A liquid hydrogen filling system and method

Abstract

This invention provides a liquid hydrogen refueling system and method. The system includes a liquid hydrogen storage tank, a liquid hydrogen refueling pipeline, a liquid hydrogen circulation pipeline, and a liquid hydrogen circulation branch. One end of the liquid hydrogen refueling pipeline is connected to the liquid hydrogen storage tank, and the other end is connected to a refueling nozzle. A liquid hydrogen booster, an inlet valve, an inlet monitoring system, and a refueling pneumatic valve are installed on the liquid hydrogen refueling pipeline from the liquid hydrogen storage tank towards the refueling nozzle. One end of the liquid hydrogen circulation pipeline is connected to the liquid hydrogen storage tank, and the other end is connected to the refueling nozzle inlet. A circulation outlet valve and a first circulation pneumatic valve are installed on the liquid hydrogen circulation pipeline from the liquid hydrogen storage tank towards the refueling nozzle inlet. One end of the liquid hydrogen circulation branch is connected to the liquid hydrogen refueling pipeline, located between the inlet valve and the inlet monitoring system. The other end is connected to the liquid hydrogen circulation pipeline, located between the circulation outlet valve and the first circulation pneumatic valve. A second circulation pneumatic valve is installed on the liquid hydrogen circulation branch. This invention prevents excessive vaporization of liquid hydrogen during refueling, saves on the replacement process, and improves refueling efficiency.

Description

Technical Field

[0001] This invention relates to the field of hydrogenation equipment technology, and in particular to a liquid hydrogen refueling system and method. Background Technology

[0002] Hydrogen refueling stations are essential infrastructure that provides energy replenishment for hydrogen energy utilization equipment and facilities such as hydrogen fuel cell vehicles. They are a prerequisite for the promotion and application of hydrogen fuel cell vehicles and the accelerated development of the hydrogen energy industry. Generally, hydrogen refueling stations are divided into high-pressure hydrogen refueling stations and liquid hydrogen refueling stations. Compared with high-pressure hydrogen refueling stations, liquid hydrogen refueling stations have advantages such as high transportation efficiency, low storage and transportation pressure, high safety factor, small footprint, and high overall station storage efficiency. With the promotion of liquid hydrogen, liquid hydrogen refueling stations will become the mainstream.

[0003] Liquid hydrogen refueling stations are divided into liquid hydrogen storage stations and liquid hydrogen refueling stations. Liquid hydrogen storage stations store liquid hydrogen on-site and then vaporize it into high-pressure hydrogen gas before refueling. Liquid hydrogen refueling stations directly refuel vehicles with liquid hydrogen, which is vaporized in the onboard system. The challenges of liquid hydrogen refueling stations lie in the cryogenic insulation of the entire refueling system and the development of the refueling equipment. Currently, there are few mature liquid hydrogen refueling systems available domestically and internationally, making it difficult to meet the needs of station construction. With the development of new transportation vehicles such as liquid hydrogen heavy-duty trucks, the development of liquid hydrogen refueling systems suitable for civilian use is urgently needed.

[0004] Liquid hydrogen refueling systems are currently mainly used in the aerospace field. Compared with the civilian field, liquid hydrogen refueling systems in this field have the characteristics of large single refueling flow, simple operating parameters of the receiving container, more complex system, large space occupation, and inability to achieve fully automatic refueling, making them unsuitable for the civilian field.

[0005] In the civilian sector, there are relatively few liquid hydrogen refueling systems available both domestically and internationally. Internationally, the only known system is the liquid hydrogen refueling system developed by Linde for Daimler and BMW, primarily for heavy-duty trucks. This system suffers from severe heat leakage, generates a large amount of BOG (Boiler Air Gathering), has low refueling efficiency, and cannot adjust the refueling speed. Domestically, liquid hydrogen dispensers suitable for liquid hydrogen refueling stations are still in the experimental stage.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome at least some of the shortcomings of the prior art and provide a liquid hydrogen refueling system. By setting up liquid hydrogen circulation branch pipes and liquid hydrogen circulation pipelines, all pipelines are pre-cooled to prevent large amounts of liquid hydrogen from vaporizing during refueling, thereby improving refueling efficiency. Moreover, after refueling is completed, the liquid hydrogen circulation pipelines can be used to maintain the refueling state, saving the replacement process before refueling, simplifying the refueling process, and further improving refueling efficiency.

[0008] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is as follows:

[0009] A liquid hydrogen refueling system includes a liquid hydrogen storage tank, a liquid hydrogen refueling pipeline, a liquid hydrogen circulation pipeline, and a liquid hydrogen circulation branch;

[0010] One end of the liquid hydrogen filling pipeline is connected to the liquid hydrogen storage tank, and the other end is connected to the filling gun. The liquid hydrogen filling pipeline is provided with a liquid hydrogen booster, a liquid inlet valve, a liquid inlet monitoring system, and a filling pneumatic valve in sequence from the liquid hydrogen storage tank to the filling gun.

[0011] One end of the liquid hydrogen circulation pipeline is connected to the liquid hydrogen storage tank, and the other end is connected to the liquid filling gun inlet. A circulation outlet valve and a first circulation pneumatic valve are sequentially arranged on the liquid hydrogen circulation pipeline from the liquid hydrogen storage tank toward the liquid filling gun inlet.

[0012] One end of the liquid hydrogen circulation branch is connected to the liquid hydrogen filling pipeline and is located between the liquid inlet valve and the liquid inlet monitoring system. The other end is connected to the liquid hydrogen circulation pipeline and is located between the circulation outlet valve and the first circulation pneumatic valve. A second circulation pneumatic valve is provided on the liquid hydrogen circulation branch.

[0013] In some implementations, the liquid hydrogen refueling system also includes a hydrogen return line;

[0014] One end of the hydrogen return pipeline is connected to the liquid hydrogen storage tank, and the other end is connected to the return gas gun. A return gas monitoring system and a return gas pneumatic valve are sequentially installed on the hydrogen return pipeline from the return gas gun toward the liquid hydrogen storage tank.

[0015] In some implementations, the liquid hydrogen refueling system also includes a venting line;

[0016] One end of the venting pipeline is connected to the liquid hydrogen filling pipeline and the hydrogen return pipeline, respectively, and a venting manual valve and a venting pneumatic valve are respectively installed on the connecting pipeline.

[0017] In some implementations, the liquid hydrogen refueling system also includes a displacement pipeline;

[0018] One end of the replacement pipeline is connected in sequence to the liquid hydrogen filling pipeline and the hydrogen return pipeline, respectively located between the filling pneumatic valve and the liquid filling gun, and between the return gas gun and the return gas monitoring system; the other end is connected to the replacement gas source and the hydrogen replacement gas source.

[0019] A return gas replacement valve is installed on the replacement pipeline located between the liquid hydrogen filling pipeline and the hydrogen return gas pipeline.

[0020] In some embodiments, the replacement gas source is also connected to a rewarming purge pipeline, and a rewarming purge manual valve is provided on the rewarming purge pipeline.

[0021] In some embodiments, the liquid hydrogen filling line and the filling gun, and the hydrogen return line and the return gun are respectively connected by a disconnect valve.

[0022] In some embodiments, the liquid inlet monitoring system includes a first temperature transmitter, a liquid hydrogen flow meter, and a first pressure transmitter arranged sequentially from the liquid inlet valve toward the filling pneumatic valve;

[0023] The liquid hydrogen circulation branch is connected between the inlet valve and the first temperature transmitter, and the venting pipeline is connected between the liquid hydrogen flow meter and the first pressure transmitter.

[0024] In some embodiments, the return gas monitoring system includes a second temperature transmitter, a second pressure transmitter, and a hydrogen flow meter arranged sequentially from the return gas gun toward the liquid hydrogen storage tank;

[0025] The displacement pipeline is connected between the second temperature transmitter and the return gas gun, and the venting pipeline is connected between the hydrogen flow meter and the return gas pneumatic valve.

[0026] A liquid hydrogen refueling method, implemented using a liquid hydrogen refueling system as described above, includes the following steps:

[0027] When the liquid hydrogen has not been refilled for a long time, the liquid filling gun is inserted into the liquid filling gun socket, the liquid inlet valve, the circulation outlet valve, and the second circulation pneumatic valve are opened, and the liquid hydrogen booster is controlled to operate at the first preset power until the liquid inlet monitoring system detects that the liquid hydrogen temperature in the liquid hydrogen filling pipeline is lower than the preset temperature. Then, the filling pneumatic valve and the first circulation pneumatic valve are opened, and the second circulation pneumatic valve is closed after a delay to keep the liquid hydrogen filling pipeline in a ready-to-fill state.

[0028] During refueling, the refueling gun is inserted into the vehicle's refueling port, and the liquid hydrogen booster is controlled to operate at the second preset power until refueling is completed. After refueling is completed, the refueling gun is inserted into the refueling gun socket to keep the liquid hydrogen refueling pipeline in a ready-to-refuel state.

[0029] In some embodiments, the liquid hydrogen refueling method further includes the following steps:

[0030] When the refueling state lasts for more than a preset time, the first circulating pneumatic valve is closed and the second circulating pneumatic valve is opened to control the liquid hydrogen booster to operate at the first preset power.

[0031] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art.

[0032] The liquid hydrogen refueling system provided by this invention achieves pre-cooling of all pipelines by setting up liquid hydrogen circulation branch pipes and liquid hydrogen circulation pipelines, preventing a large amount of liquid hydrogen from vaporizing during refueling, thus improving refueling efficiency. Moreover, after refueling is completed, the liquid hydrogen circulation pipelines can be used to maintain the refueling state, saving the replacement process before refueling, simplifying the refueling process, and further improving refueling efficiency. Attached Figure Description

[0033] The accompanying drawings, as part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation of the invention. Obviously, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings:

[0034] Figure 1A and Figure 1B This is a schematic diagram of a liquid hydrogen refueling system provided according to an exemplary embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram of the automatic control process of a liquid hydrogen refueling system provided according to an exemplary embodiment of the present invention;

[0036] Figure 3 and Figure 4 This is a schematic diagram of the precooling process of a liquid hydrogen refueling system provided according to an exemplary embodiment of the present invention.

[0037] In the diagram: 10. Liquid hydrogen refueling system;

[0038] 100. Liquid hydrogen storage tank; 101. Third pressure transmitter; 102. Storage tank safety valve; 103. Storage tank vent valve;

[0039] 200. Liquid hydrogen refueling pipeline; 201. Liquid hydrogen booster; 202. Inlet valve; 203. Inlet monitoring system; 2031. First temperature transmitter; 2032. Liquid hydrogen flow meter; 2033. First pressure transmitter; 204. Refueling pneumatic valve; 205. Liquid hydrogen safety valve; 206. Breakaway valve A; 207. Refueling nozzle;

[0040] 300. Liquid hydrogen circulation pipeline; 301. Circulation outlet valve; 302. First circulation pneumatic valve; 303. Liquid filling gun inlet;

[0041] 400. Liquid hydrogen circulation branch; 401. Second circulation pneumatic valve;

[0042] 500. Hydrogen return pipeline; 501. Return gas monitoring system; 5011. Second temperature transmitter; 5012. Second pressure transmitter; 5013. Hydrogen flow meter; 502. Return gas pneumatic valve; 503. Hydrogen safety valve; 504. Breakaway valve B; 505. Return gas gun;

[0043] 600. Vent line; 601. Vent manual valve; 602. Vent pneumatic valve;

[0044] 700. Replacement pipeline; 701. Replacement gas source; 702. Nitrogen replacement manual valve; 703. Hydrogen replacement gas source; 704. Hydrogen replacement manual valve; 705. Return gas replacement valve;

[0045] 800. Reheat purging pipeline; 801. Reheat purging manual valve;

[0046] 20. Hydrogen system; 21. On-board liquid hydrogen storage tank; 22. On-board liquid filling port; 23. Filling port manual valve; 24. On-board return gas port; 25. Return gas manual valve.

[0047] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0049] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0050] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0051] Figure 1A and Figure 1BThe structure of a liquid hydrogen refueling system 10 provided according to an exemplary embodiment of the present invention is shown.

[0052] like Figure 1A and Figure 1B As shown, the liquid hydrogen refueling system 10 includes a liquid hydrogen storage tank 100, a liquid hydrogen refueling pipeline 200, a hydrogen return pipeline 500, a liquid hydrogen circulation pipeline 300, a liquid hydrogen circulation branch 400, a venting pipeline 600, and a replacement pipeline 700.

[0053] One end of the liquid hydrogen refueling pipeline 200 is connected to the liquid hydrogen storage tank 100, and the other end is connected to the refueling nozzle 207, for supplying hydrogen to the hydrogen-using system 20. The liquid hydrogen refueling pipeline 200, from the liquid hydrogen storage tank 100 towards the refueling nozzle 207, is equipped with a liquid hydrogen booster 201, an inlet valve 202, an inlet monitoring system 203, and a refueling pneumatic valve 204, arranged sequentially. The liquid hydrogen booster 201 is, for example, a liquid hydrogen booster pump.

[0054] One end of the hydrogen return pipeline 500 is connected to the liquid hydrogen storage tank 100, and the other end is connected to the return gas gun 505 via a disconnect valve B504, for recovering hydrogen during the hydrogen supply process to the hydrogen-using system 20. A return gas monitoring system 501 and a return gas pneumatic valve 502 are sequentially installed on the hydrogen return pipeline 500 from the return gas gun 505 toward the liquid hydrogen storage tank 100.

[0055] One end of the liquid hydrogen circulation pipeline 300 is connected to the liquid hydrogen storage tank 100, and the other end is connected to the filling gun inlet 303. It is understood that the filling gun 207 is always inserted into the filling gun inlet 303 when not filling. A circulation outlet valve 301 and a first circulation pneumatic valve 302 are sequentially arranged on the liquid hydrogen circulation pipeline 300 from the liquid hydrogen storage tank 100 towards the filling gun inlet 303. One end of the liquid hydrogen circulation branch 400 is connected to the liquid hydrogen filling pipeline 200, located between the inlet valve 202 and the inlet monitoring system 203, and the other end is connected to the liquid hydrogen circulation pipeline 300, located between the circulation outlet valve 301 and the first circulation pneumatic valve 302. A second circulation pneumatic valve 401 is provided on the liquid hydrogen circulation branch 400.

[0056] One end of the venting line 600 is connected to the liquid hydrogen filling line 200 and the hydrogen return line 500, respectively, and a venting manual valve 601 and a venting pneumatic valve 602 are respectively installed on the connecting lines. To provide overpressure protection for the liquid hydrogen filling line 200 and the hydrogen return line 500 during the purging and filling processes, a liquid hydrogen safety valve 205 and a hydrogen safety valve 503 are respectively installed between the liquid hydrogen filling line 200 and the hydrogen return line 500 and the venting line 600. It should be noted that the other end of the venting line 600 is connected to a main venting pipe or a hydrogen recovery tank for unified treatment.

[0057] One end of the replacement pipeline 700 is sequentially connected to the liquid hydrogen filling pipeline 200 and the hydrogen return pipeline 500, located between the filling pneumatic valve 204 and the liquid filling gun 207, and between the return gas gun 505 and the return gas monitoring system 501, respectively. The other end is connected to the replacement gas source 701 and the hydrogen replacement gas source 703, respectively. A return gas replacement valve 705 is installed on the replacement pipeline 700 located between the liquid hydrogen filling pipeline 200 and the hydrogen return pipeline 500. The replacement gas source 701 is, for example, a nitrogen source. A nitrogen replacement manual valve 702 is installed on the connecting pipeline between the replacement pipeline 700 and the nitrogen source, and a hydrogen replacement manual valve 704 is installed on the connecting pipeline between the replacement pipeline 700 and the hydrogen replacement gas source 703.

[0058] The replacement gas source 701 is also connected to a reheat purging pipeline 800, which is used to purge the filling port of the hydrogen system 20 before filling. The reheat purging pipeline 800 is equipped with a reheat purging manual valve 801.

[0059] The liquid inlet monitoring system 203 includes a first temperature transmitter 2031, a liquid hydrogen flow meter 2032, and a first pressure transmitter 2033 sequentially arranged from the liquid inlet valve 202 toward the filling pneumatic valve 204; wherein, the liquid hydrogen circulation branch 400 is connected between the liquid inlet valve 202 and the first temperature transmitter 2031, and the venting pipeline 600 is connected between the liquid hydrogen flow meter 2032 and the first pressure transmitter 2033. The return gas monitoring system 501 includes a second temperature transmitter 5011, a second pressure transmitter 5012, and a hydrogen flow meter 5013 sequentially arranged from the return gas gun 505 toward the liquid hydrogen storage tank 100; wherein, the displacement pipeline 700 is connected between the second temperature transmitter 5011 and the return gas gun 505, and the venting pipeline 600 is connected between the hydrogen flow meter 5013 and the return gas pneumatic valve 502.

[0060] The following describes the automatic control process of the liquid hydrogen refueling system 10, using hydrogen system 20 as an example of an on-board hydrogen storage system that supplies hydrogen to a hydrogen fuel cell. The on-board hydrogen storage system includes an on-board liquid hydrogen storage tank 21 and an on-board liquid filling pipeline and an on-board return gas pipeline connected to the on-board liquid hydrogen storage tank 21. The on-board liquid filling pipeline is connected to the on-board liquid filling port 22 and is equipped with a filling port manual valve 23; the on-board return gas pipeline is connected to the on-board return gas port 24 and is equipped with a return gas manual valve 25.

[0061] It should be noted that the liquid hydrogen refueling system 10 also includes a control system, which is a PLC automatic control system. The control panel of the control system has functions such as replacement mode, small circulation mode, large circulation mode, refueling preparation mode, and refueling mode. Different control modes have preset control commands for different valves.

[0062] The following is a reference. Figure 1A The initial permutation process is described in detail.

[0063] When the liquid hydrogen refueling system 10 is installed or restarted after a long period of inactivity, close the inlet valve 202, circulation outlet valve 301, venting hand valve 601, and venting pneumatic valve 602. Click the replacement mode on the control panel to automatically open the refueling pneumatic valve 204, the first circulation pneumatic valve 302, the second circulation pneumatic valve 401, and the return gas replacement valve 705, and close the return gas pneumatic valve 502.

[0064] First, open the nitrogen purging hand valve 702. Nitrogen from the nitrogen source passes through the purging pipeline 700, with some nitrogen entering the liquid hydrogen filling pipeline 200. After passing through the filling pneumatic valve 204 and the liquid inlet monitoring system 203, it enters the liquid hydrogen circulation branch 400. After passing through the second circulation pneumatic valve 401, it enters the liquid hydrogen circulation pipeline 300. After passing through the first circulation pneumatic valve 302, it merges with the nitrogen that has passed through the disconnect valve A206, the filling gun 207, and the filling gun inlet 303, forming a loop. The remaining nitrogen enters the hydrogen return pipeline 500 after passing through the return gas purging valve 705. When the nitrogen pressure in the liquid hydrogen filling pipeline 200 and the hydrogen return pipeline 500 exceeds the preset purging pressure, close the nitrogen purging hand valve 702 and open the venting hand valve 601 to release the pressure. Multiple nitrogen purgings are performed using the opening and closing of the nitrogen purging hand valve 702 and the venting hand valve 601.

[0065] Then close the nitrogen purging valve 702 and open the hydrogen purging valve 704. Following the above process, use the switches of the hydrogen purging valve 704 and the venting valve 601 to perform multiple hydrogen purgings. Click "End Purging," and the filling pneumatic valve 204, the first cycle pneumatic valve 302, the second cycle pneumatic valve 401, and the return gas purging valve 705 will automatically close.

[0066] Furthermore, the aforementioned hydrogen replacement manual valve 704 and nitrogen replacement manual valve 702 can be replaced with pneumatic valves, which, in conjunction with the venting pneumatic valve 602, achieve fully automatic control of the replacement process, further improving the automation level of the liquid hydrogen refueling system 10 of this invention. The aforementioned liquid inlet valve 202 and circulation outlet valve 301 can also be configured as manual valves or pneumatic valves according to actual needs; this invention does not impose any limitations here.

[0067] It should be noted that the connecting pipelines between the liquid hydrogen storage tank 100 and the inlet valve 202, the return gas pneumatic valve 502, and the circulation outlet valve 301 can be replaced simultaneously during the replacement of the liquid hydrogen storage tank 100. After the liquid hydrogen storage tank 100 has been replaced, liquid hydrogen is then introduced. This completes the initial replacement process of the liquid hydrogen refueling system 10.

[0068] It should be noted that the liquid hydrogen storage tank 100 is equipped with a third pressure transmitter 101 to monitor the gas pressure inside the liquid hydrogen storage tank 100. The liquid hydrogen storage tank 100 is equipped with a manual or pneumatic tank vent valve 103. When the gas pressure inside the liquid hydrogen storage tank 100 measured by the third pressure transmitter 101 exceeds the set value, the tank vent valve 103 needs to be opened to vent the cryogenic hydrogen or store it in a recovery tank. Furthermore, to further improve the safety of the liquid hydrogen storage tank 100, it is also equipped with a tank safety valve 102. The tank vent valve 103 and the tank safety valve 102 deliver hydrogen to the vent manifold or the hydrogen recovery tank.

[0069] The following is a reference. Figure 1B , Figures 2-4 The filling process is described in detail.

[0070] Before the first filling, first open the inlet valve 202 and the circulation outlet valve 301. Then, on the control panel, click the small circulation mode. Figure 3 As shown, the second circulation pneumatic valve 401 is automatically opened, and after a 1-minute delay, the liquid hydrogen booster 201 is opened. The liquid hydrogen booster 201 is controlled to operate at the first preset power, pressurizing the liquid hydrogen in the liquid hydrogen filling pipeline 200 and circulating it to the liquid hydrogen storage tank 100. During this process, the liquid hydrogen filling pipeline 200 before the filling pneumatic valve 204, the liquid hydrogen circulation branch 400, and the liquid hydrogen circulation pipeline 300 before the first circulation pneumatic valve 302 are pre-cooled. The temperature of the first temperature transmitter 2031 is monitored in real time. When the temperature T1 of the first temperature transmitter 2031 is lower than the preset temperature, for example, the liquid hydrogen temperature is 20K, it indicates that the pre-cooling of the relevant pipelines is complete. Click the large circulation mode on the control panel, as shown. Figure 4As shown, the pneumatic valve 204 for filling and the first circulation pneumatic valve 302 are automatically opened. After a delay of 30 seconds, the second circulation pneumatic valve 401 is closed. Liquid hydrogen flows through the break-off valve A206, the filling gun 207, the first circulation pneumatic valve 302, and the circulation outlet valve 301 before entering the liquid hydrogen storage tank 100. This completes the pre-cooling of all pipelines, and the tank awaits the arrival of liquid hydrogen vehicles for filling.

[0071] When a liquid hydrogen vehicle arrives to refuel, before refueling, first insert the communication signal line of the onboard storage tank into the receiving port of the liquid hydrogen refueling system 10. Open the rewarming purge hand valve 801 to purge impurities from the onboard liquid filling port 22 and the onboard return air port 24.

[0072] Insert the return gas gun 505 into the vehicle return gas port 24 of the vehicle-mounted liquid hydrogen storage tank 21, click "Prepare for Refilling", and monitor the gas pressure P2 in the hydrogen return gas pipeline 500 and the gas pressure P3 in the liquid hydrogen storage tank 100 through the second pressure transmitter 5012 and the third pressure transmitter 101, respectively. If the gas pressure P2 in the hydrogen return gas pipeline 500 exceeds the gas pressure P3 in the liquid hydrogen storage tank 100, open the vent valve 602 to release the pressure until the gas pressure P2 in the hydrogen return gas pipeline 500 is lower than the gas pressure P3 in the liquid hydrogen storage tank 100, and then close the vent valve 602.

[0073] Turn off the liquid hydrogen booster 201, and close the first cycle pneumatic valve 302 and the filling pneumatic valve 204. Open the return gas pneumatic valve 502 to connect the on-board liquid hydrogen storage tank 21 with the liquid hydrogen storage tank 100, so that the pressures are the same.

[0074] Once the filling system screen displays "ready to finish", remove the filling gun 207 from the filling gun port 303 and insert it into the vehicle filling port 22 of the vehicle liquid hydrogen storage tank 21, and open the filling port manual valve 23 on the vehicle liquid hydrogen storage tank 21.

[0075] Clicking "Start Refilling" on the control panel automatically opens the pneumatic valve 204 and the liquid hydrogen booster 201. The liquid hydrogen booster 201 begins pressurizing at the second preset power, delivering liquid hydrogen through the liquid hydrogen refilling system 10 into the on-board liquid hydrogen storage tank 21. Simultaneously, the cryogenic hydrogen above the on-board liquid hydrogen storage tank 21 returns to the liquid hydrogen storage tank 100 via the return valve 25, return nozzle 505, and hydrogen return pipeline 500. At the same time, the liquid hydrogen flow meter 2032 and hydrogen flow meter 5013 begin metering, transmitting the data to the controller for differential calculation and displaying the refill amount on the hydrogen dispenser screen. The refilling progress in the on-board liquid hydrogen storage tank 21 is transmitted to the control system via signal lines and displayed on the control panel.

[0076] When the capacity of the on-board liquid hydrogen storage tank 21 exceeds 90%, the liquid hydrogen booster 201 automatically stops working, the filling pneumatic valve 204 automatically closes, and the filling is completed by clicking on the control panel. The liquid hydrogen flow meter 2032 and the hydrogen flow meter 5013 stop measuring and the final hydrogen filling amount is displayed on the screen.

[0077] Close the manual valve 23 at the filling port and the manual valve 25 at the return gas port on the vehicle-mounted liquid hydrogen storage tank 21. Close the connecting valves on the filling gun 207 and the return gas gun 505. Open the rewarming purge manual valve 801 to blow away the frost at the connection and rewarm it. If the filling gun 207 is equipped with a nitrogen rewarming valve, you can open it to defrost and rewarm, and then close the nitrogen rewarming valve. Then close the rewarming purge manual valve 801. Pull out the return gas gun 505 and the filling gun 207 in sequence. Insert the filling gun 207 back into the filling gun socket 303. Click "Start Large Circulation Mode" on the control panel. The liquid hydrogen booster 201, the first circulation pneumatic valve 302, and the filling pneumatic valve 204 will be automatically opened to start the large circulation of liquid hydrogen, so that the liquid hydrogen filling pipeline 200 continues to be in a ready-to-fill state, preparing for the arrival of the next vehicle.

[0078] In the above scheme, the liquid hydrogen circulation branch 400 and liquid hydrogen circulation pipeline 300 are set up to pre-cool all pipelines, preventing the liquid hydrogen from being vaporized in large quantities during refueling, thus improving refueling efficiency. Moreover, after refueling is completed, the liquid hydrogen circulation pipeline 300 can be used to maintain the state ready for refueling, saving the replacement process before refueling, simplifying the refueling process, and further improving refueling efficiency.

[0079] If there is no vehicle refueling for an extended period (≥1 hour) on the same day, or when leaving get off work in the evening, the large circulation mode will be automatically shut off, the first circulation pneumatic valve 302 and the refueling pneumatic valve 204 will be closed, the second circulation pneumatic valve 401 will be opened, and the small circulation mode will be automatically switched to. At the same time, the return gas replacement valve 705 will be opened to prevent the liquid hydrogen in the pipeline from evaporating and causing overpressure.

[0080] To save energy, the liquid hydrogen booster 201 can be set with an outlet pressure and operating power that match the actual filling and circulation conditions. In the small circulation mode, the power consumption of the liquid hydrogen booster 201 should be minimized. Before filling again, it needs to be switched to large circulation mode and run for 3 minutes before it can be refilled.

[0081] If the liquid hydrogen refueling system 10 is not used for more than a week, the inlet valve 202, circulation outlet valve 301, and return gas pneumatic valve 502 should be closed. The refueling pneumatic valve 204, first circulation pneumatic valve 302, second circulation pneumatic valve 401, and return gas replacement valve 705 should be opened. The hydrogen replacement manual valve 704 and nitrogen replacement manual valve 702 should be used in conjunction with the venting manual valve 601 to complete the hydrogen and nitrogen replacement of all pipelines in the liquid hydrogen refueling system 10 and ensure a slight positive pressure.

[0082] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A liquid hydrogen refueling method, implemented using a liquid hydrogen refueling system, characterized in that, The liquid hydrogen refueling system includes a liquid hydrogen storage tank, a liquid hydrogen refueling pipeline, a liquid hydrogen circulation pipeline, a liquid hydrogen circulation branch, and a hydrogen return pipeline; One end of the liquid hydrogen filling pipeline is connected to the liquid hydrogen storage tank, and the other end is connected to the filling gun. The liquid hydrogen filling pipeline is provided with a liquid hydrogen booster, a liquid inlet valve, a liquid inlet monitoring system, and a filling pneumatic valve in sequence from the liquid hydrogen storage tank to the filling gun. One end of the liquid hydrogen circulation pipeline is connected to the liquid hydrogen storage tank, and the other end is connected to the liquid filling gun inlet. A circulation outlet valve and a first circulation pneumatic valve are sequentially arranged on the liquid hydrogen circulation pipeline from the liquid hydrogen storage tank toward the liquid filling gun inlet. One end of the liquid hydrogen circulation branch is connected to the liquid hydrogen filling pipeline and is located between the liquid inlet valve and the liquid inlet monitoring system. The other end is connected to the liquid hydrogen circulation pipeline and is located between the circulation outlet valve and the first circulation pneumatic valve. A second circulation pneumatic valve is provided on the liquid hydrogen circulation branch. One end of the hydrogen return pipeline is connected to the liquid hydrogen storage tank, and the other end is connected to the return gas gun. A return gas monitoring system and a return gas pneumatic valve are sequentially installed on the hydrogen return pipeline from the return gas gun toward the liquid hydrogen storage tank. The liquid hydrogen refueling method includes the following steps: When the liquid hydrogen has not been refilled for a long time, the liquid filling gun is inserted into the liquid filling gun socket, the liquid inlet valve, the circulation outlet valve, and the second circulation pneumatic valve are opened, and the liquid hydrogen booster is controlled to operate at the first preset power until the liquid inlet monitoring system detects that the liquid hydrogen temperature in the liquid hydrogen filling pipeline is lower than the preset temperature. Then, the filling pneumatic valve and the first circulation pneumatic valve are opened, and the second circulation pneumatic valve is closed after a delay to keep the liquid hydrogen filling pipeline in a ready-to-fill state. During refueling, the refueling gun is inserted into the vehicle's refueling port, and the liquid hydrogen booster is controlled to operate at the second preset power until refueling is completed. After refueling is completed, the refueling gun is inserted into the refueling gun socket to keep the liquid hydrogen refueling pipeline in a ready-to-refuel state. When the refueling state lasts for more than a preset time, the first circulating pneumatic valve is closed and the second circulating pneumatic valve is opened to control the liquid hydrogen booster to operate at the first preset power.

2. The liquid hydrogen refueling method according to claim 1, characterized in that, It also includes venting pipelines; One end of the venting pipeline is connected to the liquid hydrogen filling pipeline and the hydrogen return pipeline, respectively, and a venting manual valve and a venting pneumatic valve are respectively installed on the connecting pipeline.

3. The liquid hydrogen refueling method according to claim 2, characterized in that, This also includes replacement tubing; One end of the replacement pipeline is connected in sequence to the liquid hydrogen filling pipeline and the hydrogen return pipeline, respectively located between the filling pneumatic valve and the liquid filling gun, and between the return gas gun and the return gas monitoring system; the other end is connected to the replacement gas source and the hydrogen replacement gas source. A return gas replacement valve is installed on the replacement pipeline located between the liquid hydrogen filling pipeline and the hydrogen return gas pipeline.

4. The liquid hydrogen refueling method according to claim 3, characterized in that, The replacement gas source is also connected to a reheating purge pipeline, and a reheating purge manual valve is installed on the reheating purge pipeline.

5. The liquid hydrogen refueling method according to any one of claims 1 to 4, characterized in that, The liquid hydrogen filling line is connected to the filling gun, and the hydrogen return line is connected to the return gun via disconnect valves.

6. The liquid hydrogen refueling method according to any one of claims 2 to 4, characterized in that, The liquid inlet monitoring system includes a first temperature transmitter, a liquid hydrogen flow meter, and a first pressure transmitter arranged sequentially from the liquid inlet valve toward the filling pneumatic valve. The liquid hydrogen circulation branch is connected between the inlet valve and the first temperature transmitter, and the venting pipeline is connected between the liquid hydrogen flow meter and the first pressure transmitter.

7. The liquid hydrogen refueling method according to claim 3 or 4, characterized in that, The return gas monitoring system includes a second temperature transmitter, a second pressure transmitter, and a hydrogen flow meter arranged sequentially from the return gas gun toward the liquid hydrogen storage tank. The displacement pipeline is connected between the second temperature transmitter and the return gas gun, and the venting pipeline is connected between the hydrogen flow meter and the return gas pneumatic valve.

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