Insulation material for liquid hydrogen tank, liquid hydrogen tank and insulation material installation method

Abstract

To provide an insulation material for a liquid hydrogen tank restricting occurrence of static electricity of the liquid hydrogen pooled in the liquid hydrogen tank and restricting risk of explosion due to the static electricity, the liquid hydrogen tank and an insulation material construction method.SOLUTION: An insulation material 1 for a liquid hydrogen tank used for the liquid hydrogen tank pooling the liquid hydrogen comprises a foam layer 2 and a conductive layer 3 provided on the foam layer 2 and including an electric conductive material.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a liquid hydrogen tank insulation material used in a liquid hydrogen tank that stores liquid hydrogen, a liquid hydrogen tank, and a method for installing the insulation material. [Background technology]

[0002] Cryogenic tanks are widely used to store flammable liquefied gases such as liquefied natural gas (LNG), liquefied ethylene gas (LEG), and liquefied petroleum gas (LPG). Cryogenic tanks include an inner tank for storing the flammable liquefied gas, and a heat insulating layer is provided on the outer wall surface of the inner tank to keep the flammable liquefied gas stored in the inner tank cool (see, for example, Patent Documents 1 and 2). Large cryogenic tanks are provided with a liquid containment dike that encloses the inner tank to prevent the contents from leaking out to the surrounding area in the event of an accident.

[0003] In conventional cryogenic tanks, the liquid barrier is installed so that it encases the inner tank, making the space between the cryogenic tank and the liquid barrier an airtight space that is shut out from the outside air, and is filled with insulation material mainly made of granular perlite and glass wool, and nitrogen gas. In conventional cryogenic tanks, a cold and heat resistance mitigation material made of rigid polyurethane foam (PUF) is installed on the inside of the liquid barrier to protect the liquid barrier from cold and heat in the unlikely event that the contents leak. The cold and heat resistance mitigation material is required to have both insulation performance and liquid tightness, and glass cloth is glued to the surface to prevent cracks caused by cold and heat. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5249093 [Patent Document 2] Patent No. 5174856 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if conventional cryogenic tanks are repurposed to store liquid hydrogen, the risk of explosion increases for the following reasons: First, the ignition energy of hydrogen is only 1 / 10 that of hydrocarbons, and its explosive range is extremely wide, ranging from 4.0 to 75.6 vol%. Next, inert nitrogen gas is sealed in the space between the cryogenic tank and the dike to prevent combustion, but since the boiling point of liquid hydrogen is lower than that of nitrogen, nitrogen gas would liquefy if liquid hydrogen was stored in the cryogenic tank, so nitrogen gas cannot be used.As there is no suitable gas to replace nitrogen, it is being considered to adopt a system in which the space between the cryogenic tank and the dike is not sealed, and liquid hydrogen that leaks from the cryogenic tank is vaporized between the cryogenic tank and the dike and released into the atmosphere. For the above reasons, if liquid hydrogen stored in a liquid hydrogen tank leaks, the leaked liquid hydrogen will vaporize and mix with the atmosphere, easily reaching the explosion range. In addition, the mixture of vaporized hydrogen and air may generate static electricity due to friction with the heat and cold resistance mitigation material as it flows between the liquid hydrogen tank and the liquid barrier, and there is a very high risk of an explosion due to the static electricity generated by hydrogen, which has low ignition energy.

[0006] Therefore, an object of the present invention is to provide an insulating material for a liquid hydrogen tank, a liquid hydrogen tank, and a method for installing the insulating material, which suppress the generation of static electricity in liquid hydrogen stored in the liquid hydrogen tank and reduce the risk of explosion due to static electricity. [Means for solving the problem]

[0007] The present invention relates to the following items [1] to [9]. [1] An insulating material for a liquid hydrogen tank used in a liquid hydrogen tank that stores liquid hydrogen, the insulating material for a liquid hydrogen tank comprising: a foam layer; and a conductive layer provided on the foam layer and comprising a conductive material. [2] The insulating material for a liquid hydrogen tank according to [1], wherein the foam layer is urethane foam. [3] The insulating material for a liquid hydrogen tank according to [1] or [2], wherein the conductive layer is formed from an aluminum glass cloth. [4] An insulating material for a liquid hydrogen tank according to any one of [1] to [3], which is arranged on the inner peripheral side of a liquid containment dike provided around the liquid hydrogen tank. [5] An insulating material for a liquid hydrogen tank according to any one of [1] to [4], which is arranged on the inner peripheral surface side of an inner vessel of the liquid hydrogen tank. [6] A liquid hydrogen tank comprising an insulating material for a liquid hydrogen tank as described in any one of [1] to [5], a tank body in which hydrogen is stored, and a liquid barrier surrounding the tank body, wherein the insulating material for a liquid hydrogen tank is positioned on the inner surface side of the liquid barrier. [7] A liquid hydrogen tank as described in [6], wherein the space between the tank body and the liquid barrier is an open space. [8] A liquid hydrogen tank comprising an insulating material for a liquid hydrogen tank according to any one of [1] to [5] and an inner tank in which hydrogen is stored, the insulating material for a liquid hydrogen tank being disposed on the inner peripheral surface side of the inner tank. [9] A method for applying insulation material to a construction surface of a liquid hydrogen tank, comprising the steps of: preparing an application machine having a guide rail and a molding device having a pressure plate and a discharge port and capable of moving up and down along the guide rail; positioning the application machine so as to form an injection space between the construction surface and the pressure plate; supplying a surface material containing a conductive material so as to follow the inner surface of the pressure plate facing the construction surface; and injecting foam concentrate into the injection space from the discharge port so that the surface material is bonded and integrated with the foam layer to obtain an insulation material. Effect of the Invention

[0008] The present invention can provide an insulating material for a liquid hydrogen tank, a liquid hydrogen tank, and an insulating material installation method that suppress the generation of static electricity in liquid hydrogen stored in the liquid hydrogen tank and reduce the risk of explosion due to static electricity. [Brief description of the drawings]

[0009] [Figure 1]1 is a cross-sectional view of an insulating material for a liquid hydrogen tank according to an embodiment of the present invention. FIG. [Diagram 2] 1 is a schematic side view showing an application position of a liquid hydrogen tank insulating material according to an embodiment of the present invention to a liquid hydrogen tank. FIG. [Diagram 3] 1 is a schematic side view showing an application position of a liquid hydrogen tank insulating material according to an embodiment of the present invention to a liquid hydrogen tank. FIG. [Figure 4] 1 is a schematic side view showing an application position of a liquid hydrogen tank insulating material according to an embodiment of the present invention to a liquid hydrogen tank. FIG. [Diagram 5] FIG. 1 is a schematic side view showing a construction machine according to an embodiment of the present invention. [Figure 6] FIG. 2 is a schematic rear view showing the construction machine according to the embodiment of the present invention. [Figure 7] FIG. 2 is a schematic perspective view for explaining a form construction method according to an embodiment of the present invention. [Figure 8] FIG. 2 is a schematic perspective view for explaining a form construction method according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are represented by the same or similar reference numerals.

[0011] [Insulation material for liquid hydrogen tanks] 1, a liquid hydrogen tank insulating material 1 according to an embodiment of the present invention includes a foam layer 2 and a conductive layer 3 made of a conductive material and provided on the foam layer 2. Hereinafter, the liquid hydrogen tank insulating material 1 according to an embodiment of the present invention will be described in detail with reference to the embodiment.

[0012] First, a representative example of a liquid hydrogen tank 10 in which the insulating material 1 for a liquid hydrogen tank is used as a cold resistance mitigation material will be briefly described with reference to FIG. 2. As shown in FIG. 2, the liquid hydrogen tank 10 is a double tank, and includes a tank body consisting of an inner tank 11 and an outer tank 12. The inner tank 11 is a pressure vessel made of low-temperature materials such as nickel steel and aluminum alloys, which have a low brittle transition temperature, and liquid hydrogen is stored in the inner tank 11. The inner tank 11 is installed on a bottom cold insulation layer 15 provided on the bottom surface of the outer tank 12. The outer tank 12 is a pressure vessel made of room-temperature materials such as iron and carbon steel, and is provided so as to surround the inner tank 11. Between the outer peripheral surface of the inner tank 11 and the inner peripheral surface of the outer tank 12, a space A, which is a sealed space, is provided, and the space A functions as a vacuum insulation layer by being depressurized to become a vacuum.

[0013] 2, a liquid hydrogen tank 10 according to an embodiment of the present invention comprises a liquid hydrogen tank insulation material 1, an inner tank 11, an outer tank 12 provided to surround the inner tank 11, and a liquid barrier dike 13 surrounding the outer tank 12 (i.e., the tank body), with the liquid hydrogen tank insulation material 1 being disposed on the inner circumferential surface 13A side of the liquid barrier dike 13. In this embodiment, the tank body of the liquefied hydrogen tank 10 has a double structure and is vacuum insulated, and the liquid hydrogen tank insulation material 1 disposed on the inner circumferential surface 13A of the liquid barrier dike 13 is used as a cold and heat resistance mitigation material for protecting the liquid barrier dike 13. The dike 13 prevents the liquid hydrogen contained in the liquid hydrogen tank 10 from leaking out into the surrounding area in the unlikely event of an accident. The dike 13 is formed, for example, of a reinforced concrete structure and an earth mound structure. The liquid hydrogen tank 10 is placed on a foundation 14 provided on the bottom surface of the dike 13. The foundation 14 is formed, for example, of concrete. Between the outer tank 12 and the dike 13, an open space, space B, is provided, and liquid hydrogen leaking from the liquid hydrogen tank 10 is vaporized and released into the atmosphere from the open part of space B.

[0014] As shown in Fig. 2, the liquid hydrogen tank insulating material 1 of the present invention is disposed on the inner peripheral surface 13A side of a liquid barrier 13 provided around a liquid hydrogen tank 10. By disposing the liquid hydrogen tank insulating material 1 on the inner peripheral surface 13A side of the liquid barrier 13, when liquid hydrogen leaks from the liquid hydrogen tank 10 and vaporizes in space B and is released into the atmosphere, static electricity generated by friction with the liquid hydrogen tank insulating material 1 is discharged by the conductive layer 3, reducing the risk of explosion. From the viewpoint of improving the efficiency of discharging static electricity generated when vaporized hydrogen gas is released into the atmosphere, the liquid hydrogen tank insulating material 1 has the conductive layer 3 disposed on the inner peripheral side and the foam layer 2 disposed on the outer peripheral side.

[0015] 3, a liquid hydrogen tank 10 according to another embodiment of the present invention includes a liquid hydrogen tank insulation material 1 serving as a material for suppressing heat input to liquid hydrogen, and an inner tank 11, with the liquid hydrogen tank insulation material 1 being disposed on the inner circumferential surface 11A side of the inner tank 11. In this embodiment, the tank body of the liquefied hydrogen tank 10 has a single-layer structure, and the liquid hydrogen tank insulation material 1 disposed on the inner circumferential surface 11A of the inner tank 11 constituting the tank body is used as a material for suppressing heat input to liquid hydrogen. By disposing the liquid hydrogen tank insulation material 1 on the inner circumferential surface 11A side of the inner tank 11 of the liquid hydrogen tank 10, if static electricity is generated within the inner tank 11 of the liquid hydrogen stored in the liquid hydrogen tank 10, the static electricity is discharged by the conductive layer 3, reducing the risk of explosion. From the viewpoint of improving the efficiency of discharging static electricity generated within the inner tank 11, the liquid hydrogen tank insulation material 1 has the conductive layer 3 disposed on the inner circumferential side and the foam layer 2 disposed on the outer circumferential side.

[0016] 4, the liquid hydrogen tank insulation material 1 of the present invention may be disposed on both the inner circumferential surface 13A side of the liquid barrier dike 13 provided around the liquid hydrogen tank 10, and the inner circumferential surface 11A side of the inner tank 11 of the liquid hydrogen tank 10. In this embodiment, the tank body of the liquefied hydrogen tank 10 has a single-layer structure, and the liquid hydrogen tank insulation material 1 disposed on the inner circumferential surface 11A of the inner tank 11 constituting the tank body is used as a material for suppressing heat input to the liquid hydrogen, and the liquid hydrogen tank insulation material 1 disposed on the inner circumferential surface 13A of the liquid barrier dike 13 is used as a material for reducing cold and heat resistance to protect the liquid barrier dike 13. By placing it on both the inner surface 13A side of the liquid barrier 13 and the inner surface 11A side of the inner tank 11, the static electricity discharge efficiency can be further improved, and the risk of explosion can be further reduced.

[0017] (Foam layer) Examples of the foam layer 2 constituting the insulating material 1 for a liquid hydrogen tank of the present invention include urethane foam, phenol foam, and styrene foam, and from the standpoints of insulating properties, ease of manufacture, and hardening speed, urethane foam and phenol foam are preferred, and urethane foam is more preferred.

[0018] When the insulating material 1 for a liquid hydrogen tank is used as a material for reducing the heat and cold resistance of the liquid barrier 13, the thickness of the foam layer 2 is not particularly limited, but is, for example, 5 to 200 mm, preferably 20 to 150 mm, and more preferably 30 to 100 mm. When the insulating material 1 for a liquid hydrogen tank is used on the inner circumferential surface 11A of the inner tank 11 as a material for suppressing heat input to the liquid hydrogen, the thickness of the foam layer 2 is not particularly limited, but is, for example, 200 to 1,000 mm, preferably 300 to 800 mm, and more preferably 400 to 600 mm.

[0019] <Urethane foam> The urethane foam constituting the foam layer 2 will be described in more detail. The urethane foam used in this embodiment is formed by curing and foaming a urethane resin composition. The urethane resin contained in the urethane foam is a reaction product obtained by mixing and reacting a polyisocyanate compound and a polyol compound.

[0020] The density of the urethane foam is not particularly limited, but is preferably 20 to 120 kg / m 3 It is preferable that the density is in the range of 120 kg / m 3 By setting the thickness below 20kg / m, the thermal conductivity of the urethane foam becomes appropriate and the required thermal insulation performance can be obtained. 3 By setting the density to 25 to 100 kg / m or more, it becomes easier to achieve the desired strength. From these viewpoints, the density of the urethane foam is set to 25 to 100 kg / m 3 More preferably, the range is 30 to 80 kg / m 3 It is more preferable that the density of the urethane foam is in the range of 9. The density of the urethane foam can be measured in accordance with JIS K7222.

[0021] (Conductive layer) The conductive layer 3 constituting the liquid hydrogen tank insulation material 1 of the present invention comprises a conductive material and suppresses the generation of static electricity in the liquid hydrogen stored in the liquid hydrogen tank 10. Examples of conductive materials used for the conductive layer 3 include metal mesh materials such as stainless steel, iron, and copper, and metal foils such as aluminum foil and copper foil, and any of these may constitute the conductive layer 3. The conductive layer 3 may also be formed from a composite material of a conductive material and a material other than the conductive material. Examples of composite materials include metal foil composites such as aluminum glass cloth, which is a composite of metal foil and glass cloth.

[0022] From the viewpoints of electrical conductivity and ease of lamination, metal foil and aluminum glass cloth are preferred, and aluminum glass cloth is more preferred, as materials used to form the conductive layer 3. Aluminum glass cloth generally has a laminated structure of metal foil and glass cloth. When using an aluminum glass cloth, the metal foil may be placed on the foam layer 2 side (i.e., the outer periphery side of the liquid hydrogen tank) and the glass cloth on the opposite side to the foam layer 2 (i.e., the inner periphery side of the liquid hydrogen tank), but it is preferable that the metal foil is placed on the opposite side to the foam layer 2 and the glass cloth is placed on the foam layer 2 side. Placing the metal foil on the opposite side to the foam layer 2 (i.e., the inner periphery side of the liquid hydrogen tank) can further improve the efficiency of discharging static electricity. Note that this configuration can also be said to be a structure in which the conductive layer 3 is laminated to the foam layer via the glass cloth. Furthermore, even when a material other than aluminum glass cloth is used, a material other than the conductive layer 3 may be provided between the conductive layer 3 and the foam layer 2, and a structure in which a material other than aluminum glass cloth is used and a glass cloth and a conductive layer 3 (e.g., a metal foil) are provided in that order on top of the foam layer 2 may be used.

[0023] The thickness of the conductive layer 3 is not particularly limited, but is, for example, 0.005 to 2 mm, preferably 0.01 to 1.5 mm, and more preferably 0.01 to 1 mm. Furthermore, the thickness of the material other than the conductive layer 3, such as glass cloth, provided between the conductive layer 3 and the foam layer is, for example, 0.1 to 3 mm, preferably 0.1 to 2 mm, and more preferably 0.1 to 1 mm.

[0024] [Construction method] Next, a method for constructing the insulating material 1 for a liquid hydrogen tank according to an embodiment of the present invention will be described. In the following description, the inner peripheral surface 13A of the liquid barrier 13 is the construction surface on which the insulating material 1 for a liquid hydrogen tank is constructed. In the following description, the side on which the construction surface is provided is referred to as the front, and the opposite side as the rear, as viewed from the construction machine.

[0025] 5 and 6, an application machine 18 that applies the liquid hydrogen tank insulation material 1 of this embodiment includes a guide rail 19 and a forming device 20 that can be raised and lowered along the guide rail 19. The application machine 18 also includes a lifting device 40 that raises and lowers the forming device 20. The forming device 20 includes a foam concentrate discharge device 21, a presser plate 25, and the like. The foam concentrate discharge device 21 is a device for supplying foam concentrate R, and includes a discharge port 22 that discharges the foam concentrate R. The foam concentrate discharge device 21 is capable of moving the discharge port 22 in the lateral direction (the direction perpendicular to the paper surface of FIG. 5).

[0026] The foam stock solution R supplied from foam stock solution discharger 21 is a liquid for forming foam layer 2, and becomes a foam (foam layer 2) by foaming and curing. For example, in the case of urethane foam, the foam stock solution contains a polyisocyanate component, a polyol component, a blowing agent, a foam stabilizer, a catalyst, etc. Such foam stock solution is prepared, for example, in foam stock solution discharger 21, by mixing a polyisocyanate component (second liquid) with a first liquid consisting of a polyol component blended with a blowing agent, a foam stabilizer, a catalyst, etc.

[0027] The pressure plate 25 is disposed so as to be spaced apart from the construction surface (the inner peripheral surface 13A of the liquid barrier 13), thereby forming an injection space S between the pressure plate 25 and the construction surface (the inner peripheral surface 13A) on the front side of the construction machine 18. The injection space S is a space into which the foam concentrate is injected. The discharge port 22 is disposed forward of the pressure plate 25, thereby being disposed above the injection space S.

[0028] The forming device 20 is further equipped with a winding roll 26, a supply roll 27, etc. The face material 17 is wound around the winding roll 26. The supply roll 27 is disposed above the pressure plate 25. The face material 17 is unwound from the winding roll 26, guided by the supply roll 27, and supplied from the upper part of the injection space S toward the injection space S. In the injection space S, the face material 17 is disposed so as to follow the inner surface 25A of the pressure plate 25 that faces the application surface. Depending on the type of face material 17, an uncoiler or the like may be provided to appropriately adjust the supply speed when the face material 17 is unwound from the winding roll 26.

[0029] The surface material 17 has a conductive material. The surface material 17 is generally a sheet-like or film-like member. The surface material 17 may be made of a single conductive material, and may be, for example, a metal foil or a metal mesh as described above. The surface material 17 may also be a composite material of a conductive material and another material. A specific example of a suitable composite material is aluminum glass cloth as described above. In addition, when the surface material 17 has a laminated structure of a conductive material such as aluminum glass cloth and a material other than the conductive material, the conductive material may be arranged on the pressure plate side, or a material other than the conductive material may be arranged on the pressure plate side, but it is preferable that the conductive material is arranged on the pressure plate side.

[0030] The forming device 20 is mounted on a gondola 29, and the elevating device 40 elevates the gondola 29, thereby elevating the forming device 20. The gondola 29 is slidably attached to a guide rail 19. A pair of guide rails 19 are provided, for example, in the horizontal direction. The elevating device 40 is disposed above the gondola 29, and supports the gondola 29 by suspending it via a wire 31, for example, and elevates and lowers the gondola 29 along the guide rail 19 by winding up and unwinding the wire 31. A pair of wires 31 are provided, for example, in the horizontal direction. The lifting device 40 has a traveling mechanism 42 for traveling laterally along the hanging rail 41. This allows the forming device 20 to be moved laterally by the lifting device 40.

[0031] As shown in FIG. 6, a reinforcing bar 37 may be provided between the pair of guide rails 19, 19.

[0032] Next, a method for applying the insulation material 1 for a liquid hydrogen tank using the application machine 18 will be described in more detail. In applying the foam layer 2, first, as shown in Figures 5 and 7, the application machine 18 is placed in the space B so as to form an injection space S between the pressing plate 25 and the application surface (inner peripheral surface 13A) as described above. At this time, leakage prevention members 35A, 35B, and 35C are placed at the bottom and both sides of the injection space S, respectively, as shown in Figure 7, and the bottom and both sides of the injection space S are sealed by the leakage prevention members 35A, 35B, and 35C. The leakage prevention members 35A, 35B, and 35C are formed of, for example, tubes.

[0033] The tube is expanded by supplying air to the inside thereof using an air pump or the like, and in this expanded state, the bottom or either of both sides of the injection space S may be sealed. There are no particular limitations on the material of the tube, and a material with excellent mold release properties, such as fluororesins such as tetrafluoroethylene and difluoroethylene, or silicone resin, may be used. In addition, a surface material with excellent mold release properties, such as fluororesin or silicone resin, may be attached to the surface of the resin tube, or the surface of the resin tube may be subjected to a mold release treatment using a mold release agent such as silicone resin. Furthermore, the air tube may be a resin water supply hose reinforced with glass fiber.

[0034] The liquid leakage prevention members 35B, 35C on both sides may be suspended from, for example, an elevator device 40. The liquid leakage prevention members 35B, 35C on both sides may be fed from a tube supply mechanism (not shown) mounted on the gondola 29, and air may be injected into the liquid leakage prevention members 35B, 35C and supplied to both sides of the injection space S. The lower liquid leakage prevention member 35A may use a tube into which air has been injected beforehand.

[0035] After the injection space S is sealed as described above and the facing material 17 is aligned along the inner surface 25A of the pressing plate 25, foam raw solution R is injected into the injection space S through the discharge port 22. At this time, it is preferable to move the discharge port 22 back and forth laterally, as shown in Fig. 7. The foam raw solution R injected into the injection space S is foamed and hardened, and is bonded to and integrated with the facing material 17 arranged along the inner surface 25A, and is also bonded to the inner surface 13A of the liquid barrier 13, forming the liquid hydrogen tank insulation material 1 comprising the foam layer 2 and the conductive layer 3 on the inner surface 13A of the liquid barrier 13.

[0036] When injection of the foam raw solution R into the injection space S begins, the elevating device 40 raises the molding device 20 along the guide rail 19. As a result, the foam layer 2 is formed from the bottom to the top on the inner circumferential surface 13A of the liquid barrier 13. In addition, the face material 17 is continuously unwound from the winding roll 26, and the conductive layer 3 composed of the face material 17 is laminated on the foam layer 2. The liquid hydrogen tank insulation material 1, in which the foam layers 2 and conductive layers 3 applied as described above are laminated, has a length approximately equal to the width of the pressure plate 25. If foam layers 2 of that length are considered to be one row, when application of one row of liquid hydrogen tank insulation material 1 is completed, the forming device 20, together with the lifting device 40, is moved laterally along the hanging rail 41 to form the next row of liquid hydrogen tank insulation material 1. Then, application of the liquid hydrogen tank insulation material 1 is repeated to form the liquid hydrogen tank insulation material 1 around the entire circumference of the liquid retaining dike 13.

[0037] In addition, the lower liquid leakage prevention member 35A is positioned even lower than the lower end of the foam layer 2 being formed, and moves away from the lower end of the pressure plate 25 as the molding device 20 rises. However, as shown in Figure 8, the lower part of the injection section S is occupied by the foam raw liquid R or the foam layer 2 formed by foaming, so that the foam raw liquid R does not leak from the lower part of the injection section S. Furthermore, as described above, when installing the insulating material 1 for the first row of liquid hydrogen tanks, the liquid leakage prevention members 35B, 35C were arranged on both sides of the injection space S, but when installing the insulating material 1 for the second or subsequent rows of liquid hydrogen tanks, one side of the injection space S only needs to be sealed with the insulating material 1 for the liquid hydrogen tanks that has already been installed, so one of the liquid leakage prevention members 35B, 35C can be omitted. Furthermore, when installing the insulating material 1 for the final row of liquid hydrogen tanks, both sides are sealed by the insulating material 1 for the first row of liquid hydrogen tanks and the insulating material 1 for the liquid hydrogen tank one row before the final row, so the liquid leakage prevention members 35B, 35C on both sides can be omitted. Also, for example, after the first row is installed, the third row of insulation material 1 for the liquid hydrogen tank is installed at a distance, and then the second row of insulation material 1 for the liquid hydrogen tank is installed, so that when the second row of insulation material 1 for the liquid hydrogen tank is installed, both sides can be sealed with the already installed insulation material 1 for the liquid hydrogen tank. Therefore, with this method, both of the liquid leakage prevention members 35B and 35C can be omitted.

[0038] [Other embodiments] The construction method described above by showing the embodiments is not limited to the configuration of the above embodiments, and various improvements and modifications are possible without departing from the spirit of the present invention, and components may be added as appropriate. For example, in the above explanation, an example has been given in which the construction machine 18 injects foam concentrate while moving upward to form the foam layer 2, and then supplies the facing material 17 onto the formed foam layer 2 to form the conductive layer 3, thereby constructing the liquid hydrogen tank insulation material 1 as a single unit, but the present invention is not limited to this. A construction method may also be used in which the foam concentrate is sprayed onto the entire surface to be constructed to form the foam layer 2, the surface of the foam layer 2 is then cut and smoothed, and the conductive layer 3 is formed on the smoothed surface.

[0039] In the above description, an example has been shown in which the surface material 17 having a conductive material is supplied to form the conductive layer 3, but the present invention is not limited to this, and a material other than a conductive material may be supplied as the surface material 17. For example, glass cloth, which is a material other than a conductive material, may be supplied as the surface material 17, and the conductive layer 3 may be formed by later attaching a metal foil onto the glass cloth.

[0040] Alternatively, a construction method may be used in which the insulating material 1 for a liquid hydrogen tank is prepared in advance by laminating the conductive layer 3 on the foam layer 2, and then the insulating material 1 is installed at a desired location.

[0041] In the above description, the liquid leakage prevention members 35A, 35B, and 35C are tubes, but they may be foam molded products, release sheets, etc. The foam molded product is, for example, urethane foam. When using a release sheet as a liquid leakage prevention member, the face material supplied along the inner surface 25A of the pressing plate 25 as described above may be used as the release sheet, and the release sheet may be used as the liquid leakage prevention member. Specifically, at least one of both side portions or the tip portion of the release sheet supplied along the inner surface 25A of the pressing plate 25 may be folded to be used as a member that seals either one of both side portions or the bottom portion of the casting space S. When folding the sides of the release sheet, for example, a folding mechanism that folds both sides of the release sheet may be provided between the supply roll 27 and the casting space S. Furthermore, a release sheet may be supplied from a release sheet supply roll (not shown) provided separately from the winding roll 26 so as to cover the side of the injection space S, in addition to the facing material. Furthermore, the liquid leakage prevention members 35A, 35B, and 35C may be other than foam molded products, tubes, and release sheets, and may be, for example, foam sheets or release sheets attached to the outer peripheral surface of a frame material. The above-mentioned foam molded products, tubes, release sheets, frame materials, and the like may be used in appropriate combination. For example, the lower liquid leakage prevention member 35A and the side liquid leakage prevention members 35B and 35C may be different materials. The liquid leakage prevention members 35B and 35C may be attached to the construction surface detachably by magnets or the like.

[0042] In addition, in order to improve the thickness accuracy of the foam layer 2, the construction machine 18 described above may be further equipped with a reaction force absorbing device described in JP 2020-190139 A. [Explanation of symbols]

[0043] 1. Insulation material for liquid hydrogen tanks 2 Foam Layer 3 Conductive layer 10 Liquid hydrogen tank 11 Inner tank 11A Outer surface (rear surface) 12 Outer tank 13 Liquid dike 13A Inner surface (front surface) 14 Basics 15 Bottom cold layer 18 Construction equipment 19 Guide rail 20 Molding equipment 22 Discharge port 25 Presser plate 29 Gondola 35A, 35B, 35C Leak prevention parts 40 Lifting device 41 Suspension rail R Foam Stock Solution S injection space

Claims

1. A thermal insulating material for a liquid hydrogen tank used in a liquid hydrogen tank for storing liquid hydrogen, A foam layer; a conductive layer disposed on the foam layer and comprising a conductive material; A thermal insulation material for a liquid hydrogen tank, the conductive layer being formed from a metal foil or a metal foil composite (excluding those having on their surface a cured layer of silicone resin paint containing dispersed conductive material).

2. 2. The insulating material for a liquid hydrogen tank according to claim 1, wherein the foam layer is a urethane foam.

3. 3. The insulating material for a liquid hydrogen tank according to claim 1, wherein the conductive layer is formed of an aluminum glass cloth.

4. 4. The insulating material for a liquid hydrogen tank according to claim 1, which is arranged on the inner peripheral side of a liquid retaining dike provided around the liquid hydrogen tank.

5. 5. The insulating material for a liquid hydrogen tank according to claim 1, which is arranged on an inner peripheral surface side of an inner vessel of the liquid hydrogen tank.

6. A liquid hydrogen tank comprising an insulating material for a liquid hydrogen tank according to any one of claims 1 to 5, a tank body in which hydrogen is stored, and a liquid barrier surrounding the tank body, wherein the insulating material for a liquid hydrogen tank is disposed on the inner surface side of the liquid barrier.

7. 7. The liquid hydrogen tank according to claim 6, wherein an open space is provided between the tank body and the liquid barrier.

8. A liquid hydrogen tank insulating material according to any one of claims 1 to 5, and an inner tank in which hydrogen is stored, The liquid hydrogen tank, wherein the liquid hydrogen tank insulation material is disposed on the inner peripheral surface side of the inner tank.

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