KR102614525B1 - Insulation System of Liquefied Natural Gas Storage Tank - Google Patents

Abstract

The present invention relates to an insulation system for an LNG storage tank that includes a liquid dome formed at the top of the rear side in the stern direction, comprising: a sealing wall made of a metal membrane to seal the LNG stored in the LNG storage tank; and an insulating wall installed on the outside of the sealing wall to insulate the LNG, wherein the insulating wall includes an insulating box filled with an insulating material inside a plywood box; And an insulation panel in the form of a protective plate made of plywood or fiber-reinforced plastic is attached to at least one of the upper and lower surfaces of the polyurethane foam as a component, and is installed around the edge of the inner wall of the LNG storage tank and around the liquid dome. Accordingly, an insulation box is placed, and an insulation panel is placed in an area other than the area where the insulation box is placed on the inner wall of the LNG storage tank, but the insulation wall formed between the liquid dome and the rear wall of the LNG storage tank is of the insulation panel. It is composed only of a combination of insulation boxes without arrangement, and the insulation panels arranged adjacent to each other on the insulation wall have a bridge structure in which the upper surfaces are connected to each other by a bridge plate, and are placed between the liquid dome and the rear wall of the LNG storage tank. An insulation system for an LNG storage tank is provided, characterized in that a bridge structure is not applied between insulation boxes.

Description

Insulation System of LNG Storage Tank {Insulation System of Liquefied Natural Gas Storage Tank}

The present invention relates to an insulation system for an LNG storage tank, and more specifically, to an insulation system in which the primary and secondary insulation walls are provided with a panel-type insulation layer made of polyurethane foam, and the secondary sealing wall is composed of a flat invar membrane. This is possible, and it relates to an insulation system for an LNG storage tank that seeks to improve productivity by simplifying the insulation structure around the liquid dome as much as possible.

Natural gas is transported in gaseous 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 of that of 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 rigid triplex, and a polyurethane foam. It includes primary and secondary insulation walls made of insulation panels bonded to plywood plywood on the upper or lower surface.

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, in the MARK Ⅲ type storage tank, it is difficult to apply a corrugated stainless steel membrane as the secondary sealing wall due to interference with the insulation walls placed above and below, and it is also an insulation panel that forms an insulation layer using a combination of polyurethane foam and plywood. Due to the characteristics of the NO 96 type storage tank, it is difficult to apply an Invar membrane with a small heat contraction coefficient, so triplex is usually used instead of a metal membrane, but this structure has the disadvantage of being less stable than the NO 96 type storage tank. there is.

In addition, 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. Because polyurethane foam has excellent insulation effects, it is widely used with NO 96 type storage tanks.

Accordingly, the technical problem to be achieved by the present invention is completely different from the prior art in which the primary and secondary insulation walls of an LNG storage tank are provided with a panel-type insulation layer made of polyurethane foam, and the secondary sealing wall is constructed with a metal membrane. The goal is to provide an insulation system for another new type of LNG storage tank.

In addition, in providing a new type of LNG storage tank insulation system, another technical task is to improve productivity in the construction of the LNG storage tank by simplifying the insulation structure around the liquid dome provided in the LNG storage tank as much as possible. Do this.

In order to achieve the above object, the present invention provides an insulation system for an LNG storage tank including a liquid dome formed on the upper part of the rear side in the stern direction, which is made of a metal membrane and is stored in the LNG storage tank. A sealing wall that seals the LNG; and an insulating wall installed outside the sealing wall to insulate the LNG, wherein the insulating wall includes an insulating box filled with an insulating material inside a plywood box; And an insulation panel in the form of a protective plate made of plywood or fiber-reinforced plastic attached to at least one of the upper and lower surfaces of the polyurethane foam as a component, and around the edge of the inner wall of the LNG storage tank and of the liquid dome. The insulation box is disposed along the periphery, and the insulation panel is disposed in areas other than the area where the insulation box is placed on the inner wall of the LNG storage tank, and is formed between the liquid dome and the rear wall of the LNG storage tank. The insulation wall is made up of only a combination of the insulation boxes without the arrangement of the insulation panels, and the insulation panels arranged adjacent to each other in the insulation wall have a bridge structure in which the upper surfaces are connected to each other by a bridge plate, An insulation system for an LNG storage tank is provided, wherein the bridge structure is not applied between the liquid dome and the insulation box disposed between the rear wall of the LNG storage tank.

The bridge structure can also be applied between the insulation box and the insulation panel arranged adjacent to each other.

The bridge structure may be provided in a structure in which adjacent insulation panels or adjacent insulation panels and insulation boxes are connected by a bridge plate.

The bridge plate is seated across a step formed around the upper edge of one of the insulation panels and a step formed around the upper edge of the insulation panel or insulation box adjacent to the one of the insulation panels, The upper surface of any of the above insulation panels and the neighboring insulation panel or insulation box may be connected.

The sealing wall includes: a primary sealing wall that primarily seals the LNG; and a secondary sealing wall that secondarily seals the LNG, wherein the insulating wall includes: a primary insulating wall disposed between the primary sealing wall and the secondary sealing wall; And a secondary insulation wall disposed between the secondary sealing wall and the inner wall of the hull, wherein the secondary insulation wall formed in the space between the liquid dome and the rear wall of the LNG storage tank is It consists of a single or a plurality of secondary insulation boxes arranged along the longitudinal direction, and the primary insulation wall formed in the space between the liquid dome and the rear wall of the LNG storage tank extends in the longitudinal direction of the LNG storage tank. Accordingly, a plurality of primary insulation boxes are arranged and configured, and the primary insulation boxes and the secondary insulation boxes may be arranged to intersect.

Boundaries between neighboring primary insulation boxes may be arranged to be offset from ends of the secondary insulation boxes.

The insulation system for an LNG storage tank according to the present invention is a conventional method in which the primary and secondary insulation walls of the LNG storage tank are provided with a panel-type insulation layer made of polyurethane foam, and the secondary sealing wall is constructed with a metal membrane. provides a completely new type of LNG storage tank insulation system.

Accordingly, the present invention makes it possible to construct both the primary and secondary insulation walls with an insulation panel made of polyurethane foam while providing both the primary and secondary sealing walls with a metal membrane, thereby improving insulation performance and improving stability. There is an improving effect.

In addition, in the present invention, as the flat Invar membrane is applied as the secondary sealing wall, the welding line is formed straight when installing the secondary sealing wall, so automation of welding is possible and productivity is improved.

In addition, in the insulation system of the LNG storage tank according to the present invention, the primary insulation wall and the secondary insulation wall are arranged across each other, and the structural rigidity of the insulation layer at the corner portion of the storage tank is sequentially arranged, thereby ensuring storage. It is possible to flexibly deal with the level difference problem that occurs at the boundary between the insulation box placed at the corner of the tank and the insulation panel placed in other areas, effectively preventing damage to the membrane of the primary and secondary sealing walls. You can.

In addition, in the insulation system of the LNG storage tank according to the present invention, the lower support structure of the sealing wall is reinforced by a bridge plate connecting adjacent insulation panels, preventing stress from concentrating on a specific part of the membrane, and providing insulation. By making the height difference between panels as continuous as possible, it is possible to prevent stress from being concentrated in discontinuous parts of the membrane due to loads resulting from deformation of the hull.

In addition, the insulation system for the LNG storage tank according to the present invention has the effect of improving productivity in the drying of the LNG storage tank by simplifying the insulation structure around the liquid dome as much as possible.

Figure 1 is a perspective view showing the external appearance of an LNG storage tank according to the present invention.
Figure 2 is a side cross-sectional view schematically showing the corner insulation system of an LNG storage tank according to the present invention.
Figure 3 is a perspective view showing the structure of insulating walls intersecting in an LNG storage tank according to the present invention.
Figure 4 is a diagram to explain the problems of the insulation structure without the bridge structure between insulation panels. (a) shows the stress concentration phenomenon in the membrane according to the load of the cargo, and (b) is due to the deformation of the hull. It shows the stress concentration phenomenon of the membrane according to a load.
Figure 5 is an exploded perspective view showing the laminated structure of the insulation wall and sealing wall in the LNG storage tank according to the present invention.
Figure 6 is a diagram schematically showing the structure of the secondary insulation wall of an LNG storage tank according to the present invention.
Figure 7 is a side cross-sectional view of the secondary insulation wall viewed from direction A of Figure 6.
Figure 8 is a diagram schematically showing the structure of the primary insulation wall of an LNG storage tank according to the present invention.
Figure 9 is a side cross-sectional view of the primary insulation wall viewed from direction B in Figure 8.
Figure 10 is an internal perspective view showing the insulation structure around the liquid dome in the LNG storage tank according to the present invention.
Figure 11 is a side cross-sectional view schematically showing the insulation structure around the liquid dome of the LNG storage tank according to the present invention.
Figure 12 is a view showing an example in which the bridge structure is applied to all corners of the storage tank in the LNG storage tank according to the present invention, (a) shows the structure of the secondary insulation wall, and (b) shows the structure of the primary insulation wall. It represents.

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 the function of primarily sealing or insulating LNG, or the function of secondary sealing or insulating, 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 external appearance of an LNG storage tank according to the present invention, Figure 2 is a side cross-sectional view schematically showing the corner insulation system of the LNG storage tank according to the present invention, and Figure 3 is an LNG storage tank according to the present invention. This is a perspective view showing the structure in which insulating walls are intersected.

First, referring to Figure 1, the LNG storage tank according to the present invention has approximately 135° angles at the upper and lower sides of the storage tank to reduce the sloshing load of the LNG stored therein, especially in the left and right directions. An inclined chamfer may be formed.

Referring to Figure 2, the LNG 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 secondary sealing wall 200, a primary insulation wall 300 consisting of a plurality of primary insulation panels 310 arranged on the secondary sealing wall 200, and a primary insulation wall It can be seen that the insulation system is composed of a double barrier structure, including a primary sealing wall 400 installed on (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 made of plywood or composite material on the upper or lower surfaces of insulation materials such as polyurethane foam (PUF) or reinforced polyurethane foam (R-PUF: Reinforced Polyurethane Foam). It may be provided as a sandwich panel to which a protective plate made of (for example, fiber-reinforced plastic) is bonded.

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 is connected 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 forming the secondary sealing wall 200. ) can be tightly fixed to the top of the.

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

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

In a preferred embodiment of the present invention, the primary sealing wall 400 is made of a corrugation membrane made of stainless steel, and the secondary sealing wall 200 is made of a flat membrane made of Invar LNG. A storage tank is provided.

The primary sealing wall 400 is in direct contact with and seals the LNG, and may include multiple wrinkles formed on the stainless steel membrane toward the inside of the storage tank. The multiple wrinkles absorb shrinkage caused by cryogenic temperatures to reduce stress on the membrane. prevent this concentration.

The secondary sealing wall 200 may be made of a flat Invar membrane. Specifically, the secondary insulation wall 100 is formed by continuously welding a strip-shaped metal plate called an invar strake to a tongue member installed on the upper part of the secondary insulation panel 110. A secondary sealing wall 200 may be installed on the top of.

In the LNG storage tank according to the present invention, a structure made of Invar steel is installed at the transverse corner of the storage tank in order to provide the secondary sealing wall 200 with a flat invar membrane. It can be.

As mentioned above, flat Invar membranes generally have a small heat contraction coefficient, so it is not appropriate to use an insulation panel made of polyurethane foam, that is, a panel type insulation layer, as an insulation wall to support it. not. 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 and high rigidity, that is, a box-shaped insulation layer.

However, the technical problem to be achieved by the present invention is to provide the primary and secondary insulation walls (300, 100) with a panel-type insulation layer made of polyurethane foam, and to form the secondary sealing wall (200) with a metal membrane, especially a flat membrane. The purpose of the present invention is to provide a new type of LNG storage tank insulation system that can be constructed with a flat Invar membrane, and the purpose of the present invention is to provide a transverse connector (a structure made of Invar steel at the corner of the storage tank). This can be achieved by installing a transverse connector, 500).

Specifically, the transverse connector 500 is a grid-shaped structure installed along the edges of the front and rear walls of the storage tank, and one end is welded to an anchoring bar provided on the inner wall of the hull (H) to store It is fixedly installed at the transverse corner of the tank, 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 the present invention, part 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 transverse corner of the storage tank, so that it is relieved. , it is possible to construct the secondary insulation wall 100, which supports the secondary sealing wall 200, which is provided with a flat Invar membrane, from an insulation panel that is less rigid than an insulation box.

In other words, the present invention complements the rigidity of the secondary insulation wall 100 by the transverse connector 500, which is installed at the transverse corner of the storage tank and supports both ends of the secondary sealing wall 200, It is possible to apply a flat Invar membrane of a flat shape as the secondary sealing wall 200.

In addition, the present invention, as part of the configuration for applying the secondary sealing wall 200 as a flat invar membrane, uses high-density glass fiber with a density higher than approximately 130 kg/m ³ as an insulating material constituting the secondary insulation panel 110. Reinforced polyurethane foam (R-PUF) can be used.

Therefore, in the present invention, the secondary insulation wall 100 is composed of an insulation panel made of polyurethane foam, and the secondary sealing wall 200 can be provided with a metal membrane, improving stability, and the secondary sealing wall 200 is provided with a flat invar membrane. When installing the sealing wall 200, the welding line is formed in a straight line, so welding can be automated and productivity is improved.

Additionally, in the present invention, the primary and secondary insulation walls (300, 100) are made of polyurethane foam, thereby improving insulation performance. Compared to the conventional NO 96 type storage tank in which the insulation wall is provided only with an insulation box, the LNG storage tank according to the present invention achieves the same or greater insulation effect while significantly reducing the thickness of the primary and secondary insulation walls. You can.

Meanwhile, in the LNG storage tank according to the present invention, the interior of the transverse connector 500 and between the transverse connector 500 and the hull (H) are insulated with high rigidity to support the transverse connector 500. Box 510 is placed. 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.

Accordingly, the LNG storage tank according to the present invention is composed of insulation panels (310, 110) in which most of the insulation walls (300, 100) are made of polyurethane foam, but an insulation box (510) is formed at the transverse corner portion of the storage tank. It has a mixed structure.

In this way, the structure in which the insulation boxes 510 are mixed in the corner portion can be similarly applied to the longitudinal corner portion of the storage tank. Therefore, the LNG storage tank according to the present invention has a circumferential edge of each wall constituting the storage tank. It has a structure in which a box-type insulation layer is placed along the edge and a panel-type insulation layer is placed toward the inside of the edge.

However, at this time, the rigidity of the insulation box 510 installed at the corner of the storage tank is high, whereas the rigidity of the insulation panels 310 and 110 is low, so there is a difference in the degree of heat shrinkage between the insulation box 510 and the insulation panels 310 and 110. occurs. Therefore, during heat shrinkage by cryogenic LNG, the insulation box 510 and the insulation panels 310, 110 due to the difference in structural integrity of the insulation box 510 and the insulation panels 310, 110 and the thermal load and fluid force of the liquefied gas. ) A height difference occurs due to heat contraction at the boundary between the insulation walls (300, 100), which causes thermal stress to occur in the sealing walls (400, 200) installed on the insulation walls (300, 100), damaging the membranes of the sealing walls (400, 200). There is a risk that it will happen.

In order to prevent this, the insulation system of the LNG storage tank according to the present invention first consists of a primary insulation panel 310 constituting the primary insulation wall 300 and a secondary insulation panel constituting the secondary insulation wall 100. By arranging the (110) to cross each other, damage to the sealing walls (400, 200) due to steps occurring at the boundary between the insulation box (510) and the insulation panels (310, 110) is minimized.

Looking more closely at the intersection arrangement of the primary insulation panel 310 and the secondary insulation panel 110, as shown in FIG. 3, the primary insulation panel 310 is aligned with the secondary insulation panel 110 in the transverse direction. And it may be arranged to be offset from the plurality of secondary insulation panels 110 disposed below so that the longitudinal ends do not all match.

More preferably, the primary insulation panel 310 and the secondary insulation panel 110 are provided with the same width and length, so that the four corners of the primary insulation panel 310 are in the upper center of the secondary insulation panel 110. It can be arranged in such a way that it is fixed to a fixing device provided in, and accordingly, one primary insulation panel 310 can be arranged to span the upper part of the four secondary insulation panels 110 disposed below.

This method of alternating the primary insulation panel 310 and the secondary insulation panel 110 can be applied to the entire wall of the storage tank, and as shown in FIG. 2, it can also be applied to the corners of the storage tank. .

At this time, the insulation box 510 is placed at the level of the primary insulation wall 300 so that the alternating arrangement of the primary insulation panel 310 and the secondary insulation panel 110 can be applied to the corner portion of the storage tank. An insulation box 510' (hereinafter referred to as 'primary corner box') disposed closest to the primary insulation panel 310, and an insulation box 510 disposed at the level of the secondary insulation wall 100. The insulation box 510'' (hereinafter referred to as 'secondary corner box') located closest to the secondary insulation panel 110 is arranged in steps.

The first corner box 510' and the second corner box 510'' are protruding portions of the transverse connector 500 to be connected to the first sealing wall 400 and the second sealing wall 200. It is a configuration placed on the side portion of the transverse connector 500 for support.

The stepped arrangement of the first corner box 510' and the second corner box 510'' is such that the length of the second corner box 510'' along the longitudinal direction of the storage tank is divided into the first corner box 510'. By manufacturing it longer, the secondary corner box 510'' can be configured to protrude more to the outside of the transverse connector 500 than the primary corner box 510'.

Meanwhile, among the plurality of primary insulation panels 310 constituting the primary insulation wall 300, the primary insulation panel 310 disposed at the most corner of the storage tank is located in corner boxes 510' and 510''. The length may be adjusted in consideration of the arrangement with the fields, and, for example, may be formed to be somewhat shorter than other primary insulation panels 310 disposed in areas other than the corners. However, the present invention is not limited to this, and proper arrangement at the corner can be achieved by adjusting the length of the corner boxes 510' and 510'' rather than adjusting the length of the corner-side primary insulation panel 310. It may come true.

In the insulation system of the LNG storage tank according to the present invention, the primary and secondary insulation panels 310 and 110 arranged adjacent to the insulation box 510 are arranged to cross each other, so that the insulation box 510 and the insulation panel 310 , 110), it is possible to prevent damage to the sealing walls 400 and 200 due to a step that occurs at the boundary between them. In the present invention, the alternating arrangement of the primary and secondary insulation panels 310 and 110 can also achieve the effect of increasing insulation performance by extending the heat movement path formed by the gap between the panels.

In addition, the insulation system of the LNG storage tank according to the present invention is to prevent damage to the sealing walls 400 and 200 due to steps occurring at the boundary between the insulation box 510 and the insulation panels 310 and 110. As shown in 2, between the corner boxes (510', 510'') installed at the corner of the storage tank and the insulation panels (310, 110), the corner boxes (510', 510'') and the insulation panel ( Space insulators 320 and 120 having a medium stiffness of 310 and 110 are disposed.

More specifically, between the primary corner box 510' and the primary insulation panel 310, a primary space insulation material ( 320) is placed between the secondary corner box (510'') and the secondary insulation panel (110), and the secondary corner box (510'') and the secondary insulation panel (110) have an average heat shrinkage amount of the secondary corner box (510''). Place the space insulation material 120.

Accordingly, at the corners of the storage tank, corner boxes (510', 510'') with the highest rigidity, space insulation materials (320, 110) with medium rigidity, and insulation panels (310, 110) with the lowest rigidity. These are placed sequentially.

Therefore, in the present invention, as the structural rigidity of the insulation layer at the corner portion of the storage tank is sequentially achieved, the insulation height according to the difference in the degree of thermal contraction increases from the corner box (510', 510'') to the insulation panel (310, 110). Since it can be done gently, the step at the connection between the insulation box 510 and the insulation panels 310 and 110 is minimized, and damage to the primary and secondary sealing walls 400 and 200 can be more effectively prevented. there is.

In addition, the present invention configures the rigidity of the insulation layer constituting the secondary insulation wall 100 to be equal to or greater than the rigidity of the insulation layer constituting the primary insulation wall 300, thereby more efficiently reducing the level difference that occurs at the boundary of the insulation layer. It can be minimized.

As described above, the present invention is characterized in that a panel-type insulation layer made of polyurethane foam is applied to areas beyond the corners of the storage tank.

However, as described above, the amount of heat shrinkage in the insulation panels 310 and 110 is greater under low temperature conditions than the insulation box, and thus greater deformation occurs in the vertical and horizontal directions. Therefore, when heat shrinkage occurs due to the cryogenic temperature of LNG, (a) in Figure 4 ), a large gap may occur between neighboring insulation panels (310, 110), and in this state, when the sealing walls (400, 200) receive the load of cargo (LNG), a specific portion of the membrane There is a problem with stress being concentrated in that area.

In addition, as shown in Figure 4 (b), a vertical step occurs between the neighboring insulation panels 310 and 110 due to the load caused by the deformation of the hull, and stress is concentrated in the discontinuous portion of the membrane caused by the height step. Problems may arise.

In the LNG storage tank according to the present invention, the deformation of the insulation walls 300 and 100 in the vertical direction can be alleviated to some extent by arranging the primary insulation panel 310 and the secondary insulation panel 110 to cross each other. However, this is not a perfect solution, and excessive stress concentration on the membrane may lead to serious problems such as damage to the sealing walls 400 and 200, so a countermeasure is required.

Hereinafter, an insulation system for an LNG storage tank according to the present invention to which a bridge structure is applied to solve the problem pointed out in FIG. 4 will be described with reference to FIGS. 5 to 9.

Figure 5 is an exploded perspective view showing the laminated structure of the insulation wall and sealing wall in the LNG storage tank according to the present invention, Figure 6 is a diagram schematically showing the structure of the secondary insulation wall of the LNG storage tank according to the invention, Figure 7 is a side cross-sectional view of the secondary insulation wall viewed from direction A in Figure 6. Figure 8 is a diagram schematically showing the structure of the primary insulation wall of the LNG storage tank according to the present invention, and Figure 9 is a side cross-sectional view of the primary insulation wall viewed from direction B of Figure 8.

For reference, in FIGS. 6 and 8 , dots are indicated on the first and second bridge plates 311 and 111 to clearly distinguish between components.

Referring to Figures 5 to 9, the LNG storage tank according to the present invention includes a primary bridge plate 311 connecting adjacent primary insulation panels 310, and secondary insulation panels 110 adjacent to each other. ) may further include a secondary bridge plate 111 connecting the

The first and second bridge plates 311 and 111 may be made of the same material as the upper protective plates of the insulation panels 310 and 110. That is, the first and second bridge plates 311 and 111 may be made of composite materials such as plywood or fiber-reinforced plastic.

First, referring to FIGS. 5 to 7, looking at the bridge structure applied to the secondary insulation wall 100, the secondary bridge plate 111 is arranged to span between neighboring secondary insulation panels 110. You can see that it is a structure.

A step portion on which the secondary bridge plate 111 is seated is formed along the upper edge of the secondary insulation panel 110, and 2 is disposed in the space formed by the step portion of the secondary insulation panel 110 adjacent to each other. The upper surface of the secondary bridge plate 111 may be flush with the upper protective plate of the secondary insulation panel 110.

The secondary bridge plate 111 may be provided as a plurality of unit plates and continuously arranged along the longitudinal and transverse directions of the storage tank. The secondary bridge plate 111 arranged in the longitudinal direction connects the longitudinal edges of the secondary insulation panel 110, and the secondary bridge plate 111 arranged in the transverse direction connects the edges of the secondary insulation panel 110 to each other. Connect the widthwise edges to each other.

In addition, as shown in FIG. 6, the invar strakes constituting the secondary sealing wall 200 are arranged so that their width-direction edges coincide with the tongue line formed on the upper part of the secondary insulation panel 110. The secondary bridge plate 111 arranged along the longitudinal direction of the storage tank supports the middle part of the Invar strake.

Next, referring to FIGS. 5, 8, and 9, it can be seen that the bridge structure applied to the primary insulation wall 300 is provided in a similar form to the bridge structure applied to the secondary insulation wall 100 described above. there is.

That is, the primary bridge plate 311 is disposed at a step formed along the upper edge of the primary insulation panel 310 to connect the upper surfaces of neighboring primary insulation panels 310, and the primary bridge plate (311) In addition, as described above, it is provided as a unit plate and can be continuously arranged along the longitudinal and transverse directions of the storage tank.

In addition, as shown in FIG. 8, the edge of the unit membrane constituting the primary sealing wall 400 is welded to an anchor strip installed on the top of the primary insulation panel 310, so the primary bridge Plate 311 supports the middle portion of the unit membrane.

The first and second bridge plates 311 and 111 may be fixed to the step portions formed at the upper edges of the insulation panels 310 and 110 using fastening members such as screws or rivets.

At this time, the primary insulation panel 310 is exposed to a lower temperature than the secondary insulation panel 110, and since the lower parts of the panels are not joined by bonding, significant heat shrinkage occurs. Therefore, it is desirable that both ends of the primary bridge plate 320 be fixed to the stepped portions of both primary insulation panels 310 in order to control the thermal contraction of the panel.

On the other hand, in the case of the secondary insulation panel 110, heat shrinkage occurs relatively less than that of the primary insulation panel 310, so it may be fixed to at least one or more of both ends of the secondary bridge plate 120.

This bridge structure is applied not only between the insulation panels 310 and 110, but also between the insulation boxes 510, more precisely, the corner boxes 510' and 510'' and the insulation panels 310, 110) It can also be applied to the liver.

Reference numeral 112 is a flat joint made of glass wool that is inserted into the space between the secondary insulation panels 110 and performs an insulation function. Although not shown in the drawing, the flat joint may also be inserted into the space between the primary insulation panels 310.

In the insulation system of the LNG storage tank according to the present invention, the lower support structure of the sealing walls (400, 200) is reinforced by bridge plates (311, 111) connecting adjacent insulation panels (310, 110), thereby forming a membrane. It prevents stress from concentrating on a specific part, and the height difference between the insulation panels 310 and 110 is made as continuous as possible to prevent stress from concentrating on discontinuous parts of the membrane due to the load resulting from deformation of the hull. It has a preventive effect.

Meanwhile, the LNG storage tank is equipped with a liquid dome as a passage for loading and unloading. The liquid dome is located at the top of the LNG storage tank and forms part of the LNG storage tank as a passage for loading and unloading LNG.

Figure 10 is an internal perspective view showing the insulation structure around the liquid dome in the LNG storage tank according to the present invention, and Figure 11 is a side cross-sectional view schematically showing the insulation structure around the liquid dome of the LNG storage tank according to the present invention. For reference, Figure 10 shows the inside of the storage tank facing upward for convenience of explanation.

Referring to Figure 10, in the LNG storage tank according to the present invention, a liquid dome box forming a liquid dome is disposed close to the rear wall of the storage tank. In other words, the liquid dome box is placed on the rear side of the LNG storage tank toward the stern.

As described above, the present invention can apply the concept of sequentially arranging the structural rigidity of the insulation layer at the corner of the storage tank to the periphery of the liquid dome.

Referring to FIG. 11, the present invention arranges highly rigid primary and secondary insulation boxes 330 and 130 around the liquid dome 600, and provides primary and secondary space insulation ( 320, 120), and the first and second insulation panels 310, 110 may be arranged sequentially.

This arrangement structure can be applied without problem between the liquid dome 600 and the front wall of the storage tank (right part of the liquid dome in Figure 11) and between the liquid dome 600 and the side wall of the storage tank (not shown). there is.

However, in the present invention, the liquid dome 600 is disposed close to the rear wall of the storage tank, so there is sufficient space for an insulation panel to be placed between the liquid dome 600 and the rear wall of the storage tank (left portion of the liquid dome in FIG. 11). Space is not secured.

Therefore, the LNG storage tank according to the present invention is provided to support the transverse connector 500 at the corner of the storage tank without arranging the insulation panels 310 and 110 between the liquid dome 600 and the rear wall of the storage tank. Only the insulation box 510 and the insulation boxes 330 and 130 installed around the liquid dome 600 are placed.

In addition, since the insulation panels 310 and 110 are not placed in the space (between the liquid dome and the rear wall of the storage tank), the level difference problem that occurs at the boundary between the box-type insulation layer and the panel-type insulation layer does not occur, so the boundary area There is no practical benefit in arranging the space insulators 320 and 120.

Therefore, in the present invention, the primary and secondary insulation walls (300, 100) formed between the liquid dome (600) and the rear wall of the storage tank include not only the insulation panels (310, 110) but also the space insulation materials (320, 120). An insulation system for an LNG storage tank is provided, which is removed and consists of only a box-shaped insulation layer.

The insulation box 510 provided to support the transverse connector 500 and the primary and secondary insulation boxes 330 and 130 disposed around the liquid dome 600 may be slightly different in size. However, since the plywood box can be provided with the same structure in which the inside is filled with an insulating material such as perlite powder or glass wool, in FIG. 11, the primary corner box 510' provided to support the transverse connector 500 is shown. and the member numbers of the secondary corner box (510'') were unified with the primary insulation box (330) and secondary insulation box (130), respectively.

The secondary insulation wall 100 formed between the liquid dome 600 and the rear wall of the storage tank is composed of a single secondary insulation box 130 as shown in (a) of FIG. 11, or As shown in (b) of 11, it may be composed of a plurality of secondary insulation boxes 130.

In addition, the primary insulation wall 300 formed between the liquid dome 600 and the rear wall of the storage tank may be composed of a plurality of primary insulation boxes 330, where the primary insulation box 330 is 2 It is arranged to intersect with the car insulation box (130). Cross arrangement in this area means that the boundary between neighboring primary insulation boxes 330 does not match the end of the secondary insulation box 130 or the boundary between neighboring secondary insulation boxes 130 and is arranged misaligned. means that

Figures 11 (a) and (b) are just one example of various embodiments of the present invention, and the primary and secondary insulation boxes 330 and 130 may be provided in larger numbers than those shown in Figure 11. It might be possible. However, even according to other embodiments, it is preferable that the primary insulation box 330 and the secondary insulation box 130 are arranged to cross each other.

Meanwhile, if the bridge structure of the present invention described above is applied between the insulating boxes 330 and 130, a structure as shown in FIG. 12 will be obtained. The embodiment shown in FIG. 12 has a structure in which a secondary bridge plate and a primary bridge plate are arranged along the transverse direction of the storage tank at the corner portion formed between the liquid dome and the rear wall of the storage tank.

However, the thermal shrinkage of the insulating boxes 330 and 130 is not large, so the vertical step or the gap between the insulating boxes 330 and 130 in the horizontal direction can be appropriately controlled, so the insulating boxes 330 and 130 as in the embodiment shown in FIG. 12. ), there is not much benefit from applying the bridge structure to the liver.

Therefore, in the LNG storage tank according to the present invention, as shown in FIG. 11, the primary and secondary insulation walls 300 and 100 formed between the liquid dome 600 and the rear wall of the storage tank are box-shaped insulation layers. As a more preferable embodiment, it is configured to consist only of a combination of boxes 330 and 130, and no bridge structure is applied to the corresponding area.

The insulation system for the LNG storage tank according to the present invention has the effect of improving productivity in the drying of the LNG storage tank by simplifying the insulation structure around the liquid dome 600 as much as possible.

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
111: secondary bridge plate
120: secondary space insulation 130: secondary insulation box
200: secondary sealing wall
300: Primary insulation wall 310: Primary insulation panel
311: primary bridge plate
320: Primary space insulation 330: Primary insulation box
400: Primary sealing wall
500: Transverse connector 510: Insulation box
510': 1st corner box 510'': 2nd corner box
600: Liquid Dome

Claims (6)

In the insulation system of an LNG storage tank including a liquid dome formed on the upper part of the rear side in the stern direction,
A sealing wall made of a metal membrane to seal the LNG stored in the LNG storage tank; And an insulating wall installed outside the sealing wall to insulate the LNG,
The insulation wall includes an insulation box filled with insulation material inside a plywood box; And an insulation panel in the form of a protective plate made of plywood or fiber-reinforced plastic attached to at least one of the upper and lower surfaces of the polyurethane foam as a component,
The insulation box is arranged around the edge of the inner wall of the LNG storage tank and around the liquid dome, and the insulation panel is arranged in areas other than the area where the insulation box is arranged on the inner wall of the LNG storage tank,
The insulation wall formed between the liquid dome and the rear wall of the LNG storage tank is formed only by a combination of the insulation boxes without the arrangement of the insulation panels,
The insulation panels disposed adjacent to each other on the insulation wall have a bridge structure in which their upper surfaces are connected to each other by a bridge plate, and the bridge structure is applied between the insulation boxes disposed between the liquid dome and the rear wall of the LNG storage tank. Characterized in that does not apply,
Insulation system of LNG storage tank. In claim 1,
The bridge structure is characterized in that it is also applied between the insulation box and the insulation panel arranged adjacent to each other.
Insulation system of LNG storage tank. In claim 2,
The bridge structure is characterized in that adjacent insulation panels or adjacent insulation panels and insulation boxes are connected by a bridge plate,
Insulation system of LNG storage tank. In claim 3,
The bridge plate is seated across a step formed around the upper edge of one of the insulation panels and a step formed around the upper edge of the insulation panel or insulation box adjacent to the one of the insulation panels, Characterized in that the upper surface of any of the insulation panels and the neighboring insulation panel or insulation box is connected,
Insulation system of LNG storage tank. In claim 2,
The sealing wall includes: a primary sealing wall that primarily seals the LNG; And a secondary sealing wall that secondarily seals the LNG,
The insulation wall includes: a primary insulation wall disposed between the primary sealing wall and the secondary sealing wall; And a secondary insulation wall disposed between the secondary sealing wall and the inner wall of the hull,
The secondary insulation wall formed in the space between the liquid dome and the rear wall of the LNG storage tank is composed of a single or a plurality of secondary insulation boxes arranged along the longitudinal direction of the LNG storage tank,
The primary insulation wall formed in the space between the liquid dome and the rear wall of the LNG storage tank is composed of a plurality of primary insulation boxes arranged along the longitudinal direction of the LNG storage tank,
Characterized in that the primary insulation box and the secondary insulation box are arranged alternately,
Insulation system of LNG storage tank. In claim 5,
Characterized in that the boundary between the neighboring primary insulation boxes is arranged to be offset from the end of the secondary insulation box,
Insulation system of LNG storage tank.

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