Liquefaction device and liquefaction method

Abstract

To improve liquefaction efficiency of raw material gas.SOLUTION: A liquefaction device comprises: a raw material pipe through which raw material gas flows; a raw material cooling part for cooling the raw material gas flowing through the raw material pipe, by a refrigerant; a magnetic refrigeration part provided on the downstream side of the raw material cooling part in the flow of the raw material gas in the raw material pipe, and for cooling the cooled raw material gas by a magnetic body to liquefy the raw material gas; and a magnetic body cooling part for cooling the magnetic body having cooled the raw material gas, by the refrigerant.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a liquefaction device and a liquefaction method. [Background technology]

[0002] There are known techniques for liquefying and storing raw material gases such as hydrogen gas. For example, Non-Patent Document 1 describes that raw material hydrogen gas is liquefied by cooling it with liquid nitrogen and expanding it with a Joule-Thomson valve. [Prior art documents] [Patent documents]

[0003] [Non-Patent Document 1] Seiji Yamashita et al., "Development of Hydrogen Liquefaction Storage System," Journal of Japan Society of Energy and Resources, Vol. 37, No. 4 Summary of the Invention [Problem to be solved by the invention]

[0004] However, since the liquefaction of gas using a Joule-Thomson valve utilizes the principle of isenthalpic expansion, there is a risk of low liquefaction efficiency. Therefore, there is a demand for improving the liquefaction efficiency of the raw gas.

[0005] An object of the present disclosure is to provide a liquefaction apparatus and a liquefaction method capable of improving the efficiency of liquefying a raw material gas. [Means for solving the problem]

[0006] The liquefaction apparatus according to the present disclosure comprises a raw material piping through which a raw material gas flows, a raw material cooling unit that cools the raw material gas flowing through the raw material piping with a refrigerant, a magnetic refrigeration unit that is provided downstream of the flow of the raw material gas within the raw material piping from the raw material cooling unit and cools the cooled raw material gas with a magnetic material to liquefy the raw material gas, and a magnetic material cooling unit that cools the magnetic material that has cooled the raw material gas with the refrigerant.

[0007] The liquefaction method according to the present disclosure includes the steps of cooling a raw gas with a refrigerant, cooling the raw gas cooled by the refrigerant with a magnetic material to liquefy the raw gas, and cooling the magnetic material that has cooled the raw gas with the refrigerant. Effect of the Invention

[0008] According to the present disclosure, the efficiency of liquefying a raw material gas can be improved. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a liquefaction device according to the present embodiment. [Diagram 2] FIG. 2 is a schematic diagram illustrating an example of a refrigeration cycle of the magnetic refrigeration unit. [Diagram 3] FIG. 3 is a flow chart illustrating the method for liquefying a raw material gas. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Note that the present disclosure is not limited to these embodiments, and when there are multiple embodiments, the present disclosure also includes combinations of the embodiments.

[0011] (liquefier) FIG. 1 is a schematic diagram of a liquefaction apparatus according to this embodiment. The liquefaction apparatus 1 according to this embodiment is an apparatus for liquefying a raw material gas HG. Hereinafter, the liquefied raw material gas HG will be referred to as liquid HL. The raw material gas HG may be any substance, such as hydrogen, oxygen, or natural gas, but in this embodiment, hydrogen is used as the raw material gas HG. Therefore, the liquid HL in this embodiment is liquid hydrogen. In addition, the raw material gas HG and the liquid HL may be used for any purpose, such as rocket fuel.

[0012] As shown in FIG. 1, the liquefaction apparatus 1 has a raw material piping 10, a raw material supply section 12, a liquid storage section 14, nitrogen pipes 20, 22, a nitrogen supply section 24, a refrigerant piping 30, a refrigerant compression section 32, a refrigerant cooling section 34, refrigerant expansion sections 36, 38, a raw material cooling section 40, a raw material expansion section 48, a magnetic refrigeration section 50, a magnetic material cooling section 60, and a control device 100.

[0013] The control device 100 is a controller that controls each mechanism of the liquefaction apparatus 1. The control device 100 controls each mechanism of the liquefaction apparatus 1, whereby the raw material gas HG is liquefied by the liquefaction apparatus 1 to produce a liquid HL. The control device 100 may be, for example, a computer having an arithmetic circuit such as a CPU (Central Processing Unit), a memory, and the like. The control contents of the control device 100 will be described later.

[0014] (Liquefaction line) The raw material pipe 10, the raw material supply unit 12, the liquid storage unit 14, the raw material cooling unit 40, the raw material expansion unit 48, and the magnetic refrigeration unit 50 constitute a liquefaction line that liquefies the raw material gas HG. The raw material pipe 10 is a pipe through which the raw material gas HG and the liquid HL pass. The raw material supply unit 12 is a mechanism that is connected to the raw material pipe 10 and supplies the raw material gas HG to the raw material pipe 10. The raw material supply unit 12 may be, for example, a container in which the raw material gas HG is stored. The liquid storage unit 14 is a mechanism that is connected to the raw material pipe 10 and supplies the liquid HL liquefied in the raw material pipe 10. The liquid storage unit 14 may be, for example, a container in which the liquid HL is stored. In the example of this embodiment, one end of the raw material pipe 10 is connected to the raw material supply unit 12, and the other end of the raw material pipe 10 is connected to the liquid storage unit 14. Hereinafter, the direction from the raw material supply unit 12 toward the liquid reservoir 14 in the raw material piping 10, that is, the direction in which the raw material gas HG and the liquid HL flow in the raw material piping 10, is referred to as the raw material flow direction DH.

[0015] The raw material cooling section 40, the raw material expansion section 48, and the magnetic refrigeration section 50 will be described later.

[0016] (Nitrogen line) The nitrogen pipes 20, 22 and the nitrogen supply unit 24 constitute a nitrogen line that conducts nitrogen for cooling the raw material gas HG. The nitrogen pipe 20 is a pipe through which liquid nitrogen NL passes. The nitrogen supply unit 24 is a mechanism that is connected to the nitrogen pipe 20 and supplies liquid nitrogen NL to the nitrogen pipe 20. The nitrogen supply unit 24 may be, for example, a container in which liquid nitrogen NL is stored. In this embodiment, one end of the nitrogen pipe 20 is connected to the nitrogen supply unit 24, and the other end of the nitrogen pipe 20 is connected to a third raw material cooling unit 44 described later. The third raw material cooling unit 44 is supplied with liquid nitrogen NL from the nitrogen pipe 20.

[0017] The nitrogen pipe 22 is a pipe through which nitrogen gas NG, which is vaporized liquid nitrogen NL, passes. The nitrogen pipe 22 is connected to the third raw material cooling section 44. That is, at least a part of the liquid nitrogen NL is vaporized in the third raw material cooling section 44 to become nitrogen gas NG, and the nitrogen gas NG is introduced into the nitrogen pipe 22.

[0018] In this embodiment, the raw material gas HG is cooled by the liquid nitrogen NL and nitrogen gas NG flowing through the nitrogen line, but the nitrogen line is not an essential component. That is, cooling of the raw material gas HG by the liquid nitrogen NL and nitrogen gas NG is not essential. The raw material gas HG may be cooled by at least the refrigerant C described below.

[0019] (Refrigerant line) The refrigerant pipe 30, the refrigerant compression section 32, the refrigerant cooling section 34, and the refrigerant expansion sections 36 and 38 constitute a refrigerant line that conducts a refrigerant C for cooling the raw material gas HG. The refrigerant C may be any substance capable of cooling the raw material gas HG, but is hydrogen in this embodiment.

[0020] The refrigerant piping 30 is a pipe through which the refrigerant C passes. The refrigerant compression section 32 is connected to the refrigerant piping 30. The refrigerant compression section 32 increases the temperature of the refrigerant C by compressing the refrigerant C. More specifically, the refrigerant compression section 32 compresses the refrigerant C after cooling the raw material gas HG (the refrigerant C after heat exchange in the raw material cooling section 40 described below). The refrigerant compression section 32 may be any mechanism capable of compressing the refrigerant C, but in this embodiment, a compression turbine that compresses the refrigerant C is used.

[0021] The refrigerant pipe 30 is a loop-shaped pipe in which the refrigerant C circulates inside the refrigerant pipe 30. That is, one end of the refrigerant pipe 30 is connected to the outlet 32A of the refrigerant compression section 32, and the other end is connected to the inlet 32B of the refrigerant compression section 32. The outlet 32A is the outlet from which the refrigerant C compressed in the refrigerant compression section 32 is discharged, and the inlet 32B is the inlet through which the refrigerant C is introduced into the refrigerant compression section 32. Hereinafter, the direction from the outlet 32A to the inlet 32B inside the refrigerant pipe 30, that is, the direction in which the refrigerant C flows inside the refrigerant pipe 30, is referred to as the refrigerant flow direction DC. That is, it can be said that the start point of the refrigerant flow direction DC is the outlet 32A, and the end point of the refrigerant flow direction DC is the inlet 32B.

[0022] The refrigerant cooling unit 34 is a heat exchanger that cools the refrigerant C flowing through the refrigerant pipe 30. The refrigerant cooling unit 34 is provided at a position on the refrigerant flow direction DC side (downstream side of the flow of the refrigerant C) of the refrigerant compression unit 32 and in contact with the refrigerant pipe 30. Thus, the refrigerant cooling unit 34 cools the refrigerant C flowing through the refrigerant pipe 30 after being compressed by the refrigerant compression unit 32. Note that the contact here is not limited to direct contact, but also includes contact via other members (solid, liquid, or gas), and the same applies hereinafter. That is, for example, the refrigerant cooling unit 34 may be in direct contact with the refrigerant pipe 30 at a position on the refrigerant flow direction DC side of the refrigerant compression unit 32, or may be in contact via other members (solid, liquid, or gas).

[0023] The refrigerant cooling unit 34 may use any method for cooling the refrigerant C. For example, the refrigerant cooling unit 34 may have a cooling liquid piping through which a cooling liquid (e.g., water) flows and a member in contact with the cooling liquid piping and the refrigerant piping 30, and may cool the refrigerant C by exchanging heat between the cooling liquid flowing through the cooling liquid piping and the refrigerant C flowing through the refrigerant piping 30.

[0024] The refrigerant expansion section 36 is connected to the refrigerant pipe 30 on the side in the refrigerant flow direction DC of the refrigerant compression section 32, and in this embodiment, on the side in the refrigerant flow direction DC of the refrigerant cooling section 34. The refrigerant expansion section 36 expands the refrigerant C flowing through the refrigerant pipe 30 to cool the refrigerant C. The refrigerant compression section 32 may be any mechanism capable of expanding the refrigerant C, and may use, for example, a two-phase expansion turbine or a Joule-Thomson valve, but in this embodiment, a Joule-Thomson valve is used.

[0025] The refrigerant expansion section 36 is connected in series to the refrigerant pipe 30. That is, an inlet (an inlet into which the refrigerant C is introduced) of the refrigerant expansion section 36 is connected to the refrigerant flow direction DC side of the position where the refrigerant compression section 32 (refrigerant cooling section 34) of the refrigerant pipe 30 is provided. And, an outlet (an outlet from which the refrigerant C is discharged) of the refrigerant expansion section 36 is connected to the opposite side in the refrigerant flow direction DC (upstream side) of the position where the refrigerant compression section 32 of the refrigerant pipe 30 is provided.

[0026] The refrigerant expansion section 38 is connected to the refrigerant pipe 30 on the side in the refrigerant flow direction DC of the refrigerant compression section 32, and in this embodiment, on the side in the refrigerant flow direction DC of the refrigerant cooling section 34. The refrigerant expansion section 38 cools the refrigerant C by expanding the refrigerant C flowing through the refrigerant pipe 30. The refrigerant expansion section 38 may be any mechanism capable of expanding the refrigerant C, and may use, for example, a two-phase expansion turbine or a Joule-Thomson valve, but in this embodiment, a two-phase expansion turbine is used.

[0027] The refrigerant expansion section 38 is connected in parallel (branched) to the refrigerant piping 30. The inlet of the refrigerant expansion section 38 (the inlet into which the refrigerant C is introduced) is connected to a location between the position where the refrigerant cooling section 34 of the refrigerant piping 30 is provided and the position where the refrigerant expansion section 36 is provided in the refrigerant flow direction DC (more specifically, a location between the second feedstock cooling section 42 and the fourth feedstock cooling section 46 described later). The outlet of the refrigerant expansion section 38 (the outlet from which the refrigerant C is discharged) is connected to a location between the position where the refrigerant expansion section 36 of the refrigerant piping 30 is provided and the position where the refrigerant compression section 32 is provided in the refrigerant flow direction DC (more specifically, a location between the fourth feedstock cooling section 46 and the second feedstock cooling section 42 described later).

[0028] (raw material cooling section) The raw material cooling section 40 is a mechanism for cooling the raw material gas HG flowing through the raw material piping 10 by the refrigerant C. Any method for cooling the raw material gas HG by the raw material cooling section 40 may be used, but in this embodiment, the raw material gas HG is cooled by exchanging heat between the refrigerant C flowing through the refrigerant piping 30 and the raw material gas HG flowing through the raw material piping 10. That is, the raw material cooling section 40 in this embodiment is a heat exchanger.

[0029] The number of raw material cooling sections (heat exchangers) included in raw material cooling section 40 may be arbitrary, but in this embodiment, raw material cooling section 40 is provided with a first raw material cooling section 41, a second raw material cooling section 42, a third raw material cooling section 44, and a fourth raw material cooling section 46. Each raw material cooling section will be described below.

[0030] (1st raw material cooling section) First raw material cooling section 41 is provided at a position closer to the raw material flow direction DH (downstream of the flow of raw material gas HG) than raw material supply section 12 and in contact with raw material piping 10. First raw material cooling section 41 is also provided at a position in contact with nitrogen piping 22. First raw material cooling section 41 cools the raw material gas HG by exchanging heat between the raw material gas HG flowing through raw material piping 10 and the nitrogen gas NG flowing through nitrogen piping 22.

[0031] The first raw material cooling section 41 preferably cools the raw material gas HG to a temperature of, for example, −50° C. to −100° C. or lower.

[0032] (Second raw material cooling section) The second raw material cooling section 42 is provided at a position closer to the raw material flow direction DH than the raw material supply section 12 and in contact with the raw material piping 10. The second raw material cooling section 42 is also provided at a position in contact with the refrigerant piping 30. The second raw material cooling section 42 cools the raw material gas HG by exchanging heat between the raw material gas HG flowing through the raw material piping 10 and the refrigerant C flowing through the refrigerant piping 30.

[0033] More specifically, in this embodiment, second feedstock cooling section 42 is provided on the side of first feedstock cooling section 41 in the feedstock flow direction DH. Moreover, second feedstock cooling section 42 is provided at a location on refrigerant piping 30, in terms of refrigerant flow direction DC, between the position where fourth feedstock cooling section 46 is provided and the position where refrigerant compression section 32 is provided. Therefore, second feedstock cooling section 42 further cools the feedstock gas HG, which has been cooled in first feedstock cooling section 41, by refrigerant C flowing through refrigerant piping 30 from fourth feedstock cooling section 46 in the refrigerant flow direction DC.

[0034] In this embodiment, second raw material cooling section 42 is provided in refrigerant flow direction DC, at a location on refrigerant piping 30 between the position where refrigerant cooling section 34 is provided and the position where fourth raw material cooling section 46 is provided. Therefore, second raw material cooling section 42 also cools refrigerant C that has been cooled in refrigerant cooling section 34, by refrigerant C flowing through refrigerant piping 30 from fourth raw material cooling section 46 in refrigerant flow direction DC.

[0035] The second raw material cooling section 42 preferably cools the raw material gas HG to a temperature of, for example, −100° C. to −150° C. or lower.

[0036] (3rd raw material cooling section) Third raw material cooling section 44 is connected to nitrogen piping 20 and stores liquid nitrogen NL supplied from nitrogen piping 20. A portion of raw material piping 10 on the raw material flow direction DH side of second raw material cooling section 42 passes through third raw material cooling section 44. Third raw material cooling section 44 exchanges heat between the stored liquid nitrogen NL and raw material gas HG passing through raw material piping 10 in third raw material cooling section 44, thereby further cooling the raw material gas HG after being cooled in second raw material cooling section 42 with liquid nitrogen NL. The liquid nitrogen NL, whose temperature has been increased by the heat exchange, is vaporized and discharged to nitrogen piping 22 as nitrogen gas NG.

[0037] In this embodiment, in the third feedstock cooling section 44, the feedstock pipe 10 is connected to an ortho-para conversion catalyst 44A. The ortho-para conversion catalyst 44A is a catalyst that promotes the conversion of ortho-hydrogen to para-hydrogen (ortho-para conversion). The ortho-hydrogen contained in the feedstock gas HG passing through the feedstock pipe 10 in the third feedstock cooling section 44 is converted to para-hydrogen by contacting with the ortho-para conversion catalyst 44A. In addition, the feedstock gas HG generates heat during ortho-para conversion, but the temperature rise can be suppressed by cooling it with liquid nitrogen NL.

[0038] The third raw material cooling section 44 preferably cools the raw material gas HG to a temperature of, for example, −180° C. or lower.

[0039] (4th raw material cooling section) Fourth raw material cooling section 46 is provided at a position closer to raw material flow direction DH than raw material supply section 12 and in contact with raw material piping 10. Fourth raw material cooling section 46 is also provided at a position in contact with refrigerant piping 30. Fourth raw material cooling section 46 cools raw material gas HG by exchanging heat between raw material gas HG flowing through raw material piping 10 and refrigerant C flowing through refrigerant piping 30.

[0040] More specifically, in this embodiment, fourth feedstock cooling section 46 is provided on the feedstock flow direction DH side of third feedstock cooling section 44. Moreover, fourth feedstock cooling section 46 is provided at a location in refrigerant flow direction DC, between the position of refrigerant expansion section 36 and the position of second feedstock cooling section 42, of refrigerant pipe 30. Therefore, fourth feedstock cooling section 46 further cools the feedstock gas HG after being cooled in third feedstock cooling section 44, by refrigerant C flowing through refrigerant pipe 30 from refrigerant expansion section 36 in refrigerant flow direction DC.

[0041] In this embodiment, fourth raw material cooling section 46 is provided in a location on refrigerant pipe 30 in refrigerant flow direction DC between the position where second raw material cooling section 42 is provided and the position where refrigerant expansion section 36 is provided. Therefore, fourth raw material cooling section 46 also cools refrigerant C after heat exchange in second raw material cooling section 42 by refrigerant C flowing through refrigerant pipe 30 from refrigerant expansion section 36 in refrigerant flow direction DC.

[0042] In this embodiment, the raw material piping 10 is connected to the ortho-para conversion catalyst 46A even at the position where it contacts the fourth raw material cooling section 46. The ortho-para conversion catalyst 46A is a catalyst that promotes the conversion of ortho-hydrogen to para-hydrogen (ortho-para conversion). The ortho-hydrogen contained in the raw material gas HG passing through the raw material piping 10 is converted to para-hydrogen by contacting the ortho-para conversion catalyst 46A. In addition, the raw material gas HG generates heat during ortho-para conversion, but by being cooled by the fourth raw material cooling section 46, the temperature rise can be suppressed.

[0043] The fourth raw material cooling section 46 preferably cools the raw material gas HG to a temperature of, for example, −240° C. or higher and −220° C. or lower.

[0044] (Raw material expansion part) The feedstock expansion section 48 is connected to the feedstock piping 10 on the side of the feedstock flow direction DH of the feedstock cooling section 40, and in this embodiment on the side of the fourth feedstock cooling section 46 in the feedstock flow direction DH. The feedstock expansion section 48 expands the feedstock gas HG flowing through the feedstock piping 10 cooled in the feedstock cooling section 40, thereby vaporizing at least a portion of the feedstock gas HG to produce liquid HL. The feedstock expansion section 48 may be any mechanism capable of expanding the feedstock gas HG, such as a two-phase expansion turbine or a Joule-Thomson valve, but in this embodiment, a two-phase expansion turbine is used.

[0045] The raw material expansion section 48 is connected in series to the raw material piping 10. That is, the inlet of the raw material expansion section 48 (the inlet through which the raw material gas HG is introduced) is connected on the side of the raw material flow direction DH from the position where the raw material cooling section 40 (the fourth raw material cooling section 46 in this embodiment) is provided. And the outlet of the raw material expansion section 48 (the outlet from which the raw material gas HG and liquid HL are discharged) is connected on the opposite side in the raw material flow direction DH (upstream side) from the position where the magnetic refrigeration section 50 described later is provided.

[0046] However, the raw material expansion section 48 is not an essential component. For example, the liquefaction apparatus 1 may not have the raw material expansion section 48, and the raw material gas HG cooled in the raw material cooling section 40 may be liquefied only by the magnetic refrigeration section 50 described later.

[0047] (Magnetic Refrigeration Unit) The magnetic refrigeration unit 50 is provided at a position closer to the raw material flow direction DH than the raw material cooling unit 40 and in contact with the raw material piping 10. The magnetic refrigeration unit 50 cools the raw material gas HG flowing through the raw material piping 10 after being cooled by the raw material cooling unit 40 using a magnetic body 54 (see FIG. 2 described later), and liquefies the raw material gas HG to generate liquid HL. That is, the magnetic refrigeration unit 50 liquefies the raw material gas HG by a magnetic refrigeration method.

[0048] More specifically, in this embodiment, the magnetic refrigeration unit 50 is provided at a position closer to the raw material flow direction DH than the raw material expansion unit 48 and in contact with the raw material piping 10. The magnetic refrigeration unit 50 uses a magnetic body 54 to cool the raw material gas HG that remains vaporized and not liquefied after being expanded in the raw material expansion unit 48, and liquefies the raw material gas HG to generate a liquid HL.

[0049] The magnetic refrigeration unit 50 preferably cools the liquid HL (raw material gas HG) to a temperature of, for example, −250° C. or lower.

[0050] The liquid HL generated by the magnetic refrigeration unit 50 is introduced from inside the raw material pipe 10 into the liquid storage unit 14 and stored in the liquid storage unit 14.

[0051] (Magnetic material cooling section) The magnetic body cooling unit 60 is a mechanism that cools the magnetic body 54 of the magnetic refrigeration unit 50 by the refrigerant C. The magnetic body cooling unit 60 cools the magnetic body 54 by exchanging heat between the refrigerant C flowing through the refrigerant pipe 30 and the magnetic body 54.

[0052] The magnetic material cooling section 60 is provided at a position in contact with the magnetic material 54. The magnetic material cooling section 60 is also provided at a location in the refrigerant flow direction DC, between the position where the refrigerant expansion section 36 is provided and the position where the fourth raw material cooling section 46 is provided, of the refrigerant pipe 30. Therefore, the magnetic material cooling section 60 cools the magnetic material 54 by the refrigerant C flowing through the refrigerant pipe 30 from the refrigerant expansion section 36 in the refrigerant flow direction DC.

[0053] In this way, the magnetic material cooling section 60 cools the magnetic material 54 by the refrigerant C cooled in the refrigerant expansion section 36. Therefore, the magnetic material 54 can be cooled by the refrigerant C that is at the lowest temperature in the refrigerant line. In this embodiment, the raw material gas HG is pre-cooled in the raw material cooling section 40 by the refrigerant C after cooling the magnetic material 54. More specifically, the refrigerant C after cooling the magnetic material 54 flows in the refrigerant line in the order of the fourth raw material cooling section 46 and the second raw material cooling section 42. Therefore, the temperature of the refrigerant C decreases in the order of the second raw material cooling section 42, the fourth raw material cooling section 46, and the magnetic material cooling section 60. Therefore, the raw material gas HG and the magnetic material 54 can be efficiently cooled by the refrigerant C.

[0054] (Refrigeration cycle of magnetic refrigeration unit) A specific example of the refrigeration cycle of the magnetic refrigeration unit 50 will be described. FIG. 2 is a schematic diagram for explaining an example of the refrigeration cycle of the magnetic refrigeration unit. In the example of FIG. 2, the magnetic refrigeration unit 50 has a shaft portion 52, a magnetic body 54, and a magnet 56. The shaft portion 52 is a shaft-shaped member. The magnetic body 54 is a member whose temperature changes with a change in magnetic flux density. The material of the magnetic body 54 may be any material whose temperature changes with a change in magnetic flux density, and examples of the material include gadolinium compounds. The magnetic body 54 is attached to the shaft portion 52 so as to be movable in the axial direction. For example, the control device 100 may control a drive mechanism that moves the magnetic body 54 in the axial direction to move the magnetic body 54.

[0055] The magnet 56 is a magnet that generates a magnetic field. The magnet 56 may be an electromagnet or a permanent magnet. In the example of FIG. 2, the magnet 56 is annular and is disposed so as to surround the shaft portion 52.

[0056] As shown in step S1 of FIG. 2, when cooling the magnetic body 54, a magnetic field is applied to the magnetic body 54 by the magnet 56. The temperature of the magnetic body 54 increases when the magnetic field is applied to it. Any method may be used for applying a magnetic field from the magnet 56 to the magnetic body 54. For example, when the magnet 56 is an electromagnet, the control device 100 may apply a current to the magnet 56 to generate a magnetic field from the magnet 56 and apply the magnetic field to the magnetic body 54. Furthermore, when the magnet 56 is a permanent magnet, the magnetic body 54 may be positioned inside the inner circumferential surface of the magnet 56 and a magnetic field may be applied to the magnetic body 54.

[0057] Then, as shown in step S2, the magnetic body 54, whose temperature has increased due to the application of the magnetic field, is brought into contact with the magnetic body cooling unit 60 (refrigerant piping 30). As a result, in the magnetic body cooling unit 60, heat exchange occurs between the magnetic body 54 and the refrigerant C, and the magnetic body 54 is cooled (heat is discharged).

[0058] Thereafter, as shown in step S3, the application of the magnetic field from the magnet 56 to the magnetic body 54 is stopped. This causes the magnetic body 54 to further cool. The method of stopping the application of the magnetic field to the magnetic body 54 may be arbitrary. For example, when the magnet 56 is an electromagnet, the control device 100 may stop the application of the magnetic field to the magnetic body 54 by stopping the application of the current to the magnet 56. Also, for example, when the magnet 56 is a permanent magnet, the application of the magnetic field to the magnetic body 54 may be stopped by moving the magnetic body 54 away from the magnet 56. The magnetic body 54, which has been cooled by stopping the application of the magnetic field, comes into contact with the raw material pipe 10 and cools the raw material gas HG in the raw material pipe 10, thereby liquefying the raw material gas HG. When the temperature of the magnetic body 54 rises due to the liquefaction of the raw material gas HG, the process returns to step S1, and the same refrigeration cycle is repeated.

[0059] However, the refrigeration cycle of the magnetic refrigeration unit 50 is not limited to the one shown in the example of Fig. 2. For example, in the example of Fig. 2, the magnetic body 54 is configured to be movable along the shaft portion 52, but this is not limited thereto, and the position of the magnetic body 54 may be fixed. Also, for example, the magnetic body 54 cools the raw material gas HG by contacting the outer circumferential surface of the raw material pipe 10, but this is not limited thereto, and the magnetic body 54 may be inserted into the raw material pipe 10 and directly contact the raw material gas HG in the raw material pipe 10 to cool the raw material gas HG.

[0060] (Liquefaction method) The flow of the method for liquefying the raw material gas HG using the above-described liquefaction apparatus 1 will be described with reference to a flowchart. Fig. 3 is a flowchart for explaining the method for liquefying the raw material gas.

[0061] As shown in FIG. 3, in this method, the raw material cooling section 40 cools the raw material gas HG with the refrigerant C (step S10). In this step, the controller 100 causes the raw material supply section 12 to supply the raw material gas HG into the raw material piping 10. In this case, for example, the controller 100 may control the valve of the raw material supply section 12 to supply the raw material gas HG from the raw material supply section 12. In addition, the controller 100 causes the nitrogen supply section 24 to supply liquid nitrogen NL into the nitrogen piping 20. In this case, for example, the controller 100 may control the valve of the nitrogen supply section 24 to supply the liquid nitrogen NL from the nitrogen supply section 24. In addition, the controller 100 operates the refrigerant compression section 32, the refrigerant cooling section 34, and the refrigerant expansion sections 36 and 38 to circulate the refrigerant C in the refrigerant piping 30. As a result, the raw material gas HG flows in the raw material piping 10 along the raw material flow direction DH while being cooled by the raw material cooling section 40. Specifically, the raw material gas HG is cooled in first raw material cooling section 41 by nitrogen gas NG flowing through nitrogen piping 22. Then, the raw material gas HG cooled in first raw material cooling section 41 is further cooled in second raw material cooling section 42 by refrigerant C flowing through refrigerant piping 30. Then, the raw material gas HG cooled in second raw material cooling section 42 is cooled by liquid nitrogen NL while undergoing ortho-para conversion in third raw material cooling section 44. Then, the raw material gas HG cooled in third raw material cooling section 44 is cooled in fourth raw material cooling section 46 by refrigerant C flowing through refrigerant piping 30 while undergoing ortho-para conversion.

[0062] Next, in this method, the raw material gas HG after being cooled in the raw material cooling section 40 is expanded in the raw material expansion section 48 to further cool the raw material gas HG (step S12). When the raw material expansion section 48 is a two-phase turbine, the control device 100 operates the raw material expansion section 48 to expand the raw material gas HG by the raw material expansion section 48. Also, for example, when the raw material expansion section 48 is a Joule-Thomson valve, the raw material gas HG expands by passing through the raw material expansion section 48 which is a Joule-Thomson valve. At least a portion of the raw material gas HG expanded in the raw material expansion section 48 is liquefied to become the raw material liquid HL.

[0063] Next, in this method, the raw material gas HG after being expanded in the raw material expansion section 48 is further cooled by the magnetic refrigeration section 50 (step S14). The control device 100 brings the magnetic body 54 of the magnetic refrigeration section 50 into contact with the raw material piping 10, thereby exchanging heat between the magnetic body 54 and the raw material gas HG, thereby cooling the raw material gas HG. At least a portion of the raw material gas HG cooled in the magnetic refrigeration section 50 is liquefied to become the liquid HL. In this embodiment, it is preferable to liquefy all of the raw material gas HG that remains vaporized even after being expanded in the raw material expansion section 48.

[0064] Through the above steps, the source gas HG is liquefied to produce the liquid HL. The liquefaction apparatus 1 cools the magnetic body 54 after cooling the source gas HG in a cycle as described in steps S1, S2, and S3 of FIG. 2. That is, the magnetic body 54 after cooling the source gas HG is heated by applying a magnetic field by the magnet 56, and then is cooled further by discharging heat (cooling) with the refrigerant C and stopping the application of the magnetic field. The magnetic body 54 cooled in such a cycle is reused to cool the source gas HG.

[0065] In this manner, in the present embodiment, the raw gas HG pre-cooled with the refrigerant C is magnetically refrigerated by the magnetic refrigeration unit 50 and liquefied. According to the present embodiment, the liquefaction efficiency of the raw gas HG can be improved by using magnetic refrigeration. Furthermore, in the present embodiment, the magnetic body 54 of the magnetic refrigeration unit 50 is cooled by the refrigerant C used for pre-cooling the raw gas HG. Therefore, it is possible to efficiently perform the refrigeration cycle of the magnetic body 54 and the pre-cooling of the raw gas HG. Furthermore, in the present embodiment, the raw gas HG pre-cooled with the refrigerant C is expanded in the raw expansion unit 48 and then cooled in the magnetic refrigeration unit 50. In this manner, the raw gas HG is liquefied in a two-stage process of expansion and magnetic refrigeration, thereby more suitably improving the liquefaction efficiency.

[0066] (effect) As described above, the liquefaction apparatus 1 according to the first embodiment of the present disclosure includes the raw material pipe 10 through which the raw material gas HG flows, the raw material cooling unit 40 that cools the raw material gas HG flowing through the raw material pipe 10 with the refrigerant C, the magnetic refrigeration unit 50 that is provided downstream of the flow of the raw material gas HG in the raw material pipe 10 (on the raw material flow direction DH side) of the raw material cooling unit 40 and liquefies the raw material gas HG by cooling the cooled raw material gas HG with the magnetic body 54, and the magnetic body cooling unit 60 that cools the magnetic body 54 that has cooled the raw material gas HG with the refrigerant C. According to the present disclosure, the liquefaction efficiency of the raw material gas HG is improved by using magnetic refrigeration, while the refrigeration cycle of the magnetic body 54 and the pre-cooling of the raw material gas HG can be efficiently performed by cooling the magnetic body 54 of the magnetic refrigeration unit 50 with the refrigerant C used for pre-cooling the raw material gas HG.

[0067] The liquefaction apparatus 1 according to a second embodiment of the present disclosure is the liquefaction apparatus according to the first embodiment, and further includes a raw material expansion section 48 that is provided between the raw material cooling section 40 and the magnetic refrigeration section 50 in the flow of the raw material gas HG in the raw material piping 10, and expands the raw material gas HG cooled by the refrigerant C to liquefy a part of the raw material gas HG. According to the present disclosure, the liquefaction efficiency can be more suitably improved by liquefying the raw material gas HG in a two-stage process of expansion and magnetic refrigeration.

[0068] The liquefaction apparatus 1 according to a third aspect of the present disclosure is the liquefaction apparatus according to the second aspect, and uses a two-phase expansion turbine or a Joule-Thomson valve as the feed expansion section 48. According to the present disclosure, the feed gas HG cooled by the refrigerant C can be appropriately expanded, and the liquefaction efficiency can be more suitably improved.

[0069] The liquefaction apparatus 1 according to a fourth aspect of the present disclosure is the liquefaction apparatus according to any one of the first to third aspects, and further includes a refrigerant expansion section 36 that cools the refrigerant C by expanding it. The magnetic material cooling section 60 cools the magnetic material 54 with the refrigerant C cooled by the refrigerant expansion section 36, and the raw material cooling section 40 cools the raw material gas HG with the refrigerant C after cooling the magnetic material 54. According to the present disclosure, the refrigeration cycle of the magnetic material 54 and the pre-cooling of the raw material gas HG can be efficiently performed.

[0070] The liquefaction apparatus 1 according to a fifth aspect of the present disclosure is the liquefaction apparatus according to the fourth aspect, further including a refrigerant compression unit 32 that compresses the refrigerant C obtained by cooling the raw material gas HG, and a refrigerant cooling unit 34 that cools the compressed refrigerant C. According to the present disclosure, the magnetic body 54 is cooled, the raw material gas HG is pre-cooled, and then the refrigerant C is compressed to discharge heat, thereby enabling efficient cooling by the refrigerant C.

[0071] A liquefaction apparatus 1 according to a sixth aspect of the present disclosure is the liquefaction apparatus according to any one of the first to fifth aspects, in which the raw material gas HG is hydrogen gas. According to the present disclosure, hydrogen can be appropriately liquefied.

[0072] A liquefaction method according to a seventh aspect of the present disclosure includes the steps of cooling a source gas HG with a refrigerant C, cooling the source gas HG cooled by the refrigerant C with a magnetic body 54 to liquefy the source gas HG, and cooling the magnetic body 54 that has cooled the source gas HG with the refrigerant C. According to the present disclosure, the refrigeration cycle of the magnetic body 54 and the pre-cooling of the source gas HG can be efficiently performed while improving the liquefaction efficiency of the source gas HG.

[0073] A liquefaction method according to an eighth aspect of the present disclosure is the liquefaction method according to the seventh aspect, further including a step of expanding the raw gas HG cooled by the refrigerant C to liquefy a part of the raw gas HG, and in the step of liquefying the raw gas HG by the magnetic body 54, the raw gas HG that has not been liquefied by the expansion is liquefied. According to the present disclosure, the liquefaction efficiency can be more suitably improved by liquefying the raw gas HG in a two-stage process of expansion and magnetic refrigeration.

[0074] Although the embodiment of the present disclosure has been described above, the embodiment is not limited by the contents of this embodiment. In addition, the above-mentioned components include those that a person skilled in the art can easily imagine, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the above-mentioned components can be appropriately combined. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the gist of the above-mentioned embodiment. [Explanation of symbols]

[0075] 1 Liquefier 10 Raw material piping 12 Raw material supply department 14 Liquid storage section 20, 22 Nitrogen piping 24 Nitrogen supply unit 30 Refrigerant piping 32 Refrigerant compression section 34 Refrigerant cooling section 36, 38 Refrigerant expansion section 40 Raw material cooling section 48 Raw material expansion section 50 Magnetic Refrigeration Unit 54 Magnetic material 60 Magnetic cooling section C Refrigerant HG raw gas HL liquid

Claims

1. A raw material pipe through which a raw material gas flows; a raw material cooling section that cools the raw material gas flowing through the raw material pipe by a refrigerant; a magnetic refrigeration unit that is provided downstream of the raw material cooling unit in a flow direction of the raw material gas in the raw material pipe and that cools the cooled raw material gas by a magnetic body to liquefy the raw material gas; a magnetic material cooling unit that cools the magnetic material obtained by cooling the raw material gas by the refrigerant; having Liquefaction equipment.

2. The liquefaction apparatus according to claim 1, further comprising a raw material expansion section provided between the raw material cooling section and the magnetic refrigeration section in the flow of the raw material gas in the raw material piping, and configured to expand the raw material gas cooled by the refrigerant to liquefy a portion of the raw material gas.

3. 3. The liquefaction apparatus according to claim 2, wherein the feed expansion section is a two-phase expansion turbine or a Joule-Thomson valve.

4. The cooling device further includes a refrigerant expansion section that expands and cools the refrigerant, the magnetic body cooling unit cools the magnetic body by the refrigerant cooled by the refrigerant expansion unit, The liquefaction apparatus according to claim 1 , wherein the raw material cooling section cools the raw material gas with the refrigerant after cooling the magnetic body.

5. 5. The liquefaction apparatus according to claim 4, further comprising: a refrigerant compression section that compresses the refrigerant that has cooled the raw material gas; and a refrigerant cooling section that cools the compressed refrigerant.

6. The liquefaction apparatus according to any one of claims 1 to 3, wherein the raw material gas is hydrogen gas.

7. cooling the raw material gas with a refrigerant; a step of cooling the raw material gas cooled by the refrigerant with a magnetic material to liquefy the raw material gas; cooling the magnetic body obtained by cooling the raw material gas by the refrigerant; A liquefaction method comprising:

8. The method further includes a step of expanding the raw material gas cooled by the refrigerant to liquefy a portion of the raw material gas, The liquefaction method according to claim 7 , wherein in the step of liquefying the source gas by the magnetic body, the source gas that has not been liquefied due to expansion is liquefied.

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