Piping structure for cryogenic liquid and ship equipped with same

Abstract

To provide a cryogenic liquid pipe structure that can restrain a structural material of a ship from being made brittle by an effect of drops of liquefied air formed on a surface of a pipe through which cryogenic liquid flows, in association with a decrease in temperature of the pipe, and the ship comprising the same.SOLUTION: A cryogenic liquid pipe structure is applied to a ship for storing cryogenic liquid with a boiling point of -196°C or less at normal pressures. The pipe structure comprises: a low-temperature pipe (10) routed along a structural material (4) of a ship (1) at a position separated upward from the structural material (4), and through which cryogenic liquid flows; and a porous heat dissipation layer (20) provided so as to cover the structural material (4) below the low-temperature pipe (10), and for receiving and evaporating drops of liquefied air when the liquefied air is formed on a surface of the low-temperature pipe (10).SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a piping structure for cryogenic liquid that is applied to a ship that stores cryogenic liquid having a boiling point of -196°C or lower at normal pressure, and to the ship. [Background technology]

[0002] The following Patent Document 1 discloses a known piping for flowing the above-mentioned cryogenic liquid. Specifically, the piping in Patent Document 1 is a double-structure piping (double pipe) for flowing liquefied hydrogen, which has a boiling point of -253°C at normal pressure, and has an inner pipe and an outer pipe arranged concentrically. A vacuum layer is formed between the inner pipe and the outer pipe to block heat transfer. The insulating effect of this vacuum layer maintains the temperature of the liquefied hydrogen inside the inner pipe at or below its boiling point. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-20914 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the double-walled pipe for liquefied hydrogen of Patent Document 1, when the degree of vacuum in the heat insulating layer decreases, heat transfer from the inner pipe to the outer pipe becomes easier, and the temperature difference between the outer pipe and the inner pipe decreases. When the temperature of the outer pipe decreases to a temperature close to that of the liquefied hydrogen inside the inner pipe, air may condense on the surface of the outer pipe.

[0005] When liquefied air (liquefied nitrogen or liquefied oxygen) forms on the surface of the outer pipe, this liquefied air drips down the surface of the outer pipe onto the structural materials that make up the ship's hull, located below the double pipe. In this case, the structural materials are significantly cooled by the liquefied air. Since the structural materials are usually made of general structural mild steel such as stainless steel, when they are cooled by the liquefied air, there is a possibility that low-temperature embrittlement, which makes them brittle due to the drop in temperature, will occur.

[0006] The present invention has been made in consideration of the above circumstances, and aims to provide a piping structure for cryogenic liquid, and a ship, which can suppress embrittlement of the structural materials of a ship caused by the effects of dripping of liquefied air formed on the surface of a pipe as the temperature of the pipe through which the cryogenic liquid flows drops. [Means for solving the problem]

[0007] A piping structure for cryogenic liquid according to one aspect of the present invention is a piping structure applied to a ship that stores cryogenic liquid having a boiling point of -196°C or lower at normal pressure, and includes a low-temperature pipe that is routed along a structural material of the ship at a position spaced above the structural material and through which the cryogenic liquid flows, and a porous heat dissipation layer that is provided below the low-temperature pipe so as to cover the structural material and that receives and evaporates droplets of liquefied air when liquefied air forms on the surface of the low-temperature pipe. The low-temperature piping is a multi-layer pipe including an inner pipe through which the cryogenic liquid can flow, an outer pipe concentrically disposed outside the inner pipe, and a vacuum layer formed between the inner pipe and the outer pipe. The heat dissipation layer is provided on the structural material over the entire length of the low-temperature piping.

[0008] A ship according to another aspect of the present invention is a ship that stores cryogenic liquid having a boiling point of -196°C or lower at normal pressure, and includes a hull having a predetermined structural material and the above-mentioned piping structure for cryogenic liquid. Effect of the Invention

[0009] According to the present invention, it is possible to provide a piping structure for cryogenic liquids that can suppress embrittlement of structural materials of a ship caused by dripping of liquefied air formed on the surface of a pipe as the temperature of the pipe through which the cryogenic liquid flows drops, and a ship equipped with the same. [Brief description of the drawings]

[0010] [Figure 1] 1 is a side view showing a schematic structure of a ship to which a cryogenic liquid piping structure according to an embodiment of the present invention is applied. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 2 is a cross-sectional perspective view showing the structure of a hydrogen pipe. [Figure 4] FIG. 2 is a side view showing a piping structure for cryogenic liquid. [Diagram 5] FIG. 5 is a cross-sectional view taken along line VV in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a cryogenic liquid piping structure and a ship for storing and transporting cryogenic liquid according to an embodiment of the present invention will be described with reference to the drawings.

[0012] 1 and 2 are a side view and a cross-sectional view showing a schematic structure of a ship to which a piping structure for a cryogenic liquid according to one embodiment of the present invention is applied. The ship 1 shown in the figures is a liquefied hydrogen carrier that stores and transports liquefied hydrogen L (FIG. 2), and includes a hull 2 ​​and a plurality of tanks 3 mounted on the hull 2. The liquefied hydrogen L stored and transported by the ship 1 is hydrogen in a liquid state that has been cooled to a temperature below its boiling point, which is −253° C. at normal pressure, and corresponds to an example of the cryogenic liquid in the present invention.

[0013] The hull 2 ​​has a plurality of cargo holds 5 that open upward in areas corresponding to each tank 3. A bulkhead 6 is formed between adjacent cargo holds 5 to separate the two cargo holds 5.

[0014] The hull 2 ​​also has a deck 7 around the cargo hold 5. The deck 7 includes a bow deck 7a located in front of the cargo hold 5, a pair of side decks 7b, 7c located on both the left and right sides of the cargo hold 5, and an aft deck 7d located behind the cargo hold 5. The hull 2 ​​is made of steel other than low-temperature steel. For example, each of the decks 7a to 7d is made of general structural mild steel such as SS (Steel Structure) material.

[0015] Each tank 3 is a cylindrical tank that is long in the longitudinal direction of the ship 1, and is housed in a cargo hold 5. Each tank 3 has an inner tank 3a in which liquefied hydrogen L is stored, and an outer tank 3b that is concentrically arranged outside the inner tank 3a. A vacuum layer 3c for thermal insulation is formed between the inner tank 3a and the outer tank 3b. The vacuum layer 3c is an enclosed space that can be communicated with a suction device not shown.

[0016] A tank cover 4 is disposed above each tank 3. Each tank cover 4 constitutes a part of the hull 2, and cooperates with a cargo hold 5 to form an accommodation space S for the tank 3. Like the hull 2, the tank covers 4 are made of a steel material other than low-temperature steel. For example, the tank covers 4 are made of general structural mild steel such as SS material. In other words, the tank covers 4 are made of a steel material that is more susceptible to low-temperature embrittlement, which occurs under extremely low-temperature conditions, than low-temperature steel.

[0017] A hydrogen pipe 10 is disposed on the upper surface of the tank cover 4. The hydrogen pipe 10 is used when at least the liquefied hydrogen L in the tank 3 is loaded from the ship 1, and is the pipe through which the liquefied hydrogen L flows. The hydrogen pipe 10 is arranged at a position spaced above the upper surface of the tank cover 4, so as to extend while appropriately curving along the upper surface of the tank cover 4. The hydrogen pipe 10 corresponds to an example of a low-temperature pipe in the present invention. Furthermore, the tank cover 4 located below the hydrogen pipe 10 corresponds to an example of a structural material for the ship in the present invention.

[0018] 3 is a cross-sectional perspective view showing the structure of hydrogen piping 10. As shown in this figure, hydrogen piping 10 is a multiple pipe including an inner pipe 10a through which liquefied hydrogen L can flow, an outer pipe 10b concentrically arranged outside the inner pipe 10a, and a vacuum layer 10c for heat insulation formed between the inner pipe 10a and the outer pipe 10b. The vacuum layer 10c is an enclosed space that can be communicated with a suction device 12 via a suction port 11 shown in FIGS. 1 and 2.

[0019] In this embodiment, at least the inner pipe 10a of the hydrogen pipe 10 is made of low-temperature steel that is resistant to embrittlement even under extremely low temperature conditions.

[0020] In this embodiment, the outer tube 10b is made of low-temperature steel. The material of the outer tube 10b does not necessarily have to be low-temperature steel, and various metals and resins can be used.

[0021] 4 and 5 are a side view and a cross-sectional view showing a piping structure for cryogenic liquid according to one embodiment of the present invention. In the cross-sectional view of Fig. 5, the liquefied hydrogen L (see Fig. 3) inside the inner pipe 10a is omitted. In the following description, the direction parallel to the axis of the hydrogen pipe 10 is referred to as the tube axis direction X, and the direction perpendicular to the tube axis direction X and the up-down direction (vertical direction) is referred to as the tube axis perpendicular direction Y.

[0022] The piping structure for cryogenic liquid is a piping structure applied to a ship 1 that stores and transports liquefied hydrogen L, which is a cryogenic liquid, and includes a heat dissipation layer 20 and a plurality of support members 30 in addition to the hydrogen piping 10 described above.

[0023] As shown in Fig. 4, the hydrogen pipe 10 has a structure in which a plurality of unit pipes 10A of a predetermined length are connected in the pipe axis direction X. In the hydrogen pipe 10, a suction device 12 for evacuating and maintaining the vacuum of the vacuum layer 10c is connected to each of the plurality of unit pipes 10A via a suction port 11. In other words, the vacuum layer 10c in the hydrogen pipe 10 is evacuated by the suction device 12 not over the entire length of the hydrogen pipe 10, but in sections for each unit pipe 10A. This allows the vacuum layer 10c in the hydrogen pipe 10 to quickly reach a predetermined degree of vacuum, and, if a decrease in the degree of vacuum in the vacuum layer 10c occurs, the phenomenon can be limited to a portion of the hydrogen pipe 10.

[0024] The heat dissipation layer 20 is a porous layer with many holes therein, which is provided below the hydrogen piping 10 so as to cover the upper surface of the tank cover 4. The heat dissipation layer 20 is provided on the upper surface of the tank cover 4 over the entire area where the hydrogen piping 10 is routed. The heat dissipation layer 20 is made of one or more materials selected from asphalt, concrete, and mortar. When liquefied air is formed on the surface of the outer pipe 10b of the hydrogen piping 10 due to a temperature drop in the outer pipe 10b of the hydrogen piping 10, resulting from condensation of nitrogen and oxygen in the air, the heat dissipation layer 20 receives the dripping of the liquefied air and evaporates it.

[0025] The multiple support members 30 are arranged side by side in the tube axis direction X on the upper surface of the tank cover 4. Each support member 30 supports the hydrogen pipe 10 at a position spaced above the tank cover 4 and is in contact with the hydrogen pipe 10. Each support member 30 has a seat 31, a pair of legs 32, and a fastener 33.

[0026] The seat 31 is a plate-shaped member extending in the direction Y perpendicular to the tube axis, and is disposed directly below the hydrogen pipe 10. The hydrogen pipe 10 is fixed to the upper surface of the seat 31 by fasteners 33. In other words, the seat 31 contacts the lower surface of the hydrogen pipe 10 and directly supports the hydrogen pipe 10. Specifically, the seat 31 contacts the lower surface of the outer pipe 10b and supports the outer pipe 10b.

[0027] The fixture 33 is a fastening member formed in an inverted U-shape when viewed from the front. Specifically, the fixture 33 has an upper portion 33a extending in the direction orthogonal to the tube axis Y, and a pair of side portions 33b extending downward from both ends of the upper portion 33a. The pair of side portions 33b are fastened to the seat portion 31 from above at both left and right positions of the hydrogen pipe 10. As a result, the hydrogen pipe 10 is sandwiched between the upper portion 33a and the seat portion 31, and the hydrogen pipe 10 is fixed to the support member 30. Note that a lubricating member or a low-friction member may be disposed between the seat portion 31 of the outer pipe 10b and the outer pipe 10b to allow relative movement between the outer pipe 10b and the seat portion 31 due to thermal contraction or the like.

[0028] The pair of legs 32 are formed to extend downward from both ends (left and right ends) of the seat portion 31 in the pipe axis orthogonal direction Y. The lower ends of the legs 32 are fixed to the upper surface of the tank cover 4 via the heat dissipation layer 20.

[0029] The support member 30 is made of low-temperature steel that is resistant to embrittlement even under extremely low temperature conditions. For example, each of the components constituting the support member 30 (the seat 31, the legs 32, and the fasteners 33) can be made of austenitic stainless steel, which is a type of low-temperature steel. As the austenitic stainless steel, low-carbon stainless steel such as SUS304L or SUS316L is particularly suitable. Of course, it is also possible to use aluminum alloys, which are low-temperature steels other than austenitic stainless steels.

[0030] As described above, in this embodiment, the porous heat dissipation layer 20 is provided so as to cover the tank cover 4 below the hydrogen pipe 10 for flowing liquefied hydrogen L, and the hydrogen pipe 10 is supported via the support member 30 made of low-temperature steel. This has the advantage that embrittlement of the tank cover 4 due to the effect of dripping of liquefied air formed on the surface of the hydrogen pipe 10 as the temperature of the hydrogen pipe 10 decreases can be suppressed.

[0031] The hydrogen piping 10 has a double structure including an inner pipe 10a and an outer pipe 10b. A vacuum layer 10c is formed between the two pipes 10a and 10b. As long as the degree of vacuum in the vacuum layer 10c is sufficient, the temperature of the outer pipe 10b is maintained at a sufficiently high value relative to the temperature of the inner pipe 10a, even if liquefied hydrogen L flows inside the inner pipe 10a. However, the degree of vacuum in the vacuum layer 10c may decrease due to long-term operation of the ship 1, etc., and when such a decrease in the degree of vacuum occurs, heat transfer between the inner pipe 10a and the outer pipe 10b is promoted, and the temperature difference between the outer pipe 10b and the inner pipe 10a is reduced. In an extreme example, the temperature of the outer pipe 10b may decrease to a temperature close to the temperature of the liquefied hydrogen inside the inner pipe 10a (-253°C or lower).

[0032] As described above, the hydrogen pipe 10 has a structure in which a plurality of unit tubes 10A are connected together, and the degree of vacuum in the vacuum layer 10c is maintained separately for each unit tube 10A. Therefore, the degree of vacuum in the vacuum layer 10c does not decrease uniformly over the entire length of the hydrogen pipe 10, and the degree of decrease in the degree of vacuum may differ for each unit tube 10A. Therefore, even if the temperature of the outer tube 10b decreases to a temperature close to that of the liquefied hydrogen L, such a phenomenon usually occurs only in a part of the hydrogen pipe 10. For this reason, hereinafter, the part of the hydrogen pipe 10 whose surface temperature has decreased to a temperature close to that of the liquefied hydrogen L will be specifically referred to as the temperature-reduced part.

[0033] When a temperature drop occurs in the hydrogen piping 10, the crew of the ship 1 repairs the unit tube 10A corresponding to the temperature drop or replaces it with a new unit tube 10A. However, before such work is completed, nitrogen and oxygen in the air may condense on the surface of the outer tube 10b in the temperature drop portion of the hydrogen piping 10, forming liquefied air. When such liquefied air drips down the surface of the outer tube 10b onto the tank cover 4 located below the temperature drop portion, the tank cover 4 is significantly cooled by the liquefied air. Since the tank cover 4 is usually made of general structural mild steel such as SS material, when it is cooled by the liquefied air, low-temperature embrittlement, which makes the tank cover brittle due to the temperature drop, may occur.

[0034] In view of this problem, in this embodiment, a porous heat dissipation layer 20 is provided below the hydrogen piping 10 so as to cover the tank cover 4. This allows the liquefied air dripping from the hydrogen piping 10 to be accurately received by the heat dissipation layer 20, and the received liquefied air can be quickly evaporated by the temperature of the heat dissipation layer 20. The heat dissipation layer 20 is a porous layer with a large surface area, so it is easy to evaporate the received liquefied air. This makes it less likely that the liquefied air will reach the tank cover 4 and cause the tank cover 4 to be significantly cooled, thereby appropriately protecting the tank cover 4 from low-temperature embrittlement.

[0035] Furthermore, the heat dissipation layer 20 is made of one or more materials selected from asphalt, concrete, and mortar, which are inherently porous. For example, the heat dissipation layer 20 may be formed of a single layer of asphalt, or may be formed of a laminate of asphalt and concrete. Asphalt, concrete, and mortar have the property of being less susceptible to low-temperature embrittlement. Therefore, it is possible to suppress low-temperature embrittlement of the heat dissipation layer 20 that may occur when liquefied air is dripped onto the heat dissipation layer 20 from the hydrogen pipe 10. Furthermore, by using these materials, the porous heat dissipation layer 20 can be easily and inexpensively formed on the upper surface of the tank cover 4.

[0036] Furthermore, the heat dissipation layer 20 is provided over the entire area where the hydrogen piping 10 is routed on the upper surface of the tank cover 4. As a result, even if the hydrogen piping 10 is routed above the tank cover 4 so as to extend while appropriately curving, resulting in a complex piping layout, and even if a significant drop in temperature occurs at multiple points on the hydrogen piping 10, the drops of liquefied air generated at each temperature drop point can be accurately received by the heat dissipation layer 20.

[0037] In addition, in the temperature drop portion of the hydrogen pipe 10, the temperature of the outer pipe 10b drops to a temperature close to that of the liquefied hydrogen L. If the support member 30 is provided in such a temperature drop portion, the support member 30 (particularly the seat portion 31 and the fastener 33 in contact with the hydrogen pipe 10) will be significantly cooled by heat conduction from the temperature drop portion. If the material of the support member 30 were general structural mild steel similar to that of the tank cover 4, the support member 30 would become brittle due to low-temperature embrittlement, and it may become impossible to properly support the hydrogen pipe 10. In view of this problem, in this embodiment, the material of the support member 30 is low-temperature steel that is not easily embrittled even under extremely low temperature conditions. Therefore, even if the support member 30 is significantly cooled, the low-temperature embrittlement of the support member 30 can be sufficiently suppressed, and the support strength of the support member 30 for the hydrogen pipe 10 can be well maintained.

[0038] Although the cryogenic liquid piping structure and the ship according to the embodiment of the present invention have been described above, the present invention is not limited thereto, and for example, the following modified embodiments can be adopted.

[0039] In the above embodiment, a structure in which the heat dissipation layer 20 is provided over the entire area in which the hydrogen piping 10 is routed on the upper surface of the tank cover 4 has been exemplified, but the present invention is not limited to such a structure. For example, the heat dissipation layer 20 may be provided on the upper surface of the tank cover 4 so as to extend over the entire length of the hydrogen piping 10 along the axial direction X of the hydrogen piping 10. Furthermore, if it is known in advance which locations in the hydrogen piping 10 are particularly prone to a decrease in the degree of vacuum of the vacuum layer 10c, the heat dissipation layer 20 may be provided exclusively below such locations.

[0040] In the above embodiment, a structure in which the hydrogen piping 10 is disposed above the tank cover 4 of the ship 1 has been exemplified, but the hydrogen piping 10 may be disposed not only above the tank cover 4 but also above the deck 7, or may be disposed inside a room such as a cargo equipment room. Even when the hydrogen piping is disposed in a location other than above the tank cover 4 in this manner, it is possible to provide a heat dissipation layer 20 in a location other than above the tank cover 4 and apply a support structure using support members 30 similar to that in the above embodiment.

[0041] In the above embodiment, a double pipe having an inner pipe 10a and an outer pipe 10b with a vacuum layer 10c formed between them is used as the hydrogen pipe 10, but it is also possible to use a non-double-walled pipe without a vacuum layer as the low-temperature pipe. For example, a pipe having a main pipe made of low-temperature steel and a heat insulating layer such as a urethane layer formed on its outer surface can be used as the low-temperature pipe.

[0042] In the above embodiment, an example in which the piping structure of the present invention is applied to a ship 1 that stores and transports liquefied hydrogen L having a boiling point of -253°C at normal pressure has been described, but the present invention is not limited to this. The ship to which the piping structure of the present invention can be applied may be one that stores a cryogenic liquid having a boiling point of -196°C or less at normal pressure, and to that extent, the piping structure of the present invention can be applied to various ships. For example, the piping structure of the present invention can be similarly applied to a ship that stores liquefied helium having a boiling point of -269°C at normal pressure or liquefied nitrogen having a boiling point of -196°C at normal pressure.

[0043] The inventions included in the above-described embodiment and modified examples can be summarized as follows.

[0044] A piping structure for cryogenic liquid according to one aspect of the present invention is a piping structure applied to a ship that stores cryogenic liquid having a boiling point of -196°C or lower at normal pressure, and includes a low-temperature pipe that is routed along a structural material of the ship at a position spaced above the structural material and through which the cryogenic liquid flows, and a porous heat dissipation layer that is provided below the low-temperature pipe so as to cover the structural material and that receives and evaporates droplets of liquefied air when liquefied air forms on the surface of the low-temperature pipe.

[0045] In a low-temperature pipe through which a cryogenic liquid having a boiling point of -196°C or less at normal pressure flows, the surface temperature of at least a part of the pipe may drop to a temperature close to that of the cryogenic liquid. In a temperature-reduced part of the low-temperature pipe where a significant temperature drop occurs, nitrogen and oxygen in the air may condense on the surface, forming liquefied air. When such liquefied air drips down the surface of the low-temperature pipe onto a structural material of a ship located below the low-temperature pipe, the structural material is significantly cooled by the liquefied air. Since the structural material of a ship is usually made of general structural mild steel such as SS material, when it is cooled by liquefied air, low-temperature embrittlement, which becomes brittle due to the temperature drop, may occur. In view of this problem, in the present invention, a porous heat dissipation layer is provided below the low-temperature pipe so as to cover the structural material. Therefore, the liquefied air dripped from the low-temperature pipe can be accurately received by the heat dissipation layer and evaporated. This makes it possible to prevent the liquefied air from reaching the structural material of the ship with a sufficiently high probability, and to appropriately protect the structural material from low-temperature embrittlement.

[0046] In the above-mentioned piping structure for cryogenic liquid, the heat dissipation layer may be made of one or more materials selected from asphalt, concrete, and mortar.

[0047] Asphalt, concrete, and mortar have the property of being less susceptible to low-temperature embrittlement. Therefore, it is possible to suppress low-temperature embrittlement of the heat dissipation layer that may occur when liquefied air is dripped onto the heat dissipation layer from a low-temperature pipe. Furthermore, by using these materials, it is possible to easily and inexpensively form a porous heat dissipation layer on the structural material of a ship.

[0048] In the above-described piping structure for cryogenic liquid, the heat dissipation layer may be provided over the entire area of ​​the structural material in which the cryogenic piping is routed.

[0049] In this aspect, even if the low-temperature piping is arranged above the structural material so that it extends while appropriately curving, resulting in a complex piping layout, and even if a significant drop in temperature occurs at multiple points in the low-temperature piping, the drops of liquefied air generated at each temperature drop section can be accurately received by the heat dissipation layer.

[0050] The above-mentioned piping structure for cryogenic liquid may further include a support member that supports the low-temperature piping at a position spaced above the structural material and in contact with the low-temperature piping, and the support member may be made of low-temperature steel that is less susceptible to low-temperature embrittlement than the structural material.

[0051] When a significant temperature drop occurs in the low-temperature piping, the support member supporting the low-temperature piping may be significantly cooled by heat conduction from the low-temperature piping. In this case, if the support member is made of the same material as the structural material of the ship, the support member may become brittle due to low-temperature embrittlement and may not be able to properly support the low-temperature piping. In view of this problem, the support member is made of low-temperature steel, which is less susceptible to low-temperature embrittlement than the structural material. Therefore, even if the support member is significantly cooled, the low-temperature embrittlement of the support member can be sufficiently suppressed, and the support strength of the support member for the low-temperature piping can be well maintained.

[0052] A ship according to another aspect of the present invention is a ship that stores cryogenic liquid having a boiling point of -196°C or lower at normal pressure, and includes a hull having a predetermined structural material and the above-mentioned piping structure for cryogenic liquid.

[0053] According to this ship, the structural materials constituting the hull can be protected from low-temperature embrittlement. [Explanation of symbols]

[0054] 1 ship 2. Hull 3. Tank 4 Tank cover (structural material) 10 Hydrogen piping (low temperature piping) 20 Heat dissipation layer 30 Support member L Liquefied hydrogen (cryogenic liquid)

Claims

1. A piping structure applied to a ship that stores a cryogenic liquid having a boiling point of −196° C. or lower at normal pressure, a low-temperature pipe arranged along a structural member of the ship at a position spaced above the structural member, through which the cryogenic liquid flows; a porous heat dissipation layer that is provided below the low-temperature piping so as to cover the structural material, and that receives and evaporates drops of liquefied air when liquefied air is formed on the surface of the low-temperature piping; the low-temperature piping is a multi-layer pipe including an inner pipe through which the cryogenic liquid can flow, an outer pipe concentrically disposed outside the inner pipe, and a vacuum layer formed between the inner pipe and the outer pipe, A piping structure for cryogenic liquid, wherein the heat dissipation layer is provided on the structural material over the entire length of the low-temperature piping.

2. 2. The piping structure for cryogenic liquid according to claim 1, wherein the heat dissipation layer is made of one or more materials selected from the group consisting of asphalt, concrete, and mortar.

3. 3. The piping structure for cryogenic liquid according to claim 1, wherein the heat dissipation layer is provided over the entire area of ​​the structural material in which the low-temperature piping is routed.

4. a support member that supports the low-temperature pipe at a position above and spaced apart from the structural material and that is in contact with the low-temperature pipe, 4. The piping structure for cryogenic liquid according to claim 1, wherein the support member is made of low-temperature steel which is less susceptible to low-temperature embrittlement than the structural material.

5. A ship that stores cryogenic liquid having a boiling point of -196°C or lower at normal pressure, A hull having a predetermined structural material; A ship comprising the cryogenic liquid piping structure according to any one of claims 1 to 4.

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