Air supply system for hydrogen fuel cells capable of improving hydrogen utilization

Abstract

The utility model discloses an air supply system for a hydrogen fuel cell capable of improving the utilization rate of hydrogen, comprising a pressure swing adsorption tank with a molecular sieve for adsorbing nitrogen, the upper and lower ends of the pressure swing adsorption tank are respectively connected with a tank body input pipe with a tank input control valve and a tank body output pipe with a tank output control valve, an adsorption tank oxygen content sensor is arranged on the tank body output pipe, the tank body input pipe is connected with an air input pipe, the tank body output pipe is connected with a buffer storage tank, the buffer storage tank is connected with a buffer storage tank output pipe, the air input pipe is connected with the buffer storage tank output pipe through a bypass pipe, a bypass flow regulating valve is arranged on the bypass pipe, and a buffer output oxygen content sensor is arranged on the buffer storage tank output pipe. The utility model has the advantages of being able to provide air with a high oxygen concentration for the hydrogen fuel cell, thereby improving the utilization rate of hydrogen during the operation of the hydrogen fuel cell, and effectively extending the service life of the proton exchange membrane in the hydrogen fuel cell.

Description

Technical Field

[0001] The utility model relates to the technical field of hydrogen fuel cells, in particular to an air supply system for a hydrogen fuel cell. Background Art

[0002] A hydrogen fuel cell is a power generation device that converts the chemical energy of hydrogen and oxygen into electrical energy. A hydrogen fuel cell mainly includes a proton exchange membrane, an electrochemical reaction catalyst, and a bipolar plate. During the operation of a hydrogen fuel cell, hydrogen is fed to the anode, and under the action of the electrochemical reaction catalyst, hydrogen molecules are ionized into positively charged hydrogen ions and release negatively charged electrons. The hydrogen ions pass through the proton exchange membrane to the cathode, and under the action of the catalyst, the oxygen at the cathode reacts with the hydrogen ions and electrons to generate water. At present, air is used as the oxygen supply source in hydrogen fuel cells.

[0003] The following technical problems have been found in the operation of current hydrogen fuel cells: the molar ratio required for the reaction of hydrogen and oxygen is 2:1, while the oxygen content in the air is usually around 21%. Directly using air as an oxygen supply source causes the hydrogen in the hydrogen fuel cell to always be in an excess state, resulting in low hydrogen utilization and, in turn, low efficiency of the hydrogen fuel cell.

[0004] In order to solve the above technical problems, the technical means currently used are usually to increase the air volume on the oxygen side by pressurizing the air to improve the utilization efficiency of hydrogen. However, increasing the air pressure on the oxygen side will lead to pressure imbalance on both sides of the proton exchange membrane and greatly shorten the service life of the proton exchange membrane. At the same time, a high-power air compressor is required, which will greatly increase the operating cost of hydrogen fuel cells. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide an air supply system for a hydrogen fuel cell which can improve the utilization rate of hydrogen. The air supply system has a simple structure and low cost, and can effectively improve the utilization rate of hydrogen, thereby greatly improving the working efficiency of the hydrogen fuel cell.

[0006] In order to solve the above problems, the technical solution adopted by the utility model is: an air supply system for a hydrogen fuel cell capable of improving the utilization rate of hydrogen, comprising a pressure swing adsorption tank with a molecular sieve for adsorbing nitrogen, the upper and lower ends of the pressure swing adsorption tank are respectively connected with a tank input pipe with a tank input control valve and a tank output pipe with a tank output control valve, an adsorption tank oxygen content sensor for detecting the oxygen content is arranged on the tank output pipe, the tank input pipe is connected to the air input pipe, the tank output pipe is connected to a buffer storage tank, a buffer storage tank is connected to a buffer storage tank output pipe, the air input pipe is connected to the buffer storage tank output pipe through a bypass pipe, a bypass flow regulating valve is arranged on the bypass pipe, and a buffer output oxygen content sensor for monitoring the oxygen content is arranged on the buffer storage tank output pipe.

[0007] Furthermore, in the aforementioned air supply system for a hydrogen fuel cell capable of improving hydrogen utilization, an air compressor is provided on the air input pipe.

[0008] Furthermore, in the aforementioned air supply system for a hydrogen fuel cell capable of improving hydrogen utilization, an air filter for removing particulate impurities in the air is provided at the input end of the air input pipe.

[0009] Furthermore, in the aforementioned air supply system of the hydrogen fuel cell capable of improving hydrogen utilization, two pressure swing adsorption tanks are arranged between the air input pipe and the buffer storage tank, and the upper and lower ends of each pressure swing adsorption tank are respectively connected to a tank input pipe with a tank input control valve and a tank output pipe with a tank output control valve, and each tank output pipe is provided with an adsorption tank output oxygen content sensor for detecting the oxygen content; the air input pipe is connected to the two tank input pipes, and the two tank output pipes are connected to the buffer storage tank through the buffer tank input pipe.

[0010] Furthermore, in the aforementioned air supply system of the hydrogen fuel cell capable of improving hydrogen utilization, each tank body input pipe is provided with an adsorption tank emptying pipe with an emptying control valve, and both adsorption tank emptying pipes are connected to an emptying main pipe.

[0011] Furthermore, in the aforementioned air supply system for a hydrogen fuel cell capable of improving hydrogen utilization, a purge pipeline with a purge control valve is connected between the two tank output pipes.

[0012] Furthermore, in the aforementioned air supply system for a hydrogen fuel cell capable of improving hydrogen utilization, a humidifier is also provided on the output pipe of the buffer storage tank.

[0013] The advantages of the utility model are: 1. It can provide air with a high oxygen concentration for hydrogen fuel cells, and can increase the oxygen content in the air to a molar concentration of about 50%. This can control the stoichiometric ratio of the gas on both sides of the proton exchange membrane to about 1:1 under the premise that the air pressure on both sides of the proton exchange membrane is relatively balanced, thereby greatly improving the utilization rate of hydrogen during the operation of the hydrogen fuel cell, thereby greatly improving the working efficiency of the hydrogen fuel cell, and can effectively extend the service life of the proton exchange membrane in the hydrogen fuel cell. 2. The structure is simple and the equipment cost is low. After the oxygen concentration increases, there is no need to use a high-power air compressor, which can greatly reduce the cost of using hydrogen fuel cells. 3. It can continuously provide air with a high oxygen concentration for hydrogen fuel cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The utility model is a schematic diagram of the working principle of the air supply system of the hydrogen fuel cell capable of improving the hydrogen utilization rate. DETAILED DESCRIPTION

[0015] The present invention will be further described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0016] like Figure 1 As shown, an air supply system for a hydrogen fuel cell that can improve hydrogen utilization efficiency is described by taking two pressure swing adsorption tanks with molecular sieves for adsorbing nitrogen as an example. The two pressure swing adsorption tanks are respectively a first pressure swing adsorption tank 1 and a second pressure swing adsorption tank 2. The advantage of setting two pressure swing adsorption tanks is that they can work alternately with each other, thereby achieving uninterrupted gas supply. The upper and lower ends of the first pressure swing adsorption tank 1 are respectively connected to a first tank body input pipe 11 with a first tank input control valve 111 and a first tank body output pipe 12 with a first tank output control valve 121, and a first adsorption tank oxygen content sensor 122 for detecting oxygen content is provided on the first tank body output pipe 12. The upper and lower ends of the second pressure swing adsorption tank 2 are respectively connected to a second tank body input pipe 21 with a second tank input control valve 211 and a second tank body output pipe 22 with a second tank output control valve 221, and a second adsorption tank oxygen content sensor 222 for detecting oxygen content is provided on the second tank body output pipe 22.

[0017] In this embodiment, the first tank input pipe 11 and the second tank input pipe 21 are connected to the air input pipe 3, and the first tank output pipe 12 and the second tank output pipe 22 are connected to the buffer tank 4 through the buffer tank input pipe 41. The buffer tank 4 is connected to the buffer tank output pipe 42, and the air input pipe 3 is connected to the buffer tank output pipe 42 through the bypass pipe 5. The bypass pipe 5 is provided with a bypass flow regulating valve 51, and the buffer tank output pipe 42 is provided with a buffer output oxygen content sensor 421 for monitoring oxygen content. In this embodiment, the buffer tank output pipe 42 is also provided with a humidifier 422.

[0018] In this embodiment, a first adsorption tank emptying pipe 13 with a first emptying control valve 131 is provided on the first tank body input pipe 11, and a second adsorption tank emptying pipe 23 with a second emptying control valve 231 is provided on the second tank body input pipe 21. Both adsorption tank emptying pipes are connected to the main emptying pipe 6.

[0019] In addition, a purge pipeline 7 with a purge control valve 71 is connected between the two tank output pipes.

[0020] In this embodiment, in order to provide power for air operation, an air compressor 31 is provided on the air input pipe 3. In addition, in order to ensure the cleanliness of the air provided to the hydrogen fuel cell and reduce the failure rate of the hydrogen fuel cell, an air filter 32 for removing particulate impurities in the air is provided at the input end of the air input pipe 3.

[0021] The working principle is as follows: taking the first pressure swing adsorption tank 1 working and the second pressure swing adsorption tank 2 suspended as an example, the first tank input control valve 111 and the first tank output control valve 121 are opened, and the first emptying control valve 131, the second emptying control valve 231, the second tank input control valve 211, the second tank output control valve 221, the purge control valve 71, and the bypass flow regulating valve 51 are closed.

[0022] The air is filtered and purified by the air filter 32, and then enters the first pressure swing adsorption tank 1 through the first tank body input pipe 11 by the air compressor 31. The nitrogen in the air is adsorbed by the molecular sieve in large quantities in the first pressure swing adsorption tank 1, so the nitrogen content in the air decreases and the oxygen content increases relatively. Preferably, the nitrogen content in the air is reduced until the molar ratio of nitrogen to oxygen in the air is 1:1, that is, the oxygen content is increased to about 50%. Of course, the specific reduction of the nitrogen content can also be set according to the actual needs of the hydrogen fuel cell. The adsorption amount of nitrogen can usually be controlled by controlling the time the air stays in the pressure swing adsorption tank. The air with reduced nitrogen content enters the buffer storage tank 4 through the first tank body output pipe 12 and the buffer storage tank input pipe 41. The first adsorption tank oxygen content sensor 122 detects the oxygen content of the output air with reduced nitrogen content to ensure that the nitrogen content in the output air meets the requirements. The air with reduced nitrogen content in the buffer storage tank 4 is output to the outside through the buffer storage tank output pipe 42. The buffer output oxygen content sensor 421 monitors the oxygen content in the output air in real time. If the buffer output oxygen content sensor 421 detects that the oxygen content in the air is higher than the preset value, the bypass flow regulating valve 51 is controlled to open, so that the air that has not been adsorbed by the molecular sieve directly enters the buffer storage tank output pipe 42 through the bypass pipe 5 to reduce the oxygen content in the air. The opening of the bypass flow regulating valve 51 can be adjusted, and the appropriate opening can ensure that the oxygen content in the air output from the buffer storage tank output pipe 42 meets the requirements. The humidifier 422 is used to humidify the output nitrogen-reduced air.

[0023] After the first pressure swing adsorption tank 1 has been working for a long time, the molecular sieve inside it is fully loaded, and the second pressure swing adsorption tank 2 starts adsorption work, and the first pressure swing adsorption tank 1 suspends adsorption work and regenerates. At this time, the first tank input control valve 111, the first tank output control valve 121, the bypass flow regulating valve 51, and the second emptying control valve 231 are in a closed state; the second tank input control valve 211, the second tank output control valve 221, the purge control valve 71, and the first emptying control valve 131 are open.

[0024] The air is filtered and purified by the air filter 32, and then enters the second pressure swing adsorption tank 2 through the second tank body input pipe 21 by the air compressor 31. The nitrogen in the air is adsorbed by the molecular sieve in the second pressure swing adsorption tank 2, so the nitrogen content in the air decreases and the oxygen content increases relatively. Similarly, the nitrogen content in the air is reduced to a state where the molar ratio of nitrogen to oxygen in the air is 1:1, that is, the oxygen content is increased to about 50%. The second adsorption tank oxygen content sensor 222 detects the oxygen content of the output air with reduced nitrogen content. The air with reduced nitrogen content passes through the second tank body output pipe 22, and a part of it enters the first pressure swing adsorption tank 1 through the purge pipeline 7 and the first tank body output pipe 12, thereby back-blowing the molecular sieve therein, so that the nitrogen is separated from the molecular sieve and discharged outward through the first tank body input pipe 11, the first adsorption tank emptying pipe 13, and the emptying main pipe 6 until the molecular sieve in the first pressure swing adsorption tank 1 is regenerated. At this time, the purge control valve 71 is closed and the first emptying control valve 131 is closed.

[0025] Another part of the air with reduced nitrogen content enters the buffer tank 4 through the buffer tank input pipe 41, and the air with reduced nitrogen content in the buffer tank 4 is output through the buffer tank output pipe 42. The buffer output oxygen content sensor 421 monitors the oxygen content in the output air in real time. If the buffer output oxygen content sensor 421 detects that the oxygen content in the air is higher than the preset value, the bypass flow regulating valve 51 is controlled to open, so that the air that has not been treated with molecular adsorption can directly enter the buffer tank output pipe 42 through the bypass pipe 5 to reduce the oxygen content in the air. The opening of the bypass flow regulating valve 51 can be adjusted, and the appropriate opening can ensure that the oxygen content in the air output from the buffer tank output pipe 42 meets the requirements. The humidifier 422 is used to humidify the output nitrogen-reduced air.

[0026] The advantages of the utility model are: 1. It can provide air with a high oxygen concentration for hydrogen fuel cells, and can increase the oxygen content in the air to a molar concentration of about 50%. This can control the stoichiometric ratio of the gas on both sides of the proton exchange membrane to about 1:1 under the premise that the air pressure on both sides of the proton exchange membrane is relatively balanced, thereby greatly improving the utilization rate of hydrogen during the operation of the hydrogen fuel cell, thereby greatly improving the working efficiency of the hydrogen fuel cell, and can effectively extend the service life of the proton exchange membrane in the hydrogen fuel cell. 2. The structure is simple and the equipment cost is low. After the oxygen concentration increases, there is no need to use a high-power air compressor, which can greatly reduce the cost of using hydrogen fuel cells. 3. It can continuously provide air with a high oxygen concentration for hydrogen fuel cells.

Claims

1. An air supply system for a hydrogen fuel cell capable of improving hydrogen utilization, characterized in that: It comprises a pressure swing adsorption tank with a molecular sieve for adsorbing nitrogen, the upper and lower ends of the pressure swing adsorption tank are respectively connected with a tank input pipe with a tank input control valve and a tank output pipe with a tank output control valve, the tank output pipe is provided with an adsorption tank oxygen content sensor for detecting the oxygen content, the tank input pipe is connected with an air input pipe, the tank output pipe is connected to a buffer storage tank, the buffer storage tank is connected with a buffer storage tank output pipe, the air input pipe is connected with the buffer storage tank output pipe through a bypass pipe, the bypass pipe is provided with a bypass flow regulating valve, and the buffer storage tank output pipe is provided with a buffer output oxygen content sensor for monitoring the oxygen content.

2. The air supply system for a hydrogen fuel cell capable of improving hydrogen utilization rate according to claim 1, characterized in that: An air compressor is arranged on the air input pipe.

3. The air supply system for a hydrogen fuel cell capable of improving hydrogen utilization rate according to claim 1, characterized in that: An air filter for removing particulate impurities in the air is arranged at the input end of the air input pipe.

4. The air supply system for a hydrogen fuel cell capable of improving hydrogen utilization rate according to claim 1, characterized in that: Two pressure swing adsorption tanks are arranged between the air input pipe and the buffer storage tank. The upper and lower ends of each pressure swing adsorption tank are respectively connected with a tank input pipe with a tank input control valve and a tank output pipe with a tank output control valve. Each tank output pipe is provided with an adsorption tank output oxygen content sensor for detecting the oxygen content. The air input pipe is connected to the two tank input pipes, and the two tank output pipes are connected to the buffer storage tank through the buffer storage tank input pipe.

5. The air supply system for a hydrogen fuel cell capable of improving hydrogen utilization rate according to claim 4, characterized in that: Each tank input pipe is provided with an adsorption tank drain pipe with a drain control valve, and both adsorption tank drain pipes are connected to the drain main pipe.

6. The air supply system for a hydrogen fuel cell capable of improving hydrogen utilization rate according to claim 4, characterized in that: A purge pipeline with a purge control valve is connected between the two tank output pipes.

7. The air supply system for a hydrogen fuel cell capable of improving hydrogen utilization rate according to claim 1, characterized in that: A humidifier is also provided on the output pipe of the buffer storage tank.

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