KR101985211B1 - Liquefied gas storage tank and Ship or offshore structure including the same - Google Patents

Abstract

A liquefied gas storage tank and a ship or an offshore structure comprising the same are disclosed. The liquefied gas storage tank according to an embodiment of the present invention stores liquefied gas in an internal space, and includes a first primary barrier having a corrugated shape defining the internal space, A first wrinkle located below the free surface of the liquefied gas stored in the inner space and a second wrinkle located above the free surface, wherein the first wrinkle has a lower withstand pressure performance than the second wrinkle, Is high.

Description

TECHNICAL FIELD [0001] The present invention relates to a liquefied gas storage tank and a ship or an offshore structure including the liquefied gas storage tank,

The present invention relates to a liquefied gas storage tank and a ship or an offshore structure comprising the same.

Liquefied natural gas storage tanks are used for storing or transporting extremely low temperature Liquefied Natural Gas (LNG) at about -163 ° C. It is equipped with two barriers (primary barrier and secondary barrier) to seal liquefied natural gas do.

The liquefied natural gas storage tank has a plywood structure in a heat insulating member made of polyurethane foam having a low thermal conductivity between a primary barrier and a secondary barrier, a secondary barrier and an inner hull, A heat insulating layer is formed by using a heat insulating board having a heat insulating member protecting plate having a high compressive strength.

At this time, since the primary barrier of the liquefied natural gas storage tank is in direct contact with the liquefied natural gas, high airtightness is required.

The liquefied natural gas storage tank is welded to a plurality of membranes made of stainless steel to form a primary barrier. When these primary barriers come into contact with cryogenic liquefied natural gas, heat shrinkage occurs. When the heat shrinkage occurs, And can be damaged.

Because of this problem, the primary barrier has a corrugation to have low in-plane stiffness. The wrinkle part deforms a certain amount when heat shrinkage occurs, thereby reducing the thermal stress at the welded part.

On the other hand, when the liquefied natural gas storage tank storing the liquefied natural gas is transported by a transportation means such as a ship, the surface of the liquefied natural gas stored by the movement such as rolling, pitching, It may occur.

Such sloshing is called sloshing, and this sloshing applies a large compressive force to the primary barrier. If the compressive force due to sloshing exceeds the yield strength of the primary barrier, permanent deformation may occur in the wrinkles most vulnerable to deformation and the safety of the primary barrier may deteriorate.

Accordingly, the primary barrier should have a high pressure resistance performance corresponding to the compressive force by sloshing while maintaining low surface rigidity in response to heat shrinkage.

An embodiment of the present invention is to provide a liquefied gas storage tank having high flexibility in heat shrinking and a ship or an offshore structure including the same.

According to an aspect of the present invention, there is provided a liquefied gas storage tank for storing a liquefied gas in an internal space, the liquefied gas storage tank including a first primary barrier having a corrugated shape defining the internal space, A first wrinkle located below the free surface of the liquefied gas stored in the inner space and a second wrinkle located above the free surface, wherein the first wrinkle has a lower withstand pressure performance than the second wrinkle, A liquefied gas storage tank may be provided.

Wherein the first wrinkles have a structure having two or more peak portions convex toward the inner space and the second wrinkles have a structure having one peak portion convex toward the inner space, and the length of the outline of the first wrinkles is May be longer than the length of the outline of the second pleats.

The first corrugation may have a structure having three peak portions convex toward the inner space.

The first wrinkles have symmetrical shapes on both sides with respect to the first wrinkle center line, and the second wrinkles may have symmetrical shapes on both sides with respect to the second wrinkle center line.

The first wrinkles may have a structure in which the middle peak portion of the three peak portions is more convex toward the inner space than the rest.

According to another aspect of the present invention, a vessel or an offshore structure including the liquefied gas storage tank may be provided.

According to the embodiment of the present invention, the first fold is formed on the first barrier, and the first fold located below the free surface of the liquefied gas stored in the inner space has lower pressure resistance performance than the second fold located on the free surface, It is possible to have high flexibility in heat shrinkage as compared with the conventional liquefied gas storage tanks.

1 is a cross-sectional view of a liquefied gas storage tank according to an embodiment of the present invention,
Fig. 2 is an enlarged view of a portion A in Fig. 1,
Fig. 3 is an enlarged view of a portion B in Fig. 1,
FIG. 4 is an enlarged view of the first folds shown in FIG. 2,
5 is an enlarged view of the second fold shown in Fig.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Referring to the accompanying drawings, the same or corresponding components are denoted by the same reference numerals, do.

FIG. 1 is a cross-sectional view of a liquefied gas storage tank according to an embodiment of the present invention, FIG. 2 is an enlarged view of a portion A of FIG. 1, and FIG. 3 is an enlarged view of a portion B of FIG. 1 to 3, + X denotes the front of the liquefied gas storage tank or the front of the hull where the liquefied gas storage tank is formed, + Y denotes the left side of the liquefied gas storage tank, As shown in FIG.

1 to 3, the liquefied gas storage tank 100 according to the present embodiment stores liquefied gas therein. For example, the liquefied gas may be any of liquefied natural gas, liquefied nitrogen, liquefied hydrogen, liquefied propane, liquefied ethylene, liquefied ammonia. In addition, the liquefied gas may comprise any gas generally stored in a liquid state.

The liquefied gas storage tank 100 according to the present embodiment may be formed in the hull 10 of a ship or an offshore structure.

2 and 3, the liquefied gas storage tank 100 includes a primary barrier 110, a secondary barrier 120, a primary barrier 110 and a secondary barrier 120 interposed between the primary barrier 110 and the secondary barrier 120. [ And a secondary insulation layer 140 interposed between the secondary insulation 120 and the inner wall 11 of the hull 10.

The primary barriers 110 are arranged in direct contact with the liquefied gas and spaced from the inner wall 11 constituting the hull 10 toward the liquefied gas.

The primary barrier 110 may be composed of a plurality of membranes (not shown), and the membranes may be made of stainless steel. These membranes can be bonded by welding at the interface.

Wrinkles 200 are formed in the primary barrier 110.

The wrinkles 200 include a first wrinkle 210 as shown in FIG. 2 and a second wrinkle 220 as shown in FIG.

The first corrugation 210 is located below the free surface of the liquefied gas stored in the inner space 101 as shown in FIG.

The second corrugations 220 are located on the free surface of the liquefied gas stored in the interior space 101 as in Fig.

The first wrinkle 210 may include wrinkles extending in the vertical direction, not shown, in addition to the wrinkles extending in the horizontal direction as shown in Fig.

The second corrugations 220 may include corrugations extending in the vertical direction, not shown, in addition to the corrugations extending in the horizontal direction as shown in FIG.

The first wrinkle 210 has a lower withstand pressure performance than the second wrinkle 220 and has a high flexibility against heat shrinkage. This will be described later.

The secondary barrier 120 may be interposed between the primary barrier 110 and the inner wall 11 of the hull 10. The secondary barrier 120 may be composed of a plurality of membranes, and the membranes may be made of any one of stainless steel, aluminum, brass, and zinc.

The primary insulating layer 130 is interposed between the primary barrier 110 and the secondary barrier 120.

The primary heat insulating layer 130 may include a plurality of primary unit heat insulating blocks 131 and a primary heat insulating filler 133.

The plurality of primary unit heat insulating blocks 131 may be disposed adjacent to each other. The primary unit heat insulating block 131 may be formed of any one of a polyurethane foam, a micro-celluloid foam, a nano-celluloid foam, and a sandwich foam.

The primary heat insulating block 131 may be filled with the primary heat insulating filler 133. The primary adiabatic filler 133 may be composed of various materials capable of enhancing the heat insulating performance of the primary unit adiabatic blocks 131 such as a flexible adiabatic foam, a glass wool, and a putty.

An impact absorbing layer 135 may be interposed between the primary barrier 110 and the primary insulating layer 130. The impact absorbing layer 135 may be composed of various materials having a stiffness lower than that of the primary barrier 110, for example, a fiber-reinforced composite sheet or mat, a polymer resin, rubber, or the like.

The impact absorbing layer 135 may be bonded to the back surface of the primary barrier 110 by an adhesive such as an epoxy resin or by hot pressing.

A flywheel (not shown) may be provided between the impact absorbing layer 135 and the primary heat insulating layer 130 to reinforce the rigidity.

The secondary insulation layer 140 may be interposed between the secondary barrier 120 and the inner wall 11 of the hull 10.

The secondary insulation layer 140 may include a plurality of secondary insulation blocks 141 and a secondary insulation 143. The plurality of secondary unit heat insulating blocks 141 may be disposed adjacent to each other. The secondary unit heat insulating block 141 may be composed of polyurethane foam, sandwich foam, microcelluloid foam, nanocelluloid foam, and the like.

And between the adjacent secondary unit insulation blocks 141, the secondary insulation 143 may be filled. The secondary adiabatic filling material 143 may be composed of various materials capable of improving the heat insulating performance of the secondary unit insulating blocks 141 such as a flexible insulating foam, a glass wool, and a putty.

The primary unit heat insulating block 131 and the secondary unit heat insulating block 141 may be arranged so as to be offset from each other in order to prevent leakage of electrolytic gas that has been charged.

The secondary insulation layer 140 may be fixed to the inner wall 11 of the hull 10 by means of a mastic 150 or a resin rope. When a plywood (not shown) is provided on the rear surface of the secondary insulation layer 140 to reinforce the rigidity, the mastic 150 may be made of an epoxy resin, and the plywood may also be formed on the inner wall 11 ).

In the present embodiment, the first wrinkle 210 has a lower withstand-pressure performance than the second wrinkle 220 and has a high flexibility against heat shrinkage.

FIG. 4 is an enlarged view of the first fold shown in FIG. 2, and FIG. 5 is an enlarged view of the second fold shown in FIG.

Referring to FIG. 4, the first corrugation 210 has a convex shape starting from a pair of first corrugation lines C ₁₁ and C ₁₂ . The first wrinkle generation lines C ₁₁ and C ₁₂ extend perpendicular to the boundary points of the first wrinkle 210 and the wrinkle-free flat portion of the primary barrier 110. First it folds the center line (C _L1) may be one pairing of a first creasing line located in the middle of the (C _11, C ₁₂₎ a first creasing line (C _11, C ₁₂₎ and extending parallel.

The first corrugation 210 according to the present embodiment has a structure having three convex peaks 210a, 210b and 210c toward the inner space 101 where the liquefied gas is stored.

Referring to FIG. 5, the second corrugations 220 may have symmetrical shapes on both sides 221 and 222 with respect to the second corrugation center line _L2 . The second corrugation 220 has a structure having one convex peak 220a toward the inner space 101 where the liquefied gas is stored. This second corrugation 220 is a corrugation commonly found in conventional liquefied natural gas storage tanks.

The length of the outer line of the first corrugation 210 is longer than the length of the outline of the second corrugation 220 when comparing the cross sections of the first corrugation 210 and the second corrugation 220 as shown in FIGS.

When the first wrinkle 210 and the second wrinkle 220 have the above-described structure, the first wrinkle 210 has a lower withstand pressure performance than the second wrinkle 220 and has a high flexibility with respect to heat shrinkage.

More specifically, the first wrinkle 210 having a longer contour than the second wrinkle 220 has a greater maximum allowable shrinkage than the second wrinkle 220, without shrinkage. Therefore, the first wrinkle 210 having a longer contour than the second wrinkle 220 may have greater flexibility than the second wrinkle 220 when the heat shrinks.

The first wrinkles 210 having more peaks than the second wrinkles 220 may protrude more than the second wrinkles 220 and may be vulnerable to external forces. Therefore, the first wrinkle 210 having more peaks than the second wrinkles 220 may have a lower withstand pressure performance than the second wrinkles 220.

Referring to FIG. 4, the first corrugation 210 may have a symmetrical shape on both sides with respect to the first corrugation centerline C _L1 .

The first wrinkle 210 has a convex structure toward the inner space 101 where the middle peak portion 210a of the three peak portions 210a, 210b and 210c is lighter than the remaining portions 210b and 210c .

Referring to FIG. 5, the second corrugations 220 may have symmetrical shapes on both sides 221 and 222 with respect to the second corrugation center line _L2 . This second pleat 220 is a wrinkle shape that is common in conventional liquefied natural gas storage tanks.

In the liquefied gas storage tank 100 according to the present embodiment, the first wrinkle 210 having high flexibility against heat shrinkage is formed below the free surface of the liquefied gas stored in the internal space 101, 2 wrinkles 220 are formed on the free surface so that wrinkles are formed in the same manner as the second wrinkles 220 according to the present embodiment, Flexibility can be improved.

Meanwhile, in manufacturing the liquefied gas storage tank 100 according to the present embodiment, the amount of liquefied gas stored according to the operational schedule can be determined, and the position of the free surface of the stored liquefied gas can also be determined.

For example, the amount of storage that is expected to be stored at the highest frequency in the liquefied gas storage tank 100 on a flight schedule can be determined.

For example, the storage amount expected to be stored at the highest frequency in the liquefied gas storage tank 100 on the flight schedule may be determined to be 60% of the total storage amount. At this time, the position of the free surface of the liquefied gas stored in the liquefied gas storage tank 100 can also be determined, so that the formation positions of the first corrugation 210 and the second corrugation 220 can be determined.

For example, the storage amount expected to be stored at the highest frequency in the liquefied gas storage tank 100 may be determined as 100% of the total storage amount. In this case, the free surface of the stored liquefied gas is not formed in the liquefied gas storage tank 100, so that only the first corrugation 210 may be formed in the primary barrier 110.

The first corrugation 210 according to the present embodiment has a structure having three convex peaks 210a, 210b and 210c toward the inner space 101 where the liquefied gas is stored.

However, this is merely an example, and the first corrugation may have a structure having two peak portions or four or more peak portions.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, many modifications and changes may be made by those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims. The present invention can be variously modified and changed by those skilled in the art, and it is also within the scope of the present invention.

10: Hull
100: Liquefied gas storage tank
110: Primary barrier
120: Secondary barrier
130: Primary insulation layer
131: primary unit insulation block
133: Primary insulation packing
135: shock absorbing layer
140: Secondary insulation layer
141: Secondary unit insulation block
143: Secondary insulation packing
200: Wrinkles
210: first wrinkle
220: 2nd wrinkle

Claims (6)

1. A liquefied gas storage tank for storing liquefied gas in an internal space,
Defining the interior space and including a corrugated primary barrier,
Preferably,
A first wrinkle located below the free surface of the liquefied gas stored in the internal space of the primary barrier and a second wrinkle located above the free surface,
The first wrinkle has a lower withstand pressure performance than the second wrinkle, has a high flexibility against heat shrinkage,
The first folds
And a structure having two or more peak portions convex toward the inner space,
The second wrinkle,
And a convex peak portion toward the inner space,
Wherein the length of the outline of the first corrugation is longer than the length of the outline of the second corrugation. delete The method according to claim 1,
The first folds
And a structure having three peak portions convex toward the inner space. The method of claim 3,
The first folds
Both side surfaces have a symmetrical shape with respect to the first wrinkle center line,
The second wrinkle,
And both sides have a symmetrical shape with respect to the second wrinkle center line. The method of claim 3,
The first folds
Wherein a middle peak portion of the three peak portions has a convex structure toward the inner space relative to the rest. A ship or an offshore structure comprising a liquefied gas storage tank according to any one of claims 1, 3, 4 and 5.

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