Insulation structure for liquified gas storage tank and method for forming the insulation structure

Abstract

The present invention relates to an insulation structure for a liquefied gas storage tank for insulating liquefied gas stored inside a tank body, comprising: a composite layer installed to surround the tank body; an insulating portion formed by applying it on the composite layer; and a fixing portion for fixing the composite layer to the tank body, wherein the composite layer is composed of a laminated metal film capable of watertightness or airtightness and a glass fiber-based reinforcing sheet.

Description

Technology Field

[0001] The present invention relates to an insulation structure for a liquefied gas storage tank for storing liquefied gas, and more specifically, to an insulation structure for a liquefied gas storage tank and a method for forming the insulation structure of said liquefied gas storage tank, wherein the insulation layer is formed on the outer wall of the tank by a spraying method, thereby ensuring the integrity of the insulation layer to maintain insulation performance, and at the same time providing a broad function of a secondary barrier for the effective detection and discharge of leaked gas. Background Technology

[0002] Due to the recent tightening of environmental pollution regulations for ships, interest in eco-friendly, high-efficiency liquefied gas fuels, such as Liquefied Natural Gas (LNG) or Liquefied Petroleum Gas (LPG), is increasing.

[0003] Liquefied natural gas is obtained by cooling and liquefying methane produced by refining natural gas extracted from gas fields, while liquefied petroleum gas is a fuel made by compressing gases composed mainly of propane and butane, which are found along with petroleum in oil fields, into a liquid at room temperature.

[0004] In particular, liquefied natural gas (hereinafter referred to as 'LNG') is obtained by cooling natural gas to a cryogenic temperature (about -163°C), and since its volume is reduced to approximately 1 / 600 of that of natural gas in a gaseous state, it is very suitable for long-distance transportation by sea.

[0005] Liquefied gas is transported in a gaseous state through onshore or offshore gas pipelines, or transported to distant consumption sites while stored in a liquid state on transport vessels.

[0006] Liquefied gas carriers that transport liquefied gas, such as LNG, to sail the seas and unload the liquefied gas at onshore destinations, or LNG RVs (Regasification Vessels) that transport LNG to sail the seas, arrive at onshore destinations, and then regasify the stored LNG to unload it in the form of natural gas, are equipped with liquefied gas storage tanks (commonly referred to as 'cargo tanks') capable of withstanding the cryogenic temperatures of LNG.

[0007] In addition, liquefied gas storage tanks installed on LNG carriers or LNG RVs are also included in offshore structures such as LNG FPSO (Floating, Production, Storage and Offloading), which is used to liquefy and store produced natural gas directly at sea and transfer the stored LNG to an LNG carrier when necessary, and LNG FSRU (Floating Storage and Regasification Unit), which stores LNG unloaded from an LNG carrier at sea and then vaporizes the LNG as needed to supply it to onshore demand centers.

[0008] These liquefied gas storage tanks can be classified into membrane type and independent type depending on whether the load of the cargo acts directly on the insulation material.

[0009] Membrane-type storage tanks are divided into No. 96 and Mark III types, and independent storage tanks are divided into Type A, Type B, and Type C according to the regulations of the International Maritime Organization (IMO). Among these, Type B independent storage tanks include spherical MOSS tanks and prismatic SPB tanks.

[0010] The membrane-type storage tank is directly connected to the structure of the hull and is not separated from the hull, and has a structure in which a primary barrier and a secondary barrier are laminated on the inner wall of the hull. As the membrane-type tank is directly connected to the hull, the load of the liquefied gas stored inside is not supported by the storage tank but is transferred to the hull.

[0011] In contrast, standalone storage tanks are manufactured to be mounted on the hull separately from the hull structure and feature a structure in which insulation surrounds the outer walls. Since standalone storage tanks are separated from the hull and supported by support structures installed inside the hull, the load of the liquefied gas stored inside acts directly on the tank.

[0012] Unlike membrane storage tanks, independent storage tanks do not have a complex barrier structure and are relatively advantageous in terms of structural stability against sloshing compared to membrane storage tanks. In addition, since insulation is provided on the outer wall of the storage tank, maintenance by workers becomes easier.

[0013] The aforementioned technical configuration is provided as background technology to aid in understanding the present invention and does not constitute prior art widely known in the technical field to which the present invention belongs. Prior art literature

[0014] Korean Registered Patent Publication No. 10-1034472 "Insulation structure of independent liquefied gas tank and method of forming the same" The problem to be solved

[0015] An independent storage tank according to the prior art forms an insulating layer using a polymer foam, such as polyurethane foam (PUF), on the outer wall of the tank, which is made of an alloy resistant to low temperatures such as aluminum alloy, SUS (Steel Use Stainless), or 9% nickel alloy (9% Nickel steel), and is placed on a separate support structure provided at the bottom of the hull.

[0016] In the prior art, the insulation layer may be formed by applying a spray foam type insulation material to the outer wall of a tank multiple times at intervals using a device such as a spray gun, and the thickness is determined according to the type of insulation material or its insulation performance.

[0017] Injection-type standalone liquefied gas storage tanks offer advantages in terms of insulation performance and production costs, as they allow for the continuous construction of insulation layers on the tank's outer wall, facilitating work and minimizing thermal bridging. However, for cryogenic fluids with very low liquefaction points, such as LNG or liquid hydrogen (LH2), the tank may not be able to withstand thermal stress caused by extreme temperature differences, potentially leading to interface damage between the tank's outer wall and the insulation layer or detachment of the insulation layer from the wall.

[0018] Meanwhile, since a leak of liquefied gas from the outer wall of such an independent storage tank can cause fatal damage to the hull, which is vulnerable to cryogenic temperatures, it may have a partial secondary barrier structure to prevent the leaked liquefied gas from coming into contact with the hull and to safely collect or recover the leaked liquefied gas.

[0019] In other words, a drip tray is installed at the bottom of the storage tank to minimize direct impact to the hull in the event of a liquefied gas leak, and the size of the drip tray is designed by estimating the amount leaked over 15 days in accordance with the International Code for the construction and equipment of ships carrying liquefied gases in bulk (IGC code).

[0020] Here, a leak path must be provided between the tank outer wall and the insulation layer to allow leaked liquefied gas to flow into the drip tray by gravity; however, when the insulation layer is formed by applying spray foam insulation to the tank outer wall, the tank outer wall and the insulation layer adhere completely, making it difficult to form a leak path in the event of a liquefied gas leak.

[0021] The present invention aims to provide an insulation structure for a liquefied gas storage tank and a method for forming the insulation structure, wherein the insulation layer is provided in a non-bonding form rather than being directly bonded to the outer wall of the tank, and a separate insulation layer fixing device is provided to ensure the soundness of the insulation structure, while simultaneously forming a leakage path between the outer wall of the tank and the insulation layer to function as an auxiliary barrier when a liquefied gas leak occurs on the outer wall of the tank. means of solving the problem

[0022] According to one aspect of the present invention, an insulating structure for a liquefied gas storage tank for insulating liquefied gas stored inside a tank body may be provided, comprising: a composite layer installed to surround the tank body; an insulating portion formed by applying on the composite layer; and a fixing portion for fixing the composite layer to the tank body.

[0023] The above composite layer may be composed of a metal film capable of watertightness or airtightness and a glass fiber-based reinforcing sheet laminated together.

[0024] In addition, it may further include a flow path forming part installed between the tank body and the composite layer to form a leakage path.

[0025] Additionally, the above-mentioned Euro-forming portion may include a support plate formed on the bottom surface of the composite layer to support the composite layer; and a support pad that supports the support plate spaced apart from the outer surface of the tank body.

[0026] In addition, the stud formed on the outer surface of the tank body can penetrate the support pad, the support plate, and the composite layer in sequence.

[0027] In addition, the support plate and the support pad may be made of engineering plastic material.

[0028] In addition, the support pad forms a void space between the tank body and the support plate, and one or more grooves may be formed on the lower surface that contacts the tank body.

[0029] In addition, the grooves may be formed in two or more different directions on the lower surface of the support pad.

[0030] Additionally, the fixed member may include an extension member, one end of which is coupled to the stud; a nut member, which is coupled to the other end of the extension member; and a washer member, which is installed between the stud and one end of the extension member and between the other end of the extension member and the nut member, respectively.

[0031] In addition, it may further include a fixing block installed on the composite layer before forming the insulation portion.

[0032] In addition, the fixed block may be installed to surround the extension member by forming a through hole corresponding to the diameter of the extension member.

[0033] In addition, a recess may be formed in the upper and lower portions of the fixed block to provide a space for accommodating the washer member or the washer member and the nut member.

[0034] In addition, the extension member, the washer member, and the nut member may be made of engineering plastic material.

[0035] In addition, it may further include a reinforcing member installed within the insulation member to prevent the progression of cracks in the thickness direction of the insulation member.

[0036] In addition, the reinforcing member may include a first crack-prevention layer installed on the upper surface of the fixed block.

[0037] In addition, the insulation portion may include a first insulation layer, a second insulation layer, and a third insulation layer formed sequentially in a direction away from the outer surface of the tank body.

[0038] In addition, the first insulation layer is formed to have the same thickness as the fixing block, and the first crack prevention layer may be installed between the first insulation layer and the second insulation layer.

[0039] According to another aspect of the present invention, a method for forming an insulation structure of a liquefied gas storage tank for insulating liquefied gas stored inside a tank body is provided, comprising the steps of: installing a composite layer on the outer surface of the tank body to surround the tank body; and applying a spray foam insulation material onto the composite layer to form an insulation portion.

[0040] The above composite layer may be composed of a metal film capable of watertightness or airtightness and a glass fiber-based reinforcing sheet laminated together.

[0041] In addition, prior to the step of installing the composite layer, the method may further include the step of installing a flow path forming part between the tank body and the composite layer to form a leakage path for liquefied gas leaked on the outer surface of the tank body.

[0042] In addition, the above-mentioned Euro-forming part can be fixed to the tank body through a fixing part that is coupled to a stud formed on the outer surface of the tank body.

[0043] In addition, the above-mentioned Euro-forming part and the above-mentioned fixing part may be made of engineering plastic material. Effects of the invention

[0044] The present invention can minimize the penetration of liquefied gas leaking from the tank body into the insulation part by installing a composite layer capable of liquid-tight or water-tight between the tank body and the insulation part.

[0045] In addition, a leakage path for the movement of leaked liquefied gas can be secured through the empty space between the tank body and the support plate and the groove formed on the lower surface of the support pad.

[0046] In addition, since the support plate and base pad constituting the Euro-forming part are made of engineering plastic material, the risk of damage caused by the difference in thermal shrinkage between the interface of the tank body and the insulation part can be avoided, and it can be effective for the rapid detection and discharge of leaked liquefied gas.

[0047] In addition, by installing a fixing block on the composite layer, spray foam insulation can be adhered to the outer surface of the fixing block during the insulation formation process, thereby improving the fixing strength of the insulation.

[0048] In addition, before forming the insulation section, a fixing block is installed on the composite layer to improve the fixing strength of the insulation section. By tightly fixing the composite layer and the fixing block to the tank body through an extension member connected to a stud and a washer member and a nut member connected to the extension member, the soundness of the insulation structure can be ensured.

[0049] In addition, the extension member, washer member, and nut member constituting the fixed part are made of engineering plastic material, so they can have a relatively lower thermal conductivity compared to SUS, and can have the advantageous effect of securing stable fixing force while minimizing heat loss.

[0050] In addition, direct contact between the insulation and the fixing part can be blocked through the recess structure formed on the upper and lower parts of the fixing block and the reinforcing part placed on the upper surface of the fixing block, and the risk of damage to the insulation material caused by the fixing part can be avoided. Brief explanation of the drawing

[0051] FIG. 1 is a schematic diagram illustrating a portion of the cross-section of an insulation structure of a liquefied gas storage tank according to one embodiment of the present invention. Figure 2 is a diagram showing the configuration of the Euro-forming part illustrated in Figure 1, separated and displayed individually. Figure 3 is a drawing showing the configuration of the fixed part illustrated in Figure 1. Figure 4 is a perspective view of the fixed block illustrated in Figure 1. Specific details for implementing the invention

[0052] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0053] First, it should be noted that when adding reference numerals to the components of each drawing, the same components are to have the same numeral whenever possible, even if they are shown on different drawings.

[0054] In addition, in describing the present invention, if it is determined that a detailed description of related known components or functions may obscure the essence of the invention, such detailed description is omitted.

[0055] Preferred embodiments of the present invention will be described below, but the technical concept of the present invention is not limited thereto and can be modified and implemented in various ways by those skilled in the art.

[0056] In describing the present invention, liquefied gas may include all gaseous fuels generally stored in a liquefied state, such as LNG (Liquefied Natural Gas) at cryogenic temperatures (approximately -163°C), LPG (Liquefied Petroleum Gas), or liquefied ethylene gas, and the term liquefied gas may include not only liquefied gas in a liquid state but also vaporized liquefied gas.

[0057] FIG. 1 is a schematic diagram showing a portion of the cross-section of an insulation structure of a liquefied gas storage tank according to one embodiment of the present invention, FIG. 2 and FIG. 3 are diagrams showing the configuration of the flow path forming part and the fixing part shown in FIG. 1 separately, respectively, and FIG. 4 is a perspective view of the fixing block shown in FIG. 1.

[0058] The present invention relates to an insulation structure (100) of a liquefied gas storage tank for insulating liquefied gas stored inside a tank body (10), and can be applied to an independent liquefied gas storage tank that is manufactured to be mounted on a hull separately from the structure of the hull, and preferably can be applied to a Type B independent liquefied gas storage tank that includes an insulation layer installed to surround the outside of the tank body (10) which performs the function of a primary barrier, and a drip tray that temporarily stores liquefied gas leaked from the bottom of the tank body (10).

[0059] Here, the tank body (10) can be manufactured from an alloy that is resistant to low temperatures, such as aluminum alloy, SUS (Steel Use Stainless), or 9% nickel alloy (9% Nickel steel), and preferably, it can be made of high-manganese steel, which is inexpensive and has excellent brittle resistance at low temperatures, so it can withstand ultra-low temperatures.

[0060] Referring to FIG. 1, an insulating structure (100) of a liquefied gas storage tank according to one embodiment of the present invention is for insulating liquefied gas stored inside a tank body (1), and may include a composite layer (110) installed to surround the tank body (10), an insulating part (130) formed by coating on the composite layer (110), and a fixing part (150) for fixing the composite layer (110) to the outer surface of the tank body (10).

[0061] The composite layer (110) is installed to surround the tank body (10), and can be fixed to the outside of the tank body (10) through a fixing part (150) described later by inserting a stud (11) formed on the outer surface of the tank body (10) through it.

[0062] In this embodiment, the stud (11) is installed vertically on the outer surface of the tank body (10) via welding or the like before installing the composite layer (110), and can be made of the same material as the tank body (10).

[0063] In the composite layer (110) of the present embodiment, a through hole (not shown) having a size equal to or similar to the diameter of a stud (11) may be pre-formed, and the stud (11) may be formed to protrude through the composite layer (110).

[0064] Additionally, although not illustrated in detail in the drawing, the composite layer (110) of the present embodiment may be composed of a metal film capable of liquid tight or air tight, such as an aluminum film, and a glass fiber-based reinforcing sheet laminated on the outside of the tank body (10).

[0065] In this embodiment, the metal film may be made of a metal material resistant to low-temperature brittleness, such as aluminum, and may have watertight or airtight properties in the area excluding the part where the stud (11) is inserted through, thereby minimizing the penetration of leaked liquefied gas into the insulation part (130).

[0066] The composite layer (110) can improve adhesion with the spray foam insulation material forming the insulation part (130) and reduce the possibility of cracks occurring in the insulation part (130) in a cryogenic environment by placing (or laminating) a glass fiber-based reinforcing sheet on the upper surface of the metal film, more specifically on the surface facing the insulation part (130).

[0067] The composite layer (110) of the present embodiment may be provided in the form of a single large sheet to cover the entire outer surface of the tank body (10), but may also be divided into a plurality of unit sheets to improve ease of installation and installed so as to be in close contact with each other on the outer surface of the tank body (10).

[0068] An insulation structure (100) of a liquefied gas storage tank according to one embodiment of the present invention can minimize the penetration of liquefied gas leaking from the tank body (10) into the insulation part (130) by installing a composite layer (110) capable of liquid-tight or water-tight between the tank body (10) and the insulation part (130).

[0069] In this embodiment, it is obvious that the composite layer (110) may be configured by stacking a metal film and a reinforcing sheet in three or four layers or more as needed.

[0070] The insulation structure (100) of a liquefied gas storage tank according to one embodiment of the present invention may further include a flow path forming part (120) installed between the tank body (10) and the composite layer (110) to form a leakage path, as shown in FIG. 1.

[0071] An insulation structure (100) of a liquefied gas storage tank according to one embodiment of the present invention aims to minimize the penetration of liquefied gas leaking from the tank body (10) into the insulation part (130) through a composite layer (110) installed between the tank body (10) and the insulation part (130), and to provide a path for the movement of the leaked liquefied gas.

[0072] The Euro forming part (120) may include a support plate (121) formed on the bottom surface of the composite layer (110) to support the composite layer (110), and a support pad (123) that supports the support plate (121) spaced apart from the outer surface of the tank body (10).

[0073] The support plate (121) is installed to surround the tank body (10) between the tank body (10) and the composite layer (110), and can be spaced apart from the outer surface of the tank body (10) on a support pad (123) having a predetermined size.

[0074] The support plate (121) of the present embodiment may be provided in the form of a single large sheet to cover the entire outer surface of the tank body (10), similar to the composite layer (110), but may also be divided into a plurality of unit sheets and installed so as to be in close contact with each other on the outer surface of the tank body (10), as shown in FIG. 2 (a).

[0075] The support pad (123) is intended to maintain a constant distance between the tank body (10) and the support plate (121), and can form a void space (not indicated) between the tank body (10) and the support plate (121).

[0076] In the present embodiment, the support pad (123) may have a through hole (123a) formed in the central part for a stud (11) formed on the outer surface of the tank body (10) to pass through, and one or more grooves (123b) may be formed on the lower surface that contacts the tank body (10).

[0077] Referring to FIG. 2(b), the support pad (123) of the present embodiment is shown having a rectangular planar shape and two grooves (123b) formed in mutually orthogonal directions on the lower surface of the support pad (123), but the present invention is not limited thereto, and the support pad (123) of the present embodiment may have various shapes such as a circle or a polygon.

[0078] Additionally, the number of grooves (123b) formed on the lower surface of the support pad (123) can be varied by taking into account the shape (or size) of the support pad (123) and the amount of leaking liquefied gas, and it may be preferable to form two or more grooves in different directions on the lower surface of the support pad (123).

[0079] In this embodiment, the shape of the groove (123b) of the support pad (123) is not particularly limited as long as it allows for a smooth flow of leaked liquefied gas, but it may be preferable to have a semicircular or elliptical cross-sectional shape.

[0080] The Euro-forming part (120) of the present embodiment can be fixed by combining a stud (11), which penetrates the support pad (123), the support plate (121), and the composite layer (110) in sequence, with a fixing part (150) described later.

[0081] An insulation structure (100) of a liquefied gas storage tank according to one embodiment of the present invention can secure a leak path for the movement of leaked liquefied gas through the empty space between the tank body (10) and the support plate (121) and the groove (123b) formed on the lower surface of the support pad (123).

[0082] In this embodiment, the support plate (121) and the support pad (123) constituting the Euro forming part (120) may be made of engineering plastic (EP) material.

[0083] To elaborate, engineering plastics (EP) are distinguished from common plastics such as polyethylene and polypropylene; they possess excellent strength and elasticity, allowing them to withstand extreme temperature conditions without easily deforming or being damaged.

[0084] In this embodiment, the operating temperature of the engineering plastic (EP) is from room temperature to cryogenic temperatures of -163°C or lower.

[0085] The Euro-forming part (120) of the present embodiment may not be made of a material that does not have additional reinforcement such as glass fiber or carbon, such as non-polar PTFE (Polytetrafluoroethylene), and the polarity of the engineering plastic (EP) may not be taken into consideration.

[0086] In one embodiment of the present invention, the insulation structure (100) of a liquefied gas storage tank is provided with a flow path forming section (120) for the movement of leaked liquefied gas between the outer surface of the tank body (10) and the composite layer (110), wherein the support plate (121) and the support pad (123) constituting the flow path forming section (120) are made of engineering plastic (EP) material, thereby avoiding the risk of damage caused by the difference in thermal shrinkage between the interface of the tank body (10) and the insulation section (130), and thus being effective for the rapid detection and discharge of leaked liquefied gas.

[0087] The insulation section (130) can be formed by applying spray foam insulation material onto the composite layer (110), and can have a thickness that ensures sufficient insulation performance by considering the size of the tank body (10) or the type or density of the insulation material applied onto the composite layer (110).

[0088] The insulation part (130) of the present embodiment may form one or more layers to store liquefied gas stored inside the tank body (10).

[0089] Hereinafter, for convenience of explanation, the insulation section (130) of the present embodiment is described as an example in which an insulating material is sprayed and laminated multiple times on a composite layer (110) to form three layers, and is divided into a first insulating layer (131), a second insulating layer (133), and a third insulating layer (135) in a direction away from the outer surface of the tank body (10).

[0090] In other words, the insulation section (130) of the present embodiment may be composed of three layers, with a first insulation layer (131), a second insulation layer (133), and a third insulation layer (133) installed sequentially on the composite layer (110).

[0091] In the present embodiment, the first to third insulation layers (131, 133, 135) may be formed by spraying and laminating multiple times an insulating material having the same material and density, or at least one of the first to third insulation layers (131, 133, 135) may be formed with the same material but with a density different from the others.

[0092] In addition, when the first to third insulation layers (131, 133, 135) are applied with different densities, it may be desirable to form a higher density the closer they are to the tank body (10), and it may be desirable to form a thinner thickness the higher the density.

[0093] Meanwhile, a composite layer (110) and a flow path forming part (120) are installed between the tank body (10) and the insulation part (130) to relieve stress caused by the difference in thermal expansion coefficients between the tank body (10) and the insulation part (130), but since the insulation part (130) may be separated from the composite layer (110) in a cryogenic environment, it is necessary to fix the insulation part (130) to the tank body (10).

[0094] An insulation structure (100) of a liquefied gas storage tank according to one embodiment of the present invention may further include a fixing block (140) installed on a composite layer (110) before forming an insulation portion (130).

[0095] The fixing block (140) is intended to improve the fixing strength of the insulation part (130) by having spray foam insulation material adhere to the outer surface of the fixing block (140) during the process of forming the insulation part (130). It is made of polyurethane foam and can be fixedly installed on the composite layer (110) by the fixing part (150) before forming the insulation part (130).

[0096] Hereinafter, in describing the insulation structure (100) of the present embodiment, the configuration of the fixing part (150) will be described first, and the fixing block (140) will be described later.

[0097] The fixing part (150) may include an extension member (151) having one end connected to a stud (11) to fix the composite layer (110) and the other end extending outwardly toward the tank body (10), and a washer member (153) fitted onto the outer circumference of the end of the stud (11) or the extension member (151).

[0098] The extension member (151) may have a diameter larger than that of the stud (11) to accommodate the end of the stud (11) protruding on the composite layer (110), and a screw groove (151a) (see (a) in FIG. 3) may be formed on the inner surface of one end corresponding to the screw thread (not shown) formed on the outer surface of the stud (11).

[0099] The washer member (153) can be fitted into the stud (11) so as to be positioned on the composite layer (110) before the extension member (151) is attached to the outer surface of the stud (11), and can be positioned between the stud (11) and the extension member (151).

[0100] In this embodiment, an insertion hole (153a) (see (b) of FIG. 3) corresponding to the end diameter of the stud (11) may be formed in the central part of the washer member (153).

[0101] The washer member (153) of the present embodiment is formed to have an inner diameter equal to or larger than the outer diameter of the stud (11), but it may be preferable for the inner diameter to be smaller than the diameter of one end of the extension member (151).

[0102] That is, the fixing part (150) of the present embodiment is structured such that one end of an extension member (151), which is screw-coupled to the outer surface of a stud (11) at the upper part of a washer member (153) located on the composite layer (110), presses against the washer member (153), and the position of the composite layer (110) can be fixed through a simple screw coupling method.

[0103] Meanwhile, the fixing part (150) of the present embodiment may further include a nut member (155) that is coupled to a thread (151b) (see (a) of FIG. 3) formed on the outer surface of the other end of the extension member (151).

[0104] In this embodiment, the other end of the extension member (151) may have a diameter equal to or similar to that of the end of the stud (11), and a washer member (153) may be fitted onto the outer surface of the other end of the extension member (151) before the nut member (155) is attached.

[0105] The fixing block (140) of the present embodiment may have a through hole (140a) (see FIG. 4) formed in the center, as shown in FIG. 4, and may be installed to surround the extension member (151) screwed to the outer surface of the stud (11).

[0106] Additionally, the fixing block (140) of the present embodiment can be tightly fixed on the composite layer (110) by a nut member (155) that is fastened to the outer surface of the other end of the extension member (151) while installed to surround the extension member (151).

[0107] In this embodiment, a fastening hole (155a) (see (c) in FIG. 3) corresponding to the thread (151b) formed on the outer surface of the other end of the extension member (151) may be formed on the inner surface of the nut member (155), and it is natural that a washer member (153) is fitted on the outer surface of the other end of the extension member (151) before the nut member (155) is coupled.

[0108] That is, the fixing part (150) of the present embodiment can act as an anchor to fix the composite layer (110) and the flow path forming part (120) to the tank body (10) through an extension member (151) and a washer member (153) that are fastened to the stud (11), and to fix the fixing block (140) through a washer member (153) and a nut member (155) that are coupled to the other end of the extension member (151) and prevent the insulation part (130) from coming off.

[0109] In this embodiment, a recess (see reference numeral '141' in FIG. 4) may be formed in the upper and lower parts of the fixing block (140) to provide a space for fastening a washer member (153) and a nut member (155).

[0110] In one embodiment of the present invention, the insulation structure (100) of a liquefied gas storage tank can have the effect of ensuring the soundness of the insulation structure by installing a fixing block (140) on a composite layer (110) to improve the fixing force of the insulation part (130) before forming the insulation part (130), and by tightly fixing the composite layer (110) and the fixing block (140) to the tank body (10) through an extension member (151) coupled to a stud (11) and a washer member (153) and a nut member (155) fastened to the extension member (151).

[0111] In this embodiment, the extension member (151), washer member (153), and nut member (155) constituting the fixing part (150) may preferably be made of engineering plastic (EP) material, just like the flow path forming part (120).

[0112] The fixing part (150) of this material can have a relatively low thermal conductivity compared to SUS and can have the advantageous effect of securing stable fixing power while minimizing heat loss.

[0113] Meanwhile, if a leak of liquefied gas occurs on the outer surface of the tank body (10), even if a leakage path is formed between the tank body (10) and the insulation part (130), the insulation material constituting the insulation part (130) may shrink or expand due to the increase in pressure between the tank body (10) and the insulation part (130), causing a crack to occur or progress.

[0114] An insulation structure (100) of a liquefied gas storage tank according to one embodiment of the present invention may further include a reinforcing member (170) installed within an insulation member (130).

[0115] The reinforcing member (170) may be provided in the form of a mesh made of glass fiber or SUS material and may act as a crack arrester to prevent the progression of cracks in the thickness direction of the insulation member (130).

[0116] The reinforcing part (170) of this embodiment can serve to prevent the insulation part (130) from detaching due to pressure rise caused by leakage of liquefied gas in a cryogenic environment or external impact.

[0117] In this embodiment, the reinforcing member (170) may essentially be placed on the upper surface of the fixed block (140), and it may be preferable to place one or more depending on the thickness of the insulation member (130).

[0118] In one embodiment of the present invention, the insulation structure (100) of a liquefied gas storage tank can block direct contact between the insulation part (130) and the fixing part (150) through a recess structure formed on the upper and lower parts of the fixing block (140) and a reinforcing part (170) disposed on the upper surface of the fixing block (140), and can avoid the risk of damage to the spray foam insulation material caused by the fixing part (150).

[0119] In this embodiment, the first insulating layer (131) formed by being initially applied on the composite layer (110) may preferably be formed to have a thickness equal to or similar to that of the fixing block (140).

[0120] Referring to FIG. 1, the reinforcing member (170) of the present embodiment is shown having a first crack-preventing layer (171) installed between the upper surface of the fixing block (140) and the first insulation layer (131) and the second insulation layer (133), and a second crack-preventing layer (173) installed between the second insulation layer (133) and the third insulation layer (135).

[0121] Meanwhile, the insulation structure (100) of a liquefied gas storage tank according to one embodiment of the present invention may further include an external coating layer (190) formed on the insulation part (130) to prevent damage to the insulation part (130) caused by moisture, contamination, or impact from the outside.

[0122] The outer coating layer (190) can be formed on the outer surface of the insulation part (130) through any one of the following methods: polyurea coating, metal cladding, or fiber reinforced plastic coating. In addition, various other methods can be applied as long as they are configured to block moisture entering from the outside and prevent damage caused by external forces.

[0123] An insulation structure (100) of a liquefied gas storage tank according to one embodiment of the present invention can minimize the penetration of liquefied gas leaking from the tank body (10) into the insulation part (130) by installing a composite layer (110) capable of liquid-tight or water-tight between the tank body (10) and the insulation part (130).

[0124] In addition, a leakage path for the movement of leaked liquefied gas can be secured through the empty space between the tank body (10) and the support plate (121) and the groove (123b) formed on the lower surface of the support pad (123).

[0125] In addition, the support plate (121) and the support pad (123) constituting the Euro forming part (120) are made of engineering plastic (EP) material, thereby avoiding the risk of damage caused by the difference in thermal shrinkage between the interface of the tank body (10) and the insulation part (130), and can be effective for the rapid detection and discharge of leaked liquefied gas.

[0126] In addition, a fixing block (140) is installed on the composite layer (110) so that spray foam insulation is adhered to the outer surface of the fixing block (140) during the process of forming the insulation part (130), thereby improving the fixing strength of the insulation part (130).

[0127] In addition, a fixing block (140) is installed on the composite layer (110) to improve the fixing force of the insulation part (130) before forming the insulation part (130). By using an extension member (151) coupled to the stud (11) and a washer member (153) and a nut member (155) fastened to the extension member (151), the insulation part (110) and the fixing block (140) are tightly fixed to the tank body (10), thereby ensuring the soundness of the insulation structure.

[0128] In addition, the extension member (151), washer member (153), and nut member (155) constituting the fixing part (150) are made of engineering plastic (EP) material, so they can have a relatively lower thermal conductivity compared to SUS, and can have the advantageous effect of securing stable fixing force while minimizing heat loss.

[0129] In addition, direct contact between the insulation part (130) and the fixing part (150) can be blocked through the recess structure formed on the upper and lower parts of the fixing block (140) and the reinforcing part (170) disposed on the upper surface of the fixing block (140), and the risk of damage to the insulation material caused by the fixing part (150) can be avoided.

[0130] The thermal insulation structure (100) of the liquefied gas storage tank according to the present invention can be applied to any marine structure used while floating in the sea where flow occurs, and can be applied to all offshore plants such as LNG FPSO (Floating, Production, Storage and Offloading) or LNG FSRU (Floating Storage and Regasification Unit), including ships such as liquefied gas carriers or LNG RVs (LNG Regasification Vessels) that transport LNG or LPG.

[0131] The above description is merely an illustrative explanation of the technical concept of the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications, changes, and substitutions within the scope of the essential characteristics of the present invention without departing from its nature.

[0132] The embodiments disclosed in this invention and the accompanying drawings are intended to explain, not limit, the technical concept of the invention, and the scope of the technical concept of the invention is not limited by these embodiments and accompanying drawings.

[0133] Furthermore, the scope of protection of the present invention shall be interpreted by the claims below, and all technical ideas within an equivalent scope shall be interpreted as being included within the scope of rights of the present invention. Explanation of the symbols

[0134] 10: Tank body 11: Stud 100: Insulated structure 110: Composite layer 120: Euro-forming part 121: Supporting plate 123: Supporting pad 130: Insulation section 131: First insulation layer 133: Second insulation layer 135: Third insulation layer 140: Fixed block 150: Fixed part 151: Extender 153: Washer member 155: Nut member 170: Reinforcement (Crack arrester) 171: 1st crack-prevention layer 173: Second crack-prevention layer 190: External coating layer

Claims

Claim 1 An insulation structure for a liquefied gas storage tank for insulating liquefied gas stored inside a tank body, comprising: a composite layer installed to surround the tank body; an insulation portion formed by applying a spray foam insulation material on the composite layer; and a fixing portion for fixing the composite layer to the tank body, wherein the composite layer comprises a metal film capable of watertightness or airtightness and a glass fiber-based reinforcing sheet laminated thereon, and prior to forming the insulation portion, a fixing block having a recessed structure on its upper and lower surfaces and a reinforcing portion installed on the upper surface of the fixing block. Claim 2 In claim 1, an insulation structure of a liquefied gas storage tank further comprising a flow path forming part installed between the tank body and the composite layer to form a leakage path. Claim 3 In claim 2, the above-mentioned Euro-forming portion comprises: a support plate formed on the bottom surface of the composite layer to support the composite layer; and a support pad that supports the support plate spaced apart from the outer surface of the tank body, forming an insulation structure of a liquefied gas storage tank. Claim 4 In claim 3, the stud formed on the outer surface of the tank body penetrates the support pad, the support plate, and the composite layer in sequence, forming an insulation structure of a liquefied gas storage tank. Claim 5 In Clause 3, the insulation structure of a liquefied gas storage tank, wherein the support plate and the support pad are made of engineering plastic material. Claim 6 In claim 3, the insulation structure of a liquefied gas storage tank wherein the support pad forms a void space between the tank body and the support plate, and one or more grooves are formed on the lower surface in contact with the tank body. Claim 7 In claim 6, the above grooves are an insulating structure of a liquefied gas storage tank formed in two or more different directions on the lower surface of the support pad. Claim 8 In claim 4, the fixing member comprises: an extension member having one end connected to the stud; a nut member connected to the other end of the extension member; and a washer member installed between the stud and one end of the extension member and between the other end of the extension member and the nut member, respectively, in an insulating structure of a liquefied gas storage tank. Claim 9 In claim 8, the above-mentioned fixed block is an insulating structure of a liquefied gas storage tank installed to surround the extension member, with a through hole formed to correspond to the diameter of the extension member. Claim 10 In claim 9, an insulating structure of a liquefied gas storage tank, wherein a concave groove is formed in the upper and lower portions of the fixed block to provide a space for accommodating the washer member or the washer member and the nut member. Claim 11 In claim 8, the extension member, the washer member, and the nut member are an insulating structure of a liquefied gas storage tank made of engineering plastic material. Claim 12 delete Claim 13 In claim 1, the insulation section comprises a first insulation layer, a second insulation layer, and a third insulation layer formed sequentially in a direction away from the outer surface of the tank body, wherein the first insulation layer is formed to have the same thickness as the fixing block, and a first crack-preventing layer, which is a reinforcing material, is installed between the first insulation layer and the second insulation layer, in an insulation structure of a liquefied gas storage tank. Claim 14 A method for forming an insulating structure of a liquefied gas storage tank according to claim 1 for insulating liquefied gas stored inside a tank body, comprising: a step of installing a composite layer on the outer surface of the tank body to surround the tank body; and a step of forming an insulating portion by applying a spray foam insulating material on the composite layer, wherein the composite layer is composed of a metal film capable of watertightness or airtightness and a glass fiber-based reinforcing sheet laminated thereon. Claim 15 A method for forming an insulating structure of a liquefied gas storage tank according to claim 14, further comprising the step of installing a flow path forming part between the tank body and the composite layer to form a leakage path for liquefied gas leaked on the outer surface of the tank body prior to the step of installing the composite layer. Claim 16 In claim 15, the above-mentioned flow path forming part is fixed to the tank body through a fixing part coupled to a stud formed on the outer surface of the tank body, and the above-mentioned flow path forming part and the above-mentioned fixing part are made of engineering plastic material, a method for forming an insulating structure of a liquefied gas storage tank.

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