Liquefied gas storage tank and vessel comprising same

Abstract

This invention relates to liquefied gas storage tanks and ships including them. The liquefied gas storage tank of this invention can be constructed from a primary protective wall, a primary insulation wall, a secondary protective wall, and a secondary insulation wall to store cryogenic substances. The primary insulation wall may include: a connecting insulation wall, which is disposed in the space between adjacent fixed insulation walls when unit elements consisting of the secondary insulation wall, the secondary protective wall, and a fixed insulation wall that is part of the primary insulation wall are stacked adjacently. The liquefied gas storage tank may include: a first slit formed between the fixed insulation wall and the connecting insulation wall when the connecting insulation wall is inserted between adjacent fixed insulation walls; a second slit formed along the length and width directions of the fixed insulation wall; and a first filling insulation element filling the first slit.

Description

Technical Field

[0001] This invention relates to liquefied gas storage tanks and ships including them. Background Technology

[0002] In recent years, with technological development, liquefied gases such as liquefied natural gas (LNG) and liquefied petroleum gas (LPG) are being widely used to replace gasoline or diesel.

[0003] In addition, LNG carriers, LNG RVs (Regasification Vessels), LNG FPSOs (Floating, Production, Storage and Offloading) and LNG FSRUs (Floating Storage and Regasification Units) that transport or store liquefied gases such as LNG at sea are equipped with storage tanks (called "cargo tanks") for storing LNG in a cryogenic liquid state.

[0004] In addition, liquefied gas storage tanks may generate bloat gas (BOG) due to external heat intrusion. Reducing the bloat rate (BOR), the rate at which BOG is vaporized, through insulation design is a core technology in liquefied gas storage tank design. Furthermore, since liquefied gas storage tanks are exposed to various loads such as sloshing, it is necessary to ensure the mechanical strength of the insulation panels.

[0005] With this in mind, the thickness range of the primary and secondary insulation walls can be related to the mechanical strength of the liquefied gas storage tank. Therefore, research is actively underway to eliminate the cryogenic burden on the secondary insulation wall while maintaining its mechanical strength. Summary of the Invention

[0006] The technical problem to be solved

[0007] The present invention is proposed to solve the problems of the prior art as described above. The object of the present invention is to provide a liquefied gas storage tank and a ship including the same, by making the thickness of the primary insulation wall the same or similar to that of the secondary insulation wall in terms of the overall thickness of the insulation wall, thereby maintaining the mechanical strength of the secondary insulation wall at a predetermined level and reducing the low temperature load and sloshing load of the secondary insulation wall.

[0008] In addition, the present invention aims to provide a liquefied gas storage tank and a ship including the same, by making the thickness of the primary insulation wall the same or similar to that of the secondary insulation wall in terms of the overall thickness of the insulation wall, thereby reducing the cryogenic load and sloshing load of the secondary insulation wall to a extent that does not cause brittle fracture of the hull.

[0009] In addition, the present invention aims to provide a liquefied gas storage tank that can improve thermal insulation performance by improving the structure of the secondary protective wall, and a ship including the same.

[0010] In addition, the present invention aims to provide a liquefied gas storage tank and a ship including the same, which can improve thermal insulation performance and reduce the number of workers by improving the structure of the fixing member that fixes the secondary insulation wall to the hull.

[0011] Furthermore, the present invention aims to provide a liquefied gas storage tank and a ship comprising the same, which improves the stability of the primary insulation wall and reduces the cryogenic burden on the secondary insulation wall by optimizing the slits provided to cope with the contraction and expansion of the primary insulation wall formed on the secondary protective wall, and minimizing convection phenomena and heat penetration into the secondary protective wall generated through the slits.

[0012] Technical solutions to the problem

[0013] According to one aspect of the present invention, a liquefied gas storage tank can be constructed and used to store cryogenic substances, comprising a primary protective wall, a primary insulation wall, a secondary protective wall, and a secondary insulation wall. The primary insulation wall may include a connecting insulation wall, wherein the connecting insulation wall is disposed in the space between adjacent fixed insulation walls when unit elements consisting of the secondary insulation wall, the secondary protective wall, and a fixed insulation wall that is part of the primary insulation wall are stacked adjacently. The liquefied gas storage tank may include: a first slit, formed between the fixed insulation wall and the connecting insulation wall when the connecting insulation wall is inserted between adjacent fixed insulation walls; a second slit, having a plurality of slits formed along the length and width directions of the fixed insulation wall; and a first filling insulation element, filling the first slit.

[0014] Specifically, the first filling insulation member may be formed to completely fill the first slit, or the first filling insulation member may be formed to fill from the entrance of the first slit to a predetermined depth to form a space in the lower part of the first slit, or the first filling insulation member may be formed to fill the interior of the first slit in a multi-layer manner to form a plurality of spaces inside the first slit.

[0015] Specifically, when the first filling insulation is formed to fill the interior of the first slit in a multi-layered manner to form a plurality of spaces inside the first slit, the first filling insulation may include: a first upper filling insulation formed at the upper part of the first slit; a first middle filling insulation separated from the first upper filling insulation and formed at the middle of the first slit; and a first lower filling insulation separated from the first middle filling insulation and formed at the lower part of the first slit. The first upper filling insulation, the first middle filling insulation, and the first lower filling insulation may be formed of the same insulation or different insulations. The insulation may be glass wool, super lite, soft foam, or aerogel blanket.

[0016] Specifically, after the connecting heat insulation wall is inserted between the adjacent fixed heat insulation walls, the first filling heat insulation member can fill the first slit by inserting a clamp. Alternatively, the first filling heat insulation member can be attached to the two sides of the connecting heat insulation wall opposite to the sides of the fixed heat insulation wall by inserting the connecting heat insulation wall between the adjacent fixed heat insulation walls to fill the first slit.

[0017] Specifically, when the depth of the second slit is similar to the thickness of the fixed heat insulation wall, a second filling heat insulation member can be filled inside the second slit. The second filling heat insulation member can be formed to fill from the entrance of the second slit to a predetermined depth to form a space in the lower part of the second slit, or the second filling heat insulation member can be formed to fill the interior of the second slit in a multi-layer manner to form a plurality of spaces inside the second slit.

[0018] Specifically, when the second filling insulation is formed to fill the interior of the second slit in a multi-layered manner to form a plurality of spaces inside the second slit, the second filling insulation may include: a second upper filling insulation formed at the upper part of the second slit; a second middle filling insulation separated from the second upper filling insulation by a predetermined interval and formed in the middle of the second slit; and a second lower filling insulation separated from the second middle filling insulation by a predetermined interval and formed at the lower part of the second slit. The second upper filling insulation, the second middle filling insulation, and the second lower filling insulation may be formed of the same insulation or different insulation from each other. The insulation may be glass wool, super lite, soft foam, or aerogel blanket.

[0019] Specifically, it may include: a third slit, one or more of which are formed along the length direction of the connecting heat insulation wall, which, when the connecting heat insulation wall is inserted between the fixed heat insulation walls, is located on the same line as the second slit formed along the length direction; the second slit and the third slit may be formed to a depth corresponding to about half the thickness of the fixed heat insulation wall and the connecting heat insulation wall; the interior of the second slit and the third slit is not filled with a heat insulation element; the first heat insulation element may be formed to be at least longer than the depth of each of the second slit and the third slit; and the heat convection path formed by the first slit, the second slit and the third slit is discontinuous.

[0020] Specifically, the primary insulation wall and the secondary insulation wall may have the same or similar thickness.

[0021] Another embodiment of the present invention provides a liquefied gas storage tank that can be composed of a primary protective wall, a primary insulation wall, a secondary protective wall, and a secondary insulation wall to store cryogenic substances. The primary insulation wall may include: a connecting insulation wall, wherein the connecting insulation wall is disposed in the space between adjacent fixed insulation walls when unit elements composed of the secondary insulation wall, the secondary protective wall, and a fixed insulation wall that is part of the primary insulation wall are stacked adjacently. The liquefied gas storage tank may include: a first step portion formed on the front, rear, left, and right sides of the connecting insulation wall; a second step portion formed on the front, rear, left, and right sides of the fixed insulation wall; a first slit, formed by the first step portion and the second step portion when the connecting insulation wall is inserted between adjacent fixed insulation walls; and a first filling insulation member filling the first slit.

[0022] Specifically, the first step portion can be formed by making the front-back and left-right width of the upper part of the connecting heat insulation wall narrower than the front-back and left-right width of the lower part of the connecting heat insulation wall, and the second step portion can be formed by making the front-back and left-right width of the upper part of the fixed heat insulation wall narrower than the front-back and left-right width of the lower part of the fixed heat insulation wall. The first filling heat insulation member can fill the first slit, which is formed in the space between the upper part of the connecting heat insulation wall and the upper part of the fixed heat insulation wall by the lower part of the connecting heat insulation wall and the lower part of the fixed heat insulation wall being adjacent to each other.

[0023] Specifically, it may include: a plurality of second slits formed along the length and width directions of the fixed heat insulation wall; and a third slit formed along the length direction of the connecting heat insulation wall, wherein when the connecting heat insulation wall is inserted between the fixed heat insulation walls, it is located on the same line as the second slit formed along the length direction, the second slit and the third slit may be formed to a depth corresponding to about half the thickness of the fixed heat insulation wall and the connecting heat insulation wall, the interior of the second slit and the third slit is not filled with heat insulation material, the first slit filled with the first heat insulation material may be formed to be at least longer than the depth of each of the second slit and the third slit, and the heat convection path formed by the first slit, the second slit and the third slit is discontinuous.

[0024] Specifically, the primary insulation wall and the secondary insulation wall may have the same or similar thickness.

[0025] Technical effect

[0026] The liquefied gas storage tank of the present invention and the ship including the same thereof, by making the thickness of the primary insulation wall the same or similar to that of the secondary insulation wall in terms of the overall thickness of the primary insulation wall and the secondary insulation wall, can not only maintain the mechanical strength of the secondary insulation wall at a predetermined level, but also reduce the low temperature load and sway load of the secondary insulation wall, thereby preventing damage to the secondary insulation wall.

[0027] Furthermore, the liquefied gas storage tank of the present invention and the ship including it can prevent brittle fracture of the hull and reduce the low temperature load and sway load on the secondary protective wall by making the thickness of the primary heat insulation wall the same or similar to that of the secondary heat insulation wall in terms of the overall thickness of the primary heat insulation wall and the secondary heat insulation wall.

[0028] Furthermore, the liquefied gas storage tank of the present invention and the ship including the same can further improve the thermal insulation performance at the connection portion of the adjacent secondary thermal insulation walls of the unit element by providing an auxiliary thermal insulation plate on the bottom surface of the connecting thermal insulation wall disposed in the space between adjacent primary thermal insulation walls constituting the unit element.

[0029] In addition, the liquefied gas storage tank of the present invention and the ship including it can improve the thermal insulation performance by improving the structure of the secondary protective wall.

[0030] Furthermore, the liquefied gas storage tank of the present invention and the ship including it can adjust the level of the deformed parts of the hull and improve the heat insulation performance of the tank by applying the unattached elastic heat insulation element as a leveling component between the secondary heat insulation wall and the hull, even without using conventional adhesives and leveling wedges.

[0031] Furthermore, the liquefied gas storage tank of the present invention and the ship including it fix the adjacent secondary insulation wall unit panel by means of a protrusion provided on the lower side of the unit panel of the secondary insulation wall and a clamping structure of studs fixed to the hull, which can save labor compared with drilling holes in the secondary insulation wall and fixing the unit panel with studs.

[0032] Furthermore, the liquefied gas storage tank of the present invention and the ship including it improve the slit structure and make the filling insulation of the slits varied so as to optimize the slits provided to cope with the contraction and expansion of the primary insulation wall formed on the secondary protective wall, and minimize the convection phenomenon generated through the slits and the heat penetration into the secondary protective wall. This can improve the stability of the primary insulation wall formed based on the slits and reduce the low temperature burden on the secondary protective wall, thereby preventing damage to the primary insulation wall and the secondary protective wall. Attached Figure Description

[0033] Figure 1 This is a partial cross-sectional view of a liquefied gas storage tank used to illustrate a first embodiment of the present invention.

[0034] Figure 2 This is a partial perspective view illustrating the liquefied gas storage tank of the first embodiment of the present invention.

[0035] Figure 3 This is a diagram illustrating the primary protective wall of a liquefied gas storage tank according to a first embodiment of the present invention.

[0036] Figure 4 (a) and (b) are diagrams showing the tensile forces of the secondary protective wall as the thickness of the primary and secondary insulation walls varies.

[0037] Figures 5 to 8 This is a diagram illustrating the results of structural analysis performed by changing the thickness of the primary and secondary insulation walls of the first shell in order to derive the thickness of the primary and secondary insulation walls of the liquefied gas storage tank according to the first embodiment of the present invention.

[0038] Figures 9 to 12 This is a diagram showing the results of structural analysis performed by changing the thickness of the primary and secondary insulation walls of the second shell in order to derive the thickness of the primary and secondary insulation walls of the liquefied gas storage tank according to the first embodiment of the present invention.

[0039] Figures 13 to 16 This is a diagram showing the results of structural analysis performed by changing the thickness of the primary and secondary insulation walls of the third shell in order to derive the thickness of the primary and secondary insulation walls of the liquefied gas storage tank according to the first embodiment of the present invention.

[0040] Figures 17 to 20 This is a diagram showing the results of structural analysis performed by changing the thickness of the primary and secondary insulation walls of the fourth shell in order to derive the thickness of the primary and secondary insulation walls of the liquefied gas storage tank according to the first embodiment of the present invention.

[0041] Figure 21 It is a graph showing the low-temperature stress of the secondary protective wall and the probability of brittle failure of the hull, depending on the thickness variations of the primary and secondary insulation walls.

[0042] Figure 22 , Figure 23 as well as Figure 24 This is a diagram illustrating the various structures of the secondary protective wall of the liquefied gas storage tank according to the first embodiment of the present invention.

[0043] Figure 25 This is a partial cross-sectional view illustrating the right-angle corner structure of the liquefied gas storage tank according to the first embodiment of the present invention.

[0044] Figure 26 This is a partial cross-sectional view illustrating the obtuse-angle corner structure of the liquefied gas storage tank according to the first embodiment of the present invention.

[0045] Figure 27 This is a graph showing the thermal conductivity of the materials used in the primary and secondary insulation components of the liquefied gas storage tank according to the present invention.

[0046] Figure 28 This is a partial cross-sectional view of a liquefied gas storage tank used to illustrate a second embodiment of the present invention.

[0047] Figure 29 This is a partial perspective view illustrating the liquefied gas storage tank of the second embodiment of the present invention.

[0048] Figure 30 This is a partial cross-sectional view of a liquefied gas storage tank used to illustrate a third embodiment of the present invention.

[0049] Figure 31 This is an enlarged view of the main part of the liquefied gas storage tank according to the third embodiment of the present invention.

[0050] Figure 32 This is a partial cross-sectional view of a liquefied gas storage tank used to illustrate a fourth embodiment of the present invention.

[0051] Figure 33 This is a diagram illustrating a filling insulation element that fills a first slit forming a gap between a connecting insulation wall and a fixed insulation wall constituting a primary insulation wall, and a plurality of second slits disposed in the fixed insulation wall.

[0052] Figure 34 This is a diagram illustrating another embodiment of a filling insulation member that fills a first slit forming a gap between a connecting insulation wall and a fixed insulation wall constituting a primary insulation wall, and a plurality of second slits disposed in the fixed insulation wall.

[0053] Figure 35 This is a diagram illustrating another embodiment of a filling insulation member that fills a first slit forming a gap between a connecting insulation wall and a fixed insulation wall constituting a primary insulation wall, and a plurality of second slits disposed in the fixed insulation wall.

[0054] Figure 36 This is a partial cross-sectional view of a liquefied gas storage tank used to illustrate the fifth embodiment of the present invention.

[0055] Figure 37 It is along Figure 36 A cross-sectional view of the connecting insulation wall cut along line A-A'.

[0056] Figure 38 It is along Figure 36 A cross-sectional view of the unit elements consisting of a secondary insulation wall, a secondary protective wall, and a fixed insulation wall that forms the primary insulation wall, cut along line B-B'.

[0057] Figure 39 and Figure 40 This is a diagram illustrating a filling insulation component that fills the first slit forming a gap between the connecting insulation wall and the fixed insulation wall that constitute a primary insulation wall.

[0058] Figure 41 and Figure 42 This is a diagram showing the structural analysis results of a liquefied gas storage tank according to a fifth embodiment of the present invention.

[0059] Figures 43 to 46 This is a diagram illustrating the changes in convection path and temperature of the secondary protective wall in the liquefied gas storage tank of the fifth embodiment of the present invention and the liquefied gas storage tank of the comparative example, depending on the structure of the slit and the application of the filling insulation material filling the slit.

[0060] Figure 47 This is a graph showing the temperature of the secondary protective wall at the bottom of the slit, which changes depending on whether a heat-insulating filling element is provided in the liquefied gas storage tank of the fifth embodiment of the present invention and the liquefied gas storage tank of the comparative example.

[0061] Figure 48 This is a partial cross-sectional view of a liquefied gas storage tank used to illustrate the sixth embodiment of the present invention.

[0062] Figure 49 It is along Figure 48 A cross-sectional view of the connecting insulation wall cut along line A-A'.

[0063] Figure 50 It is along Figure 48 A cross-sectional view of the unit elements consisting of a secondary insulation wall, a secondary protective wall, and a fixed insulation wall that forms the primary insulation wall, cut along line B-B'.

[0064] Figure 51 This is an enlarged view showing the state in which the filling insulation element is filled in the first slit that forms a gap between the connecting insulation wall and the fixed insulation wall that constitute the primary insulation wall.

[0065] Figure 52 This is a perspective view illustrating the liquefied gas storage tank of the seventh embodiment of the present invention.

[0066] Figure 53 (a) to (c) respectively show Figure 52 Top view, side view, and sectional view of the unit elements consisting of a secondary insulation wall, a secondary protective wall, and a fixed insulation wall that constitutes a primary insulation wall.

[0067] Figure 54 (a) to (c) respectively show the components Figure 52 The top view, side view, and sectional view of the primary insulation wall connection.

[0068] Figure 55 (a) to (c) respectively show the components Figure 52 Top view, side view and sectional view of another embodiment of the primary insulation wall.

[0069] Figure 56 It constitutes Figure 52 A perspective view of the back of a connecting insulation wall, representing another embodiment of a primary insulation wall.

[0070] Figure 57 It is a cross-sectional view showing the alternating connection of the fixed insulation wall and the connecting insulation wall that constitute the primary insulation wall.

[0071] Figure 58 It is a cross-sectional view showing the continuous connection of a plurality of connected insulation walls that constitute a primary insulation wall. Detailed Implementation

[0072] The objectives, specific advantages, and novel features of the present invention will become clearer from the following detailed description and preferred embodiments associated with the accompanying drawings. In this specification, when labeling structural elements in the various drawings, it should be noted that identical structural elements are labeled as much as possible, even when shown in different drawings. Furthermore, in describing the invention, detailed descriptions of relevant prior art will be omitted if it is determined that such detailed descriptions might unnecessarily obscure the spirit of the invention.

[0073] Furthermore, it should be understood that the accompanying drawings are only provided to facilitate understanding of the embodiments disclosed in this specification. The technical concepts disclosed in this specification are not limited to the drawings, but rather cover all modifications, equivalents, and even substitutions included in the concept and technical scope of this invention.

[0074] Furthermore, terms such as "first," "second," etc., which include ordinal numbers, can be used to describe various structural elements, but these structural elements are not limited by these terms. The terms are used only for the purpose of distinguishing one structural element from others.

[0075] In this specification, liquefied gas may be used to mean all gaseous fuels that are typically stored in a liquid state, such as LNG or LPG, ethylene, and ammonia. For ease of explanation, gases that are heated or pressurized instead of being in a liquid state may also be described as liquefied gas. This also applies to evaporating gases. Furthermore, for ease of explanation, LNG may be used to mean both liquid NG (Natural Gas) and supercritical LNG, and evaporating gas may be used to mean both gaseous evaporating gas and liquefied evaporating gas.

[0076] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0077] Figure 1 This is a partial cross-sectional view of a liquefied gas storage tank used to illustrate the first embodiment of the present invention. Figure 2 This is a partial perspective view illustrating the liquefied gas storage tank of the first embodiment of the present invention. Figure 3 This is a diagram illustrating the primary protective wall of a liquefied gas storage tank according to a first embodiment of the present invention.

[0078] like Figure 1 and Figure 2 As shown, the liquefied gas storage tank 1 of the first embodiment of the present invention can be installed on a ship to store liquefied gases such as LNG, which are extremely low temperature (approximately -160°C to -170°C) substances.

[0079] Although not illustrated, it should be understood that the ship equipped with the liquefied gas storage tank 1 described below includes not only merchant ships that transport cargo from place of origin to destination, but also marine structures that float at a predetermined location at sea and perform specific operations. Furthermore, it should be noted that the liquefied gas storage tank 1 in this invention also includes tanks of any shape for storing liquefied gases.

[0080] The liquefied gas storage tank 1 may include: a primary protective wall 2 in contact with the liquefied gas, a primary heat insulation wall 3 disposed outside the primary protective wall 2, a secondary protective wall 4 disposed outside the primary heat insulation wall 3, and a secondary heat insulation wall 5 disposed outside the secondary protective wall 4. The liquefied gas storage tank 1 may be supported on the hull 7 by means of an adhesive 6 disposed between the secondary heat insulation wall 5 and the hull 7.

[0081] In the liquefied gas storage tank 1, to optimize insulation performance and storage capacity, it may be necessary to optimize the thickness of the primary insulation wall 3 and the secondary insulation wall 5. For example, when polyurethane foam is used as the main material for both the primary insulation wall 3 and the secondary insulation wall 5, the total thickness of the primary insulation wall 3 and the secondary insulation wall 5 can be in the range of 250 mm to 500 mm. This will be discussed further in [the following text is incomplete and requires further context]. Figures 4 to 20 The explanation is provided below.

[0082] The aforementioned liquefied gas storage tank 1 may include planar and corner structures. For example, the transverse walls in the front-to-back direction, the bottom surface between the transverse walls, the longitudinal walls, and the roof of the liquefied gas storage tank 1 can be equivalent to a planar structure. Additionally, for example, the structure where the transverse walls, bottom surface, longitudinal walls, and roof of the liquefied gas storage tank 1 meet can be equivalent to a corner structure. The corner structure may include an obtuse-angle corner structure or a right-angle corner structure. When the thickness of the primary insulation wall 3 or the secondary insulation wall 5 changes, the obtuse-angle corner structure or the right-angle corner structure may change accordingly. Figure 25 and Figure 26 The explanation is provided below.

[0083] Reference Figure 1 and Figure 2 The primary protective wall 2 can form a containment space for liquefied gas, which is an extremely low temperature substance, and can be made of metal. For example, the metal material can be stainless steel, but it is not limited to this. The primary protective wall 2, together with the secondary protective wall 4, can prevent liquefied gas from leaking to the outside.

[0084] The primary protective wall 2 can be configured to be fixedly attached to the upper part of the primary insulation wall 3 by means of anchor bolts (not shown), and to be in direct contact with the liquefied gas, which is a cryogenic substance, stored in the liquefied gas storage tank 1.

[0085] Reference Figure 3The primary protective wall 2 can be divided into a flat portion 21 that contacts the top surface of the primary insulation wall 3, a curved portion 22 for relieving contraction or expansion stress caused by temperature, and a boundary portion 23 between the flat portion 21 and the curved portion 22. For example, it can be formed from a corrugated membrane sheet made of stainless steel with a thickness of 1.0 to 1.5 mm, preferably stainless steel with a thickness of 1.0 to 1.2 mm. That is, the primary protective wall can be formed in a corrugated shape.

[0086] The primary protective wall 2 can be formed into a pleated shape having a first radius of curvature R1 and a second radius of curvature R2. That is, the primary protective wall 2 in this embodiment can be formed to have two types of radii of curvature R1 and R2, with the first radius of curvature R1 formed on the boundary 23 between the flat portion 21 and the curved portion 22, and the second radius of curvature R2 formed on the curved portion 22. For example, the first radius of curvature R1 can be formed to be smaller than the second radius of curvature R2. In the primary protective wall 2 having radii of curvature R1 and R2, since a gentle curve is formed on its upper part, it is easy to inspect the welds, and fluid impacted from the side can flow away directly, thereby flexibly responding to shaking.

[0087] Furthermore, in this embodiment, the horizontal and vertical corrugations in the entire area of ​​the primary protective wall 2 can be formed with the same size, without distinguishing between large corrugations and small corrugations. That is, since the horizontal and vertical corrugations in the entire primary protective wall 2 are the same size, the primary protective wall can be easily manufactured.

[0088] Reference Figure 1 The primary insulation wall 3 can be designed to block heat intrusion from the outside and withstand impacts from the outside or from internal liquefied gas sloshing, and can be set between the primary protective wall 2 and the secondary protective wall 4.

[0089] The primary insulation wall 3 may have a structure in which a primary clamping plate 31 and a primary insulation element 32 are stacked sequentially on the outside of the primary protective wall 2, and its thickness may correspond to the sum of the thickness of the primary clamping plate 31 and the thickness of the primary insulation element 32. The primary insulation wall 3 may be formed with a thickness of 160 mm to 250 mm.

[0090] The primary clamping plate 31 can be set between the primary protective wall 2 and the primary heat insulation component 32.

[0091] The primary clamping plate 31 can be formed to a thickness of 6.5mm to 15mm.

[0092] The primary insulation element 32 can be formed of a material with excellent thermal insulation performance and excellent mechanical strength, so as to block heat intrusion from the outside and withstand impacts from the outside or impacts caused by internal liquefied gas sloshing.

[0093] The primary insulation element 32 can be formed of polyurethane foam between the primary sandwich panel 31 and the secondary protective wall 4, and its thickness can correspond to a thickness range of 150 mm to 240 mm.

[0094] Reference Figure 1 A unit element can be constructed by stacking a portion of a primary insulation wall 3, a secondary protective wall 4, and a secondary insulation wall 5. The portion of the primary insulation wall 3 constituting the unit element can be defined as a fixed insulation wall 3b, the width of which can be smaller than the width of the secondary insulation wall 5 included in the unit element. Furthermore, the fixed insulation wall 3b, the secondary protective wall 4, and the secondary insulation wall 5 can be configured in a pre-fixed state, but are not limited to this; they can also be separately configured within the liquefied gas storage tank 1. Therefore, a portion of the secondary protective wall 4 can be exposed to both sides of the primary insulation wall 3. Multiple unit elements can be arranged adjacently, and in this case, a connecting insulation wall 3a can be provided in the space between adjacent primary insulation walls 3, i.e., the space where the secondary protective wall 4 is exposed.

[0095] The secondary protective wall 4 can be divided into a main protective wall 41 and an auxiliary protective wall 42. The main protective wall 41 is located above the secondary insulation wall 5 in the unit element, and the auxiliary protective wall 42 is located between the exposed main protective wall 41 and the connecting insulation wall 3a. In this case, the auxiliary protective wall 42 is configured to connect the main protective walls 41 of a plurality of adjacent unit elements to each other. That is, a plurality of adjacent unit elements can be terminated by the auxiliary protective wall 42 stacked on the main protective wall 41 and the connecting insulation wall 3a.

[0096] Reference Figure 2 The following describes the stacking structure of the portion provided with the connecting heat insulation wall 3a. The connecting heat insulation wall 3a can be configured to be stacked in a manner similar to or the same as that described in the primary heat insulation wall 3 constituting the unit element, with the connecting clamp 31a and connecting heat insulation member 32a stacked. In this specification, it should be understood that the primary heat insulation wall 3 may include the connecting heat insulation wall 3a and the fixed heat insulation wall 3b.

[0097] Figure 2 It shows Figure 1 The cross-sectional structure of the A-A' surface allows the connecting insulation wall 3a to have a stacked structure of connecting clamping plate 31a and connecting insulation element 32a. The thickness of the connecting insulation wall 3a can correspond to the sum of the thickness of the connecting clamping plate 31a and the thickness of the connecting insulation element 32a.

[0098] The connecting clamp 31a can be formed to have a thickness of 6.5 mm to 15 mm.

[0099] The connecting insulation element 32a can be formed of polyurethane foam between the connecting clamp 31a and the auxiliary protective wall 42 of the secondary protective wall 4, and its thickness can correspond to a thickness range of 150mm to 240mm.

[0100] As described above, the primary insulation member 32 of the primary insulation wall 3 and the connecting insulation member 32a connecting the primary insulation wall 3a can have the same thickness. However, in the case of the connecting insulation member 32a connecting the primary insulation wall 3a, an auxiliary protective wall 42 is stacked below it in addition to the main protective wall 41 of the secondary protective wall 4. Therefore, the connecting insulation member 32a connecting the primary insulation wall 3a can have a thickness that is smaller than the thickness of the primary insulation member 32 of the primary insulation wall 3 and is correspondingly smaller than the thickness of the auxiliary protective wall 42.

[0101] The aforementioned connecting insulation wall 3a is configured to seal, together with the auxiliary protective wall 42, the space between adjacent secondary insulation walls 5 when multiple unit elements are arranged adjacently, and to block heat intrusion from the outside.

[0102] However, since the connecting insulation wall 3a has a structure that inserts between adjacent fixed insulation walls 3b constituting the unit element, it is inherently vulnerable in protecting the secondary protective wall 4 below the connecting insulation wall 3a from extremely low temperatures. Therefore, the secondary protective wall 4 below the connecting insulation wall 3a, where the main protective wall 41 and the auxiliary protective wall 42 overlap, is highly likely to experience problems. Therefore, the following explanation will focus on the connecting insulation wall 3a.

[0103] The secondary protective wall 4 can be set between the primary heat insulation wall 3 (including the heat insulation wall 3a) and the secondary heat insulation wall 5, and together with the primary protective wall 2, it can prevent liquefied gas from leaking to the outside.

[0104] The secondary protective wall 4 at the lower end of the fixed heat insulation wall 3b may include a main protective wall 41 as a single protective wall, and the secondary protective wall 4 connecting the lower end of the heat insulation wall 3a may include a main protective wall 41 that connects the unit elements to each other and an auxiliary protective wall 42 provided on the secondary heat insulation wall 5 that constitutes the unit element.

[0105] The main protective wall 41 can be set on the secondary insulation wall 5 that constitutes the unit element, and has a thickness of 0.6 mm to 1.0 mm. The main protective walls 41 adjacent to each other can achieve airtightness by stacking auxiliary protective walls 42.

[0106] The auxiliary protective wall 42 is a structure that connects multiple unit elements to each other. It can be formed with a thickness of 0.6 mm to 1.0 mm and is stacked on the main protective wall 41.

[0107] On the other hand, refer to Figure 1 and Figure 2 The secondary insulation wall 5 can be designed to block external heat intrusion together with the fixed insulation wall 3b and the connecting insulation wall 3a, and to withstand external impacts or impacts caused by internal liquefied gas sloshing. Furthermore, the secondary insulation wall 5 can be disposed between the secondary protective wall 4 and the hull 7, and can include a secondary insulation element 51 and a secondary clamping plate 52.

[0108] The secondary insulation wall 5 can have a structure in which secondary insulation components 51 and secondary clamping plates 52 are stacked sequentially on the outside of the secondary protective wall 4. The overall thickness of the secondary insulation components 51 and the secondary clamping plates 52 can be 150 mm to 240 mm.

[0109] The secondary insulation component 51 can be formed of a material with excellent thermal insulation performance and excellent mechanical strength, so as to block heat intrusion from the outside and withstand impacts from the outside or impacts caused by internal liquefied gas sloshing.

[0110] The secondary insulation component 51 can be formed of polyurethane foam between the secondary protective wall 4 and the secondary clamping plate 52, and can be formed to a thickness of 140mm to 230mm.

[0111] The secondary clamping plate 52 can be disposed between the secondary insulation member 51 and the hull 7. For example, the secondary insulation member 51 can be configured to contact the secondary clamping plate 52. The secondary clamping plate 52 can be formed to have a thickness of 6.5 mm to 25 mm.

[0112] As described above, the liquefied gas storage tank 1 of this embodiment can be configured such that the primary insulation wall 3 has a thickness of 66% to 166% of that of the secondary insulation wall 5, and the connecting insulation wall 3a included in the primary insulation wall 3 has a thickness of 67% to 167% of that of the secondary insulation wall 5, so that the connecting insulation wall 3a has the same or similar thickness as the secondary insulation wall 5. In relation to this structure, the connecting insulation member 32a of the connecting insulation wall 3a has a thickness of 90% to 110% of that of the secondary insulation member 51, so that the connecting insulation member 32a of the connecting insulation wall 3a has the same or similar thickness as the secondary insulation member 51. In this embodiment, it should be noted that as long as the connecting insulation wall 3a is included, even if the fixed insulation wall 3b constituting the unit element is not specifically mentioned, in relation to the secondary insulation wall 5, the fixed insulation wall 3b is also the same or similar to the connecting insulation wall 3a.

[0113] When the connecting insulation wall 3a and the secondary insulation wall 5, or the connecting insulation element 32a and the secondary insulation element 51 of the connecting insulation wall 3a, are formed with such a thickness ratio, the upper limit of the low-temperature stress of the secondary protective wall 4 can be below 50 MPa at the lower part of the connecting insulation wall 3a. Specifically, the low-temperature stress value of the secondary protective wall 4 at the lower part of the connecting insulation wall 3a can be between 40 MPa and 50 MPa. These values ​​are obtained based on the results of the structural analysis described later.

[0114] In this embodiment, the thickness of the connecting heat insulation wall 3a and the secondary heat insulation wall 5, or the thickness of the connecting heat insulation member 32a and the secondary heat insulation member 51 of the primary heat insulation wall 3, are configured to be the same or similar. Reference will be made to this. Figures 4 to 20 To illustrate.

[0115] Figure 4 (a) and (b) are diagrams illustrating the tensile force of the secondary protective wall 4 at the lower part of the connecting insulation wall 3a, which is included in the primary insulation wall 3, according to the thickness variation of the connecting insulation wall 3a and the secondary insulation wall 5. Assuming... Figure 4 In (a) and (b), the overall thickness of the connecting insulation wall 3a, secondary protective wall 4, secondary insulation wall 5, etc. is the same.

[0116] On the other hand, the secondary protective wall 4 and the secondary insulation wall 5 differ in their shrinkage amount depending on the exposed temperature. In the case of the secondary protective wall 4 and the secondary insulation wall 5, the thinner the connecting insulation wall 3a, the more susceptible it is to the effects of the extremely low temperature liquefied gas. In addition, in this case, the shrinkage amount increases as the temperature decreases, thus increasing the risk of damage to the secondary protective wall 4 due to increased stress at low temperatures. This problem occurs more frequently in the auxiliary protective wall 42, which connects the main protective walls 41 of adjacent unit elements to each other using adhesives or the like at the lower part of the connecting insulation wall 3a. This is because, at the lower part of the connecting insulation wall 3a, the two ends of the auxiliary protective wall 42 are connected to the main protective walls 41 of each unit element. As the secondary insulation walls 5 of the unit element shrink, the two ends of the auxiliary protective wall 42 may deform and move away from or closer to each other.

[0117] Reference Figure 4 (a) shows a case where the connecting heat insulation wall 3a is formed relatively thinner than the secondary heat insulation wall 5, and the height of the secondary protective wall 4 is located above the center of the overall thickness with respect to the thickness direction. In this case, in order to reduce the mechanical stress exerted on the secondary protective wall 4 when the hull deforms structurally due to the six degrees of freedom motion of the hull 7, the thickness of the secondary heat insulation wall 5 can be made relatively thicker than that of the connecting heat insulation wall 3a by ensuring a larger thickness.

[0118] Reference Figure 4(b) shows a case where the thicknesses of the connecting insulation wall 3a and the secondary insulation wall 5 are similar, and the height of the secondary protective wall 4 is located in the central region of the overall thickness, with reference to the thickness direction. This central region can correspond to a range of 40% to 60% of the overall thickness. In this case, with... Figure 4 Compared to (a), the shrinkage itself is reduced, thus reducing the stress at low temperatures. Additionally, compared to... Figure 4 Compared to (a), the risk of damage to the secondary protective wall is relatively lower.

[0119] In this invention, a liquefied gas storage tank 1 is derived that can maintain the mechanical strength of the secondary insulation wall 5 at a predetermined level and can reduce the low-temperature load and sloshing load of the secondary protective wall 4. Hereinafter, it will be described with reference to the following description. Figures 5 to 20 To understand.

[0120] Figures 5 to 20 In the liquefied gas storage tank 1 of the above embodiment, in order to export the thickness of the primary insulation wall 3 and the secondary insulation wall 5, which include the connecting insulation wall 3a, by pressing the first shell ( Figures 5 to 8 ), second shell ( Figures 9 to 12 ), third shell ( Figures 13 to 16 ), fourth shell ( Figures 17 to 20 The diagram shows the results of structural analysis by changing the thickness of the connecting insulation wall 3a and the secondary insulation wall 5. In this embodiment, although the thickness of the connecting insulation wall 3a is the main focus of the explanation, it should be understood that the thickness of the primary insulation wall 3 is also the same as or similar to that of the connecting insulation wall 3a.

[0121] The analysis conditions for each shell are as follows.

[0122] First, the overall thickness of the connecting insulation wall 3a and the secondary insulation wall 5 of the first to fourth shells in the analysis model is the same, 400 mm.

[0123] Second, by changing the thickness of the connecting insulation wall 3a and the secondary insulation wall 5, only the position of the secondary protective wall 4 was changed.

[0124] Third, considering the same linear temperature distribution conditions, the temperature at position 2 of the primary protective wall is set to -163°C, which is the temperature of the liquefied gas, and the temperature at position 7 of the hull is set to 20°C, which is the normal temperature.

[0125] Fourth, the minimum and maximum values ​​of fixed stress are represented by colors to indicate different stress levels. For example, red indicates the maximum stress value, and bluer colors indicate the smaller the stress value.

[0126] Fifth, the thickness ratio is the proportion of the thickness of the connecting insulation wall 3a in the overall thickness (400mm).

[0127] The structures of the first to fourth shells, which served as the analysis model, were analyzed under the analysis conditions described above.

[0128] Figures 5 to 8 These are figures showing the results of structural analysis performed on the liquefied gas storage tank according to the first embodiment of the present invention, in order to derive the thickness of the connecting insulation wall 3a and the secondary insulation wall 5 included in the primary insulation wall 3, by changing the thickness of the connecting insulation wall 3a and the secondary insulation wall 5 of the first shell.

[0129] like Figure 5 As shown, the first housing is a housing with a thickness of 100 mm for the connecting heat insulation wall 3a and a thickness of 300 mm for the secondary heat insulation wall 5. That is, in the first housing, the thickness of the connecting heat insulation wall 3a accounts for 0.25 of the total thickness (400 mm) of the connecting heat insulation wall 3a and the secondary heat insulation wall 5, and the secondary protective wall 4 is located near the center of the total thickness of the combined thickness of the connecting heat insulation wall 3a and the secondary heat insulation wall 5, close to the side of the primary protective wall 2, which serves as the upper end.

[0130] In the case of such a first shell, such as Figures 6 to 8 As shown in the structural analysis results, under the condition of multiple unit elements being configured adjacently, the secondary protective wall 4 part corresponding to the adjacent secondary insulation wall 5 is in the red system, and the calculated stress value is 70.12 MPa.

[0131] In the case of the first shell, the reason for the stress generated in the secondary protective wall 4 can be found through... Figure 4 This is to confirm. That is, as the thickness of the connecting insulation wall 3a decreases, the secondary protective wall 4 is more affected by the temperature of the liquefied gas.

[0132] Figures 9 to 12 These are figures showing the results of structural analysis performed on the liquefied gas storage tank according to the first embodiment of the present invention, in order to derive the thickness of the connecting insulation wall 3a and the secondary insulation wall 5 included in the primary insulation wall 3, by changing the thickness of the connecting insulation wall 3a and the secondary insulation wall 5 of the second shell.

[0133] like Figure 9 As shown, the second shell is a shell with a thickness of 160 mm for the connecting heat insulation wall 3a and a thickness of 240 mm for the secondary heat insulation wall 5. That is, in the second shell, the thickness of the connecting heat insulation wall 3a accounts for 0.4 of the total thickness (400 mm) of the connecting heat insulation wall 3a and the secondary heat insulation wall 5, and the secondary protective wall 4 is located slightly off-center from the center of the total thickness of the sum of the thicknesses of the connecting heat insulation wall 3a and the secondary heat insulation wall 5 towards the primary protective wall 2.

[0134] In the case of such a second shell, such as Figures 10 to 12As shown in the structural analysis results, under the condition of multiple unit elements being configured adjacently, the secondary protective wall 4 part corresponding to the adjacent secondary insulation wall 5 is yellow, and the calculated stress value is 55.09 MPa.

[0135] Figures 13 to 16 These are figures showing the results of structural analysis performed on the liquefied gas storage tank according to the first embodiment of the present invention, in order to derive the thickness of the connecting heat insulation wall 3a and the secondary heat insulation wall 5 included in the primary heat insulation wall 3, by changing the thickness of the connecting heat insulation wall 3a and the secondary heat insulation wall 5 of the third shell.

[0136] like Figure 13 As shown, the third shell is formed with the same or similar thickness as the connecting insulation wall 3a and the secondary insulation wall 5. That is, in the third shell, the thickness of the connecting insulation wall 3a accounts for approximately 0.5 of the total thickness (400 mm) of the connecting insulation wall 3a and the secondary insulation wall 5, and the secondary protective wall 4 is located adjacent to the center of the total thickness of the combined thickness of the connecting insulation wall 3a and the secondary insulation wall 5.

[0137] In the case of such a third shell, such as Figures 14 to 16 As shown in the structural analysis results, under the condition of multiple unit elements being configured adjacently, the secondary protective wall 4 part corresponding to the adjacent secondary insulation wall 5 is a light sky blue system, and the calculated stress value is 47.63 MPa.

[0138] Figures 17 to 20 These are figures showing the results of structural analysis performed on the liquefied gas storage tank according to the first embodiment of the present invention, in order to derive the thickness of the connecting insulation wall 3a and the secondary insulation wall 5 included in the primary insulation wall 3, by changing the thickness of the connecting insulation wall 3a and the secondary insulation wall 5 of the fourth shell.

[0139] like Figure 17 As shown, the fourth shell is a shell with a thickness of 240 mm for the connecting heat insulation wall 3a and a thickness of 160 mm for the secondary heat insulation wall 5. That is, in the fourth shell, the thickness of the connecting heat insulation wall 3a accounts for 0.6 of the total thickness (400 mm) of the connecting heat insulation wall 3a and the secondary heat insulation wall 5, and the secondary protective wall 4 is located below the center of the total thickness of the combined thickness of the connecting heat insulation wall 3a and the secondary heat insulation wall 5.

[0140] In the case of such a fourth shell, such as Figures 18 to 20 As shown in the structural analysis results, under the condition of multiple unit elements being configured adjacently, the secondary protective wall 4 part corresponding to the adjacent secondary insulation wall 5 is a sky blue system, and the calculated stress value is 41.21 MPa.

[0141] As described above, the structural analysis results of the first to fourth shells show that the secondary protective wall 4, which connects to the lower part of the heat insulation wall 3a, tends to exhibit a decrease in low-temperature stress caused by thermal contraction as it moves away from the primary protective wall 2. (Refer to...) Figure 21 Please provide an explanation.

[0142] Figure 21 This is a graph showing the relationship between the low-temperature stress of the secondary protective wall and the probability of brittle failure of the hull, depending on the thickness variations of the primary and secondary insulating walls.

[0143] like Figure 21 The graph shown indicates that the stress values ​​of the first to fourth shells and the secondary protective wall 4 connected to the lower part of the heat insulation wall 3a decrease at low temperatures due to thermal contraction as they move away from the primary protective wall 2. That is, it can be seen that the temperature of the secondary protective wall 4 connected to the lower part of the heat insulation wall 3a increases relatively as it moves away from the primary protective wall 2 compared to when it is closer, thus reducing contraction and stress. In this embodiment, the description focuses on the secondary protective wall 4 connected to the lower part of the heat insulation wall 3a, but it is obvious that the stress of the secondary protective wall 4 below the fixed heat insulation wall 3b, which constitutes the unit element, also decreases as it moves away from the primary protective wall 2. The secondary protective wall 4 connected to the lower part of the heat insulation wall 3a is a stacked state of the main protective wall 41 and the auxiliary protective wall 42, while the secondary protective wall 4 below the primary heat insulation wall 3 is composed only of the main protective wall 41.

[0144] In the liquefied gas storage tank 1 of this embodiment derived as described above, the temperature of the secondary protective wall 4 is increased by increasing the thickness of the connecting insulation wall 3a to the overall thickness of the combined thickness of the connecting insulation wall 3a and the secondary insulation wall 5 (reducing the influence of the cold and heat of the cryogenic liquid gas). This reduces the shrinkage of the secondary protective wall 4 caused by cold and heat, and also reduces the stress caused by cold and heat, thereby preventing damage to the secondary protective wall 4 caused by cold and heat. This principle also applies to the secondary protective wall 4, which is defined as including the lower part of the primary insulation wall 3, connecting insulation wall 3a.

[0145] Furthermore, in the secondary protective wall 4, as the thickness of the connecting insulation wall 3a and the fixed insulation wall 3b increases (while the thickness of the secondary insulation wall 5 decreases relatively), the swaying load and fluid dynamic load transmitted to the secondary protective wall 4 decrease, and the stress caused by swaying decreases, thereby preventing damage caused by swaying. Additionally, as the thickness of the secondary insulation wall 5 decreases (while the thickness of the primary insulation wall 3 increases relatively), the flatness of the secondary protective wall 4 can be easily adjusted.

[0146] In addition, as the thickness of the connecting insulation wall 3a and the fixed insulation wall 3b increases, the thickness of the secondary insulation wall 5 decreases relatively and moves relatively away from the primary protective wall 2. Therefore, the shrinkage force of the secondary insulation wall 5 caused by heat and cold also decreases. As the shrinkage force of the secondary insulation wall 5 decreases, the tensile force of the secondary protective wall 4 decreases, thereby preventing the secondary protective wall 4 from being damaged by the shrinkage force of the secondary insulation wall 5.

[0147] Considering the low-temperature stress of such a secondary protective wall 4, in this invention, the connecting insulation wall 3a can be configured such that its thickness corresponds to more than 40% of the combined thickness of the connecting insulation wall 3a and the secondary insulation wall 5. Preferably, the liquefied gas storage tank 1 of this invention can be configured as a second to a fourth shell, i.e., the connecting insulation wall 3a corresponds to 40% to 60% of the combined thickness of the connecting insulation wall 3a and the secondary insulation wall 5. More preferably, the liquefied gas storage tank 1 of this invention can be configured as a third shell, i.e., the connecting insulation wall 3a corresponds to 47% to 53% of the combined thickness of the connecting insulation wall 3a and the secondary insulation wall 5.

[0148] However, if the thickness of the connecting heat insulation wall 3a and the primary heat insulation wall 3 is increased, the thickness of the secondary heat insulation wall 5 will be relatively reduced. Therefore, the secondary heat insulation wall 5 will inevitably be vulnerable to the mechanical stress applied when the hull 7 deforms structurally due to the six degrees of freedom motion of the hull 7. As a result, the degree of mechanical stress transmitted to the secondary protective wall 4 through the secondary heat insulation wall 5 will inevitably increase.

[0149] Furthermore, when carrying liquefied gas, an emergency condition such as the rupture of the primary protective wall 2 may occur. In this situation, the primary protective wall 2 can no longer prevent the leakage of liquefied gas, and therefore the liquefied gas may come into contact with the secondary protective wall 4. Additionally, if the secondary protective wall 4 comes into contact with the extremely low-temperature liquefied gas, the temperature of the hull will decrease, potentially increasing the probability of brittle fracture. Moreover, as the temperature drops, the material strength relative to the hull increases, leading to brittleness issues and thus potentially increasing the probability of brittle fracture. Brittle fracture can correspond to sudden failure with almost no plastic deformation, and can also be understood as brittle cracking.

[0150] In this regard, refer to Figure 21 In emergency situations, as the secondary protective wall 4, which comes into contact with the extremely low-temperature liquefied gas, gradually approaches the hull from the first to the fourth hull, the probability of brittle fracture increases. That is, in... Figure 21In this process, the probability of brittle failure of the hull increases from the first hull to the fourth hull, that is, as the thickness of the connecting heat insulation wall increases compared to the thickness of the secondary heat insulation wall 5. Furthermore, when the thickness of the connecting heat insulation wall 3a of the fourth hull further increases, the probability of brittle failure approaches 1, and the hull may crack or split.

[0151] Therefore, the insulation system of the liquefied gas storage tank 1 needs to be configured not only to consider the aforementioned cryogenic stress, but also to consider the risk of hull cracking or damage. In this invention, when both cryogenic stress and hull cracking are taken into account, a suitable configuration may be a second to a fourth shell located in the central region of the overall thickness of the secondary protective wall 4, which is the sum of the thicknesses of the insulation wall 3a and the secondary insulation wall 5. Preferably, a third shell is suitable in terms of the mechanical aspects of cryogenic stress and hull cracking.

[0152] Therefore, in this invention, the low-temperature stress of the secondary protective wall 4 is reduced by sufficiently ensuring the thickness of the connecting insulation wall 3a and the primary insulation wall 3, and the spacing between the hull 7 and the secondary protective wall 4 is set by appropriately setting the thickness of the secondary insulation wall 4, thereby reducing the burden of structural stress transmitted from the hull 7 on the secondary protective wall 4. The second to fourth shells are suitable embodiments where this reduces the burden of structural stress transmitted from the hull 7 on the secondary protective wall 4. Furthermore, when considering both low-temperature stress and mechanical strength, the third shell is a preferred embodiment.

[0153] On the other hand, the secondary protective wall 4 can be constructed from various materials, which will be discussed in [the following text is incomplete and requires further context]. Figures 22 to 24 The explanation is provided below.

[0154] Figure 22 , Figure 23 as well as Figure 24 These are diagrams illustrating various structures of the secondary protective wall of the liquefied gas storage tank according to the first embodiment of the present invention.

[0155] like Figure 22 As shown, the secondary protective wall 4 can be formed from a first material of a three-layer structure consisting of glass fabric GC / aluminum foil AF / glass-aramid fabric GAC stacked together.

[0156] Glass-aramid fabrics (GACs) use aramid materials in glass cloth and are manufactured by mixing one aramid fiber with every two glass fibers.

[0157] Such a primary material can be applied to the auxiliary protective wall 42 of the secondary protective wall 4, and is not limited thereto; it can also be applied to the main protective wall 41 of the secondary protective wall 4.

[0158] like Figure 23 As shown, the secondary protective wall 4 can be formed from a second material with a five-layer structure of stacked glass fabric GC / aluminum foil AF / glass fabric GC / aluminum foil AF / glass fabric GC.

[0159] Such a second material can be applied to the main protective wall 41 of the secondary protective wall 4, and is not limited thereto. Of course, it can also be applied to the auxiliary protective wall 42 of the secondary protective wall 4.

[0160] like Figure 24 As shown, the secondary protective wall 4 uses an inorganic basalt fabric extracted from basalt, which can be formed by a third material with a three-layer structure of basalt fabric BC / aluminum foil AF / basalt fabric BC stacked.

[0161] Such a third material can be applied to the main protective wall 41 of the secondary protective wall 4, and is not limited to it. Of course, it can also be applied to the auxiliary protective wall 42 of the secondary protective wall 4.

[0162] like Figures 22 to 24 As described above, the secondary protective wall 4 in this embodiment can be formed from a variety of materials in a multi-layer structure of a first component / aluminum foil AF / second component stacked together. In this case, at least one of the first and second components can be glass fabric GC, glass-aramid fabric GAC, basalt fabric BC, or glass fabric GC / aluminum foil AF / glass fabric GC.

[0163] In addition, the various materials used in the secondary protective wall 4 can also be used in various combinations in the main protective wall 41 and the auxiliary protective wall 42 of the secondary protective wall 4.

[0164] Figure 25 This is a partial cross-sectional view illustrating the right-angle corner structure of the liquefied gas storage tank according to the first embodiment of the present invention. Figure 26 This is a partial cross-sectional view illustrating the obtuse-angle corner structure of the liquefied gas storage tank according to the first embodiment of the present invention.

[0165] In the above Figures 5 to 20 It was found that when the thickness of the connecting insulation wall 3a or the primary insulation wall 3 and the thickness of the secondary insulation wall 5 are formed within the same or similar range, a more stable insulation system will be achieved. For example, the same or similar range can mean that the position of the secondary protective wall 4 is located at 40% to 60% of the total thickness of the combined thickness of the connecting insulation wall 3a or the primary insulation wall 3 and the secondary insulation wall 5. The structure described above can also be applied in the same way. Figure 25 The right-angle corner structure of the liquefied gas storage tank 1 shown and Figure 26 The obtuse-angle corner structure of the liquefied gas storage tank 1 shown.

[0166] However, in the right-angle and obtuse-angle corner structures of the liquefied gas storage tank 1, the secondary protective wall 4 can only be formed as a curve. When formed as a curve, it is more vulnerable to loads from the surrounding environment compared to a straight section. This embodiment can alleviate the stress caused by such loads. In addition, this embodiment can easily absorb hull deformation.

[0167] Reference Figure 25 In the right-angle corner structure, as the thickness of the primary insulation wall 3 becomes thicker than that of the first shell and the second shell, the radius of curvature of the secondary protective wall 4 accounts for more than 25% of the thickness of the primary insulation wall 3, for example, 25% to 50%.

[0168] Furthermore, in a right-angle corner structure, as the primary insulation wall 3 becomes thicker than the first and second hulls, the secondary protective wall 4 will move towards the hull 7 compared to the previously thinner primary insulation wall. In this case, the radius of curvature increases, and with this increase, the length L1 of the un-glued portion (the scab part not glued) of the secondary protective wall 4 and the secondary insulation wall 5 also increases. In a right-angle corner structure, this means increased flexibility of the secondary protective wall 4, allowing it to more easily absorb deformations from the surrounding area, such as hull deformation, and reducing low-temperature stress. For example, the length L1 of the un-glued portion can be between 100mm and 200mm.

[0169] Reference Figure 26 In the obtuse corner structure, as the thickness of the primary insulation wall 3 becomes thicker than that of the first shell and the second shell, the radius of curvature of the secondary protective wall 4 accounts for more than 15% of the thickness of the primary insulation wall 3, for example, 15% to 35%.

[0170] Furthermore, in the obtuse-angle corner structure, as the primary insulation wall 3 becomes thicker than the first and second hulls, the secondary protective wall 4 moves towards the hull 7 and its radius of curvature increases compared to the previously thinner primary insulation wall. In this case, as the radius of curvature of the secondary protective wall 4 increases, the length L2 of the un-glued portion (the scab part not glued) of the secondary protective wall 4 to the secondary insulation wall 5 also increases. In the obtuse-angle corner structure, this means increased flexibility of the secondary protective wall 4, allowing it to more easily absorb deformations of the surrounding area, such as hull deformation, and reducing low-temperature stress. For example, the length L2 of the un-glued portion can be between 50 mm and 90 mm.

[0171] As described above, in the secondary protective wall 4 of the right-angle corner structure and obtuse-angle corner structure of the present invention, compared with the conventional right-angle corner structure and obtuse-angle corner structure of the primary heat insulation wall formed by a relatively thin thickness, the stress applied to the secondary protective wall at low temperatures can be reduced. In addition, since the unattached portion is increased, the absorption of hull deformation is also easier.

[0172] Figure 27 It is a graph showing the thermal conductivity of the materials used for the primary and secondary insulation components of a liquefied gas storage tank.

[0173] In the liquefied gas storage tank 1 of the above-described embodiment of the present invention, it is described that the primary insulation members 32, 32a connecting the insulation wall 3a and the primary insulation wall 3, and the secondary insulation member 51 of the secondary insulation wall 5 are all formed of polyurethane foam of the same material, but different polyurethane foams can be selectively used depending on the situation.

[0174] Specifically, rigid polyurethane foam (RPUF) is made by mixing polyol, isocyanate, and blowing agent, and can use HFC-245fa or CO2 as the blowing agent. Compared to CO2, HFC-245fa may be relatively expensive.

[0175] In this embodiment, the primary insulation components 32 and 32a are formed using rigid polyurethane foam with CO2 as a blowing agent, and the secondary insulation component 51 is formed using rigid polyurethane foam with HFC-245fa as a blowing agent.

[0176] Reference Figure 27 The thermal conductivity characteristics of blowing agents HFC-245fa and CO2 were observed by curve graphs. Compared with blowing agent CO2, the thermal conductivity value of blowing agent HFC-245fa is lower at room temperature, but the closer to the extremely low temperature, the more similar or identical the values ​​are.

[0177] That is, the thermal conductivity values ​​of the foaming agent HFC-245fa and the foaming agent CO2, with -80℃ as the base point, show the same or similar values ​​at temperatures below this point, while at temperatures above this point, the value of the foaming agent HFC-245fa is lower than that of the foaming agent CO2.

[0178] Therefore, in this embodiment, the relatively expensive blowing agent HFC-245fa is not used in both the primary insulation components 32, 32a and the secondary insulation component 51. Considering economic factors, the primary insulation components 32, 32a, which are relatively close to the extremely low temperature, can be formed of rigid polyurethane foam using CO2 as the blowing agent, and the secondary insulation component 51 can be formed of rigid polyurethane foam using HFC-245fa as the blowing agent.

[0179] Figure 28 This is a partial cross-sectional view of a liquefied gas storage tank used to illustrate a second embodiment of the present invention. Figure 29 This is a partial perspective view illustrating the liquefied gas storage tank of the second embodiment of the present invention.

[0180] like Figures 28 to 29 As shown, the liquefied gas storage tank 1 of the second embodiment of the present invention may include: a primary protective wall 2 in contact with the liquefied gas inside, a primary heat insulation wall 3 and a connecting heat insulation wall 3a disposed on the outside of the primary protective wall 2, a secondary protective wall 4 disposed on the outside of the primary heat insulation wall 3 and the connecting heat insulation wall 3a, and a secondary heat insulation wall 5 disposed on the outside of the secondary protective wall 4 and fixed to the hull 7. Compared with the first embodiment described above, the structure of the connecting heat insulation wall 3a is different, while the other structures are the same or similar. Therefore, only the different parts will be described below to avoid repetition.

[0181] In this embodiment, the structure connecting the heat insulation wall 3a may be different from that in the first embodiment described above.

[0182] Specifically, compared to the first embodiment described above, the connecting heat insulation wall 3a may further include an auxiliary heat insulation plate 33.

[0183] That is, the connecting insulation wall 3a can be formed as a structure in which the connecting clamp 31a, the connecting insulation component 32a, and the auxiliary insulation plate 33 are stacked.

[0184] The auxiliary insulation panel 33 can have a thickness of 5mm to 10mm and is made of plywood, high-density polyurethane foam (HD PUF), FRP (fiber-reinforced plastic), etc., thereby achieving the load-distribution effect of the secondary protective wall 4. Alternatively, the auxiliary insulation panel 33 can be made of VIP (vacuum insulation panel), low-density polyurethane foam (LD PUF), etc., which have excellent thermal insulation properties, thereby compensating for the thermal insulation vulnerability of the part that forms the connection to the insulation wall 3a.

[0185] The connecting insulation member 32a connecting the insulation wall 3a and the primary insulation member 32 constituting the unit element of the fixed insulation wall 3b can have the same thickness. However, in the case of the connecting insulation wall 3a, in addition to the main protective wall 41 of the secondary protective wall 4, an auxiliary protective wall 42 is stacked at its lower part, and an auxiliary insulation plate 33 is also included. Therefore, the thickness of the connecting insulation member 32a connecting the insulation wall 3a can be smaller than the primary insulation member 32 of the primary insulation wall 3 by an amount corresponding to the thickness of the auxiliary protective wall 42 and the auxiliary insulation plate 33.

[0186] Of course, the aforementioned auxiliary heat insulation plate 33 can not only be installed at the lower part of the connecting heat insulation member 32a that connects to the heat insulation wall 3a, but also at the lower part of the primary heat insulation member 32 that constitutes the unit element of the primary heat insulation wall 3.

[0187] Figure 30 This is a partial cross-sectional view of a liquefied gas storage tank used to illustrate a third embodiment of the present invention. Figure 31 This is an enlarged view of the main part of the liquefied gas storage tank according to the third embodiment of the present invention.

[0188] like Figure 30 and Figure 31 As shown, the liquefied gas storage tank 1 of the third embodiment of the present invention may include: a primary protective wall 2 in contact with the liquefied gas inside, a primary heat insulation wall 3 and a connecting heat insulation wall 3a disposed outside the primary protective wall 2, a secondary protective wall 4 disposed outside the primary heat insulation wall 3 and the connecting heat insulation wall 3a, a secondary heat insulation wall 5 disposed outside the secondary protective wall 4 and fixed to the hull 7, a leveling member 8 disposed between the secondary heat insulation wall 5 and the hull 7, and a fixing member 9 fixing the secondary heat insulation wall 5 to the hull 7. Compared with the first embodiment described above, the leveling member 8 and the fixing member 9 are different, while other structures are the same or similar. Therefore, hereafter, only the leveling member 8 and the fixing member 9, which are structural elements different from the first embodiment, and the parts changed therefrom, will be described to avoid repetition.

[0189] The leveling component 8 can be set between the secondary insulation wall 5 and the hull 7.

[0190] The leveling component 8 can adjust the level of the deformed parts of the hull 7. It is an unattached elastic insulation component that can improve the heat insulation performance of the tank and support the secondary heat insulation wall 5. It can be EPS (Expanded Polystyrene) or similar materials.

[0191] In such a leveling member 8, the top surface, which is pressed against the secondary insulation wall 5 by elastic force, is formed flat, while the bottom surface, which is pressed against the hull 7, can have a curved surface corresponding to the deformation of the hull 7. The deformation of the hull 7 may occur, for example, during the welding of the hull 7 blocks together.

[0192] That is, even without using conventional adhesives and leveling wedges, leveling component 8 can adjust the level of deformed parts of the hull. Of course, leveling wedges can be used selectively here.

[0193] In this embodiment, by applying the leveling member 8 as described above, unlike the conventional method of applying adhesive in various forms according to the size of the gap, it is possible to apply the adhesive in a single size without requiring an adhesive curing time. Therefore, the operation time can be shortened and the thermal insulation capacity can be improved by applying the insulation component.

[0194] The fixing member 9 can be composed of a clamping structure including a protrusion 91 and a stud 92, so as to fix the secondary heat insulation wall 5 to the hull 7.

[0195] The protrusion 91 can be provided to protrude outward from the lower part of both sides of the unit panel of the secondary insulation wall 5, and can be formed by a clamping plate.

[0196] One side of the protrusion 91 can be fixedly installed across the side of the secondary clamping plate 52 of the secondary insulation wall 5 and a part of the side of the secondary insulation member 51 from the secondary clamping plate 52 to a predetermined height. The bottom surface of the protrusion 91 is at the same level as the bottom surface of the secondary clamping plate 52.

[0197] The width of the protrusion 91 can be such that when multiple unit panels constituting the secondary heat insulation wall 5 are configured, studs 92 can be inserted between the protrusions 91 facing each other.

[0198] Stud 92 can be fixed to the hull 7.

[0199] The stud 92 can be fixed to the hull 7 in such a way that it corresponds to the space between the multiple unit panels of the secondary heat insulation wall 5 when multiple unit panels constituting the secondary heat insulation wall 5 are configured.

[0200] With the stud 92 positioned between two opposing protrusions 91 located on the side of the unit panel of the adjacent secondary insulation wall 5, the secondary insulation wall 5 can be fixed to the hull 7 by tightening the bolts.

[0201] Figure 32 This is a partial cross-sectional view of a liquefied gas storage tank used to illustrate the fourth embodiment of the present invention. Figure 33 This is a diagram illustrating a filling insulation component that fills a first slit forming a gap between a connecting insulation wall and a fixed insulation wall constituting a primary insulation wall, and a plurality of second slits disposed in the fixed insulation wall. Figure 34 This is a diagram illustrating another embodiment of a filling insulation member that fills a first slit forming a gap between a connecting insulation wall and a fixed insulation wall constituting a primary insulation wall, and a plurality of second slits disposed in the fixed insulation wall. Figure 35 This is a diagram illustrating another embodiment of a filling insulation member that fills a first slit forming a gap between a connecting insulation wall and a fixed insulation wall constituting a primary insulation wall, and a plurality of second slits disposed in the fixed insulation wall.

[0202] like Figures 32 to 35As shown, the liquefied gas storage tank 1 of the fourth embodiment of the present invention may include: a primary protective wall 2 in contact with the liquefied gas inside; a primary heat insulation wall 3 disposed outside the primary protective wall 2 and composed of a connecting heat insulation wall 3a and a fixed heat insulation wall 3b; a secondary protective wall 4 disposed outside the primary heat insulation wall 3; and a secondary heat insulation wall 5 disposed outside the secondary protective wall 4 and fixed to the hull 7. Compared with the first embodiment described above, the difference is that a first slit SL1 that fills the gap between the connecting heat insulation wall 3a and the fixed heat insulation wall 3b is filled, and a plurality of second slits SL2 are provided in the fixed heat insulation wall 3b. Other structures are the same or similar, so the following description focuses on the different parts to avoid repetition.

[0203] As mentioned above, the primary insulation wall 3 and the secondary insulation wall 5 in this embodiment can have the same or similar thickness.

[0204] The primary insulation wall 3 can be composed of a connecting insulation wall 3a and a fixed insulation wall 3b.

[0205] The connecting insulation wall 3a can be inserted between adjacent fixed insulation walls 3b when multiple unit elements including the fixed insulation wall 3b are arranged adjacently to seal the space formed between adjacent secondary insulation walls 5. At this time, a gap can be formed between the connecting insulation wall 3a and the fixed insulation wall 3b.

[0206] The first slit SL1 is a gap formed between the connecting insulation wall 3a and the fixed insulation wall 3b, and its depth can correspond to the thickness of the primary insulation wall 3.

[0207] In addition, in this embodiment, a plurality of second slits SL2 spaced apart from each other can be formed in the fixed heat insulation wall 3b to accommodate the contraction and expansion of the fixed heat insulation wall 3b.

[0208] The depth of the second slit SL2 can be formed to be similar to the thickness of the fixed insulation wall 3b, so as to maximize the mitigation of temperature-induced shrinkage or expansion stresses applied to the fixed insulation wall 3b. For example, when the thickness of the fixed insulation wall 3b is 200 mm, the depth of the second slit SL2 can be 185 mm to 195 mm, and is not limited thereto.

[0209] The first slit SL1 and the second slit SL2 mentioned above alleviate the contraction or expansion stress caused by temperature, thereby preventing damage to the primary insulation wall 3. However, they also act as convection paths, which may increase the low-temperature load on the secondary protective wall 4.

[0210] Therefore, in this embodiment, the first slit SL1 is completely or partially filled by the first filling insulation member GW1, and the second slit SL2 is partially filled by the second filling insulation member GW2, thereby preventing damage to the fixed insulation wall 3b caused by shrinkage and expansion, and reducing the low-temperature burden on the secondary protective wall 4, which will be explained in detail below.

[0211] The first filling insulation element GW1 and the second filling insulation element GW2 can be inserted into the first slit SL1 and the second slit SL2 using a clamp.

[0212] like Figures 33 to 35 As shown, the first filling insulation element GW1 can be formed to completely fill the first slit SL1 (see reference). Figure 33 Alternatively, it can be configured to fill from the inlet of the first slit SL1 to a predetermined depth to form a space at the lower part of the first slit SL1 (see reference). Figure 34 Alternatively, it can be configured to fill the interior of the first slit SL1 in a multi-layered manner, thereby forming a plurality of spaces within the first slit SL1 (see reference). Figure 35 ).

[0213] In addition, such as Figures 33 to 35 As shown, the second filling insulation element GW2 can be formed to fill from the inlet of the second slit SL2 to a predetermined depth, so as to form a space at the lower part of the second slit SL2 (see reference). Figure 33 and Figure 34 Alternatively, it can be configured to fill the interior of the second slit SL2 in a multi-layered manner, thereby creating a plurality of spaces within the second slit SL2 (see reference). Figure 35 ).

[0214] In the above, the first filling insulation member GW1 filling the first slit SL1 and the second filling insulation member GW2 filling the second slit SL2 can be formed to have (+) tolerance, so that the space can be completely sealed when filled in the space of the first slit SL1 and the second slit SL2, and thus can absorb contraction and expansion.

[0215] Reference Figure 33 The first filling insulation GW1 can be formed to completely fill the first slit SL1, and the second filling insulation GW2 can be formed to fill from the entrance of the second slit SL2 to a predetermined depth to form a space at the bottom of the second slit SL2.

[0216] The first filling insulation element GW1 and the second filling insulation element GW2 can be formed of glass wool, but are not limited thereto.

[0217] In the above description, the first filling insulation element GW1 is formed to completely fill the first slit SL1, thereby improving the thermal insulation performance of the connection portion connecting the thermal insulation wall 3a and the fixed thermal insulation wall 3b. The second filling insulation element GW2 is formed to create a space in the lower part of the second slit SL2, thereby not only improving the thermal insulation performance of the fixed thermal insulation wall 3b using the second filling insulation element GW2, but also absorbing the contraction and expansion of the fixed thermal insulation wall 3b in the space portion of the second slit SL2.

[0218] Reference Figure 34 The first filling insulation member GW1 can be formed to fill from the inlet of the first slit SL1 to a predetermined depth to form a space at the bottom of the first slit SL1, and the second filling insulation member GW2 can be formed to fill from the inlet of the second slit SL2 to a predetermined depth to form a space at the bottom of the second slit SL2.

[0219] The first filling insulation element GW1 and the second filling insulation element GW2 can be formed of glass wool, but are not limited thereto.

[0220] In the above, the first filling insulation member GW1 is formed to create a space in the lower part of the first slit SL1, thereby not only improving the thermal insulation performance of the connection between the thermal insulation wall 3a and the fixed thermal insulation wall 3b, but also absorbing the contraction and expansion of the connection between the thermal insulation wall 3a and the fixed thermal insulation wall 3b in the space portion of the first slit SL1. The second filling insulation member GW2 is formed to create a space in the lower part of the second slit SL2, thereby not only improving the thermal insulation performance of the fixed thermal insulation wall 3b, but also absorbing the contraction and expansion of the fixed thermal insulation wall 3b in the space portion of the second slit SL2.

[0221] Reference Figure 35 The first filling insulation member GW1 can be formed to fill the first slit SL1 in a multi-layer manner to form a plurality of spaces therein, and the second filling insulation member GW2 can be formed to fill the second slit SL2 in a multi-layer manner to form a plurality of spaces therein.

[0222] The first filling insulation GW1 may include: a first upper filling insulation GW1-1, formed at the upper part of the first slit SL1; a first intermediate filling insulation GW1-2, separated from the first upper filling insulation GW1-1 by a predetermined interval and formed in the middle of the first slit SL1; and a first lower filling insulation GW1-3, separated from the first intermediate filling insulation GW1-2 by a predetermined interval and formed at the lower part of the first slit SL1.

[0223] The first upper filling insulation component GW1-1, the first middle filling insulation component GW1-2, and the first lower filling insulation component GW1-3 can be formed as the same insulation component or as different insulation components. In this case, glass wool, super lite, soft foam, aerogel blanket, etc. can be used as insulation components.

[0224] The second filling insulation member GW2 may include: a second upper filling insulation member GW2-1, formed at the upper part of the second slit SL2; a second middle filling insulation member GW2-2, separated from the second upper filling insulation member GW2-1 by a predetermined interval and formed in the middle of the second slit SL2; and a second lower filling insulation member GW2-3, separated from the second middle filling insulation member GW2-2 by a predetermined interval and formed at the lower part of the second slit SL2.

[0225] The second upper filling insulation component GW2-1, the second middle filling insulation component GW2-2, and the second lower filling insulation component GW2-3 can be formed as the same insulation component or as different insulation components. In this case, glass wool, super lite, soft foam, aerogel blanket, etc. can be used as insulation components.

[0226] In the above, the first filling insulation element GW1 is formed in multiple layers to create a plurality of spaces inside the first slit SL1. This not only improves the insulation performance of the connection between the connecting insulation wall 3a and the fixed insulation wall 3b using the multiple layers of the first filling insulation elements GW1-1, GW1-2, and GW1-3, but also absorbs the contraction and expansion of the connecting insulation wall 3a and the fixed insulation wall 3b in the plurality of spaces of the first slit SL1. The second filling insulation element GW2 is formed to create a plurality of spaces inside the second slit SL2. This not only improves the insulation performance of the fixed insulation wall 3b using the multiple layers of the second filling insulation elements GW2-1, GW2-2, and GW2-3, but also absorbs the contraction and expansion of the fixed insulation wall 3b in the plurality of spaces of the second slit SL2.

[0227] Figure 36 This is a partial cross-sectional view illustrating the liquefied gas storage tank of the fifth embodiment of the present invention. Figure 37 It is along Figure 36 A cross-sectional view of the connecting insulation wall cut along line A-A'. Figure 38 It is along Figure 36 A cross-sectional view of a unit element consisting of a secondary insulation wall, a secondary protective wall, and a fixed insulation wall that forms the primary insulation wall, cut along line B-B'. Figure 39 and Figure 40A diagram illustrating a filling insulation component that fills the first slit forming the gap between the connecting insulation wall and the fixed insulation wall that constitute a primary insulation wall. Figure 41 and Figure 42 This is a diagram showing the structural analysis results of the liquefied gas storage tank according to the fifth embodiment of the present invention. Figures 43 to 46 This is a diagram used to compare and illustrate the changes in convection path and temperature of the secondary protective wall in the liquefied gas storage tank of the fifth embodiment described above and the liquefied gas storage tank of the comparative example, depending on the structure of the slit and whether or not a filling insulation element is applied to fill the slit. Figure 47 This is a graph showing the temperature of the secondary protective wall at the bottom of the slit, which varies depending on the presence or absence of a filling insulation member in the liquefied gas storage tank of the fifth embodiment of the present invention and the liquefied gas storage tank of the comparative example.

[0228] like Figures 36 to 40 As shown, the liquefied gas storage tank 1 of the fifth embodiment of the present invention may include: a primary protective wall 2 in contact with the liquefied gas inside; a primary heat insulation wall 3 disposed outside the primary protective wall 2 and composed of a connecting heat insulation wall 3a and a fixed heat insulation wall 3b; a secondary protective wall 4 disposed outside the primary heat insulation wall 3; and a secondary heat insulation wall 5 disposed outside the secondary protective wall 4 and fixed to the hull 7. Compared with the aforementioned fourth embodiment, the first filling heat insulation member GW1 that fills the first slit SL1 that forms the gap between the connecting heat insulation wall 3a and the fixed heat insulation wall 3b and the plurality of second slits SL2 disposed on the fixed heat insulation wall 3b are different. Other structures are the same or similar. Therefore, the following description focuses on the different parts to avoid repetition.

[0229] As mentioned above, the primary insulation wall 3 and the secondary insulation wall 5 in this embodiment can have the same or similar thickness.

[0230] The primary insulation wall 3 can be composed of a connecting insulation wall 3a and a fixed insulation wall 3b. In this case, the connecting insulation wall 3a can be inserted between adjacent fixed insulation walls 3b when multiple unit elements including the fixed insulation wall 3b are arranged adjacently, to seal the space formed between adjacent secondary insulation walls 5. At this time, a gap can be formed between the connecting insulation wall 3a and the fixed insulation wall 3b.

[0231] The first slit SL1 is a gap formed between the connecting insulation wall 3a and the fixed insulation wall 3b, and its depth can correspond to the thickness of the primary insulation wall 3.

[0232] Furthermore, in this embodiment, a plurality of second slits SL2 spaced at predetermined intervals can be formed on the fixed heat insulation wall 3b to accommodate the contraction and expansion of the fixed heat insulation wall 3b. The second slits SL2 can be formed not only along the length of the fixed heat insulation wall 3b, but also... Figure 38As shown, more than one can be formed in the width direction.

[0233] Furthermore, in this embodiment, one or more third slits SL3 can be formed in the connecting heat insulation wall 3a to accommodate the contraction and expansion of the connecting heat insulation wall 3a. Figure 37 As shown, the third slit SL3 can be formed more than once in the relatively long length direction, but not in the relatively narrow width direction. When the connecting heat insulation wall 3a is inserted between the fixed heat insulation walls 3b, the third slit SL3 formed in the length direction can be located on the same line as the second slit SL2 formed in the length direction.

[0234] In the above description, the second slit SL2 can be formed to a depth corresponding to approximately half the thickness of the fixed insulation wall 3b, and its interior is not filled with insulation material. This mitigates the temperature-induced shrinkage or expansion stress applied to the fixed insulation wall 3b and ensures insulation performance. For example, when the thickness of the fixed insulation wall 3b is 200 mm, the depth of the second slit SL2 can be approximately 90 mm, but is not limited to this; it can also be formed in the range of 100 mm to 50 mm. The third slit SL3 can be formed similarly or identically to the second slit SL2.

[0235] In the case where the first slit SL1, the second slit SL2, and the third slit SL3 are not filled with any heat insulation material, such as Figure 41 The structural analysis results shown confirm that, compared to the fixed insulation wall 3b with a shallower second slit SL2, the insulation performance of the fixed insulation wall 3b near the deeper first slit SL1 and the connecting insulation wall 3a is reduced. This is because more convection occurs through the deeper first slit SL1.

[0236] Therefore, in this embodiment, the first filling insulation element GW1 is used to partially fill the first slit SL1, such as... Figure 42 The structural analysis results shown confirm that the first insulating filler GW1 prevents heat convection, thus enabling the fixed insulating wall 3b and connecting insulating wall 3a near the deeper first slit SL1 to exhibit similar insulation performance to the fixed insulating wall 3b with the shallower second slit SL2. In other words, it can be confirmed that when the first insulating filler GW1 is filled in the first slit SL1, the low-temperature transfer depth of all parts is flattened.

[0237] In this embodiment, the first filling insulation GW1 filling the first slit SL1 is formed to be at least longer than the depth of the second slit SL2 or the third slit SL3 having a depth corresponding to about half the thickness of the fixed insulation wall 3b or the connecting insulation wall 3a, in order to improve the heat convection phenomenon caused by the slit.

[0238] Specifically, when the convection path formed by the space portion of the first slit SL1 partially filled with the first filling insulation member GW1 is connected to the convection path formed by the space portion of the second slit SL2 fixed in the insulation wall 3b and the convection path formed by the space portion of the third slit SL3 connecting the insulation wall 3a, the heat convection phenomenon increases. Therefore, in order to prevent the heat convection phenomenon, it is necessary to use the first filling insulation member GW1 to block the path.

[0239] For example, if the depth of the second slit SL2 and the third slit SL3 is 90 mm, and the first filling insulation GW1 is formed to a length of 80 mm from the entrance of the first slit SL1, a connection path of 10 mm will be formed. Therefore, the length of the first filling insulation GW1 must be at least 90 mm to block the connection path.

[0240] In addition, such as Figure 40 As shown, in this embodiment, the first filling insulation member GW1 can be attached to the two sides of the connecting insulation wall 3a opposite to the side of the fixed insulation wall 3b using the bonding member 10.

[0241] In the prior art, the connecting heat insulation wall 3a is placed between adjacent fixed heat insulation walls 3b, and then the first filling heat insulation member GW1 is inserted and installed using a clamp. However, in this embodiment, the connecting heat insulation wall 3a, with the first filling heat insulation member GW1 attached to both sides, can be directly inserted and installed between adjacent fixed heat insulation walls 3b, thereby saving installation labor. At this time, before the connecting heat insulation wall 3a is inserted and installed between adjacent fixed heat insulation walls 3b, the first filling heat insulation member GW1 attached to the fixed heat insulation wall 3b is kept in a compressed state (a state of reduced volume), and after installation, it is in a state of decompression (a state of increased volume), thereby completely covering the first slit SL1.

[0242] In the above description, although it is stated that the first filling insulation element GW1 of this embodiment partially fills the first slit SL1, it is of course possible that it can also be filled in conjunction with the reference. Figure 33 and Figure 35 In the fourth embodiment described, the first filling insulation member GW1 is formed in various ways, such as being the same or similar, and is attached to both sides of the connecting insulation wall 3a by the bonding member 10, and then the connecting insulation wall 3a is inserted between adjacent fixed insulation walls 3b.

[0243] The following is for reference Figures 43 to 47 The structure of the slit formed in the liquefied gas storage tank 1 of this embodiment and the liquefied gas storage tank 1' of the comparative example, which connects the heat insulation wall 3a and the fixed heat insulation wall 3b, and the convection path and temperature difference that vary depending on whether the heat insulation filling element filling the slit is applied, are explained.

[0244] Figure 43 (a) and Figure 45 The liquefied gas storage tank 1 shown in this embodiment has the same structure as described above, with the connecting insulation wall 3a and the fixed insulation wall 3b. Right-angle corner structures and obtuse-angle corner structures are applied. Figure 25 and Figure 26 The structure shown is not limited to this; other right-angle corner structures and obtuse-angle corner structures can also be applied.

[0245] Figure 43 (b) shows a comparative example of a liquefied gas storage tank 1'. Compared with the liquefied gas storage tank 1 of this embodiment, the first slit SL1' has the same depth, but the difference is that the first filling insulation member GW1 is not filled. The difference of the second slit SL2' is that its depth is formed to be similar to the thickness of the fixed insulation wall 3b. Other than that, the structure can be the same or similar.

[0246] Figure 44 (a) shows the first convection path CP1, the second convection path CP2 and the third convection path CP3 in the liquefied gas storage tank 1 of this embodiment.

[0247] The first convection path CP1 is the path corresponding to the first slit SL1, which is formed in the gap between the connecting insulation wall 3a and the fixed insulation wall 3b. It can be confirmed that the convection blocking path CP1' is formed in the upper part of the first slit SL1 by the first filling insulation member GW1, so the path is only formed in the lower space of the first slit SL1.

[0248] The second convection path CP2 is a path corresponding to the second slit SL2, which is formed to a depth of about half the thickness of the fixed insulation wall 3b. It can be confirmed that the path is formed in the space of the second slit SL2, but is blocked in the portion of the first filling insulation GW1 that fills the first slit SL1.

[0249] The third convection path CP3 is the path corresponding to the third slit SL3, which is formed to a depth of about half the thickness of the connecting insulation wall 3a. It can be confirmed that the path is formed in the space of the third slit SL3, but is blocked in the portion of the first filling insulation GW1 that fills the first slit SL1.

[0250] Figure 44(b) shows the fourth convection path CP4, the fifth convection path CP5 and the sixth convection path CP6 in the liquefied gas storage tank 1' of the comparative example.

[0251] The fourth convection path CP4 is the path corresponding to the first slit SL1' which is formed in the gap between the connecting insulation wall 3a and the fixed insulation wall 3b. It can be confirmed that, unlike in this embodiment, the first slit SL1' is not filled with insulation material, so all the space portions of the first slit SL1' form paths.

[0252] The fifth convection path CP5 is the path corresponding to the second slit SL2' which is formed at a depth similar to the thickness of the fixed insulation wall 3b. It can be confirmed that the fifth convection path CP5 formed in the space portion of the second slit SL2' is connected to the fourth convection path CP4 formed in the space portion of the first slit SL1'.

[0253] The sixth convection path CP6 is a path corresponding to the third slit (not shown) formed at a depth similar to the thickness of the connecting insulation wall 3a. It can be confirmed that the sixth convection path CP6 formed in the space portion of the third slit is connected to the fourth convection path CP4 and the fifth convection path CP5.

[0254] As described above, in the liquefied gas storage tank 1 of this embodiment, it can be confirmed that the first convection path CP1, the second convection path CP2, and the third convection path CP3 are discontinuous with each other, and the convection area is reduced. In the liquefied gas storage tank 1' of the comparative example, it can be confirmed that the fourth convection path CP4, the fifth convection path CP5, and the sixth convection path CP6 are continuous, and the convection area is increased.

[0255] In addition, such as Figure 44 (b) shows that in the comparative example of the liquefied gas storage tank 1', the fourth convection path CP4, the fifth convection path CP5, and the sixth convection path CP6 respectively form convection spaces from the primary protective wall 2 to the secondary protective wall 4. Therefore, the temperature in the primary protective wall 2 directly affects the secondary protective wall 4, resulting in a severe temperature drop in the secondary protective wall 4. On the other hand, in the liquefied gas storage tank 1 of this embodiment, the first convection path CP1, the second convection path CP2, and the third convection path CP3 can respectively prevent the temperature in the primary protective wall 2 from being transferred to the secondary protective wall 4 through the first filling insulation member GW1. Therefore, compared with the liquefied gas storage tank 1' of the comparative example, the temperature drop in the secondary protective wall 4 of the liquefied gas storage tank 1 of this embodiment is less.

[0256] Due to this difference in convection paths, the secondary protective walls 4 of the liquefied gas storage tank 1 in this embodiment and the liquefied gas storage tank 1' in the comparative example also have temperature differences.

[0257] like Figure 45 and Figure 46 As shown, when multiple unit elements are arranged adjacently, a temperature sensor TL is attached to the secondary protective wall 4 in the space formed between adjacent secondary insulation walls 5.

[0258] With the temperature of the protective wall 2 at -196 degrees Celsius and the temperature of the hull 7 at 10 degrees Celsius, the temperature measured by the temperature sensor TL showed that the liquefied gas storage tank 1 in this embodiment was -79.3 degrees Celsius, while the liquefied gas storage tank 1' in the comparative example was -100.9 degrees Celsius. As described above, it can be confirmed that this result occurs because, compared to the liquefied gas storage tank 1' in the comparative example, the convection path of the liquefied gas storage tank 1 in this embodiment is discontinuous and the convection area is reduced.

[0259] Figure 47 This is a graph comparing the temperature of the secondary protective wall 4 at the bottom of the first slit SL1 and SL1' when the first slit SL1 of the liquefied gas storage tank 1 in this embodiment is filled with the first filling insulation member GW1, while the first slit SL1' of the liquefied gas storage tank 1' in the comparative example is not filled with the filling insulation member.

[0260] When the temperature of the primary protective wall 2 is -196 degrees and the temperature of the hull 7 is 10 degrees, when the height of the first slits SL1 and SL1' is 0.2 mm, the temperature of the secondary protective wall 4 below the first slit SL1 in this embodiment, which is filled with the first heat-insulating filler GW1, is about -90 degrees (curve A). The temperature of the secondary protective wall 4 below the first slit SL1' in the comparative example, which is not filled with the heat-insulating filler, is about -150 degrees (curve B).

[0261] Therefore, it can be confirmed that, compared with the liquefied gas storage tank 1' of the comparative example, the temperature drop in the secondary protective wall 4 of the liquefied gas storage tank 1 of this embodiment is less (preventing heat convection).

[0262] Figure 48 This is a partial cross-sectional view of a liquefied gas storage tank used to illustrate the sixth embodiment of the present invention. Figure 49 It is along Figure 48 A cross-sectional view of the connecting insulation wall cut along line A-A'. Figure 50 It is along Figure 48 A cross-sectional view of a unit element consisting of a secondary insulation wall, a secondary protective wall, and a fixed insulation wall that forms the primary insulation wall, cut along line B-B'. Figure 51 This is an enlarged view showing the state in which the filling insulation element is filled in the first slit that forms a gap between the connecting insulation wall and the fixed insulation wall that constitute the primary insulation wall.

[0263] like Figures 48 to 51As shown, the liquefied gas storage tank 1 of the sixth embodiment of the present invention may include: a primary protective wall 2 that is in contact with the liquefied gas inside; a primary heat insulation wall 3 that is disposed outside the primary protective wall 2 and is composed of a connecting heat insulation wall 3a and a fixed heat insulation wall 3b; a secondary protective wall 4 disposed outside the primary heat insulation wall 3; and a secondary heat insulation wall 5 disposed outside the secondary protective wall 4 and fixed to the hull 7. Compared with the fifth embodiment described above, the stepped portions ST1 and ST2 formed on the sides of the connecting heat insulation wall 3a and the fixed heat insulation wall 3b are different, while other structures are the same or similar. Therefore, the following description focuses on the different parts to avoid repetition.

[0264] As mentioned above, the primary insulation wall 3 and the secondary insulation wall 5 in this embodiment can have the same or similar thickness.

[0265] The primary insulation wall 3 can be composed of a connecting insulation wall 3a and a fixed insulation wall 3b. In this case, the connecting insulation wall 3a can be inserted between adjacent fixed insulation walls 3b when multiple unit elements including the fixed insulation wall 3b are arranged adjacently, so as to seal the space formed between adjacent secondary insulation walls 5.

[0266] like Figure 48 and Figure 49 As shown, the connecting insulation wall 3a can be divided into an upper part and a lower part. The front-back and left-right width of the upper part is smaller than that of the lower part. Therefore, a first step part ST1 with a positive shape can be formed on the front-back and left-right sides of the connecting insulation wall 3a.

[0267] The upper and lower parts of the connecting insulation wall 3a can be divided based on a position approximately half the thickness of the connecting insulation wall 3a, but this is not the only limitation. The depth can be determined based on the depth of the third slit SL3, which has a depth similar to the thickness of the connecting insulation wall 3a, as will be understood later. Here, when one or more third slits SL3 are formed along the length direction of the connecting insulation wall 3a, and the connecting insulation wall 3a is inserted between the fixed insulation walls 3b, the third slit SL3 can be located on the same line as the second slit SL2 formed along the length direction.

[0268] In addition, such as Figure 48 and Figure 49 As shown, a chamfer CH with a negative shape can be formed at the bottom corner of the connecting insulation wall 3a.

[0269] When the connecting insulation wall 3a is placed between adjacent fixed insulation walls 3b, the chamfer CH facilitates insertion.

[0270] like Figure 48 and Figure 50As shown, the fixed heat insulation wall 3b can be divided into an upper part and a lower part. The front-back and left-right width of the upper part is smaller than that of the lower part. Therefore, a second step part ST2 with a positive shape can be formed on the front-back and left-right sides of the fixed heat insulation wall 3b.

[0271] The upper and lower parts of the fixed heat insulation wall 3b can be divided based on a position approximately half the thickness of the fixed heat insulation wall 3b, but are not limited thereto. They can be determined based on the depth of the second slit SL2, which has a depth similar to the thickness of the fixed heat insulation wall 3b, as will be understood later.

[0272] In the above, the first step portion ST1 and the second step portion ST2 can be the same or similar in shape. When the connecting heat insulation wall 3a is inserted between adjacent fixed heat insulation walls 3b, they face each other and define a space, thereby forming a first slit SL1 between the connecting heat insulation wall 3a and the fixed heat insulation wall 3b for the first filling heat insulation member GW1 to fill.

[0273] That is, when the first step PS1 divides the connecting heat insulation wall 3a into an upper and lower part, the front-back and left-right width of the upper part is made smaller than that of the lower part. When the second step PS2 divides the fixed heat insulation wall 3b into an upper and lower part, the front-back and left-right width of the upper part is made smaller than that of the lower part. At this time, the first filling heat insulation member GW1 can fill the first slit SL1 formed between the upper part of the connecting heat insulation wall 3a and the upper part of the fixed heat insulation wall 3b by being adjacent to the lower part of the connecting heat insulation wall 3a and the lower part of the fixed heat insulation wall 3b. The first filling heat insulation member GW1 filling the first slit SL1 can be formed with a (+) tolerance so that the space can be completely sealed when filled in the space of the first slit SL1. Therefore, even if the connecting heat insulation wall 3a and the fixed heat insulation wall 3b contract and expand, a heat convection path will not be formed in the first slit SL1.

[0274] For example, in order to insert the first filling insulation GW1 with a thickness of 10mm into the first slit SL1, considering the compressed state of the first filling insulation GW1, the width of the first slit SL1 must be at least about 6mm. Therefore, in this embodiment, the width between the lower side of the connecting insulation wall 3a and the lower side of the fixed insulation wall 3b can be set to 2mm (typically, the distance between the connecting insulation wall and the fixed insulation wall). The width of the first step portion ST1 provided on the connecting insulation wall 3a can be formed to 2mm, and the width of the second step portion ST2 provided on the fixed insulation wall 3b can be formed to 2mm. Since the thickness of the first filling insulation GW1 filling the first slit SL1 can be changed, the width of the first step portion ST1 and the second step portion ST2 in this embodiment can also be changed.

[0275] In this embodiment, the depth of the first step portion ST1 and the second step portion ST2 forming the first slit SL1 is not particularly limited if a second slit SL2 or a third slit SL3 with a depth corresponding to about half the thickness of the fixed heat insulation wall 3b or the connecting heat insulation wall 3a is not formed. However, if a second slit SL2 or a third slit SL3 is formed, it needs to be limited in order to prevent heat convection.

[0276] That is, as described in the fifth embodiment, considering that in order to prevent heat convection caused by the slit, the first filling insulation GW1 filling the first slit SL1 needs to be formed to a greater depth than the second slit SL2 or the third slit SL3, the depth of the first slit SL1 filling the first filling insulation GW1 in this embodiment needs to be formed to a greater depth than the depth of the second slit SL2 and the third slit SL3.

[0277] For example, if the depth of the second slit SL2 and the third slit SL3 without the filling insulation is 90 mm, the depth of the first slit SL1 filled with the first filling insulation GW1 needs to be formed to a depth of at least 90 mm, for example, a depth of 105 mm.

[0278] Figure 52 This is a perspective view illustrating the liquefied gas storage tank according to the seventh embodiment of the present invention. Figure 53 (a) to (c) respectively show Figure 52 Top view, side view, and sectional view of the unit elements consisting of a secondary insulation wall, a secondary protective wall, and a fixed insulation wall that constitutes the primary insulation wall. Figure 54 (a) to (c) respectively show the components Figure 52 Top view, side view, and sectional view of the primary insulation wall connection. Figure 55 (a) to (c) respectively show the components Figure 52 Top view, side view, and cross-sectional view of another embodiment of the primary insulation wall. Figure 56 It constitutes Figure 52 A perspective view of the back of the connecting insulation wall in another embodiment of the primary insulation wall. Figure 57 This is a cross-sectional view showing the alternating connection of fixed insulation walls and connecting insulation walls that constitute a primary insulation wall. Figure 58 It is a cross-sectional view showing the continuous connection of a plurality of connected insulation walls that constitute a primary insulation wall.

[0279] In the above, Figure 53 (c) is along Figure 53 A cross-sectional view of the connecting insulation wall cut along line A-A' in (a). Figure 54 (c) is along Figure 54A cross-sectional view of the connecting insulation wall cut along line B-B' in (a). Figure 55 (c) is along Figure 55 A cross-sectional view of the connecting insulation wall cut along line C-C' in (a).

[0280] like Figures 52 to 58 As shown, the liquefied gas storage tank 1 of the seventh embodiment of the present invention may include: a primary protective wall that is in contact with the liquefied gas inside; a primary heat insulation wall 3 disposed on the outside of the primary protective wall and composed of a connecting heat insulation wall 3a and a fixed heat insulation wall 3b; a secondary protective wall 4 disposed on the outside of the primary heat insulation wall 3; and a secondary heat insulation wall 5 disposed on the outside of the secondary protective wall 4 and fixed to the hull 7. Compared with the aforementioned fifth embodiment, the difference is that the stepped portions PS1, PS2, PS3, and PS4 are respectively formed on the sides of the connecting heat insulation wall 3a and the fixed heat insulation wall 3b, and the stepped portions PS1, PS2, PS3, and PS4 are finished by heat insulation plates IP1 and IP2. Other structures are the same or similar, so the following description focuses on the different parts to avoid repetition.

[0281] As mentioned above, the primary insulation wall 3 and the secondary insulation wall 5 in this embodiment can have the same or similar thickness.

[0282] The primary insulation wall 3 can be composed of a connecting insulation wall 3a and a fixed insulation wall 3b. In this case, the connecting insulation wall 3a can be inserted between adjacent fixed insulation walls 3b when multiple unit elements including the fixed insulation wall 3b are arranged adjacently, to seal the space formed between adjacent secondary insulation walls 5. Hereinafter, the front, rear, left, and right sides of the fixed insulation wall 3b are defined as the sides connected to the front and rear sides of the connecting insulation wall 3a, and the left and right sides of the connecting insulation wall 3a are defined as the sides connected to the left or right side of another adjacent connecting insulation wall 3a.

[0283] like Figure 52 and Figure 53 As shown in (a) to (c), the fixed heat insulation wall 3b can be divided into an upper part and a lower part. The upper part and the lower part of the fixed heat insulation wall 3b can be divided based on a position of about half the thickness of the fixed heat insulation wall 3b, but are not limited to this.

[0284] The upper front-to-back and left-to-right width of the fixed heat insulation wall 3b is smaller than the lower front-to-back and left-to-right width, so that a first step part PS1 with a positive shape can be formed on its front-to-back and left-to-right sides.

[0285] like Figure 57As shown, the first step portion PS1 can overlap with the front and rear sides of the second step portion PS2, the third step portion PS3, or the fourth step portion PS4 formed on the connecting heat insulation wall 3a (described later) on the front, rear, left, and right sides of the fixed heat insulation wall 3b to form a first slit SL1. A first heat insulation plate IP1 can be attached to the first step portion PS1 of the fixed heat insulation wall 3b, and the first heat insulation plate IP1 will be described later.

[0286] like Figure 52 , Figure 54 (a) to (c) and Figure 56 As shown in (a) to (c), the connecting insulation wall 3a can be divided into an upper part and a lower part. The upper and lower parts of the connecting insulation wall 3a can be divided based on a position of approximately half the thickness of the connecting insulation wall 3a, but are not limited to this.

[0287] The connecting insulation wall 3a is inserted into the linear space formed between two adjacent fixed insulation walls 3b, such as... Figure 54 As shown in (a) to (c), the front-to-back width of the upper part is greater than the front-to-back width of the lower part, and the left-to-right width of the upper part is less than the left-to-right width of the lower part, so that a second step PS2 can be formed on the front, back, left and right sides.

[0288] like Figure 54 As shown in (b), the second step PS2 can form a positive shape on the left and right sides connecting the heat insulation wall 3a, such as Figure 54 As shown in (c), the second step PS2 can form an inverted shape on the front and rear sides of the connecting insulation wall 3a.

[0289] like Figure 58 As shown, when a plurality of other connecting heat insulation walls are successively inserted into a straight-shaped space formed between two adjacent fixed heat insulation walls 3b, the second step portion PS2, which is formed in a positive shape on the left and right sides of the connecting heat insulation wall 3a, can overlap with the step portion formed in a negative shape on the side of the adjacent connecting heat insulation wall to form a fourth slit SL4. A second heat insulation plate IP2 can be formed on the second step portion PS2, which is formed in a positive shape on the left and right sides of the connecting heat insulation wall 3a. The second heat insulation plate IP2 will be described later. Among them, as Figure 55 As shown in (b), the other connecting insulation wall can be a connecting insulation wall 3a with a reverse-shaped third step portion PS3 formed on one side, or as shown in (b). Figure 56 As shown, the connecting heat insulation wall 3a may be a fourth step portion PS4 with an inverted shape formed in the recessed portion on the front, back, left and right sides.

[0290] like Figure 57As shown, when the second step portion PS2, which forms an inverted shape on the front and rear sides of the connecting heat insulation wall 3a, is inserted between two adjacent fixed heat insulation walls 3b, it can overlap with the first step portion PS1, which forms an upright shape on the front, rear, left and right sides of the fixed heat insulation wall 3b, and form a first slit SL1.

[0291] Additionally, the connecting insulation wall 3a is inserted into the linear space formed between two adjacent fixed insulation walls 3b, such as... Figure 55 As shown in (a) to (c), the front-to-back width of the upper part is greater than that of the lower part, and the left-to-right width of the upper part is the same as that of the lower part and is offset from the left and right sides, so that a third step PS3 can be formed on the front, back, left and right sides.

[0292] like Figure 55 As shown in (b), the third step PS3 can be formed in a reverse shape on one of the left and right sides connecting to the heat insulation wall 3a, and in a positive shape on the other side, as shown in (b). Figure 54 As shown in (c), the front and rear sides of the connecting insulation wall 3a can be formed in reverse shape.

[0293] like Figure 58 As shown, when a plurality of other connecting insulation walls are successively inserted into a straight-shaped space formed between two adjacent fixed insulation walls 3b, the third step portion PS3, which is formed in an inverted shape on the left and right sides of the connecting insulation wall 3a, can overlap with the step portion, which is formed in a positive shape on the side of the adjacent connecting insulation wall, to form a fourth slit SL4. Wherein, as Figure 54 As shown in (b), another connecting heat insulation wall can be a connecting heat insulation wall 3a with a positively shaped second step portion PS2 formed on the left and right sides, or as shown in (b). Figure 55 As shown in (b), the connecting heat insulation wall 3a may be formed on the other side with a positive shape third step PS3.

[0294] like Figure 58 As shown, when a plurality of other connecting heat insulation walls are successively inserted into a straight-shaped space formed between two adjacent fixed heat insulation walls 3b, the third step portion PS3, which is formed in a positive shape on the left and right sides of the connecting heat insulation wall 3a, can overlap with the step portion formed in a negative shape on the side of the adjacent connecting heat insulation wall to form a fourth slit SL4. A second heat insulation plate IP2 can be formed on the third step portion PS3, which is formed in a positive shape on the left and right sides of the connecting heat insulation wall 3a. The second heat insulation plate IP2 will be described later. Among them, as Figure 55 As shown in (b), the other connecting insulation wall can be a connecting insulation wall 3a with a reverse-shaped third step portion PS3 formed on one side, or as shown in (b). Figure 56As shown, the connecting heat insulation wall 3a may be a fourth step portion PS4 with an inverted shape formed in the recessed portion on the front, back, left and right sides.

[0295] In addition, such as Figure 56 As shown, the connecting heat insulation wall 3a is inserted into the intersecting space formed between four adjacent fixed heat insulation walls 3b. The upper front-back and left-right width can be formed to be greater than the lower front-back and left-right width, and a fourth step PS4 can be formed on the front-back and left-right sides.

[0296] The fourth step PS4 can form an inverted shape on the protrusions and recesses on the front, back, left and right sides of the heat insulation wall 3a.

[0297] like Figure 58 As shown, when the fourth step portion PS4, which forms a reverse shape on the protrusions of the front, rear, left, and right sides of the connecting insulation wall 3a, is inserted into the intersecting spatial portion formed between four adjacent fixed insulation walls 3b, it can overlap with the step portion formed in a positive shape on the side of another connecting insulation wall in the straight spatial portion formed between two adjacent fixed insulation walls 3b, thus forming a fourth slit SL4. Wherein, as... Figure 54 As shown in (b), another connecting heat insulation wall can be a connecting heat insulation wall 3a with a positively shaped second step portion PS2 formed on the left and right sides, or as shown in (b). Figure 55 As shown in (b), the connecting heat insulation wall 3a may be formed on the other side with a positive shape third step PS3.

[0298] like Figure 57 As shown, when the fourth step portion PS4, which forms an inverted shape in the recessed portion connecting the front, rear, left, and right sides of the heat insulation wall 3a, is inserted into the intersecting space portion formed between the four adjacent fixed heat insulation walls 3b, it can overlap with the first step portion PS1, which forms an upright shape in the front, rear, left, and right sides of each of the four adjacent fixed heat insulation walls 3b, and form the first slit SL1.

[0299] like Figure 57As shown, when the connecting heat insulation wall 3a is inserted between adjacent fixed heat insulation walls 3b, a first reverse step portion formed on the side of the connecting heat insulation wall 3a overlaps the first positive step portion formed on the side of the fixed heat insulation wall 3b. Therefore, the first slit SL1 of this embodiment has a shape that bends towards the space formed between the fixed heat insulation wall 3b and the connecting heat insulation wall 3a. The first positive step portion formed on the side of the fixed heat insulation wall 3b can be a positive first step portion PS1 formed on the front, rear, left, and right sides of the fixed heat insulation wall 3b. The first reverse step portion formed on the side of the connecting heat insulation wall 3a can be a second step portion PS2, a third step portion PS3 formed on the front and rear sides of the connecting heat insulation wall 3a, or a fourth step portion PS4 formed in the recessed portion on the front, rear, left, and right sides of the connecting heat insulation wall 3a.

[0300] Compared to a slit with a straight shape, the first slit SL1 with a curved shape can reduce heat convection, but heat convection may occur in the space through the first slit SL1.

[0301] Therefore, in this embodiment, the first heat insulation plate IP1 is attached to the first step portion PS1, which is formed in a positive shape on the front, back, left and right sides of the fixed heat insulation wall 3b, so as to prevent heat convection.

[0302] The first heat insulation plate IP1 can be attached to the first positive step portion formed on the side of the fixed heat insulation wall 3b opposite to the connecting heat insulation wall 3a. When the connecting heat insulation wall 3a is disposed between adjacent fixed heat insulation walls 3b, the first heat insulation plate IP1 can be pressed by the first reverse step portion formed on the side of the connecting heat insulation wall 3a opposite to the fixed heat insulation wall 3b in a state of not being attached to the connecting heat insulation wall 3a, thereby blocking the space portion of the first slit SL1.

[0303] The first insulation panel IP1 can be formed of insulation materials such as glass wool, but is not limited to this.

[0304] In addition, such as Figure 58As shown, the fourth slit SL4 in this embodiment is a space formed between adjacent connecting heat insulation walls 3a when multiple connecting heat insulation walls 3a are continuously arranged. This space is formed by overlapping a second positive step portion formed on the side surface of any one of the connecting heat insulation walls 3a with a second negative step portion formed on the side surface of another connecting heat insulation wall 3a, and has a curved shape. The second positive step portion formed on the side surface of any one connecting heat insulation wall 3a can be a second step portion PS2 or a third step portion PS3 formed on at least one of the left or right sides of the connecting heat insulation wall 3a. The second negative step portion formed on the side surface of another connecting heat insulation wall 3a can be a third step portion PS3 formed on at least one of the left or right sides of the connecting heat insulation wall 3a, or it can be a fourth step portion PS4 formed on the protrusions on the front, rear, left, and right sides of the connecting heat insulation wall 3a.

[0305] Compared to slits with a straight shape, the fourth slit SL4, which has a curved shape, can reduce thermal convection, but thermal convection may occur in the space through the fourth slit SL4.

[0306] Therefore, in this embodiment, the second heat insulation plate IP2 is attached to the second positive step portion or the second negative step portion formed on the left and right sides of the adjacent connecting heat insulation wall 3a to prevent heat convection.

[0307] The second heat insulation plate IP2 can be attached to the second positive step portion formed on the side of any one of the adjacent connecting heat insulation walls 3a. When the adjacent connecting heat insulation walls 3a are continuously arranged between the adjacent fixed heat insulation walls 3b, the second heat insulation plate IP2 can be pressed by the second reverse step portion formed on the side of the other connecting heat insulation wall 3a, thereby blocking the space portion of the fourth slit SL4.

[0308] The second insulation panel IP2 can be formed of insulation materials such as glass wool, but is not limited to these.

[0309] In the above embodiment, the widths of the first step portion PS1, the second step portion PS2, the third step portion PS3, and the fourth step portion PS4 can be the same or similar, for example, 30mm, and are not limited thereto.

[0310] In addition, the widths of the first slit SL1 and the fourth slit SL4 can be the same or similar. For example, the width between the upper side of the heat insulation wall 3a and the upper side of the fixed heat insulation wall 3b can be 2 mm, and the width between the lower side of the heat insulation wall 3a and the lower side of the fixed heat insulation wall 3b can be 2 mm, and is not limited to this.

[0311] In addition, the thickness and width of the first heat insulation plate IP1 and the second heat insulation plate IP2 can be the same or similar. For example, the thickness can be 10 mm and the width can be 30 mm, and it is not limited to this.

[0312] As described above, in this embodiment, by making the thickness of the primary heat insulation wall 3 and the secondary heat insulation wall 5, which include the connecting heat insulation wall 3a, the thickness of the primary heat insulation wall 3 and 3a the same as or similar to that of the secondary heat insulation wall 5, not only can the mechanical strength of the secondary heat insulation wall 5 be maintained at a predetermined level, but also the low temperature load and shaking load of the secondary protective wall 4 can be reduced, thereby preventing damage to the secondary protective wall 4.

[0313] In addition, in this embodiment, by providing an auxiliary heat insulation plate 33 on the bottom surface of the connecting heat insulation wall 3a arranged in the space between adjacent primary heat insulation walls 3 constituting the unit element, the heat insulation performance of the connecting portion of the adjacent secondary heat insulation walls 5 constituting the unit element can be further improved.

[0314] In addition, this embodiment can improve the thermal insulation performance by improving the structure of the secondary protective wall 4.

[0315] In addition, in this embodiment, by using the unattached elastic insulation element as a leveling component 8 between the secondary insulation wall 5 and the hull 7, the level of the deformed part of the hull 7 can be adjusted even without using conventional adhesives and leveling wedges, and the heat insulation performance of the tank can be improved.

[0316] In addition, in this embodiment, the adjacent unit panel of the secondary heat insulation wall 5 is fixed by using a clamping structure consisting of a protrusion 91 that protrudes outward from the lower side of the unit panel of the secondary heat insulation wall 5 and a stud 92 fixed to the hull 7. This method saves labor compared to drilling holes in the secondary heat insulation wall 5 and fixing the unit panel with studs.

[0317] Furthermore, in this embodiment, by improving the slit structure and making the filling insulation component that fills the slits varied, the slits provided to cope with the contraction and expansion of the primary insulation wall 3 formed on the secondary protective wall 4 are optimized, and the convection phenomenon generated through the slits and the heat penetration into the secondary protective wall 4 are minimized. This improves the stability of the primary insulation wall 3 formed based on the slits and reduces the low-temperature burden on the secondary protective wall 4, thereby preventing damage to the primary insulation wall 3 and the secondary protective wall 4.

[0318] This invention is not limited to the embodiments described above. Another embodiment may include a combination of the above embodiments or a combination of at least one of the above embodiments and known technologies. For example, Figures 28 to 29 The embodiments can be related to Figures 4 to 27 Combinations of embodiments. Additionally, for example, Figures 30 to 31 The embodiments can be related to Figure 1 and Figure 2 insulation system or Figure 28 and Figure 29 The combination of thermal insulation systems. Additionally, for example, Figures 32 to 58 The embodiments can be related to Figures 1 to 31 Examples of combinations.

[0319] Although the present invention has been described in detail above with reference to specific embodiments, it is only for the purpose of illustrating the present invention. The present invention is not limited thereto, and those skilled in the art can make modifications or improvements within the technical concept of the present invention.

[0320] Simple variations or modifications of this invention are all within the scope of this invention, and the specific scope of protection of this invention will be further clarified by the scope of the appended claims.

[0321] Explanation of reference numerals in the attached figures

[0322] 1, 1': Liquefied gas storage tank; 2: Primary protective wall

[0323] 21: Flat surface 22: Curved surface

[0324] 23: Boundary section 3: Primary insulation wall

[0325] 3b: Fixed insulation wall; 31: Primary clamping plate

[0326] 32: Primary insulation component 3a: Connecting insulation wall

[0327] 31a: Connecting clamp plate; 32a: Connecting heat insulation component

[0328] 33: Auxiliary heat insulation board; 4: Secondary protective wall

[0329] 41: Main protective wall; 42: Auxiliary protective wall

[0330] GAC: Glass-aramid fabric; AF: Aluminum foil

[0331] GC: Glass fabric; BC: Basalt fabric

[0332] 5: Secondary insulation wall; 51: Secondary insulation component

[0333] 52: Secondary plywood; 6: Adhesive.

[0334] 7: Hull 8: Leveling components

[0335] 9: Fixing component 91: Protrusion

[0336] 92: Stud; 10: Fitting component

[0337] SL1, SL1': First slit; SL2, SL2': Second slit

[0338] SL3: Third slit; SL4: Fourth slit

[0339] GW1: First filling insulation component; GW1-1: First upper filling insulation component

[0340] GW1-2: First intermediate insulation component; GW1-3: First lower insulation component

[0341] GW2: Second filling insulation component; GW2-1: Second upper filling insulation component

[0342] GW2-2: Second intermediate insulation component; GW2-3: Second lower insulation component

[0343] CP1: First convection path; CP1': Convection blocking path

[0344] CP2: Second convection path; CP3: Third convection path

[0345] CP4: Fourth convection path; CP5: Fifth convection path

[0346] CP6: Sixth convection path; TL: Temperature sensor

[0347] ST1: First step section; ST2: Second step section

[0348] CH: Chamfered IP1: First heat insulation plate

[0349] IP2: Second heat insulation plate; PS1: First step section

[0350] PS2: Second Step PS3: Third Step

[0351] PS4: Fourth Step

Claims

1. A liquefied gas storage tank, wherein, The liquefied gas storage tank consists of a primary protective wall, a primary insulation wall, a secondary protective wall, and a secondary insulation wall, and stores extremely low temperature substances. The primary insulation wall includes: In a configuration where unit elements consisting of the secondary insulation wall, the secondary protective wall, and a fixed insulation wall that is part of the primary insulation wall are stacked adjacent to each other, the connecting insulation wall is disposed in the space between adjacent fixed insulation walls. The liquefied gas storage tank includes: The first slit is formed between the fixed heat insulation wall and the connecting heat insulation wall when the connecting heat insulation wall is inserted between the adjacent fixed heat insulation walls. The second slit is formed in a plurality of forms along the length and width directions of the fixed heat insulation wall; A first insulating filler fills the first slit; and The third slit is formed in one or more along the length direction of the connecting heat insulation wall, and when the connecting heat insulation wall is inserted between the fixed heat insulation walls, it is located on the same line as the second slit formed along the length direction; The first insulating filler is formed to be at least longer than the depths of both the second and third slits. The heat convection path formed by the first slit, the second slit, and the third slit is discontinuous.

2. The liquefied gas storage tank according to claim 1, wherein, The first insulating filler is formed to completely fill the first slit. Alternatively, the first filling insulation element can be formed to fill from the entrance of the first slit to a predetermined depth, thereby creating a space at the lower part of the first slit. Alternatively, the first filling insulation element may be formed to fill the interior of the first slit in a multi-layered manner, thereby forming a plurality of spaces inside the first slit.

3. The liquefied gas storage tank according to claim 2, wherein, When the first insulating filler is formed to fill the interior of the first slit in a multi-layered manner, thereby creating a plurality of spaces within the first slit, The first heat insulation component includes: A first upper heat-insulating element is formed on the upper part of the first slit; A first intermediate filling insulation member is formed in the middle of the first slit, spaced apart from the first upper filling insulation member by a predetermined interval; and A first lower filling insulation element is formed at the lower part of the first slit, spaced apart from the first intermediate filling insulation element by a predetermined interval. The first upper filling insulation component, the first middle filling insulation component, and the first lower filling insulation component are each formed of the same insulation component or different insulation components. The insulation component is one of glass wool, supercrystal stone, soft foam material, or aerogel blanket.

4. The liquefied gas storage tank according to claim 1, wherein, After the connecting insulation wall is inserted between the adjacent fixed insulation walls, the first filling insulation member fills the first slit by inserting a clamp. Alternatively, with the first filling insulation member attached to the two sides of the connecting insulation wall opposite to the side of the fixed insulation wall using an adhesive member, the first slit can be filled by inserting the connecting insulation wall between adjacent fixed insulation walls.

5. The liquefied gas storage tank according to claim 1, wherein, When the depth of the second slit is formed to be similar to the thickness of the fixed heat insulation wall, a second heat insulation filler is inserted into the interior of the second slit. The second filling insulation element is formed to fill from the entrance of the second slit to a predetermined depth, so as to form a space at the lower part of the second slit. Alternatively, the second filling insulation element may be formed to fill the interior of the second slit in a multi-layered manner to create a plurality of spaces inside the second slit.

6. The liquefied gas storage tank according to claim 5, wherein, When the second insulating filler is formed to fill the interior of the second slit in a multi-layered manner, thereby creating a plurality of spaces within the second slit, The second heat insulation filler includes: A second upper heat-insulating element is formed in the upper part of the second slit; A second intermediate heat-insulating member is formed in the middle of the second slit, spaced apart from the second upper heat-insulating member by a predetermined interval; and The second lower filling insulation element is separated from the second intermediate filling insulation element by a predetermined interval and is formed at the lower part of the second slit. The second upper filling insulation, the second middle filling insulation, and the second lower filling insulation are each formed of the same insulation or different insulations. The insulation component is one of glass wool, supercrystal stone, soft foam material, or aerogel blanket.

7. The liquefied gas storage tank according to claim 1, wherein, The second slit and the third slit are formed to a depth corresponding to half the thickness of the fixed insulation wall and the connecting insulation wall, and the interior of the second slit and the third slit is not filled with insulation material.

8. The liquefied gas storage tank according to claim 1, wherein, The primary insulation wall and the secondary insulation wall have the same or similar thickness.

9. A liquefied gas storage tank, wherein, The liquefied gas storage tank consists of a primary protective wall, a primary insulation wall, a secondary protective wall, and a secondary insulation wall, and stores extremely low temperature substances. The primary insulation wall includes: In a configuration where unit elements consisting of the secondary insulation wall, the secondary protective wall, and a fixed insulation wall that is part of the primary insulation wall are stacked adjacent to each other, the connecting insulation wall is disposed in the space between adjacent fixed insulation walls. The liquefied gas storage tank includes: The first step is formed on the front, back, left and right sides of the connecting heat insulation wall; The second step is formed on the front, back, left and right sides of the fixed heat insulation wall; The first slit is formed between the connecting heat insulation wall and the fixed heat insulation wall when the connecting heat insulation wall is inserted between the adjacent fixed heat insulation wall and the fixed heat insulation wall by the first step portion and the second step portion. A first insulating filler is used to fill the first slit. The second slit is formed in a plurality of slits along the length and width directions of the fixed heat insulation wall; and The third slit is formed in one or more along the length direction of the connecting heat insulation wall, and when the connecting heat insulation wall is inserted between the fixed heat insulation walls, it is located on the same line as the second slit formed along the length direction; The first insulating filler is formed to be at least longer than the depth of each of the second and third slits; The heat convection path formed by the first slit, the second slit, and the third slit is discontinuous.

10. The liquefied gas storage tank according to claim 9, wherein, The first stepped portion is formed by making the upper part of the connecting heat insulation wall narrower in all directions than the lower part of the connecting heat insulation wall. The second stepped portion is formed by making the upper part of the fixed heat insulation wall narrower in all directions than the lower part of the fixed heat insulation wall. The first filling insulation element fills the first slit, which is formed in the space between the upper part of the connecting insulation wall and the upper part of the fixed insulation wall by the lower part of the connecting insulation wall and the lower part of the fixed insulation wall being adjacent to each other.

11. The liquefied gas storage tank according to claim 10, wherein, The second slit and the third slit are formed to a depth corresponding to half the thickness of the fixed insulation wall and the connecting insulation wall, and the interior of the second slit and the third slit is not filled with insulation material.

12. The liquefied gas storage tank according to claim 9, wherein, The primary insulation wall and the secondary insulation wall have the same or similar thickness.

Images