A high-pressure gas hydrogen and liquid hydrogen combined refueling system and method for recycling liquid hydrogen cold energy

Abstract

The application belongs to the field of liquid hydrogen storage and filling, and discloses a high-pressure gaseous hydrogen and liquid hydrogen combined filling system and method for recycling liquid hydrogen cold energy, which comprises a high-pressure gaseous hydrogen filling system, a liquid hydrogen filling and BOG treatment system, a liquid hydrogen cold energy recycling system with circulating gas as a cold carrier, and a hydrogen liquefaction system. Different liquid hydrogen pressurization pressures are set to realize high-pressure gaseous hydrogen and liquid hydrogen combined filling. The liquid hydrogen cold energy is recycled by heat exchange between circulating gas and liquid hydrogen. The recycled liquid hydrogen cold energy is used for hydrogen liquefaction precooling, which reduces the hydrogen liquefaction energy consumption cost and realizes liquid hydrogen self-supply in a hydrogen filling station. The liquid hydrogen cold energy is used for high-pressure gaseous hydrogen cooling, which reduces the high-pressure gaseous hydrogen filling cooling energy consumption. The high-pressure liquid hydrogen and boil-off gas are introduced into an ejector to realize boil-off gas recondensation. The system can realize low-energy-consumption liquid hydrogen self-supply in a hydrogen filling station by comprehensive utilization of liquid hydrogen cold energy, and provides a new solution to the liquid hydrogen cold energy utilization and boil-off gas treatment problems in a liquid hydrogen filling station.

Description

Technical Field

[0001] The present invention belongs to the field of liquid hydrogen storage and filling, and in particular relates to a high-pressure gaseous hydrogen and liquid hydrogen combined filling system and method for recovering liquid hydrogen cold energy. Background Art

[0002] Hydrogen fuel cells are considered a highly promising power source, particularly in the transportation sector, and are experiencing rapid growth. Therefore, developing safe, efficient, and energy-efficient hydrogen refueling technologies is of great engineering value. Hydrogen refueling stations primarily offer two types of refueling: high-pressure gaseous hydrogen and liquid hydrogen. Liquid hydrogen refueling stations occupy a smaller footprint, offer increased safety, and lower transportation costs. With the development of the hydrogen energy industry and advancements in hydrogen liquefaction technology, liquid hydrogen refueling stations are likely to become mainstream. Currently, hydrogen storage methods used in hydrogen vehicles include 35MPa high-pressure gas cylinders, 70MPa high-pressure gas cylinders, and liquid hydrogen. Therefore, hydrogen refueling stations still offer both high-pressure gaseous and liquid hydrogen refueling. Liquid hydrogen offers the advantages of flexible and diverse hydrogen supply due to its high pressurization efficiency, low energy consumption, and the ability to accommodate both high-pressure gaseous and liquid hydrogen refueling modes. However, liquid hydrogen refueling stations require solutions to address issues such as liquid hydrogen storage, pressurization, boil-off gas treatment, and liquid hydrogen cooling energy recovery, posing greater technical challenges.

[0003] Boiling off gas (BOG) is evaporated hydrogen produced during the storage and transportation of liquid hydrogen due to factors such as heat leakage and flash evaporation. BOG can cause overpressure in liquid hydrogen storage tanks, which, if not addressed promptly, can pose a safety hazard. Currently, the most common methods for handling BOG at hydrogen refueling stations are direct discharge or compression to 45 MPa for refueling. Direct compression involves compressing the BOG from the tank pressure of 0.1-0.2 MPa to 45 MPa, resulting in a high pressure ratio and high energy consumption, as well as a small and unstable BOG volume. Therefore, this solution is uneconomical in terms of both energy consumption and equipment investment.

[0004] Liquid hydrogen releases a large amount of cold energy during its vaporization process. The proper recovery of this cold energy is crucial for reducing the energy consumption of liquid hydrogen refueling stations. Currently, a variety of novel solutions for recovering and utilizing liquid hydrogen cold energy and treating boil-off gases (BOG) in liquid hydrogen refueling stations have been proposed. For example, Chinese patent application number CN115013721A discloses a high-efficiency hydrogenation system and method for liquid hydrogen refueling stations. This system, which recondenses the BOG by separately pressurizing liquid hydrogen and then mixing them, recovers the liquid hydrogen cold energy and uses it to cool the high-pressure hydrogen being refueled. Chinese patent application CN108561749A discloses a hybrid refueling system for liquid hydrogen refueling stations. This system compresses boil-off gas (BOG) using a compressor and temporarily stores it in a storage tank, utilizing liquid hydrogen cooling energy to lower both the BOG compression temperature and the temperature of the refueled high-pressure hydrogen. In these solutions, the BOG treatment scheme still uses a compressor to compress the BOG, failing to reduce the additional equipment investment associated with the BOG. ​​Chinese patent application CN117287628A discloses a pressurized liquid hydrogen refueling station and its operating method. This scheme uses a solid cold box to store liquid hydrogen cooling energy for hydrogen compression and cooling, as well as for refueling high-pressure hydrogen. However, this scheme uses all of the liquid hydrogen cooling energy in higher temperature zones, resulting in inefficient utilization of valuable low-temperature cooling energy. Chinese patent application CN217875296U discloses a cascaded cold energy recovery system for liquid hydrogen refueling stations. This system utilizes nitrogen, carbon dioxide, and ethylene glycol solutions as working fluids to achieve three-stage recovery of liquid hydrogen cooling energy. However, this scheme is complex, fails to address the issue of temperature-zone application of liquid hydrogen cooling energy, and fails to propose a more suitable BOG treatment solution.

[0005] It can be seen that the existing liquid hydrogen refueling stations mostly use compressors to compress the liquid hydrogen boil-off gas, which requires the installation of additional dynamic machinery, resulting in high energy consumption of the overall system and huge energy loss. Summary of the Invention

[0006] The present invention provides a high-pressure gas-liquid hydrogen combined filling system and method for recovering liquid hydrogen cold energy, so as to solve the technical problem that the existing liquid hydrogen filling stations mostly use a compressor to compress the liquid hydrogen boil-off gas, which requires the addition of additional dynamic machinery, resulting in high energy consumption of the entire system and huge energy loss.

[0007] In order to achieve the above object, the present invention adopts the following technical contents:

[0008] A high-pressure gas-hydrogen and liquid-hydrogen combined filling system for recovering liquid hydrogen cold energy, comprising a high-pressure gas-hydrogen filling system, a liquid hydrogen filling and BOG treatment system, a liquid hydrogen cold energy recovery system with circulating gas cooling, and a hydrogen liquefaction system;

[0009] The high-pressure gas-hydrogen filling system is used to pressurize the liquid hydrogen output by the hydrogen liquefaction system to achieve high-pressure gas-hydrogen filling;

[0010] The liquid hydrogen filling and BOG treatment system is used to process the liquid hydrogen boil-off gas output by the hydrogen liquefaction system and realize liquid hydrogen filling;

[0011] The circulating gas-cooled liquid hydrogen cold energy recovery system is used to realize liquid hydrogen cold energy recovery by exchanging heat between the circulating gas and the low-temperature and high-pressure liquid hydrogen in the high-pressure gas-hydrogen filling system;

[0012] The hydrogen liquefaction system is used to pre-cool the raw high-purity hydrogen gas using the cold energy recovered by the liquid hydrogen cold energy recovery system carried by circulating gas, and then liquefy the raw high-purity hydrogen gas to output liquid hydrogen;

[0013] The liquid hydrogen filling and BOG treatment system includes: a connected ejector and a medium-pressure liquid hydrogen storage tank;

[0014] The liquid hydrogen boil-off gas output by the hydrogen liquefaction system serves as the ejected fluid of the ejector; the hydrogen liquefaction system is connected to the working fluid inlet of the ejector via a low-pressure liquid hydrogen pump;

[0015] The liquid hydrogen boil-off gas is mixed with the low-pressure liquid hydrogen pressurized by the hydrogen liquefaction system through the ejector, and the liquid hydrogen boil-off gas enters the medium-pressure liquid hydrogen storage tank after condensation;

[0016] The liquid hydrogen in the medium-pressure liquid hydrogen storage tank is used for liquid hydrogen filling or provides liquid hydrogen supplement for the hydrogen liquefaction system after being depressurized.

[0017] Furthermore, the hydrogen liquefaction system includes a low-pressure liquid hydrogen storage tank, a first heat exchanger, a second heat exchanger, a third heat exchanger, a fourth heat exchanger, a fifth heat exchanger, a sixth heat exchanger, a helium compressor unit, a stage aftercooler, a seventh heat exchanger, an eighth heat exchanger, a ninth heat exchanger, a first cryogenic helium expander, a second cryogenic helium expander, and a third cryogenic helium expander;

[0018] The hot side inlet of the first heat exchanger is connected to the raw high-purity hydrogen source, and the hot side outlet of the first heat exchanger is sequentially connected to the hot side inlet of the second heat exchanger, the hot side inlet of the third heat exchanger, the hot side inlet of the fourth heat exchanger, the hot side inlet of the fifth heat exchanger, the hot side inlet of the sixth heat exchanger, the first valve, and the ejector working fluid inlet;

[0019] The medium-pressure liquid hydrogen storage tank is connected to the low-pressure liquid hydrogen storage tank through a throttle valve;

[0020] The top of the low-pressure liquid hydrogen storage tank is connected to the ejector;

[0021] The low-pressure liquid hydrogen storage tank is connected to the working fluid inlet of the ejector through a third valve and a low-pressure liquid hydrogen pump, and is also connected to the high-pressure gas hydrogen filling system;

[0022] The high-pressure helium outlet of the helium compressor unit is connected to the stage aftercooler, and the stage aftercooler outlet is respectively connected to the hot side inlet of the seventh heat exchanger, the hot side inlet of the eighth heat exchanger, and the hot side inlet of the ninth heat exchanger;

[0023] The hot side outlet of the seventh heat exchanger, the hot side outlet of the eighth heat exchanger, and the hot side outlet of the ninth heat exchanger are respectively connected to the inlet of the first cryogenic helium expander, the inlet of the second cryogenic helium expander, and the inlet of the third cryogenic helium expander;

[0024] The first low-temperature helium expander outlet, the second low-temperature helium expander outlet, and the third low-temperature helium expander outlet are respectively connected to the cold side inlet of the fourth heat exchanger, the cold side inlet of the fifth heat exchanger, and the cold side inlet of the sixth heat exchanger;

[0025] The cold side outlet of the fourth heat exchanger, the cold side outlet of the fifth heat exchanger, and the cold side outlet of the sixth heat exchanger are connected to the cold side inlet of the seventh heat exchanger, the cold side inlet of the eighth heat exchanger, and the cold side inlet of the ninth heat exchanger respectively;

[0026] The cold side outlet of the seventh heat exchanger, the cold side outlet of the eighth heat exchanger, and the cold side outlet of the ninth heat exchanger are connected to the low-pressure inlet of the helium compressor unit.

[0027] Furthermore, the hot runners of the first heat exchanger, the second heat exchanger, the third heat exchanger, the fourth heat exchanger and the fifth heat exchanger are all filled with ortho-parahydrogen conversion catalysts, and a continuous conversion method is used to catalyze the conversion of orthohydrogen to parahydrogen.

[0028] Furthermore, the high-pressure gas hydrogen filling system includes a first low-temperature liquid hydrogen pump and a second low-temperature liquid hydrogen pump respectively connected to the liquid hydrogen output end of the hydrogen liquefaction system; the first low-temperature liquid hydrogen pump is connected to the first liquid hydrogen evaporator, the first high-pressure gas storage cylinder and the filling cooling system in sequence through the liquid hydrogen cold energy recovery system cooled by the circulating gas; the second low-temperature liquid hydrogen pump is connected to the second liquid hydrogen evaporator, the second high-pressure gas storage cylinder and the filling cooler in sequence through the liquid hydrogen cold energy recovery system cooled by the circulating gas.

[0029] Furthermore, the first cryogenic liquid hydrogen pump adopts a 45MPa cryogenic liquid hydrogen pump, and the second cryogenic liquid hydrogen pump adopts a 90MPa cryogenic liquid hydrogen pump; the first high-pressure gas storage cylinder adopts a 45MPa high-pressure gas storage cylinder, and the second high-pressure gas storage cylinder adopts a 90MPa high-pressure gas storage cylinder; the filling cooling system adopts a 35MPa filling cooling system, and the filling cooler adopts a 70MPa filling cooler.

[0030] Furthermore, the 35MPa charging cooling system adopts a vapor compression refrigeration system.

[0031] Furthermore, the liquid hydrogen cold energy recovery system with circulating gas as cooling medium includes a circulating gas compressor, a circulating gas cooler and a cold energy recovery device; the circulating gas outlet of the circulating gas compressor is connected to the circulating gas cooler inlet, the circulating gas cooler outlet is connected to the hot side inlet of the cold energy recovery device, and the hot side outlet of the cold energy recovery device is respectively connected to the hot side inlet of the first liquid hydrogen evaporator and the hot side inlet of the second liquid hydrogen evaporator; the first liquid hydrogen evaporator is connected to the first low-temperature liquid hydrogen pump, and the second liquid hydrogen evaporator is connected to the second low-temperature liquid hydrogen pump; the cold side outlet of the first heat exchanger of the hydrogen liquefaction system is connected to the circulating gas inlet of the circulating gas compressor; the cold side outlet of the second heat exchanger is connected to the cold side inlet of the filling cooler; the cold side outlet of the filling cooler is connected to the circulating gas inlet of the circulating gas compressor; wherein, after being pressurized by the circulating gas compressor, the circulating gas enters the cold energy recovery device, the first liquid hydrogen evaporator, and the second liquid hydrogen evaporator to recover the liquid hydrogen evaporation cold energy, and then enters the hydrogen liquefaction system and the filling cooler to provide cold energy for hydrogen liquefaction pre-cooling and high-pressure hydrogen filling cooling.

[0032] Furthermore, the circulating gas of the circulating gas compressor is an inert gas, and the inert gas is nitrogen or argon.

[0033] A method for operating a high-pressure gas-hydrogen-liquid hydrogen combined filling system for recovering liquid hydrogen cold energy, based on the above-mentioned high-pressure gas-hydrogen-liquid hydrogen combined filling system for recovering liquid hydrogen cold energy, comprising:

[0034] The hydrogen liquefaction system uses the cold energy recovered from the circulating gas to pre-cool the raw high-purity hydrogen, and then liquefies the raw high-purity hydrogen to output liquid hydrogen;

[0035] The high-pressure gas hydrogen filling system pressurizes the liquid hydrogen output by the hydrogen liquefaction system to achieve high-pressure gas hydrogen filling;

[0036] The liquid hydrogen filling and BOG treatment system processes the liquid hydrogen boil-off gas output from the hydrogen liquefaction system and enables liquid hydrogen filling;

[0037] The circulating gas-cooled liquid hydrogen cooling energy recovery system realizes liquid hydrogen cooling energy recovery through heat exchange between the circulating gas and the low-temperature and high-pressure liquid hydrogen in the high-pressure gas-hydrogen filling system;

[0038] The low-pressure liquid hydrogen pump pressurizes the low-pressure liquid hydrogen in the hydrogen liquefaction system;

[0039] The liquid hydrogen boil-off gas output by the hydrogen liquefaction system is mixed with the low-pressure liquid hydrogen pressurized by the hydrogen liquefaction system through an ejector, and the liquid hydrogen boil-off gas is condensed and then enters the medium-pressure liquid hydrogen storage tank;

[0040] Liquid hydrogen is added using liquid hydrogen in a medium-pressure liquid hydrogen storage tank, or the liquid hydrogen is depressurized to replenish the hydrogen liquefaction system.

[0041] Furthermore, after the high-purity hydrogen enters the hydrogen liquefaction system, it is cooled through six stages of heat exchangers. The low-temperature and high-pressure liquid hydrogen at the hot side outlet of the hydrogen liquefaction system enters the ejector as the working fluid, where the evaporated gas is recondensed and then stored in the medium-pressure liquid hydrogen storage tank.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] The present invention provides a high-pressure gas-hydrogen and liquid-hydrogen combined filling system for recovering liquid hydrogen cold energy. The system includes a high-pressure gas-hydrogen filling system, a liquid hydrogen filling and BOG treatment system, a circulating gas-cooled liquid hydrogen cold energy recovery system, and a hydrogen liquefaction system. The system sets different liquid hydrogen boost pressures to achieve high-pressure gas-hydrogen and liquid-hydrogen combined filling; utilizes circulating gas and liquid hydrogen for heat exchange to achieve liquid hydrogen cold energy recovery; uses the recovered liquid hydrogen cold energy for hydrogen liquefaction pre-cooling, reduces the energy consumption cost of hydrogen liquefaction, and achieves self-replenishment of liquid hydrogen at the hydrogen filling station; uses liquid hydrogen cold energy for high-pressure gas-hydrogen cooling, reduces the energy consumption of high-pressure gas-hydrogen filling cooling; and introduces high-pressure liquid hydrogen and boil-off gas into an ejector to achieve boil-off gas recondensation. By comprehensively utilizing liquid hydrogen cold energy, the system can achieve low-energy self-replenishment of liquid hydrogen within the hydrogen filling station, and has the boil-off gas treatment function of the liquid hydrogen filling station without adding external machinery. This provides a new solution to the problems of liquid hydrogen cold energy utilization and boil-off gas treatment in liquid hydrogen filling stations. The use of the system does not require the addition of additional machinery, reducing the energy consumption of the overall system.

[0044] Preferably, in the present invention, circulating gas cooling is utilized to realize efficient and low-cost recovery of liquid hydrogen cooling capacity in liquid hydrogen refueling stations, and the recovered cooling energy is applied to pre-cooling of hydrogen liquefaction and 70MPa high-pressure hydrogen refueling cooling, thereby realizing comprehensive and rational utilization of liquid hydrogen cooling energy in a larger temperature range.

[0045] Preferably, in the present invention, the cold energy of liquid hydrogen in the liquid hydrogen refueling station is recovered and utilized in the hydrogen liquefaction pre-cooling stage, a helium reverse Brayton cryogenic refrigeration system is composed of a helium compressor unit, a stage aftercooler, etc., and the low-temperature cooling capacity obtained by expanding the high-pressure helium is used in the hydrogen liquefaction deep cooling stage, thereby realizing low-energy self-replenishment of liquid hydrogen in the liquid hydrogen refueling station, and providing a new and efficient and reasonable solution for the comprehensive energy utilization of liquid hydrogen refueling stations that use pipeline transportation as the main hydrogen source.

[0046] Preferably, in the present invention, the ejector is used as the key component for BOG pressure boosting and recondensation, the high-pressure liquid hydrogen in the hydrogen liquefaction system is used as the working fluid, and the liquid hydrogen boil-off gas is used as the ejected fluid, so that boil-off gas recondensation is achieved, and boil-off gas treatment of the liquid hydrogen refueling station is completed in a low-energy, low-investment manner.

[0047] Preferably, the present invention proposes a solution for the efficient recovery and utilization of liquid hydrogen cooling energy and the efficient joint filling of high-pressure gaseous hydrogen and liquid hydrogen in liquid hydrogen refueling stations, which has the functions of efficient recovery of liquid hydrogen cooling energy, low-energy self-replenishment of liquid hydrogen, boil-off gas recondensation, 35MPa and 70MPa high-pressure gaseous hydrogen cooling and filling, and liquid hydrogen filling. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a structural block diagram of a high-pressure gas-hydrogen and liquid-hydrogen combined filling system for recovering liquid hydrogen cold energy provided by the present invention.

[0049] Reference numerals:

[0050] 1. Low-pressure liquid hydrogen storage tank; 2. First cryogenic liquid hydrogen pump; 3. Second cryogenic liquid hydrogen pump; 4. First liquid hydrogen evaporator; 5. Second liquid hydrogen evaporator; 6. Cold energy recovery device; 7. First high-pressure gas cylinder; 8. Second high-pressure gas cylinder; 9. First outlet valve; 10. Second outlet valve; 11. First heat exchanger; 12. Second heat exchanger; 13. Third heat exchanger; 14. Fourth heat exchanger; 15. Fifth heat exchanger; 16. Sixth heat exchanger; 17. First valve; 18. Ejector; 1 9. Medium-pressure liquid hydrogen storage tank; 20. Second valve; 21. Helium compressor unit; 22. After-stage cooler; 23. Seventh heat exchanger; 24. Eighth heat exchanger; 25. Ninth heat exchanger; 26. First cryogenic helium expander; 27. Second cryogenic helium expander; 28. Third cryogenic helium expander; 29. ​​Circulating gas compressor; 30. Circulating gas cooler; 31. Filling cooler; 32. Filling cooling system; 33. Low-pressure liquid hydrogen pump; 34. Throttle valve; 35. Third valve. DETAILED DESCRIPTION

[0051] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail in the following specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0053] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0054] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0055] In the description of the embodiments of the present invention, it should be noted that if the terms "upper," "lower," "horizontal," "inner," etc. appear, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the inventive product is typically placed when in use. These terms are merely for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first," "second," etc. are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0056] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0057] In the description of the embodiments of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. 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; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0058] Example 1

[0059] like Figure 1 As shown, this embodiment provides a high-pressure gas-hydrogen and liquid-hydrogen combined filling system for recovering liquid hydrogen cold energy, including a high-pressure gas-hydrogen filling system, a liquid hydrogen filling and BOG treatment system, a liquid hydrogen cold energy recovery system for circulating gas cooling, and a hydrogen liquefaction system. The specific structure is as follows:

[0060] The high-pressure gas hydrogen filling system consists of a low-pressure liquid hydrogen storage tank 1, a first cryogenic liquid hydrogen pump 2, a first liquid hydrogen evaporator 4, a second cryogenic liquid hydrogen pump 3, a second liquid hydrogen evaporator 5, a cold energy recovery device 6, a first high-pressure gas storage cylinder 7, a filling cooling system 32, a second high-pressure gas storage cylinder 8, and a filling cooler 31. The liquid hydrogen in the low-pressure liquid hydrogen storage tank 1 is connected to the first cryogenic liquid hydrogen pump 2 and the second cryogenic liquid hydrogen pump 3 respectively, and the high-pressure outlets of the first cryogenic liquid hydrogen pump 2 and the second cryogenic liquid hydrogen pump 3 are connected to the cold side inlet of the first liquid hydrogen evaporator 4 and the second liquid hydrogen evaporator 4 respectively. The cold side inlet of the evaporator 5 is connected, the cold side outlet of the first liquid hydrogen evaporator 4 is connected to the inlet of the first high-pressure gas storage cylinder 7 through the first cold side flow channel of the cold energy recovery device 6, and the outlet of the first high-pressure gas storage cylinder 7 is connected to the inlet of the first high-pressure gas storage cylinder 7 through the first outlet valve 9 and the filling cooling system 32 to achieve 35MPa high-pressure hydrogen filling. The cold side outlet of the second liquid hydrogen evaporator 5 is connected to the inlet of the second high-pressure gas storage cylinder 8 through the second cold side flow channel of the cold energy recovery device 6, and the outlet of the second high-pressure gas storage cylinder 8 is connected to the inlet of the second high-pressure gas storage cylinder 8 through the second outlet valve 10 and the filling cooler 31 to achieve 70MPa high-pressure hydrogen filling. After pressurization and evaporation, the low-pressure liquid hydrogen is stored in the first high-pressure gas storage cylinder 7 and the second high-pressure gas storage cylinder 8, respectively. The cold energy of liquid hydrogen evaporation is recovered by the circulating gas circulation loop in the first liquid hydrogen evaporator 4, the second liquid hydrogen evaporator 5 and the cold energy recovery device 6. The high-pressure hydrogen in the first high-pressure gas storage cylinder 7 is cooled by the filling cooling system 32 to achieve 35MPa high-pressure hydrogen filling, and the high-pressure hydrogen in the second high-pressure gas storage cylinder 8 is cooled by the filling cooler 31 to achieve 70MPa high-pressure hydrogen filling.

[0061] The liquid hydrogen filling and BOG treatment system consists of a low-pressure liquid hydrogen storage tank 1, a low-pressure liquid hydrogen pump 33, an ejector 18, and a medium-pressure liquid hydrogen storage tank 19. The liquid hydrogen in the low-pressure liquid hydrogen storage tank 1 is connected to the low-pressure liquid hydrogen pump 33 via a third valve 35. The outlet of the low-pressure liquid hydrogen pump 33 is connected to the working fluid inlet of the ejector 18, and the liquid hydrogen boil-off gas BOG enters the ejector 18 as the ejected fluid. After being pressurized by the low-pressure liquid hydrogen pump 33, the low-pressure liquid hydrogen enters the ejector as the working fluid, where it mixes with the liquid hydrogen boil-off gas BOG, the ejected fluid. After the boil-off gas is recondensed, it enters the medium-pressure liquid hydrogen storage tank 19. The liquid hydrogen in the medium-pressure liquid hydrogen storage tank 19 can be used for liquid hydrogen filling or, after being depressurized by the throttle valve 34, used to replenish the liquid hydrogen in the low-pressure liquid hydrogen storage tank 1.

[0062] The liquid hydrogen cold energy recovery system with circulating gas cooling is composed of a circulating gas compressor 29, a circulating gas cooler 30, a cold energy recovery device 6, a first liquid hydrogen evaporator 4, a second liquid hydrogen evaporator 5, a third heat exchanger 13, a second heat exchanger 12, a first heat exchanger 11, and a charging cooler 31. The circulating gas outlet of the circulating gas compressor 29 is connected to the inlet of the circulating gas cooler 30, the outlet of the circulating gas cooler 30 is connected to the hot side inlet of the cold energy recovery device 6, and the hot side outlet of the cold energy recovery device 6 is connected to the first The hot-side inlet of liquid hydrogen evaporator 4 and the hot-side inlet of second liquid hydrogen evaporator 5 are connected. The hot-side outlet of first liquid hydrogen evaporator 4 is connected to the cold-side inlet of third heat exchanger 13. The cold-side outlet of third heat exchanger 13 and the hot-side outlet of second liquid hydrogen evaporator 5 are connected to the cold-side inlet of second heat exchanger 12. The cold-side outlet of second heat exchanger 12 is connected to the cold-side inlet of first heat exchanger 11 and the cold-side inlet of charging cooler 31. The cold-side outlet of first heat exchanger 11 and the cold-side outlet of charging cooler 31 are connected to the circulating gas inlet of circulating gas compressor 29. After being pressurized by circulating gas compressor 29, the circulating gas enters cold energy recovery device 6, first liquid hydrogen evaporator 4, and second liquid hydrogen evaporator 5 to recover the cold energy from liquid hydrogen evaporation. It then enters third heat exchanger 13, second heat exchanger 12, first heat exchanger 11, and charging cooler 31 in sequence to provide cold energy for hydrogen liquefaction pre-cooling and 70 MPa high-pressure hydrogen charging cooling.

[0063] The hydrogen liquefaction system consists of a first heat exchanger 11, a second heat exchanger 12, a third heat exchanger 13, a fourth heat exchanger 14, a fifth heat exchanger 15, a sixth heat exchanger 16, a helium compressor unit 21, a stage aftercooler 22, a seventh heat exchanger 23, an eighth heat exchanger 24, a ninth heat exchanger 25, a first cryogenic helium expander 26, a second cryogenic helium expander 27, a third cryogenic helium expander 28, an ejector 18, a medium-pressure liquid hydrogen storage tank 19, a throttle valve 34, and a low-pressure liquid hydrogen storage tank 1, wherein the hot side inlet of the first heat exchanger 11 is Connect the raw material high-purity hydrogen source, the hot side outlet of the first heat exchanger 11 is connected in sequence to the hot side inlet of the second heat exchanger 12, the hot side inlet of the third heat exchanger 13, the hot side inlet of the fourth heat exchanger 14, the hot side inlet of the fifth heat exchanger 15, the hot side inlet of the sixth heat exchanger 16, the first valve 17 and the working fluid inlet of the ejector 18, the outlet of the ejector 18 is connected to the inlet of the medium-pressure liquid hydrogen storage tank 19, the medium-pressure liquid hydrogen storage tank 19 is connected to the two outlets of the second valve 20 and the throttle valve 34, the throttle valve 34 is connected to the low-pressure liquid hydrogen storage tank 1, and the helium compressor unit 21 is connected to the second valve 20. The high-pressure helium outlet is connected to the stage aftercooler 22, and the stage aftercooler 22 outlet is respectively connected to the hot side inlet of the seventh heat exchanger 23, the hot side inlet of the eighth heat exchanger 24, and the hot side inlet of the ninth heat exchanger 25. The hot side outlet of the seventh heat exchanger 23, the hot side outlet of the eighth heat exchanger 24, and the hot side outlet of the ninth heat exchanger 25 are respectively connected to the inlet of the first low-temperature helium expander 26, the inlet of the second low-temperature helium expander 27, and the inlet of the third low-temperature helium expander 28. The outlet of the first low-temperature helium expander 26, the outlet of the second low-temperature helium expander 27, and the outlet of the third low-temperature helium expander 28 are respectively connected. The outlet of the low-temperature helium expander 28 is respectively connected to the cold side inlet of the fourth heat exchanger 14, the cold side inlet of the fifth heat exchanger 15, and the cold side inlet of the sixth heat exchanger 16. The cold side outlet of the fourth heat exchanger 14, the cold side outlet of the fifth heat exchanger 15, and the cold side outlet of the sixth heat exchanger 16 are respectively connected to the cold side inlet of the seventh heat exchanger 23, the cold side inlet of the eighth heat exchanger 24, and the cold side inlet of the ninth heat exchanger 25. The cold side outlet of the seventh heat exchanger 23, the cold side outlet of the eighth heat exchanger 24, and the cold side outlet of the ninth heat exchanger 25 are connected to the low-pressure inlet of the helium compressor unit 21. After the high-purity hydrogen enters the hydrogen liquefaction system, it is cooled by six stages of heat exchangers in succession. Among them, the low-temperature side cold energy of the first heat exchanger 11, the second heat exchanger 12, and the third heat exchanger 13 comes from the liquid hydrogen cold energy obtained by recycling the circulating gas, and the low-temperature side cold energy of the fourth heat exchanger 14, the fifth heat exchanger 15, and the sixth heat exchanger 16 comes from the cold energy obtained by helium expansion refrigeration in the reverse Brayton cycle. The low-temperature and high-pressure liquid hydrogen at the hot side outlet of the sixth heat exchanger 16 enters the ejector 18 as a working fluid, and the evaporated gas is recondensed in the ejector 18 and then enters the medium-pressure liquid hydrogen storage tank 19 for storage. The liquid hydrogen in the medium-pressure liquid hydrogen storage tank 19 can be filled with liquid hydrogen through the second valve 20, or it can be partially expanded and cooled through the throttle valve 34 and then returned to the low-pressure liquid hydrogen storage tank 1.

[0064] In this embodiment, in order to facilitate the satisfaction of high-pressure hydrogen filling requirements at different pressures, the first cryogenic liquid hydrogen pump 2 adopts a 45MPa cryogenic liquid hydrogen pump, and the second cryogenic liquid hydrogen pump 3 adopts a 90MPa cryogenic liquid hydrogen pump; the first high-pressure gas storage cylinder 7 adopts a 45MPa high-pressure gas storage cylinder, and the second high-pressure gas storage cylinder 8 adopts a 90MPa high-pressure gas storage cylinder; the filling cooling system 32 adopts a 35MPa filling cooling system, and the filling cooler 31 adopts a 70MPa filling cooler 31.

[0065] In this embodiment, it should be noted that: taking the low-pressure liquid hydrogen storage tank 1 as an example, since the entire system provided in this embodiment belongs to a complete large circulation system, the low-pressure liquid hydrogen storage tank 1 is included in the high-pressure gas hydrogen filling system and is also a component of the hydrogen liquefaction system; that is, the repeated components appearing in the above-mentioned two different systems are all common components, realizing the overall system circulation of the high-pressure gas hydrogen and liquid hydrogen combined filling system for recovering liquid hydrogen cold energy.

[0066] In this embodiment, in the first liquid hydrogen evaporator 4, the second liquid hydrogen evaporator 5 and the cold energy recovery device 6, the cold energy of evaporation of high-pressure liquid hydrogen and the cold energy released by heating from the boiling point to room temperature are recovered by the circulating gas; according to the required temperature zone, the cold energy recovered by the circulating gas is successively used for hydrogen liquefaction pre-cooling and high-pressure hydrogen filling cooling in the filling cooler 31.

[0067] In this embodiment, the circulating gas is an inert gas; the inert gas may be nitrogen or argon.

[0068] In this embodiment, the filling cooling system 32 uses a vapor compression refrigeration system to cool the high-pressure hydrogen to -20°C; the filling cooler 31 uses the cold energy of the low-temperature circulating gas at the cold side outlet 12 of the second heat exchanger to cool the high-pressure hydrogen to -40°C.

[0069] In this embodiment, the boil-off gas BOG serving as the ejected fluid of the ejector 18 is drawn out from the top of the low-pressure liquid hydrogen storage tank 1; the high-pressure liquid hydrogen serving as the working fluid of the ejector 18 is composed of two parts: the high-pressure liquid hydrogen at the outlet of the sixth heat exchanger 16 and the high-pressure liquid hydrogen at the outlet of the low-pressure liquid hydrogen pump 33.

[0070] In this embodiment, the high-purity hydrogen required at the inlet of the hydrogen liquefaction system comes from hydrogen transported in a high-pressure pipeline, or is obtained by purifying and compressing low-pressure hydrogen. The hot runners of the first heat exchanger 11, the second heat exchanger 12, the third heat exchanger 13, the fourth heat exchanger 14, and the fifth heat exchanger 15 of the hydrogen liquefaction system are filled with an ortho-para hydrogen conversion catalyst, and a continuous conversion method is used to catalyze the conversion of ortho-hydrogen into para-hydrogen, and finally a high-pressure hydrogen stream with a para-hydrogen ratio of 95% is obtained at the outlet of the fifth heat exchanger 15.

[0071] In this embodiment, the liquid hydrogen in the medium-pressure liquid hydrogen storage tank 19 can be directly used for liquid hydrogen filling, or it can be partially throttled by the throttle valve 34 and then enter the low-pressure liquid hydrogen storage tank 1 to replenish the low-pressure liquid hydrogen therein.

[0072] Example 2

[0073] This embodiment provides an implementation method of a high-pressure gas-hydrogen-liquid hydrogen combined filling system for recovering liquid hydrogen cold energy, that is, a working method. Based on the high-pressure gas-hydrogen-liquid hydrogen combined filling system for recovering liquid hydrogen cold energy provided in Example 1, the specific implementation process is as follows:

[0074] In the high-pressure gas-hydrogen filling system of this embodiment, liquid hydrogen in the low-pressure liquid hydrogen storage tank 1 enters a 45 MPa cryogenic liquid hydrogen pump 2 and a 90 MPa cryogenic liquid hydrogen pump 3, respectively. After being pressurized to 45 MPa and 90 MPa by the cryogenic liquid hydrogen pumps, the liquid hydrogen enters a first liquid hydrogen evaporator 4 and a second liquid hydrogen evaporator 5, respectively. The high-pressure liquid hydrogen is vaporized and heated to 213 K in the first and second liquid hydrogen evaporators 4 and 5, and then further heated to 298.15 K in a cold energy recovery device 6 before being stored in a 45 MPa high-pressure gas cylinder 7 and a 90 MPa high-pressure gas cylinder 8, respectively. When 35MPa high-pressure hydrogen filling is required, the 45MPa high-pressure gas cylinder 7 opens the first outlet valve 9, and the high-pressure hydrogen enters the 35MPa filling cooling system 32. This cooling system uses a vapor compression refrigeration cycle to cool the high-pressure hydrogen from the ambient temperature of 298.15 K to 273.15 K. After the high-pressure hydrogen is cooled to 273.15 K, 35MPa filling is performed. When 70MPa high-pressure hydrogen filling is required, the 90MPa high-pressure gas cylinder 8 opens the second outlet valve 10, and the high-pressure hydrogen enters the 70MPa filling cooler 31. The high-pressure hydrogen in the 70MPa filling cooler 31 is cooled to 233.15 K by the low-temperature circulating gas from the outlet of the second heat exchanger 12. The high-pressure hydrogen at the outlet of the 70MPa filling cooler 31 is then filled at 70MPa.

[0075] In the circulating gas-cooled liquid hydrogen cold energy recovery system of this embodiment, the circulating gas compressor 29 pressurizes the circulating gas from 0.1 MPa to 0.2 MPa to overcome pressure losses in the heat exchanger during the circulating gas circulation process. The high-pressure circulating gas at the outlet of the circulating gas compressor 29 is cooled to 300 K by the circulating gas cooler 30, then enters the cold energy recovery device 6 to be cooled to 219 K by the high-pressure liquid hydrogen. The circulating gas at the outlet of the cold energy recovery device 6 is split by a flow splitter into two streams with mass proportions of 50.06% and 49.94%, respectively, which enter the first liquid hydrogen evaporator 4 and the second liquid hydrogen evaporator 5 to recover liquid hydrogen cold energy. The circulating gas at the outlet of the first liquid hydrogen evaporator 4 is cooled to 81.47 K and then enters the third heat exchanger 13 to provide cold energy for hydrogen liquefaction. The circulating gas at the outlet of the second liquid hydrogen evaporator 5 is cooled to 87.85 K and then mixed with the circulating gas at the outlet of the third heat exchanger 13 before entering the second heat exchanger 12. The low-temperature circulating gas that recovers the cold energy of liquid hydrogen exchanges heat with hydrogen in the third heat exchanger 13 and the second heat exchanger 12. The circulating gas temperatures at the outlets of the third heat exchanger 13 and the second heat exchanger 12 rise to 86.29K and 231K, respectively. The circulating gas at the outlet of the second heat exchanger 12 is split into two streams by a splitter, with mass proportions of 52.25% and 47.75%, respectively. Stream one enters the first heat exchanger 11 to exchange heat with the high-pressure hydrogen at the inlet of the hydrogen liquefaction system, while stream two enters the 70MPa charging cooler 31 to provide cold energy for cooling the high-pressure hydrogen. The circulating gas temperatures at the outlets of the first heat exchanger 11 and the 70MPa charging cooler 31 are 279K and 296K, respectively. The circulating gases at the outlets of the first heat exchanger 11 and the 70MPa charging cooler 31 are mixed and then enter the circulating gas compressor 29, forming a circulating gas cycle.

[0076] In the hydrogen liquefaction system of this embodiment, the high-purity hydrogen required for hydrogen liquefaction comes from high-pressure pipeline hydrogen transportation or is obtained from low-pressure hydrogen through purification and compression. The liquid hydrogen obtained from the hydrogen liquefaction system can supplement the liquid hydrogen required for high-pressure hydrogen refueling. Hydrogen liquefaction mainly consists of two parts: a pre-cooling stage and a cryogenic stage. In the pre-cooling stage, the hydrogen liquefaction system mainly relies on the liquid hydrogen cold energy recovered from the circulating gas to achieve cooling. The hydrogen liquefied stream exchanges heat with the low-temperature circulating gas in the first heat exchanger 11, the second heat exchanger 12, and the third heat exchanger 13, and is cooled to 268.7 K, 95 K, and 83.5 K respectively. In the cryogenic stage, the hydrogen liquefaction system mainly relies on the cold energy obtained from the expansion of low-temperature helium. The hydrogen liquefied stream exchanges heat with the expanded low-temperature helium in the fourth heat exchanger 14, the fifth heat exchanger 15, and the sixth heat exchanger 16, and is cooled to 53.15 K, 33.15 K, and 22.5 K respectively. The high-pressure liquid hydrogen at the outlet of the sixth heat exchanger 16 enters the ejector 18 as the working fluid. In the helium reverse Brayton cycle, the total pressure ratio of the helium compressor unit 21 is 10. A three-stage compression design is selected, and three-stage constant pressure ratio compression is adopted. The exhaust temperature of each compressor is 421.5 K. The helium gas at the outlet of each compressor is cooled to 298.15 K by the after-stage cooler 22, and the exhaust pressure of the last-stage compressor is 1 MPa. The high-pressure helium at the outlet of the helium compressor unit 21 is divided into three streams with mass proportions of 29.56%, 51.25% and 18.19% respectively by the splitter, and enters the seventh heat exchanger 23, the eighth heat exchanger 24 and the ninth heat exchanger 25 respectively to exchange heat with the reflux helium, and is cooled to 77.9 K, 50 K and 34.01 K respectively, and then enters the first low-temperature helium expander 26, the second low-temperature helium expander 27 and the third low-temperature helium expander 28 respectively. The low-temperature helium at the outlet of the expander enters the fourth heat exchanger 14, the fifth heat exchanger 15 and the sixth heat exchanger 16 respectively. After heat exchange with the hydrogen liquefaction stream in the above three heat exchangers, the temperature is raised to 76.4 K, 48.3 K and 32.01 K respectively. K. The helium at the outlets of the fourth, fifth, and sixth heat exchangers 14, 15, and 16 flows as reflux gas into the seventh, eighth, and ninth heat exchangers 23, 24, and 25, respectively. The reflux gases at the outlets of these three heat exchangers are heated to 297.3 K. After mixing, the reflux gases at the outlets of the three heat exchangers enter the helium compressor unit 21, completing the helium cycle. In this embodiment, an ortho-parahydrogen conversion catalyst is filled in the high-pressure hydrogen flow channels of the first, second, third, fourth, and fifth heat exchangers 11, 12, 13, and 14, respectively. A continuous conversion method is used to catalyze the conversion of orthohydrogen to parahydrogen, ultimately producing a high-pressure hydrogen stream containing 95% parahydrogen at the outlet of the fifth heat exchanger 15.

[0077] The core component of the liquid hydrogen filling and BOG treatment system in this embodiment is the ejector 18. In this system, the low-pressure liquid hydrogen storage tank 1 is connected to the low-pressure liquid hydrogen pump 33. The low-pressure liquid hydrogen pump 33 pressurizes the liquid hydrogen to 2.5 MPa and then mixes it with the high-pressure liquid hydrogen at the outlet of the sixth heat exchanger 16. The mixed stream enters the ejector 18 as the working fluid, and the BOG drawn out from the top of the low-pressure liquid hydrogen storage tank 1 enters the ejector 18 as the ejected fluid. The BOG is recondensed in the ejector 18, and the liquid hydrogen at the outlet of the ejector 18 enters the medium-pressure liquid hydrogen storage tank 19 for temporary storage. The liquid hydrogen in the medium-pressure liquid hydrogen storage tank 19 can be directly used for liquid hydrogen filling after pressurization, or it can be partially throttled and depressurized by the throttle valve 34 and then enter the low-pressure liquid hydrogen storage tank 1 for replenishing the liquid hydrogen therein.

[0078] In order to further demonstrate the beneficial effects of this embodiment, Figure 1 Process simulation calculations were performed, and the key operating parameters and key performance evaluation indicators are listed in Table 1. The ambient temperature was 298.15K, and the ambient pressure was 0.1 MPa. The mass flow rates of 45 MPa and 90 MPa high-pressure hydrogen and the mass flow rates of liquefied hydrogen in the hydrogen liquefaction system were set to 100 kg / h, 100 kg / h, and 200 kg / h, respectively. Nitrogen was used as the circulating gas, and the outlet pressure of the circulating gas compressor, the exhaust pressure of the helium compressor, and the outlet pressure of the cryogenic helium expander were set to 0.2 MPa, 1 MPa, and 0.1 MPa, respectively.

[0079] In this embodiment, the 45MPa cryogenic liquid hydrogen pump used to achieve 35MPa high-pressure gas hydrogen refueling has a power of 19.29kW. The 35MPa refueling cooling system uses a vapor compression refrigeration system with an average COP of 3, with a power of 18.84kW. The 90MPa cryogenic liquid hydrogen pump used to achieve 70MPa high-pressure gas hydrogen refueling has a power of 39.72kW. In this embodiment, the required circulating gas and helium mass flow rates are 3246 kg / h and 2113 kg / h, respectively. The ratio of the working fluid to the ejected BOG mass flow rate in the ejector 18 is selected to be 7.5, the BOG processing flow rate is 40 kg / h, and the ejector outlet pressure is 0.74MPa. The main energy-consuming equipment in the hydrogen liquefaction system is the circulating gas compressor and the helium compressor. The sum of their power is the energy consumption of the hydrogen liquefaction system. The specific energy consumption per unit mass of hydrogen liquefaction is the ratio of the hydrogen liquefaction system energy consumption to the hydrogen liquefaction mass flow rate. In this embodiment, the power of the circulating gas compressor is 69.24 kW, the power of the helium compressor unit is 1125 kW, and the calculated specific energy consumption of hydrogen liquefaction is 5.972 kWh / kg.

[0080] Table 1 shows the key operating parameters and key performance evaluation indicators

[0081]

[0082] In summary, the present invention provides a high-pressure gaseous hydrogen and liquid hydrogen combined filling system and method for recovering liquid hydrogen cold energy. Compared with existing filling measures, it has the following advantages:

[0083] This high-pressure gas-hydrogen-liquid hydrogen joint filling system for recovering liquid hydrogen cold energy realizes the efficient and low-cost recovery and comprehensive application of liquid hydrogen cold capacity in liquid hydrogen filling stations through the circulating gas cooling technology. It not only uses the recovered cold energy for pre-cooling of hydrogen liquefaction and high-pressure hydrogen filling cooling, but also realizes low-energy self-replenishment of liquid hydrogen through the helium reverse Brayton low-temperature refrigeration system. At the same time, it uses the ejector to treat the boil-off gas at low cost, and innovatively proposes a high-efficiency joint filling scheme for high-pressure gas-hydrogen and liquid hydrogen, which integrates the functions of efficient recovery of liquid hydrogen cold energy, liquid hydrogen self-replenishment, boil-off gas recondensation, and high-pressure gas-hydrogen cooling and filling, providing a new efficient and economical way for the comprehensive energy utilization of liquid hydrogen filling stations.

[0084] The above embodiment is only one of the implementation methods that can realize the technical solution of the present invention. The scope of protection claimed by the present invention is not limited only to this embodiment, but also includes changes, replacements and other implementation methods that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention.

Claims

1. A high-pressure gaseous hydrogen and liquid hydrogen combined filling system for recovering liquid hydrogen cold energy, characterized in that: It includes high-pressure gas hydrogen filling system, liquid hydrogen filling and BOG treatment system, liquid hydrogen cooling energy recovery system with circulating gas cooling, and hydrogen liquefaction system; The high-pressure gas-hydrogen filling system is used to pressurize the liquid hydrogen output by the hydrogen liquefaction system to achieve high-pressure gas-hydrogen filling; The liquid hydrogen filling and BOG treatment system is used to process the liquid hydrogen boil-off gas output by the hydrogen liquefaction system and realize liquid hydrogen filling; The circulating gas-cooled liquid hydrogen cold energy recovery system is used to realize liquid hydrogen cold energy recovery by exchanging heat between the circulating gas and the low-temperature and high-pressure liquid hydrogen in the high-pressure gas-hydrogen filling system; The hydrogen liquefaction system is used to pre-cool the raw high-purity hydrogen gas using the cold energy recovered by the liquid hydrogen cold energy recovery system carried by circulating gas, and then liquefy the raw high-purity hydrogen gas to output liquid hydrogen; The liquid hydrogen filling and BOG treatment system comprises: an ejector (18) and a medium-pressure liquid hydrogen storage tank (19) connected to each other; The liquid hydrogen boil-off gas output by the hydrogen liquefaction system serves as the ejected fluid of the ejector (18); the hydrogen liquefaction system is connected to the working fluid inlet of the ejector (18) via a low-pressure liquid hydrogen pump (33); The liquid hydrogen boil-off gas is mixed with the low-pressure liquid hydrogen pressurized by the hydrogen liquefaction system through the ejector (18), and the liquid hydrogen boil-off gas is condensed and enters the medium-pressure liquid hydrogen storage tank (19); The liquid hydrogen in the medium-pressure liquid hydrogen storage tank (19) is used for liquid hydrogen refueling or to provide liquid hydrogen supplement for the hydrogen liquefaction system after pressure reduction; The hydrogen liquefaction system comprises a low-pressure liquid hydrogen storage tank (1), a first heat exchanger (11), a second heat exchanger (12), a third heat exchanger (13), a fourth heat exchanger (14), a fifth heat exchanger (15), and a sixth heat exchanger (16); the hot side inlet of the first heat exchanger (11) is connected to a raw material high-purity hydrogen source, and the hot side outlet of the first heat exchanger (11), the second heat exchanger (12), the third heat exchanger (13), the fourth heat exchanger (14), the fifth heat exchanger (15), the sixth heat exchanger (16), the first valve (17), and the working fluid inlet of the ejector (18) are connected in sequence; The medium-pressure liquid hydrogen storage tank (19) is connected to the low-pressure liquid hydrogen storage tank (1) via a throttle valve (34); The top of the low-pressure liquid hydrogen storage tank (1) is connected to the ejector (18); The low-pressure liquid hydrogen storage tank (1) is connected to the working fluid inlet of the ejector (18) through a third valve (35) and a low-pressure liquid hydrogen pump (33), and is also connected to the high-pressure gas hydrogen filling system; Hydrogen liquefaction includes a pre-cooling stage and a cryogenic stage; In the pre-cooling stage, the hydrogen liquefaction system relies on the liquid hydrogen cooling energy recovered from the circulating gas to achieve cooling, and the hydrogen liquefaction stream exchanges heat with the low-temperature circulating gas in the first heat exchanger (11), the second heat exchanger (12), and the third heat exchanger (13) in succession; During the cryogenic stage, the hydrogen liquefaction system relies on the cold energy obtained by the expansion of low-temperature helium. The hydrogen liquefaction stream passes through the fourth heat exchanger (14), the fifth heat exchanger (15), and the sixth heat exchanger (16) in sequence to exchange heat with the expanded low-temperature helium. The high-pressure liquid hydrogen at the outlet of the sixth heat exchanger (16) enters the ejector (18) as a working fluid.

2. The high-pressure gaseous hydrogen and liquid hydrogen combined filling system for recovering liquid hydrogen cold energy according to claim 1 is characterized in that: The hydrogen liquefaction system further includes a helium compressor unit (21), a stage aftercooler (22), a seventh heat exchanger (23), an eighth heat exchanger (24), a ninth heat exchanger (25), a first cryogenic helium expander (26), a second cryogenic helium expander (27), and a third cryogenic helium expander (28); The high-pressure helium outlet of the helium compressor unit (21) is connected to the after-stage cooler (22), and the outlet of the after-stage cooler (22) is respectively connected to the hot side inlet of the seventh heat exchanger (23), the hot side inlet of the eighth heat exchanger (24), and the hot side inlet of the ninth heat exchanger (25); The hot side outlet of the seventh heat exchanger (23), the hot side outlet of the eighth heat exchanger (24), and the hot side outlet of the ninth heat exchanger (25) are respectively connected to the inlet of the first low-temperature helium expander (26), the inlet of the second low-temperature helium expander (27), and the inlet of the third low-temperature helium expander (28); The outlet of the first cryogenic helium expander (26), the outlet of the second cryogenic helium expander (27), and the outlet of the third cryogenic helium expander (28) are respectively connected to the cold side inlet of the fourth heat exchanger (14), the cold side inlet of the fifth heat exchanger (15), and the cold side inlet of the sixth heat exchanger (16); The cold side outlet of the fourth heat exchanger (14), the cold side outlet of the fifth heat exchanger (15), and the cold side outlet of the sixth heat exchanger (16) are respectively connected to the cold side inlet of the seventh heat exchanger (23), the cold side inlet of the eighth heat exchanger (24), and the cold side inlet of the ninth heat exchanger (25); The cold side outlet of the seventh heat exchanger (23), the cold side outlet of the eighth heat exchanger (24), and the cold side outlet of the ninth heat exchanger (25) are connected to the low-pressure inlet of the helium compressor unit (21).

3. The high-pressure gaseous hydrogen and liquid hydrogen combined filling system for recovering liquid hydrogen cold energy according to claim 2 is characterized in that: The hot runners of the first heat exchanger (11), the second heat exchanger (12), the third heat exchanger (13), the fourth heat exchanger (14), and the fifth heat exchanger (15) are all filled with ortho-parahydrogen conversion catalysts, and a continuous conversion method is used to catalyze the conversion of orthohydrogen into parahydrogen.

4. The high-pressure gaseous hydrogen and liquid hydrogen combined filling system for recovering liquid hydrogen cold energy according to claim 2 is characterized in that: The high-pressure gas hydrogen filling system comprises a first low-temperature liquid hydrogen pump (2) and a second low-temperature liquid hydrogen pump (3) respectively connected to the liquid hydrogen output end of the hydrogen liquefaction system; the first low-temperature liquid hydrogen pump (2) is connected in sequence to a first liquid hydrogen evaporator (4), a first high-pressure gas storage cylinder (7) and a filling cooling system (32) through the liquid hydrogen cold energy recovery system cooled by the circulating gas; the second low-temperature liquid hydrogen pump (3) is connected in sequence to a second liquid hydrogen evaporator (5), a second high-pressure gas storage cylinder (8) and a filling cooler (31) through the liquid hydrogen cold energy recovery system cooled by the circulating gas.

5. The high-pressure gaseous hydrogen and liquid hydrogen combined filling system for recovering liquid hydrogen cold energy according to claim 4 is characterized in that: in, The first cryogenic liquid hydrogen pump (2) adopts a 45MPa cryogenic liquid hydrogen pump, and the second cryogenic liquid hydrogen pump (3) adopts a 90MPa cryogenic liquid hydrogen pump; the first high-pressure gas storage cylinder (7) adopts a 45MPa high-pressure gas storage cylinder, and the second high-pressure gas storage cylinder (8) adopts a 90MPa high-pressure gas storage cylinder; the filling cooling system (32) adopts a 35MPa filling cooling system, and the filling cooler (31) adopts a 70MPa filling cooler (31).

6. The high-pressure gaseous hydrogen and liquid hydrogen combined filling system for recovering liquid hydrogen cold energy according to claim 5 is characterized in that: The 35MPa charging cooling system adopts a vapor compression refrigeration system.

7. The high-pressure gaseous hydrogen and liquid hydrogen combined filling system for recovering liquid hydrogen cold energy according to claim 4 is characterized in that: The circulating gas-cooled liquid hydrogen cold energy recovery system comprises a circulating gas compressor (29), a circulating gas cooler (30) and a cold energy recovery device (6); the circulating gas outlet of the circulating gas compressor (29) is connected to the inlet of the circulating gas cooler (30), the circulating gas cooler (30) outlet is connected to the hot side inlet of the cold energy recovery device (6), and the hot side outlet of the cold energy recovery device (6) is respectively connected to the hot side inlet of the first liquid hydrogen evaporator (4) and the hot side inlet of the second liquid hydrogen evaporator (5); the first liquid hydrogen evaporator (4) is connected to the first low-temperature liquid hydrogen pump (2), and the second liquid hydrogen evaporator (5) is connected to the second low-temperature liquid hydrogen pump (3); the hydrogen liquid The cold side outlet of the first heat exchanger (11) of the liquefaction system is connected to the circulating gas inlet of the circulating gas compressor (29); the cold side outlet of the second heat exchanger (12) is connected to the cold side inlet of the filling cooler (31); the cold side outlet of the filling cooler (31) is connected to the circulating gas inlet of the circulating gas compressor (29); wherein, after being pressurized by the circulating gas compressor (29), the circulating gas enters the cold energy recovery device (6), the first liquid hydrogen evaporator (4), and the second liquid hydrogen evaporator (5) to recover the liquid hydrogen evaporation cold energy, and then enters the hydrogen liquefaction system and the filling cooler (31) to provide cold energy for hydrogen liquefaction pre-cooling and high-pressure hydrogen filling cooling.

8. The high-pressure gaseous hydrogen and liquid hydrogen combined filling system for recovering liquid hydrogen cold energy according to claim 7 is characterized in that: The circulating gas of the circulating gas compressor (29) is an inert gas, which is nitrogen or argon.

9. A method for operating a high-pressure gas-hydrogen and liquid-hydrogen combined filling system for recovering liquid hydrogen cold energy, characterized in that: The high-pressure gas-hydrogen and liquid-hydrogen combined filling system for recovering liquid hydrogen cold energy according to any one of claims 1 to 8 comprises: The hydrogen liquefaction system uses the cold energy recovered from the circulating gas to pre-cool the raw high-purity hydrogen, and then liquefies the raw high-purity hydrogen to output liquid hydrogen; The high-pressure gas hydrogen filling system pressurizes the liquid hydrogen output by the hydrogen liquefaction system to achieve high-pressure gas hydrogen filling; The liquid hydrogen filling and BOG treatment system processes the liquid hydrogen boil-off gas output from the hydrogen liquefaction system and enables liquid hydrogen filling; The circulating gas-cooled liquid hydrogen cooling energy recovery system realizes liquid hydrogen cooling energy recovery through heat exchange between the circulating gas and the low-temperature and high-pressure liquid hydrogen in the high-pressure gas-hydrogen filling system; The low-pressure liquid hydrogen pump (33) pressurizes the low-pressure liquid hydrogen in the hydrogen liquefaction system; The liquid hydrogen boil-off gas output from the hydrogen liquefaction system is mixed with the low-pressure liquid hydrogen pressurized by the hydrogen liquefaction system through an ejector, and the liquid hydrogen boil-off gas is condensed and enters the medium-pressure liquid hydrogen storage tank (19); Using the liquid hydrogen in the medium-pressure liquid hydrogen storage tank (19) to fill the liquid hydrogen, or reducing the pressure of the liquid hydrogen to replenish the liquid hydrogen for the hydrogen liquefaction system; After high-purity hydrogen enters the hydrogen liquefaction system, it is cooled by six-stage heat exchangers. The low-temperature and high-pressure liquid hydrogen at the hot side outlet of the hydrogen liquefaction system enters the ejector (18) as the working fluid, and the evaporated gas is recondensed in the ejector (18) and then enters the medium-pressure liquid hydrogen storage tank (19) for storage.

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