KR20130110739A

KR20130110739A - Insulation structure for lng storage tank

Info

Publication number: KR20130110739A
Application number: KR1020120032936A
Authority: KR
Inventors: 최고은; 현재균; 박철웅
Original assignee: 대우조선해양 주식회사
Priority date: 2012-03-30
Filing date: 2012-03-30
Publication date: 2013-10-10

Abstract

PURPOSE: An insulation structure for an LNG storage tank is provided to improve insulation performance by forming an enough space inside of an insulation box and improve the stability of a ship by efficiently circulating inactive gas. CONSTITUTION: An insulation structure for an LNG storage tank comprises an insulation box (100) and multiple entasis columns (200). The insulation box has a sealed inner space and insulates LNG. Both ends of the entasis columns are coupled to the sealed inner space of the insulation box. Both ends of the entasis columns have a shorter diameter than the center portion.

Description

Insulation Structure For LNG Storage Tank

The present invention relates to a heat insulating structure for an LNG storage tank, and more particularly to a heat insulating structure for an LNG storage tank to which the internal material of the drainage column type is applied in a GT NO96 type heat insulating box.

Natural gas is a fossil fuel containing methane as a main component and a small amount of ethane, propane, and the like, and has recently been regarded as a low-pollution energy source in various technical fields.

Natural gas is transported in a gaseous state through land or sea gas pipelines, or is transported to a remote location where it is stored in an LNG carrier in the form of liquefied natural gas (LNG). Liquefied natural gas is obtained by cooling natural gas at cryogenic temperatures (approximately -163 ° C), and its volume is reduced to approximately 1/600 of that of natural gas, making it well suited for long-distance transport through the sea.

The liquefied natural gas carrier is equipped with a cargo (also referred to as a storage tank) capable of storing and storing liquefied natural gas that has been liquefied by cooling the natural gas. Since the boiling point of liquefied natural gas is about -163 ℃ at atmospheric pressure, the cargo hold of liquefied natural gas is made of materials that can withstand ultra low temperatures such as aluminum steel, stainless steel, and 35% nickel steel to safely store and store liquefied natural gas. It is designed to be resistant to thermal stress and heat shrinkage and to prevent thermal intrusion.

LNG RV (Regasification Vessel), which transports LNG carrier and LNG for loading and unloading LNG to land demand by loading LNG and landing in natural gas, Floating marine structures such as LNG FPSO (Floating, Production, Storage and Offloading) and LNG FSRU (FSRU) also include storage tanks installed in LNG carriers or LNG RVs.

LNG FPSO is a floating marine structure that is used to liquefy natural gas produced directly from the sea and store it in a storage tank and, if necessary, to transfer the LNG stored in this storage tank to an LNG carrier. In addition, the LNG FSRU is a floating type of floating structure that stores LNG unloaded from LNG carriers in offshore sea, stores it in a storage tank, vaporizes LNG if necessary, and supplies the LNG to the customer.

In this way, a storage tank for storing LNG in a cryogenic condition is installed in a marine structure such as an LNG carrier, LNG RV, LNG FPSO, and LNG FSRU that transports or stores a liquid cargo such as LNG.

This storage tank can be classified as an independent tank type or a membrane type depending on whether the load of the cargo directly acts on the heat insulating material. As shown in Table 1 below, membrane type storage tanks are generally divided into GT NO 96 type and TGZ Mark III type, and independent tank type storage tanks are divided into MOSS type and IHI-SPB type.

The GT and TGZ tank structures described above are described in U.S. Patent Nos. 6,035,795, 6,378,722, 5,586,513, and U.S. Patent Publication Nos. 2003-0000949 and the like, and Korean Patent Publication Nos. 10-2000-0011347 and 10-2000- 0011346 and the like. In addition, the structure of the independent tank type storage tank is described in Korean Patent Nos. 10-15063 and 10-305513.

The GT NO 96 type storage tank includes a primary sealing wall and a secondary sealing wall made of Invar steel (36% Ni) having a thickness of 0.5 to 1.5 mm, a plywood box and a perlite. The primary heat insulation wall and the secondary heat insulation wall which consist of) are alternately laminated on the inner surface of a ship body.

In the case of the GT NO 96 type, the primary sealing wall and the secondary sealing wall have almost the same degree of liquid tightness and strength, so that when the primary sealing wall leaks, the secondary sealing wall alone can safely support the cargo. . In addition, GTNO 96-type sealing wall has a straight membrane, so welding is easier than TGZ Mark III-type corrugated membrane, and the automation rate is high, but the overall welding length is longer than TGZ Mark III type. In the case of GT NO 96, a double couple is used to support an insulation box (ie, an insulation wall). French Patent Nos. 2146612, 2629897, 2683786 and the like disclose a configuration and fixing method of a conventional GT NO 96 type insulation box.

Figure 1 is a perspective view of a thermal insulation box used in the GT NO 96 storage tank according to the prior art installed inside the hull (S). In FIG. 1, the conventional heat insulation box is shown with the heat insulation material removed to show its internal structure. The conventional GT NO 96 type heat insulating box constituting the primary heat insulating wall and the secondary heat insulating wall 20 in FIG. 1 has a substantially rectangular parallelepiped shape.

A plurality of horizontal members 11 extending in the horizontal direction for reinforcement are installed in the conventional heat insulation box 10, and a fixing member protruding from the heat insulation box to fix the heat insulation box to the inner surface of the hull. do. In addition, a circular circulation hole is formed in the front and rear wall members and the horizontal member of the insulation box so as to circulate the inert gas (for example, nitrogen) in preparation for the leakage of LNG.

However, in the conventional GT NO 96 type insulation box, the horizontal member is connected by stapling, which requires considerable attention in the manufacturing process, resulting in inefficient work efficiency. In addition, the quality of the stapling work for bonding with the top plate was difficult to identify unless the insulation box was disassembled.

In addition, the reinforcing horizontal member made of an expensive material plywood is also uneconomical because it is densely arranged inside the insulating box to meet the strength required for the insulating box, which reduces the proportion of pearlite, which is relatively the main insulating material. It may result in poor insulation performance. The increase in weight due to the tightly arranged plywood can make the work difficult during installation work, cause safety accidents and increase transportation costs.

In addition, since the strength of the center portion where the circulation hole is formed for the circulation of inert gas in the insulation box is relatively weak compared to the rest, it is vulnerable to buckling due to external load, and the gas circulation is smooth due to the limited size of the circulation hole. It has also been pointed out as a problem.

The present invention is to solve the conventional problems as described above, by replacing the plywood formed with a circulation hole by applying the inner material of the drainage pillar shape for an economical LNG storage tank having a light but excellent buckling strength and insulation performance To provide an insulation structure.

According to an aspect of the present invention, in the insulating structure of the cargo hold in which the liquefied natural gas is stored, the insulating box to form a sealed space therein and insulate the liquefied natural gas; And a plurality of drainage pillars having both ends coupled to the closed space of the insulation box.

The plurality of drainage pillars may be characterized in that the cylinder in the form of a drainage that decreases the diameter of the cross-section toward both ends.

The drainage pillar may be fixed by guide plates spaced apart from each other on the upper and lower sides of the insulation box.

It may include a heat insulating material filled in the inner space of the heat insulation box.

The insulation may be selected from the group comprising airgel, polyurethane foam and polystyrene.

The insulation box is a primary insulation box that primarily insulates the liquefied natural gas; And a secondary insulation box disposed between the primary insulation box and the inner wall of the hull to insulate the liquefied natural gas secondaryly.

According to another aspect of the present invention, an LNG storage tank including the above-described insulation structure for the LNG storage tank may be provided.

According to another aspect of the present invention, a ship or offshore structure provided with an LNG storage tank including an insulating box provided with a plurality of drainage columns therein and insulates the liquefied natural gas.

According to another aspect of the present invention, in the heat insulation structure of the cargo hold in which the liquefied natural gas is stored, a sealed space is formed therein and is provided with an insulating box for insulating the liquefied natural gas, the closed of the thermal insulation box A plurality of triangular pillars provided in the space may be provided with an insulating structure for the LNG storage tank, characterized in that both ends are fixed by the guide plate spaced apart on the upper and lower sides of the insulating box.

The insulation structure for LNG storage tank of the present invention can provide a light and economical insulation box by applying a drainage pillar-shaped inner material in place of the relatively heavy and expensive plywood, and also by forming a sufficient space inside the insulation box Excellent insulation performance can be achieved by the main insulation material, and the safety of ship can be improved by smooth circulation of inert gas.

Figure 1 schematically shows the internal structure of the cargo box of the vessel equipped with a conventional GT NO 96 type thermal insulation box and the insulation box of the insulation material is removed.
Figure 2 is a side cross-sectional view of the insulation box for LNG storage tank applied drainage column according to an embodiment of the present invention.
Figure 3 is a cross-sectional view from above of the shape of the column-shaped drainage column according to an embodiment of the present invention disposed on the guide plate.
Figure 4 is a cross-sectional view of the triangular pillar according to an embodiment of the present invention viewed from the top of the heat insulation box disposed on the guide plate.

In order to fully understand the present invention, operational advantages of the present invention, and objects achieved by the practice of the present invention, reference should be made to the accompanying drawings and the accompanying drawings which illustrate preferred embodiments of the present invention.

Hereinafter, the present invention will be described in detail with reference to the preferred embodiments of the present invention with reference to the accompanying drawings.

2 is a side cross-sectional view of the insulation box 100 for an LNG storage tank to which the drainage column 200 is applied according to an embodiment of the present invention.

As shown in Figure 2, the insulating structure for the LNG storage tank according to an embodiment of the present invention, as an insulating structure of the cargo hold in which the liquefied natural gas is stored to form a sealed space therein and to insulate the liquefied natural gas The insulation box 100 may include a plurality of drainage pillars 200 having both ends coupled to a closed space of the insulation box 100.

The plurality of drainage pillars 200 may be cylinders of a drainage shape in which the diameter of the cross section decreases toward both ends.

In the present embodiment, the columnar drainage pillar 200a having a thick central portion and decreasing the diameter of the cross section toward both ends is applied to a closed space inside the insulation box 100.

This method of drainage is a technique that has been widely used in architecture. It is a technique for correcting structural stability and optical illusion and is the same as the entasis of Western architecture.

Representatively, we can find the pillar of drainage in Buseoksa martial arts faucet, our cultural property.

This drainage method has an effect of improving the resistance to the vertical load, the building to which the drainage column is applied, the structural stability is improved, the present invention focused on this point.

By applying the drainage column 200 to replace the horizontal member made of plywood in the inner space of the insulation box 100 for the LNG storage tank, it is possible to provide an insulation structure excellent in resistance to vertical load.

Compared to plywood, the drainage column 200 may provide more space in the insulation box 100 to fill more main insulation, thereby improving the insulation effect.

The inner material in the form of the drainage pillar 200 may change the thickness, the number of installation, the material, etc. in consideration of the design conditions of the cargo hold, that is, the storage tank. By using plastics such as polycarbonate rather than wood type, it will be possible to manufacture the interior material of the drainage pillar 200 which is excellent in processability and can satisfy the desired strength condition.

The interior of the drainage pillar 200 is lighter than the plywood, easier to work with the heavy plywood, and can reduce the transportation cost by reducing the weight of the insulation box 100.

The drainage column 200 may be fixed by the guide plate 300 spaced apart from the upper and lower sides of the heat insulation box 100.

The guide plate 300 is attached to both upper and lower sides of the heat insulation box 100, and fixes the drainage pillar 200 to a groove formed in the guide plate 300 in a suitable manner such as stapling, bonding, and fitting.

The spacing of the guide plate 300 is determined in consideration of the spacing of the drainage pillars 200.

The guide plate 300 not only provides a function of fixing the internal shape of the drainage pillar 200, but also provides excellent fixing force and workability in a wide stapling area when fixing the stapling method.

It may include a heat insulating material filled in the inner space of the heat insulation box 100.

Insulation may be selected from the group comprising airgel, polyurethane foam and polystyrene. These may be used singly or in combination.

Such a heat insulating material may be stacked in an inner space of the sealed heat insulating box 100 in a matrix form of a predetermined thickness, or may be installed in a form of filling into a suitable size and the like.

The insulation box 100 may include a primary insulation box that primarily insulates the liquefied natural gas, and a secondary insulation box that is disposed between the primary insulation box and the inner wall of the hull to insulate the liquefied natural gas secondaryly. have.

In the GT NO 96 type insulation system, the primary insulation box functions as the primary insulation wall and the secondary insulation box acts as the secondary insulation wall, between the primary insulation box and the hull inner wall and between the primary and secondary insulation boxes. Sealing walls can be installed.

According to another embodiment of the present invention, an LNG storage tank including the above-described insulation structure for the LNG storage tank may be provided.

According to another embodiment of the present invention, a ship or offshore structure provided with an LNG storage tank including an insulating box 100 having a plurality of drainage columns 200 therein and insulating the liquefied natural gas may be provided. .

As shown in Figure 4, according to another embodiment of the present invention, as a heat insulation structure of the cargo hold in which the liquefied natural gas is stored, a sealed space is formed inside and is provided with an insulating box 100 for insulating the liquefied natural gas For the LNG storage tank, a plurality of triangular pillars 200b provided in the sealed space of the heat insulation box 100 are fixed at both ends by guide plates 300 spaced apart from each other on the upper and lower sides of the heat insulation box. An insulating structure may be provided.

In the case of the same cross-sectional area of the same material, since the triangular shape is a relatively large cross-sectional secondary moment and the cross-sectional coefficient, if the triangular prism (200b) is applied, it is possible to manufacture a thermal insulation box 100 excellent in buckling resistance.

In addition, compared to the plywood triangular pillar (200b) also provides a lot of space inside the insulation box 100 to fill more main insulation material, thereby improving the thermal insulation effect.

As described above, the present embodiment is an LNG storage tank in which a plurality of columnar pillars 200a or triangular pillars 200b of a cylindrical shape are fixed to the grooves of the guide plates 300 coupled to the upper and lower sides of the insulation box 100. By providing a heat insulating structure for the structure, it is possible to provide a light and economical heat insulation box that adopts a pillar-shaped inner material in place of a relatively heavy and expensive plywood, and also to provide sufficient space inside the heat insulation box, thereby providing excellent heat insulation by the main insulation material. Performance can be achieved and the safety of the ship can be improved by smooth circulation of inert gas.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Accordingly, such modifications or variations are intended to fall within the scope of the appended claims.

S: hull
100: insulation box
200: shedding pillar
200a: columnar pillars
200b: Triangular prism
300: guide plate

Claims

In the insulation structure of the cargo hold in which liquefied natural gas is stored,
An insulation box having a sealed space therein and insulating the liquefied natural gas; And
Insulation structure for an LNG storage tank, characterized in that it comprises a plurality of drainage column coupled to both ends in the sealed space of the heat insulation box.

The method of claim 1,
The plurality of drainage pillar is a heat insulation structure for LNG storage tank, characterized in that the cylinder of the shape of the flow of the cross section is reduced toward both ends.

The method of claim 1,
The drainage pillar is an insulating structure for LNG storage tank, characterized in that fixed by the guide plate spaced apart from the upper and lower sides of the insulating box.

The method of claim 1,
Insulation structure for an LNG storage tank including a heat insulating material filled in the inner space of the heat insulation box.

6. The method of claim 5,
The insulation is an insulation structure for LNG storage tanks, characterized in that selected from the group consisting of airgel, polyurethane foam and polystyrene.

According to claim 1, wherein the insulating box
A primary insulation box for insulating the liquefied natural gas primarily; And
The insulation structure for the LNG storage tank, characterized in that it comprises a secondary insulation box disposed between the primary insulation box and the inner wall of the hull secondary insulation of the liquefied natural gas.

An LNG storage tank comprising the insulation structure for LNG storage tank according to any one of claims 1 to 7.

A ship or offshore structure provided with an LNG storage tank that insulates liquefied natural gas and includes an insulation box provided with a plurality of drainage columns therein.

In the insulation structure of the cargo hold in which liquefied natural gas is stored,
An enclosed space is formed therein, and an insulation box is provided to insulate the liquefied natural gas. Insulating structure for LNG storage tank, characterized in that both ends are fixed by.