KR102281934B1 - Liquefied gas storage tank and vessel comprising the same - Google Patents

Abstract

The present invention relates to a liquefied gas storage tank and a vessel comprising the same. The liquefied gas storage tank comprises: a first barrier made of a metal material and forming an accommodating space for accommodating a cryogenic material; a first insulating wall provided on the outside of the first barrier; a second barrier provided on the outside of the first insulating wall and including a main barrier and an auxiliary barrier; and a second insulating wall provided on the outside of the second barrier. The first barrier includes: a plurality of flat portions fixed to the upper surface of the first insulating wall; and a curved portion formed between the plurality of flat portions to form a curved surface toward the accommodating space. The ratio (W/H) of the width (W) to the height (H) of the curved portion is in a range of 2.0 to 3.0 (2.0 <= W/H <= 3.0). Therefore, the burden of thermal stress caused by low temperatures and pressure stress caused by sloshing can be minimized.

Description

Liquefied gas storage tank and vessel comprising the same

The present invention relates to a liquefied gas storage tank and a ship including the same.

According to recent technology development, liquefied gas such as liquefied natural gas (LNG) and liquefied petroleum gas (LPG) is widely used to replace gasoline or diesel.

In addition, in ships that transport or store liquefied gas such as LNG at sea, LNG RV (Regasification Vessel), LNG FPSO (Floating, Production, Storage and Offloading), LNG FSRU (Floating Storage and Regasification Unit), etc. Storage tanks (so-called "cargo holds") are installed for storing LNG in a cryogenic liquid state.

In addition, the liquefied gas storage tank may generate boil-off gas (BOG) due to heat intrusion from the outside, and the natural vaporization rate (BOR), which is the vaporization rate of the boil-off gas through the adiabatic design, is Lowering the liquefied gas storage tank is a key technology. In addition, since the liquefied gas storage tank is exposed to various loads such as sloshing, it may be essential to secure the mechanical strength of the insulation panel.

Considering this point, the thickness range of the primary insulating wall and the secondary insulating wall may be related to the mechanical strength of the liquefied gas storage tank. Accordingly, studies are being actively conducted to remove the low-temperature burden of the secondary barrier while maintaining the mechanical strength of the secondary barrier.

In addition, since the primary barrier is directly exposed to cryogenic materials, a study to optimize the cross-sectional shape of the curved surface to minimize the thermal stress caused by cryogenic temperatures as well as the pressure stress caused by sloshing is being actively carried out.

The present invention was created to solve the problems of the prior art as described above, and an object of the present invention is to optimize the cross-sectional shape of the curved surface of the primary barrier to reduce thermal stress due to low temperature as well as pressure caused by sloshing. To provide a liquefied gas storage tank and a ship including the same to minimize the stress (pressure stress) burden.

In addition, an object of the present invention is to make the thickness of the primary insulating wall the same as or similar to that of the secondary insulating wall in the entire thickness of the insulating wall, thereby maintaining the mechanical strength of the secondary insulating wall at a certain level while maintaining the low temperature burden and slow It is to provide a liquefied gas storage tank and a ship including the same to reduce the burden.

In addition, an object of the present invention is to make the thickness of the primary insulating wall the same as or similar to the secondary insulating wall in the total thickness of the insulating wall, so that the low temperature burden and the sloshing burden of the secondary barrier in the range where brittle fracture of the hull does not occur It is to provide a liquefied gas storage tank and a ship including the same to reduce the

In addition, it is an object of the present invention to provide a liquefied gas storage tank and a ship including the same to improve the configuration of the secondary barrier to increase the thermal insulation performance.

In addition, it is an object of the present invention to provide a liquefied gas storage tank and a ship including the same, which improve the configuration of the fixing member for fixing the secondary insulating wall to the hull, thereby increasing the thermal insulation performance as well as reducing the man-hours.

A liquefied gas storage tank according to an aspect of the present invention includes: a primary barrier made of a metal material to form an accommodating space for accommodating a cryogenic material; a first insulating wall provided on the outside of the first barrier; a secondary barrier provided on the outside of the first insulating wall and comprising a main barrier and an auxiliary barrier; And a liquefied gas storage tank comprising a secondary heat insulating wall provided on the outside of the secondary barrier, wherein the primary barrier is formed between a plurality of flat parts fixed to the upper surface of the primary insulating wall, and the plurality of flat parts and a curved portion forming a curved surface toward the accommodation space, and the ratio (W/H) of the width (W) to the height (H) of the curved portion is in the range of 2.0 to 3.0 (2.0 ≤ W/H ≤ 3.0) characterized.

Specifically, the curved portion includes a horizontal curved portion and a vertical curved portion, the horizontal curved portion and the vertical curved portion are formed to intersect, and the horizontal curved portion and the vertical curved surface The portion may be the same height and width.

Specifically, the curved portion may include a pair of first curved portions connected to each of the adjacent flat portions and having a first radius of curvature r1; a second curved portion forming an upper portion of the curved portion and having at least a second radius of curvature r2 greater than the first radius of curvature r1; and a pair of third curved portions connecting each of the pair of first curved portions and the second curved portion, and having at least a third radius of curvature r3 having a radius greater than the second radius of curvature r2. can

Specifically, the size of the third radius of curvature may be greater than the sum of the size of the second radius of curvature and the size of the first radius of curvature.

Specifically, the ratio (W/H) of the width (W) to the height (H) of the curved portion may be determined based on the thermal stress and the pressure stress at a low temperature of the primary barrier.

Specifically, in the pair of third curved portions, a third center of curvature of one of the third curved portions and a fourth center of curvature of the other third curved portion may be horizontally shifted from the inside of the curved portion.

Specifically, each of the pair of first curved portions has the first radius of curvature between a first connection point connected to the flat portion and a second connection point connected to each of the pair of third curved portions. has a curved surface shape, and the first connection point is the same position as the point where the first circle curve having the first radius of curvature from the first center of curvature on the receiving space side and the vertical center line of the first circle intersect, The second connection point may be located in a curved portion of the first circle within an angle of 30 degrees downward from a point where the curve of the first circle and the horizontal center line of the first circle intersect.

Specifically, the primary barrier may further include a protrusion structure formed on the flat portion within a predetermined distance from an intersection where the horizontal curved portion and the vertical curved portion intersect.

Specifically, the protruding structure may be smaller in size than the horizontal curved portion and the vertical curved portion, and may be formed in a convex circular or arc shape.

Specifically, the center of curvature of the curved portion may be located above the virtual plane formed by the flat portion.

A ship according to another aspect of the present invention is characterized in that it includes the liquefied gas storage tank described above.

A liquefied gas storage tank according to the present invention and a ship having the same, by optimizing the cross-sectional shape of the curved surface of the primary barrier, as well as thermal stress due to low temperature (thermal stress) due to sloshing pressure stress (pressure stress) burden by sloshing can be minimized

In addition, the liquefied gas storage tank according to the present invention and a ship having the same, by configuring the thickness of the first insulation wall to be the same as or similar to that of the second insulation wall in the total thickness of the first insulation wall and the second insulation wall covering the connection insulation wall. , it is possible to maintain the mechanical strength of the secondary barrier at a certain level, as well as reduce the burden of low temperature and sloshing of the secondary barrier, thereby preventing damage to the secondary barrier.

In addition, the liquefied gas storage tank according to the present invention and a ship having the same, by configuring the thickness of the first insulation wall to be the same as or similar to that of the second insulation wall in the total thickness of the first insulation wall and the second insulation wall covering the connection insulation wall. , it is possible to prevent brittle fracture of the hull and reduce the low-temperature burden and sloshing burden of the secondary barrier.

In addition, the liquefied gas storage tank according to the present invention and a ship having the same, by providing an auxiliary heat insulating plate on the lower surface of the connecting heat insulating wall provided in the space between the adjacent primary heat insulating walls forming the unit element, the unit element It is possible to further increase the thermal insulation performance at the connection part of the secondary insulating wall.

In addition, the liquefied gas storage tank and the ship having the same according to the present invention can improve the configuration of the secondary barrier to increase the thermal insulation performance.

In addition, the liquefied gas storage tank according to the present invention and a ship having the same, by applying a non-adhesive elastic insulating material as a leveling member of the second insulation wall between the second insulation wall and the hull, even if the existing mastic and leveling wedge are not used, the hull It is possible to level the deformation part of the tank and increase the thermal insulation performance of the tank.

In addition, the liquefied gas storage tank according to the present invention and a ship having the same, a cleat structure by a protrusion provided to protrude to the outside on the lower side of the unit panel of the secondary insulating wall, and a stud bolt fixed to the hull. By fixing the unit panel of the adjacent secondary insulating wall, it is possible to save man-hours compared to the method of fixing the unit panel with stud bolts by drilling a hole in the secondary insulating wall.

1 is a partial cross-sectional view for explaining a liquefied gas storage tank according to a first embodiment of the present invention.
Figure 2 is a partial perspective view for explaining the liquefied gas storage tank according to the first embodiment of the present invention.
3 is a view for explaining the primary barrier of the liquefied gas storage tank according to the first embodiment of the present invention.
4 (a) and (b) are views showing the tensile force of the secondary barrier according to the thickness change of the primary and secondary thermal insulation walls.
5 to 8 are flow diagrams while varying the thickness of the first insulating wall and the second insulating wall of the first case in order to derive the thickness of the first and second insulating walls of the liquefied gas storage tank according to the first embodiment of the present invention. Figures showing the results of analysis.
9 to 12 show the thickness of the first and second insulation walls of the second case performed to derive the thicknesses of the first and second insulation walls of the liquefied gas storage tank according to the first embodiment of the present invention while varying the thicknesses of the first and second insulation walls; Figures showing the results of the flow analysis.
13 to 16 show the thickness of the first and second insulation walls of the third case performed to derive the thicknesses of the first and second insulation walls of the liquefied gas storage tank according to the first embodiment of the present invention while varying the thicknesses of the first and second insulation walls; Figures showing the results of the flow analysis.
17 to 20 show the thickness of the first and second insulation walls of the fourth case performed to derive the thicknesses of the first and second insulation walls of the liquefied gas storage tank according to the first embodiment of the present invention while varying the thicknesses of the first and second insulation walls; Figures showing the results of the flow analysis.
21 is a graph showing the low-temperature stress of the secondary barrier and the probability of brittle fracture of the hull according to the thickness change of the primary and secondary thermal insulation walls.
22, 23 and 24 are views for explaining various configurations of the secondary barrier of the liquefied gas storage tank according to the first embodiment of the present invention.
25 is a partial cross-sectional view for explaining the right-angled corner structure of the liquefied gas storage tank according to the first embodiment of the present invention.
26 is a partial cross-sectional view for explaining the obtuse corner structure of the liquefied gas storage tank according to the first embodiment of the present invention.
27 is a graph showing the thermal conductivity according to the material used for the primary insulating material and the secondary insulating material of the liquefied gas storage tank of the present invention.
28 is a partial cross-sectional view for explaining a liquefied gas storage tank according to a second embodiment of the present invention.
29 is a partial perspective view for explaining a liquefied gas storage tank according to a second embodiment of the present invention.
30 is a partial cross-sectional view for explaining a liquefied gas storage tank according to a third embodiment of the present invention.
31 is an enlarged view of a main part of a liquefied gas storage tank according to a third embodiment of the present invention.
32 is a view for explaining another embodiment of the primary barrier of the liquefied gas storage tank according to the first, second, and third embodiments of the present invention.
33 is a view for explaining the shape of the primary barrier.
34 (a) and (b) are views for explaining the protruding structure provided on the primary barrier.
35 is a perspective view for explaining the unit barrier of the primary barrier.
36 is a view showing the distribution of Mises stress values (thermal stress and pressure stress) according to the ratio (W/H) of the width of the curved portion to the height of the curved portion of the primary barrier.
37 is a view showing the range of the value of the radius of curvature 'r3-r2-r1' according to the ratio (W/H) of the width of the curved portion to the height of the curved portion of the primary barrier through the optimization simulation of the cross-sectional shape of the primary barrier.
38 (a), (b) and (c) are flow analysis of the sloshing pressure value when the fluid flows into the horizontal and vertical curved surfaces from the primary barrier of the present invention and the primary barrier to be compared. A drawing showing the results.
39 (a) and (b) are diagrams for explaining deformation when a uniformly distributed load is applied to the primary barrier of the present invention and the primary barrier to be compared.

The objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments taken in conjunction with the accompanying drawings. In the present specification, in adding reference numbers to the components of each drawing, it should be noted that only the same components are given the same number as possible even though they are indicated on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

In addition, the accompanying drawings are only for easy understanding of the embodiments disclosed in the present specification, and the technical spirit disclosed herein is not limited by the accompanying drawings, and all changes included in the spirit and scope of the present invention , should be understood to include equivalents or substitutes.

Also, terms including an ordinal number such as 1st, 2nd, etc. may be used to describe various components, but the components are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

Hereinafter, in this specification, liquefied gas may be used to encompass all gas fuels that are generally stored in a liquid state, such as LNG or LPG, ethylene, ammonia, etc. can be expressed as This can be applied to boil-off gas as well. In addition, for convenience, LNG may be used to encompass both NG (Natural Gas) in liquid state as well as LNG in supercritical state, etc., and boil-off gas is used to mean including liquefied boil-off gas as well as gaseous boil-off gas. can

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

1 is a partial cross-sectional view for explaining a liquefied gas storage tank according to a first embodiment of the present invention, Figure 2 is a partial perspective view for explaining a liquefied gas storage tank according to a first embodiment of the present invention. 3 is a view for explaining the primary barrier of the liquefied gas storage tank according to the first embodiment of the present invention.

1 to 2, the liquefied gas storage tank 1 according to the first embodiment of the present invention is provided in a ship and liquefied such as LNG, which is a cryogenic (about -160°C to -170°C) material. gas can be stored.

Although not shown, the ship provided with the liquefied gas storage tank (1) described below is a concept that encompasses offshore structures that float at a certain point on the sea and perform specific tasks in addition to merchant ships that transport cargo from the origin to the destination. let me know In addition, in the present invention, the liquefied gas storage tank (1) puts out that any type of tank for storing liquefied gas is included.

The liquefied gas storage tank (1) is a primary barrier (2) in contact with the liquefied gas, a primary insulating wall (3) installed on the outside of the primary barrier (2), a primary insulating wall (3) installed on the outside The secondary barrier (4) may be configured to include a secondary heat insulating wall (5) disposed on the outside of the secondary barrier (4). The liquefied gas storage tank (1) may be supported on the hull (7) by the mastic (6) installed between the secondary insulating wall (5) and the hull (7).

The liquefied gas storage tank 1 may need to optimize the thickness of the primary insulating wall 3 and the secondary insulating wall 5 in order to optimize the thermal insulation performance and storage capacity. For example, when polyurethane foam is used as the main material for the primary insulating wall (3) and secondary insulating wall (5), the total thickness of the first insulating wall (3) and the thickness of the secondary insulating wall (5) is 250mm to 500 mm. In this regard, it will be described with reference to FIGS. 4 to 20 .

In the above, the liquefied gas storage tank 1 may include a flat surface and a corner structure. For example, a transverse wall in the front-rear direction of the liquefied gas storage tank 1, a floor between the transverse walls, a vertical wall, and a ceiling may correspond to a planar structure. In addition, for example, a structure in which the lateral wall, the floor, the vertical wall, and the ceiling of the liquefied gas storage tank 1 meet may correspond to a corner structure. Here, the corner structure may include an obtuse corner structure or a right angle corner structure. When the thickness of the primary insulating wall 3 or the secondary insulating wall 5 is changed, a change in the obtuse-angled corner structure or the right-angled corner structure may be accompanied. It will be described with reference to FIGS. 25 to 26 .

1 and 2 , the primary barrier 2 forms an accommodating space for accommodating liquefied gas, which is a cryogenic material, and may be made of a metal material. For example, the metal material may be a stainless steel material, but is not limited thereto. The primary barrier (2) can prevent leakage of liquefied gas to the outside together with the secondary barrier (4).

The primary barrier 2 is fixedly coupled to the upper portion of the primary insulating wall 3 by an anchor strip (not shown), and is installed so as to be in direct contact with liquefied gas, which is a cryogenic material stored in the liquefied gas storage tank 1 . can be

Referring to Figure 3, the primary barrier (2), a flat portion (21) in contact with the upper surface of the first thermal insulation wall (3), a curved portion (22) for relieving contraction or expansion stress due to temperature (stress), It may be divided by a boundary portion 23 between the flat portion 21 and the curved portion 22 . For example, it may be formed of a corrugation membrane sheet made of a stainless steel material having a thickness of 1.0 to 1.5 mm, preferably a stainless steel material having a thickness of 1.0 to 1.2 mm. That is, the primary barrier may be formed in a wrinkle shape.

The primary barrier 2 may be formed so that the wrinkle shape has a first radius of curvature R1 and a second radius of curvature R2. That is, the primary barrier 2 of this embodiment forms a first radius of curvature R1 at the boundary 23 between the flat portion 21 and the curved portion 22, and the curved portion 22 has a second radius of curvature. It may be formed to have two types of radii of curvature R1 and R2 constituting (R2). For example, the first radius of curvature R1 may be smaller than the second radius of curvature R2. The primary barrier 2 having a radius of curvature (R1, R2) is easy to inspect for welding because the upper part forms a gentle curve, and also flexibly responds to sloshing because the fluid hitting from the side flows directly. . In this regard, it will be described in more detail with reference to FIGS. 32 to 39 .

In addition, the primary barrier (2) of this embodiment, large corrugation (Large corrugation) and small corrugation (Small corrugation) can be formed to have the same horizontal and vertical wrinkle sizes in the entire area without distinction. That is, since the horizontal and vertical wrinkle sizes are the same in the entire primary barrier 2, the primary barrier can be easily manufactured.

Referring to Figure 1, the primary heat insulating wall (3) is designed to withstand the impact from the outside or liquefied gas sloshing from the inside while blocking heat intrusion from the outside, the primary barrier (2) And it can be installed between the secondary barrier (4).

The primary insulating wall 3 may have a structure in which the primary plywood 31 and the primary insulating material 32 are sequentially stacked to the outside of the primary barrier 2, and the primary plywood 31 It may correspond to the sum of the thickness and the thickness of the primary insulating material 32 . The first insulating wall 3 may be formed to a thickness of 160mm to 250mm, and may correspond to 201mm in the present invention.

The primary plywood 31 may be installed between the primary barrier 2 and the primary insulating material 32 .

The primary plywood 31 may be formed to a thickness of 6.5mm to 15mm. For example, in the present embodiment, it may correspond to a thickness of about 12 mm.

The primary insulating material 32 may be formed of a material having excellent thermal insulation performance and excellent mechanical strength so as to withstand an impact from the outside or an impact caused by liquefied gas sloshing from the inside while blocking heat intrusion from the outside. there is.

The primary insulating material 32 may be formed of polyurethane foam between the primary plywood 31 and the secondary barrier 4, and may correspond to a thickness range of 170 mm to 240 mm. In this embodiment, it may correspond to a thickness of about 189 mm.

Referring to FIG. 1 , a part of the primary thermal insulation wall 3 , the secondary barrier 4 and the secondary thermal insulation wall 5 may be laminated to form a unit element. Here, a part of the primary insulating wall 3 constituting the unit element may be defined as the fixed insulating wall 3b, and the width may be smaller than the width of the secondary insulating wall 5 included in the unit element. . In addition, the fixed insulating wall (3b), the secondary barrier (4) and the secondary insulating wall (5) may be arranged in a pre-fixed state, but is not limited thereto, and each is separated from the liquefied gas storage tank (1). It may also be placed in Due to this, a portion of the secondary barrier 4 may be exposed on both sides of the primary insulating wall 3 . The unit elements may be disposed adjacent to each other, and in this case, the connecting insulating wall 3a may be installed in a space portion between the neighboring primary insulating walls 3 , that is, in a space part where the secondary barrier 4 is exposed.

The secondary barrier (4) can be divided into a main barrier (41) and an auxiliary barrier (42), and the main barrier (41) is installed on the upper part of the secondary thermal insulation wall (5) in a unit element, and the auxiliary barrier (42) is installed between the exposed main barrier 41 and the connection insulating wall 3a. At this time, the auxiliary barriers 42 are provided to interconnect the main barriers 41 provided in the unit elements adjacent to each other. That is, adjacent unit elements may be closed by the auxiliary barrier 42 and the connection insulating wall 3a stacked on the main barrier 41 .

The laminated structure of the portion where the connection insulating wall 3a is provided is described with reference to FIG. 2 . Connection insulation wall (3a) may be provided in a form in which the same or similar connection plywood (31a) and connection insulation material (32a) as described in the first insulation wall (3) constituting the unit element are stacked, in this specification, the first insulation Note that the thermal wall 3 may encompass the connection insulating wall 3a and the fixed insulating wall 3b.

FIG. 2 shows the cross-sectional structure of the plane A-A' of FIG. 1 , and the connection insulating wall 3a may have a structure in which a connection plywood 31a and a connection insulating material 32a are stacked. The thickness of the connection insulating wall 3a may correspond to the sum of the thickness of the connection plywood 31a and the thickness of the connection insulating material 32a.

The connecting plywood (31a) may be formed to a thickness of 6.5mm to 15mm. For example, in the present embodiment, it may correspond to a thickness of about 12 mm.

The connection insulating material 32a may be formed of polyurethane foam between the auxiliary barrier 42 of the connection plywood 31a and the secondary barrier 4, and may correspond to a thickness range of 160mm to 240mm. In this embodiment, it may correspond to a thickness of about 189 mm.

As described above, the first insulating material 32 of the primary insulating wall 3 and the connecting insulating material 32a of the connecting insulating wall 3a may have the same thickness. However, in the case of the connection insulation material 32a of the connection insulation wall 3a, since the auxiliary barrier 42 is further laminated in addition to the main barrier 41 of the secondary barrier 4 at the bottom, the connection of the connection insulation wall 3a The insulating material 32a may have a thickness that is smaller than the thickness of the primary insulating material 32 of the primary insulating wall 3 by the thickness of the auxiliary barrier 42 .

The above-described connection insulating wall (3a), when the unit elements are arranged adjacent to each other, sealing the space portion generated between the adjacent secondary insulating walls (5) together with the auxiliary barrier (42) to block the intrusion of heat from the outside installed to perform its role.

However, since the connecting insulating wall 3a is a structure inserted between the adjacent fixed insulating walls 3b constituting the unit element, it is weak in protecting the secondary barrier 4 under the connecting insulating wall 3a from cryogenic temperatures. Nothing else but to do. Accordingly, there is a high possibility that a problem occurs in the secondary barrier 4 under the connection insulating wall 3a where the main barrier 41 and the auxiliary barrier 42 overlap. Hereinafter, the connection insulation wall 3a will be mainly described.

The secondary barrier (4) may be installed between the primary insulating wall (3) and the secondary insulating wall (5) covering the insulating wall (3a), and the liquefied gas leaks to the outside together with the primary barrier (2) can be prevented from becoming

The secondary barrier 4 at the lower end of the fixed insulating wall 3b includes the main barrier 41 as a single barrier, and the secondary barrier 4 at the lower end of the connecting insulating wall 3a is a main connecting unit element to each other. It may include a barrier 41 and an auxiliary barrier 42 provided on the secondary heat insulating wall 5 constituting the unit element.

The main barrier 41 is provided on the secondary heat insulating wall 5 constituting the unit element and may be formed to a thickness of 0.6 mm to 1.0 mm, and the main barrier 41 adjacent to each other is formed by stacking the auxiliary barriers 42. confidentiality can be achieved. For example, in this embodiment, the main barrier 41 may correspond to a thickness of about 1 mm.

The auxiliary barrier 42 may be formed to a thickness of 0.6 mm to 1.0 mm as a configuration for connecting unit elements to each other and may be laminated on the main barrier 41 . For example, in this embodiment, the auxiliary barrier 42 may correspond to a thickness of about 0.7 mm.

On the other hand, referring to FIGS. 1 and 2 , the secondary heat insulating wall 5, together with the fixed insulating wall 3b and the connecting insulating wall 3a, blocks heat intrusion from the outside while blocking an impact from the outside or from the inside. It can be designed to withstand the impact caused by liquefied gas sloshing. In addition, the secondary thermal insulation wall 5 may be installed between the secondary barrier 4 and the hull 7 , and may include a secondary thermal insulation material 51 and a secondary plywood 52 .

The secondary thermal insulation wall 5 may have a structure in which the secondary thermal insulation material 51 and the secondary plywood 52 are sequentially stacked on the outside of the secondary barrier 4, the thickness of the secondary thermal insulation material 51 And the total thickness of the sum of the thickness of the secondary plywood 52 may be formed to 150mm to 240mm. For example, in this embodiment, the secondary heat insulating wall 5 may correspond to about 199mm.

The secondary insulating material 51 may be formed of a material having excellent thermal insulation performance and excellent mechanical strength so as to withstand an impact from the outside or an impact caused by liquefied gas sloshing from the inside while blocking heat intrusion from the outside. there is.

The secondary insulating material 51 may be formed of polyurethane foam between the secondary barrier 4 and the secondary plywood 52, and may be formed to a thickness of 160 mm to 230 mm. For example, in the present embodiment, it may correspond to a thickness of about 189 mm.

The secondary plywood 52 may be installed between the secondary insulating material 51 and the hull 7 . For example, in addition, the secondary insulating material 51 may be installed in contact with the secondary plywood (52). The secondary plywood 52 may be formed to a thickness of 6.5mm to 25mm. For example, in the present embodiment, it may correspond to a thickness of about 9 mm.

As described above, in the liquefied gas storage tank 1 according to this embodiment, the first insulating wall 3 has a thickness of 66% to 166% of the second insulating wall 5, and The connected insulating wall (3a) to be covered has a thickness of 67% to 167% of the secondary insulating wall (5), so that the connecting insulating wall (3a) has the same or similar thickness as the secondary insulating wall (5). can To be associated with this configuration, the connecting insulating material 32a of the connecting insulating wall 3a is made to have a thickness of 90% to 110% of the secondary insulating material 51, so that the connecting insulating material 32a of the connecting insulating wall 3a is It may be configured to have the same or similar thickness as the secondary insulating material 51 . In this embodiment, if the connection insulating wall 3a is covered, the part of the fixed insulating wall 3b constituting the unit element is not mentioned in detail, but in relation to the secondary insulating wall 5, the fixed insulating wall 3b is also connected and insulating. Note that it is the same as or similar to the wall 3a.

When the connecting insulating wall 3a and the secondary insulating wall 5 or the connecting insulating material 32a and the secondary insulating material 51 of the connecting insulating wall 3a are formed in this thickness ratio, the low temperature of the secondary barrier 4 The upper limit value of the stress in may correspond to 50 MPa or less in the lower portion of the connection insulating wall 3a. In addition, specifically, the stress value at a low temperature of the secondary barrier 4 may be 40 MPa to 50 MPa in the lower portion of the connection insulating wall 3a. These values were obtained according to the results of flow analysis, which will be described later.

In this embodiment, the thickness of the connecting insulating wall 3a and the secondary insulating wall 5 or the thickness of the connecting insulating material 32a and the secondary insulating material 51 of the primary insulating wall 3 are the same or similar. In this regard, it will be described with reference to FIGS. 4 to 20 .

4 (a), (b) is a connection insulation wall (3a) encompassed by the first insulation wall (3) and a secondary barrier (3a) under the connection insulation wall (3a) according to the thickness change of the second insulation wall (5) 4) is a diagram showing the tensile force. It is assumed that the total thickness of the connection insulating wall 3a, the secondary barrier 4, the secondary insulating wall 5 and the like in FIGS. 4A and 4B is the same.

On the other hand, the secondary barrier 4 and the secondary insulating wall 5 have a difference in the amount of self-contraction depending on the temperature to which they are exposed. In the case of the secondary barrier 4 and the secondary insulating wall 5, the connection insulating wall 3a ), the thinner the thickness, the more affected by the cooling and heat of cryogenic liquefied gas. In addition, in this case, there is a problem in that the temperature itself is lowered, the amount of shrinkage itself increases, and the stress at a low temperature increases, thereby increasing the risk of damage to the secondary barrier 4 . This problem may occur especially in the auxiliary barrier 42 that interconnects the main barrier 41 provided in the unit elements adjacent to each other under the connection insulating wall 3a by bonding or the like. Both ends of the auxiliary barrier 42 are connected to the main barrier 41 of each unit element in the lower portion of the connection insulation wall 3a, and as the secondary insulation wall 5 of the unit element contracts, both ends of the auxiliary barrier 42 This is because they can be deformed to move away from or close to each other.

Referring to Figure 4 (a), the connection insulating wall (3a) is formed relatively thinner than the secondary insulating wall (5), the height of the secondary barrier (4) is upward from the center of the total thickness based on the thickness direction. It shows the case where it is located. At this time, in order to reduce the mechanical stress applied to the secondary barrier 4 when the hull is structurally deformed due to the 6 degree of freedom movement of the hull 7, the thickness of the secondary thermal insulation wall 5 is secured 2 The thickness of the heat-blocking wall 5 may be relatively thicker than that of the connection-insulation wall 3a.

Referring to Figure 4 (b), the thickness of the connection insulating wall (3a) and the secondary insulating wall (5) are formed similarly, so that the height of the secondary barrier (4) is the central region of the total thickness based on the thickness direction. It shows the case where it is located. Here, the central region may correspond to 40% to 60% of the total thickness. In this case, compared with (a) of FIG. 4 , the amount of shrinkage itself is reduced, so that the stress at low temperature will be reduced. In addition, compared with (a) of Figure 4, the risk of damage to the secondary barrier will be relatively low.

In the present invention, a liquefied gas storage tank (1) that can reduce the low-temperature burden and sloshing burden of the secondary barrier (4) while maintaining the mechanical strength of the secondary insulating wall (5) at a certain level has been derived. It will be understood by the description with reference to FIGS. 5 to 20 .

5 to 20 are, in order to derive the thickness of the first insulating wall 3 and the second insulating wall 5 encompassing the connection insulating wall 3a of the liquefied gas storage tank 1 according to the present embodiment. Connection insulating wall 3a for each case 1 (FIGS. 5 to 8), the second case (FIGS. 9 to 12), the third case (FIGS. 13 to 16), and the fourth case (FIGS. 17 to 20) It is a diagram showing the results of flow analysis while varying the thickness of the and secondary insulating wall (5). In this embodiment, the thickness of the connecting insulating wall 3a is mainly described, but it should be noted that the thickness of the primary insulating wall 3 is also the same as or similar to that of the connecting insulating wall 3a.

In carrying out the flow analysis for each case, the analysis conditions are as follows.

First, the total thickness of the connection insulating wall 3a and the secondary insulating wall 5 of the first to fourth cases, which are the analysis models, was equally applied to 400 mm.

Second, only the position of the secondary barrier 4 was different by varying the thickness of each of the connection insulating wall 3a and the secondary insulating wall 5 .

Third, considering the same linear temperature distribution conditions, the temperature of the primary barrier (2) position was set to -163 °C, which is the temperature of the liquefied gas, and the temperature at the hull (7) position was set to room temperature (20 °C).

Fourth, by fixing the minimum and maximum values of the stress values, different stresses are indicated by color, for example, red indicates the greatest stress value, and blue indicates that the stress value is smaller.

Fifth, the thickness ratio was defined as the ratio of the thickness of the connecting insulating wall 3a out of the total thickness (400 mm).

Flow analysis of case 1 to case 4, which is an analysis model, was performed under the above analysis conditions.

5 to 8 are the first to derive the thickness of the connecting insulating wall (3a) and the second insulating wall (5) encompassed in the primary insulating wall (3) of the liquefied gas storage tank according to the first embodiment of the present invention. These are drawings showing the results of flow analysis while varying the thickness of the connection insulating wall 3a and the secondary insulating wall 5 of the case.

The first case is a case in which the thickness of the connection insulating wall 3a is 100 mm and the thickness of the secondary insulating wall 5 is 300 mm, as shown in FIG. 5 . That is, in the first case, the ratio of the thickness of the connecting insulating wall 3a among the total thickness (400mm) of the connecting insulating wall 3a and the secondary insulating wall 5 is 0.25, and the secondary barrier 4 is connected It is located close to the primary barrier (2), which is the upper end from the center of the total thickness of the sum of the thicknesses of the insulating wall (3a) and the secondary insulating wall (5).

In the case of this first case, as shown in FIGS. 6 to 8 , as a result of the flow analysis, in a state in which the unit elements are arranged adjacently, a portion of the secondary barrier 4 corresponding between the neighboring secondary insulating walls 5 is It is shown in red, and the stress value was calculated to be 70.12 MPa.

The reason why stress is generated in the secondary barrier 4 in the case of the first case can be seen from FIG. 4 . That is, as the thickness of the connection insulating wall 3a decreases, it is greatly affected by the cooling and heat of the liquefied gas in the secondary barrier 4 .

9 to 12 show the thickness of the connection insulating wall 3a and the secondary insulating wall 5 encompassed by the primary insulating wall 3 of the liquefied gas storage tank according to the first embodiment of the present invention. These are diagrams showing the results of flow analysis while varying the thickness of the connection insulating wall 3a and the second insulating wall 5 of the two cases.

The second case is a case in which the thickness of the connection insulating wall 3a is 160 mm and the thickness of the secondary insulating wall 5 is 240 mm, as shown in FIG. 9 . That is, in the second case, the ratio of the thickness of the connecting insulating wall 3a among the total thickness (400 mm) of the connecting insulating wall 3a and the secondary insulating wall 5 is 0.4, and the secondary barrier 4 is connected It is located slightly biased toward the primary barrier (2) from the center of the total thickness of the sum of the thicknesses of the insulating wall (3a) and the secondary insulating wall (5).

In the case of this second case, as shown in FIGS. 10 to 12 , as a result of the flow analysis, in the state in which the unit elements are arranged adjacently, the secondary barrier (4) portion corresponding between the neighboring secondary thermal insulation walls (5) is It appeared as a yellow system, and the stress value was calculated to be 55.09 MPa.

13 to 16 show the thickness of the connecting insulating wall 3a and the secondary insulating wall 5 encompassed by the primary insulating wall 3 of the liquefied gas storage tank according to the first embodiment of the present invention. These are diagrams showing the results of flow analysis while varying the thickness of the connecting insulating wall 3a and the second insulating wall 5 in three cases.

The third case is a case in which the thickness of the connection insulating wall 3a is 201 mm and the thickness of the secondary insulating wall 5 is 199 mm, as shown in FIG. 13 . That is, in the third case, the ratio of the thickness of the connecting insulating wall 3a among the total thickness (400 mm) of the connecting insulating wall 3a and the secondary insulating wall 5 is about 0.5, and the secondary barrier 4 is It is located adjacent to the center of the total thickness of the sum of the thicknesses of the connecting insulating wall (3a) and the secondary insulating wall (5).

In the case of this third case, as shown in FIGS. 14 to 16 , as a result of the flow analysis, in a state in which the unit elements are arranged adjacent to each other, the secondary barrier 4 corresponding to between the neighboring secondary insulating walls 5 is It appeared as a light sky blue system, and the stress value was calculated to be 47.63 MPa.

17 to 20 show the thickness of the connecting insulating wall 3a and the secondary insulating wall 5 encompassed by the primary insulating wall 3 of the liquefied gas storage tank according to the first embodiment of the present invention. These are drawings showing the results of flow analysis while varying the thicknesses of the connecting insulating wall 3a and the second insulating wall 5 of the four cases.

The fourth case is a case in which the thickness of the connection insulating wall 3a is 240 mm and the thickness of the secondary insulating wall 5 is 160 mm, as shown in FIG. 17 . That is, in the fourth case, the ratio of the thickness of the connecting insulating wall 3a among the total thickness (400 mm) of the connecting insulating wall 3a and the secondary insulating wall 5 is 0.6, and the secondary barrier 4 is connected It is located below from the center of the total thickness of the sum of the thicknesses of the insulating wall (3a) and the secondary insulating wall (5).

In the case of this fourth case, as shown in FIGS. 18 to 20 , as a result of the flow analysis, in a state in which the unit elements are arranged adjacently, a portion of the secondary barrier 4 corresponding between the neighboring secondary insulation walls 5 is It appeared as a light blue system, and the stress value was calculated to be 41.21 MPa.

As described above, as a result of the flow analysis of each of the first to fourth cases, the secondary barrier 4 under the connection insulating wall 3a decreases as the distance from the primary barrier 2 increases, the low-temperature stress due to heat shrinkage decreases. It can be seen that there is a tendency to It will be described with reference to FIG. 21 .

21 is a view showing the relationship between the low-temperature stress of the secondary barrier and the probability of brittle fracture of the hull according to the thickness change of the primary and secondary thermal insulation walls.

As shown in the graph shown in FIG. 21 , in addition to the first to fourth cases, the secondary barrier 4 under the connection insulating wall 3a is further away from the primary barrier 2, It can be predicted that the resulting stress value will decrease. That is, it can be seen that the secondary barrier 4 under the connection insulating wall 3a decreases as the temperature increases as the distance from the primary barrier 2 increases, so that the shrinkage decreases and the stress decreases. In this embodiment, the secondary barrier 4 under the connection insulating wall 3a is mainly described, but the secondary barrier 4 under the fixed insulating wall 3b constituting the unit element is also far from the primary barrier 2 It will be obvious that the stress decreases as the temperature increases. The secondary barrier 4 under the connection insulating wall 3a is a state in which the main barrier 41 and the auxiliary barrier 42 are stacked, and the secondary barrier 4 under the primary insulating wall 3 is the main barrier ( 41) consists of only

The liquefied gas storage tank 1 of this embodiment derived as described above is the second as the thickness of the connecting insulating wall 3a is increased from the total thickness of the sum of the thicknesses of the connecting insulating wall 3a and the secondary insulating wall 5. The temperature received by the barrier 4 rises (reducing the influence of cold heat from the cryogenic liquid gas). Through this, the shrinkage due to the cooling and heat of the secondary barrier 4 itself is reduced, and the stress caused by the cooling is reduced, thereby preventing damage to the secondary barrier 4 due to the cooling and heating. Of course, this principle is also applied to the secondary barrier (4) under the primary insulating wall (3) defined as encompassing the connection insulating wall (3a).

In addition, as the thickness of the connecting insulating wall 3a and the fixed insulating wall 3b increases (the thickness of the secondary insulating wall 5 is relatively decreased), the secondary barrier 4 is formed on the secondary barrier 4 The transmitted sloshing load and the fluid dynamic load are lowered, and the stress caused by the sloshing is reduced, so that damage caused by the sloshing can be prevented. In addition, as the thickness of the secondary thermal insulation wall 5 becomes thinner (the thickness of the primary thermal insulation wall 3 becomes relatively thick), it may be easy to adjust the flatness of the secondary barrier 4 .

In addition, as the thickness of the connecting insulating wall 3a and the fixed insulating wall 3b is increased, the thickness of the secondary insulating wall 5 is relatively decreased, and since it is relatively farther from the primary barrier 2, the secondary insulating wall The shrinkage force due to the cold heat of (5) is also reduced, and the tensile force of the secondary barrier 4 is reduced according to the decrease in the contractile force of the secondary thermal insulation wall 5, so that the secondary barrier 4 is the contractile force of the secondary thermal insulation wall 5. damage can be prevented.

Considering the low-temperature stress of the secondary barrier 4, in the present invention, the connecting insulating wall 3a in the combined thickness of the connecting insulating wall 3a and the secondary insulating wall 5 is arranged to correspond to 40% or more. can Preferably, the liquefied gas storage tank 1 of the present invention has a thickness in the range of the second to fourth cases, that is, the connecting insulating wall 3a is the sum of the connecting insulating wall 3a and the second insulating wall 5 . It can be arranged to correspond to 40% to 60% in. More preferably, the liquefied gas storage tank 1 of the present invention is 47% of the range of the third case, that is, the thickness of the connecting insulating wall 3a is the sum of the connecting insulating wall 3a and the second insulating wall 5 It can be arranged to correspond to to 53%.

However, if the thickness of the connecting insulating wall 3a and the primary insulating wall 3 is increased, the thickness of the secondary insulating wall 5 is relatively decreased. Therefore, the secondary insulating wall 5 has 6 freedoms of the hull 7 It is inevitably vulnerable to mechanical stress applied when the hull 7 is structurally deformed due to the island movement, and accordingly, the degree of mechanical stress transmitted to the secondary barrier 4 through the secondary insulating wall 5 increases. have no choice but to

In addition, in a state in which the liquefied gas is loaded, an emergency condition such as the primary barrier 2 is broken may occur. In this case, since the primary barrier 2 can no longer prevent leakage of the liquefied gas, the liquefied gas may come into contact with the secondary barrier 4 . In addition, when the secondary barrier (4) is in contact with the cryogenic liquefied gas, the temperature of the hull (hull) is lowered, the probability of brittle fracture can be increased. In addition, the lower the temperature, the higher the material strength of the hull is, but the greater the brittleness problem occurs, the higher the probability of brittle fracture. Here, brittle fracture may correspond to a sudden fracture that occurs with little plastic deformation, and may be understood as a brittle crack.

In this regard, referring to FIG. 21 , in an emergency situation, the secondary barrier 4 contacted with cryogenic liquefied gas from the first case to the fourth case approaches the hull, so the probability of brittle fracture increases. That is, in FIG. 21 , the probability of brittle fracture of the hull increases from the first case to the fourth case, that is, as the thickness of the connection insulating wall increases compared to the thickness of the secondary insulating wall 5 . In addition, when the thickness of the connecting insulating wall 3a becomes thicker than the fourth case, the probability of brittle fracture is close to 1 and the hull may be cracked or split.

Therefore, the insulation system of the liquefied gas storage tank 1 should be arranged in consideration of the risk of cracking or destruction of the hull as well as the above-described low-temperature stress. In the present invention, the second to fourth cases in which the secondary barrier 4 is located in the central region of the total thickness of the connection insulation wall 3a and the thickness of the secondary insulation wall 5 are low-temperature stress and side of the hull crack Considering all of them, it may be appropriate. Preferably, it can be seen that the third case is appropriate in terms of low temperature stress and mechanical cracks in the hull. This is not exactly the same as the third case, but the thickness of the first insulating wall 3 and the second insulating wall 5 is the same, or the first insulating wall 3 is 199 mm, and the secondary insulating wall 5 is 201 mm. Also, it can be seen that

Therefore, the present invention reduces the low-temperature stress of the secondary barrier 4 by sufficiently securing the thickness of the connection insulating wall 3a and the primary insulating wall 3, and by appropriately providing the thickness of the secondary insulating wall 4, the hull (7) and the secondary barrier (4) provided with a gap between the secondary barrier (4) to reduce the burden on the structural stress transmitted from the hull (7), the second to fourth cases are appropriate It can be done by example. In addition, the third case among them will correspond to a preferred embodiment when both aspects of low-temperature stress and mechanical strength are considered.

On the other hand, the material of the secondary barrier 4 may be configured in various ways, and in this regard, it will be described with reference to FIGS. 22 to 24 .

22, 23 and 24 are views for explaining various configurations of the secondary barrier of the liquefied gas storage tank according to the first embodiment of the present invention.

As shown in FIG. 22 , the secondary barrier 4 may be formed of a first material having a three-layer structure in which a glass fabric (GC)/aluminum foil (AF)/glass-aramid fabric (GAC) is laminated. .

Glass-aramid fabric (GAC) is a glass fabric (Aramid) material is applied to the (Aramid) material, it can be manufactured by mixing 1 line of aramid per 2 lines of glass fiber (Glass fiber).

This first material may be applied to the auxiliary barrier 42 of the secondary barrier 4, but is not limited thereto, and may be applied to the main barrier 41 of the secondary barrier 4, of course.

As shown in Figure 23, the secondary barrier (4), glass fabric (GC) / aluminum foil (AF) / glass fabric (GC) / aluminum foil (AF) / glass fabric (GC) is laminated 5 layers It may be formed of a second material of the structure.

This second material may be applied to the main barrier 41 of the secondary barrier 4, but is not limited thereto and may also be applied to the auxiliary barrier 42 of the secondary barrier 4, of course.

As shown in Fig. 24, the secondary barrier 4 is made of inorganic basalt fabric extracted from basalt, basalt fabric (BC) / aluminum foil (AF) / basalt fabric (BC) ) may be formed of a third material having a stacked three-layer structure.

This third material may be applied to the main barrier 41 which is the secondary barrier 4, but is not limited thereto, and may be applied to the auxiliary barrier 42 which is the secondary barrier 4, of course.

22 to 24, the secondary barrier 4 of this embodiment may be formed of various materials having a multi-layer structure in which the first member/aluminum foil (AF)/second member are stacked. At this time, at least one of the first member and the second member is a glass fabric (GC), a glass-aramid fabric (GAC), a basalt fabric (BC), or a glass fabric (GC)/aluminum foil (AF)/glass fabric (GC) ) can be

In addition, of course, various materials applied to the secondary barrier 4 may be applied in various combinations to the main barrier 41 and the auxiliary barrier 42 of the secondary barrier 4 .

25 is a partial cross-sectional view for explaining a right-angled corner structure of a liquefied gas storage tank according to a first embodiment of the present invention, and FIG. 26 is an obtuse-angled corner structure of a liquefied gas storage tank according to a first embodiment of the present invention. Some cross-sectional views for

5 to 20, when the thickness of the connection insulation wall 3a or the first insulation wall 3 and the thickness of the second insulation wall 5 are formed in the same and similar ranges, it is assumed to have a more stable insulation system. Confirmed. For example, in the same or similar range, the position of the secondary barrier 4 is 40% to 60% of the total thickness of the connection insulating wall 3a or the sum of the thicknesses of the primary insulating wall 3 and the secondary insulating wall 5 It can be shown if it is located in . Such a configuration can be equally applied to the right-angled corner structure of the liquefied gas storage tank 1 shown in FIG. 25 and the obtuse-angled corner structure of the liquefied gas storage tank 1 shown in FIG. 26 .

However, in the right-angled corner structure and obtuse-angled corner structure of the liquefied gas storage tank (1), the secondary barrier (4) has no choice but to be formed in a curved shape, and if it is formed in a curved shape, it is vulnerable to the load caused by the surrounding environment compared to the straight part, The present embodiment can relieve stress caused by such a load. In addition, this embodiment may be easy to absorb the hull deformation.

Referring to FIG. 25, in the right-angled corner structure, the secondary barrier 4 has a radius of curvature of 25% or more compared to the thickness of the primary insulating wall 3 as the thickness of the primary insulating wall 3 is increased to 201 mm, For example, it accounts for 25% to 50%.

In addition, in the right-angled corner structure, the secondary barrier 4 is moved to the hull 7 side compared to the existing thin primary thermal insulation wall as the thickness of the primary thermal insulation wall 3 is increased to 201 mm. In this case, the radius of curvature increases, and as the radius of curvature increases, the length (L1) of the secondary barrier scab part not glued to the secondary barrier 4 is also increased. do. This means an increase in flexibility of the secondary barrier 4 in the right-angled corner structure, whereby the secondary barrier 4 in the right-angled corner structure absorbs peripheral deformations, for example, hull deformation is facilitated, and low-temperature stress is also reduced. will do For example, the length L1 of the non-adhesive portion may be 100 mm to 200 mm.

Referring to FIG. 26, in the obtuse-angled corner structure, the secondary barrier 4 has a radius of curvature of 15% or more compared to the thickness of the primary insulating wall 3 as the thickness of the primary insulating wall 3 is increased to 201 mm, For example, 15% to 35%.

In addition, in the obtuse-angled corner structure, the secondary barrier 4 is moved to the hull 7 side compared to the existing thin first insulating wall as the thickness of the primary thermal insulation wall 3 is increased to 201 mm, and the radius of curvature is increased. it gets bigger In this case, as the radius of curvature of the secondary barrier 4 increases, the length L1 of the secondary barrier scab part not glued to the secondary barrier 4 also increases. do. This means an increase in the flexibility of the secondary barrier 4 in the right-angled corner structure, whereby the secondary barrier 4 in the obtuse-angled corner structure absorbs peripheral deformations, for example, hull deformation is facilitated, and low-temperature stress is also reduced. will do For example, the length L1 of the non-adhesive portion may be 50 mm to 90 mm.

As described above, the secondary barrier 4 in the right-angled corner structure and the obtuse-angled corner structure of the present invention is applied to the existing secondary barrier compared to the right-angled corner structure and the obtuse-angled corner structure of the primary insulating wall formed with a relatively thin thickness. Stress at low temperatures can be reduced. In addition, the non-adhesive portion increases, so it is easy to absorb the hull deformation.

27 is a graph showing thermal conductivity according to the materials used for the primary and secondary insulating materials of the liquefied gas storage tank.

In the liquefied gas storage tank 1 according to the embodiment of the present invention described above, the primary insulating materials 32 and 32a of the connecting insulating wall 3a and the primary insulating wall 3 and the secondary of the secondary insulating wall 5 Each of the insulating materials 51 has been described to be formed of the same polyurethane foam material, but in some cases, polyurethane foams having different materials may be selectively used.

Specifically, the reinforced polyurethane foam (RPUF) is produced by mixing polyol, isocyanate, and a blowing agent, and HFC-245fa or CO ₂ may be used as the blowing agent. HFC-245fa may be relatively expensive compared _{to CO 2 .}

In the case of this embodiment, the primary insulation material (32, 32a) _{is formed of a reinforced polyurethane foam using CO 2} as a foaming agent, and the secondary insulation material 51 is formed of a reinforced polyurethane foam using a foaming agent HFC-245fa. .

Looking at the thermal conductivity characteristics of the blowing agent HFC-245fa and the blowing agent CO ₂ with reference to the graph of FIG. 27, the blowing agent HFC-245fa has a _{lower thermal conductivity value at room temperature compared to the blowing agent CO 2} , but the same or similar value toward the cryogenic temperature see.

That is, the thermal conductivity values of the blowing agent HFC-245fa and the blowing agent CO ₂ show the same or similar values at temperatures below -80 ° C., and the blowing agent HFC-245fa at the above temperature shows a lower value than the _{blowing agent CO 2 .}

Accordingly, in this embodiment, the relatively expensive foaming agent HFC-245fa is not used for both the primary insulation materials 32 and 32a and the secondary insulation material 51, and in consideration of economic aspects, the primary The insulating materials 32 and 32a may _{be formed of a reinforced polyurethane foam in which CO 2} is used as a foaming agent, and the secondary insulation 51 may be formed of a reinforced polyurethane foam in which the foaming agent HFC-245fa is used.

28 is a partial cross-sectional view for explaining the liquefied gas storage tank according to the second embodiment of the present invention, Figure 29 is a partial perspective view for explaining the liquefied gas storage tank according to the second embodiment of the present invention.

28 to 29, the liquefied gas storage tank 1 according to the second embodiment of the present invention is a primary barrier 2 in contact with the liquefied gas from the inside, the primary barrier 2 The primary insulating wall 3 and the connecting insulating wall 3a, the primary insulating wall 3 and the connecting insulating wall 3a installed outside the secondary barrier 4, the secondary barrier 4 It may be configured to include a secondary heat insulating wall 5 disposed on the outside and fixed to the hull 7, and the configuration of the connection insulating wall 3a is different from that of the first embodiment described above, and other configurations are the same Or, since they are similar, only the different parts will be described in order to avoid overlapping description hereinafter.

In this embodiment, as compared with the above-described first embodiment, the configuration of the connecting heat insulating wall 3a may be different.

Specifically, as compared with the above-described first embodiment, the connection insulating wall 3a may further include an auxiliary insulating plate 33 .

That is, the connection insulation wall 3a may have a structure in which the connection plywood 31a, the connection insulation material 32a, and the auxiliary insulation plate 33 are stacked.

The auxiliary heat insulating plate 33 may have a thickness of 5mm to 10mm, and is made of plywood, high-density polyurethane foam (HD PUF), FRP (Fiber Reinforced Plastic), etc. to obtain the load dispersing effect of the secondary barrier 4 can Alternatively, the auxiliary heat insulating plate 33 may be made of VIP (Vacuum Insulation Panel), LD PUF, or the like having excellent thermal insulation properties to compensate for the insulation vulnerability in the portion where the connection insulating wall 3a is formed.

The connecting insulating material 32a of the connecting insulating wall 3a and the primary insulating material 32 of the fixed insulating wall 3b constituting the unit element may have the same thickness as 189 mm. However, in the case of the connection insulating wall 3a, an auxiliary barrier 42 is further laminated in addition to the main barrier 41 of the secondary barrier 4 at the bottom, and also includes an auxiliary heat insulating plate 33, so the connection insulating wall ( The thickness of the connecting insulating material 32a of 3a) may be smaller than the primary insulating material 32 of the primary insulating wall 3 by 0.7 mm in thickness of the auxiliary barrier 42 and 5 mm to 10 mm in thickness of the secondary insulating plate 33 there is.

The auxiliary heat insulating plate 33 described above may be installed not only under the connecting insulating material 32a of the connecting insulating wall 3a but also below the primary insulating material 32 of the primary insulating wall 3 constituting the unit element. am.

30 is a partial cross-sectional view for explaining a liquefied gas storage tank according to a third embodiment of the present invention, Figure 31 is an enlarged view of a main part of the liquefied gas storage tank according to the third embodiment of the present invention.

30 to 31, the liquefied gas storage tank 1 according to the third embodiment of the present invention is a primary barrier 2 in contact with the liquefied gas from the inside, the primary barrier 2 The primary insulating wall 3 and the connecting insulating wall 3a, the primary insulating wall 3 and the connecting insulating wall 3a installed outside the secondary barrier 4, the secondary barrier 4 The second insulation wall 5 disposed on the outside and fixed to the hull 7, the leveling member 8 installed between the second insulation wall 5 and the hull 7, and the second insulation wall 5 are attached to the hull (7) It may be configured to include a fixing member 9 for fixing to, and the leveling member 8 and the fixing member 9 are different from the first embodiment described above, and other configurations are the same or similar, so that in the following In order to avoid overlapping description, only the leveling member 8 and the fixing member 9, which are components different from those of the first embodiment, and parts that are different therefrom will be described.

The leveling member 8 may be installed between the secondary heat insulating wall 5 and the hull 7 .

The leveling member 8 is a non-adhesive elastic insulating material that can level the deformed portion of the hull 7, increase the thermal insulation performance of the tank, and support the secondary thermal insulation wall 5, and EPS (Expanded Polystyrene) etc.

The leveling member 8, the upper surface in close contact with the secondary heat insulating wall 5 by the elastic force becomes flat, and the lower surface in close contact with the hull 7 may have a curved surface to fit the deformation of the hull 7 . Deformation of the hull 7 may occur, for example, during interblock welding of the hull 7 .

That is, the leveling member 8 can level the deformed portion of the hull without using the existing mastic and leveling wedge, and can increase the thermal insulation performance of the tank.

The fixing member 9 may have a cleat structure including a protrusion 91 and a stud bolt 92 so as to fix the secondary heat insulating wall 5 to the hull 7 .

The protrusion 91 may be provided to protrude from both side lower portions of the unit panel of the secondary heat insulating wall 5 to the outside, and may be formed of plywood.

The protrusion 91 is fixed over some side of the secondary insulating material 51 from one side to the side of the secondary plywood 52 of the secondary thermal insulation wall 5 and from the secondary plywood 52 to a certain height. Can be installed, the lower surface forms the same level as the lower surface of the secondary plywood (52).

The width and thickness of the protrusions 91 may be such that the stud bolts 92 can be inserted between the protrusions 91 facing each other when a plurality of unit panels constituting the secondary heat insulating wall 5 are disposed.

The stud bolts 92 may be fixed to the hull 7 .

The stud bolts 92 are fixed to the hull 7 so as to match the space between the unit panels of the neighboring secondary insulating walls 5 when a plurality of unit panels constituting the secondary thermal insulation wall 5 are arranged. can

The stud bolt 92 is provided on each side of the unit panel of the adjacent secondary insulating wall 5 and is positioned between the two opposing protrusions 91 by tightening the bolts to secure the secondary insulating wall 5 to the hull. (7) can be fixed.

As described above, in this embodiment, the thickness of the first heat insulating wall 3 and 3a from the total thickness of the first heat insulating wall 3 and the second heat insulating wall 5 encompassing the connecting heat insulating wall 3a is the second heat insulating wall 5 By configuring the same or similar to that, it is possible to maintain the mechanical strength of the secondary barrier 5 at a certain level, as well as reduce the low temperature burden and the sloshing burden of the secondary barrier 4, ) to prevent damage.

In addition, in this embodiment, by providing an auxiliary heat insulating plate 33 on the lower surface of the connecting heat insulating wall 3a provided in the space between the adjacent primary heat insulating walls 3 constituting the unit element, the adjacent 2 It is possible to further increase the thermal insulation performance at the connection portion of the barrier thermal wall 5 .

In addition, the present embodiment can improve the configuration of the secondary barrier 4 to increase the thermal insulation performance.

In addition, in this embodiment, by applying a non-adhesive elastic insulating material as the leveling member 8 of the secondary insulating wall 5 between the secondary insulating wall 5 and the hull 7, the existing mastic and leveling wedge are not used. Even if it is not, it is possible to level the deformed portion of the hull 7, and it is possible to increase the thermal insulation performance of the tank.

In addition, in this embodiment, a cleat structure by a protrusion 91 provided to protrude to the outside under the side of the unit panel of the secondary heat insulating wall 5 and a stud bolt 92 fixed to the hull 7 . By fixing the unit panel of the adjacent secondary insulating wall 5 in this way, it is possible to reduce the man-hour compared to the method of fixing the unit panel with stud bolts by punching a hole in the secondary insulating wall 5 .

The present invention is not limited to the embodiments described above, and a combination of the embodiments or a combination of at least one of the embodiments and a known technology may be included as another embodiment. For example, the embodiment of FIGS. 28 to 29 can be combined with the embodiment of FIGS. 4 to 27 . Also, for example, the embodiment of FIGS. 30 to 31 can be combined with the thermal insulation system of FIGS. 1 and 2 or the thermal insulation system of FIGS. 28 and 29 .

Hereinafter, the shape of the primary barrier of the liquefied gas storage tank described above will be described in detail with reference to FIGS. 32 to 39 .

32 is a view for explaining another embodiment of the primary barrier of the liquefied gas storage tank according to the first, second, and third embodiments of the present invention, and FIG. 33 is a view for explaining the shape of the primary barrier .

32 to 33, the primary barrier 2 of the liquefied gas storage tank 1 according to the first, second, and third embodiments of the present invention is of two types described with reference to FIG. The cross-sectional shape may be different from that of the primary barrier 2 formed to have a radius of curvature R1 and R2, which will be described in detail below.

Referring to FIG. 32 , the primary barrier 2 includes a plurality of flat portions 21 in contact with the upper surface of the primary thermal insulation wall 3 , and a plurality of curved portions for relieving contraction or expansion stress due to temperature. (22) can be made.

The curved portion 22 of this embodiment has a ratio (W/H) of the width (W) between the adjacent flat portions 21 to the height (H) from the flat portion 21 to the upper end of the curved portion 22 . to have a cross-sectional shape in the range of 2.0 to 3.0 (2.0 ≤ W/H ≤ 3.0) to minimize thermal stress due to low temperature as well as pressure stress burden due to sloshing .

At this time, the width (W) of the curved portion 22 may be 50mm ~ 105mm, preferably 65mm ~ 93mm, more preferably 70mm ~ 80mm, the height (H) of the curved portion 22 is 30mm ~ 50mm, Preferably it may be 30mm ~ 45mm, more preferably 33mm ~ 40mm.

The plurality of curved portions 22 may be formed to cross the horizontal and vertical directions, and the horizontal curved portion 22 and the vertical curved portion 22 may have the same size. That is, since the size of the horizontal and vertical curved portions 22 in the entire primary barrier 2 is the same, the primary barrier can be easily manufactured.

In addition, the plurality of curved portions 22, the interval between the adjacent curved portions 22 is wider than a known one (herein, a known one may be used as a term 'comparison object' hereinafter) is wider, for example , it can be made to have a gap of 350mm to 400mm. Here, the interval between the curved portions 22 may correspond to the interval between the uppermost points of the curved portion 22 . In addition, the size of the plurality of unit barriers 2a constituting the primary barrier 2 is a larger 3:1 ratio than known as shown in FIG. 35 , for example, the length is 3,150 mm to 3,600 mm, and the width It can be formed in a size of 1,050 mm to 1,200 mm.

As such, it is possible to increase the size of the unit barrier 2a by widening the interval between the curved portions 22 in the primary barrier 2 of the present embodiment, from the above-described flat portion 21 to the curved portion 22 ) to the upper end of the curved portion (W/H) of the width (W) between the adjacent flat portions 21 to the height (H) in the range of 2.0 to 3.0 (2.0 ≤ W/H ≤ 3.0) ( 22), and will be further understood by referring to FIGS. 36 to 39 .

Meanwhile, as shown in FIG. 2 , the horizontal curved portion and the vertical curved portion may be formed to cross each other. In this case, the horizontal curved portion and the vertical curved portion may be formed to have the same height and width, respectively.

Also, the curved portion 22 may be formed in a cross-sectional shape having the first, second, and third curved portions 22a, 22b, and 22c having different radii of curvature.

The first curved portion 22a is connected to each of the adjacent flat portions 21 to form a pair, and has a first radius of curvature r1. The first radius of curvature r1 may be 4 mm to 12 mm.

Each of the pair of first curved portions 22a has a first connection point P1 connected to the flat portion 21 and a second connection point P2 connected to each of the pair of third curved portions 22c. ) may have a curved shape having a first radius of curvature r1 between them.

Here, the first connection point (P1) is the lowermost curved portion of the first circle (A1) having the first radius of curvature (r1) from the first center of curvature (C1) on the receiving space side and the length of the first circle (A1) It may be the same position as the point where the center line intersects. The first center of curvature C1 of the first curved portion 22a may be located above the virtual plane formed by the flat portion 21 .

The second connection point P2 is located on the curved portion of the first circle A1 within an angle of 30 degrees downward from the point where the curve of the first circle A1 and the horizontal center line of the first circle A1 intersect. can

The second curved portion 22b forms an upper portion of the curved portion 22 and has at least a second radius of curvature r2 greater than the first radius of curvature r1. Here, the second radius of curvature r2 may be 7 mm to 15 mm.

The second curved portion 22b includes a third connection point P3 connected to any one of the third curved portions 22c among the pair of third curved portions 22c, and the other third curved portion ( 22c) may be in a curved shape having a second radius of curvature r2 between the fourth connection points P4 connected to it.

Here, each of the third connection point P3 and the fourth connection point P4 is a vertical center line of the second circle A2 having a second radius of curvature r2 from the second center of curvature C2 on the opposite side of the receiving space. It may be positioned at a predetermined angle on both sides of the , for example, a curved portion of the second circle A2 between 3 and 10 degrees. The second center of curvature C2 of the second curved portion 22b may be located above the virtual plane formed by the flat portion 21 .

The third curved portion 22c is formed as a pair connecting each of the pair of first curved portions 22a and the second curved portion 22b, and has at least a second radius greater than the second radius of curvature r2. 3 has a radius of curvature r3. Here, the third radius of curvature r3 may be 25 mm to 45 mm.

That is, the size of the first, second, and third radius of curvature r1, r2, r3 of each of the first, second, and third curved portions 22a, 22b, and 22c is 'first radius of curvature (r1) ≤ second radius of curvature. (r2) < the third radius of curvature (r3)'. In this embodiment, the size of the third radius of curvature r3 may be greater than the sum of the size of the second radius of curvature r2 and the size of the first radius of curvature r1.

The third curved portion 22c of any one of the pair of third curved portions 22c is a second connection to which any one of the first curved portions 22a of the pair of first curved portions 22a is connected. It may have a curved shape having a third radius of curvature r3 between the point P2 and the third connection point P3 to which one side of the second curved portion 22b is connected.

Any one of the third curved portions 22c may be provided on a curved portion of the third circle A3 having a third radius of curvature r3 from the third center of curvature C3 on the opposite side of the accommodation space.

In addition, the third curved portion 22c of the other one of the pair of third curved portions 22c is a first curved portion 22a connected to the other of the pair of first curved portions 22a. It may have a curved shape having a third radius of curvature r3 between the second connection point P2 and the fourth connection point P4 to which the other side of the second curved portion 22b is connected.

Another third curved portion 22c may be provided on a curved portion of the fourth circle A4 having a third radius of curvature r3 from the fourth center of curvature C4 on the opposite side of the accommodation space.

In the above, each of the second, third, and fourth connection points P2, P3, and P4 is a pair of third curved portions 22c, respectively, when the position is viewed, the second connection point P2 is a pair of The curve of the first circle A1 of the first curved portion 22a of any one of the first curved portions 22a and the third circular curve, or the other first curved surface of the pair of first curved portions 22a It may be a point where the curve of the first circle A1 and the curve of the fourth circle A4 of the portion 22a meet.

Also, the third connection point P3 may be a point where the curve of the second circle A2 and the curve of the third circle A3 meet. The third connection point P3 may be the same position as a point where the uppermost curved portion of the third circle A3 and the vertical center line of the third circle A3 intersect.

The fourth connection point P4 may be a point where the curve of the second circle A2 and the curve of the fourth circle A4 meet. The fourth connection point P4 may be the same position as a point where the uppermost curved portion of the fourth circle A4 and the vertical center line of the fourth circle A4 intersect.

The pair of third curved portions 22c has a third radius of curvature r3 of the same size, and is different from the third center of curvature C3 of any one third curved portion 22c. The fourth center of curvature C4 of the three curved portion 22c may be shifted in the horizontal direction. In addition, the third and fourth centers of curvature C3 and C4 of the present embodiment are located inside the curved portion 22 . Accordingly, when the third and fourth centers of curvature C3 and C4 are connected by an imaginary line between the adjacent planar parts 21 , they are located inside the curved part 22 , which is above the imaginary line. That is, the third and fourth centers of curvature C3 and C4 of the third curved portion 22c may be located above the virtual plane formed by the flat portion 21 .

As described above, all the centers of curvature C1 , C2 , C3 , and C4 of the curved portion 22 of the present embodiment may be located above the virtual plane formed by the flat portion 21 .

34 (a) and (b) are views for explaining the protruding structure provided on the primary barrier.

The primary barrier 2 of this embodiment, as shown in FIGS. 34 (a) and (b), the peripheral planar portion 21 of the intersection where the horizontal curved portion 22 and the vertical curved portion 22 intersect. ) may further include a protruding structure 24 . For example, the protrusion structure 24 may be provided within a predetermined distance from the intersection. In addition, the predetermined distance may correspond to 1/3 of the distance between intersections located on the same line, but is not limited thereto.

The protruding structure 24 is smaller in size than the horizontal curved portion 22 and the vertical curved portion 22, and has a convex circular shape as shown in (a) of FIG. 34 or as shown in (b) of FIG. It may be formed in various shapes such as an arc shape.

The protruding structure 24 may further minimize a pressure stress burden due to sloshing at a portion where the horizontal curved portion 22 and the vertical curved portion 22 intersect.

35 is a perspective view for explaining the unit barrier of the primary barrier.

The primary barrier 2 according to this embodiment can make the interval between the adjacent curved portions 22 to be a distance of 350 mm to 400 mm wider than known, and thereby 1 as shown in FIG. The size of each of the plurality of unit barriers 2a constituting the barrier 2 is larger than the known 3:1 ratio, for example, a length of 3,150 mm to 3,600 mm and a width of 1,050 mm to 1,200 mm. can be formed In this embodiment, by increasing the size of the unit barrier (2a), the number of installations of the unit barrier (2a) can be reduced compared to the existing one, and the installation man-hours of the primary barrier (2) can be reduced.

In addition, in the unit barrier 2a shown in FIG. 35 , the width between the uppermost ends of the curved portion 22 may correspond to 350 mm to 400 mm. Here, the uppermost end of the curved portion 22 may correspond to the uppermost end of the second curved portion 22b of FIG. 32 . This is an increase in the width between the uppermost ends of the curved portion compared to the comparative unit barrier (known unit barrier), and may be easier to produce and install than the comparative unit barrier. In addition, since the unit barrier 2a according to the embodiment of the present invention has the same width and height of the horizontal curved portion 22 and the vertical curved portion 22, the manufacturing cost is lower than that of the comparative unit barrier. can save

36 is a view showing the distribution of Mises stress values (thermal stress and pressure stress) according to the ratio (W/H) of the curved surface width to the curved surface height of the primary barrier, and FIG. 37 is the cross-sectional shape of the primary barrier It is a diagram showing the range of the value of the radius of curvature 'r3-r2-r1' according to the ratio (W/H) of the width of the curved part to the height of the curved part of the primary barrier through optimization simulation.

The primary barrier 2 of this embodiment is, as described above, to minimize the thermal stress caused by low temperature as well as the pressure stress burden caused by sloshing. The ratio (W/H) of the width (W) between the adjacent flat portions 21 to the height (H) from the flat portion 21 to the upper end of the curved portion 22 in the cross-sectional shape (W/H) ranges from 2.0 to 3.0 (2.0 ≤ W/H ≤ 3.0), and in addition, the first, second, and third radii of curvature (r1, r2, r3) of each of the first, second, and third curved surfaces 22a, 22b, 22c are different from each other, The size of the third radius of curvature r3 was made larger than the sum of the size of the second radius of curvature r2 and the size of the first radius of curvature r1. It was obtained by the experimental data shown in FIG. 39, and in addition to this, a known primary barrier was compared as a comparison object.

Here, the primary barrier to be compared has a large corrugation and a small corrugation, unlike the primary barrier 2 of the present invention.

As shown in FIG. 36 , the present Mises stress (Von) according to the ratio (W/H) of the width (W) of the curved portion 22 to the height (H) of the curved portion 22 of the primary barrier 2 (W/H) Mises Stress), when considering both thermal stress and compressive stress, in the primary barrier (2) of the present invention, the ratio of height to width (W/H) was concentrated in the range of 2.0 to 3.0, thermal stress and compressive stress, In the case of the primary barrier for comparison, the ratio of height and width (W/H) of each large corrugation and small corrugation was about 1.5 or less, and there was a significant difference in thermal stress and compressive stress. That is, the present invention having a height and width ratio (W/H) in the range of 2.0 to 3.0 has good thermal stress and pressure stress compared to a comparative object having a height and width ratio (W/H) of 1.5 or less Could know.

Specifically, in the present invention, the thermal stress increases in proportion to the size of the ratio (W/H) of the height and width of the primary barrier (2), and the compressive stress is the ratio (W) of the height and width of the primary barrier (2) /H) decreases in inverse proportion to the size, and when the height and width ratio (W / H) is in the range of 2.0 to 3.0, the distribution of thermal stress and pressure stress is concentrated, and at this time, the primary barrier (2) of the present invention is It can be seen that the thermal stress and the compressive stress are between 110 MPa and 210 MPa.

On the other hand, in the comparison target, the maximum thermal stress was about 73 MPa and the maximum compressive stress was about 310 MPa in the large corrugation where the ratio (W/H) of the height to the width of the primary barrier was about 1.5 or less, and the height and the height of the primary barrier were about 310 MPa. The maximum thermal stress and the maximum compressive stress were about 150 MPa in the small corrugation where the width ratio (W/H) was 1.5 or less.

In addition, as shown in FIG. 37, in the present invention, the ratio (W/H) of the height and width of the primary barrier 2 is in the range of 2.0 to 3.0, and the radius of curvature 'r3-r2-r1' value is 10 mm ~ In the 30 mm range, preferably 15 mm to 27 mm, the cross-sectional shape optimization result of the primary barrier 2 was obtained.

On the other hand, when the ratio of the height and width (W/H) of the large corrugation and the small corrugation of the primary barrier is less than about 1.5, the value of the radius of curvature of the large corrugation 'r3-r2-r1' is It was about 48 mm, and the 'r3-r2-r1' value of the radius of curvature of the small corrugation was about 21 mm, from which it can be seen that the comparative primary barrier is different from the cross-sectional shape of the primary barrier 2 of the present invention.

On the other hand, the primary barrier (2) of the present invention has a yield stress of 170Mpa at room temperature, and about 220Mpa at a low temperature of -170°C. Therefore, a range not exceeding 170Mpa to 180MPa is required because it is manufactured at room temperature.

Accordingly, the primary barrier 2 of this embodiment has a height and width ratio (W/H) in the range of 2.0 to 3.0, and 170 MPa or less so that the thermal stress or the pressure stress does not exceed about 170 MPa and is differentiated from the comparison target. It may be desirable to have a shape in which the 'r3-r2-r1' value is in the range of 15 mm to 27 mm.

38 (a), (b) and (c) are flow analysis of the sloshing pressure value when the fluid flows into the horizontal and vertical curved surfaces from the primary barrier of the present invention and the primary barrier to be compared. As a drawing showing the results, at this time, the velocity of the fluid flowing into the horizontal and vertical curved portions was set at a speed of 5 m/s. 38 (a) is a flow analysis for the sloshing pressure value when the fluid flows into the horizontal or vertical curved portion 22 from the primary barrier 2 of the present invention, and the maximum sloshing pressure value of 0.31 KPa was obtained . In addition, (b) of FIG. 38 is a flow analysis for the sloshing pressure value when the fluid flows into the horizontal curved portion (large corrugation) from the primary barrier of the comparison object. The maximum sloshing pressure value of 10.52 KPa was obtained, 38 (c) is a flow analysis for the sloshing pressure value when the fluid flows into the vertical curved portion (small corrugation) from the primary barrier of the comparison object, and the maximum sloshing pressure value of 3.58 KPa was obtained.

Here, as described above, the primary barrier 2 of the present invention has a cross-sectional shape having the same size and height of the horizontal and vertical curved portions 22, but the primary barrier for comparison has a general curved cross-sectional shape. A large horizontal curved portion (large corrugation) and a small vertical curved portion (small corrugation) intersect, and the primary barrier 2 of the present invention has a sloshing pressure value compared to the primary barrier of the comparison object. It can be seen that the horizontal curved portion is excellent, and the vertical curved portion is very excellent.

39 (a) and (b) show the deformation when a uniformly distributed load is applied to the primary barrier of the present invention and the primary barrier of the comparison object (the result of structural analysis by sloshing impact pressure is shown). , at this time, a total impact pressure of 10 bar was applied to the primary barrier to perform a elastoplastic structural analysis. This is to understand the dynamic behavior and the amount of plastic deformation in the cross-sectional shape of the primary barrier. The cross-sectional shape of the curved portion 22 of the primary barrier 2 of the present invention shown in FIG. 39 (a) is the curved portion (large corrugation) of the primary barrier for comparison shown in FIG. 39 (b). ), the slope is gentler than the cross-sectional shape, so it can be seen that almost no deformation occurs in the primary barrier 2 of the present invention, and a large amount of deformation occurs in the primary barrier of the comparison object. As such, in the case of the primary barrier to be compared, additional work is required, such as inserting an implant such as a wood wedge or metal at the bottom of the curved part to prevent deformation.

Although the present invention has been described in detail through specific examples, this is for the purpose of describing the present invention in detail, and the present invention is not limited thereto, and by those of ordinary skill in the art within the technical spirit of the present invention. It will be clear that the transformation or improvement is possible.

All simple modifications and variations of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be made clear by the appended claims.

1: Liquefied gas storage tank 2: Primary barrier
2a: unit barrier 21: flat part
22: curved portion 22a: first curved portion
22b: second curved portion 22c: third curved portion
23: boundary 24: protruding structure
3: primary insulating wall 3b: fixed insulating wall
31: primary plywood 32: primary insulation material
3a: connecting insulation wall 31a: connecting plywood
32a: connection insulation material 33: auxiliary insulation plate
4: secondary barrier 41: main barrier
42: auxiliary barrier GAC: glass-aramid fabric
AF: aluminum foil GC: glass fabric
BC: Basalt fabric 5: Second insulation wall
51: secondary insulation 52: secondary plywood
6: Mastic 7: Hull
8: leveling member 9: fixing member
91: protrusion 92: stud bolt
A1: first circle A2: second circle
A3: 3rd circle A4: 4th circle
C1: first center of curvature C2: second center of curvature
C3: Third center of curvature C4: Fourth center of curvature
P1: first connection point P2: second connection point
P3: 3rd connection point P4: 4th connection point
r1: first radius of curvature r2: second radius of curvature
r3: third radius of curvature

Claims (11)

a first barrier made of a metal material to form an accommodating space for accommodating the cryogenic material;
a first insulating wall provided on the outside of the first barrier;
a secondary barrier provided on the outside of the first insulating wall and comprising a main barrier and an auxiliary barrier; and
A liquefied gas storage tank comprising a secondary heat insulating wall provided on the outside of the secondary barrier,
The first barrier is
A plurality of flat portions fixed to the upper surface of the first heat insulating wall, and a curved surface portion formed between the plurality of flat portions to form a curved surface toward the receiving space and including a horizontal curved portion and a vertical curved portion,
The curved part,
a pair of first curved portions connected to each of the adjacent flat portions and having a first radius of curvature r1;
a second curved portion forming an upper portion of the curved portion and having at least a second radius of curvature r2 greater than the first radius of curvature r1; and
A pair of third curved portions connecting each of the pair of first curved portions and the second curved portion and having at least a third radius of curvature r3 having a radius greater than the second radius of curvature r2,
The pair of third curved portions,
A liquefied gas storage tank, characterized in that the first center of curvature of any one third curved portion and the second center of curvature of the other third curved portion are shifted in the horizontal direction from the inside of the curved portion. According to claim 1,
The horizontal curved portion and the vertical curved portion are formed to intersect, and the horizontal curved portion and the vertical curved portion have the same height and width. delete According to claim 1, wherein the size of the third radius of curvature,
The liquefied gas storage tank, characterized in that it is larger than the sum of the size of the second radius of curvature and the size of the first radius of curvature. According to claim 1,
The ratio (W/H) of the width (W) to the height (H) of the curved portion is,
2.0 to 3.0 range (2.0 ≤ W/H ≤ 3.0),
Liquefied gas storage tank, characterized in that determined based on the thermal stress and pressure stress at a low temperature of the primary barrier. delete According to claim 1, wherein each of the pair of first curved portion,
A curved surface shape having the first radius of curvature between a first connection point connected to the flat portion and a second connection point connected to each of the pair of third curved portions,
The first connection point is the same position as the point where the curve of the first circle having the first radius of curvature from the center of curvature on the receiving space side and the vertical center line of the first circle intersect,
The second connection point is a liquefied gas storage tank, characterized in that it is located in the curved portion of the first circle within an angle of 30 degrees downward from a point where the first circle curve and the horizontal center line of the first circle intersect. According to claim 1, wherein the first barrier,
The liquefied gas storage tank, characterized in that it further comprises a projecting structure that is located within a predetermined distance from the intersection where the horizontal curved portion and the vertical curved portion intersect and protrudes toward the receiving space to be formed in the flat portion. The method of claim 8, wherein the protruding structure,
The liquefied gas storage tank, characterized in that it is smaller in size than the horizontal curved portion and the vertical curved portion, and has a convex circular or arc shape. The liquefied gas storage tank according to claim 1, wherein the first and second curvature centers of the pair of third curved portions are located above an imaginary plane formed by the flat portion. A ship characterized in that the liquefied gas storage tank of any one of claims 1, 2, 4, 5, and 7 to 10 is provided.

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