KR20230003671A - Insulation structure of cargo tank - Google Patents

Abstract

Disclosed is an insulation structure for a liquefied gas storage tank with improved structural stability. According to one embodiment of the present invention, an insulation structure for a liquefied gas storage tank comprises: a foam insulation layer covering the outer surface of the storage tank for accommodating liquefied gas; a plurality of barriers provided to surround the outside of the foam insulation layer; a plurality of supports for supporting the plurality of barriers by separating the plurality of barriers from the outer surface of the foam insulation layer; and a powder insulator filled in a space between the outer surface of the foam insulation layer and the inner surface of the plurality of barriers. Each barrier may be provided with one side curved concavely toward the storage tank.

Description

Insulation structure of liquefied gas storage tank {INSULATION STRUCTURE OF CARGO TANK}

The present invention relates to a heat insulating structure of a liquefied gas storage tank, and more particularly, to a heat insulating structure of a liquefied gas storage tank capable of effectively insulating low-temperature liquefied gas to promote stable accommodation and storage.

Liquefied gas is made into a liquid by cooling or compressing a gas, and is a phase change to a liquid by cooling a gas at room temperature for the convenience of transportation and storage. One of the widely used and important resources among liquefied gases is liquefied natural gas (LNG). Liquefied natural gas refers to a colorless and transparent ultra-low temperature liquid that reduces the volume to 1/600 by cooling natural gas, whose main component is methane, to about -162 ° C.

Recently, as liquefied natural gas is used as an important energy resource, efficient transportation methods capable of transporting liquefied natural gas in large quantities from production areas to various demand areas have been reviewed. As part of these efforts, a liquefied gas transport ship capable of transporting a large amount of liquefied natural gas through the sea has been developed.

A liquefied gas storage tank capable of withstanding cryogenic temperatures is installed in a liquefied gas transport vessel to store and store liquefied natural gas. Since liquefied natural gas has a vapor pressure higher than atmospheric pressure and has a boiling temperature of ultra-low temperature, the liquefied gas storage tank must be made of a material that can withstand ultra-low temperatures, and has a unique insulation structure that is resistant to other thermal stress and heat shrinkage and can prevent heat intrusion. will need

Storage tanks are classified into independent type and membrane type depending on whether the cargo load is directly applied to the insulation structure. Among them, the independent storage tank has a relatively simple structure and can stably accommodate liquefied natural gas, so it is adopted and used in various liquefied gas transport ships. In the stand-alone storage tank, a storage tank is installed in a storage tank accommodation space formed on the hull of a floating offshore structure such as a ship structurally, and an insulation structure is installed between the outer surface of the storage tank and the storage tank accommodation space.

At this time, when a storage tank with a large specification is adopted in order to increase the loading capacity of the storage tank, the space between the outer surface of the storage tank and the storage tank accommodation space is narrowed, making it difficult to install the insulation structure. In addition, when a relatively thick insulation structure is adopted to improve insulation performance, or when the distance between the outer surface of the storage tank and the storage tank receiving space is widened to facilitate the installation of the insulation structure, a storage tank with a small size specification Since it must be adopted, there is a problem in that the loading amount of the storage tank is reduced.

Accordingly, studies are required to effectively insulate the low-temperature liquefied gas such as liquefied natural gas loaded in the storage tank to stably accommodate and store the liquefied gas, and to increase the liquefied gas load in the storage tank.

Republic of Korea Patent Publication No. 10-2008-0097519 (published on November 6, 2008)

This embodiment is intended to provide a thermal insulation structure of a liquefied gas storage tank with improved structural stability.

This embodiment is to provide a heat insulation structure for a liquefied gas storage tank with improved assembly and productivity.

This embodiment is to provide a heat insulation structure of a liquefied gas storage tank that can effectively insulate the loaded liquefied gas.

This embodiment is to provide a heat insulation structure of a liquefied gas storage tank that can be quickly and easily installed.

The present embodiment is to provide a thermal insulation structure of a liquefied gas storage tank capable of increasing the loading of the liquefied gas in the storage tank while stably insulating the liquefied gas.

The present embodiment is intended to provide a thermal insulation structure for a liquefied gas storage tank that can improve space utilization of a floating offshore structure such as a ship in which the storage tank is installed.

The present embodiment is to provide a heat insulation structure of a liquefied gas storage tank that can prevent leakage of liquefied gas and safety accidents caused by leakage of liquefied gas.

This embodiment is intended to provide a heat insulation structure of a liquefied gas storage tank that can promote operational efficiency with a simple structure.

According to one aspect of the present invention, the foam insulation layer covering the outer surface of the storage tank for accommodating liquefied gas; a plurality of barriers provided to surround the outside of the foam insulation layer; a plurality of supports for supporting the plurality of barrier walls by separating them from the outer surface of the foam insulation layer; and a powder insulator filled in a spaced space between an outer surface of the foam insulation layer and an inner surface of the plurality of barrier walls, wherein each of the barrier walls protrudes outward and has a cavity formed therein to accommodate the powder insulator to accommodate the powder. A heat insulating structure of a liquefied gas storage tank having a part may be provided.

A part of the powder insulation is provided with an insulation structure of a liquefied gas storage tank that moves from the spaced space to the cavity by thermal expansion of the storage tank and moves from the cavity to the spaced space by thermal contraction of the storage tank. It can be.

An insulating structure of a liquefied gas storage tank provided in the form of a plurality of protrusions curved outwardly of the powder receiving portion may be provided.

The powder receiving portion may be provided with an insulation structure of a liquefied gas storage tank provided in a corrugated form parallel to the longitudinal direction of the support.

The powder accommodating part is an insulation of a liquefied gas storage tank having an accumulator for temporarily storing the powder insulator in the cavity or discharging the powder insulator from the cavity according to a pressure change of the powder insulator due to thermal deformation of the storage tank. A structure may be provided.

The insulation structure of the liquefied gas storage tank may further include a leakage channel formed on the inner surface of the foam insulation layer in contact with the outer surface of the storage tank and provided as a passage through which liquefied gas leaking from the storage tank moves.

The heat insulating structure of the liquefied gas storage tank according to the present embodiment has an effect of improving structural stability.

The heat insulation structure of the liquefied gas storage tank according to the present embodiment has an effect of improving assemblyability and productivity.

The insulation structure of the liquefied gas storage tank according to the present embodiment has an effect of promoting stable handling of the liquefied gas by effectively insulating the loaded liquefied gas.

The heat insulation structure of the liquefied gas storage tank according to this embodiment has the effect of quickly and easily performing the installation work.

The heat insulation structure of the liquefied gas storage tank according to the present embodiment has an effect of increasing the loading capacity of the liquefied gas storage tank while stably insulating the liquefied gas.

The insulation structure of the liquefied gas storage tank according to the present embodiment has an effect of improving space utilization of floating offshore structures such as ships in which the storage tank is installed.

The heat insulation structure of the liquefied gas storage tank according to the present embodiment has an effect of preventing leakage of liquefied gas and preventing safety accidents caused by leakage of liquefied gas in advance.

The insulation structure of the liquefied gas storage tank according to the present embodiment has an effect of improving operational efficiency as a simple structure.

1 is a side cross-sectional view showing a thermal insulation structure of a liquefied gas storage tank according to a first embodiment of the present invention.
Figure 2 is a perspective view partially cut away of the heat insulation structure of the liquefied gas storage tank according to the first embodiment of the present invention.
FIG. 3 is an enlarged view of part A of FIG. 1 .
FIG. 4 is an enlarged view of portion A during thermal expansion of the liquefied gas storage tank of FIG. 1 .
FIG. 5 is an enlarged view of portion A during thermal contraction of the liquefied gas storage tank of FIG. 1 .
6 is an enlarged cross-sectional view of a heat insulation structure of a liquefied gas storage tank according to a second embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following examples are presented to sufficiently convey the spirit of the present invention to those skilled in the art. The present invention may be embodied in other forms without being limited to only the embodiments presented herein. In the drawings, in order to clarify the present invention, illustration of parts irrelevant to the description may be omitted, and the size of components may be slightly exaggerated to aid understanding.

1 is a lateral cross-sectional view showing an insulation structure 100 of a liquefied gas storage tank according to a first embodiment of the present invention.

The liquefied gas accommodated in the liquefied gas storage tank 10 according to this embodiment may be liquefied natural gas phase-changed into a cryogenic liquid for the convenience of transportation and storage. However, it is not limited to this, and if liquefied ethane gas, liquefied hydrocarbon gas, liquefied propane gas, liquefied hydrogen gas, etc. are cooled to a low temperature and liquefied, and then shipped and handled inside the storage tank 10, it should be understood the same as the same technical concept. do.

In addition, referring to FIG. 1 , the storage tank 10 to which the heat insulating structure 100 according to the present embodiment is applied may be mounted on floating offshore structures 1 of various types and methods. For example, the floating offshore structure 1 may be composed of a liquefied gas carrier, FPSO (Floating Production Storage and offloading), LNG FSRU (Floating Storage and Regasification Unit), etc., and needs to accommodate and store low-temperature liquefied gas It can be applied to the hull (1) of various offshore structures.

The hull 1 of the floating offshore structure may be composed of a double hull structure composed of an outer plate and an inner plate, and the inside of the hull 1 includes a storage tank 10, a support structure 20, and an insulation structure to be described later. A storage tank accommodating space 2 in which the 100 or the like is installed and disposed may be formed. The storage tank accommodating space 2 may be partitioned by an inner wall of the hull 1, and the storage tank 10 may be fixed and supported inside the storage tank accommodating space 2 by the support structure 20.

The storage tank 10 is provided to accommodate and store liquefied natural gas therein, and may be fixed and supported by a plurality of support structures 20 and disposed inside the storage tank accommodating space 2 . The storage tank 10 may be made of an independent type tank in which the load of the liquefied natural gas loaded therein directly acts on the inner surface of the storage tank 10 rather than the insulation structure 100, aluminum steel, stainless steel And it can be made of special steel for cryogenic use, such as 35% nickel steel. A plurality of longitudinal partition walls 11 may be provided on the inner surface or inner wall of the storage tank 10 to reinforce the rigidity of the storage tank 10 and to distribute the load acting by the liquefied natural gas accommodated therein. The longitudinal partition wall 11 may extend inwardly from the inner surface or the inner wall of the storage tank 10, and may extend to both sides at an inner end thereof so that its cross section may be formed in a 'T' shape. A supporting partition wall 161 to be described later may protrude outward at a portion where the longitudinal partition wall 11 and the storage tank 10 come into contact, and a detailed description thereof will be described later. In addition, on the upper side of the storage tank 10, a liquid dome (not shown) is installed with various pipes for supplying liquefied natural gas to the inside of the storage tank 10 or unloading liquefied natural gas from the storage tank 10. this can be provided.

A plurality of support structures 20 are distributed at regular intervals between the inner wall of the hull 1 and the outer surface of the storage tank 10 to stably fix and support the storage tank 10 in the storage tank receiving space 2. It can be arranged and provided. For example, as shown in FIG. 1 , a plurality of support structures 20 may be disposed on the top, bottom, and top of the outer surface of the storage tank 10, respectively, but are not limited to the number and location. The support structure 20 stably endures the load of the storage tank 10 and the liquefied natural gas accommodated therein, while the cold heat of the liquefied natural gas is transferred to the storage tank receiving space 2 or external heat is transferred to the storage tank 10. It may be made of a material such as plywood having low thermal conductivity so as not to be transmitted to the inside.

An insulating structure 100 is provided on the outer surface of the storage tank 10 to insulate the liquefied natural gas accommodated in the storage tank 10 from external heat.

Figure 2 is a perspective view of a partial cutaway of the insulation structure of the liquefied gas storage tank according to the first embodiment of the present invention, Figure 3 is an enlarged view of part A of Figure 1, Figure 4 is the liquefied gas of Figure 1 It is an enlarged view of part A during thermal expansion of the storage tank, and FIG. 5 is an enlarged view of part A during thermal contraction of the liquefied gas storage tank of FIG. 1 .

1 to 5, the heat insulation structure 100 of the liquefied gas storage tank according to the first embodiment of the present invention includes a foam insulation layer 110 covering the outer surface of the storage tank 10 in which the liquefied gas is accommodated. , A leak channel 120 formed on the inner surface of the foam insulation layer 110 to be recessed or hollow, through which liquefied gas leaking into the storage tank 10 moves, and a plurality of barrier walls 130 provided on the outside of the foam insulation layer 110 , a plurality of supports 140 supporting the plurality of barrier walls 130 in a state of being spaced apart from the outer surface of the foam insulation layer 110, and a powder insulation material 150 filled between the foam insulation layer 110 and the plurality of barrier walls 130 It can be provided including.

The foam insulation layer 110 may be provided to cover the outer surface of the storage tank 10 . The foam insulation layer 110 may include polyurethane having heat insulation or heat preservation properties, and may be provided by spraying or coating the outer surface of the storage tank 10 using a spray gun or the like. The foam insulation layer 110 sprayed or applied to the outer surface of the storage tank 10 adheres to the outer surface of the storage tank 10 and expands. foam) can be semi-permanently fixed and placed on the outer surface of the storage tank 10.

Between the outer surface of the storage tank 10 and the inner surface of the foam insulation layer 110, a leakage channel 120 provided as a passage through which liquefied natural gas leaked from the storage tank 10 moves may be provided.

The leakage channel 120 may be recessed on the inner surface of the foam insulation layer 110 in contact with the outer surface of the storage tank 10, or may be hollow by removing at least a portion thereof. In addition, the leakage channel 120 stably collects the leakage liquid generated in various parts of the storage tank 10 and guides it to the drip tray T disposed below the storage tank 10. ) It may be formed in a lattice shape or mesh shape on the inner surface of. The leak channel 120 is densely formed on the outer surface of the storage tank 10 to connect and communicate with each other, and at the same time extends toward the drip tray T disposed below the storage tank 10 to flow into the leak channel 120. The leaked liquid of the liquefied natural gas may be moved to and collected in the drip tray T by its own weight.

The leakage channel 120 may be provided using a fiber material (Fiber, 121). After the fiber material 121 is first applied in a grid or mesh shape on the outer surface of the storage tank 10, the above-described foam insulation layer 110 is subsequently formed on the outer surface of the storage tank 10, thereby forming a leakage channel. (120) can be formed. The fiber material 121 may be provided with various types of fibers that sublimate or vaporize when heated. Accordingly, the leak channel 120 may be formed by heating and sublimating or vaporizing the fiber material 121 by receiving the heat of the foam insulation layer 110 that is subsequently sprayed and applied. Alternatively, the fiber material 121 may be provided with a fiber having a property of shrinking when heated, and is heated by the foam insulation layer 110 that is subsequently sprayed and applied, and the fiber material 121 shrinks, thereby reducing the leakage channel 120. may be formed.

A plurality of barrier walls 130 are disposed on the outside of the foam insulation layer 110 to surround the foam insulation layer 110, and are supported at a predetermined distance from the outer surface of the foam insulation layer 110 by a support 140 described below. It can be. A powder insulator 150 described below may be filled in the separation space G formed between the outer surface of the foam insulation layer 110 and the inner surface of the barrier 130 .

The plurality of barriers 130 may be fixed and supported on the outer surface of the support 140 to be described later, and each barrier 130 is fastened or bonded to the support 140 or between unit barriers 130 adjacent to each other. By being fixed by overlap welding, the separation space (G) in which the powder insulator 150 is filled inside can be sealed from the outside. The plurality of barriers 130 may be made of various materials as long as they can stably accommodate and hold the powder insulator 150, but even when cryogenic liquefied natural gas leaks, stable through the same thermal expansion as the storage tank 10 It may be made of the same material as the storage tank 10 such as aluminum steel, stainless steel and 35% nickel steel to enable operation.

Each of the barriers 130 may have one side curved concavely towards the storage tank 10 .

The barrier 130 includes a concave portion 131 curved concavely toward the storage tank 10, and a pair of seating portions extending from the concave portion 131 to both sides and coupled to two adjacent supports 140, respectively. (132).

The concave portion 131 may be disposed between two adjacent supports 140 and formed parallel to the longitudinal direction of the supports 140 . More specifically, the concave portion 131 may be curved so that the central portion is recessed between the two adjacent supports 140 so that the central portion is closest to the storage tank 10 .

The pair of seating parts 132 extend horizontally from the concave part 131 to both sides and are supported by two adjacent supports 140, respectively, and at the same time fastened or bonded to the top of each support 140. can

Accordingly, the central portion of the barrier 130 of the present invention is formed concavely, thereby preventing the central portion of the barrier 130 from protruding convexly due to excessive injection of the powder insulator 150 . In other words, the present invention prevents excessive injection of the powder insulator 150 by providing the barrier 130 with the concave portion 131, and structurally improves the barrier 130 and the support 140 by the injection of the powder insulator 150. deformation can be prevented.

In addition, the barrier 130 of the present invention can play a role of buffering the pressure acting on the powder insulator 150 by being deformed in response to thermal deformation of the storage tank 10 .

For example, when the storage tank 10 thermally expands, the outer wall of the storage tank 10 expands outward, thereby reducing the separation space G and increasing the pressure applied to the powder insulator 150. At this time, the concave portion 131 of the barrier 130 is deformed in a direction to buffer the pressure acting on the powder insulator 150, that is, in a direction in which the radius of curvature of the concave portion 131 increases, so that the pressure of the powder insulator 150 increases. can withstand (see Figure 4).

Conversely, when the storage tank 10 is thermally shrunk, the outer wall of the storage tank 10 is reduced inwardly, so that the separation space G is expanded and the pressure applied to the powder insulator 150 is lowered. At this time, the concave portion 131 of the barrier wall 130 is deformed in a direction of buffering the negative pressure acting on the powder insulator 150, that is, in a direction in which the radius of curvature of the concave portion 131 decreases, so that the powder insulator 150 Can withstand negative pressure. This is to allow the negative pressure acting on the powder insulator 150 while the barrier 130, which was elastically deformed by the pressure when the powder insulator 150 is injected, is elastically restored by the negative pressure of the powder insulator 150. (FIG. 5 Reference)

A plurality of supports 140 may be provided to support the barrier 130 by separating it from the outer surface of the foam insulation layer 110 . A plurality of supports 140 may be formed to extend along the longitudinal direction of the storage tank 10 for stable installation and support of the barrier 130, and each support 140 extends from the outer surface of the storage tank 10 to the outside. It may include a vertical portion 141 extending in a direction and a horizontal portion 142 extending or expanding from an outer end of the vertical portion 141 to both sides. That is, the cross-sectional shape of the support 140 may be provided in a 'T' shape.

The barrier 130 is supported at a predetermined distance from the outer surface of the foam insulation layer 110 by the vertical portion 141 of the support 140, so that the powder is placed between the outer surface of the foam insulation layer 110 and the inner surface of the barrier 130. A separation space G filled with the heat insulating material 150 may be formed. In addition, the barrier 130 is installed in contact with the outer surface of the horizontal portion 142 extending in the lateral direction from the vertical portion 141, so that the support area of the barrier 130 increases, so that the plurality of barriers 130 are formed. It can be fixed and supported more stably. More specifically, the outer surface of the horizontal portion 142 can maintain a stable structure by fixing and supporting the seating portion 132 of the barrier 130.

The inner end of the support 140 may be fixed and supported by a stud bolt 160 fixed to the storage tank 10 by welding or the like, and at least a part of the inner end is inserted into the foam insulation layer 110 to additionally can be supported In addition, the support 140 may be provided by including a polyurethane foam having insulation or heat retention so that external heat is not transferred to the liquefied natural gas inside the storage tank 10 through the support 140.

The powder insulator 150 is filled in the separation space G formed between the outer surface of the foam insulation layer 110 and the inner surface of the barrier 130 to insulate the liquefied natural gas accommodated in the storage tank 10. The powder insulator 150 is preferably filled in the separation space (G) and filled in a part of the cavity (C). The powder insulator 150 is configured in the form of an independent powder and can be provided by filling the space between the outer surface of the foam insulation layer 110 and the inner surface of the barrier 130 by a filling pump (not shown) or the like. The powder insulator 150 may include at least one of glass bubbles and perlite having excellent thermal insulation properties. In this way, the structure of the liquefied gas storage tank 10 can be simplified because the powder insulator 150 in powder form can be quickly filled instead of stacking and installing a separate insulation layer on the storage tank 10, , the time consumed in manufacturing and installation can be reduced.

On the other hand, although not shown in the drawing, for structural stability of the liquefied gas storage tank 10, the separation space G between the outer surface of the foam insulation layer 110 and the inner surface of the barrier 130 is filled with the powder insulation material 150 Inert gas can be continuously supplied and discharged by an air pump (not shown), and a gas detector (not shown) is provided on a required position of the heat insulating structure 100 to detect leakage of liquefied natural gas. .

Hereinafter, the heat insulation structure of the liquefied gas storage tank according to the second embodiment of the present invention will be described.

6 is an enlarged cross-sectional view of a heat insulation structure of a liquefied gas storage tank according to a second embodiment of the present invention.

Referring to FIG. 6, the heat insulation structure 200 of the liquefied gas storage tank according to the second embodiment of the present invention includes a foam insulation layer 110 covering the outer surface of the storage tank 10 in which liquefied gas is accommodated, and a foam insulation layer. A plurality of barriers 130 provided to surround the outer side of (110), a plurality of supports 240 supporting the plurality of barriers 130 while being spaced apart from the outer surface of the foam insulation layer 110, and a foam insulation layer 110 And it may be provided, including a powder insulator 150 filled between the plurality of barriers (130).

Among the descriptions of the insulation structure 200 of the liquefied gas storage tank according to the second embodiment of the present invention described below, liquefaction according to the first embodiment of the present invention described above except for the case of additional description with separate reference numerals. It is the same as the description of the insulation structure 100 of the gas storage tank, and the description is omitted to prevent duplication of contents.

A plurality of supports 240 may be provided to support the barrier 130 by separating it from the outer surface of the storage tank 10 . A plurality of supports 240 may be formed extending along the length of the storage tank 10 for stable installation and support of the barrier 130, and each support 240 extends from the outer surface of the storage tank 10 to the outside. It may include a vertical portion 241 extending in a direction, and a horizontal portion 242 extending or expanding from an outer end of the vertical portion 241 to both sides. That is, the cross-sectional shape of the support 240 may be provided in a 'T' shape. In addition, a seating groove 243 may be formed on the outer surface of the horizontal portion 242 so that the seating portion 132 of the barrier 130 is inserted and supported.

More specifically, at both ends of the horizontal portion 242 of the support 240, seating grooves 243 for accommodating and supporting the seating portion 132 may be recessed along the longitudinal direction of the support 240.

Accordingly, the support 240 has the advantage of being able to prevent and support the deformation of the barrier 130 by supporting the barrier 130 in vertical and horizontal directions by inserting the mounting portion 132 into the mounting groove 243. . Specifically, when the pressure of the powder insulator increases due to the thermal expansion of the storage tank, the concave portion 131 receives a force in the direction in which it spreads. It has the advantage of maintaining its structure.

The present invention has been described with reference to an embodiment shown in the accompanying drawings, but this is only exemplary, and those skilled in the art can make various modifications and equivalent other embodiments therefrom. You will understand. Therefore, the true scope of the present invention should be defined only by the appended claims.

100, 200: insulation structure
110: foam insulation layer 120: leakage channel
121: fiber material 130: barrier
131: concave portion 132: seating portion
140,240: support 141,241: vertical part
142,242: horizontal part 150: powder insulation
243: seating groove

Claims (6)

A foam insulation layer covering the outer surface of the storage tank for accommodating liquefied gas;
a plurality of barriers provided to surround the outside of the foam insulation layer;
a plurality of supports for supporting the plurality of barrier walls by separating them from the outer surface of the foam insulation layer; and
Including a powder insulating material filled in the space between the outer surface of the foam insulation layer and the inner surface of the plurality of barriers,
Each of the barriers
A thermal insulation structure of a liquefied gas storage tank in which one side is formed concavely curved toward the storage tank. According to claim 1,
Each of the barriers
A thermal insulation structure for a liquefied gas storage tank comprising a concave portion curved toward the storage tank and a pair of seating portions extending from the concave portion to both sides and coupled to adjacent supports among the plurality of supports. According to claim 2,
The concave part
Insulation structure of a liquefied gas storage tank curved in parallel with the longitudinal direction of the support. According to claim 2,
each of the supports
A vertical portion extending outwardly of the storage tank and a horizontal portion extending to both sides from an outer end of the vertical portion,
The pair of mounting parts
The insulation structure of the liquefied gas storage tank fixed and supported on the outer surface of the horizontal portion provided on the adjacent support, respectively. According to claim 4,
the horizontal part
A seating groove in which at least a portion is recessed on the outer surface,
the attachment part
A heat insulation structure of a liquefied gas storage tank fixed and supported on the seating groove. According to claims 1 to 5,
The insulation structure of the liquefied gas storage tank further comprising a leakage channel formed on an inner surface of the foam insulation layer in contact with the outer surface of the storage tank and provided as a passage through which liquefied gas leaking from the storage tank moves.

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