Heat insulation support structure

Abstract

To provide a heat insulation support structure capable of ensuring ease of manufacture and ease of construction on a large storage tank.SOLUTION: An heat insulation support structure 11 comprises a plurality of heat insulation support units 21 composed of: radiant heat reflection plate pieces 22 divided into a predetermined shape; and a plurality of hollow cylindrical bodies 13 arranged in an in-plane direction of the radiant heat reflection plate pieces 22 and having openings at both axial ends. Each of the plurality of hollow cylindrical bodies 13 is placed on the radiant heat reflection plate piece 22 so that at least one of openings at both axial ends is blocked, and the plurality of heat insulation support units 21, 21 are integrated together by joining the radiant heat reflection plate pieces 22, 22 together.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an insulating support structure for a storage tank. [Background technology]

[0002] In recent years, there has been an increasing demand for storage tanks that store liquid hydrogen. Liquid hydrogen is hydrogen gas that has been liquefied. Hydrogen gas does not emit carbon dioxide when burned, so it is expected to be used for power generation and other purposes as an environmentally friendly energy source. For industrial use of hydrogen gas, a large storage capacity (e.g., tens of thousands of m) is required. 3 It is thought that large storage tanks (above 100m2) will be required. In addition, the boiling point of hydrogen gas is extremely low at -253°C. For this reason, storage tanks for storing liquid hydrogen will need to have higher insulation performance than storage tanks for storing liquefied natural gas (LNG), etc.

[0003] Patent Document 1 discloses a double-shell cylindrical liquid hydrogen tank as an example of technology related to a storage tank for storing liquid hydrogen. This conventional tank has a double-shell structure consisting of an inner tank and an outer tank. A bottom support structure is provided between the bottom plate of the inner tank and the bottom plate of the outer tank. The bottom support structure includes a lower array body and an upper array body in which a plurality of cylindrical bodies are arranged in row and column directions, and bottom plates disposed above and below these array bodies. In the lower array body and the upper array body, the center positions of the cylindrical bodies are offset from each other in the row or column direction. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-143758 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, storage tanks for storing liquid hydrogen need to be large in size in order to ensure storage capacity. For this reason, the heat-insulating support structures applied to storage tanks are required to have not only insulation properties, toughness at room temperature, and viscoelasticity at low temperatures, but also ease of manufacture and ease of installation on large storage tanks.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide an insulating support structure that can ensure ease of manufacture and installation on large storage tanks. [Means for solving the problem]

[0007] The gist of this disclosure is as follows [1] to

[12] .

[0008] [1] In a storage tank having an inner tank and an outer tank, a thermal insulation support structure that supports the inner tank between the bottom plate of the inner tank and the bottom plate of the outer tank, the thermal insulation support structure comprising a plurality of thermal insulation support units each consisting of a radiant heat reflecting plate piece divided into a predetermined shape and a plurality of hollow cylindrical bodies arranged in the in-plane direction of the radiant heat reflecting plate piece and having openings at both axial ends, wherein each of the plurality of hollow cylindrical bodies is placed on the radiant heat reflecting plate piece so that at least one of the openings at both axial ends is blocked, and the plurality of thermal insulation support units are integrated together by joining the radiant heat reflecting plate pieces together.

[0009] In this heat-insulating support structure, each of the plurality of hollow cylindrical bodies is placed on the radiant heat reflecting plate piece so that at least one of the openings at both ends in the axial direction is blocked. By configuring the plurality of hollow cylindrical bodies to block the openings of the cylindrical bodies with a common radiant heat reflecting plate piece, it is possible to increase the ease of manufacture compared to a configuration in which a radiant heat reflecting plate is arranged inside the cylindrical body. In addition, in this heat-insulating support structure, a plurality of heat-insulating support units are formed by a plurality of hollow cylindrical bodies and radiant heat reflecting plate pieces, and the plurality of heat-insulating support units are integrated by joining the radiant heat reflecting plate pieces together. When a large radiant heat reflecting plate is prepared and arranged for a large storage tank, it is difficult to ensure the flatness of the radiant heat reflecting plate, and handling during transportation and arrangement is also difficult. In contrast, by unitizing the heat-insulating support structure using radiant heat reflecting plate pieces that have been previously divided from the radiant heat reflecting plate, problems of flatness and ease of handling can be eliminated, and ease of construction on a large storage tank can be ensured.

[0010] [2] In the heat insulating support structure according to [1], in each of the heat insulating support units, the hollow cylinders are composed of a central cylinder located at the center and a plurality of peripheral cylinders arranged to surround the central cylinder. In this case, the hollow cylinders can be densely arranged relative to the radiant heat reflecting plate pieces. Therefore, the buckling strength of the heat insulating support structure can be sufficiently increased.

[0011] [3] In the heat-insulating support structure according to [1] or [2], in each of the heat-insulating support units, the hollow cylindrical bodies are bundled together by a restraining member. In this case, it is possible to prevent the hollow cylindrical bodies from shifting from their original positions during construction, thereby improving workability during construction.

[0012] [4] The heat insulating support structure according to any one of [1] to [3], wherein a hole communicating with the internal space is provided in the peripheral wall of each of the plurality of hollow cylindrical bodies. The heat insulating support structure is used, for example, in a vacuum state after being installed in a storage tank. By providing a hole communicating with the internal space in the peripheral wall of the cylindrical body, the entire plurality of hollow cylindrical bodies can be easily evacuated.

[0013] [5] The heat insulating support structure according to any one of [1] to [4], wherein the ratio of the length of opposite sides in a plan view to the height of each of the hollow cylindrical bodies is at least 1. In this case, the hollow cylindrical bodies have a flat shape, so that the buckling strength of the heat insulating support structure is improved. The improved buckling strength makes it possible to reduce the wall thickness of the cylindrical body (to increase the hollow portion), thereby further improving the heat insulating properties.

[0014] [6] The heat-insulating support structure according to any one of [1] to [5], in which a plurality of heat-insulating support units are integrated into a joint body and stacked in a plurality of stages, thereby making it possible to more sufficiently increase the heat insulation and buckling strength of the heat-insulating support structure.

[0015] [7] The heat insulating support structure according to any one of [1] to [6], wherein each of the plurality of hollow cylindrical bodies has a cylindrical shape, and the radiant heat reflecting plate pieces have a regular polygonal shape. By making the cylindrical bodies cylindrical, the configuration of the cylindrical bodies is simplified, and the manufacturing cost of the heat insulating support structure can be reduced. On the other hand, by making the radiant heat reflecting plate pieces have a regular polygonal shape, it is possible to join the radiant heat reflecting plates together without any gaps, and the heat insulating properties can be sufficiently ensured.

[0016] [8] The heat-insulating support structure according to any one of [1] to [7], wherein each of the plurality of hollow cylindrical bodies is made of a fiber-reinforced plastic containing reinforcing fibers and a matrix resin. In this case, it is possible to provide the cylindrical bodies with sufficient heat insulation properties and buckling strength.

[0017] [9] The insulating support structure according to [8], wherein the reinforcing fibers have quasi-isotropy. In this case, the resistance to torsional stress in the cylindrical body is increased, and the earthquake resistance of the insulating support structure can be sufficiently improved.

[0018]

[10] The heat insulating support structure according to [8] or [9], wherein the glass transition temperature of the matrix resin is 100° C. or higher. In this case, the cylindrical body can have sufficient heat resistance to a baking process during evacuation.

[0019]

[11] The heat insulating support structure according to any one of [8] to

[10] , wherein the product of the breaking strength and breaking strain in a bending strength test at room temperature of the matrix resin is equal to or greater than 800. In this case, the cylindrical body can have sufficient toughness and low-temperature crack resistance at room temperature.

[0020]

[12] The heat insulating support structure according to any one of [8] to

[11] , wherein the loss tangent of the matrix resin at -100°C in a dynamic viscoelasticity test is 0.045 or more. In this case, the viscoelasticity of the cylindrical body at low temperatures can be sufficiently ensured. Therefore, even if the heat insulating support structure is cooled by stored items, the occurrence of cracks in the cylindrical body can be suppressed. Effect of the Invention

[0021] According to the present disclosure, ease of manufacturing and ease of installation in large storage tanks can be ensured. [Brief description of the drawings]

[0022] [Figure 1] 1 is a schematic cross-sectional view showing an example of the configuration of a gas storage tank to which an insulating support structure according to an embodiment of the present disclosure is applied. [Diagram 2] FIG. 2 is a perspective view of the heat insulating support structure according to the embodiment. [Diagram 3] FIG. 3 is a plan view of the insulating support structure shown in FIG. 2. [Figure 4] FIG. 3 is a side view of the insulating support structure shown in FIG. 2. [Diagram 5] FIG. 11 is a perspective view of a heat insulating support structure according to a modified example. [Figure 6] FIG. 11 is a perspective view of a heat insulating support structure according to another modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, a preferred embodiment of a thermal insulation support structure according to one aspect of the present disclosure will be described in detail with reference to the drawings.

[0024] Fig. 1 is a schematic cross-sectional view showing an example of the configuration of a storage tank to which a thermal insulation support structure according to an embodiment of the present disclosure is applied. The storage tank 1 shown in the figure is configured as a tank for storing liquid hydrogen G obtained by liquefying hydrogen gas, for example. The storage tank 1 is a cylindrical tank having a so-called double shell structure, including an inner tank 2 and an outer tank 3. A space E between the inner tank 2 and the outer tank 3 is maintained in a vacuum state. A thermal insulation support structure 11, which will be described later, is disposed in the space.

[0025] The inner tank 2 is a portion in which liquid hydrogen is stored. The inner tank 2 is made of, for example, stainless steel, and includes a bottom plate 2A, a side plate 2B, and a roof plate 2C. The outer tank 3 is provided so as to surround the inner tank 2. The outer tank 3 is made of, for example, ordinary steel plate, and includes a bottom plate 3A, a side plate 3B, and a roof plate 3C, similar to the inner tank 2. The bottom plate 3A of the outer tank 3 is firmly fixed onto a foundation P via anchor bolts (not shown). The outer surfaces of the side plates 3B and roof plate 3C of the outer tank 3 may be provided with a reinforcing structure to increase the buckling strength of the outer tank 3.

[0026] A support layer 4 made of, for example, insulating concrete is provided on the bottom plate 3A of the outer tank 3, and a floor plate 5 is provided on the support layer 4. The insulating concrete constituting the support layer 4 is, for example, perlite concrete. The floor plate 5 is made of, for example, ordinary steel plate. The outer edge of the floor plate 5 is firmly joined to the lower edge of the side plate 3B by, for example, welding.

[0027] In the space E between the inner tank 2 and the outer tank 3, a heat insulating support structure 11 is disposed between the bottom plate 2A of the inner tank 2 and the bottom plate 3A of the outer tank 3 to support the inner tank 2. FIG. 2 is a perspective view of the heat insulating support structure 11. FIG. 3 is a plan view of the heat insulating support structure 11, and FIG. 4 is a side view. As shown in FIGS. 2 to 4, the heat insulating support structure 11 is composed of a plurality of radiant heat reflecting plates 12 and a plurality of hollow cylindrical bodies 13.

[0028] In the heat insulating support structure 11, multiple radiant heat reflecting plates 12 and cylindrical bodies 13 are alternately stacked in the height direction of the storage tank 1. In this embodiment, the cylindrical bodies 13 of each stage are located at the same position when viewed from the stacking direction. In this embodiment, a radiant heat reflecting plate 12 is disposed at both stacking ends in the height direction of the heat insulating support structure 11. The radiant heat reflecting plate 12 of the bottom layer is in contact with the floor plate 5 of the outer tank 3, and the radiant heat reflecting plate 12 of the top layer is in contact with the bottom plate 2A of the inner tank 2. The radiant heat reflecting plate 12 of the top layer may be omitted, and the cylindrical body 13 may be in direct contact with the bottom plate 2A of the inner tank 2.

[0029] The radiant heat reflector 12 is a member that reflects radiant heat in the space E between the inner tank 2 and the outer tank 3. The radiant heat reflector 12 is made of, for example, a stainless steel plate or an aluminum plate. The radiant heat reflector 12 may be made of a plate-like member made of fiber-reinforced plastic, the surface of which is covered with an aluminum sheet. The thickness of the radiant heat reflector 12 is not particularly limited, but is, for example, about several mm to several tens of mm.

[0030] The cylindrical bodies 13 are formed in a hollow cylindrical shape with both axial ends open. Each of the cylindrical bodies 13 has a cylindrical internal space S (see Figs. 2 and 3) with a diameter slightly smaller than the outer diameter of the cylindrical body 13. The cylindrical bodies 13 are arranged on the radiant heat reflecting plate 12 so that the axial direction coincides with the height direction of the storage tank 1. The peripheral wall of each of the cylindrical bodies 13 is provided with a hole 14 (see Figs. 2 and 4) that communicates with the internal space S. In each of the multiple cylindrical bodies 13, the shape, size, and position of the hole 14 may be the same as or different from each other.

[0031] In each of the multiple cylindrical bodies 13, the ratio of the opposite side length in a plan view to the height is 1 or more. In this embodiment, since the shape of the cylindrical body 13 in a plan view is a circle, the opposite side length in a plan view is equal to the outer diameter of the cylindrical body 13. For example, when the shape of the cylindrical body 13 in a plan view is a regular hexagon, the opposite side length in a plan view is the distance between two opposing sides. The ratio of the opposite side length in a plan view to the height being 1 or more means that the cylindrical body 13 has a square shape when viewed from the side, or the cylindrical body 13 has a flat shape that is longer in the horizontal direction than in the height direction. The ratio of the opposite side length in a plan view to the height is preferably 1 or more, and more preferably 1.5 or more.

[0032] In this embodiment, as an example, the outer diameter of the cylindrical body 13 is about 50 cm to 1 m, and the height of the cylindrical body 13 is about 1 m in total for the three stages. The wall thickness of the cylindrical body 13 is about 3 mm. In this embodiment, the shape and dimensions of the cylindrical body 13 of each stage are the same, but the shape and dimensions of the cylindrical body 13 of each stage may be different from each other. For example, the height of the cylindrical body 13 of each stage may be different from each other, and the outer diameter of the cylindrical body 13 of each stage may be different from each other.

[0033] The cylindrical body 13 is formed of, for example, fiber-reinforced plastic. More specifically, in order to provide the cylindrical body 13 with sufficient heat insulation and buckling strength, the cylindrical body 13 is made of fiber-reinforced plastic containing reinforcing fibers and a matrix resin. Examples of the reinforcing fiber material that can be used include glass fiber, carbon fiber, and organic fiber. Examples of the matrix resin material that can be used include epoxy resin, vinyl ester resin, phenol resin, and polyester resin.

[0034] In this embodiment, the reinforcing fibers have quasi-isotropy in order to provide the cylindrical body with resistance to torsional stress. The quasi-isotropy refers to a property in which the physical properties are made equal in the 0° direction, 90° direction, and ±45° direction by using a combination of fibers, thereby exhibiting quasi-isotropy.

[0035] In this embodiment, the area where the heat insulating support structure 11 is arranged, i.e., the space between the bottom plate 2A of the inner tank 2 and the bottom plate 3A of the outer tank 3, is in a vacuum state. When evacuating the space, a baking treatment is carried out to remove adhesions of the fiber reinforced plastic constituting the cylindrical body 13. From the viewpoint of ensuring sufficient heat resistance against this baking treatment, the glass transition temperature of the matrix resin is set to 100°C or higher. The glass transition temperature of the matrix resin is preferably 100°C or higher, and more preferably 120°C or higher.

[0036] In this embodiment, from the viewpoint of imparting sufficient toughness at room temperature to the cylindrical body 13, the product of the breaking strength and breaking strain in a bending strength test at room temperature of the matrix resin is set to 800 or more. The product is preferably 800 or more, and more preferably 900 or more.

[0037] In this embodiment, the loss tangent at −100° C. in a dynamic viscoelasticity test of the matrix resin is set to 0.045 or more from the viewpoint of imparting sufficient viscoelasticity at low temperatures to the cylindrical body 13. The loss tangent is preferably 0.045 or more, and more preferably 0.05 or more.

[0038] The above-mentioned insulating support structure 11 is constructed by joining multiple insulating support units 21, 21 to each other, as shown in Figures 3 and 4, in order to ensure ease of manufacture and ease of installation on the storage tank 1.

[0039] The heat insulating support unit 21 is composed of a radiant heat reflecting plate piece 22 and the above-mentioned multiple hollow cylindrical bodies 13. The radiant heat reflecting plate piece 22 is a plate piece obtained by dividing the radiant heat reflecting plate 12 into a predetermined shape. The planar shape of the radiant heat reflecting plate piece 22 is not particularly limited as long as it can be joined together without gaps, and is, for example, a regular polygon. In this embodiment, as shown in Figs. 3 and 4, the radiant heat reflecting plate piece 22 is a regular hexagon.

[0040] In the heat insulating support unit 21, a plurality of cylindrical bodies 13 are arranged in the in-plane direction of the radiant heat reflecting plate piece 22 so that at least one of the openings at both ends in the axial direction is blocked. Here, the plurality of cylindrical bodies 13 are not joined to the radiant heat reflecting plate piece 22, and are simply placed on the radiant heat reflecting plate piece 22. Note that the plurality of cylindrical bodies 13 may be joined to the radiant heat reflecting plate piece 22 by an adhesive, a jig, or the like.

[0041] In this embodiment, in each of the heat insulating support units 21, the multiple cylindrical bodies 13 are composed of a central cylindrical body 13A located at the center and multiple peripheral cylindrical bodies 13B arranged to surround the central cylindrical body 13A. In the example of FIG. 3 and FIG. 4, the central cylindrical body 13A is arranged at the center of the radiant heat reflecting plate piece 22 having a regular hexagonal shape, and six peripheral cylindrical bodies 13B are arranged to surround the central cylindrical body 13A. In a plan view of the heat insulating support unit 21, the central cylindrical body 13A and each peripheral cylindrical body 13B are in contact with each other, and adjacent peripheral cylindrical bodies 13B, 13B are also in contact with each other. It is preferable that the peripheral cylindrical bodies 13B, 13B of adjacent heat insulating support units 21 are in contact with each other, but they may be spaced apart. Even when the peripheral cylindrical bodies 13B, 13B of adjacent insulating support units 21 are spaced apart from each other, the space between the peripheral wall portions of the peripheral cylindrical bodies 13B, 13B is blocked by the above-mentioned radiant heat reflecting plate 12, and therefore has an insulating function.

[0042] As shown in Figs. 2 to 4, the central cylinder 13A and each peripheral cylinder 13B are bound by a binding member 23. For example, a fiber-reinforced plastic sheet or tape can be used as the binding member 23. The binding member 23 is arranged so as to connect the side wall portions of each peripheral cylinder 13B. In the example of Fig. 2, one binding member is provided near the center in the height direction of each peripheral cylinder 13B. A plurality of binding members 23 may be provided in the height direction of each peripheral cylinder 13B.

[0043] The radiant heat reflecting plate 12 and the cylindrical body 13 of each stage are formed by joining the radiant heat reflecting plate pieces 22, 22 of the above-mentioned multiple heat insulating support units 21 together to form an integrated body of the heat insulating support units 21, 21. The heat insulating support structure 11 is formed in the storage tank 1 by forming and stacking the radiant heat reflecting plate 12 and the cylindrical body 13 of each stage in order from the lower stage side.

[0044] As described above, in the heat insulating support structure 11, each of the plurality of hollow cylindrical bodies 13 is placed on the radiant heat reflecting plate piece 22 so that at least one of the openings at both ends in the axial direction is blocked. By configuring the plurality of hollow cylindrical bodies 13 to have their openings blocked by a common radiant heat reflecting plate piece 22, it is possible to increase ease of manufacture compared to a configuration in which a radiant heat reflecting plate is disposed inside the cylindrical body. In addition, in the heat insulating support structure 11, a plurality of heat insulating support units 21 are formed by the plurality of hollow cylindrical bodies 13 and the radiant heat reflecting plate piece 22, and the plurality of heat insulating support units 21, 21 are integrated by joining the radiant heat reflecting plate pieces 22, 22 together. When preparing and disposing a large radiant heat reflecting plate for a large storage tank 1, it is difficult to ensure the flatness of the radiant heat reflecting plate, and handling during transportation and disposition is also difficult. In response to this, by unitizing the insulating support structure using radiant heat reflecting plate pieces 22 that are pre-divided from the radiant heat reflecting plate 12, problems with flatness and ease of handling can be eliminated, and ease of installation on large storage tanks 1 can be ensured.

[0045] In this embodiment, in each of the heat insulating support units 21, the multiple hollow cylinders 13 are composed of a central cylinder 13A located at the center and multiple peripheral cylinders 13B arranged to surround the central cylinder 13A. With this configuration, the multiple hollow cylinders 13 can be densely arranged relative to the radiant heat reflecting plate pieces 22. Therefore, the buckling strength of the heat insulating support structure 11 can be sufficiently increased.

[0046] In this embodiment, in each of the heat insulation support units 21, the multiple hollow cylindrical bodies 13 are bundled together by the restraining member 23. This makes it possible to prevent the multiple hollow cylindrical bodies 13 from shifting in position during construction, and improves workability when constructing the heat insulation support unit 21 on the storage tank 1.

[0047] In this embodiment, a hole 14 communicating with the internal space S is provided in the peripheral wall of each of the plurality of hollow cylindrical bodies 13. By providing such a hole 14, the entirety of the plurality of hollow cylindrical bodies 13 can be easily evacuated.

[0048] In this embodiment, the ratio of the length of opposite sides in a plan view to the height of each of the multiple hollow cylindrical bodies 13 is equal to or greater than 1. In this case, the multiple hollow cylindrical bodies 13 have a flat shape, which improves the buckling strength of the heat-insulating support structure 11. The improvement in buckling strength makes it possible to reduce the wall thickness of the cylindrical body 13 (to increase the hollow portion), thereby further improving the heat insulation.

[0049] In this embodiment, a plurality of heat insulating support units 21 are integrated into a joint body, which is stacked in multiple stages. This allows a plurality of radiant heat reflecting plates 12 and a plurality of cylindrical bodies 13 to be disposed between the bottom plate 2A of the inner tank 2 and the bottom plate 3A of the outer tank 3, thereby further improving the heat insulating property and buckling strength of the heat insulating support structure 11.

[0050] In this embodiment, each of the multiple hollow tubular bodies 13 has a cylindrical shape, and the radiant heat reflecting plate pieces 22 have a regular polygonal shape. By making the tubular bodies 13 cylindrical, the configuration of the tubular bodies 13 is simplified, and the manufacturing costs of the heat-insulating support structure 11 can be reduced. On the other hand, by making the radiant heat reflecting plate pieces 22 have a regular polygonal shape, it becomes possible to join the radiant heat reflecting plate pieces 22, 22 together without any gaps, and sufficient heat insulation can be ensured.

[0051] In this embodiment, each of the hollow cylindrical bodies 13 is made of fiber-reinforced plastic containing reinforcing fibers and a matrix resin. In this case, it is possible to provide the cylindrical body 13 with sufficient heat insulation and buckling strength. In addition, in this embodiment, the reinforcing fibers have pseudo-isotropy. In this case, the resistance of the cylindrical body 13 to torsional stress is increased, and the earthquake resistance of the heat-insulating support structure 11 can be sufficiently improved.

[0052] In this embodiment, the glass transition temperature of the matrix resin is 100°C or higher. In this case, the cylindrical body 13 can be sufficiently secured to have heat resistance against the baking process during evacuation. In addition, in this embodiment, the product of the breaking strength and breaking strain in a bending strength test at room temperature of the matrix resin is 800 or higher. This allows the cylindrical body 13 to be sufficiently secured to have toughness and low-temperature crack resistance at room temperature. Furthermore, in this embodiment, the loss tangent at -100°C in a dynamic viscoelasticity test of the matrix resin is 0.045 or higher. This allows the cylindrical body 13 to be sufficiently secured to have viscoelasticity at low temperatures. Therefore, even if the heat insulating support structure 11 is cooled by the stored liquid hydrogen G, it is possible to suppress the occurrence of cracks in the cylindrical body 13.

[0053] The present disclosure is not limited to the above embodiment. For example, in the above embodiment, the cylindrical bodies 13 of each stage are located at the same position when viewed from the stacking direction, but as shown in Fig. 5, the cylindrical bodies 13 of each stage may be located at different positions when viewed from the stacking direction. In this case, the positions of the cylindrical bodies 13 of each stage (positions in the in-plane direction of the radiant heat reflector 12) may be staggered for each stage, or the positions of the cylindrical bodies 13 of each stage may all be shifted.

[0054] In the above embodiment, the cylindrical body 13 has a cylindrical shape, and the radiant heat reflecting plate piece 22 has a regular hexagonal shape, but the shapes of the cylindrical body 13 and the radiant heat reflecting plate piece 22 are not limited thereto. For example, as shown in Fig. 6, the cylindrical body 13 may have a cylindrical shape, while the radiant heat reflecting plate piece 22 may have a rectangular shape. In this case, for example, by arranging the cylindrical body 13 in a lattice pattern on the radiant heat reflecting plate piece 22, in the joined body in which the thermal insulation support units 21, 21 are integrated, the cylindrical bodies 13, 13 of adjacent thermal insulation support units 21 can be in contact with each other.

[0055] The shape of the tubular body 13 is not limited to a cylindrical shape, and may be another polygonal cylindrical shape, such as a hexagonal cylindrical shape. The shape of the radiant heat reflecting plate pieces 22 is also not limited to a regular hexagon or a rectangle, and may be another regular polygonal shape, such as an equilateral triangle, a square, or a regular pentagon. The shape of the radiant heat reflecting plate pieces 22 may be any shape other than a regular polygon, as long as the radiant heat reflecting plate pieces 22, 22 can be joined together without any gaps.

[0056] [Example] Examples of the present disclosure will be described below. Here, fiber-reinforced plastics obtained by impregnating glass fibers, carbon fibers, or the like with a resin composition and curing the resin composition were prepared as Examples 1 to 3 and Comparative Examples 1 and 2. For the samples of each Example and Comparative Example, bending strength tests, dynamic viscoelasticity tests, and glass transition temperature measurements were performed as physical properties of the matrix resin alone, and low-temperature crack resistance tests were also performed as evaluations of the fiber-reinforced plastics. The physical properties of the matrix resin alone and the low-temperature crack resistance test results of each Example and Comparative Example are summarized in Table 1.

[0057] (Bending strength test) The bending strength and breaking elongation of the matrix resin cured material were measured under the following conditions using an autograph (AG-X50kNXPlus manufactured by Shimadzu Corporation). The bending strength corresponds to the breaking strength in this disclosure, and the breaking elongation corresponds to the breaking strain in this disclosure. Test piece: Resin hardened material, 3.5 mm thick, 10 mm wide, 70 mm long ·Distance between fulcrums: 58mm Test speed: 2mm / min ·Measurement temperature: 25℃

[0058] (Dynamic viscoelasticity test) Using a dynamic mechanical analyzer (RSA-G2 manufactured by TA instruments), the loss tangent tan δ of the matrix resin alone cured product at −100° C. was measured under the following conditions. Measurement temperature range: -150℃~200℃ Heating rate: 5℃ / min ·Measurement frequency: 1Hz

[0059] (glass transition temperature) The glass transition temperature Tg of the matrix resin alone cured product was measured under the following conditions using a thermomechanical analyzer (TMA / SS7100 manufactured by Hitachi High-Tech Science Corporation). Measurement temperature range: 25℃~200℃ Heating rate: 5℃ / min Test mode: Expansion Load: 5g

[0060] (Low temperature crack resistance test) Using an electron microscope (Hitachi High-Tech Corporation TM4000Plus2), the low-temperature crack resistance of fiber reinforced plastics was evaluated under the following conditions. Test piece: 150mm x 110mm x 5mm Cooling solvent: Liquid nitrogen (-196℃) Evaluation method: The test piece was immersed in liquid nitrogen for 30 minutes, then left at room temperature for 30 minutes, which counted as one cycle, and a total of three cycles were performed. After the three cycles, the test piece was cut in the center and the cross section was observed under the above-mentioned electron microscope. Those with no cracks on the cross section were evaluated as "OK", and those with cracks on the cross section were evaluated as "NG".

[0061] Example 1 After mixing 100 parts of alicyclic epoxy resin (Celloxide 2021P manufactured by Daicel Corporation), 100 parts of acid anhydride curing agent (HN-2200 manufactured by Resonac Corporation), and 0.5 parts of curing accelerator (N,N-dimethylbenzylamine), the mixture was cured at 70°C for 15 hours, at 125°C for 6 hours, and at 160°C for 10 hours to obtain an epoxy resin cured product according to Example 1. The bending strength A of the resin cured product in Example 1 alone was 166MPa, the breaking elongation B was 7.3%, the product of the bending strength A and the breaking elongation B was 1212, the loss tangent tanδ at -100°C was 0.050, and the glass transition temperature Tg was 170°C.

[0062] The resin mixture before curing was impregnated into glass fiber (Q880G manufactured by SHINDO Co., Ltd.), and then cured at 70°C for 15 hours, 125°C for 6 hours, and 160°C for 10 hours to produce a glass fiber reinforced plastic. This glass fiber reinforced plastic was immersed in liquid nitrogen and the above-mentioned low-temperature crack resistance test was carried out. When the cross section of the test piece was observed under an electron microscope, no cracks were found, and good results were obtained.

[0063] Example 2 100 parts of bisphenol A type epoxy resin (jER828 manufactured by Mitsubishi Chemical Corporation), 90 parts of acid anhydride curing agent (HN-2200 manufactured by Resonaq), and 1 part of curing accelerator (N,N-dimethylbenzylamine) were mixed and cured at 140°C for 4 hours to obtain a cured epoxy resin material according to Example 2. The cured resin material of Example 2 had a flexural strength A of 145 MPa, a breaking elongation B of 6.3%, a product of the flexural strength A and the breaking elongation B of 914, a loss tangent tanδ at -100°C of 0.048, and a glass transition temperature Tg of 117°C.

[0064] The resin mixture before curing was impregnated into glass fiber (Q880G manufactured by SHINDO Co., Ltd.) and cured at 140°C for 4 hours to produce a glass fiber reinforced plastic. This glass fiber reinforced plastic was immersed in liquid nitrogen and the above-mentioned low-temperature crack resistance test was carried out. When the cross section of the test piece was observed with an electron microscope, no cracks were found, and good results were obtained.

[0065] Example 3 100 parts of vinyl ester resin (Resonac Lipoxy R-806), 1 part of polymerization initiator (NOF Corp. Permec N), and 1 part of curing accelerator (DIC Corp. Co-OCTOATE 6%) were mixed and then cured at room temperature for 24 hours and at 120°C for 2 hours to obtain a vinyl ester resin cured product according to Example 3. The resin alone cured product of Example 3 had a flexural strength A of 138 MPa, a breaking elongation B of 7.0%, a product of the flexural strength A and the breaking elongation B of 966, a loss tangent tanδ at -100°C of 0.055, and a glass transition temperature Tg of 106°C.

[0066] The resin mixture before curing was impregnated into glass fiber (Q880G manufactured by SHINDO Co., Ltd.), and then cured at room temperature for 24 hours and at 120°C for 2 hours to produce a glass fiber reinforced plastic. This glass fiber reinforced plastic was immersed in liquid nitrogen and the above-mentioned low-temperature crack resistance test was carried out. When the cross section of the test piece was observed under an electron microscope, no cracks were found, and good results were obtained.

[0067] Comparative Example 1 100 parts of unsaturated polyester resin (Sundoma 518-20, DIC Materials), 1 part of polymerization initiator A (Permec N, NOF Corp.), 2 parts of polymerization initiator B (Perbutyl Z, NOF Corp.), and 1 part of curing accelerator (Co-OCTOATE 6%, DIC Corp.) were mixed and cured at room temperature for 24 hours and at 120°C for 15 hours to obtain a polyester resin cured product according to Comparative Example 1. The bending strength A of the resin alone cured product of Comparative Example 1 was 130MPa, the breaking elongation B was 4.4%, the product of bending strength A and breaking elongation B was 572, the loss tangent tanδ at -100°C was 0.042, and the glass transition temperature Tg was 110°C.

[0068] The resin mixture before curing was impregnated into glass fiber (Q880G manufactured by SHINDO Co., Ltd.), and then cured at room temperature for 24 hours and at 120°C for 15 hours to produce a glass fiber reinforced plastic. This glass fiber reinforced plastic was immersed in liquid nitrogen and subjected to the above-mentioned low-temperature crack resistance test. When the cross section of the test piece was observed under an electron microscope, the occurrence of cracks was confirmed.

[0069] Comparative Example 2 100 parts of vinyl ester resin (PS6202 manufactured by DIC Materials Co., Ltd.), 1 part of polymerization initiator A (Permec N manufactured by NOF Corp.), 1 part of polymerization initiator B (Perbutyl Z manufactured by NOF Corp.), and 1 part of curing accelerator (Co-OCTOATE 6% manufactured by DIC Corp.) were mixed, and then cured at room temperature for 24 hours, at 120°C for 15 hours, and at 150°C for 10 hours to obtain a vinyl ester resin cured product according to Comparative Example 2. The bending strength A of the resin alone cured product of Comparative Example 2 was 156 MPa, the breaking elongation B was 5.0%, the product of the bending strength A and the breaking elongation B was 780, the loss tangent tanδ at -100°C was 0.043, and the glass transition temperature Tg was 154°C.

[0070] The resin mixture before curing was impregnated into glass fiber (Q880G manufactured by SHINDO Co., Ltd.), and then cured at room temperature for 24 hours, at 120°C for 15 hours, and at 150°C for 10 hours to produce a glass fiber reinforced plastic. This glass fiber reinforced plastic was immersed in liquid nitrogen and subjected to the above-mentioned low-temperature crack resistance test. When the cross section of the test piece was observed under an electron microscope, the occurrence of cracks was confirmed. [Table 1] [Explanation of symbols]

[0071] 1...storage tank, 2...inner tank, 2A...bottom plate, 3...outer tank, 3A...bottom plate, 11...insulating support structure, 13...cylindrical body, 13A...central cylindrical body, 13B...peripheral cylindrical body, 14...hole, 21...insulating support unit, 22...radiant heat reflecting plate piece, 23...restraining member.

Claims

1. A heat insulating support structure for a storage tank having an inner tank and an outer tank, the heat insulating support structure supporting the inner tank between a bottom plate of the inner tank and a bottom plate of the outer tank, The heat insulating support unit includes a plurality of heat insulating support units each including a radiant heat reflecting plate piece divided into a predetermined shape and a plurality of hollow cylindrical bodies arranged in the in-plane direction of the radiant heat reflecting plate piece and having both ends open in the axial direction, Each of the plurality of hollow cylindrical bodies is placed on the radiant heat reflecting plate piece so that at least one of the openings at both ends in the axial direction is blocked, A heat insulating support structure in which the multiple heat insulating support units are integrated together by joining the radiant heat reflecting plate pieces together.

2. The insulating support structure of claim 1, wherein in each of the insulating support units, the plurality of hollow cylindrical bodies are composed of a central cylindrical body located at the center and a plurality of peripheral cylindrical bodies arranged to surround the central cylindrical body.

3. The thermal insulation support structure according to claim 1 , wherein in each of the thermal insulation support units, the plurality of hollow cylindrical bodies are bound together by a restraining member.

4. The heat insulating support structure according to claim 1 , wherein a peripheral wall of each of the plurality of hollow cylindrical bodies is provided with a hole communicating with the internal space.

5. The heat insulating support structure according to claim 1 , wherein each of the plurality of hollow cylindrical bodies has a ratio of opposite side length in a plan view to height of 1 or more.

6. The heat insulating support structure according to claim 1 , wherein the assembly in which the plurality of heat insulating support units are integrated is stacked in a plurality of stages.

7. Each of the plurality of hollow cylindrical bodies has a cylindrical shape, The thermal insulation support structure of claim 1 , wherein the radiant heat reflecting plate pieces are in the shape of a regular polygon.

8. The heat insulating support structure according to any one of claims 1 to 7, wherein each of the plurality of hollow cylindrical bodies is made of a fiber reinforced plastic containing reinforcing fibers and a matrix resin.

9. The thermally insulating support structure of claim 8 , wherein the reinforcing fibers are quasi-isotropic.

10. The thermal insulation support structure according to claim 8 , wherein the matrix resin has a glass transition temperature of 100° C. or higher.

11. The thermal insulation support structure according to claim 8 , wherein the matrix resin has a product of breaking strength and breaking strain in a bending strength test at room temperature of 800 or more.

12. 9. The heat insulating support structure according to claim 8, wherein the loss tangent of the matrix resin at -100°C in a dynamic viscoelasticity test is 0.045 or more.

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