Liquefaction equipment, liquefaction systems, hydrogen gas filling systems

Abstract

To provide a technology capable of reducing energy consumption during re-liquefaction of boil-off gas.SOLUTION: A re-liquefaction device 30 according to an embodiment comprises: a low-pressure path L1 through which boil-off gas supplied from a liquid hydrogen storage tank 10 for storing liquid hydrogen flows; a compression unit that compresses the boil-off gas in the low-pressure path L1; a high-pressure path L2 through which the high-temperature boil-off gas flowing out from the compression unit flows; heat exchangers HX that exchange heat between the boil-off gas on the low-temperature side of the low-pressure path L1 and the boil-off gas on the high-temperature side of the high-pressure path L2; a Joule-Thomson valve JT that liquefies, by expansion, at least a part of the boil-off gas in the high-pressure path L2 whose temperature decreased through the heat exchangers HX; and a BOG recovery path 32B that is provided separately from the low-pressure path L1 and allows the boil-off gas supplied from the liquid hydrogen storage tank 10 to pass through the heat exchanger HX1 on the highest-temperature side among the heat exchangers HX as a refrigerant on the low-temperature side.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a liquefaction device and the like.

Background Art

[0002] Conventionally, a technique for reliquefying boil-off gas (BOG) generated from liquid hydrogen has been known (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, reliquefying boil-off gas requires the supply of external energy. Therefore, it is desirable to reduce the energy consumption during reliquefaction of boil-off gas.

[0005] Therefore, in view of the above problems, an object is to provide a technique capable of reducing the energy consumption during reliquefaction of boil-off gas.

Means for Solving the Problems

[0006] To achieve the above object, in one embodiment of the present disclosure, a first path through which boil-off gas supplied from a storage device storing liquid hydrogen flows; a compression unit that compresses the boil-off gas in the first path; a second path through which the high-temperature boil-off gas flowing out from the compression unit flows; a plurality of heat exchange units that perform heat exchange between the low-temperature-side boil-off gas in the first path and the high-temperature-side boil-off gas in the second path; A liquefaction unit that liquefies at least a portion of the boil-off gas in the second path, whose temperature has decreased through the aforementioned multi-stage heat exchange unit, by expansion, A third path is provided separately from the first path, and passes the boil-off gas supplied from the storage device as a low-temperature refrigerant to the first heat exchange section, which is the highest-temperature section among the multiple stages of heat exchange sections. A liquefaction device is provided.

[0007] In other embodiments of this disclosure, The liquefaction apparatus described above, The storage device comprises supplying boil-off gas to the liquefaction device and receiving liquid hydrogen from the liquefaction device after the boil-off gas has been liquefied. A liquefaction system is provided.

[0008] Furthermore, in yet another embodiment of this disclosure, The liquefaction apparatus described above, A storage device that supplies boil-off gas to the liquefaction device and receives liquid hydrogen from the liquefaction device after the boil-off gas has been liquefied, A generator that generates hydrogen gas from liquid hydrogen supplied from the storage device, The device comprises a filling device that fills an object to be filled with hydrogen gas generated by the aforementioned generating device. A hydrogen gas refueling system will be provided. [Effects of the Invention]

[0009] According to the above-described embodiment, energy consumption during the reliquefaction of boil-off gas can be reduced. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows an example of a liquid hydrogen storage system. [Figure 2] This diagram schematically shows the configuration of a first example of a reliquefaction device. [Figure 3] This diagram schematically shows a second example of the configuration of a reliquefaction device. [Figure 4]It is a diagram showing an example of a hydrogen gas filling system.

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments will be described with reference to the drawings.

[0012] In this embodiment, the boil-off gas is described on the premise that it includes all vaporized gases of liquid hydrogen regardless of the cause of generation. For example, the boil-off gas includes gases generated by flashing due to heat input from the outside during storage or transfer of liquid hydrogen. Also, for example, the boil-off gas includes gases generated by evaporation accompanying precooling of the transfer flow path or the storage tank at the transfer destination during transfer of liquid hydrogen. Also, for example, the boil-off gas includes gases generated by flashing accompanying a pressure difference generated during transfer of liquid hydrogen. Flashing accompanying a pressure difference includes, for example, flashing accompanying pressure loss during transfer, flashing by a valve passed through during transfer, flashing accompanying expansion at the time of inflow from the transfer flow path to the storage tank, etc. Also, for example, the boil-off gas includes gases generated by evaporation accompanying the conversion heat of the conversion from ortho-hydrogen, which is a nuclear spin isomer of hydrogen, to para-hydrogen (hereinafter, "ortho-para conversion"). Hereinafter, unless otherwise specified, "equilibrium state" means an equilibrium state regarding the ratio of ortho-hydrogen and para-hydrogen.

[0013] [Liquid Hydrogen Storage System] Referring to FIG. 1, the liquid hydrogen storage system 100 according to this embodiment will be described.

[0014] FIG. 1 is a diagram showing an example of the liquid hydrogen storage system 100.

[0015] As shown in FIG. 1, the liquid hydrogen storage system 100 includes a liquid hydrogen storage tank 10, a liquid hydrogen supply line 20, a reliquefaction device 30, a BOG recovery line 40, and a liquid hydrogen supply line 50.

[0016] The liquid hydrogen storage tank 10 stores liquid hydrogen supplied from the outside through the liquid hydrogen supply line 20.

[0017] The liquid hydrogen storage tank 10 includes an inner tank 11 in which liquid hydrogen is stored and an outer tank 12 that covers the outside of the inner tank 11.

[0018] The outer tank 12 has a heat insulation structure that suppresses heat input to the liquid hydrogen inside the inner tank 11. For example, a vacuum heat insulation layer is provided between the outer tank 12 and the inner tank 11.

[0019] The liquid hydrogen supply line 20 is used to supply liquid hydrogen to the liquid hydrogen storage tank 10 from the outside (the other end), with one end connected to the liquid hydrogen storage tank 10 (inner tank 11).

[0020] The liquid hydrogen supply line 20 includes a main supply line 21 and a precooling line 22.

[0021] The main supply line 21 is used in a state where the liquid hydrogen storage tank 10 (inner tank 11) has been cooled to an extremely low temperature state where it can store liquid hydrogen. An on-off valve 21V that can adjust its opening and closing state or opening degree is provided in the main supply line 21.

[0022] The precooling line 22 is used in a state where the liquid hydrogen storage tank 10 (inner tank 11) has not been cooled to an extremely low temperature state where it can store liquid hydrogen. An on-off valve 22V that can adjust its opening and closing state or opening degree is provided in the precooling line 22.

[0023] For example, when the liquid hydrogen storage tank 10 (inner tank 11) is not in an extremely low temperature state, the liquid hydrogen storage tank 10 (inner tank 11) is precooled by the liquid hydrogen supplied through the precooling line 22, and then the liquid hydrogen supplied through the main supply line 21 is stored in the liquid hydrogen storage tank 10.

[0024] The reliquefaction device 30 recovers and liquefies the boil-off gas accumulated in the upper part of the liquid hydrogen storage tank 10, and returns the liquefied liquid hydrogen of the boil-off gas to the liquid hydrogen storage tank 10 (inner tank 11).

[0025] The BOG recovery line 40 connects the liquid hydrogen storage tank 10 (inner tank 11) and the reliquefaction device 30, and is used to recover the boil-off gas accumulated in the upper part of the inner tank 11 into the liquid hydrogen storage tank 10.

[0026] One end of the BOG recovery line 40 is connected to the liquid hydrogen storage tank 10 (inner tank 11), and the other end branches off to BOG recovery lines 41 and 42. The ends of the BOG recovery lines 41 and 42 are connected to the reliquefaction device 30.

[0027] Between one end of the BOG recovery line 40 and the branching point, an on-off valve 40V is provided, which allows adjustment of the opening state and degree of opening between them.

[0028] The BOG recovery line 42 is equipped with an on / off valve 42V whose open / closed state and opening degree can be adjusted. This allows switching between recovering boil-off gas to the re-liquefaction unit 30 using only the BOG recovery line 41, and recovering boil-off gas to the re-liquefaction unit 30 using both the BOG recovery lines 41 and 42.

[0029] The liquid hydrogen supply line 50 connects the reliquefaction unit 30 and the liquid hydrogen storage tank 10 (inner tank 11), and is used to supply liquid hydrogen, which is produced when boil-off gas is reliquefied in the reliquefaction unit 30, to the liquid hydrogen storage tank 10 (inner tank 11).

[0030] The liquid hydrogen supply line 50 is equipped with an on / off valve 50V whose open / closed state and opening degree can be adjusted.

[0031] Thus, in this example, the liquid hydrogen storage system 100 can use the reliquefaction device 30 to reliquefy the boil-off gas from the liquid hydrogen storage tank 10 (inner tank 11) and return it to the liquid hydrogen storage tank 10 as liquid hydrogen. Therefore, for example, opportunities for the release of boil-off gas into the atmosphere in response to the pressure rise inside the liquid hydrogen storage tank 10 (inner tank 11) can be suppressed, and as a result, energy loss can be reduced.

[0032] [Reliquefaction equipment] Next, the reliquefaction apparatus 30 will be described with reference to Figures 2 and 3.

[0033] <Example 1> Figure 2 is a schematic diagram showing a first example of the configuration of the reliquefaction device 30.

[0034] As shown in Figure 2, the reliquefaction device 30 includes a liquefaction circulation circuit 31, a BOG recovery path 32, and a liquid hydrogen supply path 33.

[0035] The liquefaction circulation circuit 31 liquefies the boil-off gas recovered from the liquid hydrogen storage tank 10 through the BOG recovery line 40. Most of the liquefaction circulation circuit 31 (excluding the compressor CP) is covered by a cold box CB with an insulating structure.

[0036] The liquefaction circulation circuit 31 includes a low-pressure path L1, a compressor CP, a high-pressure path L2, a heat exchanger HX, a turbine bypass path L3, expansion turbines EP1 and EP2, an ortho-para converter OTC, a bypass path L4, a Joule-Thomson valve JT, and a storage tank ST.

[0037] The low-pressure path L1 is a path for sending hydrogen gas, including cryogenic boil-off gas recovered from the liquid hydrogen storage tank 10, to the compressor CP. The hydrogen gas in the low-pressure path L1 is always at a lower temperature than the hydrogen gas in the high-pressure path L2. One end of the low-pressure path L1 is connected to the storage tank ST, and the other end is connected to the suction side of the compressor CP.

[0038] The compressor CP compresses the hydrogen gas drawn in from the low-pressure path L1 and discharges the compressed hydrogen gas into the high-pressure path L2.

[0039] The high-pressure path L2 is the path through which hydrogen gas discharged from the compressor CP flows. The hydrogen gas in the high-pressure path L2 is always at a higher temperature than the hydrogen gas in the low-pressure path L1. One end of the high-pressure path L2 is connected to the discharge side of the compressor CP, and the other end is connected to the storage tank ST.

[0040] The heat exchanger HX performs heat exchange between the hydrogen gas in the low-pressure path L1 and the hydrogen gas in the high-pressure path L2. This allows the temperature of the hydrogen gas in the high-pressure path L2 to be lowered, while simultaneously restoring the temperature of the hydrogen gas in the low-pressure path L1 to a temperature range that the compressor CP can draw in.

[0041] The heat exchanger HX includes multiple stages of heat exchangers. The number of heat exchangers inside the cold box CB can be arbitrarily selected by the optimal design for each reliquefaction unit 30. For example, as shown in Figure 2, the heat exchanger HX includes heat exchangers HX1 to HX6.

[0042] For example, the low-pressure path L1 passes through the following heat exchangers in the order of HX6, HX5, HX4, HX3, HX2, and HX1, from upstream (storage tank ST side) to downstream (compressor CP side).

[0043] For example, the high-pressure path L2 passes through heat exchangers HX1, HX2, HX3, HX4, HX5, and HX6 in that order, from upstream (compressor CP side) to downstream (storage tank ST side).

[0044] For example, the temperature of the hydrogen gas compressed by the compressor CP is reduced to approximately 80 K (Kelvin) by heat exchanger HX1. Then, the temperature of the hydrogen gas is further reduced sequentially by heat exchangers HX2 to HX6, and the hydrogen gas, whose temperature has been reduced to approximately 21 K (Kelvin), flows out into the high-pressure path L2 downstream of heat exchanger HX (heat exchanger HX6).

[0045] The turbine bypass route L3 branches off hydrogen gas from the high-pressure route L2 between heat exchangers HX2 and HX3, and merges with the low-pressure route L1 between heat exchangers HX5 and HX6. The turbine bypass route L3 passes through heat exchanger HX4.

[0046] The expansion turbine EP1 is located upstream of the heat exchanger HX4 in the turbine bypass path L3. The expansion turbine EP1 expands the hydrogen gas in the turbine bypass path L3, causing the pressure and temperature of the hydrogen gas to flow downstream. As a result, the heat exchanger HX (heat exchanger HX4) can utilize the hydrogen gas in the turbine bypass path L3 as a coolant on the low-temperature side. Therefore, the temperature of the hydrogen gas in the high-pressure path L2 can be lowered more reliably.

[0047] The expansion turbine EP2 is located downstream of the heat exchanger HX4 in the turbine bypass path L3. The expansion turbine EP2 expands the hydrogen gas in the turbine bypass path L3, causing the pressure and temperature of the hydrogen gas to decrease and flow downstream. As a result, the hydrogen gas whose temperature has been lowered by the expansion turbine EP2 is recirculated into the low-pressure path L1 and can be used as a refrigerant on the low-temperature side of the heat exchangers HX (heat exchangers HX1 to HX5) for cold cooling. Therefore, the required amount of cold cooling can be reliably achieved on the low-temperature side (low-pressure path L1) of the heat exchangers HX (heat exchangers HX1 to HX6).

[0048] In the turbine bypass path L3, an on / off valve L3V is provided upstream of the expansion turbine EP1, which can adjust the presence or absence of hydrogen gas bypass and the amount of bypass.

[0049] The ortho-para converter OTC is located downstream of the heat exchanger HX (heat exchanger HX6) in the high-pressure path L2 and is used to convert (convert) ortho-hydrogen contained in the hydrogen gas cooled by the heat exchanger HX (heat exchanger HX1~HX6) to para-hydrogen. The ortho-para converter OTC incorporates a catalyst that promotes the conversion from ortho-hydrogen to para-hydrogen. The catalyst is formed from, for example, an iron-based or chromium-based paramagnetic material. This makes it possible to bring the ratio of ortho-hydrogen to para-hydrogen in the very low-temperature hydrogen gas cooled by the heat exchanger HX closer to equilibrium. Therefore, the amount of liquid hydrogen gasified in the storage tank ST and the liquid hydrogen storage tank 10, which is generated along with the conversion heat during ortho-para conversion, can be reduced, and energy loss can be suppressed.

[0050] Bypass path L4 is a path that recirculates the hydrogen gas in the ortho-para converter OTC to the low-pressure path L1. One end of bypass path L4 is connected to the ortho-para converter OTC, and the other end is connected to the upstream side of the heat exchanger HX (heat exchanger HX6) in the low-pressure path L1. This allows the ratio of ortho-hydrogen to para-hydrogen in the hydrogen gas of the low-pressure path L1 to approach equilibrium.

[0051] The Joule-Thomson valve JT is located downstream of the ortho-para converter OTC in the high-pressure path L2, and causes isenthalpy expansion (adiabatic expansion) of the hydrogen gas supplied from the ortho-para converter OTC. The heat exchanger HX is configured so that the temperature of the hydrogen gas supplied to the Joule-Thomson valve JT is below the inversion temperature. As a result, the isenthalpy expansion in the Joule-Thomson valve JT causes a temperature drop, which liquefies at least a portion of the hydrogen gas, and this liquefied portion can be returned to the storage tank ST as re-liquefied liquid hydrogen.

[0052] Liquid hydrogen is stored in storage tank ST. In addition, equilibrium hydrogen gas accumulates in the upper part of storage tank ST.

[0053] The BOG recovery path 32 is used to recover hydrogen gas (boil-off gas) recovered from the outside into the liquefaction circulation circuit 31.

[0054] BOG recovery route 32 includes BOG recovery routes 32A and 32B.

[0055] The BOG recovery path 32A is used to recover boil-off gas recovered through the BOG recovery lines 40 and 41 into the liquefaction circulation circuit 31. One end of the BOG recovery path 32A is connected to the BOG recovery line 41, and the other end is connected to the upstream side of the heat exchanger HX (heat exchanger HX6) in the low-pressure path L1. This allows the boil-off gas recovered from the liquid hydrogen storage tank 10 to be recovered into the low-pressure path L1.

[0056] Furthermore, depending on the temperature of the boil-off gas supplied (recovered) from the liquid hydrogen storage tank 10, the BOG recovery path 32A may be connected to the upstream side of some of the heat exchangers HX1 to HX6, rather than the upstream side of the heat exchangers HX1 to HX6. In addition, the BOG recovery path 32A may be configured to allow changes in the location where the boil-off gas is recovered in the low-pressure path L1, in accordance with changes in the temperature conditions of the boil-off gas supplied (recovered) from the liquid hydrogen storage tank 10, in relation to the heat exchangers HX1 to HX6.

[0057] The BOG recovery path 32B is used to recover boil-off gas recovered through the BOG recovery lines 40 and 42 into the liquefaction circulation circuit 31. One end of the BOG recovery path 32B is connected to the BOG recovery line 42, and the other end is connected to the downstream side of the heat exchanger HX (heat exchanger HX1) in the low-pressure path L1. This allows the boil-off gas recovered from the liquid hydrogen storage tank 10 to be recovered into the low-pressure path L1.

[0058] Furthermore, the BOG recovery path 32B passes through the heat exchanger HX1. This allows the heat exchanger HX (heat exchanger HX1) to utilize the cryogenic boil-off gas recovered from the liquid hydrogen storage tank 10 as a refrigerant on the low-temperature side. Therefore, the temperature of the hydrogen gas in the high-pressure path L2 can be reliably reduced without introducing an external auxiliary refrigerant such as liquid nitrogen, which is commonly used. In addition, by passing through the heat exchanger HX1, the temperature of the boil-off gas can be increased and restored to a temperature range that can be drawn into the compressor CP. Therefore, for example, it becomes unnecessary to introduce ambient temperature hydrogen gas from an external source to the suction side of the compressor CP.

[0059] The BOG recovery path 32B is provided with an on / off valve 32BV that can adjust the open / closed state and degree of opening of the BOG recovery path 32B.

[0060] Furthermore, other auxiliary refrigerants, such as liquid nitrogen, may be introduced into the heat exchanger HX1.

[0061] The liquid hydrogen supply path 33 is used to supply liquid hydrogen from the storage tank ST to the outside. One end of the liquid hydrogen supply path 33 is connected to the storage tank ST, and the other end is connected to the liquid hydrogen supply line 50. This allows the liquid hydrogen, which has been reliquefied by the boil-off gas in the liquefaction circulation circuit 31, to be returned to the liquid hydrogen storage tank 10.

[0062] In this way, the reliquefaction unit 30 can utilize cryogenic boil-off gas recovered from the outside as an auxiliary refrigerant for the heat exchanger HX1. This makes it possible to reduce or eliminate the use of dedicated auxiliary refrigerants such as liquid nitrogen. As a result, the energy required to generate dedicated auxiliary refrigerants can be reduced, and energy consumption during the reliquefaction of boil-off gas can be reduced.

[0063] <Example 2> Figure 3 is a schematic diagram showing a second example of the configuration of the reliquefaction device 30.

[0064] In the following, components identical to or corresponding to the first example described above will be denoted by the same reference numerals, and the explanation will focus on the parts that differ from the first example described above.

[0065] As shown in Figure 3, the reliquefaction device 30 includes a liquefaction circulation circuit 31, a BOG recovery path 32, and a liquid hydrogen supply path 33, similar to the first example described above.

[0066] The liquefaction circulation circuit 31 includes, as in the first example described above, a low-pressure path L1, a compressor CP, a high-pressure path L2, a heat exchanger HX, a turbine bypass path L3, expansion turbines EP1 and EP2, an ortho-para converter OTC, a bypass path L4, a Joule-Thomson valve JT, and a storage tank ST. However, unlike the first example described above, the liquefaction circulation circuit 31 also includes a supercritical expansion turbine SC.

[0067] Unlike the first example described above, the heat exchanger HX includes heat exchangers HX1 to HX6, as well as heat exchanger HX7.

[0068] The low-pressure path L1 passes through the following heat exchangers in the order of HX7, HX6, HX5, HX4, HX3, HX2, and HX1, from upstream (storage tank ST side) to downstream (compressor CP side).

[0069] The high-pressure path L2 passes through the following heat exchangers in the order of HX1, HX2, HX3, HX4, HX5, HX6, and HX7, from upstream (compressor CP side) to downstream (storage tank ST side).

[0070] The supercritical expansion turbine SC is installed between heat exchangers HX6 and HX7 in the high-pressure path L2. It further reduces the temperature of the hydrogen gas that has passed through heat exchanger HX6 by adiabatic expansion and supplies it to heat exchanger HX7.

[0071] Thus, in this example, the reliquefaction unit 30 can further cool the hydrogen gas in the high-pressure path L2 using a supercritical expansion turbine SC. Therefore, the liquefaction efficiency of the hydrogen gas (boil-off gas) can be improved.

[0072] [Application examples of liquid hydrogen storage systems] Next, with reference to Figure 4, an example of the application of the liquid hydrogen storage system 100 will be described.

[0073] Figure 4 shows an example of the application of the liquid hydrogen storage system 100. Specifically, Figure 4 shows an example of the hydrogen gas filling system 1.

[0074] As shown in Figure 4, the hydrogen gas filling system 1 includes a liquid hydrogen storage system 100, a liquid hydrogen vaporization equipment 200, a hydrogen gas compression equipment 300, a high-pressure hydrogen gas storage equipment 400, and a dispenser 500.

[0075] The liquid hydrogen storage system 100 receives liquid hydrogen delivered by a tanker truck RL, and stores it in a liquid hydrogen storage tank 10 via a liquid hydrogen supply line 20.

[0076] The liquid hydrogen vaporization equipment 200 is, for example, centered around a rectification column, and generates hydrogen gas by vaporizing liquid hydrogen supplied from the liquid hydrogen storage tank 10.

[0077] The hydrogen gas compression equipment 300 compresses the hydrogen gas supplied from the liquid hydrogen vaporization equipment 200.

[0078] The hydrogen gas compression equipment 300 includes a low-pressure hydrogen gas storage tank 310 and a compressor 320.

[0079] The low-pressure hydrogen gas storage tank 310 stores hydrogen gas at a relatively low pressure, supplied from the liquid hydrogen vaporization equipment 200.

[0080] The compressor 320 compresses the hydrogen gas supplied from the low-pressure hydrogen gas storage tank 310, producing hydrogen gas that has been pressurized to a relatively high pressure.

[0081] The high-pressure hydrogen gas generated in the hydrogen gas compression equipment 300 (compressor 320) is supplied to at least one of the high-pressure hydrogen gas storage equipment 400 and the dispenser 500.

[0082] The high-pressure hydrogen gas storage facility 400 stores high-pressure hydrogen gas supplied from the hydrogen gas compression facility 300 and also supplies high-pressure hydrogen gas to the dispenser 500. For example, the high-pressure hydrogen gas storage facility 400 includes multiple hydrogen gas storage tanks that have very high pressure resistance and are capable of storing high-pressure hydrogen gas.

[0083] The dispenser 500 fills the hydrogen tank TNK of the vehicle VCL with high-pressure hydrogen gas supplied from at least one of the hydrogen gas compression equipment 300 and the high-pressure hydrogen gas storage equipment 400. The vehicle VCL is, for example, a fuel cell vehicle equipped with a fuel cell capable of generating electricity using hydrogen gas as fuel.

[0084] The Dispenser 500 includes the Precooler 510.

[0085] The precooler 510 cools the high-pressure hydrogen gas supplied from at least one of the hydrogen gas compression equipment 300 and the high-pressure hydrogen gas storage equipment 400 before filling the hydrogen tank TNK. This prevents the temperature of the hydrogen tank TNK from exceeding a predetermined reference temperature (e.g., 85°C) due to the rise in temperature of the hydrogen gas being filled into the hydrogen tank under pressurization.

[0086] The precooler 510 includes a cooling unit 511 and a refrigerator 512.

[0087] The cooling unit 511 cools the high-pressure hydrogen gas supplied from at least one of the hydrogen gas compression equipment 300 and the high-pressure hydrogen gas storage equipment 400.

[0088] The refrigerator 512 supplies cold energy to the cooling unit 511 to cool the hydrogen gas.

[0089] Alternatively, a bypass route may be provided to direct the hydrogen gas from the liquid hydrogen vaporization equipment 200 to the dispenser 500, so that the hydrogen gas from the liquid hydrogen vaporization equipment 200 is directly mixed with the hydrogen gas that is filled from the dispenser 500 into the hydrogen tank TNK. This allows the temperature of the hydrogen gas being filled from the dispenser 500 into the hydrogen tank TNK to be lowered by the cryogenic hydrogen gas from the liquid hydrogen vaporization equipment 200. In this case, the precooler 510 may be omitted.

[0090] In this way, the liquid hydrogen storage system 100 can be applied to the hydrogen gas filling system 1.

[0091] Furthermore, the liquid hydrogen storage system 100 may be applied to systems and equipment other than the hydrogen gas filling system 1. For example, the liquid hydrogen storage system 100 may be applied to a liquid hydrogen transfer system for transferring liquid hydrogen to and from other liquid hydrogen storage tanks. Other liquid hydrogen storage tanks are, for example, liquid hydrogen storage tanks installed in the same liquid hydrogen storage facility. Alternatively, other liquid hydrogen storage tanks may be liquid hydrogen storage tanks mounted on ships docked in ports adjacent to the land-based facility where the liquid hydrogen storage system 100 is installed.

[0092] [Effect] Next, the operation of the liquefaction apparatus according to this embodiment will be described.

[0093] In this embodiment, the liquefaction device comprises a first path, a compression section, a second path, a multi-stage heat exchange section, a liquefaction section, and a third path. The liquefaction device is, for example, the reliquefaction device 30 described above. The first path is, for example, the low-pressure path L1 described above. The compression section is, for example, the compressor CP described above. The second path is, for example, the high-pressure path L2 described above. The multi-stage heat exchange section is, for example, the heat exchangers HX (heat exchangers HX1 to HX6 or heat exchangers HX1 to HX7) described above. The liquefaction section is, for example, the Joule-Thomson valve JT described above. The third path is, for example, the BOG recovery path 32B. Specifically, the first path is through which boil-off gas supplied from a storage device that stores liquid hydrogen flows. The storage device is, for example, the liquid hydrogen storage tank 10 described above. The compression section compresses the boil-off gas in the first path. Furthermore, the second path is through which the high-temperature boil-off gas flowing out from the compression section passes. In addition, the multi-stage heat exchange section performs heat exchange between the low-temperature boil-off gas of the first path and the high-temperature boil-off gas of the second path. The liquefaction section liquefies at least a portion of the boil-off gas of the second path, whose temperature has decreased through the multi-stage heat exchange section, by expansion. The third path is provided separately from the first path and passes boil-off gas supplied from the storage device as a low-temperature refrigerant to the first heat exchange section, which is the highest-temperature of the multi-stage heat exchange section. The first heat exchange section is, for example, the heat exchanger HX1 described above.

[0094] This allows the liquefaction unit to utilize the cryogenic boil-off gas supplied from the storage unit as the refrigerant on the low-temperature side of the first heat exchange section. Therefore, for example, the amount of auxiliary refrigerant introduced from the outside can be reduced, or the introduction of auxiliary refrigerant from the outside can be stopped altogether. Thus, the liquefaction unit can reduce energy consumption during the re-liquefaction of the boil-off gas.

[0095] Furthermore, in this embodiment, the third path may be connected to the first path between the first heat exchange section and the compression section.

[0096] This allows the boil-off gas to recover its temperature to a range suitable for introduction into the compression section by passing through the first heat exchange section, thus enabling its introduction into the compression section. Therefore, for example, it becomes unnecessary to introduce hydrogen gas at room temperature from an external source.

[0097] Furthermore, in this embodiment, the liquefaction device may include a fourth path. The fourth path is, for example, the BOG recovery path 32A described above. Specifically, the fourth path allows boil-off gas supplied from the storage device upstream of at least some of the heat exchange sections among the multiple stages of heat exchange sections to flow into the first path.

[0098] As a result, the liquefaction device can recover boil-off gas recovered from the storage device upstream of the first path, in addition to the boil-off gas recovered downstream of the first path through the third path.

[0099] Furthermore, in this embodiment, the liquefaction system may include the liquefaction device described above and a storage device that supplies boil-off gas to the liquefaction device and receives the liquid hydrogen from the liquefaction device after the boil-off gas has been liquefied. The liquefaction system is, for example, the liquid hydrogen storage system 100 described above.

[0100] Furthermore, in this embodiment, the hydrogen gas filling system may include the liquefaction device, storage device, generation device, and filling device described above. The hydrogen gas filling system is, for example, the hydrogen gas filling system 1 described above. The generation device is, for example, the liquid hydrogen vaporization equipment 200 described above. The filling device is, for example, the dispenser 500 described above. Specifically, the storage device supplies boil-off gas to the liquefaction device and receives liquid hydrogen from the liquefaction device after the boil-off gas has been liquefied. The generation device generates hydrogen gas from the liquid hydrogen supplied from the storage device. The filling device then fills the object to be filled with the hydrogen gas generated by the generation device. The object to be filled is the hydrogen tank TNK of the vehicle VCL.

[0101] This allows liquefaction systems and hydrogen gas filling systems to use a liquefaction device to reliquefy the boil-off gas from the storage device and return the reliquefied liquid hydrogen to the storage device. Therefore, it is possible to suppress situations where the pressure in the storage device increases due to the boil-off gas and releases the boil-off gas into the atmosphere, thereby reducing energy loss.

[0102] Although embodiments have been described in detail above, this disclosure is not limited to these specific embodiments, and various modifications and changes are possible within the scope of the gist described in the claims. [Explanation of symbols]

[0103] 1. Hydrogen gas filling system 10 Liquid hydrogen storage tanks 11 Inner tank 12 Outer tank 20 Liquid hydrogen supply lines 21 Main supply line 21V Shut-off valve 22 Pre-cooling line 22V Shut-off valve 30 Reliquefaction equipment 31 Liquefaction circulation circuit 32 BOG Recovery Route 32A BOG Recovery Route 32B BOG Recovery Route 32BV Shut-off valve 33. Liquid hydrogen supply routes 40 BOG recovery line 40V shut-off valve 41 BOG Recovery Line 42 BOG recovery line 42V Shut-off valve 50 Liquid hydrogen supply lines 50V shut-off valve 100 Liquid Hydrogen Storage Systems 200 Liquid hydrogen vaporization equipment 300 Hydrogen gas compression equipment 310 Low-pressure hydrogen gas storage tank 320 Compressor 400 High-Pressure Hydrogen Gas Storage Facilities 500 Dispenser 510 Precooler 511 Cooling section 512 Refrigeration unit CB Cold Box CP compressor EP1, EP2 Expansion Turbine HX heat exchanger HX1~HX7 Heat exchanger JT Jules Thomson dialect L1 Low-voltage path L2 High-Voltage Path L3 Turbine Bypass Route L3V Shut-off Valve L4 Bypass Route OTC Ortho-Para Converter RL Laurie SC Supercritical Expansion Turbine ST storage tank TNK Hydrogen Tank VCL Vehicle

Claims

1. A first path through which boil-off gas supplied from a storage device for storing liquid hydrogen flows, A compression section for compressing the boil-off gas in the first path, A second path through which the high-temperature boil-off gas flowing out from the compression section passes, A multi-stage heat exchange section that performs heat exchange between the boil-off gas on the low-temperature side of the first path and the boil-off gas on the high-temperature side of the second path, A liquefaction unit that liquefies at least a portion of the boil-off gas in the second path, whose temperature has decreased through the aforementioned multi-stage heat exchange unit, by expansion, A third path is provided separately from the first path, and passes the boil-off gas supplied from the storage device as a low-temperature refrigerant to the first heat exchange section, which is the highest-temperature section among the multiple stages of heat exchange sections. Liquefaction equipment.

2. The third path is connected to the first path between the first heat exchange section and the compression section. The liquefaction apparatus according to claim 1.

3. A fourth path is provided that allows boil-off gas supplied from the storage device to flow into the first path upstream of at least some of the heat exchange sections among the multiple stages of heat exchange sections. The liquefaction apparatus according to claim 2.

4. A liquefaction apparatus according to any one of claims 1 to 3, The storage device comprises supplying boil-off gas to the liquefaction device and receiving liquid hydrogen from the liquefaction device after the boil-off gas has been liquefied. Liquefaction system.

5. A liquefaction apparatus according to any one of claims 1 to 3, A storage device that supplies boil-off gas to the liquefaction device and receives liquid hydrogen from the liquefaction device after the boil-off gas has been liquefied, A generator that generates hydrogen gas from liquid hydrogen supplied from the storage device, The device comprises a filling device that fills an object to be filled with hydrogen gas generated by the aforementioned generating device. Hydrogen gas filling system.

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