Liquid hydrogen storage tank

Abstract

This liquid hydrogen storage tank comprises a tank body, a liquid blocking barrier, and piping. The tank body includes: an inner tank that stores liquid hydrogen; and an outer tank that is formed outside the inner tank with a cooling layer disposed therebetween. The liquid blocking barrier includes a concrete structure erected so as to surround the outer circumference of the tank body. The piping passes through the tank body and the liquid blocking barrier and supplies the liquid hydrogen stored in the inner tank to the outside. The liquid blocking barrier includes a reinforcement portion for reinforcing the strength of a penetration portion through which the piping passes.

Description

Liquefied hydrogen storage tank

[0001] The present disclosure relates to a tank for storing liquefied hydrogen.

[0002] Liquefied gas storage tanks are known as storage facilities for low-temperature liquefied gases, such as liquefied hydrogen and liquefied natural gas. The tank includes a flat-bottomed tank body that stores the liquefied gas and a dike surrounding the tank body. The dike is constructed to prevent the stored liquefied gas from leaking out into the surrounding area in the event of damage to the tank body. Liquefied gas storage tanks are equipped with a pump for discharging the liquefied gas from the tank body (see, for example, Patent Document 1).

[0003] When the liquefied gas to be stored is liquefied hydrogen, it may be difficult to install the pump inside the inner tank of the tank body due to the difficulty of maintenance work, etc. In this case, a pipe must be installed that penetrates the tank body and the liquid barrier, and the liquefied hydrogen stored in the tank body will be dispensed through this pipe.

[0004] The dike is generally made of concrete. However, if liquefied hydrogen leaks from the inner tank, hydraulic pressure acts on the dike in a direction that expands the diameter of the dike. This hydraulic pressure causes tensile stress to act on the dike in the circumferential direction. Therefore, if the dike has a penetration through which the piping passes, the penetration will become a weak point in terms of strength where stress is more likely to concentrate than in other parts when tensile stress occurs during the leakage.

[0005] Japanese Patent Application Laid-Open No. 2017-132619

[0006] The object of the present disclosure is to provide a liquefied hydrogen storage tank comprising a tank body and a concrete-structured liquid barrier, which can suppress weakening of the penetration portion where the piping for discharging liquefied hydrogen passes through the liquid barrier.

[0007] A liquefied hydrogen storage tank according to one aspect of the present disclosure comprises a tank body including an inner tank for storing liquefied hydrogen and an outer tank formed between the inner tank and the outer tank with a cold insulation layer interposed therebetween, a concrete liquid barrier erected so as to surround the outer periphery of the tank body, and a pipe penetrating the tank body and the liquid barrier for discharging the liquefied hydrogen stored in the inner tank to the outside. The liquid barrier includes a reinforcing portion for reinforcing the strength of the penetration portion through which the pipe passes.

[0008] According to the liquefied hydrogen storage tank of the present disclosure, in a liquefied hydrogen storage tank comprising a tank body and a concrete-structured liquid barrier, weakening of the penetration portion where the piping for discharging liquefied hydrogen passes through the liquid barrier can be suppressed.

[0009] Fig. 1 is a cross-sectional view showing a liquefied hydrogen storage tank according to an embodiment of the present disclosure. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. Fig. 3 is a perspective view showing a first example of a reinforcing part incorporated into a piping penetration part of a liquid barrier dike. Fig. 4 is a perspective view showing a second example of the reinforcing part. Fig. 5A is a perspective view showing a third example of the reinforcing part. Fig. 5B is a perspective view showing a fourth example of the reinforcing part.

[0010] [Overall Tank Structure] An embodiment of a liquefied hydrogen storage tank according to the present disclosure will now be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a liquefied hydrogen storage tank 1 according to an embodiment of the present disclosure, and FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1. The liquefied hydrogen storage tank 1 is a multi-shell tank that stores liquefied hydrogen LH. The liquefied hydrogen storage tank 1 includes a tank body 10 having a multi-shell structure, a liquid barrier 2 erected to surround the outer periphery of the tank body 10, a pump 3 that discharges liquefied hydrogen LH from the tank body 10 to the outside, and a chamber 51 for the pump 3 located within the structure of the liquid barrier 2. FIG. 1 illustrates a double-shell tank as an example of a multi-shell tank.

[0011] The tank body 10 is a flat-bottom tank having a storage space 10A for storing liquefied hydrogen LH, and includes an outer tank 11 erected on a tank foundation 21, an inner tank 12 enclosed within the outer tank 11, and a cold insulation layer 13 disposed between the outer tank 11 and the inner tank 12. The tank foundation 21 is a concrete layer that forms the foundation of the tank body 10 and the dike 2. The outer tank 11 and the inner tank 12 both have a circular shape when viewed from above and are arranged concentrically. The tank body 10 may also be a multi-shell tank provided with an intermediate tank between the outer tank 11 and the inner tank 12.

[0012] The outer tank 11 is a sealed body made of metal such as carbon steel or stainless steel, and includes an outer tank bottom plate 11B, outer tank side plates 11S, and an outer tank roof 11R. The outer tank bottom plate 11B is laid directly on the tank foundation 21 and has a disk-like shape. The outer tank side plate 11S is erected from the periphery of the outer tank bottom plate 11B and has a cylindrical shape. The outer tank roof 11R is attached to the upper end of the cylindrical outer tank side plate 11S so as to cover the upper opening of the outer tank side plate 11S and has a dome-like shape.

[0013] The inner tank 12 is a tank that forms the storage space 10A that actually stores the liquefied hydrogen LH. The inner tank 12 is a sealed body made of a metal such as stainless steel, and is surrounded by the outer tank 11 via a predetermined space that serves as the cold insulation layer 13. The inner tank 12 includes an inner tank bottom plate 12B, inner tank side plates 12S, and an inner tank roof 12R. The inner tank bottom plate 12B has a disk-like shape with a smaller diameter than the outer tank bottom plate 11B. The inner tank side plate 12S stands upright from the periphery of the inner tank bottom plate 12B and has a cylindrical shape. The inner tank roof 12R is attached to the upper end of the inner tank side plate 12S and has a dome-like shape. Liquefied hydrogen LH is stored inside the inner tank 12, and gas vaporized from the liquefied hydrogen LH accumulates in the upper layer of the inner tank 12.

[0014] The cold insulation layer 13 utilizes the gap between the outer tub 11 and the inner tub 12 as an insulating space to improve the cold insulation of the inner tub 12. The cold insulation layer 13 may contain powder insulation material or solid insulation material. For example, the gap between the outer tub roof 11R and the inner tub roof 12R is filled with powder insulation material such as granular perlite. The gap between the outer tub side plate 11S and the inner tub side plate 12S is filled with granular perlite and glass wool. The gap between the outer tub bottom plate 11B and the inner tub bottom plate 12B is filled with insulating blocks such as foam glass.

[0015] The cold insulation layer 13 is filled with hydrogen gas, helium gas, nitrogen gas, or the like, together with a cold insulation material such as granular perlite. The gas to be filled preferably has a boiling point equal to or lower than that of the stored liquefied hydrogen LH, and from this perspective, hydrogen gas or helium gas is preferable. For example, a communication pipe may be provided to communicate the internal space of the inner tank 12 with the space of the cold insulation layer 13, and the vaporized gas of the stored liquefied hydrogen LH may be introduced into the cold insulation layer 13.

[0016] The dike 2 prevents the stored liquefied hydrogen LH from leaking out to the surrounding area in the event of damage to the tank body 10. The dike 2 is a cylindrical prestressed concrete (PC) structure constructed on the tank foundation 21 and erected to surround the outer periphery of the tank body 10. The dike 2 of this embodiment has a structure in which there is no separation distance between it and the outer periphery of the tank body 10, i.e., the dike 2 and the outer tank side plate 11S are integrated. In the event of damage to the tank body 10, the dike 2 prevents leakage of the liquefied hydrogen LH, and the liquefied hydrogen LH is retained in the space of the cold insulation layer 13. In other words, the space inside the outer periphery 2A of the dike 2 serves as a storage space for the leaked liquefied hydrogen LH. The dike 2 may be a concrete structure other than a PC structure, such as a reinforced concrete structure.

[0017] The dike 2 has an outer peripheral surface 2A exposed to the outside and an inner peripheral surface 2B in contact with the outer tank side plate 11S. The dike 2 features a ring-shaped portion 22 and a protruding portion 23. The ring-shaped portion 22 is a cylindrical dike that surrounds the entire outer periphery of the tank body 10. Figure 1 shows an example in which the height of the ring-shaped portion 22 is approximately the same as the height of the outer tank side plate 11S. The protruding portion 23 is a rectangular parallelepiped structural portion provided corresponding to the location of the pump 3, with a portion of the ring-shaped portion 22 protruding radially outward. As shown in Figure 2, the outer peripheral surface 2A of the dike 2 bulges radially outward at the location where the protruding portion 23 is formed. The shape of the protruding portion 23 is not limited and may be a shape including a curved surface, such as a cylindrical or elliptical cylindrical shape.

[0018] The pump 3 is disposed on the side of the tank body 10 and inside the protrusion 23, and generates a pumping force to discharge the liquefied hydrogen LH in the inner tank 12 to the outside through the side plates of the tank body 10. In this embodiment, the side plates are the inner tank side plate 12S and the outer tank side plate 11S. An extraction pipe 31 and a discharge pipe 32 are connected to the pump 3.

[0019] The extraction pipe 31 is a straight pipe that penetrates the side plate of the tank body 10 and the side of the dike 2 and dispenses the liquefied hydrogen LH stored in the inner tank 12. The extraction pipe 31 is a conduit that penetrates from the outside of the tank body 10 through the outer tank side plate 11S, the cold insulation layer 13, and the inner tank side plate 12S to the storage space 10A of the inner tank 12. One end of the extraction pipe 31 faces the liquefied hydrogen LH stored in the inner tank 12, and the other end is connected to the inlet end of the pump 3. The dispensing pipe 32 is a conduit that extends upward inside the protruding portion 23, passes over the top surface 23T of the protruding portion 23, and reaches the outside of the liquefied hydrogen storage tank 1. One end of the dispensing pipe 32 is connected to the outlet end of the pump 3, and the other end is connected to the inlet end of equipment that uses liquefied hydrogen LH as fuel or a transport truck.

[0020] In this embodiment, the pump 3 for dispensing the liquefied hydrogen LH inside the tank body 10 is located outside the inner tank 12. This is because maintenance work is easier than if the pump 3 were installed in the storage space 10A where the liquefied hydrogen LH is stored. In this case, space for installing the pump 3 is required on the side of the tank body 10. In this embodiment, the above-mentioned protrusion 23 is formed on the liquid barrier dyke 2, and a storage chamber 51 is provided inside it, thereby ensuring a place to install the pump 3.

[0021] The storage chamber 51 is disposed within the body of the ridge portion 23, and has a spatial volume large enough to accommodate the pump 3 and portions of the extraction pipe 31 and dispensing pipe 32. In this embodiment, the provision of the ridge portion 23 causes the outer peripheral surface 2A of the liquid barrier 2 to form a portion that bulges outward in the radial direction, creating space for the storage chamber 51. An outer wall portion 23A exists between the outer peripheral surface 2A and the storage chamber 51. An inner wall portion 23B (side portion of the liquid barrier) exists between the storage chamber 51 and the tank body 10. The inner wall portion 23B is part of the annular portion 22 and is the body of the portion where the ridge portion 23 exists.

[0022] An extraction opening 33 is provided in the inner wall portion 23B located radially inside the storage chamber 51, allowing the extraction pipe 31 to pass through into the storage chamber 51. The extraction opening 33 is a cylindrical hole that passes radially through the inner wall portion 23B, which is part of the liquid barrier dam 2. The extraction opening 33 is not limited to a cylindrical shape, and may be a hole with an elliptical, triangular, rectangular, or other cross-sectional shape. A gap exists between the inner surface of the extraction opening 33 and the outer peripheral surface of the extraction pipe 31. Note that the extraction pipe 31 and the outer tank side plate 11S are joined at the portion where they pass through.

[0023] The inner wall portion 23B has a take-out opening 33, which is a tunnel-shaped through-hole. In this embodiment, the inner wall portion 23B is the penetration portion 24 through which the take-out pipe 31 of the liquid barrier dyke 2 passes. The penetration portion 24 includes a reinforcing portion that reinforces its strength. This reinforcing portion will be described in detail below with reference to Figures 3 to 5.

[0024] The protrusion 23 further includes a passage 52 for workers to access the storage chamber 51. The passage 52 extends vertically within the protrusion 23. A lower end opening 53 is provided at the lower end of the passage 52, and an upper end opening 54 is provided at the upper end. The lower end opening 53 is an opening that communicates with the storage chamber 51. The upper end opening 54 opens to the top surface 23T of the protrusion 23. A ladder 55 is installed in the passage 52 to allow workers to move forward and backward. The upstream portion of the discharge pipe 32 is also disposed within the passage 52. A door 56 is provided at the upper end opening 54 to open and close the upper end opening 54. The door 56 is normally closed and is opened during maintenance work, etc. The installation of the door 56 prevents rainwater, dust, and the like from entering the storage chamber 51 and the passage 52, thereby keeping them clean.

[0025] The space of the storage chamber 51 and the passage 52 is isolated from the cold insulation layer 13, and therefore can be an air environment. Therefore, workers can easily access the pump 3 in the storage chamber 51 through the passage 52, which makes maintenance work easier. In order to improve explosion-proof properties, the space of the storage chamber 51 and the passage 52 may be filled with an inert gas such as nitrogen gas.

[0026] In the liquefied hydrogen storage tank 1 according to this embodiment, the inner space of the outer tank 11 and the space within the body of the protrusion 23 form a liquid storage space that can store liquid that leaks from the inner tank 12. The upper surface of the liquid storage space is sealed by the outer tank roof 11R and the opening / closing door 56. Therefore, even if a liquid leak occurs due to damage to the tank body 10 or the like, the leaked liquid is contained in the liquid storage space, and the outflow of vaporized liquefied hydrogen LH can be suppressed.

[0027] Furthermore, a storage chamber 51 is provided in the protruding portion 23 of the dike 2, and the storage chamber 51 accommodates a pump 3 that discharges liquefied hydrogen LH to the outside through the tank side plate. This makes maintenance easier than when the pump is installed inside the inner tank 12. When the pump 3 is installed inside the inner tank 12 of a liquefied hydrogen storage tank 1 that stores liquefied hydrogen LH, the pump 3, which is immersed in the liquefied hydrogen LH, must be removed to the outside, making it difficult to develop a maintenance method that is safe and easy to operate. In contrast, in this embodiment, the pump 3 is disposed in the storage chamber 51 outside the inner tank side plate 12S, so the work of removing the pump 3 from the inner tank 12 itself does not occur, making maintenance easier.

[0028] The liquefied hydrogen storage tank 1 of this embodiment has the advantages described above. However, because the dike 2 is provided with the penetration portion 24, which includes the extraction opening 33 through which the extraction pipe 31 passes, there is a concern that the penetration portion 24 may become a weak point in terms of strength. One case in which a weak point in strength becomes apparent is when liquefied hydrogen LH leaks from the inner tank 12. In this case, the liquid pressure of the leaked liquefied hydrogen LH acts on the dike 2 in a direction that expands the diameter of the dike 2. This liquid pressure causes tensile stress to act on the dike 2 in the circumferential direction. If an extraction opening 33 is provided in such a dike 2, the penetration portion 24, which includes the extraction opening 33, is more susceptible to stress concentration than other portions, making it a weak point.

[0029] Furthermore, the prestressing associated with the prestressed concrete structure of the dike 2 also makes the penetration portion 24 a weak point in terms of strength. As mentioned above, the dike 2 is formed with a prestressed concrete structure to ensure strength. If the dike 2, including the circular annular portion 22 surrounding the tank body 10, is formed with a prestressed concrete structure, as shown in FIG. 2 , a contraction force F acts on the concrete forming the dike 2, constricting the dike 2 circumferentially due to the compressive force of the prestressed concrete steel. If an access opening 33 is provided in the dike 2 to which the contraction force F is preliminarily applied, the penetration portion 24 including the access opening 33 is more susceptible to stress concentration than other portions, making it a weak portion as well. To resolve the above-mentioned weakness, a reinforcing portion is provided in this embodiment to reinforce the strength of the penetration portion 24. Specific examples of the reinforcing portion are described below.

[0030] 3 is a perspective view showing a first example of a reinforcement part 6 incorporated into the penetration part 24 of the dike 2. The reinforcement part 6 includes a pipe material 61 that covers the outlet pipe 31, and a stiffener 62 that covers the periphery of the pipe material 61. The reinforcement part 6 also includes connecting members 63, end ribs 64, and intermediate ribs 65 as load transfer members. The reinforcement part 6 further includes stud dowels 66 as anchoring members for the body of the penetration part 24.

[0031] The pipeline material 61 is a cylindrical pipe made of a metal pipe such as carbon steel, stainless steel, low-temperature steel, or aluminum alloy. The pipeline material 61 is not limited to a cylindrical shape, and may be a tubular body having an elliptical, rectangular, or other cross-sectional shape. The hollow portion of the pipeline material 61 ultimately becomes the outlet opening 33 through which the outlet pipe 31 passes. In other words, the pipeline material 61 serves as the lining of the through-hole for the outlet opening 33 drilled in the dike 2. To protect the body of the through-hole 24 from cold and heat in the event of a leak of liquefied hydrogen LH, it is desirable to attach a layer of insulating material to the outer or inner surface of the pipeline material 61. Examples of insulating material include foam materials such as rigid urethane foam and insulating concrete. Alternatively, or in addition to insulating material, the pipeline material 61 may be provided with a vacuum insulation layer. In this case, using a vacuum double-walled pipe as the pipeline material 61 allows for compactness and facilitates installation.

[0032] The stiffeners 62 are arranged to provide the pipe material 61 with resistance to the crushing force acting to crush the pipe material 61 radially inward due to the tensile stress during leakage described above and the contraction force F derived from the PC structure shown in FIG. 2 . FIG. 3 illustrates three stiffeners 62: a first stiffener 62A, a second stiffener 62B, and a third stiffener 62C, arranged at predetermined intervals in the pipe axial direction. The first stiffener 62A is a rectangular plate made of the same material as the pipe material 61 and has a through-hole in the center through which the pipe material 61 passes. The through-hole is fixed to the outer peripheral surface of the pipe material 61. This fixation is preferably achieved by welding, for example. The same applies to the second stiffener 62B and the third stiffener 62C. The shape of the stiffeners 62 is not limited as long as they extend in a direction perpendicular to the pipe axial direction of the pipe material 61, and they may be, for example, a circular plate. The number of stiffeners 62 is also arbitrary, and can be determined depending on the expected crushing force.

[0033] The connecting member 63 is a member that connects the three stiffeners 62A, 62B, and 62C in the pipe axis direction. The connecting member 63 is made of a flat steel plate extending in the pipe axis direction and is welded to each side edge of the stiffeners 62A, 62B, and 62C. The end rib 64 is a right-angled triangular steel rib that extends radially outward from the outer circumferential surface of the pipe material 61 near the end of the pipe material 61. One adjacent side of the end rib 64 is welded to the outer circumferential surface of the pipe material 61, and the other adjacent side is welded to the first stiffener 62A. The intermediate rib 65 is a rectangular steel rib that is arranged between the first stiffener 62A and the second stiffener 62B and between the second stiffener 62B and the third stiffener 62C. One long side of the intermediate rib 65 is welded to the outer peripheral surface of the pipe material 61 , and the other long side is welded to the inner surface of the connecting material 63 .

[0034] The stud dowels 66 are made of cylindrical steel and are welded to extend outward from each side of the stiffeners 62A, 62B, and 62C. The stud dowels 66 engage with the penetration portions 24 of the dike 2 to provide an anchoring effect. As long as they provide the anchoring effect, members other than the stud dowels 66 may be attached to the pipeline material 61, the stiffeners 62, or the connecting members 63. For example, short pieces of rebar may be welded to the pipeline material 61 or the stiffeners 62.

[0035] The reinforcement section 6 having the above structure allows the hole through which the extraction pipe 31 passes in the dike 2 to be partitioned by the pipe material 61, thereby ensuring a certain degree of strength for the penetration section 24. Furthermore, because the pipe material 61 is covered with the stiffeners 62, the rigidity of the pipe material 61, particularly its resistance to radial crushing loads, is enhanced. Furthermore, the crushing load applied to gaps in the axial direction of the pipe material 61 where no stiffeners 62 are present can be transmitted to the three stiffeners 62A, 62B, and 62C via the end ribs 64 or intermediate ribs 65 and the connecting members 63. This also enhances the rigidity of the gaps. Furthermore, the engagement between the stud dowels 66 and the prestressed concrete of the penetration section 24 prevents the pipe material 61 from slipping out in the axial direction.

[0036] It is desirable to adopt a prefabricated construction method in which the reinforcement 6 is preassembled in a factory or the like and then embedded in the location corresponding to the penetration 24 during construction of the dike 2. For example, a flat steel plate is cylindrically formed and butt-welded to produce the pipeline 61. Next, stiffeners 62 (62A, 62B, 62C) are fitted to the pipeline 61 and fillet-welded. The required number of end ribs 64 and intermediate ribs 65 are then welded to the pipeline 61 and stiffeners 62, and connecting members 63 are welded to the stiffeners 62. Finally, stud dowels 66 are welded to the appropriate locations on the stiffeners 62. In the embodiment of Figure 3, the stiffeners 62 themselves can provide anchoring effects, so the stud dowels 66 may be omitted. The prefabricated reinforcement 6 is then transported to the tank construction site, installed in the location where the penetration 24 is to be formed, and concrete is poured. The adoption of the above prefabricated construction method simplifies on-site construction work.

[0037] [Second Example of Reinforcement for Penetration Portion] Figure 4 is a perspective view showing a second example of a reinforcement portion 6A incorporated into the penetration portion 24 of the dike 2. The reinforcement portion 6A includes a pipe material 61 that covers the outlet pipe 31 and a structural steel stiffener 67 that surrounds the pipe material 61. The reinforcement portion 6A also includes a truss frame 671 and a structural steel connector 68 as load transfer members. The reinforcement portion 6A further includes a stud dowel 66 as an anchor member. The structural steel stiffener 67 corresponds to the stiffener 62 in the first example of Figure 3, and the structural steel connector 68 corresponds to the connector 63 in the first example.

[0038] The shaped steel stiffeners 67 are components that provide the pipe material 61 with resistance to the crushing force due to the compression force F derived from the PC structure. FIG. 4 illustrates three shaped steel stiffeners 67 arranged at predetermined intervals in the pipe axial direction: a first stiffening frame 67A (first stiffener), a second stiffening frame 67B (second stiffener), and a third stiffening frame 67C. The first stiffening frame 67A is formed by assembling steel materials in a rectangular shape, and a truss frame 671 is further assembled in a rectangular shape inside the first stiffening frame 67A. The pipe material 61 is passed through the frame of the truss frame 671 within the frame of the first stiffening frame 67A. The same applies to the second stiffening frame 67B and the third stiffening frame 67C.

[0039] The shaped steel connecting member 68 is a steel member extending in the pipe axial direction, and connects the three stiffening frames 67A, 67B, and 67C in the pipe axial direction. That is, the reinforcing portion 6A of the second example is a rectangular parallelepiped frame body in which three stiffening frames 67A, 67B, and 67C reinforced by truss frames 671 are connected by the shaped steel connecting member 68 and which accommodates the pipeline material 61. Stud dowels 66 are welded to the four side edges of the stiffening frames 67A, 67B, and 67C.

[0040] An end rib 672 and a steel plate 673 are welded near the end of the pipeline material 61. The end rib 672 is a right-angled triangular steel rib extending radially outward from the outer circumferential surface of the pipeline material 61. The steel plate 673 fills the gap between the rectangular frame formed by the truss frame 671 and the pipeline material 61, and is welded to the rectangular frame and the pipeline material 61. A steel rib may also be erected in the middle of the pipeline material 61 and welded to a shaped steel connector 68. As in the first example, in the reinforcing portion 6A, the stiffening frames 67A, 67B, and 67C provide resistance to crushing loads to the pipeline material 61, and the shaped steel connector 68 performs a load transmission function.

[0041] [Other Examples of Reinforcement Sections] Figures 5A and 5B are perspective views showing reinforcement sections 6B and 6C according to third and fourth examples. Reinforcement sections 6B and 6C have simpler structures than those of the first and second examples. The reinforcement section 6B shown in Figure 5A includes a pipe material 61A having a pipe thickness sufficient to withstand the contraction force F resulting from the PC structure. In other words, by increasing the pipe thickness of the pipe material 61A, the pipe material 61A itself has sufficient rigidity without the use of a stiffener. The hollow portion of the pipe material 61A serves as the outlet opening 33 through which the outlet piping 31 passes. A stud dowel 66 is provided on the outer circumferential surface of the pipe material 61A. If other means are used to prevent the pipe material 61A from slipping out, the stud dowel 66 may be omitted. For example, flange-shaped collars may be provided on both ends of the pipe material 61A to prevent the pipe material 61A from slipping out.

[0042] The reinforcing portion 6C shown in Fig. 5B includes a cast pipeline material 61B manufactured by casting. The cast pipeline material 61B has a hole 611 formed by inserting a core during manufacturing. This hole 611 becomes the extraction opening 33 through which the extraction piping 31 passes. Around the hole 611, there is a cast material with a thickness sufficient to withstand the contraction force F. A stud dowel 66 is provided on the outer peripheral surface of the cast pipeline material 61B.

[0043] [Summary of the Disclosure] The specific embodiments described above include disclosures having the following configurations.

[0044] A liquefied hydrogen storage tank according to a first aspect of the present disclosure comprises a tank body including an inner tank for storing liquefied hydrogen and an outer tank formed between the inner tank and the outer tank with an insulation layer interposed therebetween, a concrete liquid barrier erected so as to surround the outer periphery of the tank body, and piping that penetrates the tank body and the liquid barrier and is used to discharge the liquefied hydrogen stored in the inner tank to the outside, and the liquid barrier includes a reinforcing portion that reinforces the strength of the penetration portion through which the piping passes.

[0045] According to the first aspect, the reinforced portion is included in the penetration portion through which the liquefied hydrogen dispensing pipe passes, thereby improving the strength of the penetration portion, and therefore, even if stress concentration occurs in the penetration portion, deformation or the like in the penetration portion can be suppressed.

[0046] A liquefied hydrogen storage tank according to a second aspect is the liquefied hydrogen storage tank according to the first aspect, wherein the dike has a prestressed concrete structure.

[0047] The strength of the dike can be increased by constructing it with a prestressed concrete (PC) structure. In PC structures, pre-compressive stress is applied to the concrete using PC steel wires. When the dike surrounding the tank body is constructed with a PC structure, prestress is applied to squeeze the concrete in the circumferential direction. Therefore, if the dike has a penetration, stress concentration due to the prestress is likely to occur at the penetration. However, by providing the reinforcing portion at the penetration, stress concentration due to the prestress can be countered.

[0048] A liquefied hydrogen storage tank according to a third aspect is the liquefied hydrogen storage tank according to the first or second aspect, wherein the reinforcing portion includes a piping material that covers the piping, and a stiffening material that covers the periphery of the piping material.

[0049] According to the third aspect, the hole through which the piping passes in the dike can be defined by the pipe material, ensuring a certain degree of strength at the penetration part. Furthermore, since the pipe material is covered with a stiffening material, the rigidity of the pipe material, particularly its resistance to crushing forces in the pipe diameter direction, can be increased.

[0050] A liquefied hydrogen storage tank according to a fourth aspect is the liquefied hydrogen storage tank of the third aspect, wherein the stiffening members include a first stiffening member and a second stiffening member arranged at a predetermined interval in the axial direction of the pipeline material, and the reinforcing portion further includes a connecting member connecting the first stiffening member and the second stiffening member.

[0051] According to the fourth aspect, the first stiffener and the second stiffener are connected by a connecting member. Therefore, the load received by the pipeline material between the stiffeners can be transmitted to the first stiffener and the second stiffener through the connecting member. This further increases the strength of the penetration portion.

[0052] A liquefied hydrogen storage tank according to a fifth aspect is a liquefied hydrogen storage tank according to any one of the first to fourth aspects, wherein the reinforcing portion includes a pipe material covering the piping and an anchor material protruding from the outer peripheral surface of the pipe material.

[0053] According to the fifth aspect, the engagement between the anchor material and the concrete can prevent the pipeline material from slipping out in the axial direction of the pipe.

[0054] The liquefied hydrogen storage tank according to the sixth aspect is a liquefied hydrogen storage tank according to any one of the first to forty-fifth aspects, further comprising a pump that discharges liquefied hydrogen from the inner tank to the outside, wherein the dike has an internal storage chamber that houses the pump, and the penetration portion and the reinforcing portion are provided on the side of the dike between the storage chamber and the tank body.

[0055] According to the sixth aspect, the liquefied hydrogen stored in the inner tank can be discharged through piping by a pump disposed in the storage chamber inside the dike.

[0056] REFERENCE SIGNS LIST 1 Liquefied hydrogen storage tank 10 Tank body 11 Outer tank 12 Inner tank 13 Cold insulation layer 2 Liquid barrier 23 Protrusion 23B Inner wall (side of liquid barrier) 24 Penetration portion 3 Pump 31 Extraction piping (piping) 33 Extraction opening 51 Storage chamber 6, 6A, 6B, 6C Reinforcement portion 61 Pipe material 62 Stiffener 62A First stiffener 62B Second stiffener 63 Connection material 66 Stud dowel (anchor material) LH Liquefied hydrogen

Claims

1. A liquefied hydrogen storage tank comprising: a tank body including an inner tank for storing liquefied hydrogen, and an outer tank formed between the inner tank and the outer tank with an insulation layer between them; a concrete liquid retaining dike erected so as to surround the outer periphery of the tank body; and piping that penetrates the tank body and the liquid retaining dike and is used to discharge the liquefied hydrogen stored in the inner tank to the outside, wherein the liquid retaining dike includes a reinforcing section that reinforces the strength of the penetration section through which the piping passes.

2. A liquefied hydrogen storage tank as claimed in claim 1, wherein the liquid retaining wall has a prestressed concrete structure.

3. A liquefied hydrogen storage tank as claimed in claim 1 or 2, wherein the reinforcing portion includes a piping material that covers the piping, and a stiffening material that covers the periphery of the piping material.

4. A liquefied hydrogen storage tank as described in claim 3, wherein the stiffening members include a first stiffening member and a second stiffening member arranged at a predetermined interval in the axial direction of the pipeline material, and the reinforcing portion further includes a connecting member connecting the first stiffening member and the second stiffening member.

5. A liquefied hydrogen storage tank as claimed in claim 1 or 2, wherein the reinforcing portion includes a piping material covering the piping, and an anchor material protruding from the outer peripheral surface of the piping material.

6. A liquefied hydrogen storage tank as claimed in claim 1 or 2, further comprising a pump for discharging liquefied hydrogen within the inner tank to the outside, the liquid retaining wall having an internal storage chamber for accommodating the pump, and the penetration portion and the reinforcing portion being provided between the storage chamber and the tank body.

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