Large LNG storage tank dome structure

Abstract

The utility model discloses a large -scale LNG storage tank dome structure, including outer tank wall, outer vault, inner tank wall and inner vault, and outer vault and inner vault are all the spherical shape of the convex upwards, and the lower extreme of outer vault is connected with the upper extreme of outer tank wall, and inner tank wall is located the inner side of outer tank wall, and the lower extreme of inner vault is connected with the upper extreme of inner tank wall, and outer vault, outer tank wall, inner vault and inner tank wall enclose the filling space, and the filling space is equipped with cold insulation material. The application reduces the height and gravity center of storage tank under the condition of same effective tank capacity, improves the operation and use condition of storage tank, makes storage tank more safe. Can improve LNG liquid level in operation, can reduce the storage tank shock isolation measure in construction. Realize the self -flow of perlite powder filling, self -compensation, guarantee the cold insulation quality of tank wall. Realize the good operation condition of cold insulation construction, cancel the construction of glass wool. Reduce the height of outer tank, reduce the construction material of outer tank.

Description

Technical Field

[0001] This utility model relates to the field of LNG storage tank technology, and in particular to a dome structure for a large LNG storage tank. Background Technology

[0002] With the development of my country's LNG industry, the number of LNG storage tanks is increasing, and their capacity is also gradually expanding. Common large LNG storage tanks range in capacity from 100,000 cubic meters to 270,000 cubic meters. The top of a large LNG storage tank is typically an arched spherical structure called a dome. The dome is an important component of the LNG storage tank, used to support the top equipment and connect the surrounding annular tank walls to form the working tank volume. The dome of a large LNG storage tank usually has a span exceeding 150 meters, a base elevation exceeding 40 meters, and a weight of approximately 1,000 tons. Due to its large span, high position, and heavy weight, the dome of a large LNG storage tank is the most difficult and technologically complex part to construct.

[0003] Traditional large LNG storage tanks have a dome structure consisting of a combination of a dome and an aluminum suspended ceiling, such as... Figure 1 As shown. The outermost and uppermost layer of the dome is a reinforced concrete second arch 1, the middle layer is a spherical carbon steel first arch 2, and the lower layer is a suspended horizontal aluminum ceiling 3. The aluminum ceiling 3 is suspended below the first arch. The weight of the first arch 2 and the second arch 1 rests on the concrete outer tank wall 4. The aluminum ceiling 3 and the nickel steel inner tank wall 5 enclose the LNG storage working space.

[0004] Currently, the domes of existing large LNG storage tanks are typically constructed using a combination of reinforced concrete, an inner carbon steel arch, and an aluminum ceiling. Because the lower aluminum ceiling is horizontal and requires glass wool insulation, it occupies considerable height, reducing the tank space and the effective height of the LNG inside. During operation, the LNG level must be strictly controlled to prevent tumbling or excessively high levels during filling, which could cause LNG to contact the aluminum ceiling, overflow, or even enter the space above the aluminum ceiling, damaging the carbon steel arch in the middle layer of the dome. This necessitates a taller dome, outer tank, and inner tank for the same effective tank capacity, resulting in a higher center of gravity and requiring vibration damping and isolation measures. Furthermore, the aluminum ceiling structure requires regular inspection of the expanded perlite insulation in the annular space between the inner and outer tanks; any local collapses or deficiencies necessitate replenishment. Utility Model Content

[0005] The purpose of this application is to provide a large LNG storage tank dome structure to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, this application provides the following technical solution:

[0007] A large LNG storage tank dome structure includes an outer tank wall, an outer dome, an inner tank wall, and an inner dome. Both the outer and inner domes are upwardly convex spherical shapes. The lower end of the outer dome is connected to the upper end of the outer tank wall. The inner tank wall is located inside the outer tank wall. The lower end of the inner dome is connected to the upper end of the inner tank wall. The outer dome, outer tank wall, inner dome, and inner tank wall enclose a filling space, and the filling space is filled with cold insulation material.

[0008] Optionally, the outer dome includes a first dome and a second dome, the inner surface of the second dome is in contact with the outer surface of the first dome, and a filling opening is provided at the center of the first dome and the second dome, the filling opening being in communication with the filling space.

[0009] Optionally, the distance between the first arch and the inner arch is 400mm-600mm.

[0010] Optionally, the distance between the first arch and the inner arch is 500 mm.

[0011] Optionally, the inner dome is made of aluminum.

[0012] Optionally, the insulation material is expanded perlite.

[0013] Optionally, the outer tank wall is made of concrete; and / or, the inner tank wall is made of nickel steel.

[0014] Optionally, the first arch is made of carbon steel, and / or the second arch is a reinforced concrete arch.

[0015] In summary, the technical effects and advantages of this utility model are as follows: Under the same effective tank capacity, it reduces the height and center of gravity of the storage tank, improves the operating conditions, and makes the tank safer. During operation, it can increase the LNG level, and during construction, it can reduce the need for vibration damping and isolation measures. It achieves self-flowing and self-compensating perlite powder filling, ensuring the insulation quality of the tank wall. It achieves single, concentrated filling of perlite powder, improving the convenience and continuity of construction. It provides excellent working conditions for insulation construction, eliminating the need for glass wool. It reduces the height of the outer tank and the amount of construction materials required for the outer tank. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1A schematic diagram of the dome structure of a large LNG storage tank in the prior art;

[0018] Figure 2 This is a schematic diagram of the structure of a large LNG storage tank dome in one embodiment of the present invention;

[0019] Figure 3 This is a top view of the dome structure of a large LNG storage tank in one embodiment of the present invention.

[0020] Among them: 1. Second arch; 2. First arch; 3. Aluminum ceiling; 4. Outer tank wall; 5. Inner tank wall; 6. Inner arch; 7. Filling port. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0022] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0023] To increase the effective capacity of large LNG storage tanks, reduce the height occupied by horizontal aluminum ceilings and insulation, and improve the insulation working environment and insulation quality, this embodiment proposes a dome structure for large LNG storage tanks, eliminating the need for horizontal ceiling structures, such as... Figure 2 and Figure 3 As shown, the tank includes an outer tank wall 4, an outer dome, an inner tank wall 5, and an inner dome 6. Both the outer dome and the inner dome 6 are spherical shapes that bulge upwards. The lower end of the outer dome is connected to the upper end of the outer tank wall 4. The inner tank wall 5 is located inside the outer tank wall 4. The lower end of the inner dome 6 is connected to the upper end of the inner tank wall 5. The outer dome, outer tank wall 4, inner dome 6, and inner tank wall 5 form a filling space, and the filling space is filled with cold insulation material.

[0024] This embodiment improves the traditional horizontal ceiling structure into an upward-protruding spherical inner arch structure, which can increase the effective capacity of the LNG storage tank, reduce the height of the tank, lower the center of gravity of the LNG storage tank during operation, and improve the seismic performance of the tank.

[0025] Optionally, the outer dome includes a first dome 2 and a second dome 1, with the inner surface of the second dome 1 fitting against the outer surface of the first dome 2. A filling opening 7 is provided at the center of the first dome 2 and the second dome 1, and the filling opening 7 communicates with the filling space. Insulating material is filled into the filling space through the filling opening 7; during construction, the sheet-like components of the inner dome 6 can also be hoisted through this filling opening 7. Optionally, the insulating material is expanded perlite.

[0026] This embodiment uses a single, centralized filling port 7 instead of multiple circumferentially distributed filling ports 7. This transforms the dispersed, multi-point filling into a centralized, fixed-point filling. The centralized, unique filling port 7 at the top center of the tank facilitates construction. After pre-cooling and commissioning of the tank, if the expanded perlite in a certain area of ​​the tank wall settles after a period of operation, the top expanded perlite can automatically flow down to replenish it. The height of the top expanded perlite is easily checked, measured, and replenished, achieving self-compensating filling of the expanded perlite in the tank wall and ensuring the insulation quality of the tank wall. It also reduces the need for filling multiple ports 7 one by one, avoiding leakage of expanded perlite during movement; and eliminates the need for glass wool construction, greatly improving the construction conditions for insulation.

[0027] Optionally, the distance between the first dome 2 and the inner dome 6 is 400mm-600mm. Preferably, the distance between the first dome 2 and the inner dome 6 is 500mm; this is used for filling and flowing expanded perlite. The gap between the first dome 2 and the inner dome 6 is completely connected to the annular space between the lower inner tank wall 5 and the outer tank wall 4, allowing the expanded perlite above to flow freely down and fill the annular space between the inner tank wall 5 and the outer tank wall 4.

[0028] In this embodiment, the weight of the first dome 2 and the second dome 1 still rests on the outer tank wall 4, as in the conventional method. However, in this embodiment, the weight of the inner dome 6 rests on the inner tank wall 5, and the inner dome 6 and the inner tank wall 5 form a larger working space for LNG storage than in the conventional structure. Because the inner dome 6 is higher than the overall height of the horizontal ceiling, cryogenic LNG is less likely to come into contact with and overflow from the inner dome 6, greatly improving the LNG level operating conditions of the storage tank.

[0029] Optionally, the inner dome 6 is made of aluminum; and / or, the inner tank wall 5 is made of nickel steel. The bottom of the inner dome 6 is welded to the nickel steel inner tank wall 5 (with a stainless steel transition weld in the middle), and the weight of the inner dome 6 rests on the nickel steel inner tank wall 5. By using the inner dome 6 and lowering the center of gravity of the storage tank, vibration damping and isolation measures and the height of the outer tank can be reduced according to the storage tank capacity, center of gravity height, and local geological conditions. Specifically, the inner dome 6 can be made of A7075-T652 ultra-hard aluminum material, suitable for low-temperature environments down to -170 degrees Celsius, meeting the operating requirements of the storage tank, with a small coefficient of expansion and high stability; tensile strength up to 400MPa, density 2.8kg / cm3, which can realize the large span of the inner dome 6 and the load-bearing capacity of expanded perlite, meeting construction requirements.

[0030] Optionally, the outer tank wall 4 is made of concrete. Optionally, the first arch 2 is made of carbon steel, and / or the second arch 1 is a reinforced concrete arch.

[0031] Implementation method:

[0032] During construction, after the first carbon steel arch is completed, the watermelon rind-shaped components of the inner arch (referred to as "watermelon rinds" in the construction process) are welded and fabricated on the original carbon steel first arch construction jig. The inner arch can be symmetrically divided into 18, 24, or 32 "watermelon rinds", each weighing approximately 10 tons.

[0033] When the inner tank construction is basically completed, the inner dome "pieces" are transported into the tank through the temporary large opening for tank construction. One end of each "piece" is hoisted through a pressure ring (similar to the hoisting of the nickel steel inner tank wall panels), and the other end is hoisted through the central filling opening at the top of the dome. After each "piece" is in place, one end rests on the inner tank wall and is fixed by the pressure ring, while the other end is fixed to the carbon steel first dome through the filling opening at the top of the dome. After the inner dome "pieces" are symmetrically hoisted and all are in place, their bottoms are welded and connected to the nickel steel inner tank wall panels (with an intermediate weld of SS304 stainless steel). The longitudinal seams between the "pieces" are welded using a welding robot, moving from top to bottom along the surface of the inner dome from the filling opening position. During welding, the welding robot is guided by the skeleton beam of the carbon steel outer dome above. After the longitudinal seams are welded, the central circle at the top of the inner dome is welded in place.

[0034] In summary, this embodiment reduces the height and center of gravity of the storage tank while maintaining the same effective tank capacity, improving operating conditions and enhancing safety. It allows for higher LNG levels during operation and reduces the need for vibration damping and isolation measures during construction. The self-flowing and self-compensating perlite powder filling ensures excellent insulation quality of the tank walls. The single, concentrated filling of perlite powder facilitates convenient and continuous construction. It provides favorable working conditions for insulation construction, eliminating the need for glass wool. It also reduces the height of the outer tank and the amount of construction materials required.

[0035] For ease of explanation, spatial relative terms such as "upper," "lower," "outer," and "inner" are used in the embodiments to describe the relationship of one element or feature relative to another element or feature shown in the figures. It should be understood that, in addition to the orientations shown in the figures, spatial terms are intended to include different orientations of the device during use or operation. Therefore, the exemplary term "lower" can encompass both upper and lower orientations.

[0036] Moreover, relational terms such as “3” and “4” are merely used to distinguish one component from another that has the same name, without necessarily requiring or implying any such actual relationship or order between the components.

[0037] Although the preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not limiting. Those skilled in the art can make many specific modifications under the guidance of the present invention without departing from the spirit and scope of the claims, and these modifications all fall within the scope of protection of the present invention.

Claims

1. A dome structure for a large LNG storage tank, characterized in that, The tank includes an outer tank wall, an outer dome, an inner tank wall, and an inner dome. Both the outer and inner domes are spherical shapes that bulge upwards. The lower end of the outer dome is connected to the upper end of the outer tank wall. The inner tank wall is located inside the outer tank wall. The lower end of the inner dome is connected to the upper end of the inner tank wall. The outer dome, outer tank wall, inner dome, and inner tank wall enclose a filling space, and the filling space is filled with cold insulation material. The outer dome includes a first dome and a second dome. The inner surface of the second dome is attached to the outer surface of the first dome. A filling port is provided at the center of the first dome and the second dome, and the filling port is connected to the filling space. Cold insulation material is filled into the filling space through the filling port. During the construction period, the "melon slice" components of the inner dome are hoisted through the filling port. The inner dome is made of aluminum; the inner tank wall is made of nickel steel; the inner dome is symmetrically divided into 18, 24 or 32 "melon slices", the bottom of the "melon slices" is welded to the inner tank wall, the longitudinal seam between the "melon slices" is welded by a welding robot moving from top to bottom along the surface of the inner dome from the filling port position, and the center circle of the top of the inner dome is welded to the melon slices.

2. The large LNG storage tank dome structure according to claim 1, characterized in that, The distance between the first arch and the inner arch is 400mm-600mm.

3. The large LNG storage tank dome structure according to claim 1, characterized in that, The distance between the first arch and the inner arch is 500mm.

4. The large LNG storage tank dome structure according to claim 1, characterized in that, The insulation material is expanded perlite.

5. The large LNG storage tank dome structure according to claim 1, characterized in that, The outer tank wall is made of concrete.

6. The large LNG storage tank dome structure according to claim 1, characterized in that, The first arch is made of carbon steel, and / or the second arch is a reinforced concrete arch.

Images