Liquefaction device and liquefaction method

Abstract

The present invention improves the efficiency of liquefying a material gas. This liquefaction device comprises: a material pipe through which a material gas flows; a magnetic body which is connected to the material pipe and is capable of adsorbing the material gas supplied from the material pipe, the temperature of the magnetic body decreasing when application of a magnetic field is stopped; and a magnet which applies the magnetic field to the magnetic body. The magnet stops applying the magnetic field to the magnetic body in a state in which the magnetic body has adsorbed the material gas, whereby the magnetic body cools the adsorbed material gas.

Description

Liquefaction device and liquefaction method

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

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

[0003] Seiji Yamashita et al., "Development of Hydrogen Liquefaction Storage System," Journal of Japan Society of Energy and Resources, Vol. 37, No. 4

[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 that can improve the efficiency of liquefying a raw material gas.

[0006] The liquefaction apparatus according to the present disclosure comprises a raw material pipe through which a raw material gas flows, a magnetic body connected to the raw material pipe and capable of adsorbing the raw material gas supplied from the raw material pipe, the temperature of which decreases when the application of a magnetic field is stopped, and a magnet that applies a magnetic field to the magnetic body, wherein the magnet stops applying the magnetic field to the magnetic body while the magnetic body has adsorbed the raw material gas, thereby causing the magnetic body to cool the adsorbed raw material gas.

[0007] The liquefaction method according to the present disclosure includes the steps of: adsorbing a raw material gas onto a magnetic material that is capable of adsorbing the raw material gas and whose temperature decreases when the application of a magnetic field is stopped; and cooling the adsorbed raw material gas by the magnetic material by stopping the application of a magnetic field to the magnetic material while the magnetic material has adsorbed the raw material gas.

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

[0009] Fig. 1 is a schematic diagram of a liquefaction apparatus according to this embodiment. Fig. 2 is a flowchart illustrating a method for liquefying a raw material gas. Fig. 3 is a schematic diagram illustrating adsorption of the raw material gas. Fig. 4 is a schematic diagram illustrating cooling of the adsorbed raw material gas.

[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 configurations in which the respective embodiments are combined.

[0011] (Liquefaction Apparatus) 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. Furthermore, 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 includes a raw material piping 10, a raw material supply unit 12, a liquid storage unit 14, nitrogen piping 20, 22, a nitrogen supply unit 24, a refrigerant piping 30, a refrigerant compression unit 32, a refrigerant cooling unit 34, refrigerant expansion units 36, 38, a raw material cooling unit 40, a raw material storage unit 50, a magnetic refrigeration unit 60, a magnetic material cooling unit 70, a raw material expansion unit 80, and a control device 100.

[0013] The control device 100 is a controller that controls each mechanism of the liquefaction device 1. The control device 100 controls each mechanism of the liquefaction device 1, causing the liquefaction device 1 to liquefy the raw material gas HG and produce the 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, etc. The control content 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 storage unit 50, the magnetic refrigeration unit 60, and the raw material expansion unit 80 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 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 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 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 to the liquid reservoir 14 in the raw material pipe 10, that is, the direction in which the raw material gas HG and the liquid HL flow in the raw material pipe 10, will be referred to as the raw material flow direction DH.

[0015] The raw material cooling section 40, raw material storage section 50, magnetic refrigeration section 60, and raw material expansion section 80 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 that stores liquid nitrogen NL. 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, which will be described later. Liquid nitrogen NL is supplied to the third raw material cooling unit 44 from the nitrogen pipe 20.

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

[0018] In this embodiment, the source 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 source gas HG by the liquid nitrogen NL and nitrogen gas NG is not essential. The source 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 that can cool the raw material gas HG, but in this embodiment, it is hydrogen.

[0020] The refrigerant piping 30 is a piping through which the refrigerant C passes. The refrigerant compression unit 32 is connected to the refrigerant piping 30. The refrigerant compression unit 32 increases the temperature of the refrigerant C by compressing the refrigerant C. More specifically, the refrigerant compression unit 32 compresses the refrigerant C after cooling the raw material gas HG (the refrigerant C after heat exchange in the raw material cooling unit 40 described below). The refrigerant compression unit 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 piping 30 is a loop-shaped pipe through which the refrigerant C circulates. That is, one end of the refrigerant piping 30 is connected to an outlet 32A of the refrigerant compression section 32, and the other end is connected to an 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 in the refrigerant piping 30, i.e., the direction in which the refrigerant C flows within the refrigerant piping 30, is referred to as the refrigerant flow direction DC. That is, 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 located closer to the refrigerant flow direction DC than the refrigerant compression unit 32 (downstream of the flow of the refrigerant C) and in contact with the refrigerant pipe 30. Therefore, 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 term "contact" here does not necessarily mean direct contact, but also includes contact via another member (solid, liquid, or gas), and this also applies hereinafter. That is, for example, the refrigerant cooling unit 34 may be in direct contact with the refrigerant pipe 30 at a position closer to the refrigerant flow direction DC than the refrigerant compression unit 32, or may be in contact via another member (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 coolant pipe through which a coolant (e.g., water) flows and a member that contacts the coolant pipe and the refrigerant pipe 30, and may cool the refrigerant C by exchanging heat between the coolant flowing through the coolant pipe and the refrigerant C flowing through the refrigerant pipe 30.

[0024] The refrigerant expansion section 36 is connected to the refrigerant pipe 30 on the refrigerant flow direction DC side of the refrigerant compression section 32, and in this embodiment, on the refrigerant flow direction DC side of the refrigerant cooling section 34. The refrigerant expansion section 36 expands the refrigerant C flowing through the refrigerant pipe 30, thereby cooling 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 of the refrigerant expansion section 36 (an inlet into which the refrigerant C is introduced) is connected to the refrigerant flow direction DC side of the position where the refrigerant compression section 32 (refrigerant cooling section 34) is provided on the refrigerant pipe 30. An outlet of the refrigerant expansion section 36 (an outlet from which the refrigerant C is discharged) is connected to the refrigerant pipe 30 on the opposite side (upstream side) from the position where the refrigerant compression section 32 is provided in the refrigerant flow direction DC.

[0026] The refrigerant expansion section 38 is connected to the refrigerant pipe 30 on the refrigerant flow direction DC side of the refrigerant compression section 32, and in this embodiment, on the refrigerant flow direction DC side of the refrigerant cooling section 34. The refrigerant expansion section 38 expands the refrigerant C flowing through the refrigerant pipe 30, thereby cooling the refrigerant C. The refrigerant expansion section 38 may be any mechanism capable of expanding the refrigerant C, and may be, 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 pipe 30. The inlet of the refrigerant expansion section 38 (the inlet through which refrigerant C is introduced) is connected to a location in the refrigerant flow direction DC between the position of the refrigerant cooling section 34 on the refrigerant pipe 30 and the position of the refrigerant expansion section 36 (more specifically, between the second feedstock cooling section 42 and the fourth feedstock cooling section 46, which will be described later). The outlet of the refrigerant expansion section 38 (the outlet from which refrigerant C is discharged) is connected to a location in the refrigerant flow direction DC between the position of the refrigerant expansion section 36 on the refrigerant pipe 30 and the position of the refrigerant compression section 32 (more specifically, between the fourth feedstock cooling section 46 and the second feedstock cooling section 42, which will be described later).

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

[0029] The raw material cooling unit 40 may include any number of raw material cooling units (heat exchangers), but in this embodiment, the raw material cooling unit 40 includes a first raw material cooling unit 41, a second raw material cooling unit 42, a third raw material cooling unit 44, and a fourth raw material cooling unit 46. Each raw material cooling unit will be described below.

[0030] (First raw material cooling section) The first raw material cooling section 41 is provided at a position closer to the raw material flow direction DH (downstream of the flow of the raw material gas HG) than the raw material supply section 12, and in contact with the raw material piping 10. The first raw material cooling section 41 is also provided at a position in contact with the nitrogen piping 22. The first raw material cooling section 41 cools the raw material gas HG by exchanging heat between the raw material gas HG flowing through the raw material piping 10 and the nitrogen gas NG flowing through the 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 Feedstock Cooling Section) The second feedstock cooling section 42 is provided at a position closer to the feedstock flow direction DH than the feedstock supply section 12 and in contact with the feedstock piping 10. The second feedstock cooling section 42 is also provided at a position in contact with the refrigerant piping 30. The second feedstock cooling section 42 cools the feedstock gas HG by exchanging heat between the feedstock gas HG flowing through the feedstock 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 closer to the feedstock flow direction DH than first feedstock cooling section 41. Second feedstock cooling section 42 is also provided in a location on refrigerant pipe 30, in the refrigerant flow direction DC, between the location of fourth feedstock cooling section 46 and the location of refrigerant compression section 32. 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 pipe 30 from fourth feedstock cooling section 46 in the refrigerant flow direction DC.

[0034] In this embodiment, second feedstock cooling unit 42 is provided in refrigerant flow direction DC at a location on refrigerant pipe 30 between the location of refrigerant cooling unit 34 and the location of fourth feedstock cooling unit 46. Therefore, second feedstock cooling unit 42 also cools refrigerant C that has been cooled by refrigerant cooling unit 34 using refrigerant C flowing through refrigerant pipe 30 from fourth feedstock cooling unit 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] (Third Feedstock Cooling Section) The third feedstock cooling section 44 is connected to the nitrogen pipe 20 and stores the liquid nitrogen NL supplied from the nitrogen pipe 20. A portion of the feedstock pipe 10 closer to the feedstock flow direction DH than the second feedstock cooling section 42 passes through the third feedstock cooling section 44. The third feedstock cooling section 44 exchanges heat between the stored liquid nitrogen NL and the feedstock gas HG passing through the feedstock pipe 10 within the third feedstock cooling section 44, thereby further cooling the feedstock gas HG cooled in the second feedstock cooling section 42 with the liquid nitrogen NL. The liquid nitrogen NL, whose temperature has been increased by the heat exchange, is vaporized and discharged to the nitrogen pipe 22 as nitrogen gas NG.

[0037] In this embodiment, the feed pipe 10 is connected to an ortho-para conversion catalyst 44A in the third feed cooling section 44. 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 feed gas HG passing through the feed pipe 10 in the third feed cooling section 44 is converted to para-hydrogen by coming into contact with the ortho-para conversion catalyst 44A. Furthermore, the feed 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] (Fourth feedstock cooling section) The fourth feedstock cooling section 46 is provided at a position closer to the feedstock flow direction DH than the feedstock supply section 12 and in contact with the feedstock piping 10. The fourth feedstock cooling section 46 is also provided at a position in contact with the refrigerant piping 30. The fourth feedstock cooling section 46 cools the feedstock gas HG by exchanging heat between the feedstock gas HG flowing through the feedstock piping 10 and the refrigerant C flowing through the refrigerant piping 30.

[0040] More specifically, in this embodiment, fourth feedstock cooling section 46 is provided closer to the feedstock flow direction DH than third feedstock cooling section 44. Furthermore, fourth feedstock cooling section 46 is provided at a location on refrigerant pipe 30, in refrigerant flow direction DC, between the position where refrigerant expansion section 36 is provided and the position where second feedstock cooling section 42 is provided. Therefore, fourth feedstock cooling section 46 further cools the feedstock gas HG, which has been 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 feedstock cooling section 46 is provided in refrigerant flow direction DC at a location on refrigerant pipe 30 between the location of second feedstock cooling section 42 and the location of refrigerant expansion section 36. Therefore, fourth feedstock cooling section 46 also cools refrigerant C that has undergone heat exchange in second feedstock cooling section 42 using refrigerant C flowing through refrigerant pipe 30 from refrigerant expansion section 36 in refrigerant flow direction DC.

[0042] In this embodiment, the feed pipe 10 is connected to the ortho-para conversion catalyst 46A even at a position where it contacts the fourth feed 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 feed gas HG passing through the feed pipe 10 is converted to para-hydrogen by contacting the ortho-para conversion catalyst 46A. Furthermore, the feed gas HG generates heat during ortho-para conversion, but by being cooled by the fourth feed 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] The raw material cooling unit 40 is not an essential component, and it is not essential that the raw material gas HG be cooled by the refrigerant C. The raw material gas HG may be cooled by at least the magnetic refrigeration unit 60.

[0045] (Raw material storage section) The raw material storage section 50 is connected to the raw material piping 10 closer to the raw material flow direction DH than the raw material cooling section 40, and in this embodiment, closer to the fourth raw material cooling section 46 in the raw material flow direction DH. The raw material storage section 50 is a container that temporarily stores the raw material gas HG after it has been cooled in the raw material cooling section 40. The raw material piping 10 is also provided with a raw material outlet section 50A that discharges the raw material gas HG stored in the raw material storage section 50 toward the raw material flow direction DH side of the raw material piping 10. The raw material outlet section 50A may be, for example, an on-off valve.

[0046] However, the raw material storage section 50 and the raw material discharge section 50A are not essential components. That is, for example, the raw material gas HG after being cooled in the raw material cooling section 40 may be supplied directly to the downstream magnetic refrigeration section 60 without being stored in the raw material storage section 50.

[0047] (Magnetic Refrigeration Unit) The magnetic refrigeration unit 60 is provided in the raw material piping 10 closer to the raw material flow direction DH than the raw material cooling unit 40, and in this embodiment, closer to the raw material flow direction DH than the raw material storage unit 50 and the raw material discharge unit 50A. The magnetic refrigeration unit 60 cools the raw material gas HG by a magnetic refrigeration method.

[0048] The magnetic refrigeration unit 60 has a magnetic body 62 and a magnet 64. The magnetic body 62 is provided in the raw material piping 10 on the raw material flow direction DH side of the raw material cooling unit 40 (in this embodiment, the raw material storage unit 50 and the raw material discharge unit 50A).

[0049] The magnetic body 62 is a member capable of adsorbing the source gas HG and whose temperature drops when the application of the magnetic field is stopped. The magnetic body 62 adsorbs the source gas HG by being cooled (the temperature drops), and is cooled (the temperature drops) by releasing the source gas HG. Furthermore, the temperature of the magnetic body 62 rises as the magnetic flux density (the degree of application of the magnetic field) increases, and drops as the magnetic flux density drops.

[0050] The material of the magnetic body 62 may be any material that is capable of adsorbing the source gas HG and whose temperature decreases as the magnetic flux density (degree of application of a magnetic field) decreases. For example, a porous metal oxide film (MOF) may be used as a material capable of adsorbing the source gas HG, such as copper benzene-1,3,5-tricarboxylate (Cu-BTC). Furthermore, a material that decreases in temperature as the magnetic flux density decreases may be, for example, a gadolinium compound. The magnetic body 62 may be composed of a hybrid material that combines a material capable of adsorbing the source gas HG with a material that decreases in temperature as the magnetic flux density decreases, or may be composed of a single material that is capable of adsorbing the source gas HG and whose temperature decreases as the magnetic flux density decreases.

[0051] Furthermore, the magnetic material 62 is preferably capable of promoting the conversion of ortho-hydrogen contained in the feed gas HG to para-hydrogen. That is, the magnetic material 62 preferably has the function of adsorbing the feed gas, the magnetic refrigeration function of decreasing the temperature as the magnetic flux density decreases, and also the function of an ortho-para conversion catalyst. The material of the magnetic material 62 may be any material that can adsorb the feed gas, decrease the temperature as the magnetic flux density decreases, and promote the conversion of ortho-hydrogen to para-hydrogen. For example, an MOF having a kagome lattice can be used as a material that can promote the conversion of ortho-hydrogen to para-hydrogen. For example, an MOF having a kagome lattice can be synthesized using Cu ions and an isophthalic acid derivative. The magnetic material 62 may be composed of a hybrid material that combines a material capable of adsorbing the feed gas HG, a material that decreases the temperature as the magnetic flux density decreases, and a material capable of promoting the conversion of ortho-hydrogen to para-hydrogen, or it may be composed of a single material that can adsorb the feed gas HG, decrease the temperature as the magnetic flux density decreases, and promote the conversion of ortho-hydrogen to para-hydrogen.

[0052] When the magnetic material 62 functions as an ortho-para conversion catalyst, an ortho-para conversion catalyst does not need to be provided in the raw material cooling section 40. In other words, the liquefaction apparatus 1 only needs to be provided with at least one ortho-para conversion catalyst in the liquefaction line, and furthermore, it does not need to be provided with an ortho-para conversion catalyst.

[0053] The magnet 64 is a member that applies a magnetic field to the magnetic body 62. The magnet 64 generates a magnetic field and may be an electromagnet or a permanent magnet. In the example of FIG. 1 , the magnet 64 is a ring-shaped electromagnet that is disposed so as to surround the magnetic body 62.

[0054] The method of cooling the raw material gas HG by the magnetic refrigeration unit 60 will be described in detail later.

[0055] (Magnetic Body Cooling Unit) The magnetic body cooling unit 70 is a mechanism that cools the magnetic body 62 with the refrigerant C. The magnetic body cooling unit 70 cools the magnetic body 62 by exchanging heat between the refrigerant C flowing through the refrigerant pipe 30 and the magnetic body 62.

[0056] The magnetic material cooling unit 70 is provided at a position where it contacts the magnetic material 62. The magnetic material cooling unit 70 is also provided at a location on the refrigerant pipe 30, in the refrigerant flow direction DC, between the position where the refrigerant expansion unit 36 ​​is provided and the position where the fourth raw material cooling unit 46 is provided. Therefore, the magnetic material cooling unit 70 cools the magnetic material 62 with the refrigerant C flowing through the refrigerant pipe 30 from the refrigerant expansion unit 36 ​​in the refrigerant flow direction DC.

[0057] In this manner, the magnetic material cooling section 70 cools the magnetic material 62 with the refrigerant C cooled in the refrigerant expansion section 36. Therefore, the magnetic material 62 can be cooled with the refrigerant C that has been cooled to the lowest temperature in the refrigerant line. In this embodiment, the refrigerant C that has cooled the magnetic material 62 pre-cools the raw material gas HG in the raw material cooling section 40. More specifically, the refrigerant C that has cooled the magnetic material 62 flows through 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 70. This allows the raw material gas HG and the magnetic material 62 to be efficiently cooled by the refrigerant C.

[0058] (Feedstock expansion section) The feedstock expansion section 80 is connected to the feedstock piping 10 on the feedstock flow direction DH side of the magnetic refrigeration section 60. The feedstock expansion section 80 expands the feedstock gas HG that has been cooled in the magnetic refrigeration section 60 but remains unliquefied, thereby cooling the feedstock gas HG and producing liquid HL. The liquid HL produced by the feedstock expansion section 80 is introduced from the feedstock piping 10 into the liquid storage section 14 and stored in the liquid storage section 14. The feedstock expansion section 80 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.

[0059] The position of the raw material expansion section 80 does not necessarily have to be closer to the raw material flow direction DH than the magnetic refrigeration section 60, and may be located on the opposite side of the magnetic refrigeration section 60 from the raw material flow direction DH (between the raw material cooling section 40 and the magnetic refrigeration section 60). In this case, the raw material expansion section 80 may expand and cool the raw material gas HG cooled in the raw material cooling section 40, and the magnetic refrigeration section 60 may cool and liquefy the raw material gas HG that remains unliquefied after being cooled in the raw material expansion section 80. The raw material expansion section 80 may be located both closer to the raw material flow direction DH than the magnetic refrigeration section 60 and on the opposite side of the magnetic refrigeration section 60 from the raw material flow direction DH.

[0060] However, the raw material expansion section 80 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 may be liquefied only by the magnetic refrigeration section 60.

[0061] (Liquefaction Method) A flow chart will be described below of the method for liquefying the raw material gas HG using the above-described liquefaction apparatus 1. Fig. 2 is a flowchart for explaining the method for liquefying the raw material gas.

[0062] (Cooling by Feedstock Cooling Unit) As shown in FIG. 2 , in this method, the feedstock cooling unit 40 cools the feedstock gas HG with the refrigerant C (step S10). In this step, the controller 100 controls the feedstock supply unit 12 to supply the feedstock gas HG into the feedstock piping 10. In this case, for example, the controller 100 may control the valve of the feedstock supply unit 12 to supply the feedstock gas HG from the feedstock supply unit 12. The controller 100 also controls the nitrogen supply unit 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 unit 24 to supply the liquid nitrogen NL from the nitrogen supply unit 24. The controller 100 also operates the refrigerant compression unit 32, the refrigerant cooling unit 34, and the refrigerant expansion units 36 and 38 to circulate the refrigerant C through the refrigerant piping 30. As a result, the feedstock gas HG flows through the feedstock piping 10 along the feedstock flow direction DH while being cooled by the feedstock cooling unit 40. Specifically, the feed gas HG is cooled in the first feed cooling section 41 by nitrogen gas NG flowing through the nitrogen pipe 22. The feed gas HG cooled in the first feed cooling section 41 is further cooled in the second feed cooling section 42 by refrigerant C flowing through refrigerant pipe 30. The feed gas HG cooled in the second feed cooling section 42 is then cooled by liquid nitrogen NL while undergoing ortho-para conversion in the third feed cooling section 44. The feed gas HG cooled in the third feed cooling section 44 is then cooled in the fourth feed cooling section 46 by refrigerant C while undergoing ortho-para conversion. The feed gas HG cooled in the fourth feed cooling section 46 is stored in the feed storage section 50.

[0063] (Adsorption of Source Gas) Next, in this method, the magnetic body 62 is cooled while a magnetic field is applied to the magnetic body 62, and the source gas HG cooled in the source cooling unit 40 is adsorbed by the magnetic body 62 (step S12). Hereinafter, a method for adsorbing the source gas HG to the magnetic body 62 will be described with reference to Fig. 3. Fig. 3 is a schematic diagram illustrating the adsorption of the source gas.

[0064] When the source gas HG is adsorbed to the magnetic body 62, as shown in step S12A of FIG. 3 , the supply of the source gas HG to the magnetic body 62 is stopped, and a magnetic field is applied from the magnet 64 to the magnetic body 62. For example, the control device 100 controls the source gas discharge unit 50A (for example, by closing a valve) to stop the supply of the source gas HG stored in the source gas storage unit 50 to the magnetic body 62. Then, the control device 100 applies a magnetic field from the magnet 64 to the magnetic body 62, and the supply of the source gas HG to the magnetic body 62 is stopped. The magnetic body 62 is heated by the application of the magnetic field, and its temperature increases. Note that any method may be used to apply a magnetic field from the magnet 64 to the magnetic body 62. For example, a voltage may be applied to the magnet 64, which is an electromagnet, or the distance between the magnet 64, which is a permanent magnet, and the magnetic body 62 may be reduced.

[0065] In step S12A, with a magnetic field applied to the magnetic body 62, the magnetic body cooling unit 70 exchanges heat between the refrigerant C flowing through the refrigerant pipe 30 and the magnetic body 62. This cools (discharges heat from) the magnetic body 62 that has been heated by the application of the magnetic field.

[0066] 3 , the source gas HG is supplied to the cooled magnetic body 62 while a magnetic field is applied, causing the magnetic body 62 to adsorb the source gas HG. For example, the control device 100 controls the source gas discharge unit 50A (for example, by opening a valve) to supply the source gas HG stored in the source gas storage unit 50 to the magnetic body 62. The magnetic body 62 adsorbs the source gas HG because it is cooled by the magnetic body cooling unit 70. Note that the magnetic body cooling unit 70 cools the magnetic body 62 even while the magnetic body 62 is adsorbing the source gas HG, i.e., while the source gas HG is being supplied to the magnetic body 62. This makes it possible to suppress a temperature rise in the magnetic body 62 due to adsorption of the source gas HG.

[0067] The amount of source gas HG adsorbed to the magnetic body 62 when a magnetic field is applied may be arbitrary. For example, the control device 100 may supply the source gas HG from the source material reservoir 50 to the magnetic body 62 until the internal pressure of the source material reservoir 50 (the pressure of the source gas HG stored in the source material reservoir 50) drops by approximately 0.3 MPa or more and 0.8 MPa or less (preferably 0.5 MPa). That is, for example, if the internal pressure of the source material reservoir 50 before the supply of the source gas HG is 1 MPa, the source gas HG may be supplied from the source material reservoir 50 to the magnetic body 62 until the internal pressure of the source material reservoir 50 reaches 0.5 MPa.

[0068] (Cooling of Source Gas) Once the source gas HG has been adsorbed by the magnetic body 62, as shown in Fig. 2, the application of the magnetic field to the magnetic body 62 is stopped, and the source gas HG adsorbed by the magnetic body 62 is further cooled (step S14). A method for cooling the adsorbed source gas HG will be described below with reference to Fig. 4. Fig. 4 is a schematic diagram illustrating the cooling of the adsorbed source gas.

[0069] 4, once the source gas HG is adsorbed to the magnetic body 62 with the magnetic field applied thereto, the application of the magnetic field to the magnetic body 62 is stopped. For example, the control device 100 controls the magnet 64 to stop the application of the magnetic field from the magnet 64 to the magnetic body 62. Note that any method may be used to stop the application of the magnetic field to the magnetic body 62, and the method may include stopping the application of a voltage to the magnet 64, which is an electromagnet, or increasing the distance between the magnet 64, which is a permanent magnet, and the magnetic body 62.

[0070] In this embodiment, it is preferable to stop applying the magnetic field to the magnetic body 62 while the source gas HG is being supplied from the source gas reservoir 50 to the magnetic body 62. When the magnetic field is removed, the temperature of the magnetic body 62 decreases, and the magnetic body 62 can further adsorb the source gas HG.

[0071] The amount of source gas HG adsorbed to the magnetic body 62 when the application of the magnetic field is stopped may be arbitrary. For example, the control device 100 may supply the source gas HG from the source material reservoir 50 to the magnetic body 62 until the internal pressure of the source material reservoir 50 (the pressure of the source gas HG stored in the source material reservoir 50) drops by approximately 0.1 MPa or more and 0.5 MPa or less (preferably 0.3 MPa). That is, for example, if the internal pressure of the source material reservoir 50 before the application of the magnetic field is stopped is 0.5 MPa, the control device 100 may supply the source gas HG from the source material reservoir 50 to the magnetic body 62 until the internal pressure of the source material reservoir 50 reaches 0.2 MPa.

[0072] Next, as shown in step S14B of FIG. 4 , the supply of the source gas HG to the magnetic body 62 with the magnetic field applied thereto is stopped. For example, the control device 100 controls the source gas outlet 50A (for example, by closing a valve) to stop the supply of the source gas HG stored in the source gas storage unit 50 to the magnetic body 62. Since the application of the magnetic field has been stopped, the temperature of the magnetic body 62 decreases, and the adsorbed source gas HG is cooled. Note that the magnetic body 62 preferably cools the source gas HG to a temperature of, for example, −250° C. or less.

[0073] The source gas HG cooled by the magnetic body 62 is released from the magnetic body 62 in the source gas flow direction DH. The release of the source gas HG further cools the magnetic body 62.

[0074] A plurality of magnetic refrigeration units 60 may be provided. In this case, for example, each magnetic refrigeration unit 60 may be connected in parallel to the raw material pipe 10. This allows each magnetic refrigeration unit 60 (magnetic body 62) to alternately adsorb the raw material gas HG and cool the raw material gas HG, thereby allowing the raw material gas HG to be continuously cooled.

[0075] The raw material gas HG released from the magnetic body 62 is supplied to the raw material expansion section 80 and expanded by the raw material expansion section 80. The raw material gas HG expanded in the raw material expansion section 80 is further cooled and liquefied, and is introduced into the liquid storage section 14 as the liquid HL and stored therein.

[0076] The magnetic refrigeration unit 60 (magnetic body 62) may cool the raw material gas HG to a degree that does not liquefy the raw material gas HG, may cool the raw material gas HG to a degree that liquefies at least a portion of the raw material gas HG, or may cool the raw material gas HG to a degree that liquefies all of the raw material gas HG. When the magnetic body 62 liquefies all of the raw material gas HG, the raw material expansion unit 80 does not need to be provided.

[0077] As described above, in this embodiment, the source gas HG is adsorbed onto the magnetic body 62, and the application of a magnetic field to the magnetic body 62 that has adsorbed the source gas HG is stopped to cool the magnetic body 62, thereby cooling the adsorbed source gas HG. According to this embodiment, the use of magnetic refrigeration improves the liquefaction efficiency of the source gas HG. Furthermore, in this embodiment, the adsorbed source gas HG is released from the magnetic body 62. In the process of releasing the source gas HG, the magnetic body 62 is further cooled, thereby more efficiently cooling the source gas HG. Furthermore, in this embodiment, the source gas HG, after being pre-cooled with the refrigerant C, is cooled in the magnetic refrigeration unit 60 and expanded in the source expansion unit 48. Thus, by cooling the source gas HG in two steps, expansion and magnetic refrigeration, the liquefaction efficiency can be more efficiently improved. Furthermore, in this embodiment, the magnetic body 62 of the magnetic refrigeration unit 60 is cooled with the refrigerant C used to pre-cool the source gas HG. Therefore, it is possible to efficiently perform the refrigeration cycle of the magnetic body 62 and pre-cool the raw material gas HG.

[0078] (Effects) As described above, the liquefaction apparatus 1 according to the first aspect of the present disclosure includes the raw material pipe 10 through which the raw material gas HG flows, the magnetic body 62 connected to the raw material pipe 10 and capable of adsorbing the raw material gas HG supplied from the raw material pipe 10, and whose temperature decreases when the application of the magnetic field is stopped, and the magnet 64 that applies a magnetic field to the magnetic body 62. When the magnet 64 stops applying the magnetic field to the magnetic body 62 while the magnetic body 62 is in a state in which the magnetic body 62 has adsorbed the raw material gas HG, the magnetic body 62 cools the adsorbed raw material gas HG. According to the present disclosure, the use of magnetic refrigeration can improve the liquefaction efficiency of the raw material gas HG.

[0079] A liquefaction apparatus 1 according to a second aspect of the present disclosure is the liquefaction apparatus according to the first aspect, further including a magnetic body cooling unit 70 that cools the magnetic body 62, and the magnetic body cooling unit 70 cools the magnetic body 62 while a magnetic field is applied from the magnet 64 to the magnetic body 62, thereby causing the magnetic body 62 to adsorb the source gas HG. According to the present disclosure, the source gas HG is adsorbed to the magnetic body 62 by discharging heat from the magnetic body 62 to which the magnetic field is applied, and the source gas HG is released from the magnetic body 62 while the application of the magnetic field is stopped. This allows the adsorption of the source gas HG and the cooling of the source gas HG to be performed in an optimal manner, thereby improving the efficiency of liquefying the source gas HG.

[0080] The liquefaction apparatus 1 according to a third aspect of the present disclosure is the liquefaction apparatus according to the first or second aspect, and further includes a raw material expansion section 80 that is provided at least either upstream or downstream of the magnetic body 62 in the flow (raw material flow direction DH) of the raw material gas HG in the raw material piping 10, and that expands and liquefies the raw material gas HG. In this way, by cooling the raw material gas HG through a two-stage process of expansion and magnetic refrigeration, the liquefaction efficiency can be more suitably improved.

[0081] A liquefaction apparatus 1 according to a fourth aspect of the present disclosure is the liquefaction apparatus according to the third aspect, and uses a two-phase expansion turbine or a Joule-Thomson valve as the feed expansion section 80. According to the present disclosure, the feed gas HG can be appropriately expanded, thereby more suitably improving the liquefaction efficiency.

[0082] The liquefaction apparatus 1 according to a fifth aspect of the present disclosure is the liquefaction apparatus according to any one of the first to fourth aspects, and further includes a raw material cooling section 40 that is provided upstream of the magnetic body 62 in the flow of the raw material gas HG in the raw material piping 10 and cools the raw material gas HG with a refrigerant C. According to the present disclosure, the raw material gas HG that has been pre-cooled with the refrigerant C is cooled by the magnetic body 62, and therefore the liquefaction efficiency can be more suitably improved.

[0083] 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.

[0084] A liquefaction apparatus 1 according to a seventh aspect of the present disclosure is the liquefaction apparatus according to the sixth aspect, in which the magnetic body 62 can promote the conversion of ortho-hydrogen contained in the feed gas HG to para-hydrogen. By providing the magnetic body 62 with the function of an ortho-para conversion catalyst, hydrogen can be more appropriately liquefied.

[0085] A liquefaction method according to an eighth aspect of the present disclosure includes the steps of: adsorbing the source gas HG to a magnetic body 62 that is capable of adsorbing the source gas HG and whose temperature decreases when application of a magnetic field is stopped; and stopping application of the magnetic field to the magnetic body 62 while the magnetic body 62 has adsorbed the source gas HG, thereby cooling the adsorbed source gas HG by the magnetic body 62. According to the present disclosure, the liquefaction efficiency of the source gas HG can be improved.

[0086] A liquefaction method according to a ninth aspect of the present disclosure is the liquefaction method according to the eighth aspect, wherein in the step of adsorbing the source gas HG, the magnetic body 62 is cooled while a magnetic field is applied to the magnetic body 62, thereby adsorbing the source gas HG to the magnetic body 62. This allows the adsorption of the source gas HG and the cooling of the source gas HG to be performed in an optimal manner, thereby improving the efficiency of liquefying the source gas HG.

[0087] Although the embodiments of the present disclosure have been described above, the embodiments are not limited to the contents of these embodiments. Furthermore, the above-described components include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the above-described components can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the above-described embodiments.

[0088] REFERENCE SIGNS LIST 1 Liquefaction apparatus 10 Raw material piping 12 Raw material supply section 14 Liquid storage section 20, 22 Nitrogen piping 24 Nitrogen supply section 30 Refrigerant piping 32 Refrigerant compression section 34 Refrigerant cooling section 36, 38 Refrigerant expansion section 40 Raw material cooling section 50 Raw material storage section 60 Magnetic refrigeration section 62 Magnetic material 64 Magnet 70 Magnetic material cooling section 80 Raw material expansion section HG Raw material gas HL Liquid

Claims

1. A liquefaction apparatus comprising: a raw material pipe through which a raw material gas flows; a magnetic body connected to said raw material pipe and capable of adsorbing the raw material gas supplied from said raw material pipe, the temperature of which decreases when application of a magnetic field is stopped; and a magnet that applies a magnetic field to said magnetic body, wherein said magnet stops application of the magnetic field to said magnetic body while said magnetic body has adsorbed the raw material gas, thereby causing said magnetic body to cool the adsorbed raw material gas.

2. A liquefaction apparatus as described in claim 1, further comprising a magnetic material cooling unit that cools the magnetic material, the magnetic material cooling unit cooling the magnetic material while a magnetic field is applied from the magnet to the magnetic material, thereby causing the raw material gas to be adsorbed by the magnetic material.

3. A liquefaction apparatus as described in claim 1 or claim 2, further comprising a raw material expansion section provided at least on the upstream or downstream side of the magnetic body in the flow of the raw material gas within the raw material piping, which expands the raw material gas and liquefies the raw material gas.

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

5. A liquefaction apparatus as described in claim 1 or claim 2, further comprising a raw material cooling section that is provided upstream of the magnetic body in the flow of the raw material gas in the raw material piping and cools the raw material gas with a refrigerant.

6. A liquefaction apparatus according to claim 1 or 2, wherein the raw material gas is hydrogen gas.

7. The liquefaction apparatus according to claim 6, wherein the magnetic material is capable of promoting the conversion of ortho-hydrogen contained in the feed gas into para-hydrogen.

8. A liquefaction method comprising: a step of adsorbing a source gas into a magnetic material capable of adsorbing the source gas and whose temperature drops when application of a magnetic field is stopped; and a step of cooling the adsorbed source gas by the magnetic material by stopping application of a magnetic field to the magnetic material while the magnetic material has adsorbed the source gas.

9. A liquefaction method as described in claim 8, wherein in the step of adsorbing the source gas, the magnetic body is cooled while a magnetic field is applied to the magnetic body, thereby adsorbing the source gas to the magnetic body.

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