A rapid precooling system and method for a liquid hydrogen refueling station

Abstract

This invention discloses a rapid precooling system and method for a liquid hydrogen refueling station, belonging to the field of liquid hydrogen technology. The precooling system includes a liquid hydrogen refueling pipeline, a liquid hydrogen supply tank, a valve subsystem, a liquid hydrogen refueling tank, a circulation pipeline, a condenser, a gas-liquid separator, a liquid carbon dioxide tank, a storage cylinder, a helium pipeline, a high-pressure helium cylinder, a fuel cell, a cryogenic hydrogen pipeline, and a liquid hydrogen storage tank group. This system utilizes liquid carbon dioxide and cryogenic helium to achieve deep coupling between system displacement and precooling operations. After displacement, the system temperature has dropped below the temperature of liquid carbon dioxide, significantly reducing precooling time. It also utilizes cryogenic hydrogen stored in the liquid hydrogen storage tank group to liquefy carbon dioxide, achieving carbon dioxide medium circulation. Simultaneously, the hydrogen released after cooling and the hydrogen generated during precooling are transported to the fuel cell for power generation, improving hydrogen utilization efficiency.

Description

Technical Field

[0001] This invention belongs to the field of liquid hydrogen technology, specifically relating to a rapid precooling system and method for a liquid hydrogen refueling station. Background Technology

[0002] Hydrogen refueling stations, as key infrastructure for the application of hydrogen energy in the transportation sector, serve as a link between upstream hydrogen supply and downstream fuel cell vehicle users. Statistics show that as of the end of June 2022, China had built over 270 hydrogen refueling stations. These stations can be broadly categorized into gaseous hydrogen refueling stations and liquid hydrogen refueling stations based on the different phases of hydrogen stored within them. In conventional gaseous hydrogen refueling stations, hydrogen is first processed through a pressure regulating and drying system to ensure it is converted into a stable, dry gas. The processed hydrogen is then transported to a hydrogen compressor, subsequently stored in a high-pressure hydrogen storage tank, and finally dispensed via a hydrogen refueling machine. This process is relatively mature.

[0003] In recent years, with the emergence of new vehicles such as liquid hydrogen heavy-duty trucks, hydrogen refueling stations that directly dispense liquid hydrogen have received increasing attention. Compared with traditional high-pressure gaseous hydrogen storage, liquid hydrogen storage tanks have a smaller volume for the same hydrogen storage capacity, meaning that liquid hydrogen refueling stations require less land and require less investment in construction. Furthermore, liquid hydrogen refueling stations offer advantages such as high storage and transportation efficiency, low transportation costs, low unit investment, low energy consumption within the station, and strong compatibility, making them an ideal choice for large-scale hydrogen refueling stations. However, the liquid hydrogen refueling process is much more complex than conventional gaseous hydrogen refueling. In addition to the necessary purging and replacement steps, deep precooling of the entire system is required to ensure the stability of the liquid hydrogen during refueling. These additional steps prolong the refueling time, thus affecting the overall efficiency of liquid hydrogen refueling. Therefore, there is a need to develop a rapid precooling system for liquid hydrogen refueling stations. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a rapid precooling system and method for liquid hydrogen refueling stations. This system utilizes carbon dioxide as an intermediate cooling medium to achieve a unified coupling of displacement and precooling, significantly reducing the overall precooling time of the system. Simultaneously, it utilizes high-pressure helium for deep displacement and incorporates a dew point cooler to comprehensively enhance the displacement and precooling effects.

[0005] The specific technical solution adopted in this invention is as follows:

[0006] In a first aspect, the present invention provides a rapid precooling system for a liquid hydrogen refueling station, including a liquid hydrogen refueling pipeline, a liquid hydrogen supply tank, a valve subsystem, a liquid hydrogen refueling tank, a circulation pipeline, a condenser, a gas-liquid separator, a liquid carbon dioxide tank, a gas storage cylinder, a helium pipeline, a high-pressure helium cylinder, a fuel cell, a cryogenic hydrogen pipeline, and a liquid hydrogen storage tank group.

[0007] The liquid hydrogen refueling pipeline is sequentially connected to a liquid hydrogen supply tank, a first liquid hydrogen shut-off valve, a pipe and valve subsystem, a second liquid hydrogen shut-off valve, and a liquid hydrogen refueling tank, transferring the liquid hydrogen medium from the liquid hydrogen supply tank to the liquid hydrogen refueling tank; the liquid hydrogen refueling tank is equipped with an air vent valve at the top;

[0008] The circulation pipeline is sequentially connected to the liquid hydrogen filling tank, the fourth shut-off valve, the first channel of the condenser, the gas-liquid separator, the liquid carbon dioxide tank, the circulation pump, the second shut-off valve, and the third shut-off valve to the liquid hydrogen filling pipeline, so as to realize the circulation liquefaction of carbon dioxide medium.

[0009] The outlet of the gas-liquid separator is equipped with a secondary circulation pipeline; the rear end of the secondary circulation pipeline is divided into two branches. One branch is connected to the circulation pipeline through the fifth shut-off valve to realize the secondary circulation of unliquefied carbon dioxide gas; the other branch is connected to the gas storage cylinder through the sixth shut-off valve to realize the recovery and storage of helium.

[0010] The high-pressure helium cylinder is immersed in a liquid carbon dioxide tank to lower its temperature; the front end of the helium pipeline is connected to the high-pressure helium cylinder through a seventh shut-off valve; the rear end of the helium pipeline splits into two branches. One branch passes through the dry channel of the dew point cooler and then enters the circulation pipeline to further cool the helium in the pipeline for deep displacement; the other branch passes through the wet channel of the dew point cooler and the eighth shut-off valve and then enters the circulation pipeline to separate the helium and carbon dioxide.

[0011] The circulation pipeline and the helium pipeline are connected by a branch equipped with a first shut-off valve, allowing liquid carbon dioxide to enter the helium pipeline through the circulation pipeline; the fuel cell is connected to the circulation pipeline through a branch equipped with a ninth shut-off valve, and receives deeply cooled hydrogen to generate electricity.

[0012] The cryogenic hydrogen pipeline is sequentially connected to the liquid hydrogen storage tank group, the tenth shut-off valve, the second channel of the condenser, and then to the fuel cell, so that the fuel cell receives carbon dioxide liquefied from the cryogenic hydrogen generated by the liquid hydrogen storage tank group to generate electricity.

[0013] Preferably, the valve subsystem includes a liquid hydrogen valve and a liquid hydrogen metering element.

[0014] Furthermore, the liquid hydrogen valve may be a ball valve, a gate valve, a regulating valve, or a safety valve.

[0015] Furthermore, the liquid hydrogen metering element is a mass flow meter, level gauge, velocity meter, temperature sensor, or pressure sensor.

[0016] Preferably, the valve subsystem further includes a liquid hydrogen functional component disposed between the liquid hydrogen valve and the liquid hydrogen metering element; the liquid hydrogen functional component is a pressure regulating component, a temperature regulating component, or a pump component.

[0017] Preferably, the liquid hydrogen refueling pipeline, circulation pipeline, liquid hydrogen refueling tank, and liquid carbon dioxide tank are all equipped with heat insulation materials to prevent heat leakage.

[0018] Preferably, the liquid hydrogen supply tank delivers liquid hydrogen via a self-pressurization method.

[0019] Preferably, the condenser is a low-temperature plate-fin heat exchanger or a microchannel heat exchanger.

[0020] Preferably, the gas-liquid separator adopts a centrifugal gas-liquid separation structure to improve separation efficiency.

[0021] In a second aspect, the present invention provides a method for using the rapid precooling system of the liquid hydrogen refueling station described in the first aspect, wherein in the initial stage all valves are closed and all devices are in a stopped state;

[0022] S1: Startup Phase

[0023] When the tenth shut-off valve is opened, the cryogenic hydrogen from the liquid hydrogen storage tank group enters the cryogenic hydrogen pipeline, passes through the tenth shut-off valve into the second channel of the condenser to release its cooling capacity, and then enters the fuel cell to generate electricity.

[0024] S2: Primary displacement and precooling stage:

[0025] Open the liquid hydrogen valve, second liquid hydrogen shut-off valve, fourth shut-off valve, second shut-off valve, third shut-off valve, and fifth shut-off valve in the pipe and valve subsystem; start the gas-liquid separator and circulation pump. Driven by the circulation pump, the liquid carbon dioxide in the liquid carbon dioxide tank enters the liquid hydrogen filling pipeline through the second shut-off valve and the third shut-off valve in sequence, replacing and cooling the pipe and valve subsystem and the liquid hydrogen filling tank, so that the liquid carbon dioxide is converted into gaseous carbon dioxide.

[0026] Gaseous carbon dioxide enters the first channel of the condenser through the fourth shut-off valve to absorb cold energy and liquefy, and then enters the gas-liquid separator. Under the action of the gas-liquid separator, the unliquefied carbon dioxide gas returns to the circulation pipeline through the fifth shut-off valve to absorb cold energy, while the liquid carbon dioxide enters the liquid carbon dioxide tank. This process is repeated until the temperature of the pipe and valve subsystem and the liquid hydrogen filling tank are both the temperature of liquid carbon dioxide. At this time, the initial replacement and pre-cooling stage is completed, and the second shut-off valve and the fifth shut-off valve are closed.

[0027] S3: Deep Displacement and Pre-cooling Stage:

[0028] Open the first, sixth, seventh, and eighth shut-off valves; start the circulation pump. Liquid carbon dioxide in the liquid carbon dioxide tank enters the wet channel of the dew point cooler through the first shut-off valve. After passing through the seventh shut-off valve, part of the cryogenic helium from the high-pressure helium cylinder enters the wet channel of the dew point cooler. Liquid carbon dioxide in the dew point cooler diffuses and evaporates into the cryogenic helium, generating cooling energy. The resulting mixture enters the circulation pipeline through the eighth shut-off valve. Another part of the cryogenic helium enters the dry channel of the dew point cooler, absorbs the cooling energy in the wet channel, and is further cooled. It then undergoes deep replacement and cooling of the pipe valve subsystem and liquid hydrogen filling tank through the third shut-off valve. Subsequently, it merges with the mixture from the wet channel through the fourth shut-off valve and enters the first channel of the condenser to absorb cooling energy. The carbon dioxide in the mixture liquefies again. Under the action of the gas-liquid separator, the liquid carbon dioxide in the mixture enters the liquid carbon dioxide tank, while the helium enters the storage cylinder through the sixth shut-off valve.

[0029] Continue the above process until the purity of the gas after replacement meets the requirements. Then stop the gas-liquid separator and the circulation pump, and close the first, third, fourth, sixth, seventh, and eighth shut-off valves. The replacement is now complete.

[0030] S4: Liquid hydrogen precooling stage:

[0031] Open the first liquid hydrogen shut-off valve and the ninth shut-off valve; the liquid hydrogen supply tank enters a low-pressure state through self-pressurization. Under the action of pressure difference, liquid hydrogen enters the pipe and valve subsystem and liquid hydrogen filling tank through the first liquid hydrogen shut-off valve to continue pre-cooling. The generated hydrogen gas enters the fuel cell to power the fuel cell through the ninth shut-off valve. Continue the above process until the temperature of the pipe and valve subsystem and the liquid hydrogen filling tank are both liquid hydrogen temperature, and the liquid hydrogen pre-cooling is completed.

[0032] S5: Betting Phase

[0033] The liquid hydrogen supply tank enters a high-pressure state through self-pressurization to begin the filling process; a large amount of liquid hydrogen enters the pipe valve subsystem and the liquid hydrogen filling tank through the first liquid hydrogen shut-off valve. The hydrogen generated during the filling process continues to enter the fuel cell to supply power through the ninth shut-off valve. When the liquid hydrogen inside the liquid hydrogen filling tank reaches the set level, the filling is completed. The vent valve is opened, and the first liquid hydrogen shut-off valve, the liquid hydrogen valve in the pipe valve subsystem, the second liquid hydrogen shut-off valve, the ninth shut-off valve, and the tenth shut-off valve are closed, and the fuel cell stops operating.

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] (1) The rapid precooling system provided by the present invention utilizes liquid carbon dioxide and cryogenic helium to achieve deep coupling between system displacement operation and precooling operation; after displacement is completed, the system temperature has been reduced to below the temperature of liquid carbon dioxide, which significantly reduces the precooling time;

[0036] (2) The rapid precooling system provided by the present invention immerses the high-pressure helium cylinder in a liquid carbon dioxide tank for cooling, which effectively reduces the temperature of the helium; at the same time, a dew point cooler is provided to cool the helium for a second time, which improves the precooling effect during helium replacement; and a helium recovery system is set up to avoid the waste of helium resources.

[0037] (3) The rapid precooling system provided by the present invention also utilizes the low-temperature hydrogen stored in the liquid hydrogen storage tank group to liquefy carbon dioxide, realize the circulation of carbon dioxide medium, and at the same time transport the hydrogen after releasing the cold energy and the hydrogen generated by precooling to the fuel cell for power generation, thereby improving the utilization efficiency of hydrogen. Attached Figure Description

[0038] Figure 1 A schematic diagram of the rapid precooling system for a liquid hydrogen refueling station provided by the present invention;

[0039] In the diagram: 1. Liquid hydrogen refueling pipeline; 2. Liquid hydrogen supply tank; 3. First liquid hydrogen shut-off valve; 4. Pipe and valve subsystem; 5. Liquid hydrogen valve; 6. Liquid hydrogen functional component; 7. Liquid hydrogen metering element; 8. Second liquid hydrogen shut-off valve; 9. Liquid hydrogen refueling tank; 10. Vent valve; 11. Circulation pipeline; 12. Condenser; 13. Gas-liquid separator; 14. Liquid carbon dioxide tank; 15. Circulation pump; 16. First shut-off valve; 17. Second shut-off valve; 18. Third shut-off valve; 19. Fourth shut-off valve; 20. Secondary circulation pipeline; 21. Fifth shut-off valve; 22. Sixth shut-off valve; 23. Gas storage cylinder; 24. Helium pipeline; 25. High-pressure helium cylinder; 26. Seventh shut-off valve; 27. Dry channel; 28. Wet channel; 29. ​​Eighth shut-off valve; 30. Ninth shut-off valve; 31. Fuel cell; 32. Cryogenic hydrogen pipeline; 33. Liquid hydrogen storage tank group; 34. Tenth shut-off valve. Detailed Implementation

[0040] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. Technical features in the various embodiments of the present invention can be combined accordingly without mutual conflict.

[0041] In the description of this invention, it should be understood that when an element is considered to be "connected" to another element, it can be a direct connection to the other element or an indirect connection, i.e., there is an intermediate element. Conversely, when an element is said to be "directly" connected to another element, there is no intermediate element.

[0042] In the description of this invention, it should be understood that the terms "first" and "second" are used only for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" and "second" may explicitly or implicitly include at least one of those features.

[0043] In the description of this invention, it should be understood that the terms "high pressure" and "low pressure" refer to high or low pressure relative to the pressure of the same medium in the same passage, and should not be construed as indicating or implying relative importance or implicitly specifying the pressure value of the indicated technical feature. Similarly, in the description of this invention, it should be understood that the terms "low temperature" and "high temperature" (e.g., "low-temperature hydrogen") refer to high or low temperature relative to the temperature of the same medium in the same passage, and should not be construed as indicating or implying relative importance or implicitly specifying the temperature value of the indicated technical feature.

[0044] like Figure 1 As shown, in a preferred embodiment of the present invention, a rapid precooling system for a liquid hydrogen refueling station is provided, including a liquid hydrogen refueling pipeline 1, a liquid hydrogen supply tank 2, a valve subsystem 4, a liquid hydrogen refueling tank 9, a circulation pipeline 11, a condenser 12, a gas-liquid separator 13, a liquid carbon dioxide tank 14, a gas storage cylinder 23, a helium pipeline 24, a high-pressure helium cylinder 25, a fuel cell 31, a cryogenic hydrogen pipeline 32, and a liquid hydrogen storage tank group 33.

[0045] In the system of this invention, the liquid hydrogen refueling pipeline 1 is sequentially connected to the liquid hydrogen supply tank 2, the first liquid hydrogen shut-off valve 3, the pipe and valve subsystem 4, the second liquid hydrogen shut-off valve 8, and the liquid hydrogen refueling tank 9, transferring the liquid hydrogen medium from the liquid hydrogen supply tank 2 to the liquid hydrogen refueling tank 9. The top of the liquid hydrogen refueling tank 9 is equipped with a vent valve 10, used to release excess pressure during the refueling process, or to discharge any impurities or gases that may be present in the tank, ensuring the purity of the liquid hydrogen.

[0046] It should be noted that the pipe and valve subsystem package used in this embodiment, which is sequentially connected to the liquid hydrogen valve 5, the liquid hydrogen functional component 6, and the liquid hydrogen metering element 7, represents the collection of various pipe and valve components at the front end of the liquid hydrogen refueling system.

[0047] It should be noted that liquid hydrogen valves are a common type of valve in liquid hydrogen refueling systems, used to control and manage the flow of liquid hydrogen. In liquid hydrogen refueling systems, the main function of these valves is to ensure the safe and efficient transfer of liquid hydrogen from one storage container to another or another system. Because liquid hydrogen remains liquid only at extremely low temperatures, these valves must be able to withstand extreme cryogenic environments. This invention does not specifically limit the type and material of the liquid hydrogen valves; those skilled in the art can select valves suitable for the liquid hydrogen refueling system based on specific operating conditions, such as ball valves, gate valves, regulating valves, or safety valves.

[0048] It should be noted that the liquid hydrogen functional component 6 can be a pressure regulating component, a temperature regulating component, or a pump component. This invention does not limit the specific form of the liquid hydrogen functional component; those skilled in the art can select appropriate functional components based on the liquid hydrogen conditions required by the downstream ejector subsystem. Specifically, pressure buffer tanks, heat exchangers, or liquid hydrogen pumps can be selected. The selection and configuration of these components depend on the specific system design and operational requirements. When designing a liquid hydrogen refueling system, the performance indicators of these components and their interoperability must be comprehensively considered to ensure the safe, stable, and efficient operation of the system.

[0049] It should be noted that the liquid hydrogen metering unit is the device responsible for accurately measuring the liquid hydrogen flow rate in the liquid hydrogen refueling system, ensuring the accuracy and efficiency of the liquid hydrogen refueling process. This invention does not specifically limit the type and material of the liquid hydrogen metering unit; those skilled in the art can select a suitable metering unit based on specific operating conditions, such as a mass flow meter, level gauge, velocity meter, temperature sensor, or pressure sensor.

[0050] In the system of this invention, the circulation pipeline 11 is sequentially connected to the liquid hydrogen refueling tank 9, the fourth shut-off valve 19, the first channel of the condenser 12, the gas-liquid separator 13, the liquid carbon dioxide tank 14, the circulation pump 15, the second shut-off valve 17, and the third shut-off valve 18 to the liquid hydrogen refueling pipeline 1, thereby realizing the cyclic liquefaction of carbon dioxide. Furthermore, a secondary circulation pipeline 20 is provided at the outlet of the gas-liquid separator 13, and the rear end of the secondary circulation pipeline 20 splits into two branches. One branch is connected to the circulation pipeline 11 via the fifth shut-off valve 21, enabling the unliquefied carbon dioxide gas separated by the gas-liquid separator 13 to be transported to the circulation pipeline 11 for secondary circulation. The other branch at the rear end of the secondary circulation pipeline 20 is connected to the gas storage cylinder 23 via the sixth shut-off valve 22, enabling the helium gas separated by the gas-liquid separator 13 to be transported to the gas storage cylinder 23 for recovery and storage.

[0051] It should be noted that low-temperature plate-fin heat exchangers and microchannel heat exchangers are small in size and light in weight, making them ideal for use in space-constrained environments. Furthermore, these heat exchangers have a compact structure and provide a large heat exchange area, making the transfer of heat energy from the gas to the cooling medium more efficient. Therefore, in this embodiment, the condenser 12 can be a low-temperature plate-fin heat exchanger or a microchannel heat exchanger.

[0052] It should be noted that during the pre-cooling process of liquid hydrogen, tiny liquid particles may mix with the gas. Therefore, in this embodiment, the gas-liquid separator 13 adopts a centrifugal gas-liquid separation structure, which can use centrifugal force to separate these liquid particles from the gas, thereby improving the separation efficiency.

[0053] In the system of this invention, if the high-pressure helium gas in the high-pressure helium cylinder 25 is too hot, it may cause safety problems. Therefore, the high-pressure helium cylinder 25 is immersed in the liquid carbon dioxide tank 14. The temperature of liquid carbon dioxide is much lower than room temperature, and immersing the high-pressure helium cylinder 25 in it can quickly lower the temperature of the helium gas, providing a lower starting temperature for further cooling processes.

[0054] In the system of this invention, the front end of the helium pipeline 24 is connected to the high-pressure helium cylinder 25 via the seventh shut-off valve 26, and the rear end of the helium pipeline 24 is divided into two branches. One branch passes through the dry channel 27 of the dew point cooler and then enters the circulation pipeline 11 to further cool the helium in the pipeline for deep displacement. The other branch passes through the wet channel 28 of the dew point cooler and the eighth shut-off valve 29 before entering the circulation pipeline 11 to separate the helium and carbon dioxide.

[0055] It should be noted that the main function of a dew point cooler is to lower the temperature of a gas by cooling it until it reaches the dew point temperature, which is the temperature at which the gas condenses into a liquid. During this process, water vapor or other impurities in the gas condense into droplets and can be removed, ensuring the purity of the liquid hydrogen. The dew point cooler consists of a dry channel 27 and a wet channel 28. Liquid carbon dioxide from the first shut-off valve 16 enters the wet channel 28 and forms a wetted surface. High-pressure helium from the high-pressure helium cylinder 25 flows through the wetted surface, causing the liquid carbon dioxide to evaporate and mix with the helium before flowing out. The resulting cooling effect cools the helium inside the dry channel 27. It should also be noted that liquid carbon dioxide can also be obtained by directly freezing and capturing atmospheric carbon dioxide using cryogenic hydrogen.

[0056] In the system of the present invention, the circulation pipeline 11 and the helium pipeline 24 are connected by a branch equipped with a first shut-off valve 16, so that liquid carbon dioxide enters the helium pipeline 24 through the circulation pipeline 11.

[0057] In the system of the present invention, the fuel cell 31 is connected to the circulation pipeline 11 through a branch equipped with a ninth shut-off valve 30, so that the fuel cell 31 can receive deeply cooled hydrogen to generate electricity.

[0058] In the system of the present invention, the cryogenic hydrogen pipeline 32 is sequentially connected to the liquid hydrogen storage tank group 33, the tenth shut-off valve 34, the second channel of the condenser 12, and then to the fuel cell 31, so that the fuel cell 31 can receive carbon dioxide liquefied from the cryogenic hydrogen generated by the liquid hydrogen storage tank group 33 for power generation.

[0059] As an extremely low-temperature liquid, thermal management is crucial during the storage and transportation of liquid hydrogen. To maintain the low temperature during liquid hydrogen transportation and reduce heat loss, in this embodiment, the liquid hydrogen filling pipeline 1, circulation pipeline 11, liquid hydrogen filling tank 9, and liquid carbon dioxide tank 14 are all equipped with heat insulation materials to prevent heat loss.

[0060] In the system of this invention, the liquid hydrogen supply tank 2 employs a self-pressurizing method for liquid hydrogen delivery. This self-pressurizing method automatically adjusts the pressure according to the consumption of liquid hydrogen, eliminating the need for external energy or complex control systems, reducing reliance on pumps and other mechanical equipment, and lowering energy consumption and maintenance costs. Furthermore, since the liquid hydrogen is delivered within a closed system using its own pressure, the risk of leakage and external contamination is reduced.

[0061] This invention also provides a method for using a rapid precooling system of a liquid hydrogen refueling station, comprising a start-up phase, a primary replacement and precooling phase, a deep replacement and precooling phase, a liquid hydrogen precooling phase, and a refueling phase. It is assumed that in the initial phase, all valves are closed and all equipment is in a stopped state.

[0062] S1: Startup Phase

[0063] When the tenth shut-off valve 34 is opened, the cryogenic hydrogen from the liquid hydrogen storage tank group 33 enters the cryogenic hydrogen pipeline 32, passes through the tenth shut-off valve 34 and enters the second channel of the condenser 12 to release cold energy, and then enters the fuel cell 31 to generate electricity.

[0064] S2: Primary displacement and precooling stage:

[0065] Open the liquid hydrogen valve 5, the second liquid hydrogen shut-off valve 8, the fourth shut-off valve 19, the second shut-off valve 17, the third shut-off valve 18, and the fifth shut-off valve 21 in the valve subsystem 4. Start the gas-liquid separator 13 and the circulation pump 15. Driven by the circulation pump 15, the liquid carbon dioxide in the liquid carbon dioxide tank 14 enters the liquid hydrogen filling pipeline 1 through the second shut-off valve 17 and the third shut-off valve 18 in sequence, displacing and cooling the valve subsystem 4 and the liquid hydrogen filling tank 9, so that the liquid carbon dioxide is converted into gaseous carbon dioxide.

[0066] Gaseous carbon dioxide enters the first channel of condenser 12 through the fourth shut-off valve 19 to absorb cooling and liquefy, and then enters gas-liquid separator 13. Under the action of gas-liquid separator 13, the unliquefied carbon dioxide gas returns to the circulation pipeline 11 through the fifth shut-off valve 21 to absorb cooling, while the liquid carbon dioxide enters liquid carbon dioxide tank 14. This process is repeated until the temperature of pipe and valve subsystem 4 and liquid hydrogen filling tank 9 are both at the temperature of liquid carbon dioxide. At this time, the preliminary replacement and pre-cooling stage is completed, and the second shut-off valve 17 and the fifth shut-off valve 21 are closed.

[0067] S3: Deep Displacement and Pre-cooling Stage:

[0068] Open the first shut-off valve 16, the sixth shut-off valve 22, the seventh shut-off valve 26, and the eighth shut-off valve 29. Start the circulation pump 15. Liquid carbon dioxide in the liquid carbon dioxide tank 14 enters the wet passage 28 of the dew point cooler through the first shut-off valve 16. Cryogenic helium from the high-pressure helium cylinder 25 enters the wet passage 28 of the dew point cooler after passing through the seventh shut-off valve 26. Liquid carbon dioxide in the dew point cooler diffuses and evaporates into the cryogenic helium, generating cooling. The resulting mixture enters the circulation pipeline 11 through the eighth shut-off valve 29. Another portion of the cryogenic helium enters the dry channel 27 of the dew point cooler, absorbs the cold energy in the wet channel 28, and is further cooled. It then undergoes deep replacement and cooling of the pipe valve subsystem 4 and the liquid hydrogen filling tank 9 through the third shut-off valve 18. Subsequently, it merges with the mixed gas from the wet channel 28 through the fourth shut-off valve 19 and enters the first channel of the condenser 12 to absorb the cold energy. The carbon dioxide in the mixed gas is liquefied again. Under the action of the gas-liquid separator 13, the liquid carbon dioxide in the mixed gas enters the liquid carbon dioxide tank 14, while the helium enters the gas storage cylinder 23 for storage through the sixth shut-off valve 22.

[0069] Continue the above process until the purity of the gas after replacement meets the requirements. Then stop the gas-liquid separator 13 and the circulation pump 15, and close the first shut-off valve 16, the third shut-off valve 18, the fourth shut-off valve 19, the sixth shut-off valve 22, the seventh shut-off valve 26 and the eighth shut-off valve 29. The replacement is then complete.

[0070] S4: Liquid hydrogen precooling stage:

[0071] Open the first liquid hydrogen shut-off valve 3 and the ninth shut-off valve 30. Liquid hydrogen supply tank 2 enters a low-pressure state through self-pressurization. Under the pressure difference, liquid hydrogen flows through the first liquid hydrogen shut-off valve 3 into the pipe and valve subsystem 4 and the liquid hydrogen refueling tank 9 for further pre-cooling. The generated hydrogen gas then flows through the ninth shut-off valve 30 into the fuel cell 31 to supply power. This process continues until the temperatures of the pipe and valve subsystem 4 and the liquid hydrogen refueling tank 9 are both at liquid hydrogen temperature, at which point liquid hydrogen pre-cooling is complete.

[0072] S5: Betting Phase

[0073] Liquid hydrogen supply tank 2 enters a high-pressure state through self-pressurization, initiating the filling process. A large amount of liquid hydrogen enters the pipe and valve subsystem 4 and liquid hydrogen filling tank 9 through the first liquid hydrogen shut-off valve 3. The hydrogen generated during the filling process continues to enter the fuel cell 31 to supply power through the ninth shut-off valve 30. When the liquid hydrogen inside the liquid hydrogen filling tank 9 reaches the set level, the filling is complete. The vent valve 10 is opened, and the first liquid hydrogen shut-off valve 3, the liquid hydrogen valve 5 in the pipe and valve subsystem 4, the second liquid hydrogen shut-off valve 8, the ninth shut-off valve 30, and the tenth shut-off valve 34 are closed, stopping the fuel cell 31 from operating.

[0074] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, all technical solutions obtained through equivalent substitution or transformation fall within the protection scope of the present invention.

Claims

1. A rapid precooling system for a liquid hydrogen refueling station, characterized in that, It includes a liquid hydrogen refueling pipeline (1), a liquid hydrogen supply tank (2), a valve subsystem (4), a liquid hydrogen refueling tank (9), a circulation pipeline (11), a condenser (12), a gas-liquid separator (13), a liquid carbon dioxide tank (14), a gas storage cylinder (23), a helium pipeline (24), a high-pressure helium cylinder (25), a fuel cell (31), a cryogenic hydrogen pipeline (32), and a liquid hydrogen storage tank group (33); The liquid hydrogen filling pipeline (1) is connected in sequence to the liquid hydrogen supply tank (2), the first liquid hydrogen shut-off valve (3), the pipe and valve subsystem (4), the second liquid hydrogen shut-off valve (8), and the liquid hydrogen filling tank (9), transferring the liquid hydrogen medium from the liquid hydrogen supply tank (2) to the liquid hydrogen filling tank (9); the liquid hydrogen filling tank (9) is provided with an air vent valve (10) at the top; The circulation pipeline (11) is connected in sequence to the liquid hydrogen filling tank (9), the fourth shut-off valve (19), the first channel of the condenser (12), the gas-liquid separator (13), the liquid carbon dioxide tank (14), the circulation pump (15), the second shut-off valve (17), and the third shut-off valve (18) to the liquid hydrogen filling pipeline (1), so as to realize the circulation liquefaction of carbon dioxide medium. The outlet of the gas-liquid separator (13) is provided with a secondary circulation pipeline (20); the rear end of the secondary circulation pipeline (20) is divided into two branches. One branch is connected to the circulation pipeline (11) through the fifth shut-off valve (21) to realize the secondary circulation of unliquefied carbon dioxide gas; the other branch is connected to the gas storage cylinder (23) through the sixth shut-off valve (22) to realize the recovery and storage of helium. The high-pressure helium cylinder (25) is immersed in a liquid carbon dioxide tank (14) to lower its temperature; the front end of the helium pipeline (24) is connected to the high-pressure helium cylinder (25) through the seventh shut-off valve (26); the rear end of the helium pipeline (24) is divided into two branches. One branch passes through the dry channel (27) of the dew point cooler and then enters the circulation pipeline (11) to further cool the helium in the pipeline for deep replacement. The other branch passes through the wet channel (28) of the dew point cooler and the eighth shut-off valve (29) and then enters the circulation pipeline (11) to separate the helium and carbon dioxide. The circulation pipeline (11) and the helium pipeline (24) are connected by a branch with a first shut-off valve (16), so that liquid carbon dioxide enters the helium pipeline (24) through the circulation pipeline (11); the fuel cell (31) is connected to the circulation pipeline (11) through a branch with a ninth shut-off valve (30) to receive deeply cooled hydrogen for power generation. The cryogenic hydrogen pipeline (32) is connected in sequence to the liquid hydrogen storage tank group (33), the tenth shut-off valve (34), the second channel of the condenser (12), and then to the fuel cell (31), so that the fuel cell (31) receives carbon dioxide liquefied from the cryogenic hydrogen generated by the liquid hydrogen storage tank group (33) for power generation.

2. The rapid precooling system for a liquid hydrogen refueling station according to claim 1, characterized in that, The valve subsystem (4) includes a liquid hydrogen valve (5) and a liquid hydrogen metering element (7).

3. The rapid precooling system for a liquid hydrogen refueling station according to claim 2, characterized in that, The liquid hydrogen valve (5) is a ball valve, a gate valve, a regulating valve, or a safety valve.

4. The rapid precooling system for a liquid hydrogen refueling station according to claim 2, characterized in that, The liquid hydrogen metering element (7) is a mass flow meter, level gauge, flow rate meter, temperature sensor or pressure sensor.

5. The rapid precooling system for a liquid hydrogen refueling station according to claim 1, characterized in that, The valve subsystem (4) also includes a liquid hydrogen functional component (6) disposed between the liquid hydrogen valve (5) and the liquid hydrogen metering element (7); the liquid hydrogen functional component (6) is a pressure regulating component, a temperature regulating component, or a pump component.

6. The rapid precooling system for a liquid hydrogen refueling station according to claim 1, characterized in that, The liquid hydrogen filling pipeline (1), circulation pipeline (11), liquid hydrogen filling tank (9), and liquid carbon dioxide tank (14) are all equipped with heat insulation materials to prevent heat leakage.

7. The rapid precooling system for a liquid hydrogen refueling station according to claim 1, characterized in that, The liquid hydrogen supply tank (2) delivers liquid hydrogen by means of self-pressurization.

8. The rapid precooling system for a liquid hydrogen refueling station according to claim 1, characterized in that, The condenser (12) is a low-temperature plate-fin heat exchanger or a microchannel heat exchanger.

9. The rapid precooling system for a liquid hydrogen refueling station according to claim 1, characterized in that, The gas-liquid separator (13) adopts a centrifugal gas-liquid separation structure to improve separation efficiency.

10. A method for using the rapid precooling system of a liquid hydrogen refueling station according to any one of claims 1 to 9, characterized in that, In the initial stage, all valves are closed and all devices are stopped. S1: Startup Phase When the tenth shut-off valve (34) is opened, the cryogenic hydrogen from the liquid hydrogen storage tank group (33) enters the cryogenic hydrogen pipeline (32), and enters the second channel of the condenser (12) through the tenth shut-off valve (34) to release the cold energy, and then enters the fuel cell (31) to generate electricity; S2: Primary displacement and precooling stage: Open the liquid hydrogen valve (5), the second liquid hydrogen shut-off valve (8), the fourth shut-off valve (19), the second shut-off valve (17), the third shut-off valve (18), and the fifth shut-off valve (21) in the pipe valve subsystem (4); start the gas-liquid separator (13) and the circulation pump (15). Driven by the circulation pump (15), the liquid carbon dioxide in the liquid carbon dioxide tank (14) enters the liquid hydrogen filling pipeline (1) through the second shut-off valve (17) and the third shut-off valve (18) in sequence, replacing and cooling the pipe valve subsystem (4) and the liquid hydrogen filling tank (9), so that the liquid carbon dioxide is converted into gaseous carbon dioxide. Gaseous carbon dioxide enters the first channel of the condenser (12) through the fourth shut-off valve (19) to absorb cold energy and liquefy, and then enters the gas-liquid separator (13); under the action of the gas-liquid separator (13), the unliquefied carbon dioxide gas returns to the circulation pipeline (11) through the fifth shut-off valve (21) to absorb cold energy, while the liquid carbon dioxide enters the liquid carbon dioxide tank (14). This process repeats until the temperature of the pipe valve subsystem (4) and the liquid hydrogen filling tank (9) are both the temperature of liquid carbon dioxide. At this time, the initial replacement and pre-cooling stage is completed, and the second shut-off valve (17) and the fifth shut-off valve (21) are closed. S3: Deep Displacement and Pre-cooling Stage: Open the first shut-off valve (16), the sixth shut-off valve (22), the seventh shut-off valve (26), and the eighth shut-off valve (29); start the circulation pump (15), and the liquid carbon dioxide in the liquid carbon dioxide tank (14) enters the wet passage (28) of the dew point cooler through the first shut-off valve (16); the low-temperature helium from the high-pressure helium cylinder (25) enters the wet passage (28) of the dew point cooler after passing through the seventh shut-off valve (26), and the liquid carbon dioxide in the dew point cooler diffuses and evaporates into the low-temperature helium to generate cooling, and the resulting mixture enters the circulation pipeline (11) through the eighth shut-off valve (29); the other part of the low-temperature helium... Warm helium enters the dry channel (27) of the dew point cooler, absorbs the cold energy in the wet channel (28) and is further cooled. It then undergoes deep replacement and cooling of the pipe valve subsystem (4) and liquid hydrogen filling tank (9) through the third shut-off valve (18). Subsequently, it merges with the mixed gas from the wet channel (28) through the fourth shut-off valve (19) and enters the first channel of the condenser (12) to absorb the cold energy. The carbon dioxide in the mixed gas is liquefied again. Under the action of the gas-liquid separator (13), the liquid carbon dioxide in the mixed gas enters the liquid carbon dioxide tank (14), while the helium enters the gas storage cylinder (23) through the sixth shut-off valve (22) for storage. Continue the above process until the purity of the gas after replacement meets the requirements. Then stop the gas-liquid separator (13) and the circulating pump (15), and close the first shut-off valve (16), the third shut-off valve (18), the fourth shut-off valve (19), the sixth shut-off valve (22), the seventh shut-off valve (26) and the eighth shut-off valve (29). Replacement is complete. S4: Liquid hydrogen precooling stage: Open the first liquid hydrogen shut-off valve (3) and the ninth shut-off valve (30); the liquid hydrogen supply tank (2) enters a low-pressure state through self-pressurization. Under the action of pressure difference, liquid hydrogen enters the pipe valve subsystem (4) and liquid hydrogen filling tank (9) through the first liquid hydrogen shut-off valve (3) to continue pre-cooling. The generated hydrogen enters the fuel cell (31) to supply power through the ninth shut-off valve (30). Continue the above process until the temperature of the pipe valve subsystem (4) and the liquid hydrogen filling tank (9) are both liquid hydrogen temperature, and the liquid hydrogen pre-cooling is completed. S5: Betting Phase The liquid hydrogen supply tank (2) enters a high-pressure state through self-pressurization and begins the filling process; a large amount of liquid hydrogen enters the pipe valve subsystem (4) and liquid hydrogen filling tank (9) through the first liquid hydrogen shut-off valve (3), and the hydrogen generated during the filling process continues to enter the fuel cell (31) to supply power through the ninth shut-off valve (30). When the liquid hydrogen inside the liquid hydrogen filling tank (9) reaches the set liquid level, the filling is completed; the vent valve (10) is opened, and the first liquid hydrogen shut-off valve (3), the liquid hydrogen valve (5) in the pipe valve subsystem (4), the second liquid hydrogen shut-off valve (8), the ninth shut-off valve (30) and the tenth shut-off valve (34) are closed, and the fuel cell (31) stops operating.

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