Liquefied gas storage tank, and method for manufacturing liquefied gas storage tank

Abstract

The present invention relates to a liquefied gas storage tank and, more specifically, to a liquefied gas storage tank and a manufacturing method therefor, the storage tank comprising a vacuum insulation structure between an inner tank and an outer tank so as to store cryogenic liquefied gas. The liquefied gas storage tank according to the present invention comprises: an inner tank for accommodating liquefied gas; an outer tank spaced at a gap from the outside of the inner tank, and disposed to surround the circumference of the inner tank; a vacuum insulation space which is a space formed between the inner tank and the outer tank, and which blocks convection heat transfer in a vacuum state; and an adhesive insulation material which is a composite material applied and adhered to the outer surface of the inner tank, and which is for blocking radiant heat energy transmitted to the inner tank.

Description

Liquefied gas storage tank and method of manufacturing a liquefied gas storage tank

[0001] The present invention relates to a liquefied gas storage tank, and more specifically, to a liquefied gas storage tank that stores cryogenic liquefied gas by including a vacuum insulation structure between an inner tank and an outer tank, and a method for manufacturing the same.

[0002] As global warming intensifies, efforts to reduce greenhouse gas emissions are being made worldwide.

[0003] Natural gas is one of the eco-friendly fuels that emits fewer air pollutants during combustion because it can remove or reduce air pollutants during the liquefaction process, and its consumption is rapidly increasing worldwide.

[0004] Meanwhile, because hydrogen is environmentally friendly and has high energy density, it can be utilized as a power source for automobiles and as fuel for fuel cells in portable electronic devices. Furthermore, as the price of hydrogen-fueled fuel cells decreases every year, the demand for hydrogen is increasing annually.

[0005] Environmentally friendly gaseous fuels, such as natural gas and hydrogen gas, have low volumetric density, resulting in poor transportation efficiency when transported in a gaseous state. To compensate for this, a method of storing the fuels in the form of liquefied gas and transporting them to their destination by carriers is primarily used.

[0006] Liquefied natural gas (LNG), obtained by liquefying natural gas, has a boiling point of approximately -163°C at atmospheric pressure and its volume decreases to about 1 / 600 of its volume in the natural gas state. Additionally, hydrogen has a boiling point of approximately -253°C at atmospheric pressure and its volume decreases to about 1 / 865 of its volume in the gaseous state.

[0007] Storing eco-friendly gas fuel in the form of liquefied gas allows for high-density storage compared to storing it in a gaseous state, which is advantageous not only in terms of safety but also has the advantage of a low risk of explosion.

[0008] Membrane-type tanks or independent-type tanks can be primarily used to store cryogenic liquefied gas. Independent-type tanks can be classified into Type C tanks, referred to as pressure vessels, and Type A and Type B tanks, which are atmospheric tanks.

[0009] In addition, since cryogenic liquefied gases such as LNG and liquefied hydrogen have vapor pressures higher than atmospheric pressure and boiling points at extremely low temperatures, cryogenic liquefied gas storage tanks must be constructed from materials capable of withstanding cryogenic temperatures and being resistant to thermal stress and thermal shrinkage, and must be insulated to minimize heat intrusion.

[0010] In particular, since the temperature at which hydrogen exists in a liquid state (boiling point) is -253°C at atmospheric pressure and -242°C or lower in a pressurized environment of 10 barg, the temperature difference with the external temperature of the storage tank, i.e., room temperature, reaches about 300°C. This temperature difference becomes a factor in heat transfer, and heat intrusion caused by the heat flux resulting from heat transfer causes the evaporation of the liquid hydrogen stored inside.

[0011] The evaporated gas generated inside the storage tank ultimately represents the loss of liquefied gas during the storage and transportation process. Therefore, to minimize transportation losses by reducing the Boil-Off Rate (BOR) of liquefied gas, measures must be taken to improve the insulation performance of the storage tanks where the gas is stored or to reduce heat loss.

[0012] Although standalone pressurized tanks are designed to withstand pressure increases caused by the generation of evaporated gas within the maximum allowable pressure, they need to be managed by enhancing insulation performance to prevent reaching the critical point.

[0013] In order to maintain a cryogenic state for a long period, heat inflow into the liquefied gas storage tank from the outside must be minimized, and ultimately, the core objective of the insulation structure of the liquefied gas storage tank is to minimize the three elements of heat transfer, such as convection, conduction, and radiation.

[0014] Referring to FIG. 1, the existing standalone pressurized tank is equipped with a double insulation structure including an inner tank (1) and an outer tank (2) to withstand cryogenic temperatures and high pressures. The cross-section of the inner tank (1) that contains liquefied gas is circular or elliptical.

[0015] Additionally, powdered insulating material (5) is filled into the annular space (3) between the inner tank (1) and the outer tank (2) and vacuumed. Since the annular space (3) is in a vacuum state, convective heat transfer from the outside to the inner tank (1) is blocked, and radiative heat transfer is blocked by the powdered insulating material (5) filled in the annular space (3).

[0016] However, there is thermal energy conducted through the insulation material (5) filled in the annular space (3), and thermal energy from the outside is transferred to the inner tank (1), which becomes a factor in increasing the temperature of the inner tank (1).

[0017] Meanwhile, the powdered insulation material (5) is introduced through the insulation material supply unit (7) provided at the top of the storage tank (T). As the powdered insulation material (5) is injected into the annular space (3) through the insulation material supply unit (7), an angle of repose is created according to the deposition characteristics of the powder, and accordingly, an empty space (6) that is not filled with the powdered insulation material (5) is created.

[0018] Additionally, during the storage and transport of liquefied gas, the inner tank (1) undergoes thermal contraction due to the cryogenic temperature of the liquefied gas, causing the volume of the annular space (3) to increase compared to when the powdered insulation material (5) was filled before storing the liquefied gas.

[0019] When the volume of the annular space (3) increases, the powdered insulation material (5) filled in the upper part sinks into the expanded annular space (3) in the lower part due to the influence of the self-weight of the insulation material, the movement of the ship such as rolling or pitching. Due to the sinking of the powder, the volume occupied by the empty space (6) in the upper part becomes larger, and if there are many empty spaces (6) that are not filled with insulation material (5), radiant heat transfer is not blocked to that extent.

[0020] Therefore, the existing double insulation structure cannot block conductive heat transfer by the powdered insulation material (5) filled in the annular space (3), and since there is an area where radiative heat transfer is not blocked by the empty space (6), the insulation performance is bound to deteriorate while storing liquefied gas.

[0021] The present invention aims to solve the aforementioned problems by applying a double insulation structure to the liquefied gas storage tank, thereby preventing the rise in internal temperature due to conductive and radiative heat transfer, and by providing a method for manufacturing the liquefied gas storage tank.

[0022] The technical problems of the present invention are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art from the description below.

[0023] According to one aspect of the present invention for achieving the above-described purpose, a liquefied gas storage tank is provided, comprising: an inner tank for receiving liquefied gas; an outer tank spaced apart from the outer side of the inner tank and arranged to surround the perimeter of the inner tank; a vacuum insulation space formed between the inner tank and the outer tank to block convective heat transfer in a vacuum state; and an adhesive insulation material, which is a composite material applied to the outer surface of the inner tank and adhered thereto to block thermal radiation energy transferred to the inner tank.

[0024] Preferably, the adhesive insulation material may be a cryogenic composite material in which a thermal radiation blocking material capable of blocking thermal radiation energy and an ultra-cold-resistant cryogenic material capable of withstanding a cryogenic environment and having adhesive properties are mixed.

[0025] Preferably, the adhesive insulation material comprises one or more selected from a group of materials for blocking thermal radiation, including glass bubbles, hollow glass microspheres, and aluminum, and may further comprise one or more selected from a group including epoxy, polyimide, polyurethane, and silicone.

[0026] Preferably, the adhesive insulation material is in a semi-solid state when applied to the outer surface of the inner tank, and when liquefied gas is stored in the inner tank and transported, the semi-solid state hardens and can be maintained in a state of adhesion to the outer surface of the inner tank with a thickness greater than or equal to a preset thickness.

[0027] According to another aspect of the present invention for achieving the above-mentioned purpose, a method for manufacturing a liquefied gas storage tank is provided, comprising: a step of forming an adhesive insulation material on the outer surface of an inner tank receiving liquefied gas; a step of lowering the vacuum level of a vacuum insulation space formed between the inner tank and the outer tank to separate the inner tank and the outer tank; and a loading step of storing liquefied gas in the inner tank.

[0028] Preferably, the adhesive insulation forming step may include an insulation manufacturing step for manufacturing a composite material in a semi-solid state, an insulation coating step for applying the composite material in a semi-solid state to the outer surface of the inner tank, and an insulation bonding step for curing the composite material in a semi-solid state applied to the outer surface of the inner tank.

[0029] Preferably, the insulation material application step may involve applying a semi-solid composite material to a certain thickness using a spray gun or a roller.

[0030] Preferably, the adhesive insulation material may be a composite material mixed with one or more selected from a group of materials for blocking thermal radiation including glass bubbles, hollow glass microspheres, and aluminum, and one or more selected from a group including epoxy, polyimide, polyurethane, and silicone.

[0031] Preferably, in the vacuuming step, the vacuum insulation space is depressurized by operating a vacuum pump or opening a gas discharge port until the internal pressure of the vacuum insulation space becomes negative pressure, and this step can be performed when the vacuum insulation space is empty and the application and adhesion of the adhesive insulation material to the outer surface of the inner tank is completed.

[0032] According to another aspect of the present invention for achieving the above-described purpose, an inner tank for receiving liquefied gas; an outer tank spaced apart from the outer side of the inner tank and arranged to surround the perimeter of the inner tank; and a vacuum insulation space formed between the inner tank and the outer tank, which blocks convective heat transfer in a vacuum state; A liquefied gas storage tank having a double insulation structure is provided, comprising: an adhesive insulation material provided on the outer surface of the inner tank to block thermal radiation energy transmitted to the inner tank; wherein the vacuum insulation space does not contain molecules capable of causing heat conduction or heat convection, and the adhesive insulation material is a mixture of a thermal radiation blocking material and a cryogenic material having adhesive properties in a cryogenic state, mixed at a ratio that prevents delamination due to a difference in thermal expansion coefficients with the inner tank, and is applied in a semi-solid state to the outer surface of the inner tank and maintained in an adhesive state with a thickness greater than or equal to a preset thickness, wherein the thermal radiation blocking material comprises one or more of glass bubbles or aluminum powder, and the cryogenic material comprises one or more selected from the group including epoxy, polyimide, and silicone.

[0033] According to another aspect of the present invention for achieving the above-described purpose, an inner tank for receiving liquefied gas; an outer tank spaced apart from the outer side of the inner tank and arranged to surround the perimeter of the inner tank; and a vacuum insulation space formed between the inner tank and the outer tank; A method for manufacturing a liquefied gas storage tank having a double insulation structure, comprising: an adhesive insulation material provided on the outer surface of the inner tank to block thermal radiation energy transmitted to the inner tank; the method comprising: an insulation material manufacturing step of preparing a semi-solid mixture by mixing a thermal radiation blocking material and a cryogenic material, which is a material having adhesive properties in a cryogenic state, at a mixing ratio that prevents delamination due to a difference in the coefficient of thermal expansion with the inner tank; an adhesive insulation material forming step of providing an adhesive insulation material by applying the semi-solid mixture to the outer surface of the inner tank so that an adhesive state is maintained at a thickness greater than or equal to a preset thickness; a vacuuming step of creating a vacuum in a vacuum in a vacuum in a vacuum in a vacuum in a vacuum insulation space between the inner tank and the outer tank; and a loading step of storing liquefied gas in the inner tank, wherein the vacuum insulation space does not contain molecules capable of causing heat conduction or heat convection, the thermal radiation blocking material comprises one or more of glass bubbles or aluminum powder, and the cryogenic material comprises one or more selected from the group including epoxy, polyimide, and silicone. A method for manufacturing a liquefied gas storage tank is provided.

[0034] According to the liquefied gas storage tank and the method for manufacturing the same according to the present invention, by providing a vacuum insulation space and an adhesive insulation material, convective heat transfer and radiative heat transfer from the outside to the inner tank can be blocked.

[0035] In addition, regarding storage tanks capable of storing and transporting cryogenic or ultra-cryogenic liquefied gases with low boiling points, conventionally, filling the vacuum insulation space with insulation material resulted in a problem where insulation performance deteriorated due to shrinkage or subsidence of the inner tank; however, according to the present invention, by adhering insulation material to the outer surface of the inner tank, conductive heat transfer by the insulation material is prevented, and insulation performance can be stably maintained.

[0036] In addition, by applying insulation to the outer surface of the inner tank, liquefied gas can be stored with minimized heat loss and the evaporation rate (BOR) of the liquefied gas can be reduced.

[0037] In addition, by reducing the evaporation rate, the pressure rise caused by the evaporation of liquefied gas can be controlled, and cargo loss can also be minimized.

[0038] The effects of the present invention are not limited to the effects described above. Unmentioned effects will be clearly understood by those skilled in the art from this specification and the accompanying drawings.

[0039] FIG. 1 is a simplified cross-sectional view of a conventional liquefied gas storage tank.

[0040] FIG. 2 is a simplified cross-sectional view of a liquefied gas storage tank according to one embodiment of the present invention.

[0041] FIG. 3 is an enlarged view of a part of a liquefied gas storage tank according to one embodiment of the present invention, and is a drawing for explaining the principle of heat transfer blocking.

[0042] In order to fully understand the operational advantages of the present invention and the objectives achieved by the embodiments of the present invention, reference must be made to the accompanying drawings illustrating preferred embodiments of the present invention and the contents described therein.

[0043] The structure and operation of preferred embodiments of the present invention are described in detail below with reference to the attached drawings. It should be noted that in assigning reference numerals to the components of each drawing, identical components are denoted by the same numeral whenever possible, even if they are shown in different drawings. Furthermore, the following embodiments may be modified in various different forms, and the scope of the present invention is not limited to the following embodiments.

[0044]

[0045] In the embodiments of the present invention described below, the liquefied gas may be a liquefied gas capable of transporting gas by liquefying it at a low temperature, and may be, for example, a hydrocarbon-based liquefied gas such as LNG (Liquefied Natural Gas), LEG (Liquefied Ethane Gas), LPG (Liquefied Petroleum Gas), liquefied ethylene gas, liquefied propylene gas, liquefied methanol, liquefied ethanol, bio-oil, etc. Alternatively, it may be a non-hydrocarbon-based liquefied gas such as liquefied carbon dioxide, liquefied hydrogen, liquefied ammonia, etc.

[0046] In the embodiments of the present invention described below, the liquefied gas will be described based on the assumption that it is liquefied hydrogen.

[0047] In addition, while the embodiments of the present invention described below are explained as examples of applications to ships, they may also be applied on land.

[0048] Here, the term "ship" includes vessels with self-propulsion capabilities such as liquid hydrogen carriers (LH2 Carriers), LNG carriers, and LNG Regasification Vessels (LNG RVs), as well as offshore structures that are floating on the sea but do not have propulsion capabilities, such as LNG Floating Production Storage Offloading (FPSOs) and LNG Floating Storage Regasification Units (FSRUs).

[0049]

[0050] Hereinafter, a liquefied gas storage tank and a method for manufacturing the same according to embodiments of the present invention will be described with reference to FIGS. 2 and 3.

[0051] A liquefied gas storage tank (100) according to one embodiment of the present invention may include an inner tank (110) for receiving liquefied gas, an outer tank (120) arranged to surround the inner tank (110) at a certain distance from the outer side of the inner tank (110), a vacuum insulation space (130) formed between the inner tank (110) and the outer tank (120) and maintained in a vacuum state, and an adhesive insulation material (140) provided by being adhered to the outer surface of the inner tank (110) to block heat radiation transmitted to the inner tank (110).

[0052] The liquefied gas storage tank (100) according to the present embodiment is a double-insulated tank and may be a Type C independent tank classified by the International Maritime Organization (IMO).

[0053] In addition, the cross-section of the inner tank (110) according to the present embodiment is described as being circular or elliptical. A storage tank with a circular or elliptical cross-section has the advantage of generating less heat transfer and less evaporated gas compared to a storage tank with a different cross-section, and does not cause stress concentration.

[0054] An adhesive insulating material (140) is attached to the outer surface of the inner tank (110) of this embodiment, that is, the surface opposite to the one in contact with the liquefied gas, and radiant heat (Q) is transferred to the outer surface of the inner tank (110) by the adhesive insulating material (140). R ) can be blocked.

[0055] The adhesive insulation material (140) may be a cryogenic composite material in which a thermal radiation blocking material capable of blocking thermal radiation energy and a cryogenic material capable of withstanding an ultra-cold resistance cryogenic environment that can come into contact with the surface of the inner tank (110) are mixed.

[0056] In the embodiments, the thermal radiation blocking material is intended primarily to block thermal radiation and may be a material used to block thermal radiation by a reflection mechanism or a scattering mechanism.

[0057] The thermal radiation blocking material may be one or more selected from the group including glass bubbles, hollow glass microspheres, aluminum, or equivalent metallic materials.

[0058] In addition, the thermal radiation blocking material may include a metal material having a thermal radiation reflectance of 80% or more or an emissivity of 0.3 or less, and may include, for example, a metal powder selected from the group comprising aluminum, copper, nickel, chromium and alloys thereof or metal oxides.

[0059] In addition, the thermal radiation blocking material may include non-metals selected from the group including glass bubbles.

[0060] The cryogenic material may be one or more materials selected from the group including epoxy, polyimide, polyurethane, and silicone, and may further include other low-temperature additives.

[0061] In addition, the cryogenic material is a material that has adhesive properties in a cryogenic state, and by mixing the cryogenic material, even if cryogenic liquefied gas is stored in the inner tank (110), the adhesive insulation material (140) can be maintained in a state where it is adhered to the outer surface of the inner tank (110), and the adhesive insulation material (140) can maintain an appropriate thickness when it hardens.

[0062] In the embodiments, the cryogenic state may be -100℃ or lower.

[0063] For example, the adhesive insulation material (140) may be a mixture of glass bubbles and aluminum powder as a heat radiation blocking material and epoxy resin as a cryogenic material. In this embodiment, the description will be based on the assumption that the adhesive insulation material (140) is a mixture of glass bubbles, aluminum powder, and epoxy resin.

[0064] The adhesive insulation material (140) can be applied to the outer surface of the inner tank (110) by means of a spray gun or roller, etc., in the form of a semi-solid or semi-solid emulsion, for example, in the form of a cream or gel, by mixing glass bubbles, aluminum powder, and epoxy resin.

[0065] Additionally, the adhesive insulation material (140) applied to the outer surface of the inner tank (110) can be provided in a form that is adhered to the outer surface of the inner tank (110) after being hardened for a certain period of time.

[0066] Additionally, the adhesive insulation material (140) may be applied in the form of a cream or gel so that it can be maintained at a thickness greater than a preset thickness in a hardened state on the outer surface of the inner tank (110), and when liquefied gas is stored and transported in the inner tank (110), the adhesive insulation material (140) may be in a hardened state and adhered to the outer surface of the inner tank (110) at a thickness greater than a preset thickness.

[0067] Since an adhesive insulation material (140) is attached to the outer surface of the inner tank (110), heat transfer by radiation between the outer tank (120) and the inner tank (110) can be blocked.

[0068] In this embodiment, the adhesive insulation material (140) is a cryogenic composite material in which a thermal radiation blocking material and a cryogenic material are mixed, and the mixing ratio of the thermal radiation blocking material and the cryogenic material may vary depending on the material of the inner tank (110). In particular, the mixing ratio of the thermal radiation blocking material and the cryogenic material of the adhesive insulation material (140) is a ratio in which the adhesive insulation material (140) has thermal behavior similar to that of the material constituting the inner tank (110), and can be composed to correspond to the material characteristics of the inner tank (110).

[0069] The material of the inner tank (110) to which the adhesive insulation material (140) is applied may be a cryogenic steel such as stainless steel, nickel alloy steel, aluminum, and high manganese steel.

[0070] In the process of storing and transporting liquefied gas, the inner tank (110) undergoes thermal shrinkage due to a cryogenic environment, and due to the difference in thermal expansion coefficients between the material of the inner tank (110) and the material constituting the adhesive insulation (140), thermal stress damage may occur in the insulation, or a peeling phenomenon may occur in which the adhesive insulation (140) detaches from the surface of the inner tank (110).

[0071] The mixing ratio of the adhesive insulation material (140) can be adjusted so that the adhesive insulation material (140) can appropriately respond to the thermal behavior (thermal contraction, thermal expansion, etc.) exhibited by the inner tank (110) in a cryogenic environment of liquefied gas. This responsiveness can be achieved by configuring at least one of the thermal expansion coefficient, elastic modulus, or mechanical properties of the adhesive insulation material (140) to be in harmony with the corresponding properties of the inner tank (110).

[0072] According to embodiments of the present invention, the mixing ratio of the thermal radiation blocking material and the cryogenic material constituting the adhesive insulation material (140) is adjusted so as to have thermal behavior similar to that of the material constituting the inner tank (110), thereby manufacturing it in a semi-solid state, and by applying it to the surface of the inner tank (110) in a semi-solid state, the thermal insulation performance can be stably maintained by effectively responding to the thermal shrinkage and thermal expansion behavior of the inner tank (110).

[0073] For example, if the material of the inner tank (110) is stainless steel, the coefficient of thermal expansion of the inner tank (110) is approximately 16x10 -6 / ℃, and the mixing ratio of the heat radiation blocking material and the cryogenic material constituting the adhesive insulation material (140) may be 7:3 to 8:2 or 7.3:2.7 based on the volume ratio.

[0074] According to the embodiments, by optimizing the mixing ratio of the thermal radiation blocking material and the cryogenic adhesive resin constituting the adhesive insulation material (140) in consideration of the material and thermal characteristics of the inner tank (110), the stability of the interface between the inner tank (110) and the adhesive insulation material (140) in a cryogenic environment is secured, and the adhesive insulation material (140) is maintained in a state of close contact with the surface of the inner tank (110) over a long period of time, thereby continuously exhibiting excellent thermal insulation performance.

[0075] In addition, in the embodiments, the adhesive insulation material (140) is manufactured in a liquid, paste, semi-solid state or other state with a fluidity suitable for application, and after being applied to the outer surface of the inner tank (110), it is cured to form an integrated coating layer. This application-curing method has the advantage of being applicable to inner tanks of complex shapes with a uniform thickness and minimizing defects at the adhesive interface.

[0076] Meanwhile, the inner tank (110) and the outer tank (120) of the present embodiment are separated from each other by a vacuum insulation space (130) and, since the vacuum insulation space (130) is not filled with a medium that causes heat conduction, heat transfer by conduction between the outer tank (120) and the inner tank (110) can be blocked.

[0077] Additionally, the vacuum insulation space (130) of this embodiment may be in a vacuum state where the internal pressure is negative pressure (less than 0 barg). Since the vacuum insulation space (130) is maintained in a vacuum state, there are no molecules capable of causing thermal convection, so the convective heat (Q) between the outer tank (120) and the inner tank (110) is C ) Transmission may be blocked.

[0078] Meanwhile, the outer casing (120) of the present embodiment may include one or more domes (not given a reference numeral) as protrusions that are provided at the upper end and protrude outward. In this specification, the term "dome" may refer not only to a "dome" used in the conventional sense, but also to any part having a complex shape, such as a bent shape or a curved shape.

[0079] One or more domes may include a dome positioned at the uppermost part of the outer casing (120), i.e., the center, based on the state in which the liquefied gas storage tank (100) is supported on the floor, and one or more domes positioned on the left and right at regular intervals based on the dome positioned at the center. Among the one or more domes, the cross-sectional area of ​​the dome positioned at the center may be formed to be larger than the cross-sectional area of ​​the other one or more domes.

[0080] In addition, the upper part of the outer casing (120) according to the present embodiment may be provided with a gas discharge part (not shown) that communicates with the vacuum insulation space (130) and discharges gas from the vacuum insulation space (130).

[0081] Gas exhaust sections may be provided at least once on the upper surface of one or more domes and on the outer surface of the outer casing (120), respectively. Several gas exhaust sections may be arranged at regular intervals centered around the dome positioned in the middle among the one or more domes.

[0082] One or more domes and outer shells (120) can be formed so that the airtightness of the vacuum insulation space (130) can be maintained even if the gas discharge section penetrates and connects to the vacuum insulation space (130) and the outside.

[0083] The gas discharge section may be a valve or nozzle that can be remotely opened and closed by a control section not shown or by preset automatic logic. By opening the gas discharge section, the vacuum insulation space (130) can be vacuumed and the vacuum state of the vacuum insulation space (130) can be maintained.

[0084] In this embodiment, the vacuum insulation space (130) may include not only the space between the inner tank (110) and the outer tank (120), but also the dome interior space, which is an additional space formed by forming a dome.

[0085] In addition, the vacuum insulation space (130) of the present embodiment may be provided with a vacuum discharge pipe (not shown) connected to a vacuum pump (not shown) provided outside the liquefied gas storage tank (100) and for discharging gas inside the vacuum insulation space (130) to the outside through the lower part of the vacuum insulation space (130).

[0086] One side of the vacuum discharge pipe is connected to a vacuum insulation space (130), and the other side may be connected to a vacuum pump, which is a pressure reduction means for forming a vacuum in the vacuum insulation space (130).

[0087] The vacuum pump of the present embodiment can be used to reduce the pressure of the vacuum insulation space (130) or lower the vacuum level to create a vacuum by sucking gas into the vacuum insulation space (130) through the vacuum discharge pipe and discharging it downward from the vacuum insulation space (130).

[0088]

[0089] Next, a method for manufacturing a liquefied gas storage tank according to one embodiment of the present invention will be described.

[0090] A method for manufacturing a liquefied gas storage tank according to one embodiment of the present invention may include an adhesive insulation forming step in which an adhesive insulation material (140) is provided on the outer surface of an inner tank (110), a vacuuming step in which the vacuum level of a vacuum insulation space (130) is lowered, and a loading step in which liquefied gas is stored in the inner tank (110).

[0091] The adhesive insulation forming step may include an insulation manufacturing step of manufacturing the adhesive insulation (140) in a cream or gel type, an insulation application step of applying the cream or gel type adhesive insulation (140) to the outer surface of the inner tank (110), and an insulation bonding step of hardening the cream or gel type adhesive insulation (140) applied to the outer surface of the inner tank (110).

[0092] In the insulation material manufacturing step, glass bubbles, aluminum powder, and epoxy resin can be mixed to produce an adhesive insulation material (140) in the form of a cream or gel.

[0093] Additionally, in the insulation application step, a cream or gel-type adhesive insulation material (140) can be applied to the outer surface of the inner tank (110) using a spray gun or a roller.

[0094] In the insulation bonding step, the adhesive insulation material (140) applied to the outer surface of the inner tank (110) in the form of a cream or gel can be cured for a certain period of time until it hardens and adheres to the surface of the inner tank (110).

[0095] The vacuuming step of this embodiment can be performed when the vacuum insulation space (130) is empty. Additionally, the vacuuming step can be performed when the adhesive insulation material (140) is applied and bonded to the outer surface of the inner tank (110).

[0096] The vacuuming step can depressurize the vacuum insulation space (130) by operating a vacuum pump until the pressure inside the vacuum insulation space (130) becomes negative pressure (less than 0 barg).

[0097] When the vacuum pump is operated, gas inside the vacuum insulation space (130) is sucked in through the inlet of the vacuum discharge pipe and discharged to the outside, thereby reducing the pressure. When the vacuum insulation space (130) is reduced in pressure and vacuumed, it becomes possible to load liquefied gas into the inner tank (110).

[0098] For example, the vacuuming step can be carried out until the pressure inside the vacuum insulation space (130) becomes -1 barg.

[0099] In order to form a vacuum insulation space (130) in a vacuum or a state where there is a pressure difference with the outside, the vacuum insulation space (130) must be in a sealed state.

[0100] In addition, the vacuuming step can be carried out not only by operating a vacuum pump, but also by opening a gas discharge port to reduce the pressure of the vacuum insulation space (130).

[0101] When the vacuum insulation space (130) is vacuumed by the vacuuming step, the shipping step can be performed, and the vacuuming step and the shipping step may be performed in reverse order.

[0102]

[0103] Conventionally, by filling the vacuum insulation space (130) with powdered insulation material, the vacuuming process of the vacuum insulation space (130) was not only complex and difficult, but there was also a problem where heat conduction occurred due to the powdered insulation material, resulting in reduced insulation performance. In addition, there was also a problem where heat radiation occurred through the empty space created by the deposition characteristics of the powdered insulation material and the shrinkage of the inner tank (110), which lowered the insulation performance.

[0104] However, according to embodiments of the present invention, by maintaining the vacuum insulation space (130) in a vacuum state to block heat convection, and by applying a cream or gel-type adhesive insulation material (140) to the outer surface of the inner tank (110) and then hardening and bonding it, both heat conduction and heat radiation through the vacuum insulation space (130) can be blocked, thereby maximizing the insulation performance of the liquefied gas storage tank (100).

[0105] Generally, for medium to large tanks with a diameter of approximately 5m or more, applying conventional thin-film insulation presents significant difficulties in installation and management due to the large size, and for this reason, it is practically difficult to apply thin-film insulation to large tanks.

[0106] However, according to an embodiment of the present invention, by manufacturing the insulating material in a semi-solid state of a cream or gel type and applying it to the inner tank (110), the limitations of the thin film insulating material mentioned above can be overcome, and the insulating material can be easily installed even if the inner tank (110) is enlarged.

[0107] In addition, by manufacturing the adhesive insulation material (140) by adjusting the mixing ratio of the thermal radiation blocking material and the cryogenic material so that the adhesive insulation material (140) has thermal behavior similar to that of the material constituting the inner tank (110), the thermal shrinkage and expansion behavior of the inner tank (110) can be effectively responded to, thereby stably maintaining the insulation performance.

[0108]

[0109] As described above, embodiments according to the present invention have been examined. It is obvious to those skilled in the art that, in addition to the embodiments described above, the present invention may be embodied in other specific forms without departing from its spirit or scope. Therefore, the embodiments described above should be regarded as illustrative rather than restrictive, and accordingly, the present invention is not limited to the description above but may be modified within the scope of the appended claims and their equivalents.

[0110]

[0111] <Explanation of Symbols> 100: Liquefied gas storage tank, 110: Inner tank, 120: Outer tank, 130: Vacuum-insulated space, 140: Adhesive insulation

Claims

1. An inner tank for accommodating liquefied gas; An outer tank spaced apart from the outer side of the inner tank and arranged to surround the perimeter of the inner tank; A vacuum insulation space formed between the inner and outer tanks above, which blocks convective heat transfer in a vacuum state; and A liquefied gas storage tank comprising: an adhesive insulating material that is applied to the outer surface of the inner tank and adhered thereto to block thermal radiation energy transmitted to the inner tank.

2. In Claim 1, The above adhesive insulation is a cryogenic composite material comprising a thermal radiation blocking material capable of blocking thermal radiation energy and a cryogenic material capable of withstanding a cryogenic environment and having adhesive properties, for a liquefied gas storage tank.

3. In Claim 1, The above adhesive insulation material comprises one or more selected from a group of materials for blocking thermal radiation including glass bubbles, hollow glass microspheres, and aluminum, and further comprises one or more selected from a group including epoxy, polyurethane, polyimide, and silicone, for a liquefied gas storage tank.

4. In Claim 1, A liquefied gas storage tank, wherein the adhesive insulation material is in a semi-solid state when applied to the outer surface of the inner tank, and maintains a state in which the semi-solid hardens and is adhered to the outer surface of the inner tank at a thickness greater than or equal to a preset thickness when storing and transporting liquefied gas in the inner tank.

5. An adhesive insulation forming step in which an adhesive insulation is provided on the outer surface of an inner tank containing liquefied gas, and A vacuuming step for lowering the vacuum level of a vacuum insulation space formed between the inner and outer tanks to separate the inner and outer tanks, and A method for manufacturing a liquefied gas storage tank, comprising a loading step of storing liquefied gas in the above-mentioned inner tank.

6. In Claim 5, The above adhesive insulation forming step is, A step for manufacturing an insulation material that produces a composite material in a semi-solid state, and A thermal insulation application step of applying the above-mentioned semi-solid composite material to the outer surface of the above-mentioned inner tank, and A method for manufacturing a liquefied gas storage tank, comprising a thermal insulation bonding step for curing a semi-solid composite material applied to the outer surface of the inner tank.

7. In Claim 6, The above insulation application step is, A method for manufacturing a liquefied gas storage tank by applying a semi-solid composite material to a certain thickness using a spray gun or a roller.

8. In Claim 5, A method for manufacturing a liquefied gas storage tank, wherein the adhesive insulation material is a composite material comprising one or more selected from a group of materials for blocking thermal radiation including glass bubbles, hollow glass microspheres, and aluminum, and one or more selected from a group including epoxy, polyimide, polyurethane, and silicone.

9. In Claim 5, A method for manufacturing a liquefied gas storage tank, wherein in the above vacuuming step, a vacuum pump is operated or a gas discharge port is opened to depressurize the vacuum insulation space until the internal pressure of the vacuum insulation space becomes negative pressure, and the vacuum insulation space is empty and the application and adhesion of an adhesive insulation material to the outer surface of the inner tank is completed.

10. Inner tank for accommodating liquefied gas; An outer tank spaced apart from the outer side of the inner tank and arranged to surround the perimeter of the inner tank; A vacuum insulation space formed between the inner and outer tanks above, which blocks convective heat transfer in a vacuum state; and A liquefied gas storage tank with a double insulation structure comprising: an adhesive insulation material provided on the outer surface of the inner tank and configured to block thermal radiation energy transmitted to the inner tank; In the above vacuum-insulated space, there are no molecules capable of causing heat conduction or heat convection, and The above adhesive insulation material is a mixture comprising a thermal radiation blocking material and a cryogenic material having adhesive properties in a cryogenic state, mixed at a ratio that prevents delamination due to the difference in thermal expansion coefficients with the inner tank, and after being applied to the outer surface of the inner tank in a semi-solid state, maintained in an adhesive state with a thickness greater than a preset thickness. A liquefied gas storage tank, wherein the above-mentioned thermal radiation blocking material comprises one or more of glass bubbles or aluminum powder, and the above-mentioned cryogenic material comprises one or more selected from the group comprising epoxy, polyimide, and silicone.

11. A method for manufacturing a liquefied gas storage tank having a double insulation structure, comprising: an inner tank for receiving liquefied gas; an outer tank spaced apart from the outer side of the inner tank and arranged to surround the perimeter of the inner tank; a vacuum insulation space formed between the inner tank and the outer tank; and an adhesive insulation material provided on the outer surface of the inner tank to block thermal radiation energy transmitted to the inner tank. A step for manufacturing an insulating material, wherein a thermal radiation blocking material and a cryogenic material having adhesive properties in a cryogenic state are mixed in a mixing ratio that prevents delamination due to the difference in thermal expansion coefficients with the inner container to produce a semi-solid mixture; A step of forming an adhesive insulation material, wherein the adhesive insulation material is provided by applying the above-mentioned semi-solid mixture to the outer surface of the above-mentioned inner tank so that it is maintained in an adhesive state greater than or equal to a preset thickness, and A vacuuming step for creating a vacuum in the vacuum insulation space between the inner and outer tanks, and It includes a loading step of storing liquefied gas in the above-mentioned inner tank, and In the above vacuum-insulated space, there are no molecules capable of causing heat conduction or heat convection, and A method for manufacturing a liquefied gas storage tank, wherein the above-mentioned thermal radiation blocking material comprises one or more of glass bubbles or aluminum powder, and the above-mentioned cryogenic material comprises one or more selected from the group comprising epoxy, polyimide, and silicone.

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