Medium-temperature fuel cell

Abstract

The invention relates to the field of fuel cells, in particular to a medium-temperature fuel cell. Comprising a reformer, an electric pile, a first air supply path, a methanol water combustion supply path, a methanol water reaction supply path, a medium circulation water path and a second air path, the first air supply path provides oxygen for combustion of a combustion area of the reformer, and the methanol water combustion supply path provides fuel for combustion of the combustion area of the reformer; heat generated during combustion in the combustion area of the reformer is exchanged to the medium circulating water path through the first plate heat exchanger, the heat at the moment enters the galvanic pile through the medium circulating water path to heat the galvanic pile, and after the galvanic pile reaches the starting temperature, the methanol-water reaction supply path supplies methanol water, so that hydrogen is generated through reaction in the reaction area of the reformer and conveyed to the galvanic pile; and the second air path provides oxygen for the galvanic pile to ensure that the galvanic pile can react to generate power, and effective starting of the reformer and the galvanic pile can be realized through the system.

Description

Technical Field

[0001] This invention relates to the field of fuel cells, and more particularly to a medium-temperature fuel cell. Background Technology

[0002] Currently, fuel cells, as a highly efficient and environmentally friendly energy conversion device, are gradually gaining attention. Among them, intermediate-temperature fuel cell systems, with their unique operating characteristics and application potential, have become the focus of industry attention. Intermediate-temperature fuel cell systems operate at temperatures between 140℃ and 170℃, a range that ensures efficient electrochemical reactions while avoiding the material challenges posed by high temperatures. Compared to traditional low-temperature fuel cells, intermediate-temperature systems exhibit higher CO (carbon monoxide) tolerance, allowing reformed gas to be directly fed into the stack for discharge without a cumbersome purification process, greatly simplifying the system structure and reducing operating costs. However, the design and implementation of intermediate-temperature fuel cell systems also face numerous challenges. Ensuring the effective start-up of the reformer and the intermediate-temperature stack is one of them. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a medium-temperature fuel cell and to solve the problem of how to ensure the effective start-up of the reformer and the medium-temperature fuel cell stack.

[0004] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A medium-temperature fuel cell includes a reformer, a stack, a first air supply path, a methanol-water combustion supply path, a methanol-water reaction supply path, a medium circulation water path, and a second air path. The first air supply path and the methanol-water combustion supply path are both connected to the combustion zone of the reformer. The methanol-water reaction supply path is connected to the reaction zone of the reformer. The reaction zone of the reformer is connected to the stack via a hydrogen path. The medium circulation water path is heat-exchange connected to the stack. The medium circulation water path is heat-exchange connected to the reforming exhaust gas path via a first plate heat exchanger. The second air path is connected to the stack.

[0005] Furthermore, the hydrogen supply path of the reformer and the methanol-water reaction supply path are connected by a second plate heat exchanger.

[0006] Furthermore, the exhaust gas from the fuel cell stack is connected to the combustion zone of the reformer.

[0007] Furthermore, the medium circulation water path at the fuel cell outlet is connected to the second air path via a third plate heat exchanger.

[0008] Furthermore, the first air supply path includes a first air filter, a first fan, a first flow meter, and an air preheater connected in sequence by pipelines, and the air preheater is connected to the combustion zone of the reformer.

[0009] Furthermore, the methanol-water combustion supply path includes a methanol-water supply pump, a first methanol-water tank, a first filter, a combustion pump, a first check valve, and a vaporization heater connected in sequence via pipelines. The vaporization heater is connected to the combustion zone of the reformer.

[0010] Furthermore, the methanol-water reaction supply path includes a second methanol-water tank, a second filter, a reforming pump, and a second check valve connected in sequence by pipelines, with the second check valve connected to the reaction zone of the reformer.

[0011] Furthermore, the medium circulation water circuit includes an expansion tank, an air-cooled condenser, a circulation pump, and a circulation water heater, and the expansion tank, air-cooled condenser, circulation pump, circulation water heater, and fuel cell stack are sequentially connected by pipelines to form the circulation water circuit.

[0012] Furthermore, the second air path includes a second air filter, a second fan, and a second flow meter connected in sequence by pipelines, and the second flow meter is connected to the fuel cell stack.

[0013] This invention provides a medium-temperature fuel cell, comprising a reformer, a stack, a first air supply path, a methanol-water combustion supply path, a methanol-water reaction supply path, a medium circulation water path, and a second air path. The first air supply path and the methanol-water combustion supply path are both connected to the combustion zone of the reformer. The methanol-water reaction supply path is connected to the reaction zone of the reformer. The reaction zone of the reformer is connected to the stack via a hydrogen path. The medium circulation water path is heat-exchange connected to the stack. The medium circulation water path is heat-exchange connected to the reforming exhaust gas path via a first plate heat exchanger. The second air path is connected to the stack. In this way, the first air supply path provides oxygen for combustion in the reformer combustion zone, while the methanol-water combustion supply path provides fuel for combustion in the reformer combustion zone. The heat generated during combustion in the reformer combustion zone is transferred to the medium circulation water path via the first plate heat exchanger. At this time, the heat enters the fuel cell stack through the medium circulation water path to heat the fuel cell stack. After the fuel cell stack reaches the start-up temperature, the methanol-water reaction supply path supplies methanol-water to enable the reformer reaction zone to react and generate hydrogen, which is then transported to the fuel cell stack. The second air path provides oxygen to the fuel cell stack to ensure that the fuel cell stack can react and generate electricity. Through this system, the reformer and fuel cell stack can be effectively started up. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a medium-temperature fuel cell system according to the present invention.

[0015] The attached diagram lists the components represented by each number as follows:

[0016] 1. Reformer; 2. Fuel cell stack; 3. First plate heat exchanger; 4. Second plate heat exchanger; 5. Third plate heat exchanger; 6. First air filter; 7. First fan; 8. First flow meter; 9. Air preheater; 10. Methanol-water supply pump; 11. First methanol-water tank; 12. First filter; 13. Combustion pump; 14. First check valve; 15. Vaporization heater; 16. Second methanol-water tank; 17. Second filter; 18. Reformer pump; 19. Second check valve; 20. Expansion tank; 21. Air-cooled condenser; 22. Circulation pump; 23. Circulating water heater; 24. Second air filter; 25. Second fan; 26. Second flow meter. Detailed Implementation

[0017] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0018] In the description of this invention, it should be understood that the terms "upper", "lower", "center", "inner", "outer", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0019] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0020] like Figure 1As shown, the present invention provides a medium-temperature fuel cell, which includes a reformer 1, a fuel cell stack 2, a first air supply path, a methanol-water combustion supply path, a methanol-water reaction supply path, a medium circulation water path, and a second air path. The first air supply path and the methanol-water combustion supply path are both connected to the combustion zone of the reformer 1. The methanol-water reaction supply path is connected to the reaction zone of the reformer 1. The reaction zone of the reformer 1 is connected to the fuel cell stack 2 through a hydrogen path. The medium circulation water path is heat-exchange connected to the fuel cell stack 2. The medium circulation water path is heat-exchange connected to the reforming exhaust gas path through a first plate heat exchanger 3. The second air path is connected to the fuel cell stack 2. In this way, the first air supply path provides oxygen for combustion in the combustion zone of reformer 1, while the methanol-water combustion supply path provides fuel for combustion in the combustion zone of reformer 1. The heat generated during combustion in the combustion zone of reformer 1 is transferred to the medium circulation water path by the first plate heat exchanger 3. At this time, the heat enters the fuel cell stack 2 through the medium circulation water path to heat the fuel cell stack 2. After the fuel cell stack 2 reaches the start-up temperature, the methanol-water reaction supply path supplies methanol-water so that the reaction zone of reformer 1 can react to generate hydrogen, which is then transported to the fuel cell stack 2. The second air path provides oxygen to the fuel cell stack 2 to ensure that the fuel cell stack 2 can react and generate electricity. Through this system, the reformer 1 and the fuel cell stack 2 can be effectively started up.

[0021] The medium-temperature fuel cell of the present invention, such as Figure 1 As shown, based on the previously described technical solution, the hydrogen path of the reformer 1 and the methanol-water reaction supply path can also be connected via a second plate heat exchanger 4. In this way, the second plate heat exchanger 4 is configured between the hydrogen path and the methanol-water reaction supply path of the reformer 1, achieving efficient heat transfer and utilization. During the exothermic reaction in the reformer 1, the abundant thermal energy carried by the hydrogen, if directly transferred to the fuel cell stack 2 without utilization, would undoubtedly be a huge waste of energy. Therefore, a second plate heat exchanger 4 is added to the path of hydrogen to the fuel cell stack 2, making it a bridge between the hydrogen and the methanol-water reaction supply path. The heat released by the hydrogen path is fully absorbed by the methanol-water reaction supply path. This thermal energy conversion process not only avoids unnecessary energy loss but also promotes the atomization effect of the methanol-water. The heated methanol-water, in a finer atomized state, can more deeply contact the catalyst in the reaction zone of the reformer 1, thereby greatly improving the efficiency and completeness of the reforming reaction. This not only enables the recycling of energy, but also promotes the optimization and upgrading of the reaction process.

[0022] The medium-temperature fuel cell of the present invention, such as Figure 1As shown, based on the previously described technical solution, another option is to connect the exhaust gas from the fuel cell stack 2 after the reaction to the combustion zone of the reformer 1. In this way, during the power generation process of the fuel cell stack 2, due to the limited efficiency of hydrogen combustion, approximately 20% hydrogen often remains in the exhaust gas after the reaction. If this exhaust gas is allowed to be directly emitted, it will not only have adverse environmental impacts but may also pose safety hazards due to excessively high hydrogen concentrations, threatening safe production in the work area. Even more regrettably, these underutilized hydrogen resources will be wasted. Therefore, we have adopted a design that connects the exhaust gas from the fuel cell stack 2 to the combustion zone of the reformer 1. This design allows the hydrogen in the exhaust gas to be reused as a combustion energy source, improving overall energy utilization efficiency and effectively reducing environmental pollutant emissions, achieving the goal of green production. Specifically, the hydrogen in the exhaust gas is further burned in the combustion zone of the reformer 1, converting it into heat energy for system use. This process not only solves the environmental and safety problems caused by direct exhaust gas emissions but also achieves a win-win situation for both economic and environmental benefits through energy recovery and reuse.

[0023] The medium-temperature fuel cell of the present invention, such as Figure 1 As shown, based on the previously described technical solution, the medium circulation water path exiting the fuel cell stack 2 can also be connected to the second air path via a third plate heat exchanger 5. In this way, during the continuous and stable operation of the fuel cell stack 2, a large amount of heat energy is generated inside, which is efficiently exchanged through the medium circulation water path. As heat accumulates, the temperature of the circulating water in the medium circulation water path gradually increases. Simultaneously, the temperature of the second air path, as a key channel for supplying air to the fuel cell stack 2, directly affects the efficiency of the chemical reaction between hydrogen and oxygen in the air. To optimize this process, this design connects the medium circulation water path exiting the fuel cell stack 2 to the second air path via a third plate heat exchanger 5. Utilizing the heat exchange capacity of the third plate heat exchanger 5, the heat abundant in the medium circulation water path can be directly transferred to the air in the second air path. This not only increases the temperature of the air before entering the fuel cell stack 2, helping to improve the reaction rate and efficiency of hydrogen and oxygen, but also achieves effective energy recovery and reuse. Furthermore, this heat exchange process lowers the temperature of the circulating water in the medium circulation path, thereby reducing the burden on subsequent cooling treatment of the circulating water. This not only helps extend the service life of the circulating water system but also improves the overall system's energy efficiency ratio, achieving the goals of energy conservation and emission reduction.

[0024] The medium-temperature fuel cell of the present invention, such as Figure 1As shown, based on the previously described technical solution, the first air supply path can also be: the first air supply path includes a first air filter 6, a first fan 7, a first flow meter 8, and an air preheater 9 connected in sequence by pipelines. The air preheater 9 is connected to the combustion zone of the reformer 1. Thus, when the first air supply path supplies air to the combustion zone of the reformer 1, the first air supply path begins at the first air filter 6, whose primary function is to purify the air entering the system, effectively removing particulate impurities and protecting downstream equipment, especially the first fan 7, from wear, thereby extending the overall system's service life. Subsequently, the pre-purified air is sent to the first fan 7, which, as a power source, drives the air to flow along a preset path, ensuring a smooth and efficient air supply process. During the air flow, the first flow meter 8 can measure and record the air supply speed in real time and accurately. This data is not only important feedback on the system's operating status but also a key basis for achieving automated control. Based on feedback from the flow meter, the control system can flexibly adjust the output power of the first fan 7 to ensure a dynamic balance between the air supply and the actual demand of the reformer 1 combustion zone. This avoids resource waste and ensures stable and efficient combustion. Finally, the air is sent to the air preheater 9 for heating. The air preheater 9 raises the air temperature to the appropriate range required by the reformer 1 combustion zone. This significantly improves combustion efficiency, reduces incomplete combustion caused by low temperatures, and thus optimizes the overall system performance.

[0025] The medium-temperature fuel cell of the present invention, such as Figure 1As shown, based on the previously described technical solution, the methanol-water combustion supply path can also be as follows: The methanol-water combustion supply path includes a methanol-water supply pump 10, a first methanol-water tank 11, a first filter 12, a combustion pump 13, a first check valve 14, and a vaporization heater 15 connected in sequence via pipelines. The vaporization heater 15 is connected to the combustion zone of the reformer 1. In this way, the methanol-water combustion supply path ensures that methanol-water can be safely and efficiently supplied to the combustion zone of the reformer 1. This path begins with the methanol-water supply pump 10, which is responsible for drawing methanol-water from an external source or storage device and delivering it to the first methanol-water tank 11 for storage. Here, the methanol-water is temporarily buffered for a stable subsequent supply. The methanol-water in the first methanol-water tank 11 flows through a pipeline to the first filter 12. This filter effectively removes impurities and particulate matter from the methanol-water, ensuring that the methanol-water supplied to the combustion zone is pure and uncontaminated. The improved quality of the filtered methanol-water helps extend the service life of the entire system and improves combustion efficiency. The filtered methanol-water then enters the combustion pump 13. Before flowing into the vaporization heater 15, the methanol-water mixture passes through a first check valve 14. This check valve prevents backflow of the methanol-water mixture during its flow, ensuring the system's unidirectional flow and safety. If backflow occurs, the check valve closes quickly, cutting off the flow path of the methanol-water mixture and preventing damage to the entire system. The methanol-water mixture then enters the vaporization heater 15, where it is heated by an external heat source (such as high-temperature flue gas or electric heating), causing it to change from a liquid to a gaseous state. The vaporized methanol-water mixture has a higher calorific value and better combustion performance, allowing it to mix more thoroughly with the air in the reformer 1's combustion zone and burn, generating a large amount of heat energy for the system's use.

[0026] The medium-temperature fuel cell of the present invention, such as Figure 1As shown, based on the previously described technical solution, the methanol-water reaction supply path can also be as follows: A second methanol-water tank 16, a second filter 17, a reforming pump 18, and a second check valve 19 are connected in sequence via pipelines. The second check valve 19 is connected to the reaction zone of the reformer 1. In this way, the methanol-water solution is stored in the second methanol-water tank 16, which not only serves as a storage container but also ensures the stability and purity of the solution before delivery. Subsequently, the solution enters the second filter 17 through pipelines. This filter uses a high-efficiency filter medium, which can effectively remove impurities, particulate matter, and other adverse factors from the solution, ensuring that the quality of the methanol-water solution entering subsequent stages meets the standards. The filtered methanol-water solution is driven forward by the reforming pump 18 under pressure. The reforming pump 18, as a power source, needs to be precisely calculated according to system requirements to ensure that the methanol-water solution is stably delivered to the reaction zone of the reformer 1 under appropriate pressure and flow rate. To prevent the backflow that may occur during the reaction from affecting the system, the second check valve 19 can close quickly when backflow is detected, thereby protecting the normal operation of the reaction zone of the reformer 1 and avoiding potential safety hazards and performance degradation.

[0027] The medium-temperature fuel cell of the present invention, such as Figure 1 As shown, based on the previously described technical solution, the medium circulation water circuit can also be: An expansion tank 20, an air-cooled condenser 21, a circulation pump 22, and a circulation water heater 23 are connected sequentially via pipelines to form the circulation water circuit. In this way, the circulating water first enters the expansion tank 20, which regulates and stabilizes the system pressure, ensuring the smooth operation of the entire circulation process. Subsequently, the water flows through pipelines into the air-cooled condenser 21, where the heat in the circulating water is dissipated to the external environment using the principle of air convection, achieving effective cooling. Next, the cooled circulating water is powerfully driven by the circulation pump 22, continuing to flow along the pipeline. The circulation pump 22 serves as the power source for the entire circulation system; under its action, the circulating water is transported to the circulation water heater 23. Here, according to system requirements, the circulating water is heated by a heating device to meet the temperature requirements under different operating conditions. Finally, circulating water is introduced into fuel cell stack 2 to provide necessary cooling and temperature control for its operation. Simultaneously, the heat generated during operation of fuel cell stack 2 is also carried away by the circulating water, thus maintaining stable operation of fuel cell stack 2.

[0028] One point to note here is that when fuel cell stack 2 is started, the temperature is low, so it needs to be heated up first for startup. At this time, the fan of the air-cooled condenser 21 is turned off, and the circulating water heater 23 heats the circulating water. After fuel cell stack 2 is running stably, the circulating water heater 23 is turned off, the fan of the air-cooled condenser 21 is turned on, and the medium circulating water circuit only plays the role of heat dissipation and cooling.

[0029] The medium-temperature fuel cell of the present invention, such as Figure 1 As shown, based on the previously described technical solution, the second air path can also be: a second air filter 24, a second fan 25, and a second flow meter 26 connected in sequence via pipelines, with the second flow meter 26 connected to the fuel cell stack 2. In this way, the second air filter 24 purifies the incoming air, removing dust, particles, and other impurities to ensure the quality of the air entering the fuel cell stack 2. The purified air is drawn in and pressurized by the second fan 25, providing sufficient power for the airflow within the fuel cell stack 2. The second flow meter 26 precisely measures and controls the airflow, ensuring that air enters the fuel cell stack 2 at a set flow rate to react with the fuel and generate electricity.

[0030] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A medium-temperature fuel cell, characterized in that: It includes a reformer (1), a fuel cell stack (2), a first air supply path, a methanol-water combustion supply path, a methanol-water reaction supply path, a medium circulation water path, and a second air path. The first air supply path and the methanol-water combustion supply path are both connected to the combustion zone of the reformer (1). The methanol-water reaction supply path is connected to the reaction zone of the reformer (1). The reaction zone of the reformer (1) is connected to the fuel cell stack (2) through a hydrogen path. The medium circulation water path is heat-exchange connected to the fuel cell stack (2). The medium circulation water path is heat-exchange connected to the tail gas path of the reformer through a first plate heat exchanger (3). The second air path is connected to the fuel cell stack (2).

2. The intermediate-temperature fuel cell according to claim 1, characterized in that: The hydrogen path of the reformer (1) and the methanol-water reaction supply path are connected by a second plate heat exchanger (4).

3. The intermediate-temperature fuel cell according to claim 1, characterized in that: The exhaust gas from the fuel cell stack (2) after the reaction is connected to the combustion zone of the reformer (1).

4. The intermediate-temperature fuel cell according to claim 1, characterized in that: The medium circulation water path outlet stack (2) is connected to the second air path through a third plate heat exchanger (5).

5. The intermediate-temperature fuel cell according to any one of claims 1-4, characterized in that: The first air supply path includes a first air filter (6), a first fan (7), a first flow meter (8), and an air preheater (9) connected in sequence by pipelines. The air preheater (9) is connected to the combustion zone of the reformer (1).

6. The intermediate-temperature fuel cell according to any one of claims 1-4, characterized in that: The methanol-water combustion supply path includes a methanol-water supply pump (10), a first methanol-water tank (11), a first filter (12), a combustion pump (13), a first check valve (14), and a vaporization heater (15) connected in sequence by pipelines. The vaporization heater (15) is connected to the combustion zone of the reformer (1).

7. The intermediate-temperature fuel cell according to any one of claims 1-4, characterized in that: The methanol-water reaction supply path includes a second methanol-water tank (16), a second filter (17), a reforming pump (18), and a second check valve (19) connected in sequence by pipelines. The second check valve (19) is connected to the reaction zone of the reformer (1).

8. The intermediate-temperature fuel cell according to any one of claims 1-4, characterized in that: The medium circulation water circuit includes an expansion tank (20), an air-cooled condenser (21), a circulation pump (22), and a circulation water heater (23). The expansion tank (20), the air-cooled condenser (21), the circulation pump (22), the circulation water heater (23), and the fuel cell stack (2) are connected in sequence to form a circulation water circuit.

9. The intermediate-temperature fuel cell according to any one of claims 1-4, characterized in that: The second air path includes a second air filter (24), a second fan (25), and a second flow meter (26) connected in sequence by pipes. The second flow meter (26) is connected to the fuel cell stack (2).

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