Cooling device and cooling method

Abstract

Provided are a cooling device and a cooling method that are capable of reducing the compression power used for cooling a raw material gas. This cooling device comprises: a gas introduction part that receives a compressed raw material gas from a raw material gas supply source; a first expansion part that allows a first portion of the raw material gas to expand; a first heat exchange part that cools a second portion of the raw material gas by using the first portion having a lowered temperature due to the expansion; and a compression part that compresses the first portion having an increased temperature due to the heat exchange, and that causes the first portion to converge with the raw material gas received from the gas introduction part.

Description

Cooling device and cooling method

[0001] The present disclosure relates to a cooling device and a cooling method.

[0002] Techniques for cooling a source gas are known. For example, Patent Document 1 discloses an apparatus for liquefying hydrogen gas by electrolyzing water stored in a water tank using a water electrolysis device and cooling the resulting hydrogen gas through heat exchange with a refrigerant circulating through a refrigeration cycle. The refrigeration cycle uses helium gas as the refrigerant gas and is a Brayton cycle equipped with a compressor that compresses the helium gas, a radiator that removes heat generated during compression, and an expansion turbine that adiabatically expands the high-pressure helium gas to generate helium gas at a temperature below the hydrogen liquefaction temperature.

[0003] Patent No. 2634266

[0004] The cooling device as disclosed in Patent Document 1 has a problem in that the compression power of the compressor is large as the power for cooling the raw material gas.

[0005] An object of the present disclosure is to provide a cooling device and a cooling method that can reduce the compression power required to cool a raw material gas.

[0006] In order to achieve the above object, the cooling device of the present disclosure includes a gas inlet section that receives compressed raw material gas from a raw material gas supply source, a first expansion section that expands a first portion of the raw material gas, a first heat exchange section that cools a second portion of the raw material gas by the first portion whose temperature has been reduced by expansion, and a compression section that compresses the first portion whose temperature has been increased by heat exchange and merges it with the raw material gas received from the gas inlet section.

[0007] The cooling method of the present disclosure also includes the steps of receiving compressed raw material gas from a raw material gas supply source, expanding a first portion of the raw material gas, cooling a second portion of the raw material gas using the first portion whose temperature has been reduced by the expansion, and compressing the first portion whose temperature has been increased and merging it with the raw material gas received from the raw material gas supply source.

[0008] The cooling device of the present disclosure also includes a gas inlet section that receives compressed raw material gas from a raw material gas supply source, a refrigeration cycle having a compression section and an expansion section and circulating a refrigerant, a heat exchange section that cools the raw material gas with the refrigerant of the refrigeration cycle, and an auxiliary expansion section that expands the raw material gas to assist the compression power of the compression section of the refrigeration cycle.

[0009] The cooling method of the present disclosure also includes the steps of receiving compressed raw material gas from a raw material gas supply source, cooling the raw material gas using a refrigerant in a refrigeration cycle having a compression section and an expansion section and circulating the refrigerant, and expanding the raw material gas to assist the compression power of the compression section of the refrigeration cycle.

[0010] The cooling device of the present disclosure also includes a refrigeration cycle having a gas inlet section that receives a raw material gas from a raw material gas supply source, a compression section that compresses the raw material gas, and an expansion section that expands the compressed raw material gas, a boost valve that compresses a second portion of the raw material gas using expansion energy of a first portion of the raw material gas and sends the expanded first portion to the compression section, and a heat exchange section that cools the second portion compressed by the boost valve with the raw material gas circulating through the refrigeration cycle.

[0011] The cooling method of the present disclosure also includes the steps of receiving a raw material gas from a raw material gas supply source, compressing a second portion of the raw material gas by a boost valve using expansion energy of a first portion of the raw material gas, cooling the second portion compressed by the boost valve by the raw material gas circulating through a refrigeration cycle having a compression section that compresses the raw material gas and an expansion section that expands the compressed raw material gas, and compressing the first portion expanded by the boost valve by the compression section.

[0012] According to the present disclosure, it is possible to provide a cooling device and a cooling method that can reduce the compression power required to cool a raw material gas.

[0013] FIG. 1 is a schematic diagram illustrating a cooling device according to the first embodiment. FIG. 2 is a diagram illustrating an example of the configuration of a raw material gas supply source according to the first embodiment. FIG. 3 is a schematic diagram illustrating a by-product gas liquefaction treatment unit. FIG. 4 is a schematic diagram illustrating a cooling device according to a first modified example of the first embodiment. FIG. 5 is a schematic diagram illustrating a cooling device according to a second modified example of the first embodiment. FIG. 6 is a schematic diagram illustrating a cooling device according to the second embodiment. FIG. 7 is a schematic diagram illustrating a cooling device according to a modified example of the second embodiment. FIG. 8 is a schematic diagram illustrating a cooling device according to the third embodiment. FIG. 9 is a schematic diagram illustrating a cooling device according to a first modified example of the third embodiment. FIG. 10 is a schematic diagram illustrating a cooling device according to a second modified example of the third embodiment. FIG. 11 is a schematic diagram illustrating a cooling device according to a third modified example of the third embodiment. FIG. 12 is a schematic diagram illustrating a cooling device according to a fourth modified example of the third embodiment. FIG. 13 is a schematic diagram illustrating a cooling device according to a fifth modified example of the third embodiment. FIG. 14 is a schematic diagram illustrating a cooling device according to a sixth modified example of the third embodiment. FIG. 15 is a schematic configuration diagram illustrating a cooling device according to a seventh modification of the third embodiment.

[0014] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that the present disclosure is not limited to these embodiments, and when there are multiple embodiments, the present disclosure also includes configurations that combine the embodiments. Furthermore, the components in the embodiments include those that can be easily imagined by a person skilled in the art, those that are substantially identical, and those that are within the so-called equivalent range.

[0015] [First embodiment] Fig. 1 is a schematic diagram showing a cooling system 1 according to a first embodiment. In the first embodiment, the cooling system 1 is configured as a liquefaction system that cools and liquefies a raw material gas 90. The cooling system 1 of the first embodiment shown in Fig. 1 is configured based on a Claude cycle.

[0016] The cooling device 1 liquefies the raw material gas 90 by cooling the raw material gas 90 to a liquefaction temperature. The raw material gas 90 becomes a liquefied gas by being liquefied. The raw material gas 90 is, for example, a low boiling point gas. Examples of low boiling point gases include, but are not limited to, hydrogen gas, oxygen gas, and nitrogen gas. Hydrogen gas becomes liquid hydrogen at a liquefaction temperature of approximately -253°C at standard pressure. Oxygen gas becomes liquid oxygen at a liquefaction temperature of approximately -183°C at standard pressure. Nitrogen gas becomes liquid nitrogen at a liquefaction temperature of approximately -196°C at standard pressure. The cooling device 1 does not necessarily have to liquefy the raw material gas 90.

[0017] (Cooling Device) The cooling device 1 includes a gas introduction section 2, an expansion section, a heat exchange section, and a compression section 8. The expansion section includes a first expansion section 3 and a second expansion section 4. The heat exchange section includes a first heat exchange section 5, a second heat exchange section 6, and a third heat exchange section 7. The cooling device 1 configured as a liquefaction device includes an expansion valve 21 and a liquid tank 22 that stores liquefied gas obtained by liquefying a raw material gas 90. In the example of Fig. 1, the cooling device 1 also includes a refrigeration cycle 30 that cools the raw material gas 90 with a refrigerant 35.

[0018] The gas introduction unit 2 receives compressed source gas 90 from the source gas supply source 23. That is, in the first embodiment, the gas introduction unit 2 receives a high-pressure source gas that has been compressed in advance. The pressure P1 of the source gas 90 in the gas introduction unit 2 is higher than atmospheric pressure. The pressure P1 is, for example, 0.5 MPa or more, and preferably 1 MPa or more. The pressure P1 is, for example, approximately 3 MPa.

[0019] The raw material gas supply source 23 that supplies the compressed raw material gas 90 can be, for example, a high-pressure gas tank or a pressure storage device such as an accumulator. The cooling device 1 can also include a raw material gas generator 50 (see FIG. 2 ), which will be described later, as the raw material gas supply source 23.

[0020] The gas introduction section 2 is connected to the second expansion section 4 via a flow path 11. The flow path 11 passes through the third heat exchange section 7 and the second heat exchange section 6 in this order. The second expansion section 4 is connected to the first expansion section 3 and the expansion valve 21 via a branched flow path 12. That is, the flow path 12 branches into two, a flow path 13A and a flow path 13B. The branched flow path 12 divides the raw material gas 90 into two, a first portion 91 and a second portion 92. The flow path 13A connects to the first expansion section 3. The flow path 13A supplies the first portion 91 of the raw material gas 90 to the first expansion section 3. The flow path 13B connects to the expansion valve 21. The flow path 13B passes through the second heat exchange section 6 and the first heat exchange section 5 in this order. The flow path 13B supplies the second portion 92 of the raw material gas 90 to the expansion valve 21 after passing through the second heat exchange section 6 and the first heat exchange section 5 .

[0021] The first expansion section 3 is connected via a flow path 14 to a return flow path 16 that connects a liquid tank 22 to the compression section 8. The expansion valve 21 is connected to the liquid tank 22 via a flow path 15. The return flow path 16 connects the liquid tank 22 and the compression section 8. The return flow path 16 passes through the first heat exchange section 5 and the third heat exchange section 7 in this order. The compression section 8 is connected to the flow path 11 via a flow path 17. The compression section 8 is connected to the flow path 11 between the gas introduction section 2 and the third heat exchange section 7.

[0022] The refrigeration cycle 30 includes a circulation flow path 33 that connects the compression section 31 and the expansion section 32. The circulation flow path 33 circulates a refrigerant 35 between the compression section 31 and the expansion section 32. The circulation flow path 33 passes through the third heat exchange section 7.

[0023] The first expansion section 3 and the second expansion section 4 each include an expansion turbine. The first expansion section 3 and the second expansion section 4 expand the raw material gas 90 that has flowed in, thereby lowering the temperature of the raw material gas 90.

[0024] The first expansion section 3 expands a first portion 91 of the source gas 90. That is, the first expansion section 3 receives and expands the first portion 91 of the source gas 90, which has been divided into a first portion 91 and a second portion 92 by the branched flow path 12. Because the second portion 92 is not supplied to the first expansion section 3, the first expansion section 3 does not expand the second portion 92. The first expansion section 3 expands the first portion 91, and supplies the first portion 91, whose temperature has been reduced by the expansion, from the flow path 14 to the return flow path 16.

[0025] The second expansion section 4 is provided upstream of the first expansion section 3. The second expansion section 4 receives and expands the raw material gas 90 before it is divided by the flow path 12. The second expansion section 4 expands the raw material gas 90 received from the flow path 11, and supplies the raw material gas 90, whose temperature has been reduced by the expansion, to the flow path 12.

[0026] In this way, the cooling device 1 expands and lowers the temperature of the high-pressure source gas 90 received from the gas inlet 2 in two stages using the first expansion section 3 and the second expansion section 4. The second expansion section 4 expands the source gas 90 to a pressure P2 lower than the pressure P1. The first expansion section 3 further expands the first portion 91 of the source gas 90 after expansion by the second expansion section 4. The second expansion section 4 expands the first portion 91 to a pressure P3 lower than the pressure P2.

[0027] The first heat exchange unit 5, the second heat exchange unit 6, and the third heat exchange unit 7 each include a heat exchanger that exchanges heat among multiple fluids. The first heat exchange unit 5, the second heat exchange unit 6, and the third heat exchange unit 7 each have one or more high-temperature side passages through which high-temperature fluids flow and one or more low-temperature side passages through which low-temperature fluids flow. The first heat exchange unit 5, the second heat exchange unit 6, and the third heat exchange unit 7 cool the fluids flowing through the high-temperature side passages by transferring heat from the fluids flowing through the high-temperature side passages to the fluids flowing through the low-temperature side passages. The first heat exchange unit 5 and the second heat exchange unit 6 each have an ortho-para conversion unit 40. The ortho-para conversion unit 40 includes a catalyst for promoting the ortho-para conversion of the feed gas 90 (hydrogen). The catalyst of the ortho-para conversion unit 40 is provided in the passage portion through which the feed gas 90 flows so as to come into contact with the feed gas 90.

[0028] The first heat exchanger 5 is disposed across the flow path 13B and the return flow path 16. In the first heat exchanger 5, the flow path 13B is a high-temperature side flow path, and the return flow path 16 is a low-temperature side flow path. The first heat exchanger 5 exchanges heat between a second portion 92 of the raw material gas 90 flowing through the flow path 13B and the raw material gas 90 flowing through the return flow path 16. The first heat exchanger 5 cools the second portion 92 of the raw material gas 90 expanded by the second expansion section 4 using the first portion 91 expanded by the second expansion section 4 and the first expansion section 3. That is, the second portion 92 of the raw material gas 90 expanded by the second expansion section 4 flows through the flow path 13B. The low-temperature first portion 91 of the raw material gas 90 expanded by the first expansion section 3 and the low-temperature raw material gas 90 from the liquid tank 22 flow through the return flow path 16. As a result, the first heat exchanger 5 cools the second portion 92 of the raw material gas 90 using the return gas containing the first portion 91.

[0029] The expansion valve 21 expands the second portion 92 cooled by the first heat exchanger 5 to liquefy at least a portion of the second portion 92. The expansion valve 21 is, for example, a Joule-Thomson valve. The expansion valve 21 cools the second portion 92 of the raw material gas 90 by expanding it. At least a portion of the second portion 92 that passes through the expansion valve 21 is liquefied. Therefore, the fluid flowing through the flow path 15 becomes a gas-liquid mixed phase state of the gas-phase raw material gas 90 (second portion 92) and the liquid-phase liquefied gas. The raw material gas 90 and the liquefied gas flow into the liquid tank 22 and are separated therein. The gas-phase raw material gas 90 that has flowed into the liquid tank 22 and the (vaporized) raw material gas 90 generated in the liquid tank 22 flow into the return flow path 16 due to the negative pressure of the compression unit 8.

[0030] The second heat exchanger 6 is disposed across the flow path 11 and the flow path 13B. In the second heat exchanger 6, the flow path 11 is a high-temperature side flow path, and the flow path 13B is a low-temperature side flow path. The second heat exchanger 6 exchanges heat between the raw material gas 90 flowing through the flow path 11 and the second portion 92 flowing through the flow path 13B. That is, the raw material gas 90 before expansion by the second expansion section 4 flows through the flow path 11. The second portion 92 of the raw material gas 90 whose temperature has been reduced by expansion in the second expansion section 4 flows through the flow path 13B. In this way, the second heat exchanger 6 cools the raw material gas 90 before expansion by the second expansion section 4 using the second portion 92 of the raw material gas 90 after expansion by the second expansion section 4.

[0031] In the flow path 13B, the second heat exchange section 6 is disposed upstream of the first heat exchange section 5, i.e., at a position closer to the branching point. Therefore, the first heat exchange section 5 cools the second portion 92 that has passed through the second heat exchange section 6 by using the first portion 91 expanded by the first expansion section 3.

[0032] The third heat exchange unit 7 is disposed across the flow path 11, the return flow path 16, and the circulation flow path 33. The third heat exchange unit 7 exchanges heat among the raw material gas 90 flowing through the flow path 11, the raw material gas 90 flowing through the return flow path 16, and the refrigerant flowing through the circulation flow path 33. In this way, the third heat exchange unit 7 cools the raw material gas 90 with the refrigerant 35.

[0033] Both the high-pressure portion 33A and the low-pressure portion 33B of the circulation flow path 33 pass through the third heat exchanger 7. Therefore, in the refrigeration cycle 30, the third heat exchanger 7 cools the high-temperature, high-pressure refrigerant flowing through the high-pressure portion 33A with the low-temperature, low-pressure refrigerant flowing through the low-pressure portion 33B. Therefore, in the third heat exchanger 7, the flow path 11 and the high-pressure portion 33A form a high-temperature side flow path, and the return flow path 16 and the low-pressure portion 33B form a low-temperature side flow path. The raw material gas 90 received in the flow path 11 from the gas inlet 2 is cooled not only by the raw material gas 90 flowing through the return flow path 16 but also by the refrigerant 35 of the refrigeration cycle 30, enabling effective cooling. As a result, the capacity of the compression section 8 can be reduced.

[0034] The compression unit 8 includes a compressor having a compression mechanism and a motor that drives the compression mechanism. The compression method of the compressor is not particularly limited. Examples of the compressor include a positive displacement compressor and a turbo compressor. The compression unit 8 increases the pressure of the raw material gas 90 that has flowed in by compressing it. The compression unit 8 includes a cooling mechanism for removing heat from the raw material gas 90 that accompanies compression. The cooling method of the cooling mechanism is not particularly limited, but is, for example, a water-cooling type.

[0035] The compression section 8 receives the raw material gas 90 via the return flow path 16. The compression section 8 compresses the raw material gas 90 received from the return flow path 16 and sends it to the flow path 11 via the flow path 17. Return gas including the first portion 91 that joins the return flow path 16 from the first expansion section 3 via the flow path 14 and the raw material gas 90 in the liquid tank 22 flows through the return flow path 16. The return gas flowing through the return flow path 16 passes through the first heat exchange section 5 and the third heat exchange section 7, and then flows into the compression section 8. The compression section 8 compresses the return gas (the raw material gas 90 from the first portion 91 and the liquid tank 22) whose temperature has been increased by heat exchange, and causes it to join the raw material gas 90 received from the gas inlet section 2.

[0036] The compression unit 8 compresses the raw material gas 90 received from the return flow path 16 to a pressure P1 in the gas inlet unit 2 and sends it to the flow path 11. In the first embodiment, the raw material gas 90 is introduced into the gas inlet unit 2, having been compressed in advance to a pressure P1 at which the raw material gas 90 can be expanded by the second expansion unit 4 and the first expansion unit 3. The compression unit 8 compresses the raw material gas 90 (return gas) at a pressure lower than the pressure of the raw material gas 90 received into the gas inlet unit 2. In other words, the compression unit 8 does not compress the raw material gas 90 received into the gas inlet unit 2, but compresses only the low-pressure raw material gas 90 (return gas) flowing through the return flow path 16. Therefore, the capacity of the compression unit 8 can be reduced compared to when compressing the entire amount of the raw material gas 90 received into the gas inlet unit 2 and the raw material gas 90 flowing through the return flow path 16.

[0037] The compression section 31 and expansion section 32 included in the refrigeration cycle 30 have the same configurations as the compression section 8 and expansion section (first expansion section 3, second expansion section 4) on the feed gas 90 side, respectively. The refrigeration cycle 30 compresses refrigerant 35 in the compression section 31, cools it using a cooling mechanism included in the compression section 31 and the third heat exchange section 7 in the high-pressure side section 33A, and then expands it in the expansion section 32 to generate low-temperature, low-pressure refrigerant 35. The refrigeration cycle 30 cools the feed gas 90 flowing through the flow path 11 by supplying the low-temperature, low-pressure refrigerant to the third heat exchange section 7 in the low-pressure side section 33B.

[0038] The refrigerant 35 used in the refrigeration cycle 30 is not particularly limited as long as it can cool the raw material gas 90 flowing through the flow path 11, and is, for example, nitrogen gas. The compression section 31 of the refrigeration cycle 30 compresses the refrigerant 35 to, for example, about 0.8 MPa. The expansion section 32 expands the refrigerant 35 to, for example, about 0.1 MPa.

[0039] (Cooling Method) Next, a cooling method according to the first embodiment will be described.

[0040] The cooling method according to the first embodiment includes a step of receiving compressed source gas 90 from a source gas supply source 23. That is, the gas introduction unit 2 receives the source gas 90 compressed to a pressure P1 from the source gas supply source 23. The gas introduction unit 2 passes the received source gas 90 through the third heat exchange unit 7 and the second heat exchange unit 6 in this order via the flow path 11, and supplies the received source gas 90 to the second expansion unit 4. The pressure P1 is, for example, approximately 3 MPa.

[0041] The third heat exchanger 7 primarily cools the raw material gas 90 flowing from the gas inlet 2 through the flow path 11 with the refrigerant of the refrigeration cycle 30 and the low-temperature, low-pressure raw material gas 90 flowing through the return flow path 16. The second heat exchanger 6 secondarily cools the raw material gas 90 in the flow path 11 that has been primarily cooled by the third heat exchanger 7 with a second portion 92 of the raw material gas 90 (the raw material gas expanded by the second expansion section 4) flowing through the flow path 13B.

[0042] The second expansion section 4 expands the raw material gas 90 from the flow path 11 and supplies it to the flow path 12. The second expansion section 4 expands the raw material gas 90 received at pressure P1 to pressure P2, which is lower than pressure P1. The raw material gas 90 from the second expansion section 4 is divided into two parts, a first part 91 and a second part 92, in the flow path 12. The first part 91 of the raw material gas 90 flows into the first expansion section 3 via the flow path 13A. The second part 92 of the raw material gas 90 passes through the second heat exchange section 6 and the first heat exchange section 5 in this order in the flow path 13B, and flows into the expansion valve 21.

[0043] The cooling method according to the first embodiment includes a step of expanding a first portion 91 of a source gas 90. That is, the first expansion section 3 expands the first portion 91 of the source gas 90 from the flow path 13A and supplies it to the return flow path 16 via the flow path 14. The first expansion section 3 expands the received first portion 91 of the source gas 90 at a pressure P2 to a pressure P3 lower than the pressure P2. The pressure P3 is, for example, approximately 0.1 MPa.

[0044] The cooling method according to the first embodiment includes a step of cooling the second portion 92 of the source gas 90 by the first portion 91 whose temperature has been reduced by expansion. That is, the first heat exchange unit 5 cools the medium-temperature and medium-pressure second portion 92 of the source gas 90 flowing through the flow path 13B by the low-temperature and low-pressure first portion 91 (and the source gas 90 from the liquid tank 22) flowing through the return flow path 16.

[0045] The expansion valve 21 expands a second portion 92 of the low-temperature, medium-pressure (pressure P2) raw material gas 90 cooled in the first heat exchanger 5. The expansion valve 21 expands the second portion 92 at pressure P2 to pressure P3 to cool it, and liquefies at least a portion of the second portion 92. As a result, a liquefied gas is generated from the raw material gas 90 and flows into the liquid tank 22 via the flow path 17. The low-temperature, low-pressure (pressure P3) raw material gas 90 in the liquid tank 22 flows into the return flow path 16.

[0046] The return flow path 16 receives the first portion 91 from the first expansion section 3 and the raw gas 90 from the liquid tank 22, passes them through the first heat exchange section 5 and the third heat exchange section 7 in sequence, and uses them to cool the raw gas 90 before sending it to the compression section 8.

[0047] The cooling method according to the first embodiment includes a step of compressing the first portion 91 whose temperature has increased and merging it with the raw material gas 90 received from the raw material gas supply source 23. That is, the compression unit 8 receives return gas at a pressure P3, which includes the first portion 91 and the raw material gas 90 from the liquid tank 22, from the return flow path 16, and compresses it to a pressure P1. The compression unit 8 removes heat generated by the compression using a cooling mechanism, and then merges the return gas compressed to the pressure P1 from the flow path 17 with the raw material gas 90 in the flow path 11.

[0048] As a result, a portion of the raw material gas 90 received in the gas inlet section 2 is liquefied and stored in the liquid tank 22. The remaining portion of the raw material gas 90 received in the gas inlet section 2 that has not been liquefied is sent from the return flow path 16 to the compression section 8, returned to the pressure P1 of the gas inlet section 2, and merges with the raw material gas 90 received in the gas inlet section 2. As a result, as the raw material gas 90 circulates through the flow path of the cooling device 1, the raw material gas 90 is successively liquefied in portions.

[0049] 2 is a diagram showing an example of the configuration of the raw material gas supply source 23 according to the first embodiment. In the example of Fig. 2, the cooling device 1 further includes, as the raw material gas supply source 23, a raw material gas generator 50 that generates a raw material gas 90 from a raw material liquid 95 and supplies the generated raw material gas 90 to the gas inlet part 2.

[0050] In the first embodiment, hydrogen gas is exemplified as the raw material gas 90. The raw material gas generator 50 generates hydrogen gas, which is the raw material gas 90, using water as a raw material liquid 95. The raw material gas generator 50 is a water electrolysis device that generates hydrogen gas and oxygen gas by electrolysis of water.

[0051] The raw material gas generation device 50 includes a raw material liquid tank 51, a pressurizing unit 52, a raw material gas generation unit 53, and a gas delivery line 54. The raw material gas generation unit 53 includes a gas-liquid separator 56 and an electrolysis device 57.

[0052] The raw material liquid tank 51 stores the raw material liquid 95. The raw material liquid tank 51 stores water as the raw material liquid 95.

[0053] The pressurizing unit 52 includes a liquid pump. The pressurizing unit 52 is connected to the raw material liquid tank 51 and the gas-liquid separator 56 via piping 55. The pressurizing unit 52 pressurizes and supplies the raw material liquid 95 stored in the raw material liquid tank 51 to the raw material gas generating unit 53. The pressurizing unit 52 compresses the raw material gas 90 by supplying the raw material liquid 95 to the raw material gas generating unit 53 under pressure. The pressurizing unit 52 includes a first pump 52A and a second pump 52B. The first pump 52A pressurizes and supplies the raw material liquid 95 stored in the raw material liquid tank 51 to the first separator 56A of the gas-liquid separator 56. The second pump 52B pressurizes and supplies the raw material liquid 95 stored in the raw material liquid tank 51 to the second separator 56B of the gas-liquid separator 56.

[0054] The gas-liquid separator 56 separates the raw material gas 90 generated from the raw material liquid 95 from the raw material liquid 95. The gas-liquid separator 56 includes a first separator 56A and a second separator 56B. The first separator 56A separates the raw material gas 90 (hydrogen gas) generated from the raw material liquid 95 from the raw material liquid 95. The second separator 56B separates oxygen gas, which serves as a by-product gas 96 generated from the raw material liquid 95, from the raw material liquid 95. The raw material gas 90 (hydrogen gas) in the first separator 56A is compressed by the raw material liquid 95 supplied under pressure from the first pump 52A. The by-product gas 96 (oxygen gas) in the second separator 56B is compressed by the raw material liquid 95 supplied under pressure from the second pump 52B.

[0055] The electrolysis device 57 electrolyzes the raw material liquid 95 to generate the raw material gas 90. The electrolysis device 57 electrolyzes water, which is the raw material liquid 95, to generate hydrogen gas, which is the raw material gas 90, and oxygen gas, which is the by-product gas 96.

[0056] The gas delivery line 54 is connected to the gas-liquid separator 56 and the gas introduction unit 2, and delivers the source gas 90 generated in the gas-liquid separator 56 to the gas introduction unit 2. The gas delivery line 54 includes a first line 54A and a second line 54B. The first line 54A connects the first separator 56A and the gas introduction unit 2. The first line 54A distributes the source gas 90. The second line 54B connects the second separator 56B and the liquefaction treatment unit 70. The second line 54B distributes the by-product gas 96.

[0057] The first line 54A and the second line 54B are provided with back pressure valves 58A, 58B and pressure regulating valves 59A, 59B. The back pressure valves 58A, 58B are disposed upstream (on the gas-liquid separator 56 side) of the pressure regulating valves 59A, 59B. The back pressure valves 58A, 58B maintain the pressure of the gas (source gas 90, by-product gas 96) from the gas-liquid separator 56 at a constant level. The pressure regulating valves 59A, 59B regulate the pressure of the gas (source gas 90, by-product gas 96) delivered from the first line 54A and the second line 54B to a set value.

[0058] In this embodiment, the gas (source gas 90, by-product gas 96) in the gas-liquid separator 56 is compressed by pressurizing and supplying the source liquid 95 by the pressurizing unit 52. The back pressure valves 58A and 58B release the gas pressure in the first separator 56A and the second separator 56B when the pressure exceeds a set value, thereby adjusting the gas pressure to the set pressure. The pressure regulating valves 59A and 59B regulate the gas that has passed through the back pressure valves 58A and 58B to a desired supply pressure. Therefore, in this embodiment, the first pump 52A of the pressurizing unit 52 pressurizes the source gas 90 to the set pressure Ps0 of the back pressure valve 58A. The set pressure Ps0 is higher than the pressure P1 supplied to the gas inlet 2. The set pressure Ps0 is not particularly limited, but is, for example, approximately 30 MPa. The pressure regulating valve 59A adjusts the pressure of the source gas 90 to the pressure P1 supplied to the gas inlet 2. As a result, the raw material gas generator 50 introduces the raw material gas 90 adjusted to the pressure P1 into the gas inlet part 2.

[0059] 2 , the cooling device 1 can cool and liquefy the by-product gas 96 using the liquefaction treatment unit 70, in the same way as the source gas 90. The source gas generator 50 introduces the by-product gas 96, compressed to a pressure Ps1, into the liquefaction treatment unit 70 for the by-product gas 96. The second pump 52B of the pressurizing unit 52 pressurizes the by-product gas 96 to the set pressure Ps1 of the back-pressure valve 58B. The pressure adjustment valve 59B reduces the pressure of the by-product gas 96 to a pressure at which the by-product gas 96 is supplied to the liquefaction treatment unit 70. The supply pressure of the by-product gas 96 is, for example, approximately 0.1 MPa.

[0060] 3 is a schematic diagram showing a liquefaction treatment unit 70 for the by-product gas 96. The liquefaction treatment unit 70 includes a by-product gas flow path 71, a refrigeration cycle 72, heat exchange units 73 and 74, and a liquid tank 75 for the by-product gas 96. In this example, the by-product gas 96 is oxygen gas, as described above.

[0061] The by-product gas flow path 71 receives the by-product gas 96 from the raw material gas generator 50 and sends it to the liquid tank 75 .

[0062] The refrigeration cycle 72 includes a compression section 76, an expansion section 77, and a refrigerant circulation flow path 78. The refrigeration cycle 72 has a configuration similar to that of the refrigeration cycle 30 shown in FIG. 1 . The refrigerant is, for example, nitrogen gas. The refrigeration cycle 72 compresses the refrigerant using the compression section 76, cools it using a cooling mechanism provided in the compression section 76 and a heat exchange section 73 in the high-pressure side section 78A, and then expands it using the expansion section 77 to generate a low-temperature, low-pressure refrigerant. The compression section 76 compresses the refrigerant to approximately 0.8 MPa, and the expansion section 77 expands the refrigerant to approximately 0.1 MPa. The refrigeration cycle 72 sequentially supplies the low-temperature, low-pressure refrigerant to the heat exchange sections 74 and 73 in the low-pressure side section 78B.

[0063] The heat exchanger 73 primarily cools the by-product gas 96 flowing through the by-product gas flow path 71 with the refrigerant of the refrigeration cycle 30. The heat exchanger 74 secondarily cools the by-product gas 96 in the by-product gas flow path 71, which has been primarily cooled by the heat exchanger 73, with the refrigerant of the refrigeration cycle 30. The heat exchanger 74 liquefies at least a portion of the by-product gas 96 through secondary cooling. As a result, the liquefaction treatment unit 70 generates a liquefied gas (liquid oxygen) from the by-product gas 96 and sends it to the liquid tank 75.

[0064] With this configuration, in the first embodiment, the cooling device 1 generates high-pressure (pressure P1) hydrogen gas and oxygen gas by electrolysis using water as the raw material liquid 95. The cooling device 1 cools the high-pressure (pressure P1) hydrogen gas as the raw material gas 90 to generate liquid hydrogen. The cooling device 1 cools the oxygen gas as a by-product gas 96 to generate liquid oxygen.

[0065] [First Modification of First Embodiment] Fig. 4 is a schematic diagram showing a cooling device 1A according to a first modification of the first embodiment. The cooling device 1A does not include a refrigeration cycle 30 and a third heat exchanger 7, as compared with the cooling device 1 of the first embodiment shown in Fig. 1 . Also, while the cooling device 1 of Fig. 1 is provided with a two-stage expansion section, consisting of a first expansion section 3 and a second expansion section 4, the cooling device 1A of Fig. 4 performs a single-stage expansion with only the first expansion section 3. Therefore, the cooling device 1A does not include a second expansion section 4 or a second heat exchanger 6.

[0066] The flow path 11 passes from the gas inlet section 2 through the heat exchange section 81 and the heat exchange section 82 in that order, and branches into a branch path 83A and a branch path 83B. The branch path 83A is connected to the first expansion section 3. The branch path 83B passes through the first heat exchange section 5 and connects to the expansion valve 21. The heat exchange section 81, the heat exchange section 82, and the first heat exchange section 5 each have an ortho-parallel conversion section 40.

[0067] The discharge port of the first expansion section 3 is connected to a return flow path 16 from a liquid tank 22 via a flow path 14. The expansion valve 21 is connected to the liquid tank 22 via a flow path 15. After merging with the flow path 14, the return flow path 16 passes through the first heat exchange section 5, the heat exchange section 82, and the heat exchange section 81 in this order, and is connected to the compression section 8. The discharge port of the compression section 8 is connected to a position between the gas inlet section 2 and the heat exchange section 81 of the flow path 11 via a flow path 17.

[0068] As a result, the first expansion section 3 expands a first portion 91 of the raw material gas 90 supplied from the branch line 83A. The first heat exchange section 5 cools a second portion 92 of the raw material gas 90 supplied from the branch line 83B by the return gas flowing through the return flow path 16. The return gas flowing through the return flow path 16 includes the first portion 91 whose temperature has been reduced by expansion in the first expansion section 3 and the raw material gas 90 from the liquid tank 22. The compression section 8 compresses the return gas including the first portion 91 whose temperature has been increased by heat exchange, and merges it with the raw material gas 90 received from the gas inlet section 2.

[0069] [Second Modification of First Embodiment] Fig. 5 is a schematic diagram illustrating a cooling device 1B according to a second modification of the first embodiment. In the cooling device 1B, a refrigeration cycle 30 and a third heat exchanger 7 are provided instead of the heat exchanger 81 of the cooling device 1A shown in Fig. 4. The third heat exchanger 7 spans the flow path 11 and the return flow path 16 between the gas inlet 2 and the heat exchanger 82. The third heat exchanger 7 cools the source gas 90 flowing through the flow path 11 using the refrigerant 35 of the refrigeration cycle 30. Since the cooling device 1B can effectively lower the temperature of the source gas 90 by pre-cooling using the refrigeration cycle 30, the compression power in the compression section 8 can be reduced compared to the cooling device 1A shown in Fig. 4.

[0070] 6 is a schematic diagram showing a cooling device 101 according to a second embodiment. In the second embodiment, similar to the first embodiment, the cooling device 101 is configured as a liquefaction device that cools and liquefies the raw material gas 90, but the method of reducing the motor power is different.

[0071] The cooling device 101 according to the second embodiment includes a gas introduction section 102, a refrigeration cycle 103, a heat exchange section 104, and an auxiliary expansion section 105. The cooling device 101 also includes a cooling section 106 that uses a second refrigerant 192. The heat exchange section 104 includes a heat exchanger 107, a heat exchanger 108, and a heat exchanger 109.

[0072] The gas inlet 102 receives a compressed source gas 90 from the source gas supply source 23. The source gas 90 is, for example, a low-boiling-point gas. The low-boiling-point gas is, for example, hydrogen gas. The source gas 90 has a pressure P11. The pressure P11 is higher than atmospheric pressure, for example, 0.5 MPa or more, and preferably 1 MPa or more. The pressure P11 is, for example, approximately 30 MPa. The gas inlet 102 sends the source gas 90 into the flow path 111.

[0073] The flow path 111 runs from the gas inlet section 102 through the heat exchanger 107 , the heat exchanger 108 and the heat exchanger 109 in this order, and is connected to the auxiliary expansion section 105 .

[0074] The refrigeration cycle 103 is a gas refrigeration cycle that uses the same low-boiling-point gas (hydrogen) as the feed gas 90 as the refrigerant 191. The refrigeration cycle 103 includes a compression section 121, a cooling mechanism 122, an expansion section 123, and a circulation flow path 124 that connects these sections. The expansion section 123 includes an expansion valve 125 and an expansion turbine 126. The circulation flow path 124 passes through heat exchangers 107, 108, and 109. The refrigeration cycle 103 compresses the refrigerant 191 using the compression section 121, and removes heat from the refrigerant 191 whose temperature has increased due to compression using the cooling mechanism 122. The cooling mechanism 122 is, for example, water-cooled. The refrigeration cycle 103 liquefies the refrigerant 191 by expanding the low-temperature, high-pressure gas-phase refrigerant 191 (refrigerant hydrogen gas) using the expansion turbine 126 and the expansion valve 125, respectively. The refrigeration cycle 103 cools the raw material gas 90 (raw material hydrogen gas) by exchanging heat between the liquid phase refrigerant 191 (refrigerant liquid hydrogen) and the raw material gas 90 in the heat exchangers 107 and 109 .

[0075] Cooling unit 106 includes a storage tank 131 that stores liquid-phase second refrigerant 192, a refrigerant supply path 132 that supplies liquid-phase second refrigerant 192 to storage tank 131, and a refrigerant discharge path 133 that discharges gas-phase second refrigerant 192 generated in storage tank 131. Refrigerant discharge path 133 passes through heat exchanger 107. Second refrigerant 192 is, for example, nitrogen.

[0076] The heat exchange unit 104 cools the raw material gas 90 with a refrigerant 191 of the refrigeration cycle 103. The heat exchange unit 104 also cools the raw material gas 90 with a second refrigerant 192 of the cooling unit 106. The heat exchange unit 104 cools the raw material gas 90 in three stages using a heat exchanger 107, a heat exchanger 108, and a heat exchanger 109.

[0077] The heat exchanger 107 cools the raw material gas 90 by heat exchange between the raw material gas 90 (raw material hydrogen gas), the refrigerant 191 (refrigerant hydrogen) of the refrigeration cycle 103, and the gas-phase second refrigerant 192 (refrigerant nitrogen gas) of the cooling section 106.

[0078] The heat exchanger 108 is provided inside the storage tank 131 of the cooling unit 106 and is immersed in a liquid-phase second refrigerant 192. A catalyst unit 134 for promoting ortho-para conversion of the feed hydrogen is provided in a passage portion of the heat exchanger 108 through which the feed gas 90 flows. The heat exchanger 108 cools the feed gas 90 (feed hydrogen gas) and the refrigerant 191 (refrigerant hydrogen) of the refrigeration cycle 103 using the liquid-phase second refrigerant 192 in the storage tank 131. Inside the storage tank 131, the second refrigerant 192 is vaporized by heat received from the heat exchanger 108 and is discharged from a refrigerant discharge path 133. The gas-phase second refrigerant 192 flowing through the refrigerant discharge path 133 is used for heat exchange in the preceding heat exchanger 107.

[0079] The heat exchanger 109 cools the feed gas 90 (feed hydrogen gas) by heat exchange between the feed gas 90 and a refrigerant 191 of the refrigeration cycle 103. A catalyst section 134 for promoting ortho-para conversion of the feed hydrogen is provided in a passage portion of the heat exchanger 109 through which the feed gas 90 flows.

[0080] The auxiliary expansion section 105 receives, via the flow path 111, the raw material gas 90 that has been cooled by passing through the heat exchange section 104. In the second embodiment, the raw material gas 90 is introduced into the gas inlet section 102 in a compressed state to pressure P11, cooled by the heat exchange section 104, and then supplied to the auxiliary expansion section 105. The auxiliary expansion section 105 expands the raw material gas 90 at pressure P11. The auxiliary expansion section 105 expands the raw material gas 90 to assist the compression power of the compression section 121 of the refrigeration cycle 103. In addition, in the cooling device 101 configured as a liquefaction device, the auxiliary expansion section 105 expands the raw material gas 90 that has been cooled by passing through the heat exchange section 104 from the gas inlet section 102, thereby assisting the compression power of the compression section 121 and lowering the temperature of the raw material gas 90 to liquefy at least a portion of the raw material gas 90. The auxiliary expansion section 105 liquefies, for example, all of the raw material gas 90 introduced from the flow path 111.

[0081] Here, the compression unit 121 of the refrigeration cycle 103 includes a compression turbine 127 that compresses the refrigerant 191 by rotation, and a drive unit 128 that rotationally drives the compression turbine 127. The drive unit 128 is, for example, an electric motor, and is connected to a rotary shaft 129 of the compression turbine 127. The compression unit 121 is a turbo compressor that compresses the refrigerant 191 by the drive unit 128 rotating the compression turbine 127.

[0082] The auxiliary expansion section 105 includes an expansion turbine 113 connected to a compression turbine 127. The expansion turbine 113 is connected to a rotary shaft 129 of the compression turbine 127 and rotates integrally with the compression turbine 127. The auxiliary expansion section 105 expands the received raw material gas 90 at pressure P11 to a pressure P12 lower than the pressure P11, thereby rotating the expansion turbine 113. The compression power required to rotate the compression turbine 127 is reduced by the amount of rotational power applied to the expansion turbine 113. The auxiliary expansion section 105 is connected to an outlet line 112. The liquefied gas (liquid hydrogen) expanded to pressure P12 is delivered to the outlet line 112. The pressure P12 is, for example, approximately 0.1 MPa. In this case, the auxiliary expansion section 105 receives the raw material gas 90 at a pressure of 30 MPa and a temperature of −250° C., and expands it to produce liquid hydrogen at a pressure of 0.1 MPa and a temperature of −253° C. The outlet line 112 supplies the liquid hydrogen to, for example, a liquid tank or a facility that utilizes the liquefied gas.

[0083] The cooling device 101 according to the second embodiment may further include, as the raw material gas supply source 23, a raw material gas generator 50 that generates a raw material gas 90 from a raw material liquid 95 and supplies the generated raw material gas 90 to the gas inlet 102. That is, as shown in FIG. 2 , the raw material gas generator 50 may be connected to the gas inlet 102 as the raw material gas supply source 23, the raw material gas generator 50 having a raw material gas generator 53 and a pressurizing unit 52 that compresses the raw material gas 90 by supplying the raw material liquid 95 to the raw material gas generator 53 under pressure.

[0084] (Cooling Method) Next, a cooling method according to the second embodiment will be described.

[0085] The cooling method according to the second embodiment includes a step of receiving compressed source gas 90 from source gas supply source 23. That is, gas inlet unit 102 receives source gas 90 compressed to pressure P11 from source gas supply source 23. Gas inlet unit 102 passes the received source gas 90 through heat exchangers 107, 108, and 109 in this order via flow path 111, and supplies the received source gas 90 to auxiliary expansion section 105.

[0086] The cooling method according to the second embodiment includes a step of cooling a feed gas 90 with a refrigerant 191 in a refrigeration cycle 103 having a compression section 121 and an expansion section 123 and circulating the refrigerant 191. That is, the refrigeration cycle 103 compresses the refrigerant 191 in the compression section 121 and removes heat from the refrigerant 191 in a high-pressure gas phase in the cooling mechanism 122, and passes the refrigerant 191 sequentially through a heat exchanger 107, a heat exchanger 108, and a heat exchanger 109. The expansion section 123 (an expansion turbine 126 and an expansion valve 125) expands the low-temperature, high-pressure refrigerant hydrogen gas to liquefy the refrigerant 191. The refrigeration cycle 103 cools the feed gas 90 by exchanging heat between the liquid-phase refrigerant 191 (liquid hydrogen refrigerant) and the feed gas 90 in the heat exchangers 107 and 109.

[0087] The heat exchanger 107 cools the raw gas 90 in the flow path 111 and the gas-phase refrigerant 191 (refrigerant hydrogen gas) in the circulation flow path 124 using the gas-phase second refrigerant 192 (refrigerant nitrogen gas) sent from the cooling section 106 to the refrigerant discharge path 133 and the liquid-phase refrigerant 191 (refrigerant liquid hydrogen) of the refrigeration cycle 103.

[0088] The heat exchanger 108 cools the raw material gas 90 in the flow path 111 and the gas phase refrigerant 191 (hydrogen gas refrigerant) in the circulation flow path 124 using a liquid phase second refrigerant 192 (liquefied nitrogen) stored in a storage tank 131.

[0089] The heat exchanger 109 cools the raw material gas 90 in the flow path 111 and the refrigerant 191 before expansion by using the liquid-phase refrigerant 191 (liquid hydrogen refrigerant) of the refrigeration cycle 103 .

[0090] The cooling method according to the second embodiment includes a step of expanding a feed gas 90 to assist the compression power of the compression section 121 of the refrigeration cycle 103. That is, the auxiliary expansion section 105 expands the low-temperature, high-pressure (pressure P11) feed gas 90 received from the flow path 111. The auxiliary expansion section 105 rotates the expansion turbine 113 by expanding the feed gas 90, thereby assisting the compression power of the compression section 121 (compression turbine 127) connected to the expansion turbine 113. The auxiliary expansion section 105 then expands the feed gas 90 from pressure P11 to pressure P12 (<P11), thereby lowering the temperature of the feed gas 90, and liquefies the feed gas 90 due to the temperature drop. As a result, the feed gas 90 becomes a liquefied gas (liquid hydrogen) and is sent out from the outlet path 112.

[0091] [Modification of Second Embodiment] Fig. 7 is a schematic diagram showing a cooling device 101A according to a modification of the second embodiment. The cooling device 101A differs from the cooling device 101 of the second embodiment shown in Fig. 6 in the connection of the flow path 111 to the auxiliary expansion section 105. The cooling device 101A of Fig. 7 further includes an expansion valve 140 that expands and liquefies the raw material gas 90.

[0092] In the cooling device 101A of Figure 7, the flow path 111 passes from the gas introduction section 102 through the auxiliary expansion section 105, then passes through the heat exchange section 104 (heat exchanger 107, heat exchanger 108 and heat exchanger 109) and connects to the expansion valve 140.

[0093] The auxiliary expansion section 105 receives the raw material gas 90 before being cooled by the heat exchange section 104. The raw material gas 90 is introduced into the gas inlet section 102 in a state compressed to pressure P11 and is supplied to the auxiliary expansion section 105 as is (without passing through the heat exchange section 104). The auxiliary expansion section 105 expands the raw material gas 90 at pressure P11 to pressure P13. The auxiliary expansion section 105 expands the raw material gas 90 to assist the compression power of the compression section 121 of the refrigeration cycle 103. The auxiliary expansion section 105 also expands the raw material gas 90 to lower the temperature of the raw material gas 90. In this way, the auxiliary expansion section 105 expands the raw material gas 90 received from the gas inlet section 102 to assist the compression power of the compression section 121 and lower the temperature of the raw material gas 90 before sending it to the heat exchange section 104. The pressure P11 is, for example, about 30 MPa, and the pressure P13 is, for example, greater than 0.1 MPa and equal to or less than about 1 MPa. The auxiliary expansion section 105 receives the source gas 90 at, for example, about 20°C, and reduces the temperature of the source gas 90 to about -50°C by expansion.

[0094] As described above, in the cooling device 101 of the second embodiment shown in FIG. 6, the auxiliary expansion section 105 is arranged after the heat exchange section 104 and serves the function of liquefying the raw material gas 90 by expanding it, whereas in the cooling device 101A of the modified example, the auxiliary expansion section 105 is arranged before the heat exchange section 104 and serves the function of pre-cooling the raw material gas 90 introduced into the device.

[0095] On the other hand, both the cooling device 101 of the second embodiment shown in Figure 6 and the cooling device 101A of the modified example are similar in that the raw material gas 90 is expanded to rotate the expansion turbine 113, thereby assisting the compression power of the compression section 121 (compression turbine 127) connected to the expansion turbine 113.

[0096] In the cooling device 101A according to the modified example, the raw material gas 90 expanded to a pressure P13 by the auxiliary expansion section 105 is cooled by passing through the heat exchanger 107, the heat exchanger 108, and the heat exchanger 109 in sequence, and then supplied to the expansion valve 140.

[0097] The expansion valve 140 expands the raw material gas 90 (raw material hydrogen gas). The expansion valve 140 is, for example, a Joule-Thomson valve. The expansion valve 140 expands the raw material gas 90 from a pressure P13 to a pressure P14 (<P13), thereby cooling the raw material gas 90 and liquefying the gas phase raw material gas 90. The expansion valve 140 is connected to the outlet line 112. The expansion valve 140 liquefies the raw material gas 90 and sends the liquefied gas to the outlet line 112. The expansion valve 140 expands the raw material gas 90 from, for example, about 1 MPa to about 0.1 MPa, and cools the raw material gas 90 to the liquefaction temperature (about -253°C).

[0098] The other configurations of the cooling device 101A according to the modified example are similar to those of the cooling device 101 according to the second embodiment.

[0099] 8 is a schematic diagram showing a cooling device 201 according to a third embodiment. In the third embodiment, similar to the first and second embodiments, the cooling device 201 is configured as a liquefaction device that cools and liquefies the raw material gas 90, but the method of reducing the motor power is different.

[0100] The cooling device 201 according to the third embodiment includes a gas introduction section 202, a refrigeration cycle 203, a pressure booster valve 204, and a heat exchanger section 205. The cooling device 201 configured as a liquefaction device for the raw material gas 90 further includes an expansion valve 221 and a liquid tank 222. The heat exchanger section 205 includes a heat exchanger 206, a heat exchanger 207, and a heat exchanger 208. The cooling device 201 according to the third embodiment is a cycle based on the Brayton cycle and provided with a pressure booster valve 204.

[0101] The gas inlet 202 receives the raw material gas 90 from the raw material gas supply source 23. In the cooling device 201 according to the third embodiment, the raw material gas 90 received by the gas inlet 202 may be compressed in advance or may not be compressed. In the example of FIG. 8 , the gas inlet 202 receives the uncompressed raw material gas 90. The pressure of the raw material gas 90 is set to a pressure P21 equivalent to atmospheric pressure (approximately 0.1 MPa). The gas inlet 202 is connected to a compression section 231 of the refrigeration cycle 203 by a flow path 211.

[0102] The refrigeration cycle 203 has a compression section 231 that compresses the raw material gas 90 and an expansion section 232 that expands the compressed raw material gas 90. In the example of Fig. 8 , the expansion section 232 includes a first expansion section 233 and a second expansion section 234. The refrigeration cycle 203 has a circulation flow path 235 that circulates the raw material gas 90 between the compression section 231 and the expansion section 232. In the third embodiment, the refrigeration cycle 203 circulates a portion of the raw material gas 90 as a refrigerant and cools another portion of the raw material gas 90 as a cooling target.

[0103] The circulation flow path 235 includes a high-pressure side portion 236A extending from the compression section 231 toward the expansion section 232 and a low-pressure side portion 236B extending from the expansion section 232 toward the compression section 231 .

[0104] The compression unit 231 includes a compressor having a compression mechanism and a motor that drives the compression mechanism. The compression method of the compressor is not particularly limited. The compression unit 231 includes a cooling mechanism for removing heat from the source gas 90 due to compression. The cooling method of the cooling mechanism is not particularly limited, but may be, for example, a water-cooled type. The compression unit 231 receives the source gas 90 from the gas inlet unit 202 via the flow path 211. The compression unit 231 also receives the circulating source gas 90 from the low-pressure side portion 236B of the circulation flow path 235. The compression unit 231 also receives the source gas 90 discharged from the pressure boost valve 204 via the exhaust path 215. The compression unit 231 compresses the source gas 90 received from these respective units and sends it to the flow path 212. The compression unit 231 compresses the source gas 90 to a pressure P22 higher than the pressure P21.

[0105] The flow path 212 is a branch flow path that branches into two, a flow path 213 and a high-pressure side portion 236A (circulation flow path 235). The flow path 212 divides the high-pressure raw material gas 90 compressed in the compression unit 231 into a material to be cooled and a refrigerant, and supplies them to the flow path 213 and the high-pressure side portion 236A of the refrigeration cycle 203, respectively. The flow path 213 is connected to the boost valve 204. The flow path 213 supplies the raw material gas 90 to be cooled to the boost valve 204. The raw material gas 90 that serves as a refrigerant is supplied to the high-pressure side portion 236A of the refrigeration cycle 203. Therefore, the compression unit 231 supplies a portion of the compressed raw material gas 90 to the boost valve 204, and circulates the remaining portion of the compressed raw material gas 90 in the refrigeration cycle 203.

[0106] The high-pressure side portion 236A branches into a high-pressure flow path 237 that connects to the first expansion portion 233 and a high-pressure flow path 238 that connects to the second expansion portion 234. The high-pressure side portion 236A branches into the high-pressure flow path 237 and the high-pressure flow path 238 at a branching point between the heat exchangers 206 and 207. The high-pressure flow path 237 passes through the heat exchangers 207 and 208 and connects to the first expansion portion 233. The high-pressure flow path 238 connects directly from the branching point (without passing through a heat exchanger) to the second expansion portion 234.

[0107] The first expansion section 233 and the second expansion section 234 each include an expansion turbine. The first expansion section 233 and the second expansion section 234 expand the raw material gas 90 that has flowed in, thereby lowering the temperature of the raw material gas 90.

[0108] The first expansion section 233 expands the raw material gas 90 received from the high-pressure passage 237 and sends it to the low-pressure side section 236B. The low-pressure side section 236B passes from the first expansion section 233 through the heat exchanger 208, the heat exchanger 207, and the heat exchanger 206 in that order and is connected to the compression section 231. The second expansion section 234 expands the raw material gas 90 received from the high-pressure passage 238 and sends it to the connection path 239. The connection path 239 connects the second expansion section 234 to the low-pressure side section 236B. The connection path 239 connects to the low-pressure side section 236B at a connection position between the heat exchanger 208 and the heat exchanger 207.

[0109] In the refrigeration cycle 203, the raw material gas 90, which serves as a refrigerant and is sent from the compression section 231 to the high-pressure side section 236A, is cooled in the heat exchanger 206, and then divided and supplied to the first expansion section 233 and the second expansion section 234. In the refrigeration cycle 203, the raw material gas 90, which has been cooled in the heat exchangers 207 and 208, is expanded and its temperature is reduced in the first expansion section 233, and then the raw material gas 90 passes as a refrigerant through the heat exchangers 208, 207, and 206 in this order. In the refrigeration cycle 203, the raw material gas 90 is expanded and its temperature is reduced in the second expansion section 234, and then the raw material gas 90 is merged with the low-pressure side section 236B via the connecting path 239, and then passes through the heat exchangers 207 and 206 in this order. The refrigeration cycle 203 cools the raw gas 90 passing through the high-pressure side portion 236A and the raw gas 90 to be cooled (the second portion B2 described later) using the low-temperature, low-pressure raw gas 90 flowing through the low-pressure side portion 236B.

[0110] The booster valve 204 is a device that divides a supplied fluid and compresses one fluid using the pressure energy of the other fluid. The booster valve 204 is connected to a flow path 213, a flow path 214, and an exhaust path 215. The booster valve 204 receives the source gas 90 to be cooled from the flow path 213. The booster valve 204 compresses a second portion B2 of the source gas 90 using the expansion energy of a first portion B1 of the received source gas 90. The booster valve 204 expands the first portion B1 to a pressure P23 that is lower than a pressure P22. The booster valve 204 compresses the second portion B2 to a pressure P24 that is higher than the pressure P22. The booster valve 204 sends the compressed second portion B2 to the flow path 214. The flow path 214 passes through the heat exchangers 206, 207, and 208 and is connected to the expansion valve 221. The boost valve 204 sends the expanded first portion B1 to the exhaust path 215. As a result, the boost valve 204 sends the expanded first portion B1 to the compression section 231.

[0111] The first portion B1 discharged from the boost valve 204 is compressed in the compression section 231 together with the raw material gas 90 introduced into the compression section 231 from the gas inlet section 202 and the raw material gas 90 returned to the compression section 231 from the low-pressure side section 236B, and is sent to the flow path 212. The raw material gas 90 including the first portion B1 is compressed by the compression section 231 and returned to the original pressure P22. A portion of the raw material gas 90 sent from the compression section 231 to be cooled is sent to the boost valve 204 via the flow path 213. In this way, the boost valve 204 compresses the second portion B2 of the raw material gas 90 compressed to the predetermined pressure P22 by the compression section 231 using the first portion B1, and the compression section 231 recompresses the first portion B1 expanded by the boost valve 204 to the predetermined pressure P22 and supplies it to the boost valve 204.

[0112] The heat exchangers 206, 207, and 208 each exchange heat among multiple fluids. The heat exchangers 206, 207, and 208 each have one or more high-temperature side passages through which high-temperature fluids flow and one or more low-temperature side passages through which low-temperature fluids flow. The heat exchangers 206, 207, and 208 cool the fluids flowing through the high-temperature side passages by transferring heat from the fluids flowing through the high-temperature side passages to the fluids flowing through the low-temperature side passages. The heat exchangers 206, 207, and 208 each have an ortho-para conversion unit 240 containing a catalyst for promoting the ortho-para conversion of the feed gas 90 (hydrogen). The catalyst of the ortho-para conversion unit 240 is provided in a passage portion through which the feed gas 90 flows so as to come into contact with the feed gas 90.

[0113] The heat exchangers 206, 207, and 208 are respectively disposed across the high-pressure side portion 236A and the low-pressure side portion 236B of the circulation flow path 235 and the flow path 214. The heat exchangers 206, 207, and 208 cool the source gas 90 (the high-pressure second portion B2 to be cooled) flowing through the flow path 214 by the source gas 90 (the low-temperature, low-pressure source gas 90 functioning as a refrigerant) flowing through the low-pressure side portion 236B. In this manner, the heat exchange unit 205 (the heat exchangers 206, 207, and 208) cools the second portion B2 compressed by the pressure boost valve 204 by the source gas 90 flowing through the refrigeration cycle 203. Furthermore, the heat exchangers 206 , 207 , and 208 cool the raw material gas 90 flowing through the high-pressure side portion 236 A of the circulation flow path 235 by using the raw material gas 90 flowing through the low-pressure side portion 236 B.

[0114] The expansion valve 221 is connected to the flow path 214 and the flow path 216. The expansion valve 221 receives, via the flow path 214, the second portion B2 of the raw material gas 90 compressed by the compression section 231 and the booster valve 204. As the second portion B2 flows through the flow path 214, it is cooled by the heat exchanger 205 and becomes a low-temperature, high-pressure state. The expansion valve 221 expands the second portion B2 cooled by the heat exchanger 205, thereby liquefying at least a portion of the second portion B2. The expansion valve 221 is, for example, a Joule-Thomson valve. The expansion valve 221 cools the second portion B2 of the raw material gas 90 by expanding it. At least a portion of the second portion B2 that passes through the expansion valve 221 is liquefied. Therefore, the fluid flowing through the flow path 216 is in a gas-liquid mixed phase state of the gas-phase raw material gas 90 (the second portion B2) and the liquid-phase liquefied gas.

[0115] The flow path 216 connects the expansion valve 221 and the liquid tank 222. The liquid tank 222 receives the raw material gas 90 and the liquefied gas via the flow path 216. The raw material gas 90 and the liquefied gas flow into the liquid tank 222 and are separated within the liquid tank 222. The gas-phase raw material gas 90 that has flowed into the liquid tank 222 and the raw material gas 90 generated (vaporized) within the liquid tank 222 flow into the gas flow path 217.

[0116] (Cooling Method) Next, a cooling method according to the third embodiment will be described.

[0117] The cooling method according to the third embodiment includes a step of receiving a raw material gas 90 from a raw material gas supply source 23. That is, the gas introduction unit 202 receives the raw material gas 90 from the raw material gas supply source 23. The gas introduction unit 202 supplies the received raw material gas 90 to the compression unit 231 through a flow path 211.

[0118] The compression unit 231 compresses the raw material gas 90 supplied from the flow path 211 and sends it to the flow path 212. The compression unit 231 compresses the raw material gas 90 from pressure P21 to pressure P22, which is higher than pressure P21. The pressure P21 is, for example, approximately 0.1 MPa. The pressure P22 is, for example, approximately 0.8 MPa. The flow path 212 divides the high-pressure raw material gas 90 compressed in the compression unit 231 into a material to be cooled and a refrigerant, and supplies them to the flow path 213 and the high-pressure side portion 236A of the refrigeration cycle 203, respectively. The flow path 213 supplies the raw material gas 90 to be cooled to the pressure boost valve 204.

[0119] The cooling method according to the third embodiment includes a step of compressing a second portion B2 of the source gas 90 using the expansion energy of a first portion B1 of the source gas 90 with a pressure booster valve 204. The pressure booster valve 204 separates the source gas 90 received from the flow path 213 into the first portion B1 and the second portion B2, and compresses the second portion B2 by expanding the first portion B1. The pressure booster valve 204 expands the first portion B1 to a pressure P23 (<P22) and sends it to the exhaust path 215, and compresses the second portion B2 to a pressure P24 (>P22) and sends it to the flow path 214. The pressure P23 is, for example, approximately 0.1 MPa. The pressure P24 is, for example, approximately 1.6 MPa.

[0120] The cooling method according to the third embodiment includes a step of cooling a second portion B2 compressed by a pressure booster valve 204 using a raw material gas 90 flowing through a refrigeration cycle 203 having a compression section 231 that compresses the raw material gas 90 and an expansion section 232 that expands the compressed raw material gas 90. Specifically, the refrigeration cycle 203 compresses the raw material gas 90 in the compression section 231, removes heat from the raw material gas 90 in a high-pressure gas phase, and cools the raw material gas 90 by passing the raw material gas 90 sequentially through heat exchangers 206, 207, and 208. The expansion section 232 (first expansion section 233, second expansion section 234) expands the raw material gas 90 at a low temperature and high pressure (pressure P22), thereby lowering the temperature. The outlet pressures of the first expansion section 233 and the second expansion section 234 are, for example, approximately 0.1 MPa. The refrigeration cycle 203 uses low-temperature, low-pressure raw gas 90 as a refrigerant and passes it through heat exchangers 208, 207, and 206 in this order. The heat exchangers 206, 207, and 208 cool the raw gas 90 (second portion B2) flowing through a flow path 214 using the low-temperature, low-pressure raw gas 90 of the refrigeration cycle 203. The flow path 214 supplies the cooled raw gas 90 (second portion B2) to an expansion valve 221.

[0121] The expansion valve 221 expands the second portion B2 of the raw material gas 90 to liquefy at least a part of the second portion B2. The expansion valve 221 sends a gas-liquid mixed-phase fluid of the gas-phase raw material gas 90 (second portion B2) and the liquid-phase liquefied gas to the liquid tank 222 via the flow path 216. As a result, the cooling device 201 serving as a liquefaction device stores the produced liquefied gas (liquid hydrogen) in the liquid tank 222.

[0122] The cooling method according to the third embodiment includes a step of compressing the first portion B1 expanded by the booster valve 204 using the compression unit 231. That is, the first portion B1 used to compress the second portion B2 by the booster valve 204 is supplied to the compression unit 231 via the exhaust path 215. The compressed first portion B1 is compressed to a pressure P22 together with the raw material gas 90 from the gas inlet 202 and the raw material gas 90 from the low-pressure side portion 236B of the circulation path 235. The compressed raw material gas 90 is again divided into two by the path 212 and supplied to the path 213 and the high-pressure side portion 236A of the refrigeration cycle 203.

[0123] Therefore, in the third embodiment, the raw material gas 90 is circulated by the refrigeration cycle 203, and the raw material gas 90 (first portion B1) is circulated between the compression section 231 and the boost valve 204. The raw material gas 90 (first portion B1) is circulated between the compression section 231 and the boost valve 204, whereby the raw material gas 90 (second portion B2) to be cooled is compressed in two stages. In the third embodiment, compression by the compression section 231 (to pressure P22) and compression by the boost valve 204 (to pressure P24) are performed. Therefore, the compression power in the compression section 231 is reduced by the compression work performed by the boost valve 204 compared to when compression to pressure P24 is performed only by the compression section 231. The boost valve 204 performs compression without a drive source such as a motor, and therefore the energy consumed for compression is reduced by the work performed by the boost valve 204.

[0124] [First Modification of Third Embodiment] Fig. 9 is a schematic configuration diagram showing a cooling device 201A according to a first modification of the third embodiment. The cooling device 201A is obtained by adding a booster valve to the cooling device 201 of the third embodiment shown in Fig. 8.

[0125] In the cooling device 201A according to the first modification, the boost valve 204 includes a first boost valve 311 that boosts the pressure of the raw material gas 90 compressed by the compression section 231, and a second boost valve 312 that boosts the pressure of the raw material gas 90 boosted by the first boost valve 311. In the cooling device 201A, the raw material gas 90 compressed by the compression section 231 is boosted in two stages by the first boost valve 311 and the second boost valve 312. Therefore, compared to the case where the raw material gas 90 is boosted by a single boost valve, the outlet pressure of the compression section 231 can be lowered, and the compression power of the compression section 231 can be reduced accordingly.

[0126] In the cooling device 201A according to the first modification, the gas inlet 202 receives the compressed source gas 90 from the source gas supply source 23. The pressure of the source gas 90 in the gas inlet 202 is a pressure P31. The pressure P31 is, for example, approximately 3 MPa.

[0127] The first pressure increase valve 311 is connected to the flow path 211, the flow path 213, the flow path 313, and the exhaust path 314. The first pressure increase valve 311 receives the pre-compressed source gas 90 from the gas inlet 202 via the flow path 211. The first pressure increase valve 311 receives the compressed source gas 90 from the compressor 231 via the flow path 213. The first pressure increase valve 311 compresses the source gas 90 from the compressor 231 using the expansion energy of the compressed source gas 90 from the gas inlet 202. The compressor 231 compresses the source gas 90 to a pressure P32. The first pressure increase valve 311 compresses the source gas 90 compressed to the pressure P32 to a pressure P33 (>P32). The pressure P32 is, for example, approximately 0.5 MPa. The pressure P33 is, for example, approximately 0.8 MPa.

[0128] The first pressure increase valve 311 supplies the raw material gas 90 compressed to a pressure P33 to the second pressure increase valve 312 via a flow path 313. The first pressure increase valve 311 sends the expanded raw material gas 90 to the compression section 231 via an exhaust path 314. The outlet pressure at the exhaust path 314 is, for example, approximately 0.1 MPa.

[0129] The second pressure booster valve 312 is connected to the flow path 313, the exhaust path 215, and the flow path 214. The second pressure booster valve 312 divides the source gas 90, which has been pressurized by the first pressure booster valve 311, into a first portion B1 and a second portion B2, and compresses the second portion B2 using the expansion energy of the first portion B1. The second pressure booster valve 312 compresses the second portion B2 of the source gas 90 to a pressure P34 (>P33). The pressure P34 is, for example, approximately 1.6 MPa.

[0130] The second pressure increase valve 312 sends the raw material gas 90 (second portion B2) compressed to a pressure P34 to the expansion valve 221 via the flow path 214. The second pressure increase valve 312 sends the expanded raw material gas 90 (first portion B1) to the compression section 231 via the exhaust path 215. The outlet pressure of the exhaust path 215 is, for example, approximately 0.1 MPa.

[0131] The compression unit 231 receives and compresses the raw material gas 90 supplied from the first pressure increase valve 311 via the exhaust path 314, the raw material gas 90 (first portion B1) supplied from the second pressure increase valve 312 via the exhaust path 215, and the raw material gas 90 supplied from the low-pressure side portion 236B of the circulation path 235. The compression unit 231 branches the raw material gas 90 compressed to a pressure P32 at the path 212 and sends it to the first pressure increase valve 311 and the high-pressure side portion 236A of the refrigeration cycle 203.

[0132] The other configurations of the cooling device 201A according to the first modification are similar to those of the cooling device 201 according to the third embodiment.

[0133] [Second Modification of Third Embodiment] Fig. 10 is a schematic configuration diagram showing a cooling device 201B according to a second modification of the third embodiment. In the cooling device 201B, a cooling unit 321 is added to the cooling device 201 of the third embodiment shown in Fig. 8.

[0134] The cooling device 201B according to the second modification includes a cooling unit 321 that cools the source gas 90 using a refrigerant 322. The cooling unit 321 supplies the low-temperature refrigerant 322 to the heat exchange unit 205 to cool the second portion B2 of the source gas 90 sent out from the pressure booster valve 204. In the example of FIG. 10 , the cooling unit 321 includes a refrigerant tank 323. The refrigerant tank 323 is connected to a refrigerant flow path 324. The refrigerant flow path 324 passes through a heat exchanger 325 of the heat exchange unit 205. The refrigerant 322 is not particularly limited, but may be, for example, nitrogen (liquefied nitrogen) when cooling hydrogen gas as the source gas 90. The refrigerant tank 323 stores liquefied nitrogen as the refrigerant 322 and circulates the liquefied nitrogen through the refrigerant flow path 324.

[0135] The heat exchange unit 205 includes a heat exchanger 325 in addition to the heat exchangers 206, 207, and 208. The heat exchanger 325 is disposed upstream of the heat exchanger 206. The heat exchanger 325 is disposed across the flow path 214 through which the second portion B2 discharged from the pressure booster valve 204 flows, the circulation flow path 235 (high-pressure side portion 236A and low-pressure side portion 236B), and the refrigerant flow path 324. The heat exchanger 325 pre-cools the feed gas 90 flowing through the flow path 214 and the circulation flow path 235 using the refrigerant 322 flowing through the refrigerant flow path 324. This reduces the temperature of the feed gas 90 in the refrigeration cycle 203, thereby reducing the load on the compression unit 231. The heat exchanger 325, like the heat exchangers 206, 207, and 208, includes an ortho-parallel conversion unit 240.

[0136] In this second modification, instead of providing the refrigerant tank 323 in the cooling unit 321, a refrigeration cycle using the refrigerant 322 may be provided.

[0137] The other configurations of the cooling device 201B according to the second modification are similar to those of the cooling device 201 according to the third embodiment.

[0138] [Third Modification of Third Embodiment] Fig. 11 is a schematic configuration diagram showing a cooling device 201C according to a third modification of the third embodiment. In the cooling device 201 of the third embodiment shown in Fig. 8, the high-pressure side portion 236A of the circulation flow path 235 is branched into two, and the first expansion section 233 and the second expansion section 234 are provided in parallel, forming a parallel two-stage cycle. However, in the cooling device 201C shown in Fig. 11, the high-pressure side portion 236A of the circulation flow path 235 is a flow path without branching, and the first expansion section 233 and the second expansion section 234 are provided in series, forming a serial two-stage cycle.

[0139] In the cooling device 201C according to the third modification, the high-pressure side portion 236A of the circulation flow path 235 is composed of a first flow path 331 that connects the compression section 231 and the second expansion section 234, and a second flow path 332 that connects the second expansion section 234 and the first expansion section 233. Therefore, the high-pressure side portion 236A connects the second expansion section 234 and the first expansion section 233 in series without branching.

[0140] A heat exchanger 206 is disposed in the first flow path 331. High-pressure raw material gas 90 branching from the flow path 212 and flowing into the refrigeration cycle 203 (first flow path 331) is cooled in the heat exchanger 206 and then supplied to the second expansion section 234. The second expansion section 234 performs a first-stage expansion of the raw material gas 90 received from the first flow path 331. The second expansion section 234 supplies the raw material gas 90, whose temperature has been reduced by the expansion, to the first expansion section 233 via the second flow path 332.

[0141] A heat exchanger 208 is disposed in the second flow path 332. The medium-pressure raw material gas 90 flowing from the second expansion section 234 into the second flow path 332 is cooled in the heat exchanger 208 and then supplied to the first expansion section 233. The first expansion section 233 performs a second-stage expansion on the raw material gas 90 received from the second flow path 332. The first expansion section 233 sends the raw material gas 90, whose temperature has been reduced by the expansion, to the low-pressure side portion 236B of the circulation flow path 235.

[0142] In the cooling device 201C according to the third modification, the second expansion section 234 and the first expansion section 233 are arranged in series, and since there is no need to merge the raw material gas 90 from the second expansion section 234 into the low-pressure side section 236B, the heat exchanger 207 and the connection path 239 are not provided. The heat exchange section 205 includes two heat exchangers, a heat exchanger 206 and a heat exchanger 208. The low-temperature, low-pressure raw material gas 90 flowing from the first expansion section 233 into the low-pressure side section 236B is returned to the compression section 231 after the heat exchangers 208 and 206 are added in sequence to cool the raw material gas 90 flowing through the high-pressure side section 236A and the raw material gas 90 flowing through the flow path 214 (second portion B2).

[0143] The other configurations of the cooling device 201B according to the third modification are similar to those of the cooling device 201 according to the third embodiment.

[0144] [Fourth Modification of Third Embodiment] Fig. 12 is a schematic diagram showing a cooling device 201D according to a fourth modification of the third embodiment. In the cooling device 201C shown in Fig. 11, the refrigeration cycle 203 is a two-stage series cycle in which the first expansion section 233 and the second expansion section 234 are provided in series in the circulation flow path 235. However, in the cooling device 201D according to the fourth modification, the refrigeration cycle 203 has only one expansion section, and the raw material gas 90 is pre-cooled by a cooling section 321 using a refrigerant 322.

[0145] In a cooling device 201D according to the fourth modification, a refrigeration cycle 203 includes a single-stage expansion section 232. The expansion section receives and expands high-pressure source gas 90 from a high-pressure side section 236A of a circulation flow path 235, and sends the source gas 90, whose temperature has been reduced by the expansion, to a low-pressure side section 236B.

[0146] The cooling device 201D includes a cooling section 321 that cools the source gas 90 using a refrigerant 322. The configuration of the cooling section 321 is the same as that of the second modified example.

[0147] The heat exchange section 205 includes a heat exchanger 208 and a heat exchanger 325. The heat exchanger 208 cools the raw material gas 90 flowing through the high-pressure side section 236A and the raw material gas 90 (second portion B2) sent from the pressure boost valve 204 to the flow path 214, using the low-temperature, low-pressure raw material gas 90 sent from the single-stage expansion section 232 to the low-pressure side section 236B.

[0148] The heat exchanger 325 is disposed in a stage preceding the heat exchanger 208. The heat exchanger 325 pre-cools the raw material gas 90 flowing through the flow path 214 and the circulation flow path 235 by the refrigerant 322 flowing through the refrigerant flow path 324.

[0149] In this fourth modification, similarly to the second modification, instead of providing the refrigerant tank 323 in the cooling unit 321, a refrigeration cycle using the refrigerant 322 may be provided.

[0150] The other configurations of the cooling device 201D according to the fourth modification are similar to those of the cooling device 201 according to the third embodiment.

[0151] [Fifth Modification of Third Embodiment] Fig. 13 is a schematic diagram showing a cooling device 201E according to a fifth modification of the third embodiment. In the cooling device 201E according to the fifth modification, the expansion section 232 of the fourth modification shown in Fig. 12 is changed from a single stage to a two-stage series configuration of a first expansion section 233 and a second expansion section 234.

[0152] In the cooling device 201E according to the fifth modification, the high-pressure side portion 236A of the circulation flow path 235 is composed of a first flow path 331 connecting the compression section 231 and the second expansion section 234, and a second flow path 332 connecting the second expansion section 234 and the first expansion section 233. Therefore, the high-pressure side portion 236A connects the second expansion section 234 and the first expansion section 233 in series without branching. The configuration of the expansion section 232 is the same as that of the third modification shown in FIG. 11 .

[0153] The high-pressure feed gas 90 sent from the compression section 231 to the high-pressure side section 236A of the refrigeration cycle 203 is pre-cooled by the refrigerant 322 in the cooling section 321 in the heat exchanger 325, then cooled in the heat exchanger 206, and supplied to the second expansion section 234. The medium-pressure feed gas 90 expanded and lowered in temperature in the second expansion section 234 is cooled in the heat exchanger 208 and supplied to the first expansion section 233. The low-pressure feed gas 90 expanded and lowered in temperature in the first expansion section 233 is sent to the low-pressure side section 236B of the refrigeration cycle 203. The low-temperature, low-pressure feed gas 90 flowing from the first expansion section 233 into the low-pressure side section 236B passes through the heat exchanger 208 and the heat exchanger 206 in this order, where the feed gas 90 flowing through the high-pressure side section 236A and the feed gas 90 (second section B2) flowing through the flow path 214 are cooled, and then returned to the compression section 231.

[0154] The other configurations of the cooling device 201E according to the fifth modified example are similar to those of the cooling device 201D according to the fourth modified example.

[0155] 14 is a schematic diagram showing a cooling device 201F according to a sixth modification of the third embodiment. Unlike the cooling device 201 of the third embodiment, which is based on the Brayton cycle, the cooling device 201F is based on the Claude cycle.

[0156] In a cooling device 201F according to the sixth modification, a booster valve 204 is incorporated into a part of a refrigeration cycle 203. A compression section 231 and the booster valve 204 are connected in series by a flow path 341 without any branching. A circulation flow path 235 of the refrigeration cycle 203 is provided with the compression section 231, the booster valve 204, an expansion section 232, an expansion valve 221, and a liquid tank 222. A heat exchanger 205 is also disposed in the circulation flow path 235. The heat exchanger 205 includes heat exchangers 206, 207, and 208.

[0157] The circulation flow path 235 includes a flow path 341 connecting the compression section 231 and the boost valve 204, a branched flow path 342 connecting the boost valve 204 with the expansion section 232 and the expansion valve 221, a flow path 343 connecting the expansion valve 221 with the liquid tank 222, and a return flow path 344 connecting the liquid tank 222 with the compression section 231.

[0158] A flow path 345 extending from the gas inlet section 202 is connected to the return flow path 344. The raw material gas 90 received by the gas inlet section 202 is a non-compressed gas that has not been compressed in advance. The flow path 345 is connected to the return flow path 344 at a position between the compression section 231 and the heat exchanger 206. The raw material gas 90 supplied to the gas inlet section 202 is merged with the raw material gas 90 flowing through the return flow path 344, and is supplied to the compression section 231.

[0159] The compression unit 231 receives the low-pressure raw material gas 90 from the return flow path 344, compresses it, and sends the high-pressure raw material gas 90 to the flow path 341. The compression unit 231 supplies all of the compressed raw material gas 90 to the pressure boost valve 204. The pressure P41 at the outlet of the compression unit 231 is, for example, approximately 0.8 MPa.

[0160] The boost valve 204 is connected to the exhaust path 346 in addition to the flow paths 341 and 342. The boost valve 204 receives the medium-pressure source gas 90 from the compression unit 231 via the flow path 341. The boost valve 204 compresses the second portion B2 of the source gas 90 using the expansion energy of the first portion B1 of the received source gas 90. The boost valve 204 delivers the compressed, high-pressure second portion B2 to the flow path 342. The pressure P42 of the second portion B2 at the outlet of the boost valve 204 is, for example, approximately 1.6 MPa. The boost valve 204 delivers the expanded, low-pressure first portion B1 to the exhaust path 346. As a result, the boost valve 204 delivers the expanded first portion B1 to the compression unit 231. The pressure P43 of the first portion B1 at the outlet of the boost valve 204 is, for example, approximately 0.1 MPa.

[0161] Flow path 342 branches into a high-pressure flow path 237 and a high-pressure flow path 238 at a branching point between heat exchangers 206 and 207. High-pressure flow path 237 passes through heat exchangers 207 and 208 and connects to expansion valve 221. High-pressure flow path 238 connects directly from the branching point (without passing through a heat exchanger) to expansion section 232. Therefore, a part C1 of second portion B2 of source gas 90 pressurized by pressure booster valve 204 is supplied to expansion section 232, and the remaining part C2 of second portion B2 passes through heat exchangers 207 and 208 and is supplied to expansion valve 221.

[0162] The expansion section 232 receives the medium-pressure source gas 90 (second portion B2) via the high-pressure flow path 238. The expansion section 232 expands a part C1 of the second portion B2 of the source gas 90 whose pressure has been increased by the pressure increase valve 204. The outlet pressure of the expansion section 232 is, for example, approximately 0.1 MPa. The expansion section 232 expands the source gas 90 received from the high-pressure flow path 238 to lower its temperature, and sends it out to the connection path 239. The connection path 239 is connected to the return flow path 344 at a connection position between the heat exchanger 207 and the heat exchanger 208.

[0163] Therefore, a portion C1 of the low-temperature, low-pressure second portion B2, which has been expanded and cooled by the expansion section 232, passes through the connecting path 239 and is sent to the return path 344, and then passes through the heat exchanger 207. In the heat exchanger 207, the portion C1 of the second portion B2 of the source gas 90, which has been pressurized by the pressure booster valve 204 and sent to the high-pressure path 238, cools the remainder C2 sent to the high-pressure path 237. In this way, the heat exchange section 205 cools the remainder C2 of the second portion B2 by the portion C1 of the second portion B2 expanded by the expansion section 232.

[0164] The expansion valve 221 receives the low-temperature, medium-pressure raw material gas 90 (the remaining portion C2 of the second portion B2) cooled in the heat exchanger 205 via the high-pressure flow path 237. The expansion valve 221 expands the second portion B2 cooled in the heat exchanger 205 to liquefy at least a portion of the second portion B2. The outlet pressure of the expansion valve 221 is, for example, approximately 0.1 MPa. The second portion B2 that has passed through the expansion valve 221 is stored in a gas-liquid mixed phase state in the liquid tank 222.

[0165] The return gas, which includes the gas-phase raw material gas 90 that has flowed into the liquid tank 222 and the raw material gas 90 generated (vaporized) in the liquid tank 222, flows through the return flow path 344 and cools the raw material gas 90 (the remaining portion C2 of the second portion B2) in the high-pressure flow path 237 in the heat exchanger 208, and then merges with the raw material gas 90 from the expansion section 232 at the connection position with the connection path 239. The merged return gas passes through the heat exchanger 207 to cool the raw material gas 90 (the remaining portion C2 of the second portion B2) in the high-pressure flow path 237, and passes through the heat exchanger 206 to cool the raw material gas 90 (the second portion B2) in the flow path 342. The return gas that has passed through the heat exchanger 206 is merged with the raw material gas 90 from the flow path 345 and is supplied to the compression section 231.

[0166] The other configurations of the cooling device 201F according to the sixth modification are similar to those of the cooling device 201 according to the third embodiment.

[0167] 15 is a schematic configuration diagram illustrating a cooling device 201G according to a seventh modification of the third embodiment. The cooling device 201G is obtained by adding a cooling unit 321 to the cooling device 201F according to the sixth modification of the third embodiment shown in FIG.

[0168] The cooling device 201G according to the seventh modification includes a cooling unit 321 that cools the source gas 90 using a refrigerant 322. The cooling unit 321 supplies the low-temperature refrigerant 322 to the heat exchange unit 205, and cools the second portion B2 of the source gas 90 sent out from the pressure increase valve 204. The configuration of the cooling unit 321 is similar to that of the second modification shown in FIG.

[0169] The heat exchange unit 205 includes a heat exchanger 325 in addition to the heat exchangers 206, 207, and 208. The heat exchanger 325 is disposed in a stage preceding the heat exchanger 206. The heat exchanger 325 is disposed across a flow path 342, through which the second portion B2 delivered from the pressure increase valve 204 flows, and a return flow path 344. The heat exchanger 325 pre-cools the raw material gas 90 flowing through the flow path 342 and the return flow path 344, by the refrigerant 322 flowing through the refrigerant flow path 324. This can lower the temperature of the raw material gas 90 in the refrigeration cycle 203, thereby reducing the load on the compression unit 231.

[0170] In this seventh modification, instead of providing the refrigerant tank 323 in the cooling unit 321, a refrigeration cycle using the refrigerant 322 may be provided.

[0171] The other configurations of the cooling device 201G according to the seventh modified example are similar to those of the cooling device 201F according to the sixth modified example.

[0172] [Action and effect of this embodiment] The cooling device according to the first aspect includes a gas inlet section 2 that receives compressed raw material gas 90 from a raw material gas supply source 23, a first expansion section 3 that expands a first portion 91 of the raw material gas 90, a first heat exchange section 5 that cools a second portion 92 of the raw material gas 90 using the first portion 91 whose temperature has been reduced by expansion, and a compression section 8 that compresses the first portion 91 whose temperature has been increased by heat exchange and merges it with the raw material gas 90 received from the gas inlet section 2.

[0173] According to the cooling device of the first aspect, the pre-compressed source gas 90 is divided into a first portion 91 and a second portion 92, and the second portion 92 is cooled by the first portion 91, whose temperature has been reduced by expansion. The first portion 91, whose temperature has been increased by heat exchange, is compressed by the compression unit 8 and merged with the source gas 90 received from the gas inlet unit 2. Therefore, the compression unit 8 only needs to compress a portion of the source gas 90 received from the gas inlet unit 2. Therefore, the compression power required to cool the source gas 90 can be reduced compared to when uncompressed (low-pressure) source gas 90 is received from the source gas supply source 23 and the entire amount of the received source gas 90 is compressed.

[0174] The cooling device according to the second aspect is the cooling device according to the first aspect, further comprising a second expansion section 4 provided upstream of the first expansion section 3. The first expansion section 3 further expands a first portion 91 of the source gas 90 after expansion by the second expansion section 4, and the first heat exchange section 5 cools a second portion 92 of the source gas 90 after expansion by the second expansion section 4 using the first portion 91. This allows the pre-compressed source gas 90 to be expanded in two stages by the second expansion section 4 and the first expansion section 3, thereby generating a low-temperature, low-pressure first portion 91. By cooling the second portion 92 using the generated low-temperature, low-pressure first portion 91, the cooling performance of the source gas 90 (second portion 92) can be improved.

[0175] The cooling device according to the third aspect is the cooling device according to the second aspect, further comprising a second heat exchange section 6 that cools the raw material gas 90 before expansion by the second expansion section 4 using a second portion 92 of the raw material gas 90 after expansion by the second expansion section 4, and the first heat exchange section 5 cools the second portion 92 that has passed through the second heat exchange section 6 using the first portion 91 expanded by the first expansion section 3. This makes it possible to improve the cooling performance of the raw material gas 90 (second portion 92) through two-stage heat exchange by the first heat exchange section 5 and the second heat exchange section 6.

[0176] A cooling device according to a fourth aspect is the cooling device according to any one of the first to third aspects, further including an expansion valve 21 that expands the second portion 92 cooled by the first heat exchanger 5 to liquefy at least a portion of the second portion 92. This allows the expansion valve 21 to liquefy the raw material gas 90. Because a large amount of compression power is required to liquefy a low-boiling-point gas such as hydrogen, the cooling device according to this aspect is particularly effective in reducing the compression power required to cool the raw material gas 90.

[0177] The cooling device according to a fifth aspect is the cooling device according to any one of the first to fourth aspects, further including a third heat exchanger 7 that cools the source gas 90 with the refrigerant 35. This improves the cooling effect of the source gas 90 through heat exchange with the refrigerant 35 in the third heat exchanger 7. As a result, the cooling using the refrigerant 35 reduces the compression power required to achieve a desired cooling effect on the source gas 90.

[0178] A cooling apparatus according to a sixth aspect is the cooling apparatus according to any one of the first to fifth aspects, further comprising a raw material gas generator 50 that generates a raw material gas 90 from a raw material liquid and supplies the generated raw material gas 90 to the gas inlet 2. The raw material gas generator 50 has a raw material gas generation unit 53 and a pressurization unit 52 that compresses the raw material gas 90 by pressurizing and supplying the raw material liquid 95 to the raw material gas generation unit 53. As a result, when generating the raw material gas 90 from the raw material liquid 95, the compressed raw material gas 90 can be obtained by the pressurized supply of the raw material liquid 95 by the pressurization unit 52. The pressurization unit 52 can be configured with a liquid pump or the like for pressurizing and supplying the raw material liquid 95. This reduces the power required to obtain the pre-compressed raw material gas 90 compared to compressing the gas-phase raw material gas 90 using a compression turbine or the like.

[0179] The cooling method according to the seventh aspect includes the steps of receiving compressed raw material gas 90 from a raw material gas supply source 23, expanding a first portion 91 of the raw material gas 90, cooling a second portion 92 of the raw material gas 90 using the first portion 91 whose temperature has been reduced by the expansion, and compressing the first portion 91 whose temperature has been increased and merging it with the raw material gas 90 received from the raw material gas supply source 23.

[0180] According to the cooling method of the seventh aspect, the pre-compressed source gas 90 is divided into a first portion 91 and a second portion 92, and the second portion 92 is cooled by the first portion 91, whose temperature has been reduced by expansion. The first portion 91, whose temperature has been increased by heat exchange, is compressed and merged with the source gas 90 received from the source gas supply source 23. Therefore, it is sufficient to compress only a portion of the received source gas 90. Therefore, the compression power required to cool the source gas 90 can be reduced compared to when uncompressed (low-pressure) source gas 90 is received from the source gas supply source 23 and the entire amount of the received source gas 90 is compressed.

[0181] The cooling device according to the eighth aspect includes a gas inlet section 102 that receives compressed raw material gas 90 from a raw material gas supply source 23, a refrigeration cycle 103 that has a compression section 121 and an expansion section 123 and circulates a refrigerant 191, a heat exchange section 104 that cools the raw material gas 90 with the refrigerant 191 of the refrigeration cycle 103, and an auxiliary expansion section 105 that expands the raw material gas 90 to assist the compression power of the compression section 121 of the refrigeration cycle 103.

[0182] According to the cooling device of the eighth aspect, in the cooling device 101 that has the compression section 121 and the expansion section 123 and cools the feed gas 90 by the refrigeration cycle 103 that circulates the refrigerant 191, the compression power of the compression section 121 can be reduced by the amount of power obtained by expanding the pre-compressed feed gas 90. Therefore, the compression power for cooling the feed gas 90 can be reduced compared to when uncompressed (low-pressure) feed gas 90 is received from the feed gas supply source 23 and the refrigerant 191 is compressed without power assistance by the auxiliary expansion section 105.

[0183] A cooling device according to a ninth aspect is the cooling device according to the eighth aspect, in which the auxiliary expansion section 105 expands the raw material gas 90 that has been cooled by passing from the gas inlet section 102 through the heat exchange section 104, thereby assisting the compression power of the compression section 121 and liquefying at least a portion of the raw material gas 90 by lowering the temperature of the raw material gas 90. As a result, the expansion of the raw material gas 90 by the auxiliary expansion section 105 not only assists the compression power of the compression section 121, but also liquefies the raw material gas 90.

[0184] A cooling device according to a tenth aspect is the cooling device according to the eighth aspect, in which the auxiliary expansion section 105 expands the raw material gas 90 received from the gas inlet section 102 to assist the compression power of the compression section 121 and also lowers the temperature of the raw material gas 90 before sending it to the heat exchange section 104. In this way, the expansion of the raw material gas 90 by the auxiliary expansion section 105 not only assists the compression power of the compression section 121 but also enables pre-cooling of the raw material gas 90 before cooling of the raw material gas 90 by the heat exchange section 104.

[0185] A cooling device according to an eleventh aspect is the cooling device according to any one of the eighth to tenth aspects, in which the compression section 121 includes a compression turbine 127 that compresses the refrigerant 191 by rotation, and the auxiliary expansion section 105 includes an expansion turbine 113 connected to the compression turbine 127. This allows the compression power of the compression turbine 127 to be directly assisted by the rotational power recovered by the expansion of the raw material gas 90 in the expansion turbine 113. Therefore, the auxiliary expansion section 105 can perform power assist with high energy efficiency.

[0186] A cooling apparatus according to a twelfth aspect is the cooling apparatus according to any one of the eighth to eleventh aspects, further comprising a raw material gas generator 50 that generates a raw material gas 90 from a raw material liquid 95 and supplies the generated raw material gas 90 to a gas inlet 102. The raw material gas generator 50 has a raw material gas generation unit 53 and a pressurization unit 52 that compresses the raw material gas 90 by pressurizing and supplying the raw material liquid 95 to the raw material gas generation unit 53. As a result, when generating the raw material gas 90 from the raw material liquid 95, the compressed raw material gas 90 can be obtained by pressurizing and supplying the raw material liquid 95 by the pressurization unit 52. The pressurization unit 52 can be configured with a liquid pump or the like for pressurizing and supplying the raw material liquid 95. This reduces the power required to obtain the pre-compressed raw material gas 90 compared to compressing the gas-phase raw material gas 90 using a compression turbine or the like.

[0187] The cooling method according to the thirteenth aspect includes the steps of receiving compressed raw material gas 90 from a raw material gas supply source 23, cooling the raw material gas 90 with a refrigerant 191 of a refrigeration cycle 103 having a compression section 121 and an expansion section 123 and circulating the refrigerant 191, and expanding the raw material gas 90 to assist the compression power of the compression section 121 of the refrigeration cycle 103.

[0188] According to the cooling method of the thirteenth aspect, when the feed gas 90 is cooled by the refrigeration cycle 103 having the compression section 121 and the expansion section 123 and circulating the refrigerant 191, the compression power of the compression section 121 can be reduced by the power obtained by the expansion of the pre-compressed feed gas 90. Therefore, the compression power for cooling the feed gas 90 can be reduced compared to when the uncompressed (low-pressure) feed gas 90 is received from the feed gas supply source 23 and the refrigerant 191 is compressed without the power assistance of the expansion of the feed gas 90.

[0189] The cooling device according to the fourteenth aspect includes a refrigeration cycle 203 having a gas inlet section 202 that receives a raw material gas 90 from a raw material gas supply source 23, a compression section 231 that compresses the raw material gas 90, and an expansion section 232 that expands the compressed raw material gas 90, a boost valve 204 that compresses a second portion B2 of the raw material gas 90 using expansion energy of a first portion B1 of the raw material gas 90 and sends the expanded first portion B1 to the compression section 231, and a heat exchange section 205 that cools the second portion B2 compressed by the boost valve 204 with the raw material gas 90 circulating through the refrigeration cycle 203.

[0190] According to the cooling device of the fourteenth aspect, the raw material gas 90 can be compressed in multiple stages, including compression by the compression unit 231 and compression by the boost valve 204. The boost valve 204 compresses the second portion B2 of the raw material gas 90 using the expansion energy of the first portion B1, so compression can be performed without external power. Therefore, the compression work by the compression unit 231 can be reduced by the amount of compression work by the boost valve 204. Therefore, the compression power required to cool the raw material gas 90 can be reduced compared to when the raw material gas 90 is compressed to a desired pressure only by the compression unit 231 without using the boost valve 204.

[0191] A cooling device according to a fifteenth aspect is the cooling device according to the fourteenth aspect, wherein the boost valve 204 compresses the second portion B2 of the source gas 90 compressed to a predetermined pressure P22 by the compression unit 231 using the first portion B1, and the compression unit 231 recompresses the first portion B1 expanded by the boost valve 204 to the predetermined pressure P22 and supplies the recompressed first portion B1 to the boost valve 204. This allows the first portion B1 used to compress the second portion B2 in the boost valve 204 to be recompressed by the compression unit 231 and circulated and supplied to the boost valve 204. This prevents loss of the source gas 90 due to compression of the source gas 90 (second portion B2) by the boost valve 204.

[0192] A cooling device according to a sixteenth aspect is the cooling device according to the fourteenth or fifteenth aspect, wherein the boost valve 204 includes a first boost valve 311 that boosts the pressure of the raw material gas 90 compressed by the compression section 231, and a second boost valve 312 that boosts the pressure of the raw material gas 90 boosted by the first boost valve 311. This allows the raw material gas 90 to be compressed in multiple stages by the first boost valve 311 and the second boost valve 312, thereby further reducing the compression work by the compression section 231.

[0193] A cooling device according to a seventeenth aspect is the cooling device according to any one of the fourteenth to sixteenth aspects, in which the compression section 231 supplies a portion of the compressed raw material gas 90 to the boost valve 204, and circulates the remainder of the compressed raw material gas 90 in the refrigeration cycle 203. This makes it possible to separately construct a path for circulating a portion of the raw material gas 90 toward the boost valve 204, and a path for circulating the remainder of the raw material gas 90 in the refrigeration cycle 203. This makes it easy to optimize the flow conditions, such as the flow rate of the raw material gas 90, in each path.

[0194] The cooling device according to an eighteenth aspect is the cooling device according to any one of the fourteenth to sixteenth aspects, in which the compression section 231 supplies all of the compressed source gas 90 to the pressure booster valve 204, the expansion section 232 expands a portion C1 of the second portion B2 of the source gas 90 pressurized by the pressure booster valve 204, and the heat exchange section 205 cools the remaining portion C2 of the second portion B2 using the portion C1 of the second portion B2 expanded by the expansion section 232. This allows the remaining portion C2 of the second portion B2 to be effectively cooled by the portion C1 of the second portion B2 whose temperature has been reduced by the expansion. As a result, the cooling performance of the cooling device 201 can be improved.

[0195] A cooling device according to a nineteenth aspect is the cooling device according to any one of the fourteenth to eighteenth aspects, further including an expansion valve 221 that expands the second portion B2 cooled by the heat exchanger 205 to liquefy at least a portion of the second portion B2. This allows the expansion valve 221 to liquefy the raw material gas 90. Because a large amount of compression power is required to liquefy a low-boiling-point gas such as hydrogen, the cooling device 201 according to this aspect is particularly effective in reducing the compression power required to cool the raw material gas 90.

[0196] The cooling method according to the twentieth aspect includes the steps of receiving a raw material gas 90 from a raw material gas supply source 23, compressing a second portion B2 of the raw material gas 90 by a boost valve 204 using expansion energy of a first portion B1 of the raw material gas 90, cooling the second portion B2 compressed by the boost valve 204 by the raw material gas 90 circulating through a refrigeration cycle 203 having a compression section 231 that compresses the raw material gas 90 and an expansion section 232 that expands the compressed raw material gas 90, and compressing the first portion B1 expanded by the boost valve 204 by the compression section 231.

[0197] According to the cooling method of the twentieth aspect, the raw material gas 90 can be compressed in a multi-stage manner, including compression by the compression unit 231 and compression by the boost valve 204. The boost valve 204 compresses the second portion B2 of the raw material gas 90 using the expansion energy of the first portion B1, and therefore compression can be performed without external power. Therefore, the compression work by the compression unit 231 can be reduced by the amount of compression work by the boost valve 204. Therefore, the compression power required to cool the raw material gas 90 can be reduced compared to when the raw material gas 90 is compressed to a desired pressure only by the compression unit 231 without using the boost valve 204.

[0198] DESCRIPTION OF SYMBOLS 1, 1A, 1B, 101, 101A, 201, 201A, 201B, 201C, 201D, 201E, 201F, 201G Cooling device 2, 102, 202 Gas introduction section 3 First expansion section 4 Second expansion section 5 First heat exchange section 6 Second heat exchange section 7 Third heat exchange section 8 Compression section 21 Expansion valve 23 Raw material gas supply source 35 Refrigerant 50 Raw material gas generation device 52 Pressurization section 53 Raw material gas generation section 90 Raw material gas 91 First section 92 Second section 95 Raw material liquid 103, 203 Refrigeration cycle 104, 205 Heat exchange section 105 Auxiliary expansion section 113 Expansion turbine 121 Compression section 123 Expansion section 127 Compression turbine 191 Refrigerant 204 Booster valve 221 Expansion valve 231 Compression section 232 Expansion section 311 First booster valve 312 Second booster valve B1 First section B2 Second section C1 Part C2 Remaining section

Claims

1. A cooling device comprising: a gas introduction part that receives a compressed raw material gas from a raw material gas supply source; a first expansion part that expands a first part of the raw material gas; a first heat exchange part that cools a second part of the raw material gas with the first part whose temperature has been lowered by expansion; and a compression part that compresses the first part whose temperature has been raised by heat exchange and merges it with the raw material gas received from the gas introduction part.

2. The cooling device according to claim 1, further comprising a second expansion part provided upstream of the first expansion part, wherein the first expansion part further expands the first part of the raw material gas after expansion by the second expansion part, and the first heat exchange part cools the second part of the raw material gas after expansion by the second expansion part with the first part.

3. The cooling device according to claim 2, further comprising a second heat exchange part that cools the raw material gas before expansion by the second expansion part with the second part of the raw material gas after expansion by the second expansion part, and the first heat exchange part cools the second part that has passed through the second heat exchange part with the first part expanded by the first expansion part.

4. The cooling device according to any one of claims 1 to 3, further comprising an expansion valve that expands the second part cooled by the first heat exchange part to liquefy at least a part of the second part.

5. The cooling device according to any one of claims 1 to 3, further comprising a third heat exchange part that cools the raw material gas with a refrigerant.

6. The cooling device according to any one of claims 1 to 3, further comprising a raw material gas generation device that generates the raw material gas from a raw material liquid and supplies the generated raw material gas to the gas introduction part, wherein the raw material gas generation device has a raw material gas generation part and a pressurization part that compresses the raw material gas by pressurizing and supplying the raw material liquid to the raw material gas generation part.

7. A cooling method comprising: receiving a compressed raw material gas from a raw material gas supply source; expanding a first part of the raw material gas; cooling a second part of the raw material gas with the first part whose temperature has been lowered by expansion; and compressing the first part whose temperature has been raised and merging it with the raw material gas received from the raw material gas supply source.

8. A cooling device comprising: a gas introduction part that receives the compressed raw material gas from a raw material gas supply source; a refrigeration cycle having a compression part and an expansion part and circulating a refrigerant; a heat exchange part that cools the raw material gas with the refrigerant of the refrigeration cycle; and an auxiliary expansion part that assists the compression power of the compression part of the refrigeration cycle by expanding the raw material gas.

9. The cooling device according to claim 8, wherein the auxiliary expansion part assists the compression power of the compression part by expanding the raw material gas that has passed through the heat exchange part and been cooled after passing through the gas introduction part, and liquefies at least a part of the raw material gas by lowering the temperature of the raw material gas.

10. The cooling device according to claim 8, wherein the auxiliary expansion part assists the compression power of the compression part by expanding the raw material gas received from the gas introduction part, and sends the raw material gas with a lowered temperature to the heat exchange part.

11. The cooling device according to any one of claims 8 to 10, wherein the compression part includes a compression turbine that compresses the refrigerant by rotation, and the auxiliary expansion part includes an expansion turbine connected to the compression turbine.

12. The cooling device according to any one of claims 8 to 10, further comprising a raw material gas generation device that generates the raw material gas from a raw material liquid and supplies the generated raw material gas to the gas introduction part, wherein the raw material gas generation device has a raw material gas generation part and a pressurization part that compresses the raw material gas by pressurizing and supplying the raw material liquid to the raw material gas generation part.

13. A cooling method comprising: receiving a compressed raw material gas from a raw material gas supply source; cooling the raw material gas with the refrigerant of a refrigeration cycle having a compression part and an expansion part and circulating the refrigerant; and assisting the compression power of the compression part of the refrigeration cycle by expanding the raw material gas.

14. A cooling device comprising: a gas introduction unit that receives a raw material gas from a raw material gas supply source; a compression unit that compresses the raw material gas; an expansion unit that expands the compressed raw material gas; a refrigeration cycle; a booster valve that compresses a second portion of the raw material gas by the expansion energy of a first portion of the raw material gas and sends the expanded first portion to the compression unit; and a heat exchange unit that cools the second portion compressed by the booster valve with the raw material gas flowing through the refrigeration cycle.

15. The cooling device according to claim 14, wherein the booster valve compresses the second portion by the first portion among the raw material gas compressed to a predetermined pressure by the compression unit, and the compression unit recompresses the first portion expanded by the booster valve to the predetermined pressure and supplies it to the booster valve.

16. The cooling device according to claim 14, wherein the booster valve includes a first booster valve that boosts the raw material gas compressed by the compression unit and a second booster valve that boosts the raw material gas boosted by the first booster valve.

17. The cooling device according to claim 14, wherein the compression unit supplies a part of the compressed raw material gas to the booster valve and circulates the remaining part of the compressed raw material gas in the refrigeration cycle.

18. The cooling device according to claim 14, wherein the compression unit supplies all of the compressed raw material gas to the booster valve, the expansion unit expands a part of the second portion of the raw material gas boosted by the booster valve, and the heat exchange unit cools the remaining part of the second portion with a part of the second portion expanded by the expansion unit.

19. The cooling device according to any one of claims 14 to 18, further comprising an expansion valve that expands the second portion cooled by the heat exchange unit to liquefy at least a part of the second portion.

20. A cooling method comprising: receiving a raw material gas from a raw material gas supply source; compressing a second portion of the raw material gas by the expansion energy of a first portion of the raw material gas by a booster valve; cooling the second portion compressed by the booster valve with the raw material gas flowing through a refrigeration cycle having a compression unit that compresses the raw material gas and an expansion unit that expands the compressed raw material gas; and compressing the first portion expanded by the booster valve by the compression unit.

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