Gasification hydrogen recovery and pressure relief coupling system for liquid hydrogen storage

Abstract

The invention discloses a gasified hydrogen recovery and pressure relief coupling system for liquid hydrogen storage. The secondary heat exchanger and the primary heat exchanger are respectively provided with a cold side inlet, a cold side outlet, a hot side inlet and a hot side outlet; a hydrogen and air inlet and a tail gas outlet are formed in the auxiliary power device; a hydrogen and diluent gas inlet and a mixed gas outlet are formed in the mixed gas cylinder; a first liquid hydrogen pump in the liquid hydrogen storage tank is connected with the power device through a first one-way valve; a gas hydrogen outlet of the liquid hydrogen storage tank is connected with a hydrogen inlet of the mixed gas cylinder and an inlet of the hydrogen compressor, an outlet of the hydrogen compressor is connected with a cold side inlet of the secondary heat exchanger, and a cold side outlet of the secondary heat exchanger is connected with a hydrogen inlet of the auxiliary power device. An outlet of the air compressor is connected with a cold side inlet of the primary heat exchanger, and a cold side outlet of the primary heat exchanger is connected with an air inlet of the auxiliary power device. According to the liquid hydrogen storage tank, the situation that evaporation gas hydrogen in the liquid hydrogen storage tank is directly discharged to cause aircraft energy waste can be avoided, and meanwhile redundant evaporation gas hydrogen can be safely and reliably discharged to the external environment.

Description

Technical Field

[0001] The present invention belongs to the technical field of aircraft electromechanical systems, and in particular relates to a liquid hydrogen storage vaporized hydrogen recovery and pressure relief coupling system. Background Art

[0002] Developing sustainable aviation technologies, such as hydrogen fuel, biofuel, solar energy and other green energy to replace traditional aviation kerosene, and adopting electric aircraft, wing-body fusion and other advanced technologies are important ways for the aviation industry to achieve carbon reduction goals. Among them, hydrogen fuel has the advantages of wide sources, high energy utilization rate and pollution-free products, and is the main alternative energy source for future new energy.

[0003] Since the mass density of cryogenic liquid hydrogen is several times that of high-pressure gaseous hydrogen, and the mass of liquid hydrogen storage tanks is lower than that of high-pressure gaseous hydrogen, it is the preferred hydrogen storage solution for future civil aircraft. Cryogenic liquid hydrogen needs to be stored in a deep cold environment of -253°C. Due to the high ambient temperature, the liquid hydrogen storage tank will inevitably absorb a certain amount of ambient heat during flight, causing part of the liquid hydrogen inside the tank to absorb heat and vaporize. In order to prevent the internal pressure of the liquid hydrogen storage tank from exceeding the safety pressure, the excess evaporated hydrogen needs to be discharged to maintain the internal pressure of the liquid hydrogen storage tank stable. However, this method has the following disadvantages:

[0004] On the one hand, direct discharge of evaporated hydrogen into the external environment will cause a waste of aircraft energy. On the other hand, the combustion and explosion limits of hydrogen can reach 4-75%. Within this concentration range, even very small static electricity, sparks, etc. may cause combustion and explosion. Therefore, directly discharged hydrogen gas, after mixing with the surrounding air, will pose a serious threat to the safety of the aircraft. Summary of the invention

[0005] The purpose of the present invention is to provide a liquid hydrogen storage vaporized hydrogen recovery and pressure relief coupling system. The present invention can avoid direct discharge of evaporated hydrogen in the liquid hydrogen storage tank causing waste of aircraft energy, while the excess evaporated hydrogen can be safely and reliably discharged to the external environment.

[0006] The technical solution of the present invention is: a gasified hydrogen recovery and pressure relief coupling system for liquid hydrogen storage, comprising a liquid hydrogen storage tank, a first liquid hydrogen pump, a first one-way valve, a power unit, a hydrogen compressor, a secondary heat exchanger, an air compressor, a primary heat exchanger, an auxiliary power unit, a mixed gas cylinder, and a safety pressure relief valve;

[0007] Among them, the secondary heat exchanger and the primary heat exchanger are both provided with a cold side inlet, a cold side outlet, a hot side inlet, and a hot side outlet; the auxiliary power unit is provided with a hydrogen inlet, an air inlet, and an exhaust gas outlet; the mixed gas cylinder is provided with a hydrogen inlet, a diluent gas inlet, and a mixed gas outlet;

[0008] The first liquid hydrogen pump and the first one-way valve are placed inside the liquid hydrogen storage tank, the outlet of the first liquid hydrogen pump is connected to the inlet of the first one-way valve, and the outlet of the first one-way valve is connected to the power device;

[0009] The gas hydrogen outlet of the liquid hydrogen storage tank is connected to the first side of the first three-way pipe, the second side of the first three-way pipe is connected to the hydrogen inlet of the mixed gas bottle, the third side of the first three-way pipe is connected to the inlet of the hydrogen compressor, the hydrogen compressor outlet is connected to the cold side inlet of the secondary heat exchanger, the cold side outlet of the secondary heat exchanger is connected to the hydrogen inlet of the auxiliary power unit; the outlet of the air compressor is connected to the cold side inlet of the primary heat exchanger, and the cold side outlet of the primary heat exchanger is connected to the air inlet of the auxiliary power unit;

[0010] The mixed gas outlet of the auxiliary power unit is connected to the hot side inlet of the primary heat exchanger, and the hot side outlet of the primary heat exchanger is connected to the hot side inlet of the secondary heat exchanger; the dilution gas inlet of the mixed gas bottle is connected to the dilution gas source providing the dilution gas, and the mixed gas outlet of the mixed gas bottle is connected to the safety pressure relief valve.

[0011] In the aforementioned liquid hydrogen storage gasified hydrogen recovery and pressure relief coupling system, the dilution gas source is a secondary heat exchanger; the hot side outlet of the secondary heat exchanger is connected to the dilution gas inlet of the mixed gas bottle.

[0012] In the aforementioned liquid hydrogen storage gasified hydrogen recovery and pressure relief coupling system, the dilution gas source is an air compressor; the outlet of the air compressor is also connected to the dilution gas inlet of the mixed gas bottle.

[0013] In the aforementioned liquid hydrogen storage gasified hydrogen recovery and pressure relief coupling system, the dilution gas source is ram air from the aircraft; the ram air bleed outlet is connected to the dilution gas inlet of the mixed gas bottle.

[0014] In the aforementioned liquid hydrogen storage vaporized hydrogen recovery and pressure relief coupling system, a pressure regulating valve is provided between the dilution gas inlet of the mixed gas bottle and the dilution gas source. The pressure regulating valve can adjust the dilution gas pressure entering the mixed gas bottle according to the pressure relief pressure and the maximum safety pressure of the pressure relief system to prevent the dilution gas pressure entering from being too high, thereby inhibiting the discharge of evaporated hydrogen at the outlet of the liquid hydrogen storage tank and causing abnormal pressure inside the liquid hydrogen storage tank.

[0015] The aforementioned liquid hydrogen storage gasification hydrogen recovery and pressure relief coupling system also includes a second liquid hydrogen pump, a second one-way valve, a second liquid hydrogen pump, and the second one-way valve is placed inside the liquid hydrogen storage tank. The outlet of the second liquid hydrogen pump is connected to the inlet of the second one-way valve; the outlet of the first one-way valve is connected to the first side of the second three-way pipe, the outlet of the second one-way valve is connected to the second side of the second three-way pipe, and the third side of the second three-way pipe is connected to the power unit. Among them, the second liquid hydrogen pump and the second one-way valve are backups of the first liquid hydrogen pump and the first one-way valve. When the first liquid hydrogen pump fails or fails and cannot normally deliver hydrogen fuel to the propulsion system, the second liquid hydrogen pump starts to run to ensure that the liquid hydrogen fuel in the liquid hydrogen storage tank is stably and reliably delivered to the power unit, thereby improving the reliability of the system.

[0016] The aforementioned liquid hydrogen storage vaporized hydrogen recovery and pressure relief coupling system also includes a stop valve, the gas hydrogen outlet of the liquid hydrogen storage tank is connected to the stop valve inlet, and the stop valve outlet is connected to the first side of the first three-way pipe. The stop valve can cut off the delivery of evaporated gas hydrogen in time in emergency situations such as system failure or leakage, preventing the system from operating under abnormal conditions or continuous leakage, which affects the flight safety of the aircraft.

[0017] The aforementioned liquid hydrogen storage gasified hydrogen recovery and pressure relief coupling system also includes a first one-way valve and a second one-way valve; the outlet of the stop valve is connected to the inlet of the first one-way valve, and the outlet of the first one-way valve is connected to the first side of the first three-way pipe; the second side of the first three-way pipe is connected to the inlet of the second one-way valve, and the outlet of the second one-way valve is connected to the hydrogen inlet of the mixed gas bottle. The first one-way valve is unidirectional, which can prevent the compressed hydrogen from flowing back to the liquid hydrogen storage tank when the hydrogen compressor fails; the second one-way valve can prevent the mixed gas from flowing back to the liquid hydrogen storage tank or the inlet of the hydrogen compressor when the internal pressure of the mixed gas bottle is too high.

[0018] The advantages of the present invention are: the gasified hydrogen recovery and pressure relief coupling system of the liquid hydrogen storage of the present invention pressurizes part of the gaseous hydrogen evaporated by the liquid hydrogen storage tank and supplies it to the auxiliary power unit for use, and the excess part is fully mixed with the exhaust gas of the auxiliary power unit to below the lower limit of hydrogen combustion and explosion, and then safely discharged to the external environment; it avoids the direct discharge of evaporated hydrogen in the liquid hydrogen storage tank to cause waste of aircraft energy, and at the same time, the excess evaporated hydrogen can be safely and reliably discharged to the external environment. Specifically, the present invention has the following technical advantages:

[0019] 1. The present invention supplies the gaseous hydrogen evaporated by absorbing heat in the liquid hydrogen storage tank to the auxiliary power unit after being pressurized, which can greatly reduce the energy waste and environmental pollution caused by direct discharge of evaporated gaseous hydrogen to the external environment, thereby improving the energy utilization rate of the aircraft;

[0020] 2. The present invention uses the exhaust gas of the auxiliary power unit to mix with the hydrogen that needs to be discharged by the pressure relief system to reduce the hydrogen concentration to below the lower limit of the flammable limit, so that even if there is an ignition source such as static electricity or sparks, it will not cause combustion and explosion, and can be safely and reliably discharged to the external environment;

[0021] 3. The evaporated hydrogen in the liquid hydrogen storage tank of the present invention can be recycled and safely discharged, so the insulation performance requirements of the liquid hydrogen storage tank can be greatly reduced. The design of the liquid hydrogen storage tank can balance the relationship between weight and heat absorption rate. Figure 4 It can be seen that lowering the insulation performance requirements can effectively reduce the weight of the liquid hydrogen storage tank, making the design of the liquid hydrogen storage system more flexible. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of a gasified hydrogen recovery and pressure relief coupling system for liquid hydrogen storage of the present invention;

[0023] Figure 2 It is a schematic diagram of a gasified hydrogen recovery and pressure relief coupling system for liquid hydrogen storage using compressed air as a diluent gas according to the present invention;

[0024] Figure 3 It is a schematic diagram of a gasified hydrogen recovery and pressure relief coupling system for liquid hydrogen storage using ram air as a diluent gas according to the present invention;

[0025] Figure 4 This is the relationship curve between the weight of the liquid hydrogen storage tank and the heat absorption rate.

[0026] Among them, 1-liquid hydrogen storage tank, 2-first liquid hydrogen pump, 3-first one-way valve, 4-second liquid hydrogen pump, 5-second one-way valve, 6-power unit, 7-stop valve, 8-hydrogen compressor, 9-secondary heat exchanger, 10-air compressor, 11-primary heat exchanger, 12-auxiliary power unit, 13-pressure regulating valve, 14-mixing gas bottle, 15-safety pressure relief valve, 16-first one-way valve, 17-second one-way valve, 18-ram air bleed outlet. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] The features and illustrative embodiments of various aspects of the present invention will be described in detail below. In the detailed description below, many specific details are proposed to provide a comprehensive understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present invention by illustrating examples of the present invention. The present invention is by no means limited to any specific settings and methods proposed below, but covers any improvements, replacements and modifications of structures, methods, devices without departing from the spirit of the present invention. In the accompanying drawings and the following description, known structures and technologies are not shown to avoid unnecessary ambiguity in the present invention.

[0029] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other, and the embodiments can refer to and quote each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0030] Example 1. A liquid hydrogen storage gasification hydrogen recovery and pressure relief coupling system, comprising: Figure 1-3 As shown, it includes a liquid hydrogen storage tank 1, a first liquid hydrogen pump 2, a first one-way valve 3, a second liquid hydrogen pump 4, a second one-way valve 5, a power unit 6, a stop valve 7, a hydrogen compressor 8, a secondary heat exchanger 9, an air compressor 10, a primary heat exchanger 11, an auxiliary power unit 12, a pressure regulating valve 13, a mixed gas bottle 14, a safety pressure relief valve 15, a first one-way valve 16, and a second one-way valve 17. The secondary heat exchanger 9 is provided with a cold side inlet, a cold side outlet, a hot side inlet, and a hot side outlet; the primary heat exchanger 11 is provided with a cold side inlet, a cold side outlet, a hot side inlet, and a hot side outlet; the auxiliary power unit 12 is provided with a hydrogen inlet, an air inlet, and an exhaust gas outlet; the mixed gas bottle 14 is provided with a hydrogen inlet, a diluent gas inlet, and a mixed gas outlet.

[0031] The first liquid hydrogen pump 2 and the first one-way valve 3 are placed inside the liquid hydrogen storage tank 1, the outlet of the first liquid hydrogen pump 2 is connected to the inlet of the first one-way valve 3 through a pipeline, and the outlet of the first one-way valve 3 is connected to the power device 6 through a pipeline;

[0032] The gas hydrogen outlet of the liquid hydrogen storage tank 1 is connected to the first side of the first tee through a pipeline, the second side of the first tee is connected to the hydrogen inlet of the mixed gas bottle 14 through a pipeline, the third side of the first tee is connected to the inlet of the hydrogen compressor 8 through a pipeline, the outlet of the hydrogen compressor 8 is connected to the cold side inlet of the secondary heat exchanger 9 through a pipeline, and the cold side outlet of the secondary heat exchanger 9 is connected to the hydrogen inlet of the auxiliary power unit 12 through a pipeline; the outlet of the air compressor 10 is connected to the cold side inlet of the primary heat exchanger 11 through a pipeline, and the cold side outlet of the primary heat exchanger 11 is connected to the air inlet of the auxiliary power unit 12 through a pipeline;

[0033] The mixed gas outlet of the auxiliary power unit 12 is connected to the hot side inlet of the primary heat exchanger 11 through a pipeline, the hot side outlet of the primary heat exchanger 11 is connected to the hot side inlet of the secondary heat exchanger 9 through a pipeline, the hot side outlet of the secondary heat exchanger 9 is connected to the dilution gas inlet of the mixed gas bottle 14 through a pipeline, and the mixed gas outlet of the mixed gas bottle 14 is connected to the safety pressure relief valve 15 through a pipeline.

[0034] A gasified hydrogen recovery and pressure relief coupling system for liquid hydrogen storage also includes a second liquid hydrogen pump 4, a second one-way valve 5, and the second liquid hydrogen pump 4 and the second one-way valve 5 are placed inside a liquid hydrogen storage tank 1, the outlet of the second liquid hydrogen pump 4 is connected to the inlet of the second one-way valve 5 through a pipeline, the outlet of the first one-way valve 3 is connected to the first side of the second three-way pipe through a pipeline, the outlet of the second one-way valve 5 is connected to the second side of the second three-way pipe through a pipeline, and the third side of the second three-way pipe is connected to a power unit 6 through a pipeline; wherein the second liquid hydrogen pump 4 and the second one-way valve 5 are backups of the first liquid hydrogen pump 2 and the first one-way valve 3, and when the first liquid hydrogen pump 2 fails or fails and cannot normally deliver hydrogen fuel to the propulsion system, the second liquid hydrogen pump 4 starts to run to ensure that the liquid hydrogen fuel in the liquid hydrogen storage tank 1 is stably and reliably delivered to the power unit, thereby improving the reliability of the system.

[0035] A liquid hydrogen storage vaporized hydrogen recovery and pressure relief coupling system also includes a stop valve 7, wherein the gaseous hydrogen outlet of the liquid hydrogen storage tank 1 is connected to the inlet of the stop valve 7 through a pipeline, and the outlet of the stop valve 7 is connected to the first side of the first three-way pipe through a pipeline; the stop valve 7 can timely cut off the transmission of evaporated gaseous hydrogen in an emergency such as a system failure or leakage, thereby preventing the system from operating under abnormal conditions or continuous leakage, thereby affecting the flight safety of the aircraft.

[0036] A liquid hydrogen storage gasified hydrogen recovery and pressure relief coupling system also includes a pressure regulating valve 13, the hot side outlet of the secondary heat exchanger 9 is connected to the inlet of the pressure regulating valve 13 through a pipeline, and the outlet of the pressure regulating valve 13 is connected to the dilution gas inlet of the mixed gas bottle 14 through a pipeline; the pressure regulating valve 13 can adjust the pressure of the mixed gas at the outlet of the auxiliary power unit 12 according to the pressure relief pressure and the maximum safety pressure of the pressure relief system, to prevent the mixed gas pressure at the outlet of the auxiliary power unit 12 from being too high, inhibiting the discharge of evaporated hydrogen at the outlet of the liquid hydrogen storage tank 1, resulting in abnormal pressure inside the liquid hydrogen storage tank 1.

[0037] A gasified hydrogen recovery and pressure relief coupling system for liquid hydrogen storage, further comprising a first one-way valve 16 and a second one-way valve 17, wherein the outlet of the stop valve 7 is connected to the inlet of the first one-way valve 16 through a pipeline, and the outlet of the first one-way valve 16 is connected to the first side of the first three-way pipe through a pipeline; the second side of the first three-way pipe is connected to the inlet of the second one-way valve 17 through a pipeline, and the outlet of the second one-way valve 17 is connected to the hydrogen inlet of the mixed gas bottle 14 through a pipeline; the first one-way valve 16 is unidirectionally circulated, which can prevent the compressed hydrogen from flowing back to the liquid hydrogen storage tank 1 when the hydrogen compressor 8 fails; the second one-way valve 17 can prevent the mixed gas from flowing back to the liquid hydrogen storage tank 1 or the inlet of the hydrogen compressor 8 when the internal pressure of the mixed gas bottle 14 is too high;

[0038] The liquid hydrogen storage tank 1 is an insulated storage tank, and there are multiple layers between the inner and outer walls of the storage tank, including a high vacuum layer and an insulating material layer, respectively. The insulating material can be any one of insulating foam, aerogel, and composite insulating material;

[0039] The hydrogen compressor 8 is a compressor with adjustable speed, which can adjust the pressure of the evaporated hydrogen at the outlet of the liquid hydrogen storage tank 1 according to the pressure requirements of the auxiliary power unit 12 for the inlet hydrogen under different flight conditions, so as to make the auxiliary power unit 12 operate efficiently under the best working conditions;

[0040] The air compressor 10 is an electric compressor with adjustable flow and pressure, which adjusts the speed and outlet back pressure to achieve the flow and pressure required by the auxiliary power unit 1217;

[0041] The auxiliary power unit 1217 can be any one of a hydrogen fuel cell, a hydrogen internal combustion engine, and a hydrogen turbine engine. Among them, the use of hydrogen fuel cells has the advantages of high energy conversion rate and low noise, and can work continuously under the full flight envelope.

[0042] Embodiment 2: This embodiment uses the compressed air at the inlet of the fuel cell to fully mix with the exhausted evaporated hydrogen to reduce the hydrogen concentration of the exhaust gas. Figure 2 It can be seen that the difference between this embodiment and Example 1 is that the outlet of the hydrogen fuel cell 12 is directly discharged after passing through the primary heat exchanger 11 and the secondary heat exchanger 9, the outlet of the air compressor 10 is connected to the first side of the third tee through a pipeline, the second side of the second tee is connected to the inlet of the pressure regulating valve 13 through a pipeline, and the third side of the second tee is connected to the cold side inlet of the primary heat exchanger 11 through a pipeline.

[0043] The working process of this embodiment is as follows:

[0044] The high-temperature exhaust gas at the outlet of the hydrogen fuel cell 12 is directly discharged after heat exchange and cooling through the primary heat exchanger 11 and the secondary heat exchanger 9. A portion of the compressed air at the outlet of the air compressor 10 enters the mixed gas bottle 14 through the pressure regulating valve 13 to reduce the concentration of evaporated hydrogen in the mixed gas bottle 14, and a portion of the compressed air enters the auxiliary power unit 12 after heat exchange through the primary heat exchanger 11.

[0045] Embodiment 3: This embodiment uses ram air to fully mix with the exhausted evaporated hydrogen to reduce the hydrogen concentration of the exhaust gas. Figure 3 It can be seen that the difference between this embodiment and Example 1 is that the outlet of the hydrogen fuel cell 12 is directly emptied after passing through the primary heat exchanger 11 and the secondary heat exchanger 9, and the ram air bleed outlet 18 is connected to the inlet of the pressure regulating valve 13 through a pipeline.

[0046] The working process of this embodiment is as follows:

[0047] The high-temperature exhaust gas at the outlet of the hydrogen fuel cell 12 is directly discharged after heat exchange and cooling through the primary heat exchanger 11 and the secondary heat exchanger 9. The ram air at the ram air induction outlet 18 enters the mixed gas cylinder 14 after pressure regulation by the pressure regulating valve 13, thereby reducing the concentration of evaporated hydrogen in the mixed gas cylinder 14.

Claims

1. A gasified hydrogen recovery and pressure relief coupling system for liquid hydrogen storage, characterized in that: It comprises a liquid hydrogen storage tank (1), a first liquid hydrogen pump (2), a first one-way valve (3), a power unit (6), a hydrogen compressor (8), a secondary heat exchanger (9), an air compressor (10), a primary heat exchanger (11), an auxiliary power unit (12), a mixed gas cylinder (14), and a safety pressure relief valve (15); The secondary heat exchanger (9) and the primary heat exchanger (11) are both provided with a cold side inlet, a cold side outlet, a hot side inlet, and a hot side outlet; the auxiliary power unit (12) is provided with a hydrogen inlet, an air inlet, and an exhaust gas outlet; and the mixed gas bottle (14) is provided with a hydrogen inlet, a diluent gas inlet, and a mixed gas outlet; The first liquid hydrogen pump (2) and the first one-way valve (3) are placed inside the liquid hydrogen storage tank (1), the outlet of the first liquid hydrogen pump (2) is connected to the inlet of the first one-way valve (3), and the outlet of the first one-way valve (3) is connected to the power device (6); The gas hydrogen outlet of the liquid hydrogen storage tank (1) is connected to the first side of the first three-way pipe, the second side of the first three-way pipe is connected to the hydrogen inlet of the mixed gas bottle (14), the third side of the first three-way pipe is connected to the inlet of the hydrogen compressor (8), the outlet of the hydrogen compressor (8) is connected to the cold side inlet of the secondary heat exchanger (9), and the cold side outlet of the secondary heat exchanger (9) is connected to the hydrogen inlet of the auxiliary power unit (12); the outlet of the air compressor (10) is connected to the cold side inlet of the primary heat exchanger (11), and the cold side outlet of the primary heat exchanger (11) is connected to the air inlet of the auxiliary power unit (12); The mixed gas outlet of the auxiliary power unit (12) is connected to the hot side inlet of the primary heat exchanger (11), and the hot side outlet of the primary heat exchanger (11) is connected to the hot side inlet of the secondary heat exchanger (9); the dilution gas inlet of the mixed gas bottle (14) is connected to a dilution gas source that provides dilution gas, and the mixed gas outlet of the mixed gas bottle (14) is connected to a safety pressure relief valve (15).

2. The gasified hydrogen recovery and pressure relief coupling system for liquid hydrogen storage according to claim 1 is characterized in that: The dilution gas source is a secondary heat exchanger (9); the hot side outlet of the secondary heat exchanger (9) is connected to the dilution gas inlet of the mixed gas bottle (14).

3. The gasified hydrogen recovery and pressure relief coupling system for liquid hydrogen storage according to claim 1 is characterized in that: The dilution gas source is an air compressor (10); the outlet of the air compressor (10) is also connected to the dilution gas inlet of the mixed gas bottle (14).

4. The gasified hydrogen recovery and pressure relief coupling system for liquid hydrogen storage according to claim 1 is characterized in that: The dilution gas source is ram air from an aircraft; the ram air bleed outlet (18) is connected to the dilution gas inlet of the mixed gas bottle (14).

5. The gasified hydrogen recovery and pressure relief coupling system for liquid hydrogen storage according to claim 1 is characterized in that: A pressure regulating valve (13) is provided between the dilution gas inlet of the mixed gas cylinder (14) and the dilution gas source.

6. The gasified hydrogen recovery and pressure relief coupling system for liquid hydrogen storage according to claim 1 is characterized in that: The invention also comprises a second liquid hydrogen pump (4), a second one-way valve (5), the second liquid hydrogen pump (4), the second one-way valve (5) is arranged inside the liquid hydrogen storage tank (1), the outlet of the second liquid hydrogen pump (4) is connected to the inlet of the second one-way valve (5); the outlet of the first one-way valve (3) is connected to the first side of the second three-way pipe, the outlet of the second one-way valve (5) is connected to the second side of the second three-way pipe, and the third side of the second three-way pipe is connected to the power device (6).

7. The gasified hydrogen recovery and pressure relief coupling system for liquid hydrogen storage according to claim 1 is characterized in that: It also comprises a stop valve (7), the gas hydrogen outlet of the liquid hydrogen storage tank (1) is connected to the inlet of the stop valve (7), and the outlet of the stop valve (7) is connected to the first side of the first three-way pipe.

8. The gasified hydrogen recovery and pressure relief coupling system for liquid hydrogen storage according to claim 7, characterized in that: It also includes a first one-way valve (16) and a second one-way valve (17); the outlet of the stop valve (7) is connected to the inlet of the first one-way valve (16), and the outlet of the first one-way valve (16) is connected to the first side of the first three-way pipe; the second side of the first three-way pipe is connected to the inlet of the second one-way valve (17), and the outlet of the second one-way valve (17) is connected to the hydrogen inlet of the mixed gas bottle (14).

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