A liquid hydrogen pump test system based on hydrogen liquefier

Abstract

The present invention proposes a liquid hydrogen pump testing system based on a hydrogen liquefier, which specifically relates to the field of low-temperature detection technology. The liquid hydrogen pump testing system based on the hydrogen liquefier includes a testing unit, a discharging unit and a liquefaction unit. Different pipelines are used to simultaneously test the submersible pump and the high-pressure pump, and finally the gas is discharged into the low-pressure discharge pipe and the high-pressure discharge pipe. This system has higher safety and can better discharge hydrogen. Testing the submersible pump and the high-pressure pump using a cycle can also save hydrogen energy and avoid waste.

Description

Technical Field

[0001] The present invention relates to the field of low-temperature detection technology, and in particular to a liquid hydrogen pump testing system based on a hydrogen liquefier. Background Art

[0002] With the development of technology, hydrogen fuel cell vehicles and hydrogen fuel aircraft have been rapidly promoted. Liquid hydrogen has a higher storage density than gaseous hydrogen. In the field of heavy-duty commercial vehicles, the use of liquid hydrogen systems in vehicles can achieve a mass hydrogen storage density of more than 6.5%. Liquid hydrogen aircraft use large-volume hydrogen fuel tanks wrapped with carbon fiber and superconducting hydrogen-electric propulsion systems, with a mass hydrogen storage density of up to 70%. Therefore, liquid hydrogen storage and transportation hydrogen refueling stations will occupy a very important position in the hydrogen energy industry chain in the future.

[0003] Liquid hydrogen pumps, a key component in liquid hydrogen transportation applications, are primarily divided into high-pressure and centrifugal pumps. Due to their extreme operating environments, these pumps remain technically challenging. The design process requires thorough testing under realistic operating conditions. Currently, most domestic high-pressure hydrogen pump test platforms utilize open-loop systems. These pumps are tested by discharging ambient-temperature gas after vaporization from a high-pressure vaporizer to assess pump performance. This method struggles to eliminate the impact of tank heat leakage on pump characteristics, and exposure to air also creates heat transfer and leakage risks. While foreign high-pressure hydrogen pump test platforms lack high-pressure liquid hydrogen vaporizers, they place relatively high demands on the performance of test vessels, such as high-pressure, cryogenic hydrogen storage vessels, and pumps. The testing consumes significant amounts of liquid hydrogen, and direct high-altitude discharge of hydrogen after the test creates explosion and pollution risks. Furthermore, performance testing on centrifugal pump test benches is limited. The lack of accurate measurement of the pump tank liquid level and overall system flow rate prevents sufficient test data from being generated to comprehensively evaluate the performance of liquid hydrogen submersible pumps.

[0004] Application No. CN11465431A discloses a low-temperature performance test system and test method for a liquid hydrogen booster pump, which belongs to the field of liquid hydrogen booster pump testing technology. The low-temperature performance test system for a liquid hydrogen booster pump includes: a low-temperature storage and supply system, an exhaust method test system, an emergency exhaust system and a centralized high-exhaust system. The exhaust method test system has an inlet for communicating with a vaporizer, a first exhaust valve is provided at the inlet, and the vaporizer is connected to the outlet of the liquid hydrogen booster pump to be tested; the exhaust method test system includes: a throttling element, a first pressure gauge is provided at the inlet of the throttling element, and the first pressure gauge is used to detect the inlet and outlet pressure difference of the throttling element; the low-temperature performance test system for a liquid hydrogen booster pump of the present invention can test the flow rate of the liquid hydrogen booster pump to be tested through the exhaust method test system. When performing low-temperature performance testing on a principle prototype in the product development stage, the test can be completed more quickly and safely. However, the exhaust at the test end of the patent is only connected to an exhaust pipe. During discharge, high-pressure and low-pressure hydrogen cannot be discharged in a targeted manner, and the safety is low.

[0005] In view of this, the present invention proposes a liquid hydrogen pump testing system with higher safety and capable of detecting high and low pressure hydrogen emissions. Summary of the Invention

[0006] In order to solve the problem of being unable to discharge high and low pressure hydrogen, the present invention proposes a liquid hydrogen pump testing system based on a hydrogen liquefier.

[0007] The present invention is achieved through the following technical solutions:

[0008] The present invention proposes a liquid hydrogen pump testing system based on a hydrogen liquefier, comprising a testing unit, a discharging unit and a liquefaction unit, wherein:

[0009] The test unit includes a cold box, a liquid hydrogen storage tank arranged inside the cold box, a self-pressurizing vaporizer arranged outside the cold box, a first liquid hydrogen pool and a second liquid hydrogen pool, wherein both ends of the self-pressurizing vaporizer are respectively connected to the outlet end at the bottom and the inlet end at the top of the liquid hydrogen storage tank, a submersible pump is installed in the first liquid hydrogen pool, and a high-pressure pump is installed in the second liquid hydrogen pool;

[0010] The liquefaction unit includes a liquefier and a compressor, and the outlet end at the top of the liquid hydrogen storage tank is connected to the compressor and the liquefier in sequence, and then connected back to the inlet end at the top of the liquid hydrogen storage tank;

[0011] The dissipation unit includes a low-pressure vaporizer and a high-pressure vaporizer, wherein the outlet end of the low-pressure vaporizer is connected to a flame arrester and a low-pressure discharge pipe in sequence, and the outlet end of the high-pressure vaporizer is connected to another flame arrester and a high-pressure discharge pipe in sequence;

[0012] Two branches at one outlet end of the top of the liquid hydrogen storage tank are connected to the top gas return ports of the first liquid hydrogen pool and the second liquid hydrogen pool respectively;

[0013] The three branches at one bottom outlet end of the liquid hydrogen storage tank are respectively connected to the liquid inlet of the submersible pump in the first liquid hydrogen pool, the inlet end of the low-pressure vaporizer and the liquid inlet of the high-pressure pump in the second liquid hydrogen pool. The liquid outlet of the submersible pump in the first liquid hydrogen pool is connected to the first liquid hydrogen pool. One branch at the outlet end of the first liquid hydrogen pool is connected to another bottom outlet end of the bottom of the liquid hydrogen storage tank. Another branch at the outlet end of the first liquid hydrogen pool is connected to the inlet end of the low-pressure vaporizer and the outlet end of the high-pressure pump in the second liquid hydrogen pool is connected to the second liquid hydrogen pool. The outlet end of the second liquid hydrogen pool is respectively connected to the inlet end of the high-pressure vaporizer and the high-pressure exhaust pipe.

[0014] Furthermore, it also includes a first regulating valve and a second regulating valve, the first regulating valve is arranged between the liquid hydrogen storage tank and the outlet end of the liquefier, and the second regulating valve is arranged between the inlet end of the compressor and the top inlet of the liquid hydrogen storage tank.

[0015] Furthermore, it also includes a third regulating valve and a fourth regulating valve, the third regulating valve is arranged on the pipeline from the liquid hydrogen storage tank to the outside, and the fourth regulating valve is arranged between the liquid hydrogen storage tank and the inlet end of the self-pressurizing vaporizer.

[0016] Furthermore, it also includes a fifth regulating valve and a sixth regulating valve, the fifth regulating valve is arranged between the first liquid hydrogen pool return port and the top of the liquid hydrogen storage tank, and the sixth regulating valve is arranged between the second liquid hydrogen pool return port and the top of the liquid hydrogen storage tank.

[0017] Furthermore, it also includes a first valve group, a second valve group and a seventh regulating valve, wherein two ends of the first valve group are respectively connected to the liquid outlet of the first liquid hydrogen pool and the inlet of the low-pressure vaporizer, two ends of the second valve group are respectively connected to the return gas port of the second liquid hydrogen pool and the inlet of the low-pressure vaporizer, and two ends of the seventh regulating valve are respectively connected to the return gas port of the first liquid hydrogen pool and the inlet of the low-pressure vaporizer.

[0018] Furthermore, it also includes an eighth regulating valve, a ninth regulating valve, a first one-way valve and a liquid hydrogen flowmeter. The first branch at the bottom outlet end of the liquid hydrogen storage tank is connected in sequence to the eighth regulating valve and the liquid inlet of the submersible pump, and is connected in sequence from the outlet end of the submersible pump to the first liquid hydrogen pool, the liquid hydrogen flowmeter, the ninth regulating valve, the first one-way valve and the other bottom outlet end of the liquid hydrogen storage tank.

[0019] Furthermore, it also includes a tenth regulating valve and a second one-way valve, and the second branch at the bottom outlet end of the liquid hydrogen storage tank is connected to the tenth regulating valve, the low-pressure vaporizer, the flame arrester, the second one-way valve and the low-pressure exhaust pipe in sequence.

[0020] Furthermore, it also includes an eleventh regulating valve, a liquid hydrogen filter, a twelfth regulating valve and a third one-way valve. The third branch at the bottom outlet end of the liquid hydrogen storage tank is connected in sequence to the eleventh regulating valve, the liquid hydrogen filter and the liquid inlet of the high-pressure pump in the second liquid hydrogen pool, and is connected in sequence from the outlet end of the second liquid hydrogen pool to the twelfth regulating valve, the third one-way valve and the high-pressure vaporizer.

[0021] The improvement further includes a gas flow meter, a thirteenth regulating valve, a fourteenth regulating valve, a pressure reducing valve, and a fourth one-way valve. The outlet end of the high-pressure vaporizer is connected to the gas flow meter, the thirteenth regulating valve, the fourteenth regulating valve, the pressure reducing valve, the flame retardant, the fourth one-way valve and the high-pressure discharge pipe in sequence.

[0022] Furthermore, it also includes a third valve group, a fourth valve group and a fifth valve group, wherein two ends of the third valve group are respectively connected to the pipeline between the second liquid hydrogen pool and the high-pressure discharge pipe and the inlet end of the second regulating valve, two ends of the fourth valve group are respectively connected to the pipeline between the second liquid hydrogen pool and the high-pressure discharge pipe and the outlet end of the high-pressure vaporizer, and two ends of the fifth valve group are respectively connected to the pipeline between the second liquid hydrogen pool and the high-pressure discharge pipe and the inlet end of the fourteenth regulating valve.

[0023] Beneficial effects of the present invention:

[0024] (1) The liquid hydrogen pump testing system based on the hydrogen liquefier proposed in the present invention uses different pipelines to test the submersible pump and the high-pressure pump, and finally discharges the hydrogen into the low-pressure discharge pipe and the high-pressure discharge pipe. It is safer and can discharge hydrogen better. The use of circulation to test the submersible pump and the high-pressure pump can also save hydrogen energy and avoid waste.

[0025] (2) The liquid hydrogen pump test system based on the hydrogen liquefier proposed in the present invention divides the entire system into multiple modules, and each module performs the functions of liquefaction, supply, testing, and discharge respectively, which is convenient for disassembly, assembly, repair and maintenance.

[0026] (3) The liquid hydrogen pump test system based on the hydrogen liquefier proposed in the present invention can use the liquid hydrogen source + liquid hydrogen dewar to store liquid hydrogen + control valve group + high vacuum insulation pipeline + high-precision flow measurement and decompression and reheating discharge scheme to test the submersible pump and the high-pressure pump at the same time, and meet the performance and critical cavitation margin test requirements of the pump in a low temperature environment of not less than 20K, especially in a 20K liquid hydrogen and 77K liquid nitrogen environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is an overall structural diagram of the liquid hydrogen pump testing system based on the hydrogen liquefier of the present invention;

[0028] In the figure: liquefaction unit 1, liquefier 11, compressor 12, first regulating valve 13, second regulating valve 14, test unit 2, cold box 21, liquid hydrogen storage tank 22, self-pressurizing vaporizer 23, first liquid hydrogen pool 24, second liquid hydrogen pool 25, liquid hydrogen filter 26, third regulating valve 27, tenth regulating valve 28, fifth regulating valve 29, sixth regulating valve 210, eighth regulating valve 211, eleventh regulating valve 212, tenth regulating valve 213, ninth regulating valve 214, first one-way valve 215, seventh Regulating valve 216, second valve group 217, first valve group 218, liquid hydrogen flowmeter 219, discharging unit 3, low-pressure vaporizer 31, high-pressure vaporizer 32, flame retardant 33, low-pressure discharge pipe 34, high-pressure discharge pipe 35, gas flowmeter 36, twelfth regulating valve 37, third one-way valve 38, thirteenth regulating valve 39, fourteenth regulating valve 310, pressure reducing valve 311, second one-way valve 312, fourth one-way valve 313, third valve group 314, fourth valve group 315, fifth valve group 316;

[0029] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0030] In order to more clearly and completely illustrate the technical solution of the present invention, the present invention will be further described below with reference to the accompanying drawings.

[0031] Please refer to Figure 1 The present invention proposes a liquid hydrogen pump testing system based on a hydrogen liquefier, comprising a testing unit 2, a discharging unit 3 and a liquefaction unit 1, wherein:

[0032] The test unit 2 includes a cold box 21, a liquid hydrogen storage tank 22 disposed inside the cold box 21, a self-pressurizing vaporizer 23 disposed outside the cold box 21, a first liquid hydrogen pool 24, and a second liquid hydrogen pool 25. The two ends of the self-pressurizing vaporizer 23 are respectively connected to the outlet end at the bottom and the inlet end at the top of the liquid hydrogen storage tank 22. A submersible pump is installed in the first liquid hydrogen pool 24, and a high-pressure pump is installed in the second liquid hydrogen pool 25.

[0033] The liquefaction unit 1 includes a liquefier 11 and a compressor 12. The outlet end of the top of the liquid hydrogen storage tank 22 is connected to the compressor 12 and the liquefier 11 in sequence, and then connected back to the inlet end of the top of the liquid hydrogen storage tank 22.

[0034] The dispersing unit 3 includes a low-pressure vaporizer 31 and a high-pressure vaporizer 32. The outlet of the low-pressure vaporizer 31 is connected to a flame arrester and a low-pressure discharge pipe 34 in sequence, and the outlet of the high-pressure vaporizer 32 is connected to another flame arrester and a high-pressure discharge pipe 35 in sequence.

[0035] Two branches at one outlet end of the top of the liquid hydrogen storage tank 22 are connected to the top gas return ports of the first liquid hydrogen pool 24 and the second liquid hydrogen pool 25 respectively;

[0036] The three branches at the bottom outlet end of the liquid hydrogen storage tank 22 are respectively connected to the liquid inlet of the submersible pump in the first liquid hydrogen pool 24, the inlet end of the low-pressure vaporizer 31 and the liquid inlet of the high-pressure pump in the second liquid hydrogen pool 25. The liquid outlet of the submersible pump in the first liquid hydrogen pool 24 is connected to the first liquid hydrogen pool 24. A branch at the outlet end of the first liquid hydrogen pool 24 is connected to another bottom outlet end of the bottom of the liquid hydrogen storage tank 22. Another branch at the outlet end of the first liquid hydrogen pool 24 is connected to the inlet end of the low-pressure vaporizer 31 and the outlet end of the high-pressure pump in the second liquid hydrogen pool 25 is connected to the second liquid hydrogen pool 25. The outlet end of the second liquid hydrogen pool 25 is respectively connected to the inlet end of the high-pressure vaporizer 32 and the high-pressure discharge pipe 35.

[0037] In this embodiment:

[0038] The liquefier 11 is used to provide liquid hydrogen;

[0039] The compressor 12 is used to pressurize the boil-off gas and unliquefied hydrogen from the liquid hydrogen container and return them to the hydrogen liquefier for re-liquefaction;

[0040] The cold box 21 is used to provide a vacuum environment;

[0041] The self-pressurizing vaporizer 23 is used to adjust the pressure of the liquid hydrogen storage tank 22;

[0042] The liquid hydrogen storage tank 22 is used to store liquid hydrogen and provide testing working fluid;

[0043] The first liquid hydrogen tank 24 is used to provide a test environment for the submersible pump;

[0044] The second liquid hydrogen tank 25 is used to provide a test environment for the high-pressure pump;

[0045] The low-pressure vaporizer 31 is used to discharge liquid hydrogen and reheat the evaporated gas from the liquid hydrogen container;

[0046] The high-pressure vaporizer 32 is used to vaporize high-pressure liquid hydrogen;

[0047] Flame arresters are used to prevent sparks from causing explosions;

[0048] In a specific embodiment, the vacuum environment of the cold box 21 provides an insulating space. At the same time, the first liquid hydrogen pool 24 and the second liquid hydrogen pool 25 are also arranged in a vacuum environment to avoid heat leakage. The submersible pump is installed in the first liquid hydrogen pool 24, and the high-pressure pump is installed in the second liquid hydrogen pool 25. External pipes are connected to the submersible pump liquid inlet and the high-pressure pump liquid inlet respectively. Then the submersible pump liquid outlet and the high-pressure pump liquid inlet are connected to the first liquid hydrogen pool 24 and the second liquid hydrogen pool 25. The first liquid hydrogen pool 24 and the second liquid hydrogen pool 25 are then connected to other parts through the outlet end. By connecting in this way, the liquid hydrogen in the first liquid hydrogen pool 24 and the second liquid hydrogen pool 25 will completely immerse the submersible pump and the high-pressure pump. At the same time, the high-pressure pump and the submersible pump will also drive the liquid Hydrogen flows and is tested. The outlet and inlet ends of the liquid hydrogen storage tank 22, the first liquid hydrogen pool 24, the second liquid hydrogen pool 25, the low-pressure vaporizer 31, and the high-pressure vaporizer 32 are all provided with pressure sensors (P01-P09 in the figure), temperature sensors (T01-T09 in the figure), liquid level gauges (L1-L3 in the figure), etc., to detect the real-time status of each component. The self-pressurizing vaporizer 23 is connected to both ends of the liquid hydrogen storage tank 22. When the pressure is too low, the liquid hydrogen is converted into hydrogen gas through the self-pressurizing vaporizer 23 to increase the pressure to maintain the stable pressure of the liquid hydrogen storage tank 22. The high-pressure vaporizer 32 is used to vaporize and reheat the high-pressure liquid hydrogen at the outlet of the high-pressure pump, and the low-pressure vaporizer 31 is used to vaporize and reheat the low-pressure liquid hydrogen. The cold energy of the liquid hydrogen can be recovered;

[0049] When testing the high-pressure pump, the gas in all pipelines is replaced multiple times. After the impurity gas content in the system is reduced to meet the requirements, the liquefier 11 provides liquid hydrogen to the liquid hydrogen storage tank 22. The hydrogen that has not been converted into liquid hydrogen is pressurized by the compressor 12 and then enters the liquefier 11 again to be liquefied and converted into liquid hydrogen and enter the liquid hydrogen storage tank 22. The liquid hydrogen storage tank 22 is pre-cooled and filled with liquid hydrogen. Before the test process, part of the hydrogen enters the first liquid hydrogen pool 24 and the second liquid hydrogen pool 25 through the return port. Pre-cooling is performed to facilitate subsequent liquid hydrogen filling. The liquid hydrogen then passes through the submersible pump inlet, the submersible pump outlet, and the second liquid hydrogen pool 25 in sequence until the liquid hydrogen in the second liquid hydrogen pool 25 completely immerses the high-pressure pump. Different parameters of the high-pressure pump are then set to complete the test. The tested liquid hydrogen is reheated by the high-pressure vaporizer 32 and finally discharged to the high-pressure discharge pipe 35 after being depressurized. When the high-pressure pump outlet pressure is too high, the hydrogen will be directly depressurized and discharged to the high-pressure discharge pipe 35 through another branch at the high-pressure pump outlet.

[0050] When testing the submersible pump, the submersible pump pipeline and the first liquid hydrogen pool 24 are first purged with nitrogen and an airtightness test is performed. The low-pressure fluid is naturally circulated and pre-cooled between the liquid inlet of the submersible pump, the return port of the first liquid hydrogen pool 24, and the liquid hydrogen storage tank 22, and then circulated through the liquid outlet of the first liquid hydrogen pool 24. Different parameters of the submersible pump are set to complete the test. When the pressure of the loop exceeds a certain value, part of the hydrogen or liquid hydrogen will be discharged through another branch at the outlet of the first liquid hydrogen pool 24 to the low-pressure vaporizer 31 for vaporization and reheating, and finally discharged to the low-pressure discharge pipe 34;

[0051] The present invention uses different pipelines to test the submersible pump and the high-pressure pump separately, and finally discharges the hydrogen into the low-pressure discharge pipe 34 and the high-pressure discharge pipe 35. This is safer and can better discharge hydrogen. Using a cycle to test the submersible pump and the high-pressure pump can also save hydrogen energy and avoid waste.

[0052] In one embodiment, the entire system can meet the pump performance and critical NPSH test requirements in a low temperature environment of not less than 20K, especially in a 20K liquid hydrogen or 77K liquid nitrogen environment, to test the liquid hydrogen pump.

[0053] In one embodiment, the present invention divides the entire system into multiple modules, and each system component is modularized to facilitate disassembly, assembly, and maintenance.

[0054] Furthermore, it also includes a first regulating valve 13 and a second regulating valve 14. The first regulating valve 13 is arranged between the liquid hydrogen storage tank 22 and the outlet end of the liquefier 11, and the second regulating valve 14 is arranged between the inlet end of the compressor 12 and the top inlet of the liquid hydrogen storage tank 22.

[0055] In this embodiment:

[0056] The first regulating valve 13 and the second regulating valve 14 are used to control the on-off of the liquefaction unit 1 and the test unit 2;

[0057] In a specific embodiment, when the first regulating valve 13 and the second regulating valve 14 are opened, the hydrogen in the liquid hydrogen storage tank 22 passes through the second regulating valve 14 and the compressor 12 in sequence. After being compressed by the compressor 12, it is further cooled by the liquefier 11 and converted into liquid hydrogen and enters the liquid hydrogen storage tank 22.

[0058] Furthermore, it also includes a third regulating valve 27 and a fourth regulating valve. The third regulating valve 27 is arranged on the pipeline from the liquid hydrogen storage tank 22 to the outside, and the fourth regulating valve 28 is arranged between the liquid hydrogen storage tank 22 and the inlet end of the self-pressurizing vaporizer 23.

[0059] In this embodiment:

[0060] The third regulating valve 27 connects the liquid hydrogen storage tank 22 with the outside;

[0061] The fourth regulating valve is used to adjust the on / off of the self-pressurizing carburetor 23;

[0062] In a specific embodiment, the third regulating valve 27 is connected to the outside to facilitate the introduction of nitrogen to remove impurity gases in the entire system, and the fourth regulating valve controls the on and off of the self-pressurizing vaporizer 23 to control the pressure regulation of the liquid hydrogen storage tank 22 by the self-pressurizing vaporizer 23.

[0063] Furthermore, it also includes a fifth regulating valve 29 and a sixth regulating valve 210. The fifth regulating valve 29 is arranged between the return air port of the first liquid hydrogen pool 24 and the top of the liquid hydrogen storage tank 22, and the sixth regulating valve 210 is arranged between the return air port of the second liquid hydrogen pool 25 and the top of the liquid hydrogen storage tank 22.

[0064] In this embodiment:

[0065] The fifth regulating valve 29 and the sixth regulating valve 210 are used to control the discharge of hydrogen from the first liquid hydrogen pool 24 and the second liquid hydrogen pool 25;

[0066] In a specific embodiment, the hydrogen in the liquid hydrogen storage tank 22 enters the second liquid hydrogen pool 25 through the sixth regulating valve 210 for pre-cooling. After the pre-cooling is completed, the sixth regulating valve 210 is closed to add liquid hydrogen. The utilization rate of liquid hydrogen can be improved by hydrogen pre-cooling.

[0067] Furthermore, it also includes a first valve group 218, a second valve group 217 and a seventh regulating valve 216. The two ends of the first valve group 218 are respectively connected to the liquid outlet of the first liquid hydrogen pool 24 and the inlet of the low-pressure vaporizer 31, the two ends of the second valve group 217 are respectively connected to the return air port of the second liquid hydrogen pool 25 and the inlet of the low-pressure vaporizer 31, and the two ends of the seventh regulating valve 216 are respectively connected to the return air port of the first liquid hydrogen pool 24 and the inlet of the low-pressure vaporizer 31.

[0068] In this embodiment:

[0069] The first valve group 218 is used to control the connection between the liquid outlet of the first liquid hydrogen pool 24 and the low-pressure vaporizer 31;

[0070] The second valve group 217 is used to control the connection between the return port of the second liquid hydrogen pool 25 and the low-pressure vaporizer 31;

[0071] The seventh regulating valve 216 is used to control the flow between the gas return port of the first liquid hydrogen pool 24 and the low-pressure vaporizer 31;

[0072] In a specific embodiment, when the pressure at the liquid outlet or the return gas outlet of the first liquid hydrogen pool 24 is too high, the first valve group 218 or the seventh regulating valve 216 can be opened respectively to discharge part of the hydrogen to reduce the pressure. The hydrogen will pass through the first valve group 218 or the seventh valve group into the low-pressure vaporizer 31. When the pressure at the return gas outlet of the second liquid hydrogen pool 25 is too high, the seventh regulating valve 216 can be opened to allow the hydrogen to enter the low-pressure vaporizer 31. Finally, after the low-pressure vaporizer 31 is reheated, it enters the low-pressure discharge pipe 34 for discharge.

[0073] Furthermore, it also includes an eighth regulating valve 211, a ninth regulating valve 214, a first one-way valve 215 and a liquid hydrogen flowmeter 219. The first branch at the bottom outlet end of the liquid hydrogen storage tank 22 is connected in sequence to the eighth regulating valve 211 and the liquid inlet of the submersible pump, and is connected in sequence from the outlet end of the submersible pump to the first liquid hydrogen pool 24, the liquid hydrogen flowmeter 219, the ninth regulating valve 214, the first one-way valve 215 and the other bottom outlet end of the liquid hydrogen storage tank 22.

[0074] In this embodiment:

[0075] The eighth regulating valve 211 is used to regulate the on-off and flow rate of the liquid hydrogen storage tank 22 to the liquid inlet of the submersible pump;

[0076] The ninth regulating valve 214 is used to regulate the on-off and flow between the outlet of the first liquid hydrogen pool 24 and the liquid hydrogen storage tank 22;

[0077] The first one-way valve 215 is used to prevent the liquid hydrogen in the liquid hydrogen storage tank 22 from flowing into the first liquid hydrogen pool 24 from the outlet end of the first liquid hydrogen pool 24;

[0078] The liquid hydrogen flow meter 219 is used to detect the flow rate at the outlet of the first liquid hydrogen pool 24;

[0079] In a specific embodiment, liquid hydrogen flows out from the bottom of the liquid hydrogen storage tank 22 and passes through the eighth regulating valve 211, the submersible pump, and the first liquid hydrogen pool 24 in sequence. After the test is completed, it flows back into the liquid hydrogen storage tank 22 again. The liquid hydrogen pump is tested using a liquid hydrogen circulation loop, which can reduce liquid hydrogen loss.

[0080] Furthermore, it also includes a tenth regulating valve 213 and a second one-way valve 312. The second branch at the bottom outlet end of the liquid hydrogen storage tank 22 is connected to the tenth regulating valve 213, the low-pressure vaporizer 31, the flame arrester, the second one-way valve 312 and the low-pressure discharge pipe 34 in sequence.

[0081] In this embodiment:

[0082] The tenth regulating valve 213 is used to control the on-off and flow regulation between the inlet of the low-pressure vaporizer 31 and the liquid hydrogen storage tank 22, and is interlocked with the temperature sensor T09;

[0083] The second one-way valve 312 is used to prevent the low-pressure hydrogen from flowing back;

[0084] In a specific embodiment, after the test is completed, the tenth regulating valve 213 is opened, and the remaining liquid hydrogen in the liquid hydrogen storage tank 22 or when the liquid hydrogen in the liquid hydrogen storage tank 22 is too high, the liquid hydrogen passes through the tenth regulating valve 213, the low-pressure vaporizer 31, the flame arrester and the second one-way valve 312 in sequence. After the low-pressure vaporizer 31 vaporizes and reheats to recover the cold energy, it is discharged into the low-pressure discharge pipe 34 for release.

[0085] Furthermore, it also includes an eleventh regulating valve 212, a liquid hydrogen filter 26, a twelfth regulating valve 37 and a third one-way valve 38. The third branch at the bottom outlet end of the liquid hydrogen storage tank 22 is connected in sequence to the eleventh regulating valve 212, the liquid hydrogen filter 26 and the liquid inlet of the high-pressure pump in the second liquid hydrogen pool 25, and is connected in sequence from the outlet end of the second liquid hydrogen pool 25 to the twelfth regulating valve 37, the third one-way valve 38 and the high-pressure vaporizer 32.

[0086] In this embodiment:

[0087] The eleventh regulating valve 212 is used to control the on-off and flow regulation between the liquid inlet of the high-pressure pump and the liquid hydrogen storage tank 22;

[0088] The liquid hydrogen filter 26 is used to filter impurity gases and remove foam to improve the purity of liquid hydrogen;

[0089] The twelfth regulating valve 37 is used to control the flow between the outlet of the liquid hydrogen pool and the inlet of the high-pressure vaporizer 32;

[0090] The third one-way valve 38 is used to prevent the backflow of hydrogen in the high-pressure vaporizer 32;

[0091] In a specific embodiment, the liquid hydrogen in the liquid hydrogen storage tank 22 passes through the eleventh regulating valve 212 and enters the liquid hydrogen filter 26 to filter out impurities, then enters the high-pressure pump and the second liquid hydrogen pool 25, and finally enters the high-pressure vaporizer 32 from the outlet end of the liquid hydrogen pool through the twelfth regulating valve 37 and the third one-way valve 38 in sequence, and then is reheated and converted into hydrogen through the high-pressure vaporizer 32.

[0092] Furthermore, it also includes a gas flow meter 36, a thirteenth regulating valve 39, a fourteenth regulating valve 310, a pressure reducing valve 311, and a fourth one-way valve 313. The outlet end of the high-pressure vaporizer 32 is connected to the gas flow meter 36, the thirteenth regulating valve 39, the fourteenth regulating valve 310, the pressure reducing valve 311, the flame retardant 33, the fourth one-way valve 313 and the high-pressure discharge pipe 35 in sequence.

[0093] In this embodiment:

[0094] Gas flow meter 36 is used to detect high pressure hydrogen flow

[0095] The thirteenth regulating valve 39 and the fourteenth regulating valve 310 are used to control the opening and closing of the outlet of the high-pressure vaporizer 32;

[0096] The pressure reducing valve 311 is used to reduce the hydrogen pressure;

[0097] The fourth one-way valve 313 is used to prevent hydrogen from flowing back;

[0098] In a specific embodiment, the hydrogen at the outlet end of the high-pressure vaporizer 32 passes through the flow meter, the thirteenth regulating valve 39, the fourteenth regulating valve 310 in sequence, and then under the reduced pressure of the pressure reducing valve 311, passes through the flame retardant 33 and the fourth one-way valve 313 in sequence and is discharged into the high-pressure discharge pipe 35.

[0099] Furthermore, it also includes a third valve group 314, a fourth valve group 315 and a fifth valve group 316. The two ends of the third valve group 314 are respectively connected to the pipeline between the second liquid hydrogen pool 25 and the high-pressure discharge pipe 35 and the inlet end of the second regulating valve, the two ends of the fourth valve group 315 are respectively connected to the pipeline between the second liquid hydrogen pool 25 and the high-pressure discharge pipe 35 and the outlet end of the high-pressure vaporizer 32, and the two ends of the fifth valve group 316 are respectively connected to the pipeline between the second liquid hydrogen pool 25 and the high-pressure discharge pipe 35 and the inlet end of the fourteenth regulating valve 310.

[0100] In this embodiment:

[0101] The third valve group 314 and the fourth valve group 315 are used to control the pressure at the inlet and outlet of the high-pressure vaporizer 32 respectively;

[0102] The fifth valve group 316 is used to control the pressure at the inlet end of the pressure reducing valve 311;

[0103] In a specific embodiment, one outlet end of the second liquid hydrogen pool 25 is connected to the high-pressure discharge pipe 35 through the third valve group 314 to form a bypass branch, and the bypass branch is connected to the outlet end of the high-pressure vaporizer 32 and the inlet end of the pressure reducing valve 311 through the fourth valve group 315 and the fifth valve group 316 respectively. When the pressure in the branch where the high-pressure vaporizer 32 is located is too high, the third valve group 314, the fourth valve group 315 and the fifth valve group 316 will be opened respectively according to the actual pressure situation to directly discharge some gas into the high-pressure discharge pipe 35 to ensure the safety of the branch where the high-pressure vaporizer 32 is located.

[0104] In one embodiment, the first valve group 218, the second valve group 217, the third valve group 314 and the fourth valve group 315 each include a safety valve and two stop valves, while the fifth valve group 316 only has one safety valve and one stop valve. A manual stop valve is provided in front of the safety valve to facilitate replacement, disassembly and maintenance. Special working conditions can prevent the safety valve from tripping and keep it fully open during operation. The other stop valve is pneumatically controlled to prevent the closed section of the pipeline from being pressurized, thereby protecting the pipeline and components such as the carburetor.

[0105] In summary, when testing a high-pressure pump, the following steps are included:

[0106] First, the hydrogen liquefier 11 is turned on, and the liquefier 11 performs refrigeration and cooling. The generated cold hydrogen first enters the liquid hydrogen storage tank 22 through the first regulating valve 13 to cool the inside of the liquid hydrogen storage tank 22. After the temperature drops to the point where the liquefier 11 produces liquid hydrogen, the pre-cooling ends, and then the liquefier 11 starts to produce liquid hydrogen. The liquid hydrogen is filled into the liquid hydrogen storage tank 22 until the rated filling volume (wherein the liquid level gauge L01, temperature sensor T01 and pressure sensor P01 on the liquid hydrogen storage tank 22 are used to detect the real-time status of the liquid hydrogen storage tank 22. The hydrogen in the liquid hydrogen storage tank 22 returns to the liquefier 11 through the compressor 12 and is liquefied again. When the liquid level in the liquid hydrogen storage tank 22 is too high, part of the liquid hydrogen in the liquid hydrogen storage tank 22 enters the low-pressure vaporizer 31 through the tenth regulating valve 213 to be vaporized, and finally discharged to the low-pressure discharge pipe 34 and connected to the discharge tower for discharge).

[0107] After completing multiple replacements of the gas in the entire pipeline, and after the impurity content in the system is reduced to meet the requirements, the system is maintained at a residual pressure of approximately 0.15 MPa. The sixth regulating valve 210 is opened, and the low-temperature saturated hydrogen at the top of the liquid hydrogen storage tank 22 is used to pre-cool the entire high-pressure pump and the branch line where it is located.

[0108] After pre-cooling is completed, the sixth valve is closed, and the eleventh regulating valve 212, the twelfth regulating valve 37, and the third one-way valve 38 are opened to maintain the liquid level in the second liquid hydrogen pool 25 at 90% of the liquid hydrogen pool. The frequency of the high-pressure pump is set so that the high-pressure liquid hydrogen output by the high-pressure pump enters the high-pressure vaporizer 32. When the pressure at the outlet of the high-pressure pump reaches a first preset value (collected by the pressure sensor P3), the high-pressure pump is turned off, and finally the valve is opened to release the hydrogen into the high-pressure discharge pipe 35. Finally, different frequencies of the high-pressure pump are set and the output pressure of the high-pressure pump at different frequencies is repeatedly tested to complete the test;

[0109] When testing a low pressure submersible pump, the following steps are involved:

[0110] First, the nitrogen submersible pump pipeline and the pipeline of the first liquid hydrogen tank 24 are purged, and then the ninth regulating valve 214 is kept closed. The low-pressure fluid passes through the eighth regulating valve 211, the submersible pump, and the sixth regulating valve 210 from the liquid hydrogen storage tank 22 in sequence and flows back to the liquid hydrogen storage tank 22 for natural circulation. The first liquid hydrogen tank 24 is gradually filled with liquid hydrogen. At the same time, the gas flows back to the storage tank from the return air pipeline. After the temperature sensor T09 on the return air pipe detects that the temperature is stable, open the ninth regulating valve 214, test the submersible pump, and perform a pump cavitation margin test on the submersible pump.

[0111] Of course, the present invention may have many other implementations. Based on this implementation, other implementations obtained by ordinary technicians in this field without any creative work are all within the scope of protection of the present invention.

Claims

1. A liquid hydrogen pump test system based on a hydrogen liquefier, characterized in that: It includes a test unit, a release unit and a liquefaction unit, in which: The test unit includes a cold box, a liquid hydrogen storage tank arranged inside the cold box, a self-pressurizing vaporizer arranged outside the cold box, a first liquid hydrogen pool and a second liquid hydrogen pool, wherein both ends of the self-pressurizing vaporizer are respectively connected to the outlet end at the bottom and the inlet end at the top of the liquid hydrogen storage tank, a submersible pump is installed in the first liquid hydrogen pool, and a high-pressure pump is installed in the second liquid hydrogen pool; The liquefaction unit includes a liquefier and a compressor, and the outlet end at the top of the liquid hydrogen storage tank is connected to the compressor and the liquefier in sequence, and then connected back to the inlet end at the top of the liquid hydrogen storage tank; The dissipation unit includes a low-pressure vaporizer and a high-pressure vaporizer, wherein the outlet end of the low-pressure vaporizer is connected to a flame arrester and a low-pressure discharge pipe in sequence, and the outlet end of the high-pressure vaporizer is connected to another flame arrester and a high-pressure discharge pipe in sequence; Two branches at one outlet end of the top of the liquid hydrogen storage tank are connected to the top gas return ports of the first liquid hydrogen pool and the second liquid hydrogen pool respectively; The three branches at one bottom outlet end of the liquid hydrogen storage tank are respectively connected to the liquid inlet of the submersible pump in the first liquid hydrogen pool, the inlet end of the low-pressure vaporizer and the liquid inlet of the high-pressure pump in the second liquid hydrogen pool. The liquid outlet of the submersible pump in the first liquid hydrogen pool is connected to the first liquid hydrogen pool. One branch at the outlet end of the first liquid hydrogen pool is connected to another bottom outlet end of the bottom of the liquid hydrogen storage tank. Another branch at the outlet end of the first liquid hydrogen pool is connected to the inlet end of the low-pressure vaporizer. The outlet end of the high-pressure pump in the second liquid hydrogen pool is connected to the second liquid hydrogen pool. The outlet end of the second liquid hydrogen pool is respectively connected to the inlet end of the high-pressure vaporizer and the high-pressure discharge pipe.

2. The liquid hydrogen pump testing system based on a hydrogen liquefier according to claim 1, characterized in that: It also includes a first regulating valve and a second regulating valve. The first regulating valve is arranged between the liquid hydrogen storage tank and the outlet end of the liquefier, and the second regulating valve is arranged between the inlet end of the compressor and the top inlet of the liquid hydrogen storage tank.

3. The liquid hydrogen pump testing system based on a hydrogen liquefier according to claim 1, characterized in that: It also includes a third regulating valve and a fourth regulating valve. The third regulating valve is arranged on the pipeline from the liquid hydrogen storage tank to the outside, and the fourth regulating valve is arranged between the liquid hydrogen storage tank and the inlet end of the self-pressurizing vaporizer.

4. The liquid hydrogen pump testing system based on a hydrogen liquefier according to claim 1, characterized in that: It also includes a fifth regulating valve and a sixth regulating valve, the fifth regulating valve is arranged between the first liquid hydrogen pool return port and the top of the liquid hydrogen storage tank, and the sixth regulating valve is arranged between the second liquid hydrogen pool return port and the top of the liquid hydrogen storage tank.

5. The liquid hydrogen pump testing system based on a hydrogen liquefier according to claim 1, characterized in that: It also includes a first valve group, a second valve group and a seventh regulating valve, wherein two ends of the first valve group are respectively connected to the liquid outlet of the first liquid hydrogen pool and the inlet of the low-pressure vaporizer, two ends of the second valve group are respectively connected to the return gas port of the second liquid hydrogen pool and the inlet of the low-pressure vaporizer, and two ends of the seventh regulating valve are respectively connected to the return gas port of the first liquid hydrogen pool and the inlet of the low-pressure vaporizer.

6. The liquid hydrogen pump testing system based on a hydrogen liquefier according to claim 1, characterized in that: It also includes an eighth regulating valve, a ninth regulating valve, a first one-way valve and a liquid hydrogen flowmeter. The first branch at the bottom outlet end of the liquid hydrogen storage tank is connected in sequence to the eighth regulating valve and the liquid inlet of the submersible pump, and is connected in sequence from the outlet end of the submersible pump to the first liquid hydrogen pool, the liquid hydrogen flowmeter, the ninth regulating valve, the first one-way valve and the other bottom outlet end of the liquid hydrogen storage tank.

7. The liquid hydrogen pump testing system based on a hydrogen liquefier according to claim 6, characterized in that: It also includes a tenth regulating valve and a second one-way valve. The second branch at the bottom outlet end of the liquid hydrogen storage tank is connected to the tenth regulating valve, the low-pressure vaporizer, the flame arrester, the second one-way valve and the low-pressure exhaust pipe in sequence.

8. The liquid hydrogen pump testing system based on a hydrogen liquefier according to claim 7, characterized in that: It also includes an eleventh regulating valve, a liquid hydrogen filter, a twelfth regulating valve and a third one-way valve. The third branch at the bottom outlet end of the liquid hydrogen storage tank is connected in sequence to the eleventh regulating valve, the liquid hydrogen filter and the liquid inlet of the high-pressure pump in the second liquid hydrogen pool, and is connected in sequence from the outlet end of the second liquid hydrogen pool to the twelfth regulating valve, the third one-way valve and the high-pressure vaporizer.

9. The liquid hydrogen pump testing system based on a hydrogen liquefier according to claim 8, characterized in that: It also includes a gas flow meter, a thirteenth regulating valve, a fourteenth regulating valve, a pressure reducing valve, and a fourth one-way valve. The outlet end of the high-pressure vaporizer is connected to the gas flow meter, the thirteenth regulating valve, the fourteenth regulating valve, the pressure reducing valve, the flame retardant, the fourth one-way valve and the high-pressure discharge pipe in sequence.

10. The liquid hydrogen pump testing system based on a hydrogen liquefier according to claim 9, characterized in that: It also includes a third valve group, a fourth valve group and a fifth valve group, wherein two ends of the third valve group are respectively connected to the pipeline between the second liquid hydrogen pool and the high-pressure discharge pipe and the inlet end of the twelfth regulating valve, two ends of the fourth valve group are respectively connected to the pipeline between the second liquid hydrogen pool and the high-pressure discharge pipe and the outlet end of the high-pressure vaporizer, and two ends of the fifth valve group are respectively connected to the pipeline between the second liquid hydrogen pool and the high-pressure discharge pipe and the inlet end of the fourteenth regulating valve.

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