and the gas supply device 16, respectively. By setting the two-position three-way valve 12, the flow direction and flow rate of the anode tail gas can be adjusted at different stages to meet the needs of the system at different stages. The outlet 2 of the gas heat exchanger 6 is connected to the inlet 2 of the condenser 8. During the power generation stage, the anode tail gas still contains a large amount of water vapor, which can be cooled by the condenser 8 to form liquid water. Furthermore, a gas-liquid separator 14 is also provided between the outlet 2 of the condenser 8 and the two-position three-way valve 12. After most of the water vapor condenses into liquid water, it is then separated by the gas-liquid separator 14.

[0042] To improve system safety, a one-way valve 13 is installed between the two-position three-way valve 12 and the exhaust gas burner 10. During the power generation phase, switching the two-position three-way valve 12 allows hydrogen in the anode exhaust gas to circulate to the outlet of the gas supply device 16 and merge with fresh cold gas for reuse. The one-way valve 13 prevents air from flowing back into the hydrogen circulation loop from the exhaust gas burner 10, avoiding safety hazards. This satisfies the requirements for hydrogen humidification and makes the effective utilization rate of hydrogen close to 100%, greatly improving the power generation efficiency of the system.

[0043] A gas supply solenoid valve 302 and a gas flow controller 402 are sequentially installed between the outlet of the gas supply device 16 and the inlet of the gas heat exchanger 6. The gas supply solenoid valve 302 is used to control the on / off state of the gas supply pipeline, and the gas flow controller 402 is used to control the flow rate of the gas supply.

[0044] The other two three-way valves 12 are connected in sequence to the outlet of the gas flow controller 402, where a hydrogen circulation pump 11 and a safety valve 15 are installed. The hydrogen circulation pump 11 provides the power for the recirculation of hydrogen in the anode tail gas. The safety valve 15 can promptly discharge accumulated hydrogen and water in the event of blockage or abnormality in the anode circulation loop, preventing the continuous accumulation of gas without a release outlet.

[0045] Preferably, the provided hydrogen solid oxide fuel cell system further includes a purge gas supply device 17, which is connected to the inlet of the gas heat exchanger 6. A purge gas path solenoid valve 301 and a purge gas path mass flow controller 401 are sequentially arranged between the purge gas supply device 17 and the inlet of the gas heat exchanger 6. Before system startup or after gas supply is cut off in an emergency, the purge gas path solenoid valve 301 is opened, and N2 is introduced through the purge gas supply device 17 to purge residual air or gas in the anode 901 pipeline of the fuel cell stack, thereby improving system safety. The purge gas path solenoid valve 301 is used to control the opening and closing of the purge gas supply pipeline, and the purge gas path mass flow controller 401 is used to control the flow rate of the purge gas supply.

[0046] In a preferred embodiment, the condenser 8 is installed on the inlet pipe of the cathode 902; the inlet of the condenser 8 is connected to the fan 1, the outlet of the condenser 8 is connected to the inlet of the cathode 902, and the outlet of the cathode 902 is connected to the exhaust gas burner 10. An air heat exchanger 7 is also installed between the outlet of the condenser 8 and the inlet of the cathode 902, the inlet of the air heat exchanger 7 is connected to the exhaust gas burner 10, and the outlet of the air heat exchanger 7 is vented. The anode exhaust gas still has a temperature of 200°C after passing through the gas heat exchanger 6, and the residual heat can be recovered through the condenser 8 for preheating the air, thereby achieving further cooling of the anode exhaust gas.

[0047] An air main mass flow meter 403 is installed between the fan 1 and the inlet 1 of the condenser 8. The fan 1 is also connected to the inlet 2 of the air heat exchanger 7, and an air bypass mass flow meter 404 and an air bypass flow regulating valve 303 are sequentially installed between the fan 1 and the inlet 2 of the air heat exchanger 7. The fan controls the air flow rate by adjusting its speed. The air bypass flow regulating valve 303 is used to control the opening and closing of the air bypass supply pipeline. The air bypass mass flow meter 404 is used to measure the flow rate of the bypass air supply. The air main mass flow meter 403 is used to measure the flow rate of the air main supply. In order to control the gas temperature entering the hot side of the air heat exchanger 7, an air bypass cooling air is provided, supplied by the fan 1, and passes through the air bypass mass flow meter 404 and the air bypass flow regulating valve 303 to the area between the outlet of the exhaust gas burner 10 and the hot side inlet (inlet 2) of the air heat exchanger 7. This is used to regulate the gas temperature entering the air heat exchanger 7 and prevent the exhaust gas temperature from being too high and damaging the air heat exchanger 7.

[0048] During the system startup and heating phase, dry air enters the fuel cell cathode 902 via fan 1. The air then exits through the cathode 902 and enters the exhaust gas burner 10 to react with hydrogen. The high-temperature combustion exhaust gas is then passed into the air heat exchanger 7, which heats the air and preheats the air entering the fuel cell to the required temperature. The preheated air is then passed to the inlet of the fuel cell cathode 902 to heat the fuel cell 9, and then exits from the cathode 902, entering the exhaust gas burner 10 for combustion. The combustion exhaust gas is then vented after heat exchange in the air heat exchanger 7.

[0049] During the rated power generation phase of the system, the exhaust gas from the anode 901 of the fuel cell stack enters the condenser 8 after passing through the gas heat exchanger 6. The cold side inlet of the condenser 8 is the cold air entering the cathode 902 of the fuel cell stack, which condenses most of the water vapor in the anode exhaust gas into liquid water through heat exchange.

[0050] All components in the above system are connected by pipelines.

[0051] To facilitate the control of pressure and temperature in different parts of the system, a purge gas pressure sensor 201 is installed on the outlet pipe of the purge gas supply device 17, a gas pressure sensor 202 is installed on the outlet pipe of the gas supply device 16, an air pressure sensor 203 is installed on the outlet pipe of the blower 1, and a circulation pressure sensor 204 is installed on the outlet pipe of the hydrogen circulation pump 11. A fuel cell anode inlet temperature sensor 501 is installed near the anode 901 inlet, a fuel cell anode outlet temperature sensor 502 is installed near the anode 901 outlet, a fuel cell cathode inlet temperature sensor 504 is installed near the cathode 902 inlet, and a fuel cell cathode outlet temperature sensor 505 is installed near the cathode 902 outlet. A fuel cell heat exchanger heat flow outlet temperature sensor 503 is installed on the outlet two pipe of the gas heat exchanger 6, an air heat exchanger heat flow inlet temperature sensor 507 is installed on the inlet two pipe of the air heat exchanger 7, a burner outlet temperature sensor 506 is installed on the outlet pipe of the exhaust gas burner 10, and a circulation pump inlet temperature sensor 508 is installed on the outlet pipe of the hydrogen circulation pump 11.

[0052] To facilitate understanding, the overall operation of this system will be further explained.

[0053] During the system startup and heating phase, the gas supply device 16 introduces hydrogen into the anode 901 of the fuel cell stack, while dry air enters the cathode 902 of the fuel cell stack via the fan 1. A set gas flow rate is introduced, adjusting the flow ratio between the main and bypass air. Combustion occurs in the exhaust gas burner 10, and the high-temperature combustion exhaust gas is introduced into the air heat exchanger 7, which heats the air entering the fuel cell stack and preheats it to the required temperature. The preheated air is then introduced to the inlet of the cathode 902, simultaneously heating the fuel cell stack 9, before being discharged from the cathode 902 and entering the exhaust gas burner 10 for combustion.

[0054] The fuel gas introduced into the system passes through the gas heat exchanger 6 and is then introduced into the anode 901 of the fuel cell stack. There, it is heated by the preheated air at the cathode 902, and then discharged from the anode 901. It is then reintroduced into the gas heat exchanger 6, which heats the heat exchanger and preheats the fuel gas entering the fuel cell stack to the required temperature. The hot-side outlet gas from the gas heat exchanger 6 passes through the condenser 8 and then, via a two-position three-way valve 12, enters the exhaust gas burner 10 for combustion. Through this process, the system's hot zone is heated to the specified temperature.

[0055] During the rated power generation phase of the system, the exhaust gas at the outlet of the anode 901 of the fuel cell stack includes unreacted hydrogen and water vapor produced by the electrochemical reaction. This gas is first preheated to the target temperature by the gas heat exchanger 6 before entering the condenser 8. The cold side inlet of the condenser 8 is the cold air entering the cathode 902 of the fuel cell stack. Through heat exchange, most of the water vapor in the anode exhaust gas is condensed into liquid water, which is then separated by the gas-liquid separator 14. At this time, the two-position three-way valve 12 pumps hydrogen containing a small amount of water vapor (humidified hydrogen) back into the anode inlet of the fuel cell stack via the hydrogen circulation pump 11, where it merges with the fresh cold gas.

[0056] The terms “installation,” “setup,” “equipped with,” and “connection” used herein should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0057] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A hydrogen solid oxide fuel cell system, characterized in that: It includes a fan (1), an electric stack (9), a gas supply unit (16), a gas heat exchanger (6), and a tail gas burner (10); The fuel cell stack (9) includes an anode (901) and a cathode (902); The outlet of the gas supply device (16) is connected to the inlet one of the gas heat exchanger (6), the outlet one of the gas heat exchanger (6) is connected to the inlet of the anode (901), and the outlet of the anode (901) is connected to the inlet two of the gas heat exchanger (6). During the system startup and heating phase, the outlet of the gas heat exchanger (6) is connected to the exhaust gas burner (10); the outlet of the exhaust gas burner (10) is connected to the inlet of the air heat exchanger (7), and the air heat exchanger (7) is installed on the pipeline at the inlet of the cathode (902). During the system's power generation operation phase, the outlet of the gas heat exchanger (6) is connected to the outlet of the gas supply device (16).

2. The hydrogen solid oxide fuel cell system according to claim 1, characterized in that: The outlet of the fan (1) is connected to the inlet of the air heat exchanger (7), the outlet of the air heat exchanger (7) is connected to the inlet of the cathode (902), and the outlet of the cathode (902) is connected to the exhaust gas burner (10). The fan (1) is also connected to the inlet 2 of the air heat exchanger (7).

3. The hydrogen solid oxide fuel cell system according to claim 1 or 2, characterized in that: A condenser (8) is also installed on the inlet pipe of the air heat exchanger (7); The outlet 2 of the gas heat exchanger (6) is connected to the inlet 2 of the condenser (8), and the inlet 1 of the condenser (8) is connected to the fan (1); the outlet 2 of the condenser (8) is connected to a two-position three-way valve (12), and the two-position three-way valve (12) is connected to the tail gas burner (10) and the gas supply device (16) respectively.

4. The hydrogen solid oxide fuel cell system according to claim 3, characterized in that: A gas-liquid separator (14) is also provided between outlet 2 of the condenser (8) and the two-position three-way valve (12).

5. The hydrogen solid oxide fuel cell system according to claim 3, characterized in that: A one-way valve (13) is also provided between the two-position three-way valve (12) and the exhaust gas burner (10).

6. The hydrogen solid oxide fuel cell system according to claim 3, characterized in that: A gas path solenoid valve (302) and a gas path mass flow controller (402) are sequentially installed between the outlet of the gas supply device (16) and the inlet of the gas heat exchanger (6).

7. The hydrogen solid oxide fuel cell system according to claim 6, characterized in that: A hydrogen circulation pump (11) and a safety valve (15) are sequentially installed between the two-position three-way valve (12) and the outlet of the gas circuit mass flow controller (402).

8. The hydrogen solid oxide fuel cell system according to claim 3, characterized in that: It also includes a purge gas supply device (17), which is connected to the inlet of the gas heat exchanger (6), and a purge gas path solenoid valve (301) and a purge gas path mass flow controller (401) are sequentially arranged between the purge gas supply device (17) and the inlet of the gas heat exchanger (6).

9. The hydrogen solid oxide fuel cell system according to claim 2, characterized in that: An air main flow meter (403) is installed between the inlet of the fan (1) and the condenser (8).

10. The hydrogen solid oxide fuel cell system according to claim 9, characterized in that: Furthermore, an air bypass mass flow meter (404) and an air bypass flow regulating valve (303) are sequentially installed between the fan (1) and the inlet 2 of the air heat exchanger (7).

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