KR102375114B1 - Liquefied gas storage tank and vessel comprising the same - Google Patents

Abstract

The present invention relates to a liquefied gas storage tank and a ship including the same, wherein the liquefied gas storage tank of the present invention is a liquefied gas storage tank for storing cryogenic substances, and is made of a metal material that forms an accommodating space for accommodating the cryogenic substances. barrier; a first insulating wall in which a primary plywood and a primary insulating material are sequentially disposed to the outside of the primary barrier; a secondary barrier provided on the outside of the primary insulating wall; a secondary thermal insulation wall in which secondary thermal insulation materials and secondary plywood are sequentially stacked to the outside of the secondary barrier; and a leveling member installed between the second heat insulating wall and the hull, wherein the leveling member is made of a material having an elastic force, and the upper surface is flattened by being in close contact with the second heat insulating wall by the elastic force, and the lower surface is on the hull It is characterized in that it has a curved surface to fit the deformation of the hull in close contact.

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 such as LNG carriers that transport or store liquefied gas such as LNG at sea, LNG RV (Regasification Vessel), LNG FPSO (Floating, Production, Storage and Offloading), and LNG FSRU (Floating Storage and Regasification Unit), 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 intrusion of heat from the outside, and the natural vaporization rate (BOR), which is the vaporization rate of the boil-off gas through an adiabatic design, is Lowering the liquefied gas is a key technology in the design of the liquefied gas storage tank. 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.

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 make the thickness of the first insulating wall the same as or similar to that of the second insulating wall in the total thickness of the insulating wall, so that the mechanical An object of the present invention is to provide a liquefied gas storage tank capable of reducing the low temperature burden and the sloshing burden of the secondary barrier while maintaining the strength at a certain level, and a ship including the same.

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 insulation performance as well as reducing the man-hours.

A liquefied gas storage tank according to an aspect of the present invention is a liquefied gas storage tank for storing cryogenic substances, comprising: a primary barrier made of a metal material forming an accommodating space for accommodating the cryogenic substance; a first insulating wall in which a primary plywood and a primary insulating material are sequentially disposed to the outside of the primary barrier; a secondary barrier provided on the outside of the primary insulating wall; a secondary thermal insulation wall in which secondary thermal insulation materials and secondary plywood are sequentially stacked to the outside of the secondary barrier; and a leveling member installed between the second heat insulating wall and the hull, wherein the leveling member is made of a material having an elastic force, and the upper surface is flattened by being in close contact with the second heat insulating wall by the elastic force, and the lower surface is on the hull It is characterized in that it has a curved surface to fit the deformation of the hull in close contact.

Specifically, the leveling member, as a non-adhesive elastic insulating material, may be EPS (Expanded Polystyrene).

Specifically, a mastic and a leveling wedge may not be installed between the second insulating wall and the hull.

Specifically, it further comprises a fixing member for fixing the secondary heat insulating wall to the hull, the fixing member, the protrusion provided to protrude to the outside from both side lower portions of the unit panel of the adjacent secondary heat insulating wall; And it is fixedly installed on the hull so as to match the space between the unit panels of the neighboring secondary insulating wall, provided on each side of the unit panel of the neighboring secondary insulating wall, located between the two opposite projections By fixing the protrusion by tightening the bolt in the second insulation wall may be made of a stud bolt to be fixed to the hull.

Specifically, the lower surface of the protrusion may be at the same level as the lower surface of the secondary plywood, and one side may be fixedly installed on the side surface of the secondary plywood and part of the side surface of the secondary insulation material.

A 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 the thickness of the second insulation wall in the total thickness of the first insulation wall and the second insulation wall covering the connection insulation wall, 2 It is possible to maintain the mechanical strength of the barrier barrier at a certain level, as well as reduce the low-temperature burden and the sloshing burden 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 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 connection insulating wall provided in the space between the neighboring primary insulating walls constituting 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 according to the present invention apply a non-adhesive elastic insulating material as a leveling member of the secondary insulating wall between the secondary insulating wall and the hull, even if the existing mastic and leveling wedge are not used. It is possible to level the deformation part of the tank and to increase the thermal insulation performance of the tank.

In addition, the liquefied gas storage tank according to the present invention and a ship equipped therewith are provided with a protrusion provided to protrude outward from the lower side of the unit panel of the secondary insulating wall, and a cleat structure by a stud bolt fixed to the hull. By fixing the unit panel of the adjacent secondary insulating wall, it is possible to reduce the man-hour 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 thermal conductivity according to the materials used for the primary and secondary insulating materials 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.

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 gist 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 idea 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 elements, but the elements 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 a liquid state as well as LNG in a supercritical state, etc. 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 on 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 liquefied gas, a primary insulating wall (3) installed on the outside of the primary barrier (2), a primary insulating wall (3) installed outside the 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 of the primary insulating wall (3) and the 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, the transverse wall in the front-rear direction of the liquefied gas storage tank 1, the floor between the transverse walls, the vertical wall, and the 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 an obtuse-angled corner structure or a 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 primary 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 to have a wrinkle shape having 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, 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) has a gentle curve at the top, so it is easy to inspect for welding, and also flexibly responds to sloshing because the fluid hitting from the side flows directly. .

In addition, the primary barrier (2) of this embodiment, large corrugation (Large corrugation) and small corrugation (Small corrugation) without distinction, the horizontal and vertical wrinkle size in the entire area can be formed the same. 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 first thermal insulation wall 3 may have a structure in which the primary plywood 31 and the primary thermal insulation material 32 are sequentially stacked to the outside of the primary barrier 2, the primary plywood 31 It may correspond to the combined thickness of the thickness and the thickness of the primary insulating material (32). The first insulating wall 3 may be formed to a thickness of 160 mm to 250 mm, and may correspond to 201 mm 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 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 arranged adjacent to each other, and in this case, the connecting insulating wall 3a may be installed in a space portion between the neighboring primary thermal insulation walls 3 , that is, in a space portion 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 portion of the secondary heat insulating 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 for the primary insulation wall (3) constituting the unit element are laminated, in this specification, the first Note that the thermal wall 3 may encompass the connecting 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 connecting insulating wall 3a may have a structure in which a connecting plywood 31a and a connecting 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 connection insulation wall 3a is a structure inserted between the adjacent fixed insulation walls 3b constituting the unit element, it is weak in protecting the secondary barrier 4 under the connection insulation wall 3a from cryogenic temperatures. Have no choice but to. 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 the present 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 to 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 in a range of 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, also, 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 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 has 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 portion 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 at 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 second insulating wall 5 or the thickness of the connecting insulating material 32a and the secondary insulating material 51 of the primary insulating wall 3 were configured to be the same or similar, In this regard, it will be described with reference to FIGS. 4 to 20 .

4 (a) and (b) are secondary barriers ( 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, and the secondary insulating wall 5 in FIGS. 4 (a) and (b) 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, the self temperature is lowered, the amount of shrinkage itself increases, and there is a problem in that the risk of damage to the secondary barrier 4 increases by increasing the stress at low temperature. 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. 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 (a) of FIG. 4 , the connection insulating wall 3a is formed to be relatively thinner than the secondary insulating wall 5, so that 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 heat insulating wall 5 is secured as large as 2 The thickness of the heat-blocking wall 5 may be relatively thicker than that of the connection heat-insulating 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 entire 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 to (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 was 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 primary insulating wall 3 and the secondary 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 walls 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 first 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, in consideration of 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 second 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 (400 mm) 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 adjacent to each other, the secondary barrier (4) portion corresponding to the adjacent 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 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 connection insulating wall 3a and the secondary 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 (400mm) 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 adjacent to each other, the secondary barrier (4) portion corresponding to the adjacent secondary insulating 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 drawings showing the results of flow analysis while varying the thicknesses 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 connection 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 the state in which the unit elements are arranged adjacent to each other, the secondary barrier 4 corresponding to the adjacent 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 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 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 the center of the total thickness of the sum of the thicknesses of the insulating wall (3a) and the second 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 insulating 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 thermal contraction 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 becomes 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 connecting 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) 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 contraction 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 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 insulating wall 5 decreases (the thickness of the primary insulating 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 in (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 insulating wall 5, so that the secondary barrier 4 is the contractile force of the secondary insulating 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 is arranged to correspond to 40% or more in the combined thickness of the connecting insulating wall 3a and the secondary insulating wall 5. 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 connection insulating wall 3a and the primary insulating wall 3 is increased, the thickness of the secondary insulating wall 5 is relatively decreased. 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 thermal insulation wall 5 increases. have no choice but to

In addition, in the 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 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, but the greater the brittleness problem, 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 connection insulating wall 3a becomes thicker beyond 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 not only the low-temperature stress described above, but also the risk of cracking or destruction of the hull. 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 insulating wall 3a and the secondary insulating wall 5 are low-temperature stress and the 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 aspects of hull cracking. This is not exactly the same as the third case, but if 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 appropriately providing the thickness of the secondary insulating wall 4 to the hull By providing a gap between (7) and the secondary barrier (4), the secondary barrier (4) can reduce the burden on the structural stress transmitted from the hull (7), the second to fourth cases are appropriate This can be done by way of 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 of various configurations, 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 cloth (Aramid) material is applied to, 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 also 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 the present embodiment may be formed of various materials having a multi-layer structure in which the first member/aluminum foil (AF)/the 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 the first embodiment of the present invention. Some cross-sectional views for

5 to 20, when the thickness of the connecting insulating wall 3a or the first insulating wall 3 and the thickness of the secondary insulating wall 5 are the same or in a similar range, a more stable thermal 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-angle 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 when 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 angle corner structure, the secondary barrier 4 is moved to the hull 7 side compared to the existing thin primary insulating 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 the 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, it accounts for 15% to 35%.

In addition, in the obtuse-angled corner structure, the secondary barrier 4 moves toward the hull 7 side compared to the existing thin primary thermal insulation wall as the thickness of the primary thermal insulation wall 3 increases to 201 mm, and the radius of curvature decreases 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. The 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 insulating materials 32 and 32a and the secondary insulating material 51, and in consideration of the economical aspect, relatively close to cryogenic 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, in the liquefied gas storage tank 1 according to the second embodiment of the present invention, the 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 and 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 5 mm to 10 mm, and is made of plywood, high-density polyurethane foam (HD PUF), FRP (Fiber Reinforced Plastic), etc. to obtain the load distribution 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 is not only the lower part of the connecting insulating material 32a of the connecting insulating wall 3a, but also the lower part of 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. Here, of course, the leveling wedge may be selectively used.

In this embodiment, by applying the leveling member 8 as described above, unlike mastic, which is applied in several types according to the size of the existing gap, it can be constructed in a single size, and the mastic curing time is not required, so the working time can be shortened, and by applying an insulating material, it is possible to increase the thermal insulation power.

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 sides of the lower portion 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 the side and the secondary plywood 52 to a certain height from one side of the secondary plywood 52 of the secondary insulating wall 5 It 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 thermal insulation 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 bolt to secure the secondary insulating wall 5 to the hull. (7) can be fixed.

As described above, in this embodiment, the thickness of the primary thermal insulation walls 3 and 3a from the total thickness of the primary thermal insulation wall 3 and the secondary thermal insulation wall covering the connection thermal insulation wall 3a is divided into the secondary thermal insulation wall 5 and By configuring the same or similar, 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 sloshing burden of the secondary barrier (4). damage can be prevented.

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 neighboring 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 thermal insulation wall 5 between the secondary thermal insulation wall 5 and the hull 7, the existing mastic and leveling wedge are not used. Even if 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 at the lower side of the unit panel of the secondary heat insulating wall 5 and stud bolts 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 .

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. It will be clear that the transformation or improvement is possible.

All simple modifications or changes of the present invention fall within the scope of the present invention, and the specific protection scope of the present invention will become apparent from the appended claims.

1: Liquefied gas storage tank 2: Primary barrier
21: flat part 22: curved part
23: boundary part 3: primary thermal insulation wall
3b: fixed insulation wall 31: primary plywood
32: primary insulation material 3a: connection insulation wall
31a: connecting plywood 32a: connecting insulating 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: Second insulation material
52: secondary plywood 6: mastic
7: Hull 8: Leveling member
9: fixing member 91: protrusion
92: stud bolt

Claims (5)

A liquefied gas storage tank for storing a cryogenic material comprising a mastic for fixing the secondary insulating wall to the hull, and a leveling wedge for maintaining a gap between the secondary insulating wall and the hull,
a primary barrier made of a metal material to form an accommodating space for accommodating the cryogenic material;
a first insulating wall in which a primary plywood and a primary insulating material are sequentially disposed to the outside of the primary barrier;
a secondary barrier provided on the outside of the primary insulating wall;
the second insulating wall in which a secondary insulating material and a secondary plywood are sequentially disposed to the outside of the secondary barrier;
a leveling member installed between the second insulating wall and the hull; and
and a fixing member for fixing the second insulating wall to the hull,
The leveling member,
It is made of EPS (Expanded Polystyrene), which is a non-adhesive elastic insulation material with elasticity.
The upper surface is flattened by being in close contact with the second insulating wall by the elastic force, and the lower surface is in close contact with the hull and has a curved surface to fit the deformation of the hull,
It is formed in the form of a panel of a size corresponding to the size of the unit panel of the second insulation wall, and performs the mastic and the leveling wedge functions installed in the gap between the unit panel of the second insulation wall and the hull,
The upper surface is non-adhesive with the second insulating wall and the lower surface is non-adhesive with the hull to cope with the flow of the storage tank,
Since it is formed of an elastic material panel of a size corresponding to the unit panel size of the secondary thermal insulation wall, it is possible to level the deformed portion of the hull while supporting the entire secondary thermal insulation wall, and to increase the thermal insulation performance of the storage tank, ,
The fixing member is
It consists of a cleat structure including a protrusion and a stud bolt so as to fix the secondary heat insulating wall to the hull,
The protrusion is
formed from plywood,
It is provided to protrude to the outside from the lower side of both sides of the unit panel of the adjacent secondary heat insulating wall,
The lower surface forms the same level as the lower surface of the secondary plywood,
One side is fixedly installed over the side of the secondary plywood and some side of the secondary insulating material up to a certain height from the secondary plywood,
The stud bolt is
It is fixedly installed on the hull so as to match the space between the unit panels of the adjacent secondary insulating walls,
It is characterized in that the secondary heat insulating wall is fixed to the hull by fixing the protrusion by tightening the bolt in a state in which it is provided on each side of the unit panel of the adjacent secondary heat insulating wall and positioned between the two opposing protrusions. liquefied gas storage tank. delete delete delete delete

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