Double pipe for liquefaction gas transfer

Abstract

To support thrust generated in an inner pipe without causing radial displacement due to heat shrinkage in a bent pipe part of the inner pipe with a simple structure in a double pipe for liquefaction gas transfer including the bent pipe part.SOLUTION: A double pipe (1) for liquefaction gas transfer includes an inner pipe (3) for making a liquefaction gas pass through, and an outer pipe (5) for forming a vacuum insulation layer (7) between the inner pipe and itself. The inner pipe (3) is a double pipe including a first a straight pipe part (9) extending in a first direction (X1) and supported in a displaceable manner in the first direction, a second straight pipe part (11) extending in a second direction (X2) different from the first direction (X1) and supported in a displaceable manner in the second direction, and a bent pipe part (13) for connecting the first straight pipe part and the second straight pipe part, and includes a first inner pipe axis direction support member (21) and a second inner pipe axis direction support member (23) formed from a heat insulation material and respectively provided on an axial center (C1) of the first straight pipe part (9) and an axial center (C2) of the second straight pipe part (11) between the bent pipe part (13) and the outer pipe (5).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a double pipe used for transporting liquefied gas. [Background technology]

[0002] In general, it has been proposed to use a double-walled vacuum insulated pipe as a pipe for transporting a cryogenic fluid such as a liquefied gas (see, for example, Patent Document 1). A thrust is generated in the inner pipe through which the low-temperature liquefied gas passes when pressure is applied from the internal fluid. In general, one of the structures for suppressing the movement of the inner pipe due to such a thrust is to provide a support member against the thrust between the outer pipe and the inner pipe in the straight pipe section of the double walled pipe, thereby restricting the axial movement of the inner pipe relative to the outer pipe. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-64652 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in a double pipe including a curved pipe section, if thrust support members that limit the axial movement of the inner pipe are provided on the straight pipe sections in each direction, the section including the curved pipe section of the inner pipe sandwiched between the two thrust support members will not be able to absorb the thermal contraction in the axial direction, and the straight pipe sections will be pulled toward each other in the radial direction, causing the curved pipe section in that section to be displaced inward. This displacement applies a large reaction force to the inner pipe support members, such as the spacers that support the inner pipe, and as a result, the position and method for installing the inner pipe support members will be restricted.

[0005] In order to solve the above-mentioned problems, the object of the present disclosure is to support the thrust generated in the inner pipe in a double piping for transporting liquefied gas including a curved pipe section with a simple structure without causing radial displacement due to thermal contraction in the curved pipe section of the inner pipe. [Means for solving the problem]

[0006] In order to solve the above problems, the double pipe for transporting liquefied gas according to the present disclosure comprises: an inner pipe through which a liquefied gas passes; and an outer pipe covering the outside of the inner pipe and forming a vacuum insulation layer between the inner pipe and an outer pipe; The inner tube is The pipe has a first straight pipe section extending in a first direction and supported so as to be displaceable in the first direction, a second straight pipe section extending in a second direction different from the first direction and supported so as to be displaceable in the second direction, and a curved pipe section connecting the first straight pipe section and the second straight pipe section. A double pipe, a first inner pipe axial direction support member made of a heat insulating material and provided on the axis of the first straight pipe portion between the curved pipe portion and the outer pipe; a second inner pipe axial direction support member made of a heat insulating material and provided on the axis of the second straight pipe portion between the curved pipe portion and the outer pipe; Equipped with. Effect of the Invention

[0007] According to the double piping for transporting liquefied gas disclosed herein, in a double piping for transporting liquefied gas including a curved pipe section, a thrust force generated in the inner pipe can be supported with a simple structure without causing radial displacement due to thermal contraction in the curved pipe section of the inner pipe. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a vertical cross-sectional view that illustrates a schematic configuration of a double pipe for transporting liquefied gas according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a vertical cross-sectional view that illustrates a schematic configuration of a double pipe for transporting a liquefied gas according to a modified example of the embodiment of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 shows a double pipe 1 for transferring liquefied gas according to one embodiment of the present disclosure. In the following description, this pipe 1 for transferring liquefied gas will simply be referred to as "double pipe 1". The double pipe 1 is configured as a vacuum insulated pipe having a double structure. That is, the double pipe 1 is configured of an inner pipe 3 through which liquefied gas passes and an outer pipe 5 that covers the outside of the inner pipe 3. A vacuum insulation layer 7 is formed in the radial gap between the inner pipe 3 and the outer pipe 5. The inner pipe 3 and the outer pipe 5 are made of a metal material such as stainless steel. However, the material of the inner pipe 3 and the outer pipe 5 is not limited to stainless steel.

[0010] The double pipe 1 is used in a liquefied gas storage facility such as a liquefied gas storage ship or an onshore liquefied gas storage base. In this specification, the term "liquefied gas storage ship" refers to a ship having a function of storing liquefied gas. In addition to liquefied gas carriers, liquefied gas storage ships include, for example, liquefied gas fuel ships and bunkering ships that supply liquefied gas to other ships. However, the liquefied gas storage facility is not limited to a ship as long as it has a structure and function for storing liquefied gas, and may be, for example, a ground-based liquefied gas storage facility or a plant that uses liquefied gas.

[0011] The liquefied gas transferred by the double pipe 1 is, for example, ammonia (LNH3, about -30°C), liquefied petroleum gas (LPG, about -45°C), liquefied carbon dioxide (LCO2, about -80°C), liquefied ethylene gas (LEG, about -100°C), liquefied natural gas (LNG, about -160°C), liquefied nitrogen (LN2, about -200°C), liquefied hydrogen (LH2, about -250°C), and liquefied helium (LHe, about -270°C). In this embodiment, liquefied hydrogen is transferred through the double pipe 1.

[0012] In this embodiment, as shown in FIG. 1, the inner pipe 3 has a first straight pipe section 9, a second straight pipe section 11 extending in a direction different from the first straight pipe section 9, and a curved pipe section 13 connecting the first straight pipe section 9 and the second straight pipe section 11. The first straight pipe section 9 and a portion of the outer pipe 5 covering the first straight pipe section 9 are arranged concentrically, i.e., so as to have the same first axis C1. The second straight pipe section 11 and a portion of the outer pipe 5 covering the second straight pipe section 11 are arranged concentrically, i.e., so as to have the same second axis C2. In this specification, the direction in which the first straight pipe section 9 extends is referred to as the "first direction X1", and the direction in which the second straight pipe section 11 extends is referred to as the "second direction X2". The first direction X1 is parallel to the first axis C1, and the second direction X2 is parallel to the second axis C2. In the illustrated example, the angle between the first direction X1 and the second direction X2 is approximately 90°, but the angle between the first direction X1 and the second direction X2 does not have to be 90°. In addition, the radial direction of the first straight pipe portion of the double pipe 1 is simply referred to as the "first radial direction", and the radial direction of the second straight pipe portion is simply referred to as the "second radial direction".

[0013] The first straight pipe section 9 is supported so as to be displaceable in a first direction X1, and the second straight pipe section 11 is supported so as to be displaceable in a second direction X2. Specifically, in this embodiment, the first straight pipe section 9 and the second straight pipe section 11 are supported so as to be displaceable in the first and second directions X1 and X2, respectively, by a spacer 15 provided between the outer peripheral surface of the inner pipe 3 and the inner peripheral surface of the outer pipe 5. The spacer 15 restricts the movement of the first straight pipe section 9 in the first radial direction and the movement of the second straight pipe section 11 in the second radial direction. In this embodiment, the spacer 15 is formed of a heat insulating material.

[0014] The first straight pipe section 9 and the second straight pipe section 11 each include an expansion / contraction allowing section 17 that allows a change in the axial length. In this embodiment, each straight pipe section 9, 11 has a bellows as the expansion / contraction allowing section 17. With this configuration, the expansion / contraction allowing section 17 can absorb the thermal contraction difference between the outer pipe 5 and the inner pipe 3, and suppress the load acting on the first inner pipe axial direction support member 21 and the second inner pipe axial direction support member 23. Note that the expansion / contraction allowing section 17 may be configured to allow, for example, radial displacement in addition to the change in the axial length of the inner pipe 3. Also, the expansion / contraction allowing section 17 may be provided in only one of the first straight pipe section 9 and the second straight pipe section 11, or may be omitted.

[0015] As shown in FIG. 1, between the curved pipe section 13 and the outer pipe 5, a first inner pipe axial support member 21 is provided on the first axis C1, and a second inner pipe axial support member 23 is provided on the second axis C2. The first inner pipe axial support member 21 supports a thrust force in one direction along the first axis C1 generated by the extension of the expansion and contraction allowable section 17 of the first straight pipe section 9 through which the liquefied gas passes. The second inner pipe axial support member 23 supports a thrust force in one direction along the second axis C2 generated by the extension of the expansion and contraction allowable section 17 of the second straight pipe section 11 through which the liquefied gas passes. In this embodiment, the first inner pipe axial support member 21 and the second inner pipe axial support member 23 are integrated to form a common inner pipe axial support member 25. This configuration makes it possible to reduce the number of parts and the number of steps for installing the support member. However, as shown as a modified example in FIG. 2, the first inner pipe axial support member 21 and the second inner pipe axial support member 23 may be formed separately.

[0016] The first inner pipe axial support member 21 and the second inner pipe axial support member 23 are made of a heat insulating material. By making these inner pipe axial support members 21, 23 from a heat insulating material, heat transfer between the inner pipe 3 and the outer pipe 5 can be suppressed. The inner pipe axial support members 21, 23 may be at least partially made of a heat insulating material, and may be composed of, for example, a base fixed to the inner circumferential surface 5a of the outer pipe 5 and a heat insulating material fixed to the inner pipe side part of the base. The first inner pipe axial support member 21 and the second inner pipe axial support member 23 can be formed, for example, by welding a rib to the inner surface of the outer pipe and then fixing the heat insulating material constituting these support members to the rib with a bolt. However, the installation method of the first inner pipe axial support member 21 and the second inner pipe axial support member 23 is not limited to this.

[0017] For example, glass fiber reinforced plastic (GFRP) can be used as the insulating material used for the inner pipe axial support members 21, 23. The spacer 15 that restrains radial movement between the inner pipe 3 and the outer pipe 5 may also be made of glass fiber reinforced plastic (GFRP). However, the insulating material used to form these members is not limited to this example, and any high-strength insulating material that does not release gas under vacuum may be used, and other than GFRP, for example, polytetrafluoroethylene (PTFE), polyether ether ketone (PEEK), ultra-high molecular weight polyethylene (UHMWPE), etc. can be used.

[0018] In the present embodiment shown in Fig. 1, the corner portion 27, which is the portion of the outer pipe 5 that covers the curved pipe portion 13, is formed as a miter bend with a butt angle of approximately 90°. However, the corner portion 27 of the outer pipe 5 is not limited to this, and may be a miter bend with a different butt angle, or may be a simple curved pipe, elbow, or the like, depending on the thrust force acting and design requirements, etc. Furthermore, as a method for joining two or more pipes that form a corner portion, the pipes may be butted together to be joined, or they may be connected as a lap joint in which pipes, plate materials, etc. are overlapped.

[0019] In this embodiment, as shown in FIG. 1, the first inner pipe axial support member 21 and the second inner pipe axial support member 23 have shapes that match the shapes of the curved pipe portion 13 and the corner portion 27. Specifically, in the illustrated example, the surfaces of both inner pipe axial support members 21, 23 that contact the curved pipe portion 13 have a shape that follows the curved shape of the outer part of the curved pipe portion 13, and the surfaces that contact the corner portion 27 have a shape that follows the curved shape of the inner surface of the corner portion 27. By adopting such shapes, the first inner pipe axial support member 21 and the second inner pipe axial support member 23 can receive thrust in each direction in a distributed manner, and can support the thrust more stably. The shapes and dimensions of the first inner pipe axial support member 21 and the second inner pipe axial support member 23 may be appropriately changed depending on, for example, the magnitude of the thrust to be supported, design conditions, etc. For example, when the generated thrust is small, the first inner pipe axial support member 21 and the second inner pipe axial support member 23 may be plate-like members that do not match the shapes of the curved pipe portion 13 and the corner portion 27.

[0020] In this embodiment, a reinforcing member 29 is provided on the outside of the corner portion 27 of the outer pipe 5. As the reinforcing member 29, for example, a rib can be provided on the outside of the outer pipe 5 by welding or the like. By providing such a reinforcing member 29, the strength of the corner portion 27 can be maintained even if the shape of the outer pipe 5 is changed to provide the inner pipe axial direction support members 21, 23. In the illustrated example, the reinforcing members 29 are provided separately at positions on the extension lines of the first straight pipe portion 9 and the second straight pipe portion 11 in the corner portion 27, but these reinforcing members 29 may be provided as an integrated member. However, the reinforcing member 29 may be omitted.

[0021] The double pipe 1 according to the first aspect of the present embodiment described above includes an inner pipe 3 through which a liquefied gas passes, and an outer pipe 5 that covers the outside of the inner pipe 3 and forms a vacuum insulation layer 7 between the inner pipe 3 and the outer pipe 5. The inner tube 3 is A double pipe 1 having a first straight pipe section 9 extending in a first direction X1 and supported so as to be displaceable in the first direction X1, a second straight pipe section 11 extending in a second direction X2 different from the first direction X1 and supported so as to be displaceable in the second direction X2, and a curved pipe section 13 connecting the first straight pipe section 9 and the second straight pipe section 11, a first inner pipe axial direction support member 21 made of a heat insulating material and provided on the axis C1 of the first straight pipe portion 9 between the curved pipe portion 13 and the outer pipe 5; a second inner pipe axial direction support member 23 made of a heat insulating material and provided on the axis C2 of the second straight pipe portion 11 between the curved pipe portion 13 and the outer pipe 5; According to this configuration, the first inner pipe axial support member 21 and the second inner pipe axial support member 23 can support a thrust in one direction along the first axis C1 and a thrust in one direction along the second axis C2, which are generated by the expansion of the expansion-and-contraction allowable portion 17 of the first straight pipe portion 9 and the second straight pipe portion 11 through which the liquefied gas passes. Unlike conventional thrust support members, the first inner pipe axial support member 21 and the second inner pipe axial support member 23 support the thrust generated in the inner pipe 3 on the outside of the curved pipe portion, and do not hinder the axial movement of the straight pipe portions 9, 11 relative to the outer pipe 5 caused by the expansion of the expansion-and-contraction allowable portion 17. As a result, even if thermal contraction occurs in the inner pipe 3, it can be absorbed by the expansion-and-contraction allowable portion 17, so that the straight pipe portions 9, 11 are not pulled radially toward each other around the curved pipe portion 13, and the corresponding portion is not displaced toward the inside of the curved pipe portion. In this manner, with the above-described simple structure, the thrust force generated in the inner tube 3 can be supported without causing radial displacement of the curved tube portion 13 of the inner tube 3 due to thermal contraction.

[0022] The double pipe 1 according to the second aspect of the present embodiment is the double pipe according to the first aspect, in which the first inner pipe axial support member 21 and the second inner pipe axial support member 23 are integrally formed. This configuration makes it possible to reduce the number of parts and the number of steps for installing the support members.

[0023] The double pipe 1 according to the third aspect of this embodiment is the double pipe according to the first or second aspect, in which a reinforcing member 29 is provided on the outside of a portion of the outer pipe 5 that covers the curved pipe portion 13. According to this configuration, by providing such a reinforcing member 29, the strength of the corner portion 27 can be maintained even when the shape of the outer pipe 5 is changed in order to provide the inner pipe axial support members 21, 23.

[0024] The double pipe 1 according to the fourth aspect of this embodiment is the double pipe according to any one of the first to third aspects, in which at least one of the first straight pipe section 9 and the second straight pipe section 11 includes an expansion / contraction allowing section 17 that allows a change in axial length. According to this configuration, the expansion / contraction allowing section 17 absorbs the thermal contraction difference between the outer pipe 5 and the inner pipe 3, and the load acting on the first inner pipe axial support member 21 and the second inner pipe axial support member 23 can be suppressed.

[0025] The double pipe 1 according to the fifth aspect of this embodiment is the double pipe according to any one of the first to fourth aspects, in which the first inner pipe axial support member 21 and the second inner pipe axial support member 23 have a shape that matches the shape of the curved pipe portion 13. According to this configuration, the first inner pipe axial support member 21 and the second inner pipe axial support member 23 can receive thrust in each direction in a distributed manner, and can support the thrust more stably.

[0026] As described above, the preferred embodiment of the present disclosure has been described with reference to the drawings, but various additions, modifications, and deletions are possible without departing from the spirit of the present disclosure. Therefore, such additions, modifications, and deletions are also included in the scope of the present disclosure. [Explanation of symbols]

[0027] 1. Double piping for transporting liquefied gas 3 Inner tube 5 Outer tube 7 1st straight pipe section 9 2nd straight pipe section 11 Bent pipe section 13 Vacuum insulation layer 15 Spacer 17 Elasticity allowance section 21 First inner tube axial support member 23 second inner tube axial support member 25 Common inner tube axial support member 27 Corner section 29 Reinforcement members C1 First axis C2 Second axis X1 First direction X2 Second direction

Claims

1. an inner pipe through which a liquefied gas passes; and an outer pipe covering the outside of the inner pipe and forming a vacuum insulation layer between the inner pipe and an outer pipe; The inner tube is The pipe has a first straight pipe section extending in a first direction and supported so as to be displaceable in the first direction, a second straight pipe section extending in a second direction different from the first direction and supported so as to be displaceable in the second direction, and a curved pipe section connecting the first straight pipe section and the second straight pipe section. A double pipe, a first inner pipe axial direction support member made of a heat insulating material and provided on an axis of the first straight pipe portion between the curved pipe portion and the outer pipe; a second inner pipe axial direction support member made of a heat insulating material and provided on the axis of the second straight pipe portion between the curved pipe portion and the outer pipe; A double piping for transferring liquefied gas.

2. 2. The double pipe according to claim 1, wherein the first inner pipe axial support member and the second inner pipe axial support member are integrally formed. Double piping for transporting liquefied gas.

3. 3. The double pipe according to claim 1, wherein a reinforcing member is provided on the outer pipe at a portion covering the bent pipe portion. Double piping for transporting liquefied gas.

4. The double pipe according to claim 1 or 2, At least one of the first straight pipe section 9 and the second straight pipe section 11 includes an expansion / contraction allowing section that allows a change in axial length. Double piping for transporting liquefied gas.

5. 3. The double pipe according to claim 1, wherein the first inner pipe axial support member and the second inner pipe axial support member have a shape that matches a shape of the curved pipe portion. Double piping for transporting liquefied gas.

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