Fuel cell efficient thermal management system and method based on liquid fuel reforming

Abstract

The invention discloses a fuel cell efficient thermal management system and method based on liquid fuel reforming, and the system comprises a high-level oil tank which is connected with a high-temperature oil pump through an oil outlet pipeline; the outlet end of the high-temperature oil pump is sequentially connected with an electric heater, a fuel oil heat exchanger, a catalytic combustion inlet temperature sensor, a catalytic combustor, a catalytic combustion outlet temperature sensor, a fuel cell oil way inlet temperature sensor and a high-temperature proton exchange membrane fuel cell; the rear end of the high-temperature proton exchange membrane fuel cell is connected with an oil pipe and a three-way tangential valve; and one end of the three-way tangential valve is connected with an oil outlet pipe of the high-level oil tank, and the other end of the three-way tangential valve is connected with a radiator assembly. According to the system, stable output of the fuel cell system based on liquid fuel reforming is realized; the anode tail gas is treated through the catalytic combustor, the safety and efficiency of the system are improved, and the reliability of the system under various working conditions is improved through combined heat dissipation of the catalytic combustion air pump.

Description

Technical Field

[0001] This invention relates to the field of fuel cell power generation system technology, and more particularly to a high-efficiency thermal management system for fuel cells based on liquid fuel reforming and its operating method. Background Technology

[0002] Fuel cell power generation systems based on liquid fuel reforming produce hydrogen through the reforming of fuels such as hydrocarbons and alcohols. The reformed gas is then fed into a high-temperature proton exchange membrane fuel cell to generate electricity directly. The advantages of this technology include a wide variety of fuels, easy availability, and low characteristic signals. This technology is increasingly becoming a research hotspot.

[0003] The primary function of the thermal management system is to achieve thermal balance between the internal fuel processor and the high-temperature proton exchange membrane fuel cell, as well as between the system and the environment. Thermal management involves both startup and stable operation. During startup, the system is rapidly started up using fuel chemical energy and electrical energy. During stable operation, waste heat generated by the fuel cell (heat transfer oil and anode exhaust gas) is used to preheat the water required by the fuel processor, and excess heat is balanced through a radiator. Therefore, firstly, the thermal management system needs to achieve rapid system startup with minimal power consumption; secondly, under various operating conditions, the thermal management system can recover waste heat and regulate the thermal balance of the reactor and fuel cell, ensuring efficient and stable system operation.

[0004] Existing thermal management systems for high-temperature proton exchange membrane fuel cells suffer from problems such as complex coupling preventing independent operation, a single heat source, and low efficiency. One example, a vehicle-mounted high-temperature fuel cell cold-start system and its operating method (CN105024088A), requires the diesel engine to preheat the fuel cell system before it can start, thus preventing independent operation. Another example, a high-temperature fuel cell thermal management system (CN106532092A), uses electric heating as its heat source, resulting in a single heat source and a cooling device connected in series in the main circuit, leading to heat loss, low efficiency, and slow start-up. A rapid start-up method for high-temperature fuel cells (CN111952639A) requires a lithium battery and uses electric heating to raise the system temperature. However, the lithium battery is large and does not recover waste heat from the fuel cell, resulting in low efficiency. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention discloses a high-efficiency thermal management system for fuel cells based on liquid fuel reforming. This system solves the technical problems of existing thermal management systems, such as complex coupling preventing independent operation, single heat source, and low efficiency. The specific technical solution includes:

[0006] The system includes a high-level fuel tank, which is connected to a high-temperature fuel pump via an oil outlet pipe. The outlet of the high-temperature fuel pump is sequentially connected to an electric heater, a fuel heat exchanger, a catalytic combustion inlet temperature sensor, a catalytic burner, a catalytic combustion outlet temperature sensor, a fuel cell oil circuit inlet temperature sensor, and a high-temperature proton exchange membrane fuel cell. The rear end of the high-temperature proton exchange membrane fuel cell is connected to a three-way tangential valve via an oil pipe. One end of the three-way tangential valve is connected to the oil outlet pipe of the high-level fuel tank, and the other end is connected to a radiator assembly. The outlet of the radiator assembly is connected to the oil outlet pipe of the high-level fuel tank. One end of the fuel heat exchanger is connected to the fuel pump, where the exhaust gas after combustion exchanges heat with heat transfer oil. The fuel heat exchanger is connected to the inlet of a heat recovery heat exchanger via an exhaust gas pipe, and the other inlet of the heat recovery heat exchanger is connected to a water pump. The heat recovery heat exchanger has two outlets: one is a heat recovery exhaust gas discharge pipe, and the other is a heat exchange hot water pipe.

[0007] The catalytic combustor includes a catalytic combustion reactor and a catalytic combustion heat exchanger. The catalytic combustion reactor has two inlet ends, one of which is connected to the anode of a high-temperature proton exchange membrane fuel cell, and the other inlet end is connected to a catalytic combustion air pump. The exhaust gas generated by catalytic combustion exchanges heat with heat transfer oil through a heat recovery heat exchanger.

[0008] The high-level oil tank is located at the highest point of the system, and is designed to withstand a high temperature of 180°C. It is made of stainless steel or aluminum alloy.

[0009] The high-temperature oil pump, catalytic combustion inlet temperature sensor, catalytic combustion outlet temperature sensor, and three-way tangential valve are all heat-resistant to temperatures above 180°C.

[0010] The filling material inside the fuel heat exchanger is methanol, ethanol, gasoline, or diesel.

[0011] The filling material inside the catalytic burner is hydrogen-rich gas.

[0012] The heat recovery heat exchanger is a plate-fin heat exchanger.

[0013] The system's oil lines are made of corrugated metal tubing or braided silicone tubing.

[0014] The heat exchange medium for the fuel oil heat exchange is heat transfer oil.

[0015] A method for operating a high-efficiency thermal management system for a fuel cell based on liquid fuel reforming includes the following steps:

[0016] After the system is filled with oil and vented, it starts up. The inlet end of the three-way tangential valve is connected to the oil outlet of the fuel cell, and the outlet end is connected to the oil outlet pipe of the high-level oil tank. The high-temperature oil pump is turned on to start the startup process.

[0017] System power increase process: When the fuel cell oil circuit inlet temperature sensor rises to 170℃, the system enters the stable operation stage. The electric heater and fuel pump are turned off, external heating is stopped, and the three-way tangential valve is opened to connect the radiator assembly in series with the oil circuit. The cooling fan of the radiator assembly is adjusted to control the temperature of the fuel cell oil circuit inlet temperature sensor to be less than 180℃. At this time, the catalytic burner is still working, and the high-temperature proton exchange membrane fuel cell consumes the remaining hydrogen. If the performance of the high-temperature proton exchange membrane fuel cell degrades as it works for a long time, and the waste heat increases beyond the heat dissipation capacity of the radiator assembly, the air volume of the catalytic combustion gas pump is increased to combine heat dissipation and ensure system thermal balance.

[0018] During startup and operation, the high-temperature exhaust gases from the fuel heat exchanger and catalytic burner converge into the heat recovery heat exchanger, and the water pump is turned on to recover and utilize the heat from the high-temperature exhaust gases.

[0019] Furthermore, the system startup process includes: Method 1: When external electrical energy is sufficient, the electric heater is activated to heat the heat transfer oil, raising its temperature and exchanging heat with the high-temperature proton exchange membrane fuel cell; Method 2: When external electrical energy is insufficient but fuel is sufficient, the fuel pump is activated to burn fuel in the fuel oil heat exchanger, heating the heat transfer oil and exchanging heat with the high-temperature proton exchange membrane fuel cell; Method 3: When both external electrical energy and fuel are sufficient, the electric heater and fuel oil heat exchanger are used simultaneously to heat the heat transfer oil, raising its temperature and exchanging heat with the high-temperature proton exchange membrane fuel cell; Method 4: When the fuel processor produces hydrogen-rich gas, the hydrogen-rich gas is... The gas enters the catalytic burner through the anode outlet of the high-temperature proton exchange membrane fuel cell. The catalytic combustion gas pump is turned on, and the heat generated by catalytic combustion heats the heat transfer oil and exchanges heat with the high-temperature proton exchange membrane fuel cell 11. When the temperature of the oil inlet temperature sensor of the high-temperature proton exchange membrane fuel cell 11 is 120°C, the high-temperature proton exchange membrane fuel cell 11 discharges. The hydrogen-rich gas generated by the fuel processor is introduced into the anode of the fuel cell. The high-temperature proton exchange membrane fuel cell 11 discharges and consumes hydrogen. The remaining anode tail gas continues to undergo catalytic combustion to provide heat to heat the heat transfer oil and exchange heat with the fuel cell, completing the rapid start-up.

[0020] By employing the above-mentioned technical solutions, this invention provides a high-efficiency thermal management system for fuel cells based on liquid fuel reforming. During the startup phase, the system utilizes a "small circulation" oil path to reduce heating of the radiator assembly, a component for system regulation and balancing, thereby minimizing heat loss. Furthermore, it can optimize heating modes such as electric heating, fuel combustion heating, and catalytic combustion heating based on external energy reserves, forming multiple combinations to achieve the beneficial effect of rapid startup of the liquid fuel reforming fuel cell system. During stable operation, the system utilizes a "large circulation" oil path, incorporating a heat regulation radiator assembly to rapidly regulate fuel cell temperature, reducing temperature fluctuations and achieving stable output for the liquid fuel reforming fuel cell system. The catalytic burner treats the anode exhaust gas, improving system safety and efficiency. Combined cooling via a catalytic combustion gas pump enhances system reliability under various operating conditions. Finally, the system recovers heat from the high-temperature exhaust gas through a heat recovery heat exchanger, further improving system efficiency while simultaneously enabling combined heat and power (CHP) functionality for the liquid fuel reforming fuel cell system, thus increasing the overall energy conversion efficiency of the system. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a block diagram of the efficient thermal management system for fuel cells based on liquid fuel reforming.

[0023] In the diagram: 1. High-level fuel tank; 2. High-temperature fuel pump; 3. Electric heater; 4. Fuel heat exchanger; 5. Catalytic combustion inlet temperature sensor; 6. Catalytic burner; 7. Water pump; 8. Heat recovery heat exchanger; 9. Catalytic combustion outlet temperature sensor; 10. Fuel cell oil circuit inlet temperature sensor; 11. High-temperature proton exchange membrane fuel cell; 12. Three-way tangential valve; 13. Catalytic combustion air pump; 14. Fuel pump; 15. Radiator assembly. Detailed Implementation

[0024] To make the technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention:

[0025] like Figure 1The diagram illustrates a high-efficiency thermal management system for a fuel cell based on liquid fuel reforming. It includes a high-level fuel tank 1, which is connected to a high-temperature fuel pump 2 via an oil outlet pipe. The outlet of the high-temperature fuel pump 2 is sequentially connected to an electric heater 3, a fuel heat exchanger 4, a catalytic combustion inlet temperature sensor 5, a catalytic burner 6, a catalytic combustion outlet temperature sensor 9, a fuel cell oil circuit inlet temperature sensor 10, and a high-temperature proton exchange membrane fuel cell 11. The rear end of the high-temperature proton exchange membrane fuel cell 11 is connected to a three-way tangential valve 12 via an oil pipe. One end of the three-way tangential valve 12 is connected to the oil outlet pipe of the high-level fuel tank 1, and the other end is connected to a radiator assembly 15. The outlet of the radiator assembly 15 is connected to the oil outlet pipe of the high-level fuel tank 1. The fuel heat exchanger 4 is connected to the fuel pump 14 at one end. The exhaust gas after combustion exchanges heat with the heat transfer oil in the heat exchanger and is connected to the heat recovery heat exchanger 8 through the exhaust gas pipe. The catalytic combustor 6 includes a catalytic combustion reactor and a catalytic combustion heat exchanger. The catalytic combustion reactor has two inlet ends. One inlet end is connected to the anode exhaust gas end of the high-temperature proton exchange membrane fuel cell 11, and the other inlet end is connected to the catalytic combustion air pump 13. The exhaust gas generated by catalytic combustion exchanges heat with the heat transfer oil through the heat recovery heat exchanger 8. The exhaust gas after heat exchange is connected to the heat recovery heat exchanger 8 through the exhaust gas pipe. The heat recovery heat exchanger 8 has two inlet ends. One inlet end is connected to the fuel heat exchanger 4 and its function is to heat the exhaust gas after heat exchange in the catalytic combustor 6. The other inlet end is connected to the water pump 7. It has two outlet ends. One outlet end is connected to the exhaust gas discharge pipe after heat recovery, and the other outlet end is connected to the hot water pipe after heat exchange.

[0026] Furthermore, the high-level oil tank 1 needs to be located at the highest point of the system for easy venting, and needs to withstand high temperatures of 180°C. The material can be stainless steel or aluminum alloy.

[0027] Furthermore, the high-temperature oil pump 2, the catalytic combustion inlet temperature sensor 5, the catalytic combustion outlet temperature sensor 9, and the three-way tangential valve 12 can all withstand temperatures above 180°C.

[0028] Optionally, the electric heater 3 may be a PTC electric heater.

[0029] Optionally, the fuel heat exchanger 4 can burn fuels such as methanol, ethanol, gasoline, and diesel.

[0030] Optionally, the catalytic burner 6 can burn hydrogen-rich gas.

[0031] Optionally, the heat recovery heat exchanger 8 can be a plate-fin heat exchanger.

[0032] Optionally, the oil pipeline can be a metal corrugated pipe, a braided silicone tube, etc.

[0033] Optionally, the exhaust gas and hot water pipes can be metal corrugated pipes, braided silicone pipes, etc.

[0034] Optionally, the heat exchange medium is heat transfer oil.

[0035] The working method of a high-efficiency thermal management system for fuel cells based on liquid fuel reforming disclosed in this invention is as follows:

[0036] The system can only be started after the system is filled with oil and vented. There are multiple quick start-up methods during the start-up phase. The inlet end of the three-way tangential valve 12 is connected to the oil outlet of the high-temperature proton exchange membrane fuel cell 11, and the outlet end is connected to the oil outlet pipe of the high-level oil tank 1. The high-temperature oil pump 2 is turned on to start the system. Method 1: When external power is sufficient, including mains power and secondary batteries, the electric heater 3 can be turned on to heat the heat transfer oil and exchange heat with the high-temperature proton exchange membrane fuel cell 11. Method 2: When external power is insufficient but fuel is sufficient, the fuel pump 14 can be turned on to heat the heat transfer oil by burning fuel in the fuel oil heat exchanger 4 and exchanging heat with the high-temperature proton exchange membrane fuel cell 11. Method 3: When both external power and fuel are sufficient, the electric heater 3 and the fuel oil heat exchanger 4 can be used simultaneously to heat the heat transfer oil and exchange heat with the high-temperature proton exchange membrane fuel cell 11. Method 4: When the fuel processor produces hydrogen-rich gas, the hydrogen-rich gas enters the catalytic combustor 6 through the anode outlet of the fuel cell, and the catalytic combustion gas pump 13 is turned on to perform catalytic combustion to generate heat to heat the heat transfer oil and exchange heat with the high-temperature proton exchange membrane fuel cell 11. When the temperature of the fuel cell oil inlet temperature sensor 10 is 120°C, the high-temperature proton exchange membrane fuel cell 11 can discharge. The hydrogen-rich gas generated by the fuel processor is introduced into the anode of the fuel cell. The high-temperature proton exchange membrane fuel cell 11 discharges and consumes hydrogen. The remaining anode tail gas can continue to undergo catalytic combustion to provide heat to heat the heat transfer oil and exchange heat with the high-temperature proton exchange membrane fuel cell 11, thus completing the rapid start-up.

[0037] As the system increases its power, when the fuel cell oil inlet temperature sensor 10 rises to 170°C, the system enters a stable operating phase. The electric heater 3, fuel pump 14, etc., are shut off to stop external heating. The three-way tangential valve 12 is opened to connect the radiator assembly 15 in series with the oil circuit, achieving a "large circulation." The cooling fan of the radiator assembly 15 is adjusted to ensure the temperature of the fuel cell oil inlet sensor 10 is below 180°C. At this time, the catalytic burner 6 continues to operate to process the remaining hydrogen after the high-temperature proton exchange membrane fuel cell 11 is consumed. If the performance of the high-temperature proton exchange membrane fuel cell 11 deteriorates over time, and the waste heat increases beyond the heat dissipation capacity of the radiator assembly 15, the airflow of the catalytic combustion pump 13 can be increased for combined heat dissipation to ensure system thermal balance.

[0038] During startup and operation, the high-temperature exhaust gases from the fuel heat exchanger 4 and the catalytic burner 6 converge into the heat recovery heat exchanger 8. The water pump 7 is turned on, which can recover the heat of the high-temperature exhaust gases to heat water. Part of the heated water can participate in the reforming of hydrogen by the fuel processor to improve efficiency, and the other part can realize the function of supplying hot water to the fuel cell system based on liquid fuel reforming, thereby improving the overall system efficiency.

[0039] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-efficiency thermal management system for fuel cells based on liquid fuel reforming, characterized in that... include: The system includes a high-level oil tank (1), which is connected to a high-temperature oil pump (2) via an oil outlet pipe. The outlet end of the high-temperature oil pump (2) is sequentially connected to an electric heater (3), a fuel heat exchanger (4), a catalytic combustion inlet temperature sensor (5), a catalytic burner (6), a catalytic combustion outlet temperature sensor (9), a fuel cell oil circuit inlet temperature sensor (10), and a high-temperature proton exchange membrane fuel cell (11). The rear end of the high-temperature proton exchange membrane fuel cell (11) is connected to a three-way tangential valve (12) via an oil pipe. One end of the three-way tangential valve (12) is connected to the oil outlet pipe of the high-level oil tank (1). The other end is connected to the radiator assembly (15); the outlet end of the radiator assembly (15) is connected to the oil outlet pipe of the high-level oil tank (1); one end of the fuel heat exchanger (4) is connected to the fuel pump (14); the exhaust gas after combustion exchanges heat with the heat transfer oil in the fuel heat exchanger (4); the fuel heat exchanger (4) is connected to the inlet end of the heat recovery heat exchanger (8) through the exhaust gas pipe; the other inlet end of the heat recovery heat exchanger (8) is connected to the water pump (7); the heat recovery heat exchanger (8) includes two outlet ends, one of which is the exhaust gas discharge pipe after heat recovery, and the other outlet end is the hot water pipe after heat exchange. The catalytic burner (6) includes a catalytic combustion reactor and a catalytic combustion heat exchanger. The catalytic combustion reactor includes two inlet ends, one of which is connected to the anode of the high-temperature proton exchange membrane fuel cell (11), and the other inlet end is connected to the catalytic combustion air pump (13). The exhaust gas generated by catalytic combustion exchanges heat with the heat transfer oil through the heat recovery heat exchanger (8).

2. The high-efficiency thermal management system for fuel cells based on liquid fuel reforming according to claim 1, characterized in that: The high-level oil tank (1) is located at the highest point of the system, and is designed to withstand a high temperature of 180°C. It is made of stainless steel or aluminum alloy.

3. The high-efficiency thermal management system for fuel cells based on liquid fuel reforming according to claim 1, characterized in that: The high-temperature oil pump (2), catalytic combustion inlet temperature sensor (5), catalytic combustion outlet temperature sensor (9), and three-way tangential valve (12) are all heat-resistant to temperatures above 180°C.

4. The high-efficiency thermal management system for fuel cells based on liquid fuel reforming according to claim 1, characterized in that: The filling material inside the fuel heat exchanger (4) is methanol, ethanol, gasoline or diesel.

5. A high-efficiency thermal management system for fuel cells based on liquid fuel reforming according to claim 1, characterized in that: The filling material inside the catalytic burner (6) is hydrogen-rich gas.

6. The high-efficiency thermal management system for fuel cells based on liquid fuel reforming according to claim 1, characterized in that: The heat recovery heat exchanger (8) is a plate-fin heat exchanger.

7. A high-efficiency thermal management system for fuel cells based on liquid fuel reforming according to claim 1, characterized in that: The system's oil lines are made of corrugated metal tubing or braided silicone tubing.

8. A high-efficiency thermal management system for fuel cells based on liquid fuel reforming according to claim 1, characterized in that: The heat exchange medium of the fuel oil heat exchanger (4) is heat transfer oil.

9. A method for operating a high-efficiency thermal management system for a fuel cell based on liquid fuel reforming as described in any one of claims 1-8, characterized in that: After the system is filled with oil and vented, it starts up. The inlet end of the three-way tangential valve (12) is connected to the oil outlet of the fuel cell (11), and the outlet end is connected to the oil outlet pipe of the high-level oil tank (1). The high-temperature oil pump (2) is turned on to start the process. System power increase process: When the fuel cell oil circuit inlet temperature sensor (10) rises to 170°C, the system enters the stable operation stage. The electric heater (3) and fuel pump (14) are turned off, external heating is stopped, and the three-way tangential valve (12) is opened to connect the radiator assembly (15) in series to the oil circuit. The cooling fan of the radiator assembly (15) is adjusted to control the temperature of the fuel cell oil circuit inlet temperature sensor (10) to be less than 180°C. At this time, the catalytic burner (6) is still working, and the high-temperature proton exchange membrane fuel cell (11) consumes the remaining hydrogen. If the performance of the high-temperature proton exchange membrane fuel cell (11) deteriorates after working for a long time, and the waste heat increases beyond the heat dissipation capacity of the radiator assembly (15), the air volume of the catalytic combustion gas pump (13) is increased to combine heat dissipation and ensure the thermal balance of the system. During startup and operation, the high-temperature exhaust gases from the fuel heat exchanger (4) and the catalytic burner (6) are combined into the heat recovery heat exchanger (8), and the water pump (7) is turned on to recover and utilize the heat of the high-temperature exhaust gases.

10. The working method of the high-efficiency thermal management system for fuel cells based on liquid fuel reforming according to claim 9, characterized in that: The startup process of this system includes: Method 1: When there is sufficient external power, the electric heater (3) is turned on to heat the heat transfer oil and exchange heat with the fuel cell (11); Method 2: When there is insufficient external power but sufficient fuel, the fuel pump (14) is turned on to heat the heat transfer oil by burning fuel in the fuel heat exchanger (4) and exchanging heat with the fuel cell (11); Method 3: When both external power and fuel are sufficient, the electric heater (3) and the fuel heat exchanger (4) are used simultaneously to heat the heat transfer oil and exchange heat with the fuel cell (11); Method 4: When the fuel processor produces hydrogen-rich gas, the hydrogen-rich gas... The fuel enters the catalytic burner (6) through the anode outlet of the fuel cell. The catalytic combustion gas pump (13) is turned on to generate heat for catalytic combustion, which heats the heat transfer oil and exchanges heat with the fuel cell (11). When the temperature of the fuel cell oil inlet temperature sensor (10) is 120°C, the high-temperature proton exchange membrane fuel cell (11) discharges. The hydrogen-rich gas generated by the fuel processor is introduced into the anode of the fuel cell. The high-temperature proton exchange membrane fuel cell (11) discharges and consumes hydrogen. The remaining anode tail gas continues to catalytically combust to provide heat for heating the heat transfer oil and exchanging heat with the fuel cell (11), thus completing the rapid start-up.

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