Liquefied hydrogen storage tank

Abstract

A liquefied hydrogen storage tank (1) is provided with: an inner tank (4) including an inner tank roof (43) and inner tank side plates (42); the middle groove (3) comprises a middle groove top (33) positioned above the inner groove top (43) and a middle groove side plate (32) positioned on the outer side of the inner groove side plate (42); an outer tank (2) that accommodates the intermediate tank (3) therein; a heat insulation space (S2) including a top space portion (S21) located between the inner groove top (43) and the middle groove top (33), and a side peripheral space portion (S22) located between the inner groove side plate (42) and the middle groove side plate (32); a heat insulating material (56) disposed in the heat insulating space (S2); the communicating pipe (45) penetrates through the inner tank top (43); and a gas passage provided in the top space section (S21) so as to allow gas to flow between the upper end opening (45a) of the communication pipe (45) and the side peripheral space section (S22).

Description

Technical Field

[0001] The invention relates to a liquefied hydrogen storage tank for storing liquefied hydrogen. Background Art

[0002] The multilayer shell tank described in Patent Document 1 below is already known. This multilayer shell tank is a flat-bottomed, three-layer shell tank for storing cryogenic liquefied gas. It comprises, from the inside, an inner tank, an intermediate tank, and an outer tank. The space between the inner and intermediate tanks, i.e., the inner insulating space (the first intertank space), and the space between the intermediate and outer tanks, i.e., the outer insulating space (the second intertank space), are each filled with an insulating material such as perlite. Furthermore, a connecting pipe is provided at the inner tank top, which constitutes the top of the inner tank.

[0003] In Patent Document 1, a connecting pipe extending through the inner tank top connects the space between the inner tank top and the intermediate tank top facing the inner tank top (top space) with the upper side of the inner tank (gas phase). However, in Patent Document 1, because the inner insulating space between the inner tank and the intermediate tank is filled with an insulating material such as perlite, the difference between the pressure acting on the upper side of the inner tank top and the pressure acting on the lower side of the inner tank top, i.e., the upper and lower pressure differential of the inner tank top, increases. This may cause stress to act on the inner tank top due to the upper and lower pressure differential.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-103917 Summary of the Invention

[0007] The present disclosure is made in view of the above situation, and its purpose is to provide a liquefied hydrogen storage tank that can reduce the upper and lower pressure differences of the inner tank top while achieving cold insulation of the inner tank.

[0008] In order to solve the above-mentioned problems, the liquefied hydrogen storage tank involved in one aspect of the present disclosure is a multi-layer shell tank for storing liquefied hydrogen, which includes: an inner tank, which includes an inner tank top and an inner tank side plate, and divides the storage space of the liquefied hydrogen; an intermediate tank, which includes an intermediate tank top located above the inner tank top, and an intermediate tank side plate located outside the inner tank side plate; an outer tank, which accommodates the intermediate tank inside; an insulating space, which includes a top space portion located between the inner tank top and the intermediate tank top, and a side space portion located between the inner tank side plate and the intermediate tank side plate; an insulating material, which is arranged in the insulating space; a connecting pipe, which passes through the inner tank top; and a gas channel, which is arranged in the top space portion in a manner that allows gas to flow between the upper end opening of the connecting pipe and the side space portion.

[0009] According to the liquefied hydrogen storage tank disclosed herein, the upper and lower pressure differences of the inner tank top can be reduced while achieving cold preservation of the inner tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a cross-sectional view showing the structure of a liquefied hydrogen tank according to the first embodiment of the present disclosure.

[0011] Figure 2 It is an enlarged cross-sectional view for explaining the flow of hydrogen gas in the head space.

[0012] Figure 3 It is a cross-sectional view for explaining a modified example of the first embodiment.

[0013] Figure 4 It is a cross-sectional view showing the structure of a liquefied hydrogen tank according to a second embodiment of the present disclosure.

[0014] Figure 5 It is a cross-sectional view showing the structure of a liquefied hydrogen tank according to a third embodiment of the present disclosure.

[0015] Figure 6 It is a perspective view for explaining a modified example of the third embodiment. DETAILED DESCRIPTION

[0016] (1) First embodiment

[0017] [Overall structure of liquefied hydrogen storage tank]

[0018] Figure 1 This is a cross-sectional view showing the structure of a liquefied hydrogen storage tank 1 according to a first embodiment of the present disclosure. The liquefied hydrogen storage tank 1 shown in this figure is a three-layer shell tank for storing liquefied hydrogen LH. It includes a tank base 10, an outer tank 2 erected on the tank base 10, an intermediate tank 3 housed within the outer tank 2, and an inner tank 4 housed within the intermediate tank 3. The outer tank 2, intermediate tank 3, and inner tank 4 are all circular in plan view and are arranged concentrically.

[0019] The tank foundation 10 is a concrete layer constituting the base portion of the liquefied hydrogen storage tank 1. The tank foundation 10 has a size larger than the outer diameter of the outer tank 2.

[0020] The outer tank 2 is a closed body made of a metal such as carbon steel. It includes an outer tank bottom plate 21, outer tank side plates 22, and an outer tank roof 23. The outer tank bottom plate 21 is a circular plate installed directly above the tank foundation 10. The outer tank side plates 22 are cylindrical side plates installed upright around the outer tank bottom plate 21. The outer tank roof 23 is a dome-shaped roof mounted on the upper end of the outer tank side plates 22 to cover the upper opening of the outer tank side plates 22. It is formed into a spherical shape that bulges upward.

[0021] The intermediate tank 3 is a closed body made of low-temperature steel such as SUS and is located within the outer tank 2. The intermediate tank 3 comprises an intermediate tank bottom plate 31, intermediate tank side plates 32, and an intermediate tank top plate 33. The intermediate tank bottom plate 31 is a circular plate with a smaller diameter than the outer tank bottom plate 21. The intermediate tank side plates 32 are cylindrical side plates erected around the periphery of the intermediate tank bottom plate 31. The intermediate tank top plate 33 is a dome-shaped roof mounted on the upper end of the intermediate tank side plates 32 to cover the upper opening of the intermediate tank side plates 32. It has an upwardly convex spherical surface.

[0022] The inner tank 4 is a tank that divides the storage space for liquefied hydrogen LH. The inner tank 4 is made of low-temperature steel such as SUS and is arranged inside the intermediate tank 3. The inner tank 4 includes an inner tank bottom plate 41, an inner tank side plate 42, and an inner tank top 43. The inner tank bottom plate 41 is a circular plate with a smaller diameter than the intermediate tank bottom plate 31. The inner tank side plate 42 is a cylindrical side plate that is vertically arranged on the periphery of the inner tank bottom plate 41. The inner tank top 43 is a dome-shaped top that is installed on the upper end of the inner tank side plate 42 in a manner to cover the upper opening of the inner tank side plate 42, and is formed into a spherical shape that bulges upward.

[0023] A gas phase space S3 is formed in the upper inner portion of the inner tank 4. The gas phase space S3 is a space filled with hydrogen gas evaporated from the liquefied hydrogen LH and is formed between the inner tank ceiling 43 and the liquid level of the liquefied hydrogen LH.

[0024] A first-level concrete layer 24, a first ring portion 25, and a first bottom insulation layer 26 are interposed between the outer tank floor 21 and the intermediate tank floor 31. The first-level concrete layer 24 is a leveled concrete layer on the outer tank floor 21. The first ring portion 25 is a high-strength, annular concrete layer disposed around the periphery of the first-level concrete layer 24. The first bottom insulation layer 26 is a thermally insulating layer disposed on the inside of the first ring portion 25 and on the first-level concrete layer 24.

[0025] A second level concrete layer 34, a second ring portion 35, and a second bottom insulation layer 36 are interposed between the middle tank floor 31 and the inner tank floor 41. The second level concrete layer 34 is constructed on the middle tank floor 31. The second ring portion 35 is a high-strength, annular concrete layer disposed around the periphery of the second level concrete layer 34. The second bottom insulation layer 36 is a thermally insulating layer disposed on the inside of the second ring portion 35 and on the second level concrete layer 34.

[0026] A gap of a predetermined width is formed between the inner tank 4 and the intermediate tank 3, and between the intermediate tank 3 and the outer tank 2. Each gap functions as an insulating space that suppresses heat transfer from the outside air to the liquefied hydrogen LH. Hereinafter, the gap between the outer tank 2 and the intermediate tank 3 is referred to as the outer insulating space S1, and the gap between the inner tank 4 and the intermediate tank 3 is referred to as the inner insulating space S2. The inner insulating space S2 corresponds to the "insulating space" in this disclosure.

[0027] The outer insulating space S1 between the outer tank 2 and the intermediate tank 3 is filled with an inert gas, such as nitrogen, having a higher boiling point than hydrogen. Furthermore, granular insulating material 55 is disposed in the outer insulating space S1. Granular insulating material 55 is a flowable insulating material composed of granular materials such as perlite and / or glass bubbles.

[0028] The inner insulating space S2 between the inner tank 4 and the intermediate tank 3 is filled with hydrogen. Furthermore, granular insulating material 56 and glass wool 57 are arranged in the inner insulating space S2. Granular insulating material 56 is a granular insulating material made of perlite and / or glass foam, similar to the granular insulating material 55 in the outer insulating space S1 described above. Glass wool 57 is a cotton-like insulating material primarily composed of glass fibers.

[0029] The inner insulation space S2 includes a top space portion S21 and a side space portion S22. The top space portion S21 is a dome-shaped space formed between the inner tank top 43 and the middle tank top 33, and the side space portion S22 is a cylindrical space formed between the inner tank side plate 42 and the middle tank side plate 32. The granular insulation material 56 is arranged in both the top space portion S21 and the side space portion S22, and the glass wool 57 is mainly arranged in the side space portion S22. Specifically, the glass wool 57 is arranged along the outer surface of the inner tank side plate 42 in a manner that occupies the inner area of ​​the side space portion S22. The granular insulation material 56 is arranged in the inner insulation space S2 except for the arrangement area of ​​the glass wool 57 and the lower space (gas channel R1) of the partition wall 71 described later.

[0030] A connecting pipe 45 is installed in the inner tank top 43. This connecting pipe 45 connects the inner insulating space S2 with the gas phase space S3 within the inner tank 4 and is positioned to penetrate the center of the inner tank top 43 along its thickness. The connecting pipe 45 has an upper opening 45a that opens into the inner insulating space S2 and a lower opening 45b that opens into the gas phase space S3. One or more connecting pipes 45 can be installed in appropriate locations within the inner tank top 43, including its center. However, in this embodiment, a single connecting pipe 45 is installed in the center of the inner tank top 43.

[0031] [Deck and gas channel]

[0032] The top space S21 is provided with a partition 7 that partitions the top space S21 vertically. The partition 7 is a structure for defining the arrangement area of ​​the granular insulating material 56 and is provided along the upper side of the inner tank top 43 .

[0033] Specifically, the partition 7 includes a dome-shaped curved partition wall 71 that covers the upper side of the inner tank top 43, and a plurality of supports 72 that support the partition wall 71 on the inner tank top 43. The partition wall 71 is spaced apart from both the inner tank top 43 and the intermediate tank top 33, thereby dividing the top space S21 into two spaces, one above the other. The supports 72 are dispersed in the radial and circumferential directions.

[0034] The partition wall 71 covers substantially the entire upper side of the inner tank top 43. The partition wall 71 is formed of a material that does not allow the granular heat insulating material 56 to pass through. Preferably, the partition wall 71 has air permeability that does not allow the granular heat insulating material 56 to pass through but allows gas to flow through.

[0035] Distributed supports 72 support the partition wall 71 on the inner groove top 43. This creates a gas passage R1 beneath the partition wall 71, that is, between the partition wall 71 and the inner groove top 43. This passage R1 has open spaces at both ends, allowing gas to flow. The passage R1 is continuous in the radial direction, extending from the center to near the outer edge of the inner groove top 43. In other words, the passage R1 is formed in the lower region of the top space S21 that is adjacent to the inner groove top 43.

[0036] To ensure smooth gas flow through the aforementioned gas passage R1, the granular thermal insulation material 56 is not disposed in the gas passage R1. Specifically, the granular thermal insulation material 56 is confined to the upper side of the partition wall 71 in the top space portion S21. Furthermore, the granular thermal insulation material 56 is confined to the outer side of the glass wool 57 in the side peripheral space portion S22. In other words, the granular thermal insulation material 56 is confined to the outer area of ​​the inner insulating space S2, occupying the space above the partition wall 71 and the space outside the glass wool 57, respectively.

[0037] An annular opening is formed at the radially outer end of gas passage R1, that is, between the outer edge of partition wall 71 and the outer edge of inner tank top 43. This annular opening is covered with glass wool 57. Specifically, the glass wool 57 is arranged cylindrically to cover the entire outer surface of inner tank side plate 42, with the upper end 57a of the glass wool 57 covering the radially outer end of gas passage R1. The upper end 57a of the glass wool 57, thus covering the radially outer end of gas passage R1, acts as a shield to prevent the granular insulation material 56 from flowing into gas passage R1.

[0038] A clamp 74 ( Figure 2 The clamp 74 is a flexible strip made of glass fiber cloth or the like, and is arranged to extend radially from the outer edge 71a of the partition wall 71 to the upper end 57a of the glass wool 57. The inner portion of the clamp 74 is fixed to the outer edge 71a of the partition wall 71 by bonding or the like, and the outer portion of the clamp 74 is fixed to the upper end 57a of the glass wool 57 by anchor pins or the like. As a result, the upper end 57a of the glass wool 57 is fixed in a position covering the radially outer end of the gas passage R1.

[0039] The upper end opening 45a of the connecting pipe 45 opens at the center of the gas passage R1. Thus, the gas passage R1 extending from the center to the outer edge of the inner tank top 43 and the gas phase space S3 below the inner tank top 43 are connected to each other through the connecting pipe 45. In this way, gas flow between the gas phase space S3 and the side peripheral space S22 can be achieved. For example, Figure 2 As shown by the arrow, hydrogen gas flowing from the gas phase space S3 through the connecting tube 45 into the top space S21 can flow through the gas passage R1 from the upper end opening 45a of the connecting tube 45 to the outer edge of the top space S21, that is, to the side peripheral space S22. In other words, the gas passage R1 is provided in the top space S21 to allow gas to flow between the upper end opening 45a of the connecting tube 45 and the side peripheral space S22.

[0040] [Effects]

[0041] As described above, in this embodiment, granular insulation material 56 is placed in the inner insulating space S2 between the inner tank 4 and the intermediate tank 3. Furthermore, a connecting pipe 45 is provided at the inner tank ceiling 43, connecting the top space S21 of the inner insulating space S2 with the gas phase space S3 within the inner tank 4. Furthermore, a radially extending gas passage R1 is formed in the top space S21 to allow gas flow between the upper end opening 45a of the connecting pipe 45 and the lateral space S22. This structure offers the advantage of reducing the pressure differential between the upper and lower portions of the inner tank ceiling 43 while maintaining the inner tank 4's coolness.

[0042] That is, in this embodiment, since a granular insulating material 56 is arranged in the inner insulating space S2 between the inner tank 4 and the middle tank 3, the heat input to the inner tank 4 from the outside can be suppressed based on the insulating effect achieved by the granular insulating material 56, thereby keeping the inner tank 4 at a low temperature.

[0043] Furthermore, since the connecting pipe 45 penetrates the inner tank top 43 and a gas passage R1 is formed in the top space S21 between the inner tank top 43 and the intermediate tank top 33, when the pressure of the hydrogen gas in the gas phase space S3 in the inner tank 4 increases, the hydrogen gas can be introduced into the top space S21 through the connecting pipe 45, and the introduced hydrogen gas can flow through the gas passage R1 to the outer edge of the top space S21 or the side peripheral space S22 (see FIG. Figure 2 Conversely, when the pressure in the gas phase space S3 decreases, a reverse hydrogen flow from the top space S21 to the gas phase space S3 can be formed. This can reduce the difference between the pressure acting on the upper side of the inner tank top 43 and the pressure acting on the lower side of the inner tank top 43, i.e., the upper and lower pressure differential, over a large radial range, thereby alleviating the stress caused by this pressure differential on the inner tank top 43.

[0044] For example, if granular insulation 56 is disposed throughout the entire top space S21, thereby blocking the gas passage R1, the flow of hydrogen gas between the upper end opening 45a of the connecting tube 45 and the lateral space S22 would be obstructed by the granular insulation 56. As a result, the vertical pressure differential across the inner tank top 43 would tend to increase, particularly in the radially outer region. In contrast, according to this embodiment, the gas passage R1 is formed to allow gas flow between the upper end opening 45a of the connecting tube 45 and the lateral space S22. This can suppress the increase in the vertical pressure differential across the tank top 43 caused by this situation, thereby reducing the stress acting on the inner tank top 43.

[0045] Specifically, in this embodiment, a partition 7 including a partition wall 71 that separates the top space S21 from top to bottom is constructed on the inner tank top 43. A gas passage R1 is formed below the partition wall 71, and granular thermal insulation material 56 is disposed above the partition wall 71. This configuration reduces the pressure differential between the top and bottom of the inner tank top 43 by utilizing the gas passage R1 below the partition wall 71, and allows the granular thermal insulation material 56 to be stably disposed above the partition wall 71. Furthermore, since the gas phase space S3 within the inner tank 4 communicates with the gas passage R1 located above the gas phase space S3 across the inner tank top 43, the pressure differential between the top and bottom of the inner tank top 43 can be effectively reduced, thereby alleviating stress on the inner tank top 43.

[0046] Furthermore, in this embodiment, glass wool 57 is arranged along the inner tank side plate 42, and the radially outer end of the gas passage R1 is sealed by the upper end portion 57a ​​of the glass wool 57. This configuration prevents the granular insulation 56 from flowing into the gas passage R1. Therefore, the granular insulation 56 does not hinder pressure equalization within the gas passage R1, effectively reducing the pressure difference between the upper and lower sides of the inner tank top 43. Furthermore, the combination of the granular insulation 56 and the glass wool 57 ensures that the inner tank side plate 42 is adequately insulated.

[0047] [Modification]

[0048] In the first embodiment, the gas passage R1 is formed below the partition wall 71 supported on the inner tank top 43 via the support member 72 . However, the partition wall defining the upper side of the gas passage does not necessarily need to be supported on the inner tank top 43 . Figure 3 An example of changing the supporting structure of the partition wall is shown. Figure 3 In the modified example shown, a dome-shaped structure including a partition wall 81 and a plurality of hangers 82 is constructed in the top space portion S21. The partition wall 81 is configured so as to partition the top space portion S21 from top to bottom by being fixed to the lower ends of the plurality of hangers 82 extending from the middle tank top 33. In other words, the partition wall 81 is configured in a position spaced apart from both the inner tank top 43 and the middle tank top 33 by being supported by the lower side of the middle tank top 33 in a suspended state. Granular insulation material 56 is disposed on the upper side of the partition wall 81, and a gas passage R11 is formed on the lower side of the partition wall 81. As in the first embodiment, in order to enable smooth gas flow through the gas passage R11, granular insulation material 56 is not disposed in the gas passage R11.

[0049] In the first embodiment, glass wool 57, a cotton-like thermal insulation material, is disposed along the inner tank side plates 42. However, the glass wool 57 can be omitted. Specifically, the granular thermal insulation material 56 can be used as the entire thermal insulation material disposed within the inner insulating space S2. In this case, it is preferable to provide an air-permeable fence (e.g., made of glass fiber cloth) at the radially outer end of the gas passage R1 as a shield to prevent the granular thermal insulation material 56 from flowing into the gas passage R1.

[0050] In the first embodiment, no insulating material is specifically arranged in the gas passage R1. However, various insulating materials (such as cotton-like insulating materials such as glass wool 57) that allow gas to pass through more easily may be arranged in the entire or part of the gas passage R1.

[0051] (2) Second embodiment

[0052] Figure 41 is a cross-sectional view showing a liquefied hydrogen tank 1A according to a second embodiment of the present disclosure. The liquefied hydrogen tank 1A according to the second embodiment is the same as the liquefied hydrogen tank 1 according to the first embodiment except that the structure of the heat insulating material and the gas passage in the inner heat insulating space S2 is different. Figure 4 In the embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted. Hereinafter, the differences from the first embodiment will be mainly described.

[0053] like Figure 4 As shown, in the second embodiment, two types of insulation materials, a fixed-shape heat insulation material 101 and a granular heat insulation material 102, are used as insulation materials arranged in the inner insulation space S2. The granular heat insulation material 102 is a granular heat insulation material made of perlite and / or glass bubbles, etc., similar to the granular heat insulation material 56 used in the first embodiment described above. The fixed-shape heat insulation material 101 is a non-flowing heat insulation material having shape-retaining properties. As the fixed-shape heat insulation material 101, a solid heat insulation material made of polyurethane, etc., can be suitably used. In addition, as the fixed-shape heat insulation material 101, a cotton-shaped or mat-shaped heat insulation material made of glass wool, etc. can also be used; or a material obtained by bagging granular heat insulation materials such as perlite and / or glass bubbles (tiny hollow glass balls).

[0054] The shaped thermal insulation material 101 is applied to cover the lower side of the intermediate tank top 33. Specifically, the shaped thermal insulation material 101 includes a plurality of thermal insulation material units 101a attached to the lower side of the intermediate tank top 33. The plurality of thermal insulation material units 101a are arranged adjacent to each other and secured to the intermediate tank top 33 using appropriate securing means. As a result, the substantially entire lower side of the intermediate tank top 33 is covered with the shaped thermal insulation material 101.

[0055] The height of the shaped thermal insulation material 101 is set to be shorter than the distance from the inner groove top 43 to the middle groove top 33. Thus, a predetermined gap can be formed between the lower side of the shaped thermal insulation material 101 and the inner groove top 43.

[0056] The granular thermal insulation material 102 is primarily located in the side peripheral space S22 and is not located in most of the top space S21. The height of the upper side of the granular thermal insulation material 102 is set higher than the lower end of the peripheral edge of the shaped thermal insulation material 101. As a result, the peripheral edge of the shaped thermal insulation material 101 and the upper end of the granular thermal insulation material 102 are arranged so as to overlap with each other.

[0057] By arranging the shaped insulating material 101 and the granular insulating material 102 in the above manner, a gas passage R12 is formed in the top space S21, extending from the center to the outer edge of the inner tank top 43. The existence of the gas passage R12 allows hydrogen gas to flow between the upper end opening 45a of the connecting pipe 45 and the side peripheral space S22 (the outer edge of the top space S21).

[0058] A fence 105 is disposed midway in the radial direction of the gas passage R12. The fence 105 is an annular partition that radially divides the gas passage R12 and is disposed so as to surround the communication tube 45 from the outside. The fence 105 is air-permeable, preventing the granular insulation material 102 from passing through but allowing gas to flow through. The fence 105 is made of a material such as glass fiber cloth, for example.

[0059] As described above, in the second embodiment, since the gas passage R12 is formed below the shaped thermal insulation material 101 disposed along the lower side of the intermediate tank top 33, the shaped thermal insulation material 101 can be used to cool the inner tank 4 and can also be used as a wall member defining the gas passage R12. Furthermore, the flow of hydrogen gas through the gas passage R12 reduces the pressure differential between the upper and lower portions of the inner tank top 43, thereby alleviating the stress exerted on the inner tank top 43 by this pressure differential.

[0060] In addition, in the second embodiment, since the fence 105 surrounding the connecting pipe 45 is arranged in the middle of the gas channel R12, the fence 105 can prevent the granular insulating material 102 existing in the lateral space portion S22 from moving radially inward toward the upper end opening 45a of the connecting pipe 45, thereby preventing the granular insulating material 102 from mixing into the inner tank 4 through the connecting pipe 45.

[0061] (3) Third embodiment

[0062] Figure 5 1 is a cross-sectional view showing a liquefied hydrogen tank 1B according to a third embodiment of the present disclosure. In this figure, the same components as those in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted.

[0063] like Figure 5 As shown, in the third embodiment, most of the inner insulation space S2 is filled with granular insulation 202. The granular insulation 202 is a granular insulation material made of perlite and / or glass bubbles, etc., similar to the granular insulation 56 used in the first embodiment.

[0064] A fence 205 is disposed near the connecting tube 45 in the headspace S21. The fence 205 is an annular partition that radially divides the headspace S21 and is disposed so as to surround the connecting tube 45 from the outside. The fence 205 is air-permeable, preventing the granular insulation material 202 from passing through but allowing gas to flow through. The fence 205 is made of a material such as glass fiber cloth, for example.

[0065] The granular insulation material 202 is arranged to occupy most of the inner insulation space S2 except the inner area of ​​the fence 205. In other words, the granular insulation material 202 is arranged to occupy the outer area of ​​the fence 205 in the top space S21 and the side peripheral space S22.

[0066] A shaped insulation material 201 is disposed within the inner region of the fence 205 in the top space S21. The shaped insulation material 201 is a non-flowable insulation material (e.g., a solid insulation material made of polyurethane) with shape retention, similar to the shaped insulation material 101 used in the second embodiment described above, and includes a plurality of insulation material units 201a mounted on the lower side of the intermediate tank top 33.

[0067] A plurality of hollow members 210 are disposed in the top space S21, extending radially outward from its center. Each hollow member 210 is formed so as to extend from a position near the connecting tube 45 to the lateral space S22. The inner ends of the hollow members 210, located near the connecting tube 45, are disposed inside a region of the fence 205 where the granular insulation material 202 is not disposed. The hollow members 210 extend radially from the inner region of the fence 205 through the fence 205 toward the lateral space S22.

[0068] The cavity within the hollow member 210 functions as a gas passage R13 for gas circulation. For example, hydrogen gas flowing from the gas phase space S3 into the top space portion S21 via the connecting pipe 45 can flow from the upper end opening 45a of the connecting pipe 45 (the inner area of ​​the fence 205) to the side peripheral space portion S22 via the gas passage R13. In other words, in the third embodiment, the cavity within the hollow member 210 constitutes a gas passage R13 that allows gas to circulate between the upper end opening 45a of the connecting pipe 45 and the side peripheral space portion S22. Although not shown in the figure, a breathable cover is installed at at least the radially outer end of the hollow member 210 to prevent the granular insulation material 202 from flowing into the gas passage R13 but to allow gas to circulate.

[0069] The shape of the hollow member 210 (gas passage R13) can be any shape as long as it extends from the center to near the outer edge along the inner groove top 43. The specific shape can be set accordingly. For example, the hollow member 210 can be a hollow fan-shaped member whose circumferential width increases toward the radially outer side, or it can be a pipe member with a constant diameter.

[0070] According to the above-mentioned third embodiment, since hydrogen is allowed to flow through the gas channel R13 in the hollow member 210 between the upper end opening 45a of the connecting pipe 45 and the side peripheral space portion S22, the upper and lower pressure differences of the inner groove top 43 can be reduced, thereby reducing the stress acting on the inner groove top 43.

[0071] In the third embodiment, the cavity in the hollow member 210 extending in the radial direction is formed as the gas passage R13, but the inner groove top 43 may constitute a part of the wall of the gas passage. Figure 6 As shown, by mounting the corrugated plate 301 having a wave-shaped cross section on the inner tank top 43 , a space sandwiched between the corrugated plate 301 and the inner tank top 43 can be formed as a gas passage.

[0072] [Summarize]

[0073] The above-mentioned embodiments and their variations include the following technical solutions.

[0074] The liquefied hydrogen storage tank involved in the first technical solution of the present disclosure is a multi-layer shell tank for storing liquefied hydrogen, which includes: an inner tank, which includes an inner tank top and an inner tank side plate, and divides the storage space of the liquefied hydrogen; an intermediate tank, which includes an intermediate tank top located above the inner tank top, and an intermediate tank side plate located outside the inner tank side plate; an outer tank, which accommodates the intermediate tank inside; an insulating space, which includes a top space portion located between the inner tank top and the intermediate tank top, and a side space portion located between the inner tank side plate and the intermediate tank side plate; an insulating material, which is arranged in the insulating space; a connecting pipe, which passes through the inner tank top; and a gas channel, which is arranged in the top space portion in a manner that allows gas to flow between the upper end opening of the connecting pipe and the side space portion.

[0075] According to the first aspect, since the insulating material is disposed in the insulating space between the inner tank and the intermediate tank, the insulating effect of the insulating material can suppress heat input from the outside into the inner tank, thereby keeping the inner tank at a low temperature.

[0076] In addition, since the connecting pipe runs through the inner tank top and a gas channel is formed in the top space between the inner tank top and the middle tank top, when the pressure of the hydrogen in the upper gas phase space in the inner tank becomes high, the hydrogen can be introduced into the top space through the connecting pipe, and the introduced hydrogen can flow to the outer edge or side space of the top space through the gas channel. On the contrary, when the pressure in the gas phase space becomes low, a reverse hydrogen flow from the top space to the gas phase space can be formed. Thus, the difference between the pressure acting on the upper side of the inner tank top and the pressure acting on the lower side of the inner tank top, i.e., the upper and lower pressure difference, can be reduced in a large range in the radial direction, and the stress caused to the inner tank top by the pressure difference can be reduced.

[0077] A liquefied hydrogen tank according to a second technical solution is as follows: in the first technical solution, the gas passage is formed in a lower region of the top space portion that is in contact with the inner tank ceiling.

[0078] According to the second technical solution, since the gas phase space in the inner tank and the gas channel located on the upper side of the gas phase space across the inner tank top are connected to each other, the upper and lower pressure differences of the inner tank top can be effectively reduced, thereby reducing the stress acting on the inner tank top.

[0079] A liquefied hydrogen storage tank according to a third technical solution is as follows: in the second technical solution, the gas passage is formed below a partition wall that partitions the head space portion up and down, and the thermal insulation material includes a granular thermal insulation material arranged above the partition wall.

[0080] According to the third aspect, the gas passage formed on the lower side of the partition wall can reduce the upper and lower pressure differences of the inner tank top, and the granular heat insulating material can be stably arranged on the upper side of the partition wall.

[0081] The liquefied hydrogen storage tank involved in the fourth technical solution is as follows: in the first to third technical solutions, the insulating material includes a granular insulating material arranged in the side peripheral space portion, and a shielding body is provided at the radial outer end of the gas channel to prevent the granular insulating material from flowing into the gas channel.

[0082] According to the fourth technical solution, the shielding body prevents the granular insulation material from flowing into the gas passage. Therefore, the granular insulation material does not hinder the pressure equalization in the gas passage, and the upper and lower pressure differences at the inner tank top can be effectively reduced.

[0083] The liquefied hydrogen storage tank involved in the fifth technical solution is as follows: in the first technical solution, the insulating material includes a fixed-shaped insulating material arranged along the lower side surface of the intermediate tank top, and the gas channel is formed on the lower side of the fixed-shaped insulating material.

[0084] According to the fifth aspect, the inner tank can be kept cool by the fixed-shape heat insulating material, and the fixed-shape heat insulating material can be used as a wall member for defining the gas passage.

[0085] Explanation of symbols

[0086] 1 liquefied hydrogen storage tank

[0087] 2 outer grooves

[0088] 3 Middle slot

[0089] 4 inner grooves

[0090] 32 Middle slot side panel

[0091] 33 Middle tank top

[0092] 42 inner tank side panel

[0093] 43 inner groove top

[0094] 45 connecting pipe

[0095] 45a (Connecting pipe) upper end opening

[0096] 56 Granular insulation material

[0097] 57 Glass wool (shielding body)

[0098] 71, 81 next door

[0099] 101 Shaped insulation material

[0100] S2 Inner insulation space (insulation space)

[0101] S21 Top space

[0102] S22 Side space

[0103] R1, R11, R12, R13 gas channels

Claims

1. A liquefied hydrogen storage tank is a multi-layer shell liquefied hydrogen storage tank for storing liquefied hydrogen, characterized in that include: The inner tank includes an inner tank top and inner tank side panels, and divides the storage space of liquefied hydrogen; an intermediate tank, comprising an intermediate tank top located above the inner tank top and an intermediate tank side plate located outside the inner tank side plate; an outer tank, accommodating the middle tank inside; The heat-insulating space comprises a top space portion located between the inner trough top and the middle trough top, and a side peripheral space portion located between the inner trough side plate and the middle trough side plate; a heat-insulating material disposed in the heat-insulating space; A connecting pipe passing through the top of the inner tank; as well as, A gas passage is provided in the top space portion so as to allow gas to flow between the upper end opening of the communication pipe and the side peripheral space portion.

2. The liquefied hydrogen storage tank according to claim 1, characterized in that: The gas passage is formed in a lower region of the top space portion that is in contact with the inner tank top.

3. The liquefied hydrogen storage tank according to claim 2, characterized in that: The gas passage is formed on the lower side of the partition wall that separates the top space portion from top to bottom. The thermal insulation material includes a granular thermal insulation material disposed on an upper side of the partition wall.

4. The liquefied hydrogen storage tank according to claim 1 or 2, characterized in that: The thermal insulation material includes a granular thermal insulation material arranged in the side peripheral space portion. A shield is provided at a radially outer end of the gas passage to prevent the granular thermal insulation material from flowing into the gas passage.

5. The liquefied hydrogen storage tank according to claim 1, characterized in that: The thermal insulation material includes a shaped thermal insulation material arranged along the lower side of the middle tank top, The gas passage is formed on the lower side of the shaped thermal insulation material.

Images