Piping structure for cryogenic liquid and ship equipped with same

Abstract

To suppress embrittlement of other members by lowering of temperature in a piping in which ultralow temperature liquid is circulating.SOLUTION: A piping structure for ultralow temperature liquid is applied to a vessel storing ultralow temperature liquid with a boiling point at -196°C or less under normal pressure. The piping structure includes low temperature piping (10) in which the ultralow temperature liquid is circulated and a support member 30 supporting the low temperature piping (10) in a position separated above structure material (4) of the vessel as well as coming into contact with the low temperature piping (10). The support member 30 is composed of steel for low temperature use with hardy any occurrence of low temperature embrittlement.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a piping structure applied to a ship that stores cryogenic liquid having a boiling point of -196°C or lower at normal pressure. [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 becomes smaller. 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] If the temperature of the outer tube drops to a temperature at which liquefied air is formed, other components in contact with the part where this temperature drop occurs (hereinafter referred to as the temperature drop part) may suffer from low-temperature embrittlement, in which the material becomes brittle due to the temperature drop. In addition, if the liquefied air generated in the temperature drop part reaches other components along the surface of the outer tube, the other components may be significantly cooled by the liquefied air, causing low-temperature embrittlement.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a piping structure for cryogenic liquid that can suppress embrittlement of other components due to a drop in temperature in the piping through which the cryogenic liquid flows, and a ship equipped with the same. [Means for solving the problem]

[0007] In order to solve the above problems, 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, the piping structure comprising: a cryogenic pipe through which the cryogenic liquid flows; and a support member that supports the cryogenic pipe at a position above and away from a structural material of the ship and that is in contact with the cryogenic pipe. a dish-shaped drip tray disposed below the low-temperature piping so as to receive drips of liquefied air when liquefied air is formed on the surface of the low-temperature piping; Equipped with the support member includes a seat portion that contacts a lower surface of the low-temperature pipe to support the low-temperature pipe, a fastener that fixes the low-temperature pipe to the seat portion, at least a pair of legs that extend downward from the seat portion, and an auxiliary support member that connects the pair of legs to each other and supports the drip tray, The support member is made of low-temperature steel which is resistant to low-temperature embrittlement.

[0008] A ship according to another aspect of the present invention is a ship for storing cryogenic liquid having a boiling point of -196°C or lower at normal pressure, comprising a tank for storing the cryogenic liquid, a tank cover covering the tank, a deck, and the above-mentioned piping structure for cryogenic liquid, wherein the structural material is the tank cover or the deck. Effect of the Invention

[0009] According to the present invention, it is possible to provide a piping structure for cryogenic liquid and a ship capable of suppressing embrittlement of other members due to a drop in temperature of the piping through which the cryogenic liquid flows. [Brief description of the drawings]

[0010] [Figure 1] 1 is a side view showing a schematic structure of a ship to which a piping structure according to one 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. 4 is a side view showing a structure for supporting the hydrogen piping on the tank cover. [Diagram 5] FIG. 5 is a cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. [Figure 7] FIG. 13 is a diagram for explaining a modified example of the above embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] 1 and 2 are a side view and a cross-sectional view showing a schematic structure of a ship to which a piping structure 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 two tanks 3 mounted on the hull 2. The number of tanks 3 may be three or more, or may be one. The liquefied hydrogen L transported by the ship 1 of this embodiment is hydrogen in a liquid phase state that has been cooled to a temperature below its boiling point (−253° C. at normal pressure), and corresponds to an example of a cryogenic liquid in the present invention.

[0012] The hull 2 ​​has two cargo holds 5 that open upward in areas corresponding to the tanks 3. A bulkhead 6 is formed between adjacent cargo holds 5 to separate the two cargo holds 5. The number of cargo holds 5 may be three or more, or may be one.

[0013] 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.

[0014] 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 suction means not shown.

[0015] A tank cover 4 is disposed above each tank 3. Each tank cover 4 cooperates with a cargo hold 5 to form an accommodation space S for the tank 3.

[0016] The hull 2 ​​is made of steel. For example, the decks 7a to 7d and the tank cover 4 are each made of general structural mild steel such as stainless steel.

[0017] Hydrogen piping 10 is disposed on the upper surface of the tank cover 4. The hydrogen piping 10 is used when loading and unloading at least the liquefied hydrogen L in the tank 3 from the ship 1, and is arranged so as to extend while appropriately curving along the upper surface of the tank cover 4. The hydrogen piping 10 corresponds to an example of low-temperature piping in the present invention. Furthermore, the tank cover 4 located below the hydrogen piping 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 the hydrogen pipe 10. As shown in this figure, the hydrogen pipe 10 has an inner pipe 10a through which liquefied hydrogen L can flow, and an outer pipe 10b arranged concentrically around the inner pipe 10a. A vacuum layer 10c for thermal insulation is 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 means not shown.

[0019] 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. The material of the outer pipe 10b does not necessarily have to be low-temperature steel, but the outer pipe 10b in this embodiment is made of the same low-temperature steel as the inner pipe 10a.

[0020] 4 to 6 are side and cross-sectional views showing a structure for supporting the hydrogen pipes 10 on the tank cover 4. As shown in these figures, the hydrogen pipes 10 are disposed at a position a predetermined distance above the tank cover 4, and are supported by the tank cover 4 via a base rack 20 and a plurality of support members 30. Note that the cross-sectional views of Figs. 5 and 6 omit illustration of the liquefied hydrogen L inside the inner pipe 10a. In the following description, the direction parallel to the axis of the hydrogen pipes 10 is referred to as the pipe axis direction X, and the direction perpendicular to the pipe axis direction X and the up-down direction (vertical direction) is referred to as the pipe axis orthogonal direction Y.

[0021] The base rack 20 includes a plurality of pillar members 21 and an upper frame 22 supported by each pillar member 21. Each of the pillar members 21 is a columnar member extending upward from the tank cover 4, and is fixed to the upper surface of the tank cover 4 at a plurality of locations spaced apart (distributed) in the tube axis direction X and the tube axis orthogonal direction Y. The upper frame 22 is composed of a plurality of frame members fixed to the upper end of each pillar member 21 in a state of being combined in a lattice shape in a plan view. Specifically, the upper frame 22 has a plurality of vertical frame members 22a extending in the tube axis direction X and a plurality of horizontal frame members 22b connecting each vertical frame member 22a in the tube axis orthogonal direction Y. Each vertical frame member 22a is arranged so as to bridge the upper ends of the pillar members 21 aligned in the tube axis direction X, and each horizontal frame member 22b is arranged so as to bridge the upper ends of the pillar members 21 aligned in the tube axis orthogonal direction Y.

[0022] The multiple support members 30 are arranged side by side in the tube axis direction X on the upper side of the base rack 20. Each support member 30 has a seat portion 31, a pair of legs 32, and a fastener 33.

[0023] The seat 31 is a plate-like 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 a fastener 33. In other words, the seat 31 contacts the lower surface of the outer pipe 10b of the hydrogen pipe 10 and directly supports the hydrogen pipe 10. Note that a lubricating member or low-friction member may be disposed between the seat 31 of the outer pipe 10b and the outer pipe 10b to allow relative movement between the outer pipe 10b and the seat 31 due to thermal contraction or the like.

[0024] The fixture 33 is a fastening member formed in an inverted U-shape when viewed from the front, a so-called U-bolt. 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.

[0025] The pair of legs 32 are formed to extend downward from both left and right ends of the seat 31, i.e., both ends of the seat 31 in the direction perpendicular to the pipe axis Y. The lower ends of the legs 32 are fixed to the upper frame 22 of the base rack 20 (the vertical frame member 22a in the illustrated example) by welding or the like.

[0026] A drip tray 40 extending in the tube axis direction X is disposed between the hydrogen pipe 10 and the base rack 20. The drip tray 40 is a relatively shallow square dish-shaped member, and has a flat bottom 41 long in the tube axis direction X, and a pair of rising parts 42 rising upward from both ends of the bottom 41 in the tube axis direction Y. The width dimension (dimension in the tube axis direction Y) of the drip tray 40 is set to be equal to or larger than the diameter of the hydrogen pipe 10, and smaller than the distance between a pair of legs 32 of the support member 30 (the distance from the inner surface of one leg 32 to the inner surface of the other leg 32). The length dimension (dimension in the tube axis direction X) of the drip tray 40 is set to be approximately the same as the entire length of the hydrogen pipe 10. That is, the drip tray 40 is disposed so as to extend over approximately the entire length of the hydrogen pipe 10. Such a long drip tray 40 can be constructed, for example, by joining together a plurality of trays divided in the tube axis direction X.

[0027] The drip tray 40 is supported by the base rack 20 via a plurality of tray support members 50 (see FIGS. 4 and 6) arranged in the tube axis direction X. The tray support members 50 each have a seat portion 51 and a pair of legs 52.

[0028] The seat 51 is a plate-shaped member extending in the tube axis perpendicular direction Y, and is disposed directly below the drip tray 40. The drip tray 40 is fixed to the upper surface of the seat 51 by welding or the like. In other words, the seat 51 contacts the lower surface of the drip tray 40 and directly supports the drip tray 40. In this supported state, the drip tray 40 is disposed so as to extend in the tube axis direction X through between a pair of legs 32 of the support member 30 for the hydrogen pipe 10. The seat 51 is attached at a height approximately halfway between the lower surface of the hydrogen pipe 10 and the upper surface of the base rack 20 so that the drip tray 40 is disposed at a distance below the hydrogen pipe 10.

[0029] The pair of legs 52 are formed to extend downward from both left and right ends of the seat 51, i.e., both ends of the seat 51 in the direction perpendicular to the pipe axis Y. The lower ends of each leg 52 are fixed to the upper frame 22 of the base rack 20. Specifically, the lower ends of each leg 52 are fixed to the vertical frame members 22a of the upper frame 22 by welding or the like.

[0030] 4 and 5, the support member 30 for the hydrogen pipe 10 further includes an auxiliary support member 35 for supporting the drip tray 40. The auxiliary support member 35 is a member that extends in the direction perpendicular to the tube axis Y at a height position directly below the drip tray 40, and is attached so as to connect a pair of legs 32 of the support member 30 to each other in the direction perpendicular to the tube axis Y. It can be said that the support member 30 including such an auxiliary support member 35 has both the function of supporting the hydrogen pipe 10 and the function of supporting the drip tray 40.

[0031] The support member 30, the drip tray 40, and the tray support member 50 are made of low-temperature steel that is not easily embrittled even under extremely low temperature conditions. For example, the seat 31, the legs 32, the fasteners 33, and the auxiliary support 35 constituting the support member 30, the seat 51 and the legs 52 constituting the tray support member 50, and the drip tray 40 can each be made of austenitic stainless steel, which is a type of low-temperature steel. As the austenitic stainless steel, low-carbon stainless steels such as SUS304L and SUS316L are particularly suitable. Of course, it is also possible to use low-temperature steels other than austenitic stainless steels, such as aluminum alloys.

[0032] On the other hand, the base rack 20 (its column members 21 and upper frame 22) is made of a steel material other than low-temperature steel, for example, a general structural mild steel similar to the material of the tank cover 4. In other words, the base rack 20 and the tank cover 4 are made of a steel material that is more susceptible to low-temperature embrittlement, which is embrittlement under extremely low-temperature conditions, than low-temperature steel.

[0033] As described above, in this embodiment, the hydrogen piping 10 for flowing liquefied hydrogen L is supported on the tank cover 4 via a support member 30 made of low-temperature steel, and a drip tray 40 is arranged below the hydrogen piping 10, which has the advantage of suppressing embrittlement of other components due to a drop in temperature of the hydrogen piping 10.

[0034] The hydrogen piping 10 has a double structure including an inner pipe 10a and an outer pipe 10b, and 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. Here, since the hydrogen pipe 10 generally has a structure in which a number of unit tubes, each having a finite length in the tube axis direction X, are joined together, it is considered that the degree of vacuum does not decrease uniformly over the entire length of the hydrogen pipe 10, but the degree of decrease in the degree of vacuum differs depending on the position in the tube axis direction X (each unit tube). For this reason, 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 (the temperature of the outer tube 10b) has decreased to a temperature close to that of the liquefied hydrogen L will be specifically referred to as the temperature-reduced part.

[0035] 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 were provided in such a temperature drop portion, the support member 30 (particularly the seat 31 and the fixture 33 in contact with the hydrogen pipe 10) would be significantly cooled by heat transfer from the temperature drop portion. In addition, in the temperature drop portion of the hydrogen pipe 10, nitrogen or oxygen in the air may condense on the surface of the outer pipe 10b to form liquefied air (liquefied nitrogen or liquefied oxygen, etc.). If such liquefied air reaches the support member 30 along the surface of the outer pipe 10b, the support member 30 would also be significantly cooled. In these cases, if the material of the support member 30 were the same general structural mild steel as the tank cover 4, the support member 30 would become brittle due to low-temperature embrittlement, and it may not be possible to properly support the hydrogen pipe 10. In contrast, in the above 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 cooled significantly as described above, low-temperature embrittlement of the support member 30 can be sufficiently suppressed, and the support strength of the support member 30 for the hydrogen piping 10 can be well maintained.

[0036] Furthermore, in the above embodiment, the drip tray 40 is disposed below the hydrogen piping 10, so that even if liquefied air formed in the temperature-reducing portion of the hydrogen piping 10 drips from the hydrogen piping 10 as described above, the drip tray 40 can receive this dripped liquefied air, and the received liquefied air can be quickly evaporated by the temperature of the drip tray 40. 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 making it possible to appropriately protect the tank cover 4 from low-temperature embrittlement.

[0037] Furthermore, in the above embodiment, the drip tray 40 is formed to extend along the tube axis direction X of the hydrogen piping 10. Therefore, even if a significant drop in temperature occurs at multiple locations of the hydrogen piping 10 that are separated in the tube axis direction X, the drip tray 40 can accurately receive the liquefied air generated at each temperature drop portion.

[0038] Furthermore, in the above embodiment, the drip tray 40 is disposed so as to pass between the pair of legs 32 of the support member 30 and extend in the tube axis direction X, so that the drip tray 40 can be disposed at an appropriate position below the hydrogen pipe 10 while avoiding interference between the drip tray 40 and the support member 30. This allows both the support member 30 to properly support the hydrogen pipe 10 and the drip tray 40 to properly receive the liquefied air.

[0039] In addition, in the above embodiment, the drip tray 40 is supported by the tray support member 50, and the drip tray 40 and the tray support member 50 are each made of low-temperature steel, so that low-temperature embrittlement of the drip tray 40 and the tray support member 50 that may occur when liquefied air is dripped from the hydrogen piping 10 onto the drip tray 40 can be suppressed.

[0040] Furthermore, in the above embodiment, the base rack 20 made of the same material as the tank cover 4 (general structural mild steel) is constructed on the tank cover 4, and the support members 30 and the tray support members 50 are attached to the upper side of the upper frame 22 of this base rack 20, so that it is possible to reduce the proportion of low-temperature steel among the various members used to support the piping, while sufficiently increasing the vertical distance between the hydrogen piping 10 and the tank cover 4. This makes it possible to further reduce the possibility that liquefied air dripping from the hydrogen piping 10 will reach the tank cover 4, with a rational structure that does not entail a significant increase in cost.

[0041] In the above embodiment, the tray support member 50 supporting the drip tray 40 is attached to the upper frame 22 of the base rack 20. Alternatively, a structure as shown in FIG. 7 in which the drip tray 40 is supported by the hydrogen pipe 10 itself may be adopted. That is, in the modified example of FIG. 7, the drip tray 40 is supported by an inverted U-shaped support member 70 attached to the hydrogen pipe 10. The support member 70 includes a fixing portion 71 fixed to the upper surface of the hydrogen pipe 10, a pair of extension portions 72 extending downward from both the left and right ends of the fixing portion 71, and a pair of support portions 73 extending inward from the lower ends of the extension portions 72. The drip tray 40 is fixed to the support member 70 by means of welding or the like while being placed on the upper surfaces of the support portions 73.

[0042] In the above embodiment, the drip tray 40 is disposed so as to extend over substantially the entire length of the hydrogen piping 10. However, if certain locations in the hydrogen piping 10 that are particularly susceptible to temperature drops (vacuum level drops) are known in advance, the drip tray may be provided only in such locations.

[0043] In the above embodiment, a square dish-shaped drip tray having a bottom 41 and a pair of raised portions 42 is used as the drip tray 40, but the drip tray of the present invention may have any shape capable of receiving drips of liquefied air when the liquefied air is formed on the surface of the hydrogen pipe 10, and drip trays of various shapes may be used as long as such shapes are capable of receiving drips of liquefied air when the liquefied air is formed on the surface of the hydrogen pipe 10. For example, a simple flat member may be used as the drip tray.

[0044] In the above embodiment, low-temperature steel is used as the material for the drip tray 40. However, when insulating material, gravel, etc. are used in combination with the drip tray, that is, when insulating material, gravel, etc. are laid on the upper surface of the drip tray, the material for the drip tray can also be a steel material other than low-temperature steel.

[0045] 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 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. In this way, a support structure similar to that of the above embodiment can be applied to hydrogen piping disposed in a location other than above the tank cover 4.

[0046] In the above embodiment, a double-walled 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 a non-double-walled pipe without a vacuum layer can also be used 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.

[0047] In the above embodiment, an example was described in which the piping structure of the present invention was applied to a ship 1 that stores and transports liquefied hydrogen L, which has a boiling point of -253°C at normal pressure, but the ship to which the piping structure of the present invention can be applied may be one that stores a cryogenic liquid whose boiling point is -196°C or lower 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 also be applied to a ship that stores liquefied helium, which has a boiling point of -269°C at normal pressure, or liquefied nitrogen, which has a boiling point of -196°C at normal pressure.

[0048] 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 comprises a low-temperature pipe through which the cryogenic liquid flows, and a support member that supports the low-temperature pipe at a position above and away from the structural material of the ship and in contact with the low-temperature pipe, the support member being made of low-temperature steel that is resistant to low-temperature embrittlement.

[0049] 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. If a support member is provided in a part where such a large temperature drop occurs (hereinafter referred to as a temperature drop part), the support member may be significantly cooled by heat transfer from the temperature drop part. In addition, in the temperature drop part, nitrogen or oxygen in the air may condense on the surface of the part to form liquefied air (liquefied nitrogen or liquefied oxygen, etc.). If such liquefied air reaches the support member along the surface of the pipe, the support member may also be significantly cooled. In these cases, if the material of the support member is the same as that of 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 pipe. In contrast, in the present invention, the material of the support member is low-temperature steel that is unlikely to cause low-temperature embrittlement, so that even if the support member is significantly cooled as described above, the low-temperature embrittlement of the support member can be sufficiently suppressed, and the support strength of the low-temperature pipe by the support member can be well maintained.

[0050] Furthermore, by providing the support member between the structural material of the ship and the low-temperature piping, even if liquefied air is formed in the temperature-reducing portion of the low-temperature piping as described above, the possibility of the liquefied air directly reaching the structural material is reduced. For example, liquefied air dripping from the low-temperature piping may adhere to the support member and evaporate, or may adhere to some piping component other than the support member and evaporate. This reduces the possibility of the liquefied air reaching the structural material, and thus prevents the structural material from being significantly cooled and embrittled.

[0051] Preferably, the piping structure further comprises a drip tray disposed below the cryogenic piping so as to receive drips of liquefied air when liquefied air forms on a surface of the cryogenic piping.

[0052] According to this configuration, the liquefied air dripping from the low-temperature piping can be accurately received by the drip tray and evaporated, which can prevent the liquefied air from reaching the structural material with a sufficiently high probability, thereby appropriately protecting the structural material from low-temperature embrittlement.

[0053] In the above configuration, more preferably, the drip tray has a shape extending along the axial direction of the low-temperature pipe.

[0054] With this configuration, even if a significant drop in temperature occurs at multiple locations in the low-temperature piping that are separated in the axial direction of the tube, the liquefied air generated at each temperature drop portion can be accurately received by the drip tray.

[0055] In the above configuration, more preferably, the support member includes a seat portion that contacts the underside of the low-temperature piping to support the low-temperature piping, a fastener that fixes the low-temperature piping to the seat portion, and at least a pair of legs extending downward from the seat portion, and the drip tray is arranged to extend in the tube axis direction between the pair of legs.

[0056] According to this configuration, the drip tray can be disposed in an appropriate position below the low-temperature pipe while avoiding interference between the drip tray and the support member, thereby achieving both the appropriate support of the low-temperature pipe by the support member and the proper reception of liquefied air by the drip tray.

[0057] Preferably, the piping structure further includes a tray support member that supports the drip tray below the low-temperature piping, and the drip tray and the tray support member are made of low-temperature steel that is resistant to low-temperature embrittlement.

[0058] According to this configuration, it is possible to suppress low-temperature embrittlement of the drip tray and the tray support member that can occur when liquefied air drips from the low-temperature piping onto the drip tray.

[0059] In the above configuration, more preferably, the piping structure further includes a base rack fixed to an upper surface of the structural material and made of a steel material that is more susceptible to low-temperature embrittlement than the low-temperature steel, the base rack having a plurality of column members extending upward from the structural material and an upper frame fixed to the upper ends of each column member, and the support member and the tray support member being attached to the upper side of the upper frame.

[0060] In this way, when the support members and the tray support members are disposed above the base rack constructed on the structural members of the ship, the vertical distance between the low-temperature piping and the structural members of the ship can be sufficiently increased, while the proportion of low-temperature steel in the various members for supporting the piping can be reduced. This makes it possible to further reduce the possibility that liquefied air dripping from the low-temperature piping will reach the structural members, with a rational structure that does not significantly increase costs.

[0061] The support member may include a fixing portion that is fixed to the low-temperature piping, and a support portion that supports the drip tray.

[0062] This configuration also allows for proper mounting of a drip tray below the cryogenic piping.

[0063] A ship according to another aspect of the present invention is a ship for storing cryogenic liquid having a boiling point of -196°C or lower at normal pressure, comprising a tank for storing the cryogenic liquid, a tank cover covering the tank, a deck, and the above-mentioned piping structure for cryogenic liquid, wherein the structural material is the tank cover or the deck.

[0064] According to the present invention, it is possible to properly support low-temperature piping above a tank cover or deck while protecting the tank cover or deck from low-temperature embrittlement. [Explanation of symbols]

[0065] 1: Ship 3: Tank 4: Tank cover 7:Deck 10: Hydrogen piping (low temperature piping) 20: Base rack 21:Column member 22: Upper frame 30: Support member 31: Seat part 32: Legs 33: Fixture 40: Drip tray 50: Tray support member 70: Support member 71:Fixed part 73: Support part L: Liquefied hydrogen (cryogenic liquid) X: Tube axis direction

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 through which the cryogenic liquid flows; a support member that supports the low-temperature piping at a position spaced above a structural member of the ship and that is in contact with the low-temperature piping; a dish-shaped drip tray disposed below the low-temperature piping so as to receive drips of liquefied air when liquefied air is formed on the surface of the low-temperature piping; the support member includes a seat portion that contacts a lower surface of the low-temperature pipe to support the low-temperature pipe, a fastener that fixes the low-temperature pipe to the seat portion, at least a pair of legs that extend downward from the seat portion, and an auxiliary support member that connects the pair of legs to each other and supports the drip tray, The support member is made of low-temperature steel that is resistant to low-temperature embrittlement.

2. 2. The piping structure for cryogenic liquid according to claim 1, The drip tray has a shape extending along the axial direction of the low-temperature pipe, the piping structure for cryogenic liquid.

3. 3. The piping structure for cryogenic liquid according to claim 2, The drip tray is disposed so as to pass between the pair of legs and extend in the tube axis direction.

4. The piping structure for cryogenic liquid according to any one of claims 1 to 3, a tray support member for supporting the drip tray below the low-temperature piping; The drip tray and the tray support member are made of low-temperature steel that is resistant to low-temperature embrittlement.

5. 5. The piping structure for cryogenic liquid according to claim 4, The base rack is fixed to an upper surface of the structural material and is made of a steel material that is more susceptible to low-temperature embrittlement than the low-temperature steel. The base rack has a plurality of pillar members extending upward from the structural member and an upper frame fixed to the upper ends of the pillar members, A piping structure for cryogenic liquid, wherein the support member and the tray support member are attached to the upper side of the upper frame.

6. A ship that stores cryogenic liquid having a boiling point of -196°C or lower at normal pressure, A tank for storing the cryogenic liquid; A tank cover that covers the tank; The deck and The piping structure for cryogenic liquid according to any one of claims 1 to 5, The ship, wherein the structural material is the tank cover or the deck.

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