Compressed air supply system for hydrogen fuel cell stack test bench

Abstract

The utility model relates to a compressed air supply system for a hydrogen fuel cell stack test board, which comprises an air compressor, a buffer tank and a drying machine which are sequentially connected through a pipeline, and a primary filter is arranged on the pipeline between the buffer tank and the drying machine. A second-stage filter and a third-stage filter which are connected in series are arranged on a pipeline between the drying machine and the gas using end, a bypass pipeline is arranged between the first-stage filter and the second-stage filter, a pressure stabilizing protection valve is arranged on the bypass pipeline, and when the pressure in the bypass pipeline exceeds a set upper limit value, the pressure stabilizing protection valve is opened to release pressure, and when the pressure exceeds a set lower limit value, the pressure stabilizing protection valve is opened to release pressure. And the pressure stabilizing protection valve is closed. By means of the action of the pressure stabilizing protection valve, the gas release amount of the system is manually increased when small-flow gas is used, the air compressor is kept in a relatively stable operation state, the needed size of the buffer tank becomes smaller, a large-capacity buffer tank is not needed any more, the weight and space occupation of the skid-mounted station can be indirectly reduced, and the skid-mounted station is convenient to use. Possible potential safety hazards are avoided.

Description

Technical Field

[0001] This utility model relates to the field of compressed air supply technology, specifically a compressed air supply system for a hydrogen fuel cell stack test bench. Background Technology

[0002] The statements in this section are merely background information related to this utility model and do not necessarily constitute prior art.

[0003] During hydrogen fuel cell stack testing, various power conditions (10% to 100% of rated power) require load testing. This necessitates compressed air that can vary over a very wide flow range, for example, from 600 L / min to 6000 L / min, with the maximum flow rate demanding up to 10 times the minimum flow rate. However, currently, selecting air compressors based solely on the maximum air consumption results in compressors with excessively large capacities (most air compressors' maximum flow rate is only twice the minimum). When using the minimum air consumption, the compressor's start-up causes the pressure in the storage tank and pipelines to exceed the compressor's set pressure limit, leading to an immediate shutdown. When low-volume air consumption continues, the compressor restarts immediately when the pressure in the storage tank and pipelines falls below the compressor's set pressure limit. This frequent start-stop phenomenon causes inverter malfunctions and other problems, significantly reducing the lifespan of compressor components, increasing maintenance costs, and creating instability in the compressed air supply system.

[0004] To address the aforementioned issues, existing technologies typically involve installing a large-capacity buffer tank at the air compressor outlet to handle changes in air consumption. However, large-capacity buffer tanks occupy a significant area and space and can easily lead to safety problems. Utility Model Content

[0005] To address the technical problems mentioned above, this utility model provides a compressed air supply system for a hydrogen fuel cell stack test bench. The compressed air supply system is arranged in the form of a skid-mounted station, in which a relatively small buffer tank is arranged, and a pressure stabilizing protection valve is installed after the buffer tank. The pressure stabilizing protection valve opens or closes according to the change of the gas pressure, thereby increasing the leakage volume and quickly reducing the pressure of the buffer tank. This makes it less likely for the air compressor to reach the set pressure upper limit, thus maintaining a relatively more stable working state and reducing frequent start-stops.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This utility model provides a compressed air supply system for a hydrogen fuel cell stack test bench, including an air compressor, a buffer tank, and a dryer connected in sequence by pipes. A primary filter is installed on the pipe between the buffer tank and the dryer. A secondary filter and a tertiary filter are connected in series on the pipe between the dryer and the air-consuming end. A bypass pipe is provided between the primary filter and the secondary filter. A pressure stabilizing protection valve is installed on the bypass pipe. When the pressure in the bypass pipe exceeds a set upper limit value, the pressure stabilizing protection valve opens to release pressure. When the pressure exceeds a set lower limit value, the pressure stabilizing protection valve closes.

[0008] Furthermore, the air compressor has a heat dissipation channel and a compressor drain port.

[0009] Furthermore, the bottoms of the buffer tank, primary filter, secondary filter, and tertiary filter are all connected to a drain pipe, which is equipped with a drain outlet.

[0010] Furthermore, the bypass pipe is connected to the air inlet and outlet of the dryer. After the compressed air is discharged from the primary filter, it is divided into two branches. One branch enters the secondary filter through the bypass pipe, and the other branch enters the secondary filter after passing through the dryer.

[0011] Furthermore, the bypass pipeline is equipped with a pressure relief regulating valve and a bypass valve, and a pressure stabilizing protection valve is installed between the pressure relief regulating valve and the bypass valve. When the bypass valve is opened, the bypass pipeline is activated. The pressure relief regulating valve is used to regulate the amount of gas entering the bypass pipeline and cooperates with the pressure stabilizing protection valve to release the gas.

[0012] Furthermore, the dryer is a micro-heat adsorption dryer with two adsorption tanks, which achieve moisture adsorption through the alternating operation of the two adsorption tanks.

[0013] Furthermore, the outlet of the pressure stabilizing protection valve is connected to a pressure relief protection silencer.

[0014] Furthermore, the air compressor, buffer tank, and dryer are connected to a support structure inside the skid-mounted station.

[0015] Furthermore, the air intake window of the skid-mounted station is equipped with a dustproof net.

[0016] Furthermore, the skid-mounted station is equipped with a temperature control system and an automatic heating system, which uses temperature sensors and heaters to maintain the operating temperature of the air compressor between 0 and 45°C.

[0017] Compared with existing technologies, one or more of the above technical solutions have the following beneficial effects:

[0018] 1. A pressure-regulating protection valve is introduced into the compressed air supply system. During low-flow testing of the hydrogen fuel cell stack, if the pressure in the bypass pipeline continuously rises and exceeds the set upper limit, the pressure-regulating protection valve opens, releasing the gas in the bypass pipeline to the external environment. This artificially increases the release capacity of the buffer tank, preventing the air compressor from reaching its set pressure upper limit and keeping the air compressor in a continuous operating state, reducing the frequency of shutdowns. Conversely, when the compressed air consumption required for stack testing gradually increases, causing the compressed air pressure in the system to continuously drop and exceed the set lower limit, the pressure-regulating protection valve closes, ceasing pressure release. This maintains the air compressor in a relatively more stable operating state, reducing frequent start-stop cycles.

[0019] 2. By utilizing the action of the pressure stabilizing protection valve, the gas release of the system is artificially increased when the gas flow rate is low, so that the air compressor maintains a relatively more stable operating state, instead of the traditional run-stop-run cycle. This makes the required volume of the buffer tank smaller, eliminating the need for a large-capacity buffer tank. This can indirectly reduce the weight and space occupation of the skid-mounted station and avoid potential safety hazards (such as equipment height exceeding the limit and supervision issues caused by a large-capacity buffer tank). Attached Figure Description

[0020] The accompanying drawings, which form part of this specification, are used to provide a further understanding of this utility model. The illustrative embodiments of this utility model and their descriptions are used to explain this utility model and do not constitute an improper limitation of this utility model.

[0021] Figure 1 This is a schematic diagram of the compressed air supply system for the hydrogen fuel cell stack test bench provided by this utility model;

[0022] Figure 2 This is a schematic diagram of the skid-mounted station structure formed by the compressed air supply system for the hydrogen fuel cell stack test bench provided by this utility model.

[0023] Figure 1 The components are as follows: 1. Air supply end; 2. High-efficiency precision filter; 3. Dust filter; 4. Drainage pipe; 5. Micro-heat adsorption dryer; 6. Pressure relief protection silencer; 7. Pre-filter; 8. Pipe drain outlet; 9. Oil-free variable frequency screw air compressor; 10. Compressor drain outlet; 11. Air compressor heat dissipation channel; 12. Buffer tank; 13. Pressure relief regulating valve; 14. Pressure stabilizing protection valve; 15. Bypass pipe; 16. Air inlet window; 17. Bypass valve.

[0024] Figure 2 In the middle: 10 skid-mounted stations, 20 temperature control units. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] It should be noted that the following detailed description is exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0027] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this utility model. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0028] Hydrogen fuel cell testing typically includes testing of hydrogen fuel cell units, fuel cell stacks, power generation systems, and auxiliary components. In hydrogen fuel cell stack testing, the test bench needs to control parameters such as temperature, humidity, pressure, and flow rate of hydrogen and air to verify the electrical performance of the stack at different power levels. Therefore, current hydrogen fuel cell stack test benches themselves require compressed air supply conditions with specific pressure, flow rate, and cleanliness. The compressed air supplied to the hydrogen fuel cell stack test bench must be oil-free, water-free, and have a particle diameter of less than 0.01 μm.

[0029] The compressed air supply for laboratory hydrogen fuel cell stack test benches can be provided by either a gas supply system with an air compressor as the main component or by compressed air supply from storage containers such as tube bundle carts. For a single laboratory stack test bench application, the former has advantages due to its flexible layout, compact structure, and high gas supply timeliness, while the latter has certain disadvantages due to the need for a large site, high cost, and the need to establish operational procedures and corresponding safety isolation measures.

[0030] When using a gas supply system as the compressed air source, the air compressor's specifications must be selected based on the maximum air flow rate. However, during hydrogen fuel cell testing, the difference between the maximum and minimum air flow rates is nearly tenfold. When using the minimum air flow rate, the air compressor's start-up causes the pressure in the storage tank and pipelines to exceed the compressor's set upper pressure limit, resulting in an immediate compressor shutdown. When the air flow rate continues to be low, the compressor will immediately start again when the pressure in the storage tank and pipelines falls below the compressor's set lower pressure limit. This cycle repeats, leading to frequent start-stop cycles and potentially causing inverter malfunctions in the air compressor.

[0031] Therefore, the following embodiment provides a compressed air supply system for a hydrogen fuel cell stack test bench. The compressed air supply system is arranged in the form of a skid-mounted station, in which a relatively small buffer tank is arranged, and a pressure regulating protection valve is installed after the buffer tank. The pressure regulating protection valve opens or closes according to the change of the gas pressure, thereby increasing the leakage volume and quickly reducing the pressure of the buffer tank. This makes it less likely for the air compressor to reach the set pressure upper limit value, thus maintaining a relatively more stable working state and reducing frequent start-stop.

[0032] A compressed air supply system for a hydrogen fuel cell stack test bench includes an air compressor, a buffer tank, and a dryer connected in sequence by pipes. A primary filter is installed on the pipe between the buffer tank and the dryer. A secondary filter and a tertiary filter are installed in series on the pipe between the dryer and the air-consuming end. A bypass pipe is provided between the primary filter and the secondary filter. A pressure stabilizing protection valve is installed on the bypass pipe. The outlet of the pressure stabilizing protection valve is connected to a pressure relief protection silencer.

[0033] When the pressure in the bypass pipeline continues to rise and exceeds the set value, the pressure stabilizing protection valve opens to release the excess gas to the external environment, preventing the air compressor from reaching its set pressure limit and keeping the air compressor in operation.

[0034] When the pressure in the bypass pipeline continues to drop and exceeds the set value, the pressure stabilizing protection valve closes and stops releasing pressure.

[0035] Optionally, the air compressor has an air compressor heat dissipation channel 11 and a compressor drain port 10.

[0036] Optionally, the bottoms of the buffer tank 12, the primary filter, the secondary filter, and the tertiary filter are all connected to the drain pipe 4, and the drain pipe 4 discharges the water in the compressed air to the external environment through the drain outlet 8.

[0037] Optionally, a bypass pipe is connected to the air inlet and outlet of the dryer. After the compressed air is discharged from the primary filter, it is divided into two branches. One branch enters the secondary filter directly without passing through the dryer, and the other branch enters the secondary filter after passing through the dryer. The bypass pipe is equipped with a pressure relief regulating valve 13 and a bypass valve 17. A pressure stabilizing protection valve 14 is provided between the pressure relief regulating valve 13 and the bypass valve 17. When the bypass valve 17 is opened, the bypass pipe is activated. The pressure relief regulating valve 13 is used to regulate the amount of gas entering the bypass pipe and cooperates with the pressure stabilizing protection valve 14 to release the gas.

[0038] like Figure 1 As shown, the functional principles of each component in the compressed air supply system are as follows:

[0039] Gas supply end 1: Gas enters the hydrogen fuel cell stack test bench through this pipe.

[0040] High-efficiency precision filter 2: The dust content in the air is less than 0.01μm, and it is a third-stage filter to achieve dust-free gas.

[0041] Dust filter 3: Air dust content less than 1μm, second-stage filtration.

[0042] Drainage pipe 4: Moisture generated by the high-efficiency precision filter, dust filter, pre-filter, dryer, and buffer tank is discharged through this pipe.

[0043] The dryer is a micro-heat adsorption dryer 5: It dries the passing gas and has two devices, A and B tanks, which work independently. When the moisture content in tank A is too high during operation, the automatic switching device starts tank B to dry the gas. At the same time, the heater is turned on to heat the device in tank A to remove the moisture, so that it can be switched back to the dryer body later.

[0044] Pressure relief protection silencer 6: Eliminates the noise generated when the pressure relief valve is open, achieving a noise reduction effect.

[0045] Pre-filter 7: Air dust content less than 1μm, first stage filtration.

[0046] Drain outlet 8: Water in drainage pipe 4 is discharged through this outlet.

[0047] The air compressor is an oil-free variable frequency screw air compressor 9: It pressurizes the incoming air, selects the oil-free type, and saves energy through frequency conversion.

[0048] Drain outlet 10: Air compressor outlet.

[0049] Air compressor heat dissipation channel 11: The heat generated by the air compressor is discharged through this channel, reducing the temperature of the air compressor.

[0050] Buffer tank 12: Stores the gas produced by the air compressor and provides a buffering effect.

[0051] Pressure relief regulating valve 13: Maintains a certain opening degree to coordinate with the air compressor to regulate the flow rate of the pressure relief pipeline.

[0052] Pressure stabilizing protection valve 14: When the air pressure in the pipeline is greater than the set value, the pressure stabilizing protection valve opens and performs pressure stabilization protection by releasing air.

[0053] Bypass pipe 15: Open during maintenance.

[0054] Air inlet 16: The air inlet of the skid-mounted station 10, equipped with a dustproof screen.

[0055] Bypass valve 17 is opened, and gas enters the bypass pipeline.

[0056] The gas generated by the air compressor enters a buffer tank for buffering. After passing through three stages of filtration (2, 3, 7) and drying (5), the gas enters the hydrogen fuel cell stack test bench. Without the pressure regulating protection valve 14, when the gas flow demand of the stack test bench is small, the air compressor will immediately stop when it starts, as the pressure in the storage tank and pipeline exceeds the upper limit of the air compressor's set pressure. When the gas supply continues to be small, the air compressor will start immediately when the pressure in the storage tank and pipeline is lower than the lower limit of the air compressor's set pressure. Under a specific gas supply system, this cycle repeats, resulting in frequent start-stop phenomena, which seriously affects the lifespan of the air compressor, the stability of the gas supply system, and the testing of the fuel cell stack.

[0057] After adding the pressure stabilizing protection valve 14, the pressure stabilizing valve can detect the pressure in the pipeline. When the pressure increases beyond a certain limit, the pressure stabilizing protection valve opens to release pressure and exhaust gas through the venting pipeline, thereby ensuring that the gas pressure in the pipeline is within a stable range. If the pressure does not reach the upper limit set by the air compressor, the air compressor will not stop, thus ensuring the stable operation of the air compressor. In addition, a silencer (6) is installed next to the pressure stabilizing valve to reduce noise generation. When the gas demand of the fuel cell stack test bench gradually increases, the pressure value in the pipeline will continue to decrease due to the increase in gas consumption. When the pressure is lower than a certain limit set by the pressure stabilizing protection valve, the pressure stabilizing protection valve will close, and the venting pipeline will no longer release pressure, thereby ensuring the supply of compressed air at the gas consumption end of the test bench to meet the test requirements.

[0058] Air compressors have specific operating temperature requirements, typically ranging from 0 to 45°C. Therefore, a temperature control system and an automatic heating system are added to the skid-mounted station 10. These systems constantly monitor the ambient temperature around the air compressor. When the ambient temperature falls below the set lower limit, the heating module is activated to ensure the temperature inside the skid-mounted station exceeds the lower operating temperature limit of the air compressor, thus guaranteeing its normal operation. Simultaneously, a heat dissipation exhaust duct is installed above the air compressor in the skid-mounted station, ensuring direct heat dissipation to the outside of the station, thereby guaranteeing its normal operation. The layout of the skid-mounted station 10 is shown below. Figure 2 As shown, the temperature control unit 20 is used to control the ambient temperature around the air compressor.

[0059] This solution addresses the issue of frequent start-stop cycles of air compressors in low-flow-rate areas, enabling the system to meet the full range of compressed air flow requirements during hydrogen fuel cell stack testing. The supply system is characterized by high flexibility, high integration, low cost, and low noise. The skid-mounted station is equipped with a temperature control system and automatic heating equipment to ensure normal operation of the air compressor in low-temperature environments. It can be moved as a whole using a crane or forklift. The skid-mounted station is insulated, ventilated, and rainproof. It can still operate normally in ambient temperatures ranging from -20°C to 46°C. The air inlet windows of the skid-mounted station are equipped with dust filters that are easy to clean and replace. A conveniently opening door on the side of the skid-mounted station facilitates maintenance. The air compressor inside the skid-mounted station requires heat dissipation and exhaust ducts, condensate drainage pipes, and insulation measures to prevent high-temperature shutdowns in summer and pipe freezing in low-temperature environments in winter.

[0060] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A compressed air supply system for a hydrogen fuel cell stack test bench, characterized in that, It includes an air compressor, a buffer tank, and a dryer connected in sequence by pipes. A primary filter is installed on the pipe between the buffer tank and the dryer. A secondary and tertiary filter are installed in series on the pipe between the dryer and the air-consuming end. A bypass pipe is installed between the primary and secondary filters. A pressure stabilizing protection valve is installed on the bypass pipe. When the pressure in the bypass pipe exceeds the set upper limit value, the pressure stabilizing protection valve opens to release pressure. When it exceeds the set lower limit value, the pressure stabilizing protection valve closes.

2. The compressed air supply system for a hydrogen fuel cell stack test bench as described in claim 1, characterized in that, The air compressor has a heat dissipation channel and a drain outlet.

3. The compressed air supply system for a hydrogen fuel cell stack test bench as described in claim 1, characterized in that, The bottoms of the buffer tank, primary filter, secondary filter, and tertiary filter are all connected to a drainage pipe, which is equipped with a drain outlet.

4. The compressed air supply system for a hydrogen fuel cell stack test bench as described in claim 1, characterized in that, The bypass pipe is connected to the air inlet and outlet of the dryer. After the compressed air is discharged from the primary filter, it is divided into two branches. One branch enters the secondary filter through the bypass pipe, and the other branch enters the secondary filter after passing through the dryer.

5. The compressed air supply system for a hydrogen fuel cell stack test bench as described in claim 1, characterized in that, The bypass pipeline is equipped with a pressure relief regulating valve and a bypass valve. A pressure stabilizing protection valve is provided between the pressure relief regulating valve and the bypass valve. When the bypass valve is opened, the bypass pipeline is activated. The pressure relief regulating valve is used to regulate the amount of gas entering the bypass pipeline and cooperates with the pressure stabilizing protection valve to release gas.

6. The compressed air supply system for a hydrogen fuel cell stack test bench as described in claim 1, characterized in that, The dryer is a micro-heat adsorption dryer with two adsorption tanks, which achieve moisture adsorption through the alternating operation of the two adsorption tanks.

7. The compressed air supply system for a hydrogen fuel cell stack test bench as described in claim 1, characterized in that, The outlet of the pressure stabilizing protection valve is connected to a pressure relief protection silencer.

8. The compressed air supply system for a hydrogen fuel cell stack test bench as described in claim 1, characterized in that, The air compressor, buffer tank, and dryer are connected to a support frame inside the skid-mounted station.

9. The compressed air supply system for a hydrogen fuel cell stack test bench as described in claim 8, characterized in that, The skid-mounted station has a dustproof net on its air intake window.

10. The compressed air supply system for a hydrogen fuel cell stack test bench as described in claim 8, characterized in that, The skid-mounted station is equipped with a temperature control system and an automatic heating system, which uses temperature sensors and heaters to maintain the operating temperature of the air compressor between 0 and 45°C.

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