KR20110051407A - Independence type liquified gas tank having double insulation layer - Google Patents

Abstract

PURPOSE: A stand-alone type liquefied gas tank is provided to reduce the time and effort for installation of insulation panels by employing a double insulation panel structure in which an insulation material is injection-molded between insulation panels. CONSTITUTION: A stand-alone type liquefied gas tank comprises a tank body(1) accommodating liquefied gas and an insulation layer which is installed on the exterior of the tank body by doubly laminating a plurality of insulation panels(10) and foaming an insulation material between the insulation panels to connect the insulation panels.

Description

Independent liquefied gas tank with double insulation layer {INDEPENDENCE TYPE LIQUIFIED GAS TANK HAVING DOUBLE INSULATION LAYER}

The present invention relates to a stand-alone liquefied gas tank that is installed to store liquefied gas, such as LNG or LPG, and more particularly, to a stand-alone liquefied gas tank in which a heat insulating layer for heat insulation is stacked in a double.

Natural gas is transported in a gaseous state through onshore or offshore gas piping, or transported to a distant consumer while being stored in an LNG carrier in the form of liquefied liquefied natural gas (LNG) or liquefied petroleum gas (LPG). Liquefied natural gas is obtained by cooling natural gas to cryogenic temperature (approximately -163 ℃), and its volume is reduced to about 1/600 than natural gas in gas state, so it is very suitable for long distance transportation through sea.

LNG transporter for loading and unloading LNG to land requirements by operating the sea with LNG The vessel includes a storage tank (commonly referred to as a "cargo hold") capable of withstanding cryogenic temperatures of liquefied natural gas.

These storage tanks can be classified into independent type and membrane type depending on whether the load directly affects the insulation material.Membrane type storage tanks are usually GT NO 96 type and TGZ Mark III type. Independent storage tanks are divided into MOSS type and SPB type. The structure of the MOSS type independent storage tank is described in Korean Patent No. 10-15063 and the like, and the structure of the SPB type independent storage tank is described in Korean Patent No. 10-305513 and the like.

In general, stand-alone storage tanks are made by attaching a relatively rigid insulation panel such as polyurethane to a tank body made of aluminum alloy, SUS, and 9% nickel, such as low temperature resistant alloy, and arranged on the inner bottom of the hull. Is placed on the support.

The insulation structure of a liquefied gas storage tank for installing a plurality of insulation panels made of polyurethane foam on the outside of the tank body is described in Korean Patent No. 10-166608.

According to the heat insulation structure of the independent liquefied gas tank according to the prior art, a heat insulating panel having a substantially hexahedron shape is successively attached to the outside of the tank body to prevent heat from being transferred to the liquefied gas contained in the tank. Insulating panels are manufactured to have a predetermined calculated thickness to block heat transfer.

In addition, a heat insulating material having elasticity even at low temperatures between the heat insulating panels arranged on the outside of the tank body so as to properly act according to the shrinkage of the tank body due to receiving the cryogenic liquefied gas to prevent the occurrence of stress in the heat insulating panel. Is installed.

According to the prior art, in order to attach one insulation panel to the outside of the tank body, first attaching a mounting member such as a stud to the outside of the tank body by welding, and then joining the cylindrical member and the supporting member to the mounting member, Subsequently, the insulation panel was fitted to the support member to perform the work of fastening with the washer and the nut. Here, the support member is a rod-shaped rod with threads formed at both ends, and the cylindrical member is a part interposed between the mounting member and the heat insulation panel to protect the heat insulation panel.

In general, when arranging a large thermal insulation panel in the tank body than the case of arranging a small thermal insulation panel in the tank body, less mounting members such as studs can be installed, so from the outside to the tank body through the mounting member It is easy to block the heat transferred. Furthermore, it is preferable to reduce the number of parts for attaching the insulation panel and to shorten the working time.

However, in the heat insulation structure of the liquefied gas storage tank according to the prior art, since the heat insulation panel must have a predetermined thickness as described above, the size of one heat insulation panel in consideration of the workability when installing the heat insulation panel and the like. There is a limit that cannot be increased more than.

Therefore, it is possible to attach a larger insulation panel to the tank body, at the same time can further reduce the time and effort required for the attachment work, and to reduce the heat transfer from the outside of the storage tank as much as possible, the liquefied gas storage tank There is a continuing need for research on the thermal insulation of ethanol.

In addition, according to the prior art, the insulation panel and the other insulation panel is arranged to be spaced apart at regular intervals. A step is formed at the edge of the heat insulation panel, and a room temperature side gap farther from the tank body is formed wider than the low temperature side gap close to the tank body.

The low temperature side gap is filled with an insulating material such as glass wool having elasticity at low temperature, and the high temperature side gap is filled with an insulating material such as polyethylene foam having higher elasticity than the insulating panel at a temperature close to room temperature. It is. Insulating tape is attached to block the interface between the low temperature side gap and the normal temperature side gap.

According to the insulation panel connection structure of the prior art configured as described above, when liquefied gas leaks from the tank body, the liquefied gas leaked by the insulation tape can be prevented from falling through the insulation panel to the bottom of the hull. In addition, heat transfer to the outside may be excluded by the insulating materials filled in the low temperature side gap and the room temperature side gap.

However, even if repeated heat deformation caused by loading or unloading liquefied gas inside the storage tank is applied, the heat insulation from the outside is reliably blocked due to its high insulation performance and high elasticity so that the connection structure between the insulation panels is not damaged. There is a continuing need for research on the connection structure of insulating panels.

In addition, research on securing the ventilation space between the tank body and the insulation panel, securing the support structure of the stable insulation panel, securing the airtightness to prevent liquefied gas leakage through the gap between the adjacent insulation panels also need to be made continuously.

In addition, it is possible to attach larger insulation panels to the tank body, while further reducing the time and effort required for attaching and connecting the insulation panels, and reducing heat transfer from the outside of the storage tank as much as possible. There is a continuing need for research on the thermal insulation of liquefied gas storage tanks.

The present invention for solving the above problems, by forming a thermal insulation panel in a double structure, by connecting the insulation panels by injection molding the insulation material in the gap between the insulation panels, one insulation panel attached to the outside of the tank body It is to provide a stand-alone liquefied gas tank that can reduce the parts required for installation by reducing the size of the installation, the time and effort required for installation work, and to reduce the heat transfer from the outside of the storage tank as much as possible.

According to the present invention for achieving the above object, an independent liquefied gas tank for storing the liquefied gas, the tank body for receiving the liquefied gas; A heat insulation layer installed outside the tank body; It includes, and the heat insulation layer is provided by a standalone liquefied gas tank, characterized in that formed by stacking a plurality of heat insulation panels double.

It is preferable that the plurality of heat insulation panels are connected to each other by foam molding a heat insulation material between the heat insulation panel and the heat insulation panel.

The heat insulation layer includes a plurality of primary insulation panels stacked on the tank body, and a plurality of secondary insulation panels stacked on each of the primary insulation panels, and the secondary insulation panels include the primary insulation It is desirable to be smaller than the panel.

The plurality of primary insulation panels are arranged to be in close contact with each other, an elastic member having a filling space therein is disposed between the plurality of secondary insulation panels, the filling space is preferably filled with a heat insulating material.

A stud bolt is installed outside the tank body, and the independent insulation gas tank is installed on the outside of the tank body through a fixing member coupled to the primary insulation panel and the secondary insulation panel. .

The fixing member may include a fastening portion screwed to the stud bolt, an extension portion extending from the fastening portion, and coupled to the secondary heat insulating panel, and in a radial direction to fix the primary heat insulating panel. It is preferable to include the flange part which protrudes and is caught by the step part formed in the said primary heat insulation panel.

In order to connect the primary insulation panels to each other, a connection member is attached on the adjacent primary insulation panels along a boundary of the plurality of primary insulation panels, so that the connection member can remain attached during thermal deformation. It is preferable that a folded part is formed.

According to the present invention as described above, an independent liquefied gas tank having a double structure of a heat insulation panel attached to the outside of the tank body can be provided.

Accordingly, according to the present invention, by increasing the size of one insulation panel attached to the outside of the tank body, it is possible to reduce the components required for installation and to reduce the time and effort required for the installation work, from the outside of the storage tank It is possible to reduce heat transfer as much as possible.

In addition, according to the present invention, when attaching the insulation panel to the tank body, it is easy to be carried out for the connection between the insulation panel and another insulation panel, it is possible to provide a connection structure excellent in the elasticity and insulation effect during thermal deformation. have.

Hereinafter, a standalone liquefied gas tank according to a preferred embodiment of the present invention will be described in detail with reference to the drawings.

1 is a partial cross-sectional view of the thermal insulation structure of a standalone liquefied gas tank according to a preferred embodiment of the present invention. Figure 2 is a cross-sectional view showing the disassembled parts to explain the thermal insulation panel coupling structure of the independent liquefied gas tank according to the present invention, Figure 3 is a thermal insulation panel coupling according to the present invention coupled to the outside of the tank body A cross section of the structure is shown. And Figure 4 is a cross-sectional view showing the disassembled parts to explain the insulation panel connection structure of the independent liquefied gas tank according to the present invention, Figure 5 is a thermal insulation panel according to the present invention coupled to the outside of the tank body A cross-sectional view of the connection structure is shown.

As shown in FIG. 1, the independent liquefied gas tank is formed by attaching a relatively hard heat insulating panel 10 such as polyurethane foam to the outside of the tank body 1 to form a heat insulating layer. That is, the heat insulation panel 10 may have a substantially hexahedral shape, and the heat insulation layer is formed by successively installing the plurality of heat insulation panels 10 on the tank body 1 of the storage tank.

The tank body 1 and the heat insulation panel 10 are not completely contacted with each other and spaced apart from each other so that a gap is formed by a pad. The gap between the tank body 1 and the thermal insulation panel 10 can be utilized as a ventilation space and can also be used as a passage of the leaking liquid when a leak occurs due to damage of the tank body 1.

As shown in Figures 1 to 3, according to the insulating panel coupling structure of the independent liquefied gas tank according to a preferred embodiment of the present invention, the stud bolt (3) is provided on the outer surface of the tank body (1) at regular intervals Is installed. The stud bolt 3 can be fixedly mounted on the outside of the tank body 1 by welding.

A pad (not shown) having a plate shape of a constant thickness may be arranged in close contact with the stud bolt 3 around the stud bolt 3. The pad is installed around the stud bolts 3 so that the size of the gap between the tank body 1 and the insulation panel 10 can be kept constant. The male thread is formed at the end of the stud bolt 3.

The primary heat insulation panel 11 is fitted to the stud bolt 3. To this end, a substantially circular first hole 12 may be formed in the primary insulation panel 11. A stepped portion 12a is formed on the inner circumferential surface of the first hole 12, and the inner diameter of the first hole 12 is far from the inner diameter of the side closer to the tank body 1 with respect to the stepped portion 12a. It is formed smaller than the inner diameter of. When the small diameter part is called the small diameter part 12b and the large diameter part is called the large diameter part 12c, it is preferable that the diameter of the small diameter part 12b has a dimension larger than the outer diameter of the stud bolt 3, It is more preferable to have the same dimension as the outer diameter of the fixing member 5 mentioned later.

The primary insulation panel 11 is preferably made of a material having excellent heat insulation performance while having a certain strength, such as polyurethane foam or reinforced polyurethane foam. The primary heat insulation panel 11 may include a first protective layer 13 laminated and attached to one side of a heat insulating material such as the polyurethane foam described above. The first protective layer 13 may be made of a low temperature steel material such as aluminum, an aluminum alloy, or SUS.

In order to couple the primary insulation panel 11 to the stud bolt 3, the fixing member 5 is fastened to the stud bolt 3. The fastening member 5a is screwed to the stud bolt 3 with the outer diameter of the same dimension as the inner diameter of the small diameter part 12b of the primary heat insulation panel 11, as mentioned above. And an extension part 5b extending from the fastening part 5a for joining the secondary insulation panel 15 as described later, and radially between the fastening part 5a and the extension part 5b. And a protruding flange portion 5c.

The plurality of primary insulation panels 11 may be fixed to the surface of the storage tank by the fixing member 5 to have a complete sealing structure.

The fastening portion 5a has a female thread that can be fastened to the male thread of the stud bolt.

The extension part 5b is attached to the stud bolt 3 with the fixing member 5 via the primary heat insulation panel 11 for attaching the primary heat insulation panel 11 to the outside of the tank body 1. When fastened, the ends of the extension portion 5b are formed to have a length that can protrude from the primary heat insulation panel 11.

The flange part 5c contacts the step part 12a formed in the 1st hole 12 of the primary heat insulation panel 11, and hold | maintains the primary heat insulation panel 11 fixedly.

Outside the extension part 5b, a first filling member 7 made of a heat insulating material such as EPS, for example, can be inserted to fill the empty space between the fixing member 5 and the large diameter part 12c. When the first filling member 7 is fitted to the extension portion 5b, it is preferable that the first filling member 7 may have a horizontal plane with the surface of the primary insulation panel 11 or have a size that protrudes finely.

As shown in the figure, the secondary insulation panel 15 is laminated on the upper surface of the primary insulation panel 11. The secondary insulation panel 15 has a substantially hexahedral shape but preferably has a smaller horizontal and vertical dimension than the primary insulation panel 11 in plan view.

The secondary insulation panel 15 may be fixed to the primary insulation panel 11 by being fitted into and coupled to the extension part 5b of the fixing member 5 described above. To this end, the secondary insulation panel 15 may have a substantially circular second hole 16 formed therein. A joining plate 18 is provided in the second hole 16 at the lower portion of the second hole 16, that is, at one side surface (lower surface in the drawing) of the secondary heat insulating panel 15. It may be formed integrally with). The coupling plate 18 is formed with a through hole 18a through which the extension 5b can pass.

The secondary insulation panel 15 can be fixed to one side of the primary insulation panel 11 by screwing the coupling plate 18 to the end of the extension portion 5b by the washer 8 and the nut 9. Can be.

After the fixing of the secondary insulation panel 15 by the washer 8 and the nut 9 is completed, the second filling member 19 can be fitted in the second hole 16. When the second filling member 19 is fitted into the second hole 16, the second filling member 19 may form a horizontal plane with the surface of the secondary insulation panel 11 or have a size that protrudes finely.

On the other hand, according to the present invention, although not shown in the figure, the shape of the second hole 16 has a stepped portion as in the above-described first hole, and the secondary insulation panel 15 is formed by using the stepped portion instead of the coupling plate. You may deform so that it may be fixed to the vehicle heat insulation panel 11 fixedly.

Like the primary insulation panel 11, the secondary insulation panel 15 is preferably made of a material having excellent heat insulation performance while having a certain strength such as polyurethane foam or reinforced polyurethane foam. The secondary heat insulating panel 15 may include a second protective layer 17 laminated and attached to one side of the heat insulating material such as the polyurethane foam described above. The second protective layer 17 may be made of a low temperature steel material such as aluminum, an aluminum alloy, or SUS.

As described above, according to the present invention, there is provided an independent liquefied gas tank in which a heat insulation panel attached to the outside of the tank body is formed in a double structure of a primary heat insulation panel and a secondary heat insulation panel.

Accordingly, according to the present invention, since a single insulation panel attached to the outside of the tank body can be divided into a primary and a secondary insulation panel, respectively, it is possible to work even if the size of the insulation panel is increased, the insulation panel is increased As a result, it is possible to reduce the parts required for installation, to reduce the time and effort required for installation work, and to reduce heat transfer from the outside of the storage tank as much as possible.

In addition, by forming the first and second protective layers in the primary and secondary insulating panels and connecting each of the first protective layer and the respective second protective layer to each other, the connected first and second protective layers are formed of the liquefied gas. It can be configured to serve as a sealing wall that can prevent the leaked liquefied gas from coming into direct contact with the hull upon leakage.

1, 4 and 5, according to the insulation panel connection structure of the standalone liquefied gas tank according to a preferred embodiment of the present invention, the primary insulation panel 11 on the outer surface of the tank body (1) ) And the secondary insulation panel 15 may be laminated while forming a double structure.

The primary heat insulation panel 11 stacked close to the tank body 1 is positioned to be in close contact with another adjacent primary heat insulation panel 11. The primary insulation panel 11 is preferably made of a material having excellent heat insulation performance while having a certain strength, such as polyurethane foam or reinforced polyurethane foam. Each primary heat insulating panel 11 may include a first protective layer 13 laminated and attached to one side of the heat insulating material such as the polyurethane foam described above. The first protective layer 13 may be made of a low temperature steel material such as aluminum, an aluminum alloy, or SUS.

The connection member 21 is attached on the first protective layer 13 to connect the primary insulation panels 11 to each other. The connecting member 21 may be made of an Al material having a glass cloth, and may have a substantially tape or strip shape. This connecting member 21 is attached on the adjacent primary insulation panel 11, ie, the first protective layer 13, by an cryogenic sealant. Thus, a gap that may exist between the primary insulation panels 11 can be sealed by the connecting member 21.

Although only a cross section is shown in FIGS. 4 and 5, the connecting member 21 has a narrow strip shape and may be extended and attached along an interface between adjacent primary insulation panels 11.

In addition, even when the primary insulation panel 11 is deformed due to thermal contraction or thermal expansion, the connection member 21 is intermediate to maintain the attachment state of the connection member 21 to the adjacent primary insulation panel 11. The part has the folded part 21a. Accordingly, even if the distance between the adjacent primary insulation panels 11 is increased by the thermal contraction of the primary insulation panel 11, the folded portion 21a can be expanded to absorb the displacement due to the thermal contraction.

On each primary heat insulation panel 11, the secondary heat insulation panel 15 is laminated | stacked and installed. Like the primary insulation panel 11, the secondary insulation panel 15 is preferably made of a material having excellent heat insulation performance while having a certain strength such as polyurethane foam or reinforced polyurethane foam. The secondary heat insulating panel 15 may include a second protective layer 17 laminated and attached to one side of the heat insulating material such as the polyurethane foam described above. The second protective layer 17 may be made of a low temperature steel material such as aluminum, an aluminum alloy, or SUS.

While the primary insulation panels 11 are installed to be in close contact with each other, the secondary insulation panels 15 are installed to be spaced apart from each other at regular intervals. Between the secondary insulating panels 15 spaced apart, a holding member 23 attached to the connecting member 21 by an adhesive tape or the like to hold the connecting member 21 is disposed. The holding member 23 can be made to have a substantially rectangular cross-sectional shape with a heat insulating material of, for example, EPS or the like.

To avoid interference with the folded portion 21a at a position corresponding to the folded portion 21a of the lower surface of the holding member 23, that is, a portion where the folded portion 21a is positioned when stacked on the connecting member 21. For this reason, it is preferable that the concave groove 23a is formed.

On the holding member 23, an elastic member 25 made of a heat insulating material of a material such as flexible EPS or the like is laminated. For example, a silicone sealant may be applied onto the holding member 23 to fix the elastic member 25. These elastic members 25 are provided so as to be in close contact with the side surfaces of the adjacent secondary insulating panels 15, respectively.

As shown in FIGS. 4 and 5, the insulating panel connection structure of the independent liquefied gas tank according to the present invention has a filling space 27 surrounded by a holding member 23 and a pair of elastic members 25. . This filling space 27 is formed successively around the secondary heat insulation panel 15 so that a cross section may have substantially triangular shape.

The pair of elastic members 25 have inclined portions 25a and stepped portions 25b on their side surfaces. The stepped portion 25b has a shape corresponding to the outer shape of the holding member 23 and is formed to be in close contact with the holding member 23 during lamination. The inclined portion 25a allows the above-mentioned filling space 27 to be formed between the adjacent elastic members 25 when the elastic member 25 is installed to be in close contact with the side surface of the secondary heat insulation panel 25. .

The filling space 27 is preferably formed to have a substantially triangular cross section so that the inlet is narrow and the inner space is wide. Polyurethane foam (PUF) may be injected into the filling space 27 to be foamed, and after the PUF injection, the inlet of the filling space 27 may be closed by a metal or silicone sealant.

Although FIG. 4 shows that a substantially triangular PUF member 28 is inserted into the filling space 27 for convenience of illustration, the PUF foamed in the filling space 27 having a substantially triangular shape is shown. It just means that it is roughly triangular in shape. However, according to a modification of the present invention, the PUF member separately molded may be modified to be inserted into the filling space 27 between the elastic members 25.

As described above, according to the present invention, there is provided a heat insulation panel connection structure of an independent liquefied gas tank in which a heat insulation panel attached to the outside of the tank body is formed in a double structure of a first heat insulation panel and a second heat insulation panel.

According to the independent liquefied gas tank having a double insulation layer of the present invention, compared with the conventional independent liquefied gas tank in which the insulation panel is stacked in a single layer, even if the insulation panel is broken, there is a possibility that the liquefied gas, which is a cargo, may leak immediately. have. That is, in the independent liquefied gas tank of the present invention, since the heat insulation panels are stacked in duplicate, there is little possibility that the double heat insulation panels are damaged at the same time.

In addition, the conventional single layer structure of the insulation panel, when the insulation panels are connected to each other, because the airtight work must be carried out in a narrow step space, the operation is difficult and the inspection also had a difficult problem, the dual structure as the present invention is the primary insulation panel After installation, the airtight construction of the connection part can proceed in a large space, the working conditions are good, and inspection can be carried out easily.

In addition, the dual structure of the present invention can more flexibly cope with the situation where the thickness or size adjustment of the heat insulation panel is required to improve the heat insulation performance.

In addition, the single-layer structure of the insulation panel as in the prior art should be re-installed until the airtight construction when replacing the insulation panel due to the external damage of the insulation panel to ensure the airtight, the dual structure of the present invention need to touch the connection structure installed in the primary insulation panel By replacing only the secondary insulation panel without repairing, it is possible to complete the replacement work of the damaged insulation panel, which is easy to maintain.

Insulation structure of the standalone liquefied gas tank according to the present invention can be applied to any of the offshore structures used as floating stand-alone liquefied gas tank, as well as the stand-alone liquefied gas tank is floating in the sea where the flow occurs, again In other words, LNG FPSO (Floating, Production, Storage and Offloading) or LNG FSRU, including liquefied gas carriers carrying LNG, LPG, etc. It can be applied to both offshore plants such as Floating Storage and Regasification Unit.

As described above, the independent liquefied gas tank having a double insulation layer according to the present invention has been described with reference to the illustrated drawings, but the present invention is not limited to the embodiments and drawings described above, and is seen within the claims. Various modifications and variations can be made by those skilled in the art to which the invention pertains.

1 is a partial cross-sectional view of the thermal insulation structure of a standalone liquefied gas tank according to a preferred embodiment of the present invention,

Figure 2 is an exploded cross-sectional view of each component to explain the insulation panel coupling structure of the insulation structure according to the invention,

Figure 3 is a cross-sectional view of the insulation panel coupling structure according to the present invention coupled to the outside of the tank body,

Figure 4 is an exploded cross-sectional view of each component to explain the insulation panel connection structure of the insulation structure according to the invention, and

5 is a cross-sectional view of the insulation panel connection structure according to the present invention coupled to the outside of the tank body.

Description of the Related Art

1: tank body 3: stud bolt

5 fixing member 5a fastening part

5b: extension part 5c: flange part

7: first filling member 8: washer

9: nut 10: heat insulation panel

11: primary insulation panel 12: first hole

12a: step portion 12b: small diameter portion

12c: large diameter portion 13: the first protective layer

15: secondary insulation panel 16: second hole

17: second protective layer 18: bonding plate

18a: through-hole 19: second filling member

21: connection member 21a: folded part

23: holding member 23a: groove portion

25: elastic member 25a: inclined portion

25b: step 27: charging space

Claims (7)

As a standalone liquefied gas tank for storing liquefied gas, A tank body accommodating liquefied gas; A heat insulation layer installed outside the tank body; Including; The insulating layer is a standalone liquefied gas tank, characterized in that formed by stacking a plurality of insulating panels in a double. The method according to claim 1, The plurality of the insulation panel is a standalone liquefied gas tank, characterized in that connected to each other by foam molding the insulation material between the insulation panel and the insulation panel. The method according to claim 1, The heat insulation layer includes a plurality of primary insulation panels stacked on the tank body, and a plurality of secondary insulation panels stacked on each of the primary insulation panels, and the secondary insulation panels include the primary insulation Stand-alone liquefied gas tank, characterized in that smaller than the panel. The method of claim 3, The plurality of primary insulation panels are arranged to be in close contact with each other, an elastic member having a filling space formed therein is disposed between the plurality of secondary insulation panels, the filling space is characterized in that the insulating material is filled Liquefied gas tank. The method of claim 3, A stud bolt is installed outside the tank body, and the independent insulation gas tank is installed on the outside of the tank body through a fixing member coupled to the primary insulation panel and the secondary insulation panel. . The method according to claim 5, The fixing member may include a fastening portion screwed to the stud bolt, an extension portion extending from the fastening portion, and coupled to the secondary heat insulating panel, and in a radial direction to fix the primary heat insulating panel. Stand-alone liquefied gas tank comprising a flange portion which protrudes to be caught on the stepped portion formed in the primary insulation panel. The method of claim 3, In order to connect the primary insulation panels to each other, a connection member is attached on the adjacent primary insulation panels along a boundary of the plurality of primary insulation panels, so that the connection member can remain attached during thermal deformation. Independent liquefied gas tank, characterized in that the folded portion is formed.

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