Construction Method of Triple Shell Storage Tank

Abstract

A construction method for a triple-shell storage tank comprising an inner trough, a middle trough, and an outer trough, each having a roof and side panels, includes the following sequence: A roof connector is formed by temporarily fixing the middle trough roof to the inner trough roof, and then temporarily fixing the outer trough roof to the middle trough roof. An outer trough side panel of a predetermined height is constructed around the roof connector. A sealed space is formed between the outer perimeter of the outer trough roof and the inner surface of the outer trough side panel, and air is supplied to this sealed space to aerate the roof connector. The outer trough roof and the outer trough side panel are then fixed. The inner trough side panel and the middle trough side panel are constructed, the temporary fixing of the roof connector is released, and the inner trough roof and the inner trough side panel are fixed, as are the middle trough roof and the middle trough side panel.

Description

Technical Field

[0001] This disclosure relates to a construction method for a triple-shell storage tank for storing cryogenic liquefied gases. Prior Technology

[0002] As facilities for storing cryogenic liquefied gases, flat-bottomed storage tanks with multi-shell structures are known. The construction of such multi-shell tanks generally requires a long construction period due to the large scale of the buildings themselves and the need for insulation. For example, Patent Documents 1 and 2 disclose construction methods for storage tanks with a double-shell structure including an inner and outer tank, aimed at shortening the construction period. In recent years, flat-bottomed storage tanks with a triple-shell structure including an intermediate tank between the inner and outer tanks have been studied as storage facilities for extremely low-temperature liquefied gases.

[0003] Compared to double-shell tanks, triple-shell tanks have a more complex structure, which tends to result in a longer construction period. [Existing Technical Documents] [Patent Literature]

[0004] [Patent Document 1] Japanese Patent No. 6127453 [Patent Document 2] Japanese Patent No. 5672787 Summary of the Invention

[0005] The purpose of this disclosure is to provide a construction method that can shorten the construction period when building a triple-shell storage tank including an inner tank, a middle tank and an outer tank.

[0006] The construction method of the triple-shell storage tank disclosed herein includes a construction method for an inner tank, a middle tank, and an outer tank, each having a roof and side panels. This method involves temporarily fixing the middle tank roof to the inner tank roof, and then temporarily fixing the outer tank roof to the middle tank roof to form a roof connector. An outer tank side panel of a predetermined height is constructed around the roof connector. A sealing treatment is performed between the outer perimeter of the outer tank roof and the inner surface of the outer tank side panel to form a sealed space, and air is supplied to the sealed space to perform air flotation on the roof connector. The outer tank roof and the outer tank side panel are then fixed. The inner tank side panel and the middle tank side panel are constructed. The temporary fixing of the roof connector is released, and the inner tank roof and the inner tank side panel are fixed. Finally, the middle tank roof and the middle tank side panel are fixed.

[0007] According to this disclosure, a construction method can be provided to shorten the construction period when constructing a triple-shell storage tank including an inner tank, an intermediate tank and an outer tank. Simple Explanation of the Diagram

[0008] [Figure 1] is a longitudinal sectional view showing the structure of the triple-shell storage tank that is the subject of this disclosure. [Figure 2] is a step diagram of the construction method of the triple-shell storage tank disclosed herein. [Figure 3] is a diagram showing one step of the construction method of the above-mentioned triple-shell storage tank in half of the cross section of the storage tank. [Figure 4] is a diagram showing one step of the construction method of the above-mentioned triple-shell storage tank. [Figure 5] is a diagram showing one step of the construction method of the above-mentioned triple-shell storage tank. [Figure 6] is a diagram showing one step of the construction method of the above-mentioned triple-shell storage tank. [Figure 7] is a diagram showing one step of the construction method of the above-mentioned triple-shell storage tank. [Figure 8] is a diagram showing one step of the construction method of the above-mentioned triple-shell storage tank. [Figure 9] is a diagram showing one step of the construction method of the above-mentioned triple-shell storage tank. [Figure 10] is a diagram showing one step of the construction method of the above-mentioned triple-shell storage tank. [Figure 11] is a diagram showing one step of the construction method of the above-mentioned triple-shell storage tank. [Figure 12] is a diagram showing one step of the construction method of the above-mentioned triple-shell storage tank. [Figure 13] is a diagram showing one step of the construction method of the above-mentioned triple-shell storage tank. [Figure 14] is a diagram showing one step of the construction method of the above-mentioned triple-shell storage tank. [Figure 15] is a diagram showing one step of the construction method of the above-mentioned triple-shell storage tank. [Figure 16] is a diagram showing one step of the construction method of the above-mentioned triple-shell storage tank. Implementation

[0009] The following describes in detail, with reference to the drawings, the implementation method of the construction method of the triple-shell storage tank disclosed herein. The triple-shell storage tank, the object of construction in this disclosure, is a storage tank for storing cryogenic liquefied gases, and is a flat-bottomed storage tank with a ground-mounted triple-shell structure. The stored liquefied gases include, for example, liquid hydrogen and liquid helium.

[0010] [Structure of a Triple-Shell Storage Tank] First, based on the longitudinal sectional view shown in Figure 1, the structure of the triple-shell storage tank 1, which is the subject of this disclosure, will be described. Figure 1 illustrates a triple-shell storage tank 1 for storing liquid hydrogen (LH). The triple-shell storage tank 1 includes: a storage tank foundation 10, an outer tank 2 erected on the storage tank foundation 10, an intermediate tank 3 enclosed within the outer tank 2, and an inner tank 4 enclosed within the intermediate tank 3. The outer tank 2, intermediate tank 3, and inner tank 4 all have a circular shape when viewed from above and are arranged in a concentric circle configuration.

[0011] The storage tank foundation 10 is a concrete layer that forms the foundation of the triple-shell storage tank 1. The storage tank foundation 10 has a larger outer diameter than the outer tank 2. The outer tank 2 is a sealed body made of metal such as carbon steel, including an outer tank bottom plate 21, outer tank side plates 22, and an outer tank roof 23. The outer tank bottom plate 21 is laid directly above the storage tank foundation 10 and has a circular plate shape. The outer tank side plates 22 are erected from the periphery of the outer tank bottom plate 21 and have a cylindrical shape. The outer tank roof 23 is installed on the upper end of the cylindrical outer tank side plates 22 by blocking the opening on the upper surface of the outer tank side plates 22, and has a dome shape.

[0012] The intermediate channel 3 is a sealed body made of metal such as SUS, and is disposed inside the outer channel 2. The intermediate channel 3 includes an intermediate channel bottom plate 31, intermediate channel side plates 32, and intermediate channel roof 33. The intermediate channel bottom plate 31 is a circular plate with a diameter smaller than that of the outer channel bottom plate 21. The intermediate channel side plates 32 are erected from the periphery of the intermediate channel bottom plate 31 and have a cylindrical shape. The intermediate channel roof 33 is installed on the upper end of the intermediate channel side plates 32 and has a dome shape.

[0013] Between the outer tank bottom plate 21 and the intermediate tank bottom plate 31, there exists a first-level concrete layer 24, a first ring portion 25, and an outer bottom insulation layer 26. The first-level concrete layer 24 is a concrete layer exposed on the outer tank bottom plate 21. The first ring portion 25 is a high-strength concrete layer arranged in a ring shape near the periphery of the first-level concrete layer 24. A reinforced concrete layer 251 is arranged in the portion of the first ring portion 25 that directly bears the load of the intermediate tank side plate 32. The outer bottom insulation layer 26 is an insulating layer arranged on the first-level concrete layer 24 and inside the first ring portion 25. The first ring portion 25 can be formed using an arrangement of insulating concrete blocks, such as perlite concrete blocks. The outer bottom insulation layer 26 can be formed using an arrangement of insulating inorganic block materials, such as foam glass. A lightweight foamed concrete board can also be laid on the outer bottom insulation layer 26.

[0014] The inner tank 4 is the actual tank for storing liquid. It is a sealed body made of metals such as SUS and is located inside the intermediate tank 3. The inner tank 4 includes an inner tank bottom plate 41, inner tank side plates 42, and inner tank roof 43. The inner tank bottom plate 41 has a circular plate shape with a diameter smaller than that of the intermediate tank bottom plate 31. The inner tank side plates 42 are erected from the periphery of the inner tank bottom plate 41 and have a cylindrical shape. The inner tank roof 43 is installed on the upper part of the inner tank side plates 42 and has a dome shape. Liquid hydrogen (LH) is stored inside the inner tank 4.

[0015] Between the intermediate tank bottom plate 31 and the inner tank bottom plate 41, there exists a second-level concrete layer 34, a second ring portion 35, and an inner bottom insulation layer 36. The second-level concrete layer 34 is constructed on the intermediate tank bottom plate 31. The second ring portion 35 is a high-strength concrete layer arranged in a ring shape near the periphery of the second-level concrete layer 34. In the second ring portion 35, where the load of the inner tank side plate 42 is directly borne, a reinforced concrete layer 351 is provided. The inner bottom insulation layer 36 is a heat-insulating layer disposed on the second-level concrete layer 34 and inside the second ring portion 35. For example, the second ring portion 35 can be formed of perlite concrete blocks, and the inner bottom insulation layer 36 can be formed of foam glass blocks, etc. A lightweight foamed concrete board can also be laid on the inner bottom insulation layer 36.

[0016] A predetermined gap of width is provided between the inner tank 4 and the intermediate tank 3, and between the intermediate tank 3 and the outer tank 2. The gap between the inner tank 4 and the intermediate tank 3 (the first gap 11) and the gap between the intermediate tank 3 and the outer tank 2 (the second gap 12) are filled with insulating material. The insulating material can be perlite or glass wool. The first gap 11 is filled with a low-boiling-point gas, such as hydrogen, equivalent to the liquid hydrogen (LH) stored in the inner tank 4. The second gap 12 is filled with, for example, nitrogen.

[0017] Construction Method for Triple-Shell Storage Tanks Next, the construction method of the triple-shell storage tank 1 illustrated in Figure 1 will be explained. Figure 2 is a step diagram showing one embodiment of the construction method of the triple-shell storage tank 1 disclosed herein. In Figure 2, the steps S1 to S14 performed during the construction period of the triple-shell storage tank 1 and their relationship to the construction period of each part of the triple-shell storage tank 1 are shown. Specifically, for each of the bottom plates 21, 31, 41, roof 23, 33, 43, and side plates 22, 32, 42 of the outer tank 2, the middle tank 3, and the inner tank 4, the actual construction period of the main construction work is shown with solid arrows, and the period after construction is shown with dashed lines, as shown in Figure 2. For the side plates 22, 32, and 42, the opening time of the engineering entrance, i.e., the engineering opening, is marked as "open", and the sealing time of the engineering opening is marked as "closed". Furthermore, steps S1 to S14 do not necessarily have to be divided into steps that become part of the construction sequence of the storage tank; there are also cases where the completion status of the project is simply divided into "steps".

[0018] Although there are annotations in Figure 2, the characteristic of the construction method in this embodiment is that a roof connector is formed by ground-based operations, temporarily fixing the intermediate tank roof 33 and the inner tank roof 43 to the outer tank roof 23 (step S6), and the roof connector is made to float by air flotation (step S8). Figures 3 to 16 are schematic diagrams showing the construction state of the triple-shell storage tank 1 in steps S1 to S14 of Figure 2, respectively. In Figures 3 to 16, the portion corresponding to half of the triple-shell storage tank 1 from the radial center RC is shown in cross-section. Hereinafter, steps S1 to S14 will be described with reference to Figures 3 to 16.

[0019] <Step S1> Figure 3 shows the construction status of step S1. In step S1, a portion of the outer tank 2 is installed on the storage tank foundation 10. Specifically, an outer tank wheel 211, which constitutes part of the outer tank bottom plate 21, and an outer tank side plate member 22P1, which constitutes part of the outer tank side plate 22, are installed near the periphery of the storage tank foundation 10. The outer tank wheel 211 forms an annular portion near the outer periphery of the circular outer tank bottom plate 21, becoming the portion located below the first annular portion 25. To improve load-bearing capacity, the outer tank wheel 211 has a thicker plate than other parts of the outer tank bottom plate 21.

[0020] The outer groove side plate 22 is assembled using a plurality of side plate pieces, including rectangular plates that are gradually bent into an arc shape. Specifically, the side plate pieces are arranged in a ring shape, and adjacent side plate pieces are welded together to form a ring segment. The outer groove side plate 22 is constructed by stacking a plurality of such ring segments. Figure 3 shows the outer groove side plate piece 22P1, which is the side plate piece constituting the lowermost ring segment of the outer groove side plate 22. The outer groove side plate piece 22P1 is erected vertically upward from slightly inside the radially outer periphery of the outer groove wheel 211.

[0021] <Step S2> Figure 4 shows the construction status of step S2. In step S2, the outer channel bottom plate 21 and the outer channel side plate 22 are constructed. Regarding the outer channel bottom plate 21, the radially inner portion of the outer channel wheel 211 is laid. This inner portion is located directly below the outer bottom insulation layer 26. Although not shown in Figure 4, the first-level concrete layer 24 shown in Figure 1 is poured on the outer channel bottom plate 21 after it is laid. First, a portion of the first-level concrete layer 24 is poured on the outer channel wheel 211. Then, after constructing the inner channel roof 43 and the intermediate channel roof 33 to eliminate concerns about rainwater intrusion, the remainder of the first-level concrete layer 24 is poured on the inner portion of the outer channel wheel 211.

[0022] Regarding the outer groove side plate 22, an outer groove side plate 22P2 constituting the second annular section is installed on the outer groove side plate 22P1 constituting the lowest annular section. Furthermore, after the second annular section is constructed, a first opening OP1, serving as an engineering opening, is provided in the lowest annular section. The first opening OP1 is created by removing one or more of the plurality of outer groove side plates 22P1 constituting the lowest annular section. Specifically, after arranging the plurality of outer groove side plates 22P1 in a ring to temporarily form an annular section, the outer groove side plate 22P1 corresponding to the position of the first opening OP1 is not welded to adjacent parts and is removed from the annular section.

[0023] A central roof platform 51 is provided near the radial center RC of the outer tank bottom plate 21. The central roof platform 51 is a platform for constructing the dome-shaped inner tank roof 43 on the ground side before air flotation.

[0024] <Step S3> Figure 5 shows the construction status of step S3. In step S3, the construction of the outer channel side plate 22 continues, and the construction of the inner channel roof 43 begins. Regarding the outer channel side plate 22, an outer channel side plate 22P3 constituting the third annular section is installed on the outer channel side plate 22P2 constituting the second annular section. Similarly, after the construction of the third annular section, one or more outer channel side plates 22P2 in the second annular section are removed, thereby opening the first opening OP1 as the engineering opening. The removed outer channel side plate 22P2 is located directly above the outer channel side plate 22P1 removed in the lowest annular section to open the first opening OP1. The reason for opening the first opening OP1 at the height of the two sections of the annular segment on the outer side plate 22 is to make the opening height consistent with the engineering openings opened on the intermediate side plate 32 and the inner side plate 42, which are constructed from a position higher than the outer side plate 22.

[0025] Regarding the inner channel roof 43, an inner channel roof member 43P constituting the inner channel roof 43 is installed on the central roof support 51 set in the previous step S2, near the radial center. On the other hand, an outer peripheral roof support 52 is installed on the upper surface near the radial outer periphery of the outer channel bottom plate 21. The outer peripheral roof support 52 is a support that temporarily supports the lower outer periphery of the inner channel roof 43 and the intermediate channel roof 33. An inner channel steering knuckle plate 44 is installed on the upper surface of the outer peripheral roof support 52. The inner channel steering knuckle plate 44 is a plate that connects the upper end of the inner channel side plate 42 to the lower outer periphery of the inner channel roof 43.

[0026] <Step S4> Figure 6 illustrates the construction status of step S4. In step S4, the construction of the inner channel roof 43 continues, while the construction of the intermediate channel roof 33 begins. Regarding the inner channel roof 43, it is formed by connecting the radially central inner channel roof component 43P installed in step S3 to the inner channel steering knuckle plate 44 using pre-assembled inner channel roof blocks assembled on the ground, ultimately creating a dome-shaped inner channel roof 43. The aforementioned inner channel roof block includes: a roof frame that serves as a supporting framework, and a plurality of roof panels installed on the roof frame. The outer periphery 43E of the inner channel roof 43 is fixed to the upper end of the inner channel steering knuckle plate 44. At this point, the inner channel roof 43 becomes self-supporting, supported by the outer periphery roof platform 52, and therefore the central roof platform 51 is removed.

[0027] Regarding the intermediate channel roof 33, an intermediate channel roof member 33P constituting the radial center of the intermediate channel roof 33 is installed on the radial center portion of the inner channel roof 43 completed in step S3. During this installation, an intermediate channel roof support 61 (first temporary support) is used. The intermediate channel roof support 61 exists between the inner channel roof 43 and the intermediate channel roof 33, temporarily fixing them apart by a predetermined interval. The intermediate channel roof support 61 can be a rigid component such as an H-beam. For example, the temporary fixing can be implemented by welding the lower end of the H-beam to the inner channel roof 43 via a predetermined pad, with the intermediate channel roof member 33P placed and fixed on the upper end of the H-beam.

[0028] The construction of the outer channel side plate 22 also continues as appropriate. Figure 6 shows the state in which the outer channel side plate member 22P4 constituting the fourth segment is installed. Furthermore, the intermediate channel steering knuckle plate 37 is installed on the upper surface of the outer perimeter roof platform 52. The intermediate channel steering knuckle plate 37 is a plate that connects the upper end of the intermediate channel side plate 32 to the lower edge of the outer perimeter of the intermediate channel roof 33. Furthermore, a block constituting the first ring 25 is laid on the upper surface near the radial outer perimeter of the outer channel bottom plate 21.

[0029] <Step S5> Figure 7 shows the construction status of step S5. In step S5, the construction of the intermediate channel roof 33 continues, and the construction of the outer channel roof 23 begins. Also, the construction of the intermediate channel bottom plate 31 and the intermediate channel side plate 32 begins. Regarding the intermediate channel roof 33, a dome-shaped intermediate channel roof 33 is ultimately formed by connecting the radially central intermediate channel roof component 33P set in step S4 to the intermediate channel steering knuckle plate 37 using an intermediate channel roof block pre-assembled through ground work. The aforementioned intermediate channel roof block, like the aforementioned inner channel roof block, includes a roof frame and multiple roof panels. During the installation of the intermediate channel roof block, the intermediate channel roof support 61 is positioned appropriately between the intermediate channel roof 33 and the inner channel roof 43, and both are temporarily fixed. The outer periphery 33E of the intermediate channel roof 33 is fixed to the upper end of the intermediate channel steering knuckle plate 37.

[0030] Regarding the outer trough roof 23, an outer trough roof member 23P constituting the radial center of the outer trough roof 23 is installed on the radial center portion of the intermediate trough roof 33 completed in step S4. During this installation, an outer trough roof central support 62 (second temporary support) is used. The outer trough roof central support 62 exists between the intermediate trough roof 33 and the radially central outer trough roof member 23P, temporarily fixing them at a predetermined interval. The outer trough roof central support 62 can be a platform or the like, constructed by assembling H-beams or steel into a truss structure. This temporary fixing is achieved by welding the lower end of the H-beam or the like to the intermediate trough roof 33 via a predetermined pad, thus placing and fixing the outer trough roof member 23P on the upper end of the H-beam or the like.

[0031] On the first ring portion 25 set in the previous step S4, an intermediate groove wheel 311, which constitutes part of the intermediate groove bottom plate 31, and an intermediate groove side plate member 32P1 (side plate member), which constitutes part of the intermediate groove side plate 32, are installed. The intermediate groove wheel 311 is an annular portion near the outer periphery of the circular plate-shaped intermediate groove bottom plate 31, and has a plate thickness that is thicker than other parts of the intermediate groove bottom plate 31. The intermediate groove side plate 32 is also assembled by stacking multiple annular segments formed by arranging multiple side plate members in a circular shape. The intermediate groove side plate member 32P1 shown in FIG7 is the side plate member constituting the lowermost annular segment of the intermediate groove side plate 32. The intermediate groove side plate member 32P1 is erected vertically upward from the radially outer periphery of the intermediate groove wheel 311. The intermediate channel side plate 32P1 is also a side plate that makes the height of the second annular section of the intermediate channel side plate 32 consistent with the height of the lowest annular section of the inner channel side plate 42 constructed later.

[0032] <Step S6> Figure 8 shows the construction status of step S6. In step S6, the construction of the outer trough roof 23 continues, ultimately forming a roof connector 20 integrating three roofs. The outer trough side panels 22 are then installed to a predetermined height. Regarding the outer trough roof 23, the radially central outer trough roof component 23P installed in step S5 is connected to the pre-assembled outer trough roof blocks constructed on the ground, ultimately forming a dome-shaped outer trough roof 23. During this extension, the outer trough roof peripheral support 63 (second temporary support), including H-beams, is positioned appropriately between the intermediate trough roof 33 and the outer trough roof 23, and both are temporarily fixed.

[0033] At the point when the outer roof 23 is completed, the roof connector 20 is considered complete. Specifically, the roof connector 20 is formed as follows: the middle roof 33 is temporarily fixed to the inner roof 43 by the middle roof support 61, and the outer roof 23 is temporarily fixed to the middle roof 33 by the outer roof central support 62 and the outer roof peripheral supports 63. Through the formation of the roof connector 20 as described above, the three roofs can be air-floated as a single unit. Before air-floating, the supports 61, 62, and 63 serve as supporting components for the upper roof section, but after air-floating, they become suspension components for the lower roof section.

[0034] Furthermore, in the formed state of the roof connector 20, the gaps between the inner tank roof 43 and the middle tank roof 33, and between the middle tank roof 33 and the outer tank roof 23, are set to be slightly narrower than the gaps between the two in the completed triple-shell storage tank 1. This is to make it easier to perform the fixing operations of the inner tank roof 43 to the inner tank side plate 42 and the fixing operations of the middle tank roof 33 to the middle tank side plate 32 after air flotation.

[0035] Regarding the outer channel side plate 22, it is constructed by simply stacking a predetermined number of annular segments formed by the side plate members. In this way, the outer channel side plate 22 of a predetermined height is constructed around the roof connector 20, creating a state ready for air flotation. An outer perimeter corridor 27 is installed at the top 22T of the outer channel side plate 22. Furthermore, a portion of the second-level concrete layer 34 (omitted from the illustration) is poured onto the intermediate channel wheel 311, and then blocks forming the second ring 35 are laid.

[0036] <Step S7> Figure 9 shows the construction status of step S7. In step S7, the main preparation work for air flotation is carried out. To form a sealed space, sealing material 28 is installed on the outer perimeter 23E of the outer tank roof 23. The sealing material 28 seals the gap between the outer perimeter 23E and the inner surface of the outer tank side plate 22. On the outer side of the outer tank side plate 22, a blower 7 is prepared to supply air for air flotation. An air supply duct is connected to the air outlet of the blower 7, and the air supply duct is introduced into the inner side of the outer tank side plate 22 through the first opening OP1. In addition, the air supply duct is also sealed around the first opening OP1. The outer tank bottom plate 21 has been completed before step S7, so there is no need for sealing treatment of the bottom part. Therefore, at this point in time, the space surrounded by the outer tank bottom plate 21, the outer tank side plate 22 and the outer tank roof 23 is sealed.

[0037] In parallel with the above-mentioned air flotation preparation operation, an inner groove wheel 411 is installed on the upper surface of the second ring 35. The inner groove wheel 411 is the annular part near the outer periphery of the circular inner groove bottom plate 41.

[0038] <Step S8> Figure 10 shows the state after the air flotation is performed in step S8. During the air flotation, the blower 7 shown in Figure 9 operates, supplying air to the enclosed space surrounded by the outer tank bottom plate 21, the outer tank side plate 22, and the outer tank roof 23. As air is supplied, the air pressure in the aforementioned enclosed space rises, and the roof connector 20 floats up due to this pressure. At this time, the outer tank side plate 22 acts as a guide for the floated roof connector 20.

[0039] The outer roof 23 floats directly using air flotation. However, the inner roof 43 and the middle roof 33 are pre-integrated with the outer roof 23 via temporary supports 61, 62, and 63. Therefore, the inner roof 43 and the middle roof 33 also float as a single unit, suspended from the outer roof 23. That is, because the roof connector 20 is pre-formed, the three roofs 23, 33, and 43, forming a triple-shell structure, can float simultaneously using air flotation. Furthermore, during air flotation, a balance wire is used to control the buoyancy of the roof connector 20.

[0040] After air flotation, the outer perimeter 23E of the outer tank roof 23 is fixed to the upper end of the outer tank side plate 22. At this point, the temporary fixation of the roof connector 20 is not removed, and the inner tank roof 43 and the intermediate tank roof 33 are suspended from the outer tank roof 23. The air flotation equipment is removed. That is, the sealing material 28 installed near the outer perimeter 23E of the outer tank roof 23 is removed, and the blower 7 and air supply duct are removed.

[0041] <Step S9> Figure 11 shows the construction status of step S9. In step S9, the construction of the inner groove side plate 42 begins. The inner groove side plate 42 is also assembled by stacking multiple annular segments formed by arranging multiple side plate members in a circular shape. On the inner groove wheel 411, the inner groove side plate member 42P1 (side plate member) constituting the lowermost annular segment of the inner groove side plate 42 is installed. The inner groove side plate member 42P1 is erected vertically upward from the radially outer periphery of the inner groove wheel 411. Figure 11 shows the state in which the inner groove side plate member 42P2 constituting the second segment of the annular segment is installed on the lowermost inner groove side plate member 42P1.

[0042] During the construction of the inner tank side plate 42, a second opening OP2 is provided as an engineering opening. The second opening OP2 is created by removing one or more of the inner tank side plate members 42P1 that constitute the lowest annular section. The position of the second opening OP2 corresponds to the position of the first opening OP1 on the outer tank side plate 22. Specifically, the second opening OP2 and the first opening OP1 are located at approximately the same position in the circumferential direction of the triple-shell storage tank 1, and are also opened at approximately the same height. In this embodiment, the inner tank side plate member 42P1 and the second section outer tank side plate member 22P2 are located at approximately the same height. In the outer tank side plate 22, not only the lowest section outer tank side plate member 22P1, but also the second section outer tank side plate member 22P2 are removed, thereby making the second opening OP2 and the first opening OP1 have the same height.

[0043] <Step S10> Figure 12 shows the construction status of step S10. In step S10, the inner tank side plate 42 and the intermediate tank side plate 32 are constructed. Regarding the inner tank side plate 42, the inner tank side plate 42P3 constituting the third annular segment is installed on the inner tank side plate 42P2 constituting the second segment. Then, the inner tank side plate 42P4 constituting the fourth segment is installed on it, so that the height of the side plates increases sequentially.

[0044] Similarly, regarding the intermediate channel side plate 32, intermediate channel side plates 32P2, 32P3, and 32P4, forming the second, third, and fourth annular sections, are sequentially stacked on the lowest installed intermediate channel side plate 32P1. In this embodiment, the inner channel side plate 42Pn and the intermediate channel side plate 32Pn (except for the part 32P1 with the same height) have the same height range. Therefore, the inner channel side plates 42P1, 42P2, and 42P3 and the intermediate channel side plates 32P2, 32P3, and 32P4 shown in FIG12 are located at the same height position.

[0045] In step S10, the annular segments of either the inner groove side plate 42 or the intermediate groove side plate 32 can be stacked first, followed by the stacking of the other annular segment. However, it is preferable to stack the annular segments of the inner groove side plate 42 and the intermediate groove side plate 32 simultaneously and in parallel. For example, after stacking the inner groove side plate 42P2 of the second segment of the inner groove side plate 42, the intermediate groove side plate 32P3 of the third segment of the intermediate groove side plate 32 can be stacked, followed by the stacking of the inner groove side plate 42P3 of the third segment of the inner groove side plate 42. If the construction method described above is adopted, the inner groove side plate 42 and the intermediate groove side plate 32 can share a common foothold, etc., which can improve work efficiency. Furthermore, for the convenience of crane lifting or assembly operations of the side plate components, it is ideal to stack the inner groove side plate 42Pn located radially inward before stacking the intermediate groove side plate 32Pn.

[0046] During the construction of the intermediate channel side plate 32, a third opening OP3 is also provided as an engineering opening. The third opening OP3 is created by removing one or more pieces of the intermediate channel side plate 32P2 that constitute the annular section of the second segment. As marked as "open" in the diagram of Figure 2, at the time point of step S10, the second opening OP2 is opened in the inner channel side plate 42, and the third opening OP3 is opened in the intermediate channel side plate 32.

[0047] The third opening OP3 is positioned corresponding to the second opening OP2 of the inner tank side plate 42. Specifically, the second opening OP2 and the third opening OP3 are located at approximately the same circumferential position and at approximately the same height. As mentioned above, the second opening OP2 is located corresponding to the first opening OP1 of the outer tank side plate 22. Therefore, the first opening OP1, the second opening OP2, and the third opening OP3 are located at approximately the same circumferential and height positions. This allows for efficient movement of workers inside and outside the storage tank under construction, as well as the loading and unloading of materials or construction machinery.

[0048] In step S10, the first-level concrete layer 24 (not shown in Figure 12) and the outer bottom insulation layer 26 are then sequentially laid on the outer bottom plate 21. Since the first-level concrete layer 24 was partially completed on the outer groove wheel 211 in step S2, the remaining portion is constructed. As described above, the outer bottom insulation layer 26 is constructed by covering the inner side of the first ring portion 25 with insulating block materials such as foam glass.

[0049] <Step S11> Figure 13 shows the construction status of step S11. In step S11, the construction of the inner channel side plate 42 and the intermediate channel side plate 32 continues, the inner channel side plate 42 is fixed to the inner channel roof 43, and the intermediate channel bottom plate 31 is laid. Regarding the inner channel side plate 42 and the intermediate channel side plate 32, the upper section is installed from the middle section of their respective annular segments. Figure 13 shows the state in which the inner channel side plate 42 is assembled into the inner channel side plate component 42PT of the uppermost annular segment in a manner that is a step faster than that of the intermediate channel side plate 32.

[0050] The reason for assembling the annular section of the inner groove side plate 42 to the uppermost position before the middle groove side plate 32 is as follows. When lifting the side plates 32P and 42P, an "outer-side lifting" is performed by positioning the crane radially outward of the side plates. This is because each of the inner groove side plate 42 and the middle groove side plate 32 has an assembly fixture with a foothold on its inner surface, and an operator's entrance on its inner surface. If the middle groove side plate 32 is assembled first, lifting the inner groove side plate 42P will be difficult due to the foothold on its inner surface. Therefore, it is ideal to assemble the inner groove side plate 42 first, forming a foothold on the inner surface of the middle groove side plate 32, and then lift the middle groove side plate 32P from the outside.

[0051] After the inner channel side plate 42PT is installed at the top, the outer periphery of the inner channel roof 43 is fixed to the upper end of the inner channel side plate 42. Before this fixing operation, a suspension replacement operation is performed, that is, the intermediate channel roof support 61 connecting the intermediate channel roof 33 and the inner channel roof 43 is replaced with the first jack 64. After air flotation, with the temporary fixation of the roof connector 20 still in place and the outer channel roof 23 fixed to the outer channel side plate 22, the inner channel roof 43 is suspended from the intermediate channel roof 33 at a higher position than the normal height position by means of the intermediate channel roof support 61. The reason for this is to ensure adjustment space when connecting the inner channel roof 43 to the inner channel side plate 42.

[0052] The first jack 64 is positioned appropriately between the intermediate channel roof 33 and the inner channel roof 43. After the aforementioned suspension replacement, the inner channel roof 43 is suspended and supported in a liftable manner. While using the first jack 64, the inner channel roof 43 is lowered only to a degree corresponding to the aforementioned lowering adjustment space, and the lower end of the inner channel steering knuckle plate 44 is aligned with the upper end of the uppermost inner channel side plate 42PT. After alignment, both are fixed, and the inner channel 4 is substantially completed.

[0053] Then, in step S11, the remainder of the intermediate groove bottom plate 31 is laid on the outer bottom insulation layer 26. Regarding the intermediate groove bottom plate 31, since the intermediate groove wheel 311 constituting the outer periphery has been installed, the intermediate groove bottom plate 31 of its inner side is laid.

[0054] <Step S12> Figure 14 shows the construction status of step S12. In step S12, the intermediate channel side plate 32 and the intermediate channel roof 33 are fixed, and the inner bottom insulation layer 36 is laid. Similar to the inner channel roof 43, the intermediate channel roof 33 is also fixed by lowering it with jacks. After the inner channel roof 43 is fixed to the inner channel side plate 42, the intermediate channel side plate component 32PT, which constitutes the uppermost annular section of the intermediate channel side plate 32, is installed. On the other hand, a suspension replacement operation is performed, that is, the outer channel roof central support 62 and the outer channel roof peripheral support 63 that connect the outer channel roof 23 and the intermediate channel roof 33 are replaced with the second jack 65. The intermediate channel roof 33 is also suspended from the outer channel roof 23 at a position that is only slightly higher than the normal height position, corresponding to the aforementioned adjustment space.

[0055] The second jack 65 is positioned appropriately between the outer channel roof 23 and the intermediate channel roof 33. After the aforementioned suspension replacement, the intermediate channel roof 33 is suspended and supported in a liftable manner. While using the second jack 65, the intermediate channel roof 33 is lowered only to a degree corresponding to the aforementioned adjustment space, and the lower end of the intermediate channel steering knuckle plate 37 is aligned with the upper end of the uppermost intermediate channel roof component 33PT. After alignment, both are fixed, and the intermediate channel 3 is substantially completed.

[0056] In step S12, an inner bottom insulation layer 36 is then laid on the bottom plate 31 of the intermediate trough (second-level concrete layer 34). The inner bottom insulation layer 36 is constructed by covering the inner side of the second ring 35 with insulating block material such as foam glass.

[0057] <Step S13> Figure 15 shows the construction status of step S13. In step S13, the inner tank bottom plate 41 is laid, the second opening OP2 is sealed, and the platform is installed. The inner tank bottom plate 41 is laid on the inner bottom insulation layer 36. Regarding the inner tank bottom plate 41, since the inner groove wheel 411 constituting the outer periphery has been installed, the inner tank bottom plate 41 of its inner part is laid.

[0058] After the work on the inner side of the inner groove 4 is completed and the support structures and other fixtures located on the inner side of the inner groove 4 are removed, the second opening OP2 of the inner groove side plate 42 is sealed. This sealing operation involves inserting the inner groove side plate 42P1, which was pulled out from the lowest annular section in step S9, into the second opening OP2, and welding the inner groove side plate 42P1 to the surrounding side plates. Figure 15 shows the state in which the second opening OP2 is sealed.

[0059] A shoulder platform 231 and a top platform 232 are installed on the outer roof 23. The shoulder platform 231 is located on the radial outer periphery of the outer roof 23. The top platform 232 is located on the radial center of the outer roof 23. In addition, work is also carried out such as filling insulation material in the first compartment 11 and the second compartment 12, or installing various pipes or accessories.

[0060] <Step S14> Figure 16 shows the construction status of step S14. In step S14, the third opening OP3 and the first opening OP1 are sealed. After the work of the third opening OP3 of the intermediate groove side plate 32 being located inside the intermediate groove 3 is completed, the support and other parts set inside the intermediate groove 3 are removed and then sealed. In this sealing operation, the intermediate groove side plate 32P2 extracted in step S10 is inserted into the third opening OP3, and the intermediate groove side plate 32P2 is welded to the surrounding side plates.

[0061] Subsequently, after the work on the inner side of the outer groove 2 is completed and the support structures located on the inner side of the outer groove 2 are removed, the first opening OP1 of the outer groove side plate 22 is sealed. In this sealing operation, the outer groove side plates 22P1 and 22P2, which were removed in steps S2 and S3, are inserted to block the first opening OP1, and then welded. As described above, the openings are sealed sequentially after the work on each side plate is completed, in the order of the inner second opening OP2, the middle third opening OP3, and the outer first opening OP1.

[0062] [Effects] Using the construction method of the triple-shell storage tank disclosed above, a roof connector 20 is formed before air flotation, whereby the inner tank roof 43, the intermediate tank roof 33, and the outer tank roof 23 are temporarily fixed to each other. Specifically, the intermediate tank roof 33 is temporarily fixed to the inner tank roof 43 using the intermediate tank roof support 61, and the outer tank roof 23 is temporarily fixed to the intermediate tank roof 33 using the outer tank roof central support 62 and the outer tank roof peripheral support 63, thereby forming the roof connector 20. After forming the outer tank side plate 22, which serves as a buoyancy guide, around the roof connector 20, air flotation is performed on the roof connector 20.

[0063] Here, the outer trough roof 23 is directly air-floated, but the inner trough roof 43 and the intermediate trough roof 33 also float as a whole, maintaining their shape within the outer trough roof 23. In other words, while suspended from the outer trough roof 23, the inner trough roof 43 and the intermediate trough roof 33 also float. That is, the roofs of the three-shell structure are formed through the work on the ground foundation, and these are temporarily fixed and integrated, then floated up in one air-floating operation. Therefore, most of the construction work of the roofs of the three-shell structure and the construction work of the side panels can be carried out in parallel by working at a low level, thus helping to shorten the construction period. Furthermore, after fixing the outer trough roof 23 to the outer trough side panel 22 to form the outer trough 2, the inner trough side panel 42 and the intermediate trough side panel 32 can be constructed. That is, the construction work of the inner trough side panel 42 and the intermediate trough side panel 32 can be carried out in the space covered by the outer trough 2. Therefore, the above-mentioned construction work can be carried out without being affected by the weather, and it also has the advantage of avoiding the decline in welding quality caused by the presence of moisture.

[0064] [Modified Implementation] The above describes the implementation method of the construction method for the triple-shell storage tank disclosed herein, but this disclosure is not limited to the above implementation method in any way. For example, the construction method for the above triple-shell storage tank can be modified as follows.

[0065] (1) The necessary buildings or equipment may also be attached near the triple-shell storage tank 1. For example, a liquid-proof dike may be erected around the triple-shell storage tank 1 to suppress the spread of liquid leakage in the storage tank during disasters. The liquid-proof dike may be constructed using PC (prestressed concrete). The liquid-proof dike may also be constructed integrally with the metal outer tank 2. Specifically, it may be constructed in a manner in which PC constituting the liquid-proof dike is closely connected to the outer periphery of the outer tank side plate 22. In this case, the strength of the outer tank side plate 22, which serves as a guide during the air flotation of the roof connector 20, can be improved.

[0066] (2) Various structures can also be added to reinforce the strength of the triple-shell storage tank 1. For example, it can also have anchors that connect the intermediate tank side plate 32 and / or the inner tank side plate 42 to the storage tank foundation 10.

[0067] (3) Alternatively, a connecting pipe can be installed on the roof 43 of the inner tank to connect the internal space of the inner tank 4 with the space of the first tank 11. According to this modified example, hydrogen gas generated from the vaporization of liquid hydrogen LH stored in the inner tank 4 can circulate in the first tank 11. That is, the stored liquid hydrogen LH can be used to improve the cooling effect.

[0068] (4) In the above embodiment, an example is shown in which the first opening OP1, the second opening OP2 and the third opening OP3 are opened at the same position in the circumferential direction of the triple-shell storage tank 1 at approximately the same height. These openings OP1, OP2 and OP3 may be opened at different positions in the circumferential direction of the triple-shell storage tank 1, or at different heights.

[0069] [Summary of this disclosure] The specific embodiments described above include disclosures of having the following configurations.

[0070] The construction method of the triple-shell storage tank disclosed herein includes the construction of an inner tank, a middle tank, and an outer tank, each having a roof and side panels. This method involves temporarily fixing the middle tank roof to the inner tank roof, and then temporarily fixing the outer tank roof to the middle tank roof to form a roof connector. A side panel of a predetermined height is constructed around the roof connector. A sealed space is formed between the outer perimeter of the outer tank roof and the inner surface of the side panel, and air is supplied to this sealed space to aerate the roof connector. The outer tank roof and the outer tank side panels are then fixed. The inner tank side panels and the middle tank side panels are constructed. The temporary fixing of the roof connector is released, and the inner tank roof and the inner tank side panels are fixed. Finally, the middle tank roof and the middle tank side panels are fixed.

[0071] According to this construction method, before air flotation, a roof connection is formed that temporarily fixes the inner, middle, and outer roofs together. Then, after forming outer side panels around the roof connection, the roof connection is air-floated. The outer roof is directly air-floated, but the inner and middle roofs also float as a whole, maintaining their shape relative to the outer roof. That is, the roofs of the three shells are formed through ground-level work, and these temporary fixations are integrated, allowing them to float simultaneously in a single air flotation operation. Therefore, most of the construction work for the three shell roofs can be performed at low altitudes, thus helping to shorten the construction period. Furthermore, after fixing the outer roof to the outer side panels to form the outer trench, the inner and middle side panels are constructed. That is, the construction work for the inner and middle side panels can be carried out while the outer trench is covered, thus also having the advantage of being unaffected by weather.

[0072] In the construction method of the above-mentioned triple-shell storage tank, ideally, the bottom plate of the outer tank, which constitutes the bottom of the area surrounded by the outer tank side plate, is formed at least before the above-mentioned air flotation.

[0073] According to this construction method, by pre-forming the bottom plate of the outer tank, it is easier to form the closed space required for air flotation.

[0074] In the construction method of the above-mentioned triple-shell storage tank, ideally, after the outer tank bottom plate is formed, a roof platform is set on the outer tank bottom plate; the inner tank roof is installed on the roof platform, and a first temporary support is set on the inner tank roof; the intermediate tank roof is installed on the first temporary support, and a second temporary support is set on the intermediate tank roof; the roof connector is formed by installing the outer tank roof on the second temporary support.

[0075] According to this construction method, a roof connection is formed by sequentially installing the intermediate roof and the outer roof on the innermost inner roof. Therefore, the aforementioned roof connection can be formed with high efficiency.

[0076] In the construction method of the above-mentioned triple-shell storage tank, ideally, the inner tank side plate and the middle tank side plate are assembled by stacking multiple annular segments formed by arranging multiple side plate pieces in a circular shape, and the annular segments of the inner tank side plate and the annular segments of the middle tank side plate are stacked in parallel.

[0077] According to this construction method, when constructing the inner tank side plate and the middle tank side plate, for example, a common footing can be used, which can improve the efficiency of the operation and thus help to shorten the construction period.

[0078] In the construction method of the above-mentioned triple-shell storage tank, ideally, the inner tank side plate and the middle tank side plate are assembled by stacking multiple annular segments formed by arranging multiple side plate pieces in a circular shape, and the annular segment of the inner tank side plate is assembled to the uppermost position before the middle tank side plate, and the annular segment of the uppermost position and the outer perimeter of the inner tank roof are fixed.

[0079] According to this construction method, since the roof and side panels of the inner channel, which are located further inside the middle channel, are fixed first, the workability is better compared to fixing the roof and side panels of the middle channel first.

[0080] In the construction method of the above-mentioned triple-shell storage tank, ideally, when constructing the outer tank side plate, the engineering inlet, i.e., the first engineering port, is opened on the outer tank side plate; when constructing the inner tank side plate, the second engineering port is opened on the inner tank side plate; and when constructing the intermediate tank side plate, the third engineering port is opened on the intermediate tank side plate. After the work on the inner side of the inner tank is completed, the second engineering port is sealed. Then, after the work on the inner side of the intermediate tank is completed, the third engineering port is sealed. Finally, after the work on the inner side of the outer tank is completed, the first engineering port is sealed.

[0081] According to this construction method, the engineering opening can be made in a timely manner on each of the outer tank side plate, the middle tank side plate and the inner tank side plate, so that various projects can proceed smoothly.

[0082] 1: Triple-shell storage tank 2: Outer groove 3: Intermediate groove 4: Inner groove 7: Blower 10: Storage tank foundation 11: First tank 12: Second tank 20: Roof Connector 21: Outer groove bottom plate 22: Outer groove side plate 22P1, 22P2, 22P3, 22P4: Outer groove side plate parts 22T: Top 23: External roof 23E: Peripheral edge 23P: External channel roof component 24: Grade 1 concrete layer 25: First Ring Section 26: Outer bottom insulation layer 27: Outer Corridor 28: Sealing materials 31: Intermediate groove bottom plate 32: Intermediate groove side plate 32P1, 32P2, 32P3, 32P4, 32Pn, 32PT: Intermediate slot side plate components 33: Intermediate trough roof 33E: Peripheral edge 33P, 33PT: Intermediate channel roof components 34: Second-grade concrete layer 35: Second Ring Section 36: Inner bottom insulation layer 37: Intermediate slot steering knuckle plate 41: Inner groove bottom plate 42: Inner groove side plate 42P1, 42P2, 42P3, 42P4, 42Pn, 42PT: Inner groove side plate parts 43: Inner groove roof 43E: Peripheral edge 43P: Inner channel roof component 44: Inner groove steering knuckle plate 51: Central roof platform 52: Outer perimeter roof platform 61: Intermediate channel roof support 62: Central support for the outer roof trough 63: Peripheral support frame for the outer roof channel 64: The first jack 65: The 2nd Jack 211: Outer Grooved Wheel 231: Shoulder Platform 232: Top Platform 251: Reinforced concrete layer 311: Intermediate Grooved Wheel 351: Reinforced concrete layer 411: Inner Grooved Wheel LH: Liquid hydrogen OP1: First opening OP2: Second opening OP3: Third opening RC: Radial center S1~S14: Steps

Claims

1. A construction method for a triple-shell storage tank, comprising an inner tank, a middle tank, and an outer tank each having a roof and side panels, wherein a roof connector is formed by temporarily fixing a middle tank roof to the inner tank roof and then temporarily fixing an outer tank roof to the middle tank roof; an outer tank side panel of a predetermined height is constructed around the roof connector; a sealed space is formed between the outer periphery of the outer tank roof and the inner surface of the outer tank side panel, and air is supplied to the sealed space to aerate the roof connector; the outer tank roof and the outer tank side panel are fixed; the inner tank side panel and the middle tank side panel are constructed; the temporary fixing of the roof connector is released; the inner tank roof and the inner tank side panel are fixed; and the middle tank roof and the middle tank side panel are fixed.

2. The construction method of the triple-shell storage tank as claimed in claim 1, wherein at least before the aforementioned air flotation, an outer tank bottom plate constituting the bottom of the area surrounded by the aforementioned outer tank side plates is formed.

3. The construction method of the triple-shell storage tank as claimed in claim 2, wherein after the outer tank bottom plate is formed, a roof platform is provided on the outer tank bottom plate; the inner tank roof is installed on the roof platform, and a first temporary support is provided on the inner tank roof; the intermediate tank roof is installed on the first temporary support, and a second temporary support is provided on the intermediate tank roof; the roof connector is formed by installing the outer tank roof on the second temporary support.

4. The construction method of the triple-shell storage tank according to any one of claims 1 to 3, wherein the inner tank side plate and the intermediate tank side plate are assembled by stacking a plurality of annular segments formed by arranging a plurality of side plate pieces in a circular shape, and the annular segments of the inner tank side plate and the annular segments of the intermediate tank side plate are stacked in parallel.

5. The construction method of the triple-shell storage tank according to any one of claims 1 to 3, wherein the inner tank side plate and the middle tank side plate are assembled by stacking multiple segments of annular segments formed by arranging a plurality of side plate pieces in a circular shape, and the annular segment of the inner tank side plate is assembled to the uppermost segment before the middle tank side plate, and the annular segment of the uppermost segment and the outer perimeter of the inner tank roof are fixed.

6. The construction method of the triple-shell storage tank as claimed in any of claims 1 to 3, wherein during the construction of the outer tank side plate, the engineering inlet / outlet, i.e., the first engineering port, is opened on the outer tank side plate; during the construction of the inner tank side plate, a second engineering port is opened on the inner tank side plate, and during the construction of the intermediate tank side plate, a third engineering port is opened on the intermediate tank side plate; after the work on the inner side of the inner tank is completed, the second engineering port is sealed; then after the work on the inner side of the intermediate tank is completed, the third engineering port is sealed; and then after the work on the inner side of the outer tank is completed, the first engineering port is sealed.

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