KR102664942B1 - Insulation Structure of Liquefied Natural Gas storage Tank - Google Patents

Abstract

The insulation structure of a liquefied natural gas storage tank is disclosed. The insulation structure of the liquefied natural gas storage tank according to the present invention is a double barrier structure formed by sequentially stacking a secondary insulation wall, a secondary sealing wall, a primary insulation wall, and a primary sealing wall on the inner wall of the hull. In a gas storage tank, the secondary insulation wall includes a transition area composed of insulation layers having different stiffnesses, and the primary insulation wall includes a boundary portion where insulation layers having different stiffnesses face each other in the secondary insulation wall. By including a lower slit formed in the lower part of the primary insulation wall at the corresponding position, the metal membrane of the sealing wall is prevented from being damaged by the height difference caused by the difference in the amount of heat contraction of the insulation layers with different rigidities during heat contraction by LNG. It has an effective prevention effect.

Description

Insulation structure of liquefied natural gas storage tank {Insulation Structure of Liquefied Natural Gas storage Tank}

The present invention relates to an insulation structure of a liquefied natural gas storage tank, and more specifically, to a liquefied natural gas storage tank that effectively prevents the metal membrane of the sealing wall from being damaged by height differences occurring at the boundaries of insulation layers with different rigidities. It is about insulation structure.

Natural gas is transported in gas form through onshore or offshore gas pipelines, or stored in LNG carriers as liquefied natural gas (Liquefied Natural Gas (LNG)) and transported to distant consumers. LNG is obtained by cooling natural gas to extremely low temperatures (approximately -163°C), and its volume is reduced to approximately 1/600 compared to gaseous natural gas, making it very suitable for long-distance transportation by sea.

Structures for transporting or storing LNG, such as LNG carriers that carry LNG on the sea and unload LNG at land-based destinations, are equipped with storage tanks (commonly referred to as 'cargo holds') that can withstand the extremely low temperatures of LNG.

LNG storage tanks can be classified into independent tank type and membrane type depending on whether the load of the cargo acts directly on the insulation material. Typically, membrane-type storage tanks are divided into GTT's NO 96 type and MARK Ⅲ type, and independent tank-type storage tanks are divided into MOSS type and IHI-SPB type.

Among the membrane-type storage tanks, the NO 96 type storage tank has primary and secondary sealing walls made of an Invar (36% nickel steel) membrane with a thickness of 0.5 to 0.7 mm, and perlite in a plywood box. It includes primary and secondary insulation walls provided in the form of an insulation box filled with insulation materials such as powder.

The NO 96 type storage tank has almost the same level of liquid tightness and strength as the primary sealing wall and the secondary sealing wall, so when the primary sealing wall leaks, the cargo can be safely supported with only the secondary sealing wall for a considerable period of time.

In addition, the NO 96 type storage tank has an insulation wall filled with insulation inside a wooden box, so it can have higher compressive strength and rigidity compared to the MARK Ⅲ type storage tank, and the automation rate is high due to easy welding.

Meanwhile, the MARK Ⅲ type storage tank has a primary sealing wall made of a 1.2mm thick stainless steel (SUS) membrane, a secondary sealing wall made of triplex, and a top surface of polyurethane foam or It includes primary and secondary insulation walls made of insulation panels with wood plywood glued to the bottom.

The primary sealing wall of the MARK III type storage tank has wave-shaped wrinkles to absorb heat contraction caused by LNG in a cryogenic state, and these wave-shaped wrinkles absorb membrane deformation, so no significant stress is generated within the membrane.

However, the MARK Ⅲ type storage tank has the disadvantage of being less stable than the NO 96 type storage tank because it is difficult to apply a stainless steel membrane with a corrugated structure to the secondary sealing wall due to interference with the insulation wall, so it uses a triplex structure.

The MARK Ⅲ type storage tank has a disadvantage in terms of installation/manufacturing due to the low welding automation rate of the primary sealing wall with corrugations, but compared to the Invar membrane, the stainless steel membrane and triplex are cheaper and easier to construct, and polyurethane Because foam has an excellent insulation effect, it is widely used with NO 96 type storage tanks.

The present invention reinforces the support structure of the sealing wall by an Inba steel structure installed at the corner of the liquefied natural gas storage tank, thereby providing the secondary sealing wall with a flat shape while providing the insulation wall with an insulation panel made of polyurethane foam. By making it possible to construct a metal membrane, we aim to provide an insulation structure for a new type of liquefied natural gas storage tank that is different from the conventional NO 96 type storage tank or MARK Ⅲ type storage tank.

In addition, another technical problem to be achieved by the present invention is that, as insulation layers with different stiffnesses are mixed in the corners of the liquefied natural gas storage tank, heat generation occurs at the boundary between insulation layers with different stiffness (insulation box and insulation panel). This effectively prevents the metal membrane of the sealing wall from being damaged by the height difference.

In order to achieve the above object, the present invention provides liquefied natural gas storage with a double barrier structure formed by sequentially stacking a secondary insulation wall, a secondary sealing wall, a primary insulation wall, and a primary sealing wall on the inner wall of the hull. In the tank, the secondary insulation wall includes a transition area composed of insulation layers having different stiffnesses, and the primary insulation wall has insulation layers having different stiffnesses facing each other in the secondary insulation wall. Including a lower slit formed in the lower part of the primary insulation wall at a position corresponding to the boundary portion, the metal membrane of the sealing wall is formed due to a height difference caused by the difference in the amount of heat contraction of the insulation layers with different rigidities during heat contraction by LNG. Provides an insulation structure for liquefied natural gas storage tanks that prevents damage.

The primary insulation wall may further include at least one upper slit formed on an upper portion of the primary insulation wall.

The vertical position of the upper slit may not match the lower slit.

The upper slit may include a pair of upper slits formed at positions spaced apart by the same distance forward and backward in the longitudinal direction of the primary insulation wall from the position where the lower slit is formed.

The sum of the depths of the upper slit and the lower slit may be smaller than the thickness of the primary insulation wall.

The lower slit may be formed within 25 mm on both sides of the boundary where insulation layers with different rigidities face each other in the secondary insulation wall.

The width of the lower slit may be 2 to 30 mm.

In addition, in order to achieve the above object, the present invention is a liquefied natural gas provided in a double barrier structure in which a secondary insulation wall, a secondary sealing wall, a primary insulation wall, and a primary sealing wall are sequentially stacked on the inner wall of the hull. In the storage tank, the secondary insulation wall includes an insulation box disposed at a corner of the storage tank, and a secondary insulation disposed in an area other than the corner of the storage tank and having a different stiffness from the insulation box. It includes a panel, and the primary insulation wall includes a plurality of primary insulation panels disposed on the secondary sealing wall, and is disposed closest to the corner of the storage tank among the plurality of primary insulation panels. The primary insulation panel is arranged to span the top of the insulation box and the secondary insulation panel, and the insulation box and the secondary insulation panel are located at the bottom of the primary insulation panel closest to the corner of the storage tank. It provides an insulation structure for a liquefied natural gas storage tank, characterized in that a lower slit is formed at a position corresponding to the boundary where the insulation panel faces.

The insulation box is provided in the form of a plywood box filled with insulation, and the primary and secondary insulation panels are plywood plywood on at least one of the upper and lower surfaces of polyurethane foam or fiber-reinforced polyurethane foam insulation. This can be provided as a sandwich panel in a glued form.

The lower slit formed in the primary insulation panel disposed at the transverse corner of the storage tank is formed to extend along the transverse direction of the storage tank, and the primary insulation panel disposed at the longitudinal corner of the storage tank The lower slit formed in is formed to extend along the longitudinal direction of the storage tank, and the lower slit formed in the primary insulation panel disposed in the area where the transverse corner portion and the longitudinal corner portion of the storage tank meet is, The lower slit extending along the transverse direction of the storage tank may be formed to intersect with the lower slit extending along the longitudinal direction.

At least one upper slit is formed on the upper part of the primary insulation panel disposed closest to the corner of the storage tank,

The vertical position at which the upper slit is formed may not match the vertical position at which the lower slit is formed.

The upper slit may include a pair of upper slits extending in the same direction as the extending direction of the lower slit and each formed at a position spaced apart from the lower slit by the same distance.

The sum of the depths of the upper slit and the lower slit may be smaller than the thickness of the primary insulation wall.

According to the insulation structure of a new type of liquefied natural gas storage tank provided according to the present invention, automation of welding is possible in installing the secondary sealing wall on the upper part of the secondary insulation wall, thereby improving productivity, and the insulation wall is poly. As it is made of urethane foam, the insulation performance is improved compared to the case where an insulation box is placed as a component of the insulation wall.

In addition, according to the present invention, when arranging an insulation layer (insulation box and insulation panel) with different rigidity for each section at the corner of the liquefied natural gas storage tank, a slit is formed in the lower part of the insulation panel disposed over the top. By forming this, it is possible to effectively prevent the metal membrane of the sealing wall from being damaged by height differences occurring at the boundary between insulation layers (insulation box and insulation panel) with different rigidities.

Figure 1 is a diagram showing the insulation structure of the lateral corner portion of the liquefied natural gas storage tank according to the present invention.
Figure 2 is a diagram showing a primary insulation panel disposed at a transverse corner in a liquefied natural gas storage tank according to the present invention.
Figure 3 is a diagram showing a primary insulation panel disposed at a longitudinal corner in a liquefied natural gas storage tank according to the present invention.
Figure 4 is a view showing the primary insulation panel disposed in the area where the lateral corner portion and the longitudinal corner portion meet in the liquefied natural gas storage tank according to the present invention.
Figure 5 is a diagram for explaining the effect of the insulation structure of the liquefied natural gas storage tank according to the present invention.
Figure 6 is a diagram showing the insulation structure of the lateral corner portion of a liquefied natural gas storage tank according to another embodiment of the present invention.

In order to fully understand the present invention, its operational advantages, and the objectives achieved by practicing the present invention, reference should be made to the accompanying drawings illustrating preferred embodiments of the present invention and the contents described in the accompanying drawings.

Hereinafter, the present invention will be described in detail by explaining preferred embodiments of the present invention with reference to the accompanying drawings. The same reference numerals in each drawing indicate the same member.

In the present invention, the use of the terms 'primary' and 'secondary' refers to whether the function of primarily sealing or insulating LNG, or secondary sealing or insulating, is based on the LNG stored in the storage tank. It was used as a standard for classification.

Additionally, by convention, the terms 'top' or 'above' applied to elements of a tank refer to a direction towards the inside of the tank, regardless of the direction with respect to gravity, and likewise, the terms 'bottom' or 'below' refer to a direction towards the inside of the tank, regardless of the direction with respect to gravity. Regardless of the direction, it points towards the outside of the tank.

Figure 1 is a diagram showing the insulation structure of the horizontal corner of the liquefied natural gas storage tank according to the present invention, and Figure 2 shows the primary insulation panel disposed at the horizontal corner of the liquefied natural gas storage tank according to the present invention. Figure 3 is a diagram showing the primary insulation panel disposed at the longitudinal corner in the liquefied natural gas storage tank according to the present invention, and Figure 4 is a diagram showing the lateral corner and longitudinal in the liquefied natural gas storage tank according to the present invention. A drawing showing the primary insulation panel disposed in the area where the directional corners meet, and Figure 5 is a drawing for explaining the effect of the insulation structure of the liquefied natural gas storage tank according to the present invention.

First, referring to Figure 1, the liquefied natural gas storage tank according to the present invention includes a secondary insulation wall 100 made of a plurality of secondary insulation panels 110 arranged on the inner wall of the hull (H), and a secondary insulation wall 100. A secondary sealing wall 200 installed on the insulation wall 100, a primary insulation wall 300 consisting of a plurality of primary insulation panels 310 arranged on the secondary sealing wall 200, and 1 It can be seen that the structure includes a primary sealing wall 400 installed on the primary insulating wall 300.

The primary insulation panel 310 is manufactured as a unit panel in the shape of a hexahedron or more polyhedron, and a plurality of primary insulation panels 310 are arranged in the horizontal and longitudinal directions on the secondary sealing wall 200, thereby providing the primary insulation panel 310. An insulating wall 300 can be formed.

The secondary insulation panel 110 is similarly manufactured as a unit panel in the shape of a hexahedron or more polyhedron, and a plurality of secondary insulation panels 110 are arranged in the horizontal and longitudinal directions on the inner wall of the hull (H) to provide secondary insulation. A wall 100 can be formed.

The primary and secondary insulation panels (310, 110) are adhesive panels with a protective plate attached to the upper or lower surfaces or both of the upper and lower surfaces of an insulating material such as polyurethane foam (PUF) or fiber-reinforced polyurethane foam (RPUF). It can be provided as a sandwich panel. The protective plate may be made of composite materials such as plywood or fiber reinforced plastic (GRP), and serves to provide mechanical rigidity to the insulation panels 310 and 110.

The secondary insulation wall 100 may be fixed to the inner wall of the hull (H) with an adhesive such as epoxy mastic or studs, and the primary insulation wall 300 may be attached to the secondary insulation wall 100. With the secondary sealing wall 200 interposed between them, the primary insulation panel 310 is coupled to a securing device provided on the upper part of the secondary insulation panel 110, thereby creating a secondary sealing wall ( 200) can be fixed in close contact with the upper part.

The first and second sealing walls 400 and 200 may be made of a metal membrane.

The primary sealing wall 400 and the secondary sealing wall 200 are selectively made of one of various metal materials that are resistant to low-temperature brittleness, such as Invar, stainless steel (SUS), and aluminum alloy. It can be made and can include both flat or corrugated metal membranes.

In the present invention, as a preferred embodiment, the primary sealing wall 400 is made of a corrugated membrane made of stainless steel (SUS), and the secondary sealing wall 200 is made of a flat membrane made of Invar. Provides an insulating structure for the storage tank.

The primary sealing wall 400 is in direct contact with and seals the LNG, and may be made of a stainless steel membrane containing a plurality of corrugations formed toward the inside of the storage tank, and the plurality of corrugations formed on the membrane are Absorbs shrinkage caused by cryogenic temperatures and prevents stress from concentrating.

The secondary sealing wall 200 may be made of a flat invar membrane in a flat shape.

In addition, in the liquefied natural gas storage tank according to the present invention, a structure made of Invar steel may be installed at the corner of the storage tank so that the secondary sealing wall 200 is provided with a flat Invar membrane in a flat shape. .

Typically, flat Invar membranes have a low heat contraction coefficient, so it is not appropriate to use an insulation panel made of polyurethane foam and plywood (or composite material) as an insulation wall. In order to apply a flat Invar membrane, like a conventional NO 96 type storage tank, the insulation wall supporting the membrane must be composed of an insulation box with low heat shrinkage deformation and high rigidity.

However, the present invention installs a transverse connector (500), a structure made of Invar steel, at the corner of the storage tank, so that the secondary insulation wall (100) is made of polyurethane foam (or fiber-reinforced polyurethane foam). It is possible to construct the secondary sealing wall 200 as a flat membrane while being composed of an insulating panel made of .

Specifically, the transverse connector 500 is a grid-shaped structure installed along the edges (transverse corners) of the front and rear walls of the storage tank, and is an anchoring bar with one end provided on the inner wall of the hull. It is fixedly installed at the corner of the storage tank by welding, and the other end supports both ends of the primary sealing wall 400 and the secondary sealing wall 200, thereby transferring various loads applied to them to the hull (H). It plays a role in conveying.

In this way, a portion of the load applied to the primary and secondary sealing walls (400, 200) is transferred to the hull (H) by the transverse connector (500) installed at the corner of the storage tank, thereby eliminating the flat membrane. It is possible to construct the secondary insulation wall 100, which supports the secondary sealing wall 200, from an insulation panel with weaker rigidity than the insulation box.

Therefore, according to the present invention, when installing the secondary sealing wall 200 on the upper part of the secondary insulation wall 100, a welding line can be formed as a straight line, and thus automation of welding is possible, thereby increasing productivity. This has an improving effect.

In addition, in the present invention, as the insulation walls 300 and 100 are made of polyurethane foam (or fiber-reinforced polyurethane foam), insulation performance is also improved. The liquefied natural gas storage tank according to the present invention has the same insulation effect while significantly reducing the thickness of the primary and secondary insulation walls, compared to the conventional NO 96 type storage tank in which the insulation wall is provided in the form of an insulation box. You can reap.

Meanwhile, a highly rigid insulating box 510 may be placed inside the transverse connector 500 and between the transverse connector 500 and the hull (H) to support the transverse connector 500. there is. The insulation box 510 may be prepared by filling the inside of a plywood box with an insulation material such as perlite powder or glass wool.

Here, among the insulation boxes 510, the insulation boxes 510' and 510'' disposed adjacent to the insulation panels 310 and 110 on the side portion of the transverse connector 500 are defined as corner boxes. .

The corner boxes 510' and 510'' include a primary corner box 510' placed at the level of the primary insulation wall 300 and a secondary corner box 510 placed at the level of the secondary insulation wall 100. '').

In addition, among the plurality of primary insulation panels 310, the insulation panel 310' disposed closest to the primary corner box 510' is referred to as the primary border panel, and the plurality of secondary insulation panels are Among 110, the insulation panel 110' disposed closest to the secondary corner box 510'' is defined as a secondary border panel.

In the liquefied natural gas storage tank according to the present invention, the primary insulation panel 310 constituting the primary insulation wall 300 and the secondary insulation panel 110 constituting the secondary insulation wall 100 are arranged to cross each other. For this purpose, the corner boxes 510' and 510'' installed to support the transverse connector 500 may be arranged in steps with their ends offset from each other.

That is, as shown in the drawing, the secondary corner box 510'' may be provided to protrude further outward from the transverse connector 500 than the primary corner box 510', and the primary border panel 310' may be arranged to span the secondary corner box 510'' and the secondary border panel 110'.

The corner insulation structure of the liquefied natural gas storage tank according to the present invention as described above is applied not only to the horizontal corner portion (90° corner portion) of the storage tank, but also to the longitudinal corner portion (135° corner portion) of the storage tank. The same can be applied.

Referring to FIG. 4, an Invar steel structure such as an invar beam (600) is installed at the longitudinal corner of the liquefied natural gas storage tank to reinforce the support structure of the first and second sealing walls (400, 200). It can be installed, and insulation boxes (510', 510'') can be placed to support this Inba steel structure.

Although the structure of the sealing wall is omitted in Figure 4, one corner end of the sealing wall is supported by the transverse connector 500, and the corner end formed in a direction perpendicular to this can be supported by the Invar beam 600. You can see that it is a structure.

As such, the liquefied natural gas storage tank according to the present invention is composed of insulation panels (310, 310', 110, 110') in which most of the insulation walls (300, 100) are made of polyurethane foam (or fiber-reinforced polyurethane foam). However, it has a structure in which insulating boxes 510 are mixed in the corner portion of the storage tank.

However, at this time, the rigidity of the corner boxes (510', 510'') installed at the corners is high, but the rigidity of the border panels (310', 110') is low, so the corner boxes (510', 510'') and the border panels There is a difference in the degree of heat shrinkage (310', 110').

Therefore, during heat contraction by cryogenic LNG, the corner box 510' is damaged due to differences in structural integrity between the corner boxes 510', 510'' and border panels 310', 110', thermal load, and fluid force of liquefied gas. , 510'') and the border panel (310', 110'), a height difference occurs due to heat shrinkage at the boundary, which causes stress in the sealing walls (400, 200) installed on the insulating walls (300, 100). There is a risk of damage to the metal membrane due to concentration.

The present invention relates to the mixing of insulation layers with different rigidities for each section in the corners of a storage tank, thereby forming a gap in the height of the sealing walls 400 and 200 due to a height difference occurring at the boundary between insulation layers with different rigidities (insulation box and insulation panel). In order to prevent the metal membrane from being damaged, as shown in FIG. 1, the primary insulation panel 310' disposed closest to the corner of the storage tank, that is, the lower part of the primary border panel 310'. It provides an insulation structure for a liquefied natural gas storage tank in which the lower slit 311 is formed.

The lower slit 311 is formed at a position corresponding to the boundary between the secondary corner box 510'' and the secondary border panel 110', and serves to relieve stress concentration due to sudden changes at that position.

Referring to FIG. 5, even if a height step occurs due to a difference in rigidity between the secondary corner box 510'' and the secondary border panel 110' during heat shrinkage by cryogenic temperature, the primary border panel 310' It can be seen that the primary sealing wall 400 has a gentle slope due to the lower slit 311 formed at the bottom.

In addition, because the lower part of the first border panel 310' is discontinuously formed by the lower slit 311, a difference in rigidity occurs between the secondary corner box 510'' and the secondary border panel 110'. Since the part that presses the secondary sealing wall 200 at the point is divided, the load acting on the secondary sealing wall 200 at that point has the effect of being distributed.

The lower slit 311 may be formed at a location within 25 mm on both sides of the point where the difference in rigidity occurs, that is, the boundary between the secondary corner box 510'' and the secondary border panel 110'. , the width can be formed from 2 to 30 mm.

A single or plural number of lower slits 311 may be formed in the lower part of the first border panel 310' depending on the arrangement structure of the insulation system.

In the present invention, as shown in FIG. 2, a lower slit 311 extending along the horizontal direction of the storage tank may be formed in the primary border panel 310' disposed at the horizontal corner of the storage tank. As shown in FIG. 3, a lower slit 311 extending along the longitudinal direction of the storage tank may be formed in the primary border panel 310' disposed at a longitudinal corner of the storage tank.

In addition, as shown in FIG. 4, the primary border panel 310' disposed in the area where the horizontal corner and the longitudinal corner of the storage tank meet has a lower slit 311 extending along the horizontal direction of the storage tank. and a lower slit 311 extending along the longitudinal direction may be formed to intersect each other.

Although not shown in the drawing, in addition to the primary border panel 310', a lower slit will be formed in the primary insulation panel 310 located at the upper part of the boundary between the secondary insulation panels 110 adjacent to each other to correspond to the corresponding position. In addition, at least one slit may be formed in the upper part of the secondary insulation panel 110 to relieve stress concentration.

Figure 6 is a diagram showing the insulation structure of the lateral corner portion of a liquefied natural gas storage tank according to another embodiment of the present invention.

Referring to Figure 6, the liquefied natural gas storage tank according to another embodiment of the present invention adopts the structure of the liquefied natural gas storage tank according to the present invention shown in Figures 1 to 5, but has a primary border panel ( It can be seen that a plurality of upper slits 312 are formed together at the upper part of 310').

The upper slit 312 is formed to relieve stress concentration on the upper surface of the primary border panel 310' due to heat contraction due to cryogenic temperatures, and together with the lower slit 311, the primary border panel 310' ) promotes structural safety of the insulation layer by preventing stress concentration.

At least one upper slit 312 may be formed on the upper part of the primary border panel 310', and extends in the same direction as the lower slit 311 extends.

In the present invention, the upper slit 312 may be formed directly above the lower slit 311, but this is preferably avoided. This is because if the upper slit 312 is formed on the same line as the lower slit 311, the panel thickness in the area where the slits 311 and 312 are formed becomes thin and the strength may decrease.

More preferably, the upper slit 312 is a pair of upper slits formed at positions spaced apart by the same distance forward and backward in the longitudinal direction of the primary border panel 310' from the position where the lower slit 311 is formed. It may include a slit (312).

In addition, it is preferable that the sum of the depths of the upper slit 312 and the lower slit 311 is smaller than the thickness of the primary border panel 310'.

Although not shown in the drawing, an upper slit may be formed in the same manner in the primary border panel 310' disposed at the longitudinal corner of the storage tank, and in addition, the primary border panel (310') disposed at the corner of the storage tank 310'), as well as on the general primary insulation panel 310, an upper slit can be formed by preventing stress concentration in the panel.

According to the present invention, in arranging an insulation layer (insulation box and insulation panel) with different rigidity for each section at the corner of a liquefied natural gas storage tank, a slit is formed in the lower part of the insulation panel disposed over the top. , It has the effect of effectively preventing the metal membrane of the sealing wall from being damaged by the height difference that occurs at the boundary between insulation layers (insulation box and insulation panel) with different rigidities.

The present invention is not limited to the described embodiments, and it is obvious to those skilled in the art that various modifications and changes can be made without departing from the spirit and scope of the present invention. Accordingly, such modifications or variations should be considered to fall within the scope of the claims of the present invention.

100: secondary insulation wall 110: secondary insulation panel
110': 2nd border panel
200: secondary sealing wall
300: Primary insulation wall 310: Primary insulation panel
310': 1st border panel 311: lower slit
312: upper slit
400: Primary sealing wall
500: Transverse connector 510: Insulation box
510': 1st corner box 510'': 2nd corner box
600: Invar beam

Claims (13)

delete delete delete delete delete delete delete In a liquefied natural gas storage tank provided with a double barrier structure in which a secondary insulation wall, a secondary sealing wall, a primary insulation wall, and a primary sealing wall are sequentially stacked on the inner wall of the hull,
The secondary insulation wall includes a secondary corner box disposed at a corner of the storage tank, and a secondary insulation panel disposed in an area other than the corner of the storage tank and having a different stiffness from the secondary corner box. Including,
The primary insulation wall includes a primary corner box disposed at a corner of the storage tank and a plurality of primary insulation panels disposed on the secondary sealing wall,
Among the plurality of primary insulation panels, the primary border panel disposed closest to the corner of the storage tank is arranged to span the secondary corner box and the upper part of the secondary insulation panel,
A lower slit is formed in the lower part of the first border panel at a position corresponding to the boundary where the secondary corner box and the secondary insulation panel face each other,
An upper slit is formed on the upper part of the primary border panel closest to the corner of the storage tank, and the upper slit extends in the same direction as the lower slit.
The upper slit is characterized in that it consists of a pair, each formed at a position spaced apart from the lower slit by the same distance.
Insulation structure of a liquefied natural gas storage tank. In claim 8,
The secondary corner box is provided in the form of a plywood box filled with insulation material,
The primary and secondary insulation panels are characterized in that they are provided as sandwich panels in which plywood plywood is bonded to at least one of the upper and lower surfaces of polyurethane foam or fiber-reinforced polyurethane foam insulation,
Insulation structure of a liquefied natural gas storage tank. In claim 9,
The lower slit formed in the primary insulation panel disposed at the transverse corner of the storage tank is formed to extend along the transverse direction of the storage tank,
The lower slit formed in the primary insulation panel disposed at the longitudinal corner of the storage tank is formed to extend along the longitudinal direction of the storage tank,
The lower slit formed in the primary insulation panel disposed in the area where the transverse corner portion and the longitudinal corner portion of the storage tank meet includes a lower slit extending along the transverse direction of the storage tank and a lower slit extending along the longitudinal direction. Characterized by being formed in an intersecting form,
Insulation structure of a liquefied natural gas storage tank. delete In claim 8,
It is installed at a corner of the storage tank and further includes a transverse connector coupled to the inner wall of the hull,
One end of the transverse connector is fixed to a corner of the storage tank, and the other end of the transverse connector supports both ends of the primary sealing wall and the secondary sealing wall,
Characterized in that the transverse connector is supported by the secondary corner box,
Insulation structure of a liquefied natural gas storage tank. In claim 8,
The sum of the depths of the upper slit and the lower slit is less than the thickness of the primary insulation wall,
Insulation structure of a liquefied natural gas storage tank.

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