Cryogenic compression equipment and boil-off gas liquefaction system including same

Abstract

This cryogenic compression equipment comprises: a compressor including a suction port for sucking a cryogenic fluid, a compression unit for compressing the cryogenic fluid to be sucked, and a discharge port for discharging the compressed fluid; and a heating device for heating the compressed fluid discharged from the discharge port.

Description

Title of Invention: CRYOGENIC COMPRESSION EQUIPMENT AND BOIL-OFF GAS LIQUEFACTION SYSTEM INCLUDING SAME Technical Field

[0001] The present invention relates to cryogenic compression equipment for compressing a cryogenic fluid, and to a boil-off gas liquefaction system including the same. Background Art

[0002] In storage equipment including a tank for storing a cryogenic liquid, such as liquefied hydrogen, a compressor is provided for compressing gas. For example, Patent Literature (PTL) 1 discloses a compressor for compressing boil-off gas generated in the tank of the storage equipment. Citation List Patent Literature

[0003] PTL 1: Japanese Laid-Open Patent Application Publication No. 2023-177464 Summary of Invention Technical Problem

[0004] The compression efficiency of the compressor improves as the temperature of the drawn-in gas decreases. Conversely, if the temperature of the intake gas is too low, the compressed gas discharged from the compressor may have a temperature lower than ambient temperature. In such a case, low-temperature safeguards are required on the downstream side of the outlet of the compressor, leading to a disadvantageous increase in cost.

[0005] In view of this, an object of the present invention is to provide cryogenic compression equipment capable of improving compression efficiency and suppressing an increase in cost, and to provide a boil-off gas liquefaction system including the same. Solution to Problem

[0006] Cryogenic compression equipment according to the present invention includes: a compressor including an inlet through which a cryogenic fluid is drawn in, a compression part configured to compress the cryogenic fluid drawn in, and an outlet through which a compressed fluid is discharged; and a heating device configured to heat the compressed fluid discharged through the outlet.

[0007] According to the present invention, the cryogenic fluid is drawn in through the inlet of the compressor. Accordingly, the compression efficiency of the compressor can be improved. The heating device heats the compressed fluid discharged through the outlet of the compressor. Accordingly, the temperature of the compressed fluid can be increased. Consequently, the requirements for low-temperature safeguards to be implemented for the downstream side of the outlet can be mitigated, suppressing an increase in the cost of manufacturing the cryogenic compression equipment. Thus, with the cryogenic compression equipment, the compression efficiency can be improved, and an increase in cost can be suppressed.

[0008] A boil-off gas liquefaction system according to the present invention includes: the aforementioned cryogenic compression equipment; and a liquefier configured to liquefy the compressed fluid being discharged from the cryogenic compression equipment. The cryogenic compression equipment draws in boil-off gas that is a cryogenic fluid generated by vaporization of a cryogenic liquid within a liquid tank that stores the cryogenic liquid.

[0009] According to the present invention, the cryogenic compression equipment draws in the boil-off gas that is the cryogenic fluid generated by the vaporization of the cryogenic liquid within the liquid tank. Subsequently, the cryogenic compression equipment compresses and discharges the boil-off gas, and the liquefier liquefies the compressed boil-off gas discharged from the cryogenic compression equipment. This enables a boil-off gas liquefaction system capable of recycling the boil-off gas. Furthermore, as previously described, an increase in the cost of the cryogenic compression equipment can be suppressed, enabling a cost-effective boil-off gas liquefaction system. Advantageous Effects of Invention

[0010] According to the present invention, it is possible to improve compression efficiency and suppress an increase in cost.

[0011] The above object, other objects, features, and advantages of the present invention will be made clear by the following detailed explanation of preferred embodiments with reference to the attached drawings. Brief Description of Drawings

[0012] Fig. 1 is a circuit diagram illustrating a boil-off gas liquefaction system according to Embodiment 1. Fig. 2 is a schematic view illustrating cryogenic fluid compression equipment provided in the boil-off gas liquefaction system of Fig. 1. Description of Embodiments

[0013] Hereinafter, a boil-off gas liquefaction system (hereinafter referred to as “the BOG liquefaction system”) 1 according to an embodiment of the present disclosure and cryogenic fluid compression equipment (hereinafter referred to simply as “the compression equipment”) 11 provided in the BOG liquefaction system 1 will be described with reference to the aforementioned drawings. Note that the concept of directions mentioned in the following description is used for the sake of explanation; the orientations, etc., of elements according to the invention are not limited to these directions. Furthermore, each of the boil-off gas liquefaction system 1 and the compression equipment 11 provided therein, which will be described below, is merely an embodiment of the present invention. Thus, the present invention is not limited to the embodiment and may be subject to addition, deletion, and alteration within the scope of the essence of the present invention. [BOG Liquefaction System]

[0014] The BOG liquefaction system 1 is provided, for example, in liquefied gas storage equipment 2 such as a liquefied gas loading or unloading terminal or a liquefied gas transportation apparatus (for example, a tanker). The BOG liquefaction system 1 liquefies a cryogenic boil-off gas generated by the evaporation of liquefied gas, such as liquefied hydrogen or liquefied helium. In the present disclosure, “cryogenic” refers to a temperature equal to or less than a condensation temperature at which air liquefies. Note that a cryogenic temperature range may be less than or equal to the condensation temperature of oxygen, but is not limited to said temperature range. In the present embodiment, the liquefied gas is liquefied hydrogen.

[0015] The liquefied gas storage equipment 2 includes a liquefied hydrogen tank 3. The liquefied hydrogen tank 3, which is an example of the liquid tank, stores liquefied hydrogen. The liquefied gas storage equipment 2 loads loading / unloading equipment (not illustrated in the drawings) with the liquefied hydrogen stored in the liquefied hydrogen tank 3. For example, when the liquefied gas storage equipment 2 is a loading terminal, the liquefied hydrogen stored in the liquefied hydrogen tank 3 of the liquefied gas storage equipment 2 is transported to destination loading / unloading equipment, for example, a transportation apparatus, via a transfer pipe 4. When the liquefied gas storage equipment 2 is an unloading terminal, the liquefied hydrogen transferred from origin unloading / unloading equipment, e.g., a transportation apparatus, via the transfer pipe 4 is stored into the liquefied hydrogen tank 3 of the liquefied gas storage equipment 2. Furthermore, the boil-off gas is transferred via a BOG pipe 5 between the liquefied gas storage equipment 2 and the loading / unloading equipment in a direction opposite to the flow of the transferred liquefied hydrogen. The boil-off gas is gas generated by the evaporation of liquefied hydrogen within the liquefied gas storage equipment 2 and the loading / unloading equipment. In the liquefied gas storage equipment 2, the boil-off gas is generated primarily within the liquefied hydrogen tank 3. The BOG pipe 5 is connected to the liquefied hydrogen tank 3, and the boil-off gas is introduced from the liquefied hydrogen tank 3 into the BOG pipe 5. More specifically, a return gas pipe 6 is connected to the BOG pipe 5, and the boil-off gas is transferred via the BOG pipe 5 and the return gas pipe 6. Note that the return gas pipe 6 does not necessarily need to be connected to the BOG pipe 5 and may instead be directly connected to the liquefied hydrogen tank 3. The boil-off gas is generated not only within the liquefied hydrogen tank 3, but also within any portion of the liquefied gas storage equipment 2 that stores or conveys the liquefied gas (for example, within the transfer pipe 4). The BOG liquefaction system 1 produces liquefied hydrogen by liquefying said boil-off gas. In other words, the BOG liquefaction system 1 recovers the boil-off gas in the form of liquefied hydrogen. For example, the BOG liquefaction system 1 returns the produced liquefied hydrogen to the liquefied hydrogen tank 3. The BOG liquefaction system 1 configured in this manner includes the compression equipment 11, a boil-off gas tank 12, and a liquefier 13. [Compression Equipment]

[0016] The compression equipment 11, which is an example of the cryogenic fluid compression equipment, compresses cryogenic boil-off gas. Furthermore, the compression equipment 11 heats the compressed boil-off gas. The compression equipment 11 includes a compressor 21 and a heating device 22, which are also illustrated in Fig. 2. More specifically, the compression equipment 11 further includes an inlet pipe 23, an outlet pipe 24, and a downstream pipe 25.

[0017] The inlet pipe 23 is connected to the BOG pipe 5. The BOG pipe 5 has a vacuum- insulated structure. In the present embodiment, the BOG pipe 5 is a vacuum double-wall pipe and is configured to maintain the boil-off gas flowing therein at the cryogenic temperature. Furthermore, the return gas pipe 6 and the inlet pipe 23 are connected to the BOG pipe 5 as separate branches extending therefrom. The inlet pipe 23 also has a vacuum-insulated structure. More specifically, the inlet pipe 23 is likewise configured as a vacuum double-wall pipe. This allows the inlet pipe 23 to also maintain the boil-off gas flowing therein at the cryogenic temperature.

[0018] The compressor 21 compresses the cryogenic boil-off gas to produce compressed gas. During this process, the compression causes the temperature of the boil-off gas to rise. More specifically, the temperature of the compressed gas increases from the cryogenic temperature to a low temperature as a result of the compression by the compressor 21. The low temperature is, for example, between -100°C and -20°C, inclusive. In the present embodiment, the compressed gas has a temperature in a range of -90°C to -70°C. In the present embodiment, the compressor 21 is a volumetric compressor configured to handle boil-off gas from liquefied hydrogen (LH2). However, the compressor 21 is not limited to a volumetric compressor and may alternatively be a centrifugal compressor. The compressor 21 includes an inlet 21a, a compression part 21b, and an outlet 21c. Note that at least the compression part 21b of the compressor 21 is vacuum-insulated. In the present embodiment, the inlet 21a and the compression part 21b of the compressor 21 are vacuum-insulated. Accordingly, the compressor 21 can withstand handling the cryogenic boil-off gas. The compressor 21 is capable of compressing the cryogenic boil-off gas while suppressing the liquefaction of air contained in the surrounding atmosphere.

[0019] The cryogenic boil-off gas is drawn in through the inlet 21a. More specifically, the inlet 21a is connected to the inlet pipe 23. The inlet 21a is connected to the inlet pipe 23, for example, via a bayonet fitting. Furthermore, the inlet 21a is connected to the BOG pipe 5 via the inlet pipe 23, and is further connected to the liquefied hydrogen tank 3 via the BOG pipe 5. The boil-off gas generated within the liquefied hydrogen tank 3 is routed to the inlet 21a via the BOG pipe 5 and the inlet pipe 23.

[0020] The compression part 21b compresses the drawn-in cryogenic boil-off gas. The compression part 21b, which is connected to the inlet pipe 23 via the inlet 21a, draws in the cryogenic boil-off gas flowing through the inlet pipe 23. The compressor 21 is a volumetric compressor as previously described, and the compression part 21b includes, for example, a cylinder 31, a piston 32, and a drive source 33. The cylinder 31 has, for example, a vacuum-insulated structure, and introduces the drawn-in cryogenic boil-off gas into a bore 31a formed therein. The piston 32 is received within the bore 31a of the cylinder 31 to permit reciprocal movement therein. The drive source 33 is, for example, an electric motor, and reciprocates the piston 32. By reciprocating the piston 32 via the drive source 33, the compression part 21b compresses the cryogenic boil-off gas introduced into the bore 31a.  This compression causes the temperature of the boil-off gas to rise. In the present embodiment, the temperature of the boil-off gas increases from the cryogenic temperature to the low temperature.

[0021] The compressed gas (specifically, the compressed boil-off gas), which is an example of the compressed fluid, is discharged through the outlet 21c. More specifically, the outlet 21c is connected to the outlet pipe 24, which will be described in detail later. In the present embodiment, the outlet 21c is connected to the outlet pipe 24, for example, via a flanged joint. Note that the method for connecting the outlet 21c and the outlet pipe 24 is not limited to a flanged joint and may be other joints such as a bayonet fitting. The boil-off gas compressed by the compression part 21b is discharged to the outlet pipe 24 through the outlet 21c.

[0022] The outlet pipe 24 is connected to the outlet 21c. In the present embodiment, the outlet pipe 24 has a thermally insulated structure with thermal insulation material. The outlet pipe 24 includes a pipe section 24a and a cover member 24b. The pipe section 24a is connected to the outlet 21c. In the present embodiment, the pipe section 24a is connected to the outlet 21c, for example, via a flanged joint. The low-temperature compressed gas discharged through the outlet 21c flows through the pipe section 24a. The cover member 24b is thermally insulating and covers the pipe section 24a. More specifically, the cover member 24b covers the entire circumference of the pipe section 24a. The cover member 24b is formed of, for example, a thermally insulating foam resin. In the present embodiment, the cover member 24b is formed of polyurethane foam (PUF). However, the material of the cover member 24b is not limited to PUF, provided that the cover member 24b is thermally insulating. Note that the thermal insulation performance of the cover member 24b is lower than that of the vacuum double-wall pipe. In other words, thermal input to the boil-off gas flowing through the interior of the pipe section 24a is greater through the cover member 24b than through the vacuum double-wall pipe.

[0023] The heating device 22 heats the compressed gas discharged through the outlet 21c. In the present embodiment, the heating device 22 is disposed on the outlet pipe 24. The heating device 22 heats the low-temperature compressed gas flowing thereto from the outlet pipe 24. More specifically, the heating device 22 heats the low-temperature compressed gas to a temperature within a service temperature limit range for the downstream pipe 25, which will be described in detail later. In the present embodiment, the heating device 22 heats the boil-off gas to a temperature equal to or close to ambient temperature. The ambient temperature is, for example, in a range of 5°C to 35°C. Note that the ambient temperature is exemplary and is not limited to this range.

[0024] The heating device 22 is a heat exchanger through which a heat medium flows. Specifically, the heating device 22 causes the compressed gas and the heat medium (for example, water) to exchange heat therebetween. Consequently, the boil-off gas is heated. Meanwhile, the heat medium is cooled, and the cooled heat medium is recycled for use in a cooler and the like. However, the heat medium does not necessarily need to be recycled, and the heat may alternatively be released to the atmosphere. The heating device 22 is not limited to a heat exchanger and may alternatively be an electric heating coil, a heater, or the like. In this case, the heating device 22 may be disposed on the exterior of the pipe section 24a of the outlet pipe 24, or may be embedded within the cover member 24b, for example.

[0025] The downstream pipe 25 is connected to the downstream part of the outlet pipe 24. In the present embodiment, the downstream pipe 25 is connected to the downstream part of the outlet pipe 24 via the heating device 22. Note that when the heating device 22 is disposed on the outer peripheral surface of the outlet pipe 24 in a manner such as an electric heating coil, a heater, or the like, the downstream pipe 25 may be directly connected to the outlet pipe 24. The downstream pipe 25 is a pipe featuring a service temperature limit range higher than the low temperature. The service temperature limit range for the downstream pipe 25 includes ambient temperature. Accordingly, the requirements for low-temperature safeguards for the downstream pipe 25 can be mitigated, allowing the downstream pipe 25 to be manufactured at low cost. For example, restrictions on the lower service temperature limit for the material of the downstream pipe 25, which are exemplary low-temperature safeguards, are mitigated. This improves the design flexibility of the downstream pipe 25, enabling the use of a low-cost material for the downstream pipe 25. In the present embodiment, the downstream pipe 25 is a carbon steel pipe. Carbon steel is a relatively cost-effective material and can be used as the material of a pipe through which hydrogen flows. The service temperature limit range for carbon steel is between -10°C and 350°C, inclusive. However, the service temperature limit range for carbon steel is not limited to this range. The compressed gas heated by the heating device 22, which is ambient-temperature compressed gas in the present embodiment, flows through the downstream pipe 25. [Boil-off Gas Tank]

[0026] As illustrated in Fig. 1, the boil-off gas tank 12 stores the ambient-temperature compressed gas. More specifically, the boil-off gas tank 12 is connected to the downstream pipe 25. In the present embodiment, the boil-off gas tank 12 is connected to the downstream pipe 25 in parallel with the liquefier 13, which will be described in detail later. Note that the boil-off gas tank 12 may be interposed on the downstream pipe 25 and connected in series with the liquefier 13. The boil-off gas tank 12 temporarily stores the boil-off gas flowing through the downstream pipe 25. [Liquefier]

[0027] The liquefier 13 liquefies the compressed gas discharged from the compression equipment 11. Note that in the present embodiment, the compressed gas liquefied by the liquefier 13 includes not only the compressed gas directly supplied from the compression equipment 11, but also the compressed gas discharged from the compression equipment 11 and stored in the boil-off gas tank 12. The liquefier 13 is connected to the downstream pipe 25. In the present embodiment, the liquefier 13 is connected to the downstream pipe 25 in parallel with the boil-off gas tank 12. Accordingly, the compressed gas can be supplied to the liquefier 13 directly from the compression equipment 11 or from the boil-off gas tank 12. The liquefier 13 liquefies the compressed gas supplied thereto. Specifically, the liquefier 13 cools the compressed gas, thereby producing liquefied hydrogen. The liquefier 13 is connected to a recovery pipe 14 and is connected to the liquefied hydrogen tank 3 via the recovery pipe 14. The recovery pipe 14 has a vacuum-insulated structure. In the present embodiment, the recovery pipe 14 is configured as a vacuum double-wall pipe. The liquefier 13 returns the liquefied hydrogen to the liquefied hydrogen tank 3 via the recovery pipe 14 having the vacuum-insulated structure. Thus, the boil-off gas is recovered. [Operation of BOG Liquefaction System and Compression Equipment]

[0028] In the liquefied hydrogen tank 3, cryogenic boil-off gas is generated, and the generated boil-off gas is drained from the liquefied hydrogen tank 3 to the BOG pipe 5. The BOG pipe 5 is configured such that the boil-off gas flows primarily to the BOG liquefaction system 1 during periods other than a loading / unloading operation, and the boil-off gas is recovered within the BOG liquefaction system 1. In the BOG liquefaction system 1, the boil-off gas generated within the liquefied hydrogen tank 3 is recovered as follows. Specifically, the boil-off gas in the BOG pipe 5 is supplied to the inlet pipe 23 and is drawn into the inlet 21a of the compressor 21 via the inlet pipe 23. At this time, the boil-off gas can be maintained at the cryogenic temperature by the BOG pipe 5 and the inlet pipe 23, each of which has a vacuum-insulated structure, and when introduced into the inlet 21a of the compressor 21, remain in the cryogenic temperature state.

[0029] In the compressor 21, the compression part 21b compresses the cryogenic boil-off gas drawn in through the inlet 21a. Specifically, in the compressor 21, the drive source 33 drives the piston 32 to reciprocate such that the cryogenic boil-off gas is drawn into the bore 31a of the cylinder 31 through the inlet 21a and compressed. At the time of compression, the cryogenic boil-off gas is heated to the low temperature. Subsequently, the low-temperature compressed gas is discharged to the outlet pipe 24 through the outlet 21c. The outlet pipe 24 is thermally insulating and suppresses the surroundings of the outlet pipe 24 from freezing due to the low-temperature compressed gas flowing therein. Meanwhile, the low-temperature compressed gas is introduced into the heating device 22 via the outlet pipe 24.

[0030] In the heating device 22, the low-temperature compressed gas is heated. More specifically, the heating device 22 causes the low-temperature compressed gas and the heat medium to exchange heat therebetween. Consequently, the boil-off gas is brought to a temperature equal to or close to ambient temperature prior to flowing into the downstream pipe 25. In the downstream pipe 25, the compressed gas is stored in the boil-off gas tank 12 or is transferred to the liquefier 13. In the liquefier 13, the boil-off gas is recovered in the form of liquefied hydrogen. Subsequently, the liquefied hydrogen is returned to the liquefied hydrogen tank 3.

[0031] The cryogenic boil-off gas is drawn into the compression equipment 11 according to the present embodiment through the inlet 21a of the compressor 21. Accordingly, the compression efficiency of the compressor 21 can be improved. The heating device 22 heats the compressed gas discharged through the outlet 21c of the compressor 21. Accordingly, the temperature of the compressed gas can be increased. Consequently, the requirements for low-temperature safeguards to be implemented for the downstream side of the outlet 21c can be mitigated, suppressing an increase in the cost of manufacturing the compression equipment 11. Thus, with the compression equipment 11, the compression efficiency can be improved, and an increase in cost can be suppressed.

[0032] Furthermore, in the compression equipment 11 according to the present embodiment, the inlet pipe 23 is a vacuum-insulated double-wall pipe. This allows the boil-off gas to remain in the cryogenic temperature state, which features a reduced temperature, when drawn into the compressor 21. Consequently, the compression efficiency of the compressor 21 can be improved.

[0033] Furthermore, in the compression equipment 11 according to the present embodiment, the heating device 22 is disposed on the outlet pipe 24. Accordingly, the layout flexibility of the heating device 22 can be enhanced.

[0034] Furthermore, in the compression equipment 11 according to the present embodiment, the outlet pipe 24 includes the pipe section 24a and the cover member 24b. Accordingly, costs related to the low-temperature safeguards can be reduced.

[0035] Furthermore, in the compression equipment 11 according to the present embodiment, the heating device 22 heats the compressed gas to a temperature within the service temperature limit range for the downstream pipe 25 that includes ambient temperature. Accordingly, the requirements for low-temperature safeguards can be mitigated. Thus, an increase in the cost of the compression equipment 11 can be further suppressed.

[0036] Furthermore, in the compression equipment 11 according to the present embodiment, the downstream pipe 25 is formed of carbon steel. This reduces the cost of the downstream pipe 25. Thus, an increase in the cost of the compression equipment 11 can be further suppressed.

[0037] Furthermore, in the compression equipment 11 according to the present embodiment, the heating device 22 is a heat exchanger through which the heat medium flows, and causes the heat medium and the compressed gas to exchange heat therebetween. Accordingly, the heating device 22 allows the heat medium to absorb cold energy from the compressed gas. This enables the cold energy to be recycled via the heat medium.

[0038] In the BOG liquefaction system 1 according to the present embodiment, the compression equipment 11 draws in the cryogenic boil-off gas generated by the vaporization of the liquefied hydrogen within the liquefied hydrogen tank 3. Subsequently, the compression equipment 11 compresses and discharges the boil-off gas, and the liquefier 13 liquefies the compressed gas discharged from the compression equipment 11. This enables the BOG liquefaction system 1 capable of recycling the boil-off gas. Furthermore, as previously described, an increase in the cost of the compression equipment 11 can be suppressed, enabling the cost-effective BOG liquefaction system 1. <Other Embodiments>

[0039] While the boil-off gas is exemplified as the cryogenic fluid in the BOG liquefaction system 1 according to the present embodiment, other types of cryogenic gas may be utilized. Furthermore, the cryogenic fluid may be a mixture of liquid and gas, for example, a mixture of liquefied hydrogen and boil-off gas. While the inlet pipe 23 and the inlet 21a of the compressor 21 are connected via a bayonet fitting in the compression equipment 11 according to the present embodiment, these may be connected via a flanged joint; the method for connecting the inlet pipe 23 and the inlet 21a is not limited. The inlet pipe 23 does not necessarily need to be configured as a vacuum double-wall pipe entirely up to an end thereof on the inlet 21a side, and a portion of the inlet pipe 23 at and around the end thereof on the inlet 21a side may be configured as a single-wall pipe.

[0040] While the compressed gas has a temperature increased to the low temperature through the compression by the compressor 21 in the compression equipment 11 according to the present embodiment, the compressed gas does not necessarily need to have a temperature increased to the low temperature. In this case, it is preferable that the outlet pipe 24 be also a vacuum double-wall pipe.  Note that the outlet pipe 24 does not necessarily need to be a vacuum double-wall pipe.  Furthermore, while the compression equipment 11 according to the present embodiment includes the boil-off gas tank 12, the compression equipment 11 does not necessarily need to include the boil-off gas tank 12.

[0041] The compression equipment 11 according to the present embodiment does not necessarily need to be provided in the BOG liquefaction system 1, provided that the compression equipment 11 is applied to equipment required to compress a cryogenic fluid. The compression equipment 11 does not necessarily need to transfer the compressed gas to the liquefier 13 and may alternatively supply the compressed gas to other equipment such as a power plant. Furthermore, the liquefied gas serving as the target fluid is not limited to liquefied hydrogen, and may alternatively be other types of liquefied gas, such as liquefied helium. Moreover, the heating device 22 may be embedded within the compressor 21 (for example, at a location proximate to the outlet 21c, the exit of the compression part 21b). <Exemplary Embodiments>

[0042] Cryogenic compression equipment according to the first aspect includes: a compressor including an inlet through which a cryogenic fluid is drawn in, a compression part configured to compress the cryogenic fluid drawn in, and an outlet through which a compressed fluid is discharged; and a heating device configured to heat the compressed fluid discharged through the outlet.

[0043] According to this aspect, the cryogenic fluid is drawn in through the inlet of the compressor. Accordingly, the compression efficiency of the compressor can be improved. The heating device heats the compressed fluid discharged through the outlet of the compressor. Accordingly, the temperature of the compressed fluid can be increased. Consequently, the requirements for low-temperature safeguards to be implemented for the downstream side of the outlet can be mitigated, suppressing an increase in the cost of manufacturing the cryogenic compression equipment. Thus, with the cryogenic compression equipment, the compression efficiency can be improved, and an increase in cost can be suppressed.

[0044] Cryogenic compression equipment according to the second aspect is the cryogenic compression equipment according to the first aspect that further includes an inlet pipe connected to the inlet of the compressor and in which the inlet pipe is a vacuum-insulated double-wall pipe.

[0045] According to this aspect, the inlet pipe is a vacuum-insulated double-wall pipe. This allows the cryogenic fluid to remain in the cryogenic temperature state, which features a reduced temperature, when drawn into the compressor. Consequently, the compression efficiency of the compressor can be improved.

[0046] Cryogenic compression equipment according to the third aspect is the cryogenic compression equipment according to the first or second aspect that further includes an outlet pipe connected to the outlet of the compressor and in which the heating device is disposed at the outlet pipe.

[0047] According to this aspect, the heating device is disposed at the outlet pipe. This facilitates the installation of the heating device.

[0048] Cryogenic compression equipment according to the fourth aspect is the cryogenic compression equipment according to the third aspect in which the outlet pipe includes a pipe section connected to the outlet, and a thermal insulation cover member configured to cover the pipe section.

[0049] According to this aspect, the outlet pipe includes the pipe section and the cover member. Accordingly, costs related to the low-temperature safeguards can be reduced.

[0050] Cryogenic compression equipment according to the fifth aspect is the cryogenic compression equipment according to the third or fourth aspect that further includes a downstream pipe connected to a downstream part of the outlet pipe and in which the heating device heats the compressed fluid to a temperature within a service temperature limit range set for the downstream pipe, the service temperature limit range including ambient temperature.

[0051] According to this aspect, the heating device heats the compressed fluid to the temperature within a service temperature limit range set for the downstream pipe, the service temperature limit range including ambient temperature. Accordingly, the requirements for low-temperature safeguards can be mitigated. Thus, an increase in the cost of the cryogenic compression equipment can be further suppressed.

[0052] Cryogenic compression equipment according to the sixth aspect is the cryogenic compression equipment according to the fifth aspect in which the downstream pipe is formed of carbon steel.

[0053] According to this aspect, the downstream pipe is formed of carbon steel. This reduces the cost of the downstream pipe. Thus, an increase in the cost of the cryogenic compression equipment can be further suppressed.

[0054] Cryogenic compression equipment according to the seventh aspect is the cryogenic compression equipment according to any one of the first to sixth aspects in which the heating device is a heat exchanger through which a heat medium flows, and causes the heat medium and the compressed fluid to exchange heat therebetween.

[0055] According to this aspect, the heating device is a heat exchanger through which the heat medium flows, and causes the heat medium and the compressed fluid to exchange heat therebetween. Accordingly, the heating device allows the heat medium to absorb cold energy from the compressed fluid. This enables the cold energy to be recycled via the heat medium.

[0056] A boil-off gas liquefaction system according to the eighth aspect includes: the cryogenic compression equipment according to any one of the first to seventh aspects; and a liquefier configured to liquefy the compressed fluid being discharged from the cryogenic compression equipment. The cryogenic compression equipment draws in boil-off gas that is a cryogenic fluid generated by vaporization of a cryogenic liquid within a liquid tank that stores the cryogenic liquid.

[0057] According to this aspect, the cryogenic compression equipment draws in the boil-off gas that is the cryogenic fluid generated by the vaporization of the cryogenic liquid within the liquid tank. Subsequently, the cryogenic compression equipment compresses and discharges the boil-off gas, and the liquefier liquefies the compressed boil-off gas discharged from the cryogenic compression equipment. This enables a boil-off gas liquefaction system capable of recycling the boil-off gas. Furthermore, as previously described, an increase in the cost of the cryogenic compression equipment can be suppressed, enabling a cost-effective boil-off gas liquefaction system.

[0058] From the foregoing description, many modifications and other embodiments of the present invention would be obvious to a person having ordinary skill in the art. Therefore, the foregoing description should be interpreted only as an example and is provided for the purpose of teaching the best mode for carrying out the present invention to a person having ordinary skill in the art. The details of the structures and / or functions of the present invention can be substantially changed without departing from the spirit of the present invention. Reference Signs List

[0059] 1   boil-off gas liquefaction system 3   liquefied hydrogen tank (liquid tank) 11   compression equipment 13    liquefier 21   compressor 21a inlet 21b   compression part 21c   outlet 22   heating device 23   inlet pipe 24   outlet pipe 24a   pipe section 24b cover member 25 downstream pipe

Claims

1. Cryogenic compression equipment comprising:a compressor including an inlet through which a cryogenic fluid is drawn in, a compression part configured to compress the cryogenic fluid drawn in, and an outlet through which a compressed fluid is discharged; anda heating device configured to heat the compressed fluid discharged through the outlet.

2. The cryogenic compression equipment according to claim 1, further comprising:an inlet pipe connected to the inlet of the compressor, wherein the inlet pipe is a vacuum-insulated double-wall pipe.

3. The cryogenic compression equipment according to claim 1, further comprising:an outlet pipe connected to the outlet of the compressor, wherein the heating device is disposed at the outlet pipe.

4. The cryogenic compression equipment according to claim 3, whereinthe outlet pipe includes a pipe section connected to the outlet, and a thermal insulation cover member configured to cover the pipe section.

5. The cryogenic compression equipment according to claim 3, further comprising:a downstream pipe connected to a downstream part of the outlet pipe, wherein the heating device heats the compressed fluid to a temperature within a service temperature limit range set for the downstream pipe, the service temperature limit range including ambient temperature.

6. The cryogenic compression equipment according to claim 5, whereinthe downstream pipe is formed of carbon steel.

7. The cryogenic compression equipment according to claim 1, whereinthe heating device is a heat exchanger through which a heat medium flows, and causes the heat medium and the compressed fluid to exchange heat therebetween.8.A boil-off gas liquefaction system comprising:the cryogenic compression equipment according to claim 1; anda liquefier configured to liquefy the compressed fluid being discharged from the cryogenic compression equipment, whereinthe cryogenic compression equipment draws in boil-off gas that is a cryogenic fluid generated by vaporization of a cryogenic liquid within a liquid tank that stores the cryogenic liquid.

Images