Corner connecting structure of LNG (Liquefied Natural Gas) film tank

Abstract

The invention relates to a corner connecting structure of an LNG film tank. The corner connecting structure comprises a concrete outer tank; the perlite concrete layer is connected with the concrete outer tank; the polyurethane foam layer is connected with the perlite concrete layer; the insulating block is connected with the polyurethane foam layer; the bearing plates are located on the vertical side and the horizontal side respectively and connected with the insulating block, and each bearing plate bears a corrugated plate; the arc-shaped L-shaped corner plate is positioned between the two bearing plates on the vertical side and the horizontal side; and the corrugated end socket is connected with the end part, adjacent to the corner plate, of the corrugated plate and is welded on the corner plate. The corner plates are designed, the size of the corner plates is larger than that of stainless steel connecting pieces in the prior art, therefore, the large-size corner plates replace small-size stainless steel connecting pieces, the corner plates form the annular bearing platform with the closed corner areas in a welding mode, gaps between the corner plates are avoided, and the bearing platform is convenient to assemble and disassemble. And the risk of integral leakage of the corner area caused by damage of the corrugated plate is reduced.

Description

Technical Field

[0001] The present invention belongs to the fields of LNG storage and oil and gas storage and transportation, and more specifically, the present invention relates to a corner connection structure of an LNG membrane tank. Background Art

[0002] In recent years, with the change of the international energy pattern and the gradual strengthening of environmental protection awareness, the demand for natural gas in China has shown a steady upward trend. Group companies, pipeline bureaus, and pipeline design institutes are all actively promoting the development of natural gas storage and transportation business. Accelerating the development of the natural gas industry and increasing the proportion of natural gas in primary energy consumption is the only way for China to build a clean, low-carbon, safe, and efficient modern energy system, and it is also an effective way to achieve green and low-carbon development. At the same time, it is of great significance to promote energy conservation and emission reduction, stable growth, people's livelihood improvement, and development promotion.

[0003] LNG (liquefied natural gas) storage tanks, as indispensable storage facilities in the LNG industrial chain, are also the key links with the highest construction investment, the longest construction period, the most advanced technology, and the most difficulties in the construction of LNG receiving stations. The technological development of LNG storage tanks has attracted much attention. At present, LNG storage tanks show a trend of large-scale development, and the advantages of membrane tanks are gradually emerging. It has the advantages of high storage efficiency, high comprehensive land utilization rate, low single-volume construction cost, and no upper limit on the storage tank volume. At present, the typical structure of a membrane tank mainly consists of a prestressed concrete outer tank, a membrane inner tank, an insulation system, and other accessories. Among them, the corner area connecting the inner tank wall and the tank bottom is the key to the construction of the membrane tank, and it is also one of the areas where heat leakage and structural damage are most likely to occur in the membrane tank. At the same time, limited by the spatial position of the corner area, the construction of the corner area is more difficult than that of the tank wall and the tank bottom, and the welding operation technology requirements are higher. The corner area is also the area with the largest theoretical deformation of the membrane tank. Therefore, how to ensure the structural strength and good heat insulation effect of the corner area has become the key to the construction of the membrane tank.

[0004] Early membrane systems were applied to marine gas carriers, especially LNG carriers. In 1972, GTT of France first applied stainless steel membranes to two onshore liquid ethylene storage tanks in France in a land-based storage tank system. After that, it continuously developed the system and built two 120,000-cubic-meter onshore LNG storage tanks for Gaz de France in Montivilliers, Brittany in 1980. Subsequently, between 1986 and 1998, 10 onshore LNG storage tanks with a volume of 100,000 cubic meters were built in Pyeongtaek, South Korea.

[0005] After introducing the GTT membrane technology of France, Japan and South Korea respectively developed their own membrane tank design and construction technologies. At present, NKK, MHI, IHI, and KHI in Japan and KOGAS in South Korea have all designed and built LNG membrane tanks with independent intellectual property rights and have been put into production and operation so far.

[0006] At present, there are about 100 thin-film tanks built and put into operation globally. Among them, there are about 67 underground thin-film tanks, 33 above-ground thin-film tanks have been built, and 4 are under construction. The largest above-ground thin-film tank has a volume of 100,000 cubic meters and uses the thin-film technology provided by GTT. The largest underground thin-film tank has a volume of 270,000 cubic meters and uses the thin-film technology of KOGAS in South Korea. Currently, the largest above-ground and underground LNG thin-film tanks in operation abroad are both located in South Korea.

[0007] In contrast, the construction of thin-film tanks in China started relatively late and is in the stage of theoretical research and introduction. Currently, Beijing Gas Group's Tianjin Nangang LNG Terminal is building 8 thin-film tanks with a volume of 220,000 cubic meters each. The 2 already-built ones are expected to be put into operation by the end of 2023. CNPC has built and put into operation a 29,000-cubic-meter LNG thin-film tank at the Hejian LNG peak-shaving station, both using the thin-film tank technology of French company GTT.

[0008] Based on the above research, it can be known that the thin-film tank technology worldwide currently originates from French company GTT, and the technology introduced and digested in China is also that of French GTT. Therefore, this invention takes the design and construction technology of French GTT as an example to conduct a technical comparison. The thickness of the corrugated plate of French GTT is 1.2 mm, and the corrugation pitch is 560 mm × 650 mm. The corrugations are continuous, divided into large and small corrugations. The intersection of the corrugations is in a wrinkled shape. The corrugated plates are connected by lap welding. This corrugated plate is mainly used for the laying of the tank wall and the tank bottom to form a sealed space and provide the shrinkage deformation amount caused by temperature changes.

[0009] However, for the thin-film tank of French GTT, in the corner area, in order to maintain the sealed space of the inner tank, it uses corner-sealing corrugated connectors to connect the raised corrugations of the tank wall and the tank bottom and weld them together with the bottom stainless-steel corner connectors. The flat edges of the corrugated plates are directly welded to the stainless-steel corner connectors. Therefore, limited by the spacing size of the corrugated plate of 560 mm × 650 mm, the size of its stainless-steel connectors also needs to be maintained at 560 mm or 650 mm. There is a certain gap between the stainless-steel connectors to avoid damaging the weld of the corrugated connectors due to cold shrinkage. This gap is exactly located below the corner-sealing corrugated connectors. The above-mentioned stainless-steel connectors are only fixed to the plywood on the back, so they do not have the ability to bear radial and axial loads. All deformations are borne by the raised corrugations on the corrugated plates.

[0010] The above-mentioned corner connection structure of the GTT thin-film tank has relatively high requirements for the installation accuracy of the corrugated plates of the tank wall and the tank bottom. Therefore, scribing operations need to be carried out before installing the corrugated plates, which increases the construction difficulty. It is generally difficult for technicians without professional training to be competent for this work. Through on-site research, it can be known that almost all GTT patented technologies were adopted during the construction of the LNG thin-film tank in Beiran Tianjin Nangang, resulting in the failure to reflect the cost advantage of the thin-film tank. Therefore, for the design and construction of thin-film tanks, it is urgent to overcome related technical problems and accelerate the localization process of thin-film tank design and construction.

[0011] It can be seen from this that domestic LNG storage tanks still mainly use concrete full containment tanks, and the construction of thin-film tanks has just started. All the built or under-construction LNG thin-film tanks adopt foreign patented technologies, and are subject to others from design to procurement, processing, and construction. Therefore, the domestic LNG storage tank construction mainly faces the following problems:

[0012] (1) Domestic LNG storage tanks mainly use concrete full containment tanks, and the technology is relatively mature. However, as the volume of the storage tank gradually increases, the cost advantage of concrete full containment tanks is no longer obvious, and restricted by the internal tank steel and seismic design, the concrete full containment tank can theoretically only reach 270,000 cubic meters, which cannot meet the large-scale development trend of LNG storage tanks.

[0013] (2) In theory, thin-film tanks can be unrestricted by volume, and the construction cost per unit volume decreases as the tank volume increases. However, at present, domestic capabilities for the design and construction of thin-film tanks are lacking, mainly reflected in the fact that the design and analysis technologies of thin-film tanks have not been mastered, and domestic manufacturers do not have the production qualifications and production capabilities for main components such as corrugated plates and insulation layers.

[0014] (3) One of the cores of thin-film tanks is the internal tank thin-film corrugated plate, which mainly functions to form a sealed space. At present, this technology is mainly monopolized by companies such as French GTT, South Korean KOGAS, and Japanese IHI, resulting in the high construction cost of thin-film tanks and the inability to meet the construction needs of the domestic market. Taking the thin-film tank technology of French GTT company as an example, since all deformations of its internal tank are borne by the corrugated plates, the construction of the internal tank corner area is relatively cumbersome, and special corner corrugated connectors are required for sealing. Overall, the corner area shows a small-size block splicing form, which puts higher requirements on the installation accuracy of the corrugated plates of the tank wall and the tank bottom. At the same time, there are spacing gaps between small-size stainless steel connectors. Once the sealing corrugated connectors are damaged or leaked, it will leak along the gap to the tank bottom, posing a major hidden danger to the safety of the entire storage tank.

[0015] Therefore, the existing technology needs to be improved. Summary of the Invention

[0016] The object of the present invention is to provide a corner connection structure for a large LNG membrane tank, so as to simplify the construction process of the inner tank corner area and improve the overall strength and heat insulation effect of the corner area. The corner connection structure provided by the present invention has the advantages of simple configuration, convenient construction, easy guarantee of strength, and good heat insulation effect, which will effectively replace the original structure, greatly simplify the on-site construction process, improve the construction quality, and is of great significance for promoting the localization process of LNG membrane tanks.

[0017] In order to solve the above technical problems or achieve the above object, the present invention adopts the following specific technical solutions:

[0018] According to an aspect of the present invention, there is provided a corner connection structure for an LNG membrane tank, comprising:

[0019] A concrete outer tank, on the inner side of which there are successively connected a perlite concrete layer, a polyurethane foam layer and an insulating block;

[0020] Load-bearing plates respectively located on the vertical side and the horizontal side of the corner area, each load-bearing plate is connected to the insulating block, each load-bearing plate has a first part and a second part connected to the end of the first part, and a corrugated plate is carried on each load-bearing plate;

[0021] A corner plate, which is in an arc-shaped L shape, the corner plate is positioned between the load-bearing plate on the vertical side and the load-bearing plate on the horizontal side, the vertical part of the corner plate is connected above the second part of the load-bearing plate on the vertical side and connected to the first part, the horizontal part of the corner plate is connected above the second part of the load-bearing plate on the horizontal side and connected to the first part, and the arc-shaped part of the corner plate is connected to the insulating block;

[0022] A corrugated head, which is connected to the end of the corrugated plate adjacent to the corner plate and welded to the corner plate.

[0023] In an embodiment of the present invention, the corner connection structure further comprises:

[0024] Anchoring and strengthening members respectively located on the vertical side and the horizontal side of the corner area, each anchoring and strengthening member includes a strengthening plate, a first embedded plate, a connecting member and a second embedded plate, the strengthening plate is fixed in the perlite concrete layer, the first embedded plate is positioned in the perlite concrete layer and under the strengthening plate, the second embedded plate is positioned in the second part of the bearing plate and is welded and fixed to the corner plate through a welding hole on the corner plate, and the connecting member connects the first embedded plate and passes through the strengthening plate to connect to the second embedded plate.

[0025] In an embodiment of the present invention, the corner connection structure further comprises:

[0026] An anchoring connecting member, which includes an anchoring stud, an anchoring nut and an insulating plug, the anchoring stud is inserted into the hole and fastened by the anchoring nut and the hole is filled with the insulating plug.

[0027] In one embodiment of the present invention, the perlite concrete layer is fixedly connected to the concrete outer tank through anchor connectors; the polyurethane foam layer is fixedly connected to the perlite concrete layer through anchor connectors.

[0028] In one embodiment of the present invention, the density of the perlite concrete layer is 1000 kg / m 3 , the thermal conductivity is not higher than 0.22 W / (m·K), and the average compressive strength is not less than 6.0 MPa.

[0029] In one embodiment of the present invention, the perlite concrete layer is prefabricated into blocks in advance, with a thickness of 200 - 500 mm, and holes for installing anchor studs are reserved during prefabrication.

[0030] In one embodiment of the present invention, the thickness of the polyurethane foam layer is 200 - 400 mm.

[0031] In one embodiment of the present invention, the polyurethane foam layer is obtained through prefabrication and on-site spraying, and holes for installing anchor studs are reserved during prefabrication.

[0032] In one embodiment of the present invention, the polyurethane foam layer and the perlite concrete layer are laid with staggered joints.

[0033] In one embodiment of the present invention, the thickness of the insulating block is 50 - 200 mm.

[0034] In one embodiment of the present invention, the insulating block is connected to the polyurethane foam layer by means of glue bonding.

[0035] In one embodiment of the present invention, the insulating block and the polyurethane foam layer are installed with staggered joints.

[0036] In one embodiment of the present invention, the material of the insulating block is polyurethane foam or glass fiber.

[0037] In one embodiment of the present invention, the thickness of the bearing plate is 10 - 100 mm, and the material of the bearing plate is plywood or polytetrafluoroethylene plate.

[0038] In one embodiment of the present invention, the bearing plate is connected to the insulating block by means of glue bonding, and an installation gap is reserved between the bearing plates and the gap is kept consistent with the gap on the insulating block.

[0039] In one embodiment of the present invention, the corrugated plate is made of stainless steel plate or 9% nickel steel plate, and the thickness of the corrugated plate is 0.8 - 3 mm.

[0040] In one embodiment of the present invention, the number of corrugated plates is multiple, and the corrugated plates are connected in a lap welding form.

[0041] In one embodiment of the present invention, the thickness of the corner plate is 6 - 20 mm, and the length is 1500 - 2000 mm.

[0042] In one embodiment of the present invention, both the first embedded plate and the second embedded plate are made of stainless steel plate or 9% nickel steel plate. The diameter of the connecting rod is 8 - 20 mm, and the length is 600 - 1200 mm.

[0043] In one embodiment of the present invention, the material of the anchor stud is carbon steel or 9% nickel steel. The length of the anchor stud is 200 - 500 mm, and the diameter is 8 - 20 mm.

[0044] In one embodiment of the present invention, the material of the reinforcing plate is carbon steel or 9% nickel steel, and the thickness is 5 - 10 mm.

[0045] By adopting the above technical solutions, the present invention has the following advantages compared with the prior art:

[0046] (1) By studying the tensile characteristics of stainless steel materials and the elongation rate under low-temperature environments, and using theoretical analysis and numerical calculation methods, the present invention determines a design method using large-size corner plates as the bearing foundation, replacing the original corner-sealed corrugated connectors, reducing the design and processing difficulties of corrugated plates, while reducing the number of welds of the corrugated plates in the corner area and optimizing the welding operation space in the corner area.

[0047] (2) The large-size corner plates of the present invention replace the small-size stainless steel connectors. The corner plates are welded to form a closed annular bearing platform in the corner area, avoiding the existence of gaps between the corner plates and reducing the risk of overall leakage in the corner area caused by corrugated plate failure. The large-size corner plates are welded and anchored through embedded plates, improving the overall strength of the connectors. With the support of theoretical analysis and numerical calculation, using the self-strength and tensile characteristics of the corner plates, they can withstand the local stress and deformation caused by temperature changes, improving the overall safety of the inner tank.

[0048] (3) Between the concrete outer tank and the corrugated plates of the inner tank, the present invention creatively proposes a combined heat-insulating and heat-preserving method of perlite concrete layer + high-strength polyurethane foam layer. While ensuring the heat-insulating and heat-preserving effect, it provides a foundation for the anchoring of steel embedded parts. The steel embedded parts are fixed in the perlite concrete layer, which has high connection strength on the one hand and can effectively reduce the heat transfer and heat leakage of LNG through the steel embedded parts on the other hand.

[0049] (4) The way of welding connection between the corner plate and the corrugated head of the present invention replaces the original way of directly welding the corner sealing corrugated connecting piece to the corrugated plates of the tank wall and the tank bottom. Under the condition of the same tank volume and the same configuration of the corrugated plates, the weld length of the corrugated plates in the corner area is reduced by about 10%, and the installation accuracy of the corrugated plates of the tank wall and the tank bottom does not need to be considered, which is of great significance for improving the construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other embodiments can be obtained based on these drawings.

[0051] Figure 1 FIG. shows a three-dimensional structural schematic diagram of a corner connection structure of an LNG thin-film tank provided by the present invention;

[0052] Figure 2 FIG. shows a sectional view of a corner connection structure of an LNG thin-film tank provided by the invention.

[0053] LIST OF REFERENCE NUMERALS

[0054] 1 Concrete outer tank, 2 Perlite concrete layer, 3 Polyurethane foam layer, 4 Insulating block, 5 Bearing plate, 51 First part, 52 Second part, 6 Corrugated plate, 7 Corrugated head, 8 Welding hole, 9 Corner plate, 10 First embedded plate, 11 Connecting piece, 12 Insulating plug, 13 Anchor stud, 14 Reinforcing plate, 15 Second embedded plate, 16 Anchor nut. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0055] It should be understood that the embodiments of the present invention shown in the exemplary embodiments are merely illustrative. Although only a few embodiments of the present invention are described in detail, those skilled in the art can easily understand that various modifications are feasible without substantially departing from the teachings of the subject matter of the present invention. Accordingly, all such modifications should be included within the scope of the present invention. Without departing from the gist of the present invention, other substitutions, modifications, changes and deletions can be made to the design, operating conditions and parameters of the following exemplary embodiments.

[0056] As Figure 1-2 shown, a corner connection structure of an LNG thin-film tank provided by the present invention includes:

[0057] Concrete outer tank 1;

[0058] Perlite concrete layer 2, which is fixedly connected to the concrete outer tank 1;

[0059] A polyurethane foam layer 3, which is fixedly connected to the perlite concrete layer 2;

[0060] An insulating block 4, which is connected to the polyurethane foam layer 3;

[0061] Load-bearing plates 5 respectively located on the vertical side and the horizontal side of the corner area. Each load-bearing plate 5 is connected to the insulating block 4. Each load-bearing plate 5 has a first part 51 and a second part 52 connected to the end of the first part 51. A corrugated plate 6 is carried on each load-bearing plate 5;

[0062] A corner plate 9, which is arc-shaped L-shaped. The corner plate 9 is positioned between the load-bearing plate 5 on the vertical side and the load-bearing plate 5 on the horizontal side. The vertical part of the corner plate 9 is connected above the second part 52 of the load-bearing plate 5 on the vertical side and connected to the first part 51. The horizontal part of the corner plate is connected above the second part 52 of the load-bearing plate 5 on the horizontal side and connected to the first part 51. The arc-shaped part of the corner plate 9 is connected to the insulating block 4;

[0063] A corrugated head 7, which is connected to the end of the corrugated plate 6 adjacent to the corner plate 9 and welded to the corner plate 9.

[0064] Through the above technical solutions of the present invention, a corner plate is designed in the present invention. The corner plate has a larger size compared to the stainless steel connectors in the prior art. Thus, the large-size corner plates in the present invention replace the small-size stainless steel connectors. The corner plates form a closed annular bearing platform in the corner area through welding, avoiding the existence of gaps between the corner plates and reducing the risk of overall leakage in the corner area caused by the damage of the corrugated plate; between the concrete outer tank and the inner tank corrugated plate in the present invention, a combined heat insulation and thermal insulation method of perlite concrete layer + high-strength polyurethane foam layer is creatively proposed, providing a basis for the anchoring of steel embedded parts while ensuring the heat insulation and thermal insulation effect; the welding connection method of the corner plate and the corrugated head in the present invention replaces the original direct welding method of the corner sealing corrugated connector with the tank wall and the bottom corrugated plate of the tank. Under the condition of the same tank volume and the same corrugated plate configuration, the weld length of the corrugated plate in the corner area is reduced by about 10%, and the installation accuracy of the tank wall and the bottom corrugated plate does not need to be considered, which is of great significance for improving the construction efficiency.

[0065] In the above structure, such as Figure 2As shown in the figure, the corner connection structure further includes: anchoring and strengthening members respectively located on the vertical side and the horizontal side of the corner area. Each anchoring and strengthening member includes a strengthening plate 14, a first embedded plate 10, a connecting member 11, and a second embedded plate 15. The strengthening plate 14 is fixed in the perlite concrete layer 2. The first embedded plate 10 is positioned in the perlite concrete layer 2 and under the strengthening plate 14. The second embedded plate 15 is positioned in the second part 52 of the bearing plate 5 and is welded and fixed to the corner plate 9 through the welding holes 8 on the corner plate 9. The connecting member 11 connects the first embedded plate 10 and passes through the strengthening plate 14 to connect to the second embedded plate 15.

[0066] In the above structure, as Figure 2 shown, the corner connection structure further includes:

[0067] Anchoring connecting members, which include anchoring studs 13, anchoring nuts 16, and insulating plugs 12. The anchoring studs 13 are inserted into the holes and fastened by the anchoring nuts 16, and the insulating plugs 12 are filled in the holes.

[0068] In the above structure, the perlite concrete layer 2 is fixedly connected to the concrete outer tank 1 through the anchoring connecting members; the polyurethane foam layer 3 is fixedly connected to the perlite concrete layer 2 through the anchoring connecting members.

[0069] In the above structure, the density of the perlite concrete layer 2 is 1000 kg / m 3 , the thermal conductivity is not higher than 0.22 W / (m·K), and the average compressive strength is not less than 6.0 MPa.

[0070] In the above structure, the perlite concrete layer 2 is prefabricated into blocks in advance, with a thickness of 200 - 500 mm, and holes for installing the anchoring studs 13 are reserved during prefabrication.

[0071] In the above structure, the thickness of the polyurethane foam layer 3 is 200 - 400 mm.

[0072] In the above structure, the polyurethane foam layer 3 is obtained by prefabrication and on-site spraying, and holes for installing the anchoring studs 13 are reserved during prefabrication.

[0073] In the above structure, the polyurethane foam layer 3 and the perlite concrete layer 2 are laid with staggered joints.

[0074] In the above structure, the thickness of the insulating block 4 is 50 - 200 mm.

[0075] In the above structure, the insulating block 4 is connected to the polyurethane foam layer 3 by means of glue bonding.

[0076] In the above structure, the insulating block 4 and the polyurethane foam layer 3 are installed with staggered joints.

[0077] In the above structure, the insulating block 4 is made of polyurethane foam or glass fiber.

[0078] In the above structure, the thickness of the bearing plate 5 is 10 - 100 mm, and the bearing plate 5 is made of plywood or polytetrafluoroethylene plate.

[0079] In the above structure, the bearing plate 5 is connected to the insulating block 4 by means of glue bonding, and an installation gap is reserved between the bearing plates 5 and the gap is consistent with the gap on the insulating block.

[0080] In the above structure, the corrugated plate 6 is made of stainless steel plate or 9% nickel steel plate, and the thickness of the corrugated plate 6 is 0.8 - 3 mm.

[0081] In the above structure, the number of the corrugated plates 6 is multiple, and the corrugated plates 6 are connected in a lap welding form.

[0082] In the above structure, the thickness of the corner plate 9 is 6 - 20 mm, and the length is 1500 - 2000 mm.

[0083] In the above structure, both the first embedded plate 10 and the second embedded plate 15 are made of stainless steel plate or 9% nickel steel plate, the diameter of the connecting rod 11 is 8 - 20 mm, and the length is 600 - 1200 mm.

[0084] In the above structure, the material of the anchor stud 13 is carbon steel or 9% nickel steel, the length of the anchor stud 13 is 200 - 500 mm, and the diameter is 8 - 20 mm.

[0085] In the above structure, the material of the reinforcing plate 14 is carbon steel or 9% nickel steel, and the thickness is 5 - 10 mm.

[0086] The above technical solutions of the present invention will be described in detail below through specific embodiments.

[0087] In the embodiment of the present invention, a corner connection structure for a large LNG thin-film tank is proposed, which is mainly used for the construction of the corner area of the thin-film tank. It has the advantages of simple configuration, convenient construction, easy guarantee of strength, good heat insulation and heat preservation effect, etc. It will effectively replace the original structure, greatly simplify the on-site construction process, improve the construction quality, and provide technical support for the localization of the thin-film tank.

[0088] The corner connection structure designed in the embodiment of the present invention mainly consists of three parts: an adiabatic and heat-insulating layer, a corner sealing structure, and an anchoring and strengthening member. The adiabatic and heat-insulating layer mainly plays a role in supporting and heat preservation, and at the same time provides a foundation for the anchoring of steel embedded parts; the corner sealing structure is the core component of the corner connecting piece, providing a connecting bearing platform for the overall sealing of the inner tank; the anchoring and strengthening member is the connecting component between the adiabatic and heat-insulating layer and the corner sealing structure, and plays an important role in strengthening the strength and stability of the entire corner sealing structure.

[0089] As Figure 1-2 shown, the adiabatic insulation layer in the embodiment of the present invention mainly consists of a perlite concrete layer 2, a high-strength polyurethane foam layer 3, insulating blocks 4, and a bearing plate 5 composed of a first part 51 and a second part 52. Among them, the perlite concrete layer 2 is adjacent to the concrete outer tank 1 and is reliably connected to the concrete outer tank 1 through an anchoring connector composed of an anchoring stud 13, an anchoring nut 16, and an insulating plug 12. The thickness of the perlite concrete layer 2 is between 200 - 500 mm, and it has two main functions: First, the perlite concrete layer has a low thermal conductivity and can provide good adiabatic and insulation effects, forming an adiabatic barrier between the first embedded plate 10, the second embedded plate 15, the connecting rod 11, the reinforcing plate 14, and the concrete outer tank 1 to block the heat transfer through the first embedded plate 10 and the second embedded plate 15; Second, the perlite concrete layer has a high compressive strength, providing a foundation for the installation of the first embedded plate 10, the second embedded plate 15, and the reinforcing plate 14, and at the same time can withstand the stress generated by the shrinkage deformation of the inner tank, improving the overall strength of the corner connection structure. The high-strength polyurethane foam layer 3 is located between the perlite concrete layer 2 and the insulating blocks 4 and is connected to the perlite concrete layer 2 through an anchoring connector composed of an anchoring stud 13, an anchoring nut 16, and an insulating plug 12. Its thickness is between 200 - 400 mm, mainly playing the role of adiabatic and insulation, forming an adiabatic barrier around the connecting rod 11 to reduce heat leakage and unnecessary heat transfer. The bearing plate 5 is mainly located on the back of the corner plate 9 and the back of the corrugated plate 6, that is, the first part 51 is located on the back of the corrugated plate 6 and the second part 52 is located on the back of the corner plate 9. The thickness of the bearing plate 5 is between 10 - 50 mm, and its main function is to enhance the compressive strength of the polyurethane foam and provide support for the installation of the first embedded plate 10 and the second embedded plate 15.

[0090] The corner sealing structure in the present invention mainly consists of a corner plate 9, a corrugated plate 6, a corrugated head 7, and a first embedded plate 10 and a second embedded plate 15. Its main function is to form an overall seal at the corner connection, facilitating welding with the inner tank of the film tank to form the entire closed space. Among them, the corner plate 9 is L-shaped, with a thickness between 6 - 10 mm. It is the main load-bearing and sealing component of the corner connection structure. The edge is welded to the corrugated plate 6 and the corrugated head 7. The two right-angled sides of the L-shaped corner plate 9 are welded to the second embedded plate 15 through welding holes 8, thus forming a complete closed space.

[0091] The anchoring reinforcement in the present invention mainly refers to the first embedded plate 10, the second embedded plate 15, the connecting rod 11 and the reinforcing plate 14. The second embedded plate 15 is welded to the corner plate 9. The first embedded plate 10 is buried in the perlite concrete layer 2. The first embedded plate 10 and the second embedded plate 15 are connected by the connecting rod 11 to form an integral unit and are buried in the perlite concrete layer 2. The corner plate 9 is made of stainless steel, 9% nickel steel or steel plates of other materials; the diameter of the connecting rod 11 is 8 - 20 mm, and the length is between 600 - 1200 mm. It can be prefabricated according to the actual situation. The material is stainless steel or steel with equivalent strength, and the weldability with the first embedded plate 10 and the second embedded plate 15 needs to be ensured. Considering the characteristics of the perlite concrete layer 2 that it is compressive but not tensile, the reinforcing plate 14 is prefabricated inside it. The reinforcing plate 14 is provided with holes for the connecting rod 11 to pass through, and direct contact between the connecting rod 11 and the reinforcing plate 14 should be avoided to reduce heat transfer and loss. The material of the reinforcing plate 14 is ordinary carbon steel or 9% nickel steel, and the thickness is between 5 - 10 mm.

[0092] More specifically, as Figure 1 and Figure 2 shown, a corner connection structure of a large LNG thin-film tank designed by the present invention, each component is a concrete outer tank 1, a perlite concrete layer 2, a high-strength polyurethane foam layer 3, an insulating block 4, a bearing plate 5 (including a first part 51 and a second part 52), a corrugated plate 6, a corrugated head 7, a welding hole 8, a corner plate 9, a first embedded plate 10, a connecting piece 11, an insulating plug 12, an anchoring stud 13, a reinforcing plate 14, a second embedded plate 15 and an anchoring nut 16. The above-mentioned various components are connected reasonably to achieve the effects of heat insulation and pressure sealing, and finally serve as the direct components of the corner area of the thin-film tank.

[0093] In the above specific implementation, the perlite concrete layer 2 is reliably connected to the concrete outer tank 1 through an anchoring connection composed of an anchoring stud 13, an anchoring nut 16 and an insulating plug 12. The density of the perlite concrete layer 2 needs to be maintained at about 1000 kg / m 3 ³, the thermal conductivity is not higher than 0.22 W / (m·K), and the average compressive strength is not less than 6.0 MPa. The perlite concrete layer is generally prefabricated into blocks in advance, and the thickness is between 200 - 500 mm. When prefabricating, installation holes for the anchoring stud 13 need to be reserved. And in special cases, the first embedded plate 10, the connecting rod 11 and the reinforcing plate 14 should be prefabricated in the perlite concrete layer 2 at the same time, and the relative position accuracy should be ensured. During installation, the installation holes of the perlite concrete layer 2 are aligned with the anchoring studs 13 of the concrete outer tank 1, and the other end is fastened by the anchoring nut 16, and the insulating plug 12 is filled. The perlite concrete layer 2 only needs to be installed in the corner area, and the height at the tank wall and the length at the tank bottom both need to be maintained between 1000 - 1500 mm.

[0094] In the above specific implementation, the insulating plug 12 is mainly used to fill the prefabricated stud holes, playing a role in enhancing the heat insulation and heat preservation effect. Its material can be polyurethane foam, glass fiber, and other flexible and rigid insulating materials.

[0095] In the above specific implementation, the high-strength polyurethane foam layer 3 is connected to the perlite concrete layer 2 through an anchoring connector composed of an anchoring stud 13, an anchoring nut 16, and an insulating plug 12 to form a second heat insulation and heat preservation layer with a thickness between 200 - 400 mm. The polyurethane foam layer 3 can be constructed by two methods: prefabrication and on-site spraying. When prefabricating, the reserved installation holes for the anchoring studs should be considered. In the area near the connecting rod 11, on-site spraying can be used for construction to better fit with the connecting rod 11, reduce heat leakage and heat transfer, and enhance the heat insulation and heat preservation effect. The laying of the high-strength polyurethane foam layer 3 should avoid the gaps in the perlite concrete layer to achieve staggered joint laying.

[0096] In the above specific implementation, the insulating blocks 4 are mainly located under the corner plate 9 and under the corrugated plate 6, with a thickness between 50 - 200 mm, and are connected to the high-strength polyurethane foam layer 3 by means of glue bonding. The main function of the insulating blocks 4 is to form a buffer between the corrugated plate 6, the corner plate 9, and the high-strength polyurethane foam layer 3 to enhance the insulation effect. At the same time, installation gaps are reserved between the insulating blocks 4 to provide space for contraction and elongation due to cold deformation. The installation of the insulating blocks 4 should also avoid the installation gaps of the high-strength polyurethane foam layer 3 to achieve staggered joint installation. The material of the insulating blocks 4 is polyurethane foam or glass fiber.

[0097] In the above specific implementation, the first part 51 of the bearing plate 5 is located between the corrugated plate 6 and the insulating block 4, and the second part 52 is located under the corner plate 9. Its main function is to enhance the compressive strength and provide a bearing foundation for the installation of the second embedded plate 15. The thickness of the bearing plate 5 is 10 - 100 mm, and the main materials are plywood, polytetrafluoroethylene plate, etc. The bearing plate 5 is connected to the insulating block 4 by glue bonding, and installation gaps are reserved between the bearing plates 5 to be consistent with the insulating blocks 4. For the bearing plate 5 penetrated by the second embedded plate 15 and the connecting rod 11, a splicing method can be adopted, and it can be prefabricated in advance into corresponding sizes and shapes for convenient construction operation.

[0098] In the above specific implementation, the corrugated plate 6 is made of stainless steel plate or 9% nickel steel plate, with a thickness between 0.8 - 3 mm, having regular convex and flat areas, and can meet the deformation requirements caused by temperature changes. The size of a single corrugated plate 6 is between 500 - 1500 mm, and the corrugated plates 6 are connected by lap welding.

[0099] In the above specific implementation, the corrugated head 7 serves as the terminal seal of the corrugated plate, playing the role of sealed connection. Its material and thickness should be consistent with those of the corrugated plate 6. The corrugated head 7 is directly welded to the corner plate 9, and the welding hole 8 is covered below to ensure the tightness of the entire inner tank.

[0100] In the above specific implementation, the welding hole 8 is opened on the corner plate 9. Its main function is to weld the corner plate 9 to the second embedded plate 15, enhancing the overall strength of the corner connection structure and providing support for the corner plate 9 to bear radial and circumferential loads. The size of the welding hole 8 should be smaller than that of the corrugated head 7, and the opening position should facilitate welding operations. After welding, airtightness inspection should be carried out to ensure the welding quality.

[0101] In the above specific implementation, the corner plate 9 is one of the core components of the entire corner connection structure and is the main load-bearing and sealing component of the corner connection structure. It is generally L-shaped, with a thickness between 6 - 20 mm and a length between 1500 - 2000 mm. The corner plate 9 is fixedly connected to the second embedded plate 15 through the welding hole 8 and can bear radial and circumferential loads. In the corner area, the corner plate 9 forms a closed annular bearing platform in the corner area by welding, and the corrugated plate 6 is welded to the corner plate 9, thus forming a complete closed space for the inner tank.

[0102] In the above specific implementation, the embedded parts include the first embedded plate 10, the second embedded plate 15, and the connecting rod 11. Among them, the second embedded plate 15 is welded to the corner plate 9, the first embedded plate 10 is buried in the perlite concrete layer 2, and the first embedded plate 10 and the second embedded plate 15 are connected by the connecting rod 11 to form a whole and are buried in the perlite concrete layer 2. The materials of the first embedded plate 10 and the second embedded plate 15 are stainless steel, 9% nickel steel, or steel plates of other materials; the diameter of the connecting rod 11 is 8 - 20 mm, and the length is between 600 - 1200 mm. It can be prefabricated according to the actual situation, and the material is stainless steel or steel with the same strength, and the weldability with the first embedded plate 10 and the second embedded plate 15 needs to be ensured.

[0103] In the above specific implementation, to enhance the adiabatic and heat insulation effect and reduce heat leakage through the stud holes, the insulating plug 12 needs to be filled after the anchor nut 16 is installed. The material of the insulating plug 12 is polyurethane foam, flexible insulating material, etc.

[0104] In the above specific implementation, to enhance the connection strength between the perlite concrete layer 2 and the high-strength polyurethane foam layer 3, the anchor stud 13 needs to be embedded, which is convenient for positioning and installation. The material of the anchor stud 13 is ordinary carbon steel, 9% nickel steel, or steel with higher strength. The length of the anchor stud 13 is determined according to the on-site construction, generally 200 - 500 mm, and the diameter is 8 - 20 mm.

[0105] In the above specific implementation, considering the characteristics of the perlite concrete layer 2 that it is compressive but not tensile, a reinforcing plate 14 is prefabricated inside it. Holes are reserved on the reinforcing plate 14 for the connecting rod 11 to pass through. The diameter of the holes is twice or more than the diameter of the connecting rod 11, and direct contact between the connecting rod 11 and the reinforcing plate 14 should be avoided to reduce heat transfer and loss. The material of the reinforcing plate 14 is ordinary carbon steel or 9% nickel steel, and the thickness is between 5-10 mm. The number and laying position of the reinforcing plates 14 can be flexibly arranged to enhance the tensile strength of the perlite concrete layer 2. Similarly, a wire mesh can also be laid in layers during the prefabrication of the perlite concrete layer 2 to enhance the tensile strength of the perlite concrete layer.

[0106] It can be seen that the corner connection structure provided by the present invention has the advantages of simple configuration, convenient construction, easy guarantee of strength, good heat insulation and heat preservation effects, etc. It will effectively replace the original structure, greatly simplify the on-site construction process, improve the construction quality, and is of great significance for promoting the localization process of LNG membrane tanks.

[0107] The above are only the preferred embodiments of the present invention and are not used to limit the scope of implementation of the present invention; if the present invention is modified or equivalently replaced without departing from the spirit and scope of the present invention, it shall be covered by the protection scope of the claims of the present invention.

Claims

1. A corner connection structure for an LNG membrane tank, characterized in that, Comprising: A concrete outer tank, with a perlite concrete layer, a polyurethane foam layer, and an insulating block connected in sequence on the inner side of the concrete outer tank; Load-bearing plates respectively located on the vertical side and the horizontal side of the corner area, each load-bearing plate is connected to the insulating block, each load-bearing plate has a first part and a second part connected to the end of the first part, and a corrugated plate is carried on each load-bearing plate; A corner plate, the corner plate is in an arc-shaped L shape, the corner plate is positioned between the load-bearing plate on the vertical side and the load-bearing plate on the horizontal side, the vertical part of the corner plate is connected above the second part of the load-bearing plate on the vertical side and connected to the first part, the horizontal part of the corner plate is connected above the second part of the load-bearing plate on the horizontal side and connected to the first part, and the arc part of the corner plate is connected to the insulating block; A corrugated head, the corrugated head connects the end of the corrugated plate adjacent to the corner plate and is welded to the corner plate.

2. The corner connection structure for an LNG membrane tank according to claim 1, characterized in that, It further comprises: Anchoring reinforcement members respectively located on the vertical side and the horizontal side of the corner area, each anchoring reinforcement member includes a reinforcement plate, a first embedded plate, a connecting member, and a second embedded plate, the reinforcement plate is fixed in the perlite concrete layer, the first embedded plate is positioned in the perlite concrete layer and under the reinforcement plate, the second embedded plate is positioned in the second part of the bearing plate and is welded and fixed to the corner plate through the welding holes on the corner plate, and the connecting member connects the first embedded plate and passes through the reinforcement plate to connect to the second embedded plate.

3. The corner connection structure for an LNG membrane tank according to claim 2, characterized in that, It further comprises: An anchoring connecting member, the anchoring connecting member includes an anchoring stud, an anchoring nut, and an insulating plug, the anchoring stud is inserted into the hole and tightened by the anchoring nut and the insulating plug is filled in the hole.

4. The corner connection structure for an LNG membrane tank according to claim 3, characterized in that, The perlite concrete layer is fixedly connected to the concrete outer tank through the anchoring connecting member; the polyurethane foam layer is fixedly connected to the perlite concrete layer through the anchoring connecting member.

5. The corner connection structure for an LNG membrane tank according to claim 4, characterized in that, The density of the perlite concrete layer is 1000 kg / m 3 , the thermal conductivity is not higher than 0.22 W / (m·K), and the average compressive strength is not less than 6.0 MPa.

6. The corner connection structure for an LNG membrane tank according to claim 5, characterized in that, The perlite concrete layer is prefabricated into blocks in advance, with a thickness of 200 - 500 mm, and holes for installing the anchoring studs are reserved during prefabrication.

7. The corner connection structure for an LNG membrane tank according to claim 3, characterized in that, The thickness of the polyurethane foam layer is 200 - 400 mm.

8. The corner connection structure for an LNG membrane tank according to claim 7, characterized in that, The polyurethane foam layer is obtained by prefabrication and on-site spraying, and holes for installing the anchoring studs are reserved during prefabrication.

9. The corner connection structure for an LNG membrane tank according to claim 1, characterized in that, The polyurethane foam layer and the perlite concrete layer are laid with staggered joints.

10. The corner connection structure for an LNG membrane tank according to claim 1, characterized in that, The thickness of the insulating block is 50 - 200 mm.

11. The corner connection structure for an LNG membrane tank according to claim 1, characterized in that, The insulating block is connected to the polyurethane foam layer by means of glue bonding.

12. The corner connection structure for an LNG membrane tank according to claim 1, characterized in that, The insulating block and the polyurethane foam layer are installed with staggered joints.

13. The corner connection structure for an LNG membrane tank according to claim 1, characterized in that, The material of the insulating block is polyurethane foam or glass fiber.

14. The corner connection structure for an LNG membrane tank according to claim 1, characterized in that, The thickness of the load-bearing plate is 10 - 100 mm, and the material of the load-bearing plate is plywood or polytetrafluoroethylene plate.

15. The corner connection structure for an LNG membrane tank according to claim 1, characterized in that, The load-bearing plate is connected to the insulating block by means of glue bonding, and an installation gap is reserved between the load-bearing plates and the gap is consistent with the gap on the insulating block.

16. The corner connection structure of the LNG thin-film tank according to claim 1, wherein The corrugated plate is made of stainless steel plate or 9% nickel steel plate, and the thickness of the corrugated plate is 0.8 - 3 mm.

17. The corner connection structure of the LNG thin-film tank according to claim 16, wherein The number of the corrugated plates is multiple, and the corrugated plates are connected in a form of lap welding.

18. The corner connection structure of the LNG thin-film tank according to claim 1, wherein The thickness of the corner plate is 6 - 20 mm, and the length is 1500 - 2000 mm.

19. The corner connection structure of the LNG thin-film tank according to claim 2, wherein Both the first embedded plate and the second embedded plate are made of stainless steel plate or 9% nickel steel plate, and the diameter of the connecting rod is 8 - 20 mm, and the length is 600 - 1200 mm.

20. The corner connection structure of the LNG thin-film tank according to claim 3, wherein The material of the anchor stud is carbon steel or 9% nickel steel, and the length of the anchor stud is 200 - 500 mm, and the diameter is 8 - 20 mm.

21. The corner connection structure of the LNG thin-film tank according to claim 2, wherein The material of the reinforcing plate is carbon steel or 9% nickel steel, and the thickness is 5 - 10 mm.

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