Cooling system of liquefied gas storage tank and vessel including the same

Abstract

The present invention discloses a liquefied gas storage tank cooling system comprising: a standalone liquefied gas storage tank (110) that stores cryogenic liquefied gas, supported by a support (30) formed in a hold space (20) of a hull (10) and having a cargo dome (40) formed on top; an insulation section (120) that covers and insulates the tank shell (111) of the liquefied gas storage tank (110); a first pipe (130) disposed in the hold space (20) through which a heat transfer medium circulates; a second pipe (140) disposed inside the insulation section (120) through which a heat transfer medium circulates; and a cooling section (150) that cools the heat transfer medium to a temperature below a certain temperature by exchanging heat with the BOG exhausted through the cargo dome (40), thereby cooling the hold space (20) through the pipes (130, 140).

Description

Technology Field

[0001] The present invention relates to a liquefied gas storage tank cooling system and a ship including said system. More specifically, it relates to a liquefied gas storage tank cooling system and a ship including said system that can adjust the temperature factor used in calculating the design Boil-Off Rate (BOR) and can lower the design BOR without increasing the thickness of the insulation layer. Even more specifically, it relates to a liquefied gas storage tank cooling system and a ship including said system that cools the hold space through piping, cools the hold space by filling the hold space with cooling gas, and cools the hold space by supplying the gas filled in the annular space. Background Technology

[0002] Typically, natural gas is a fossil fuel containing methane, ethane, propane, etc., and is being utilized as a low-pollution energy source in various technological fields recently. It is transported to distant consumption sites while stored in storage tanks in the form of liquefied natural gas (LNG) or used as a propulsion fuel.

[0003] Meanwhile, storage tanks for storing liquefied natural gas can be classified into independent type and membrane type depending on whether the load of the cargo acts directly on the insulation material. The independent type is a method in which the storage tank is not formed integrally with the hull but is supported by the hull's support device as an independent storage tank, and the IMO classifies them into IMO Type A, Type B, and Type C depending on the number of barriers installed to prevent leakage of liquefied gas and the operating pressure.

[0004] Recently, cylindrical IMO Type B storage tanks are being manufactured that utilize a panel-type insulation system, similar to that of existing IMO Type B storage tanks, to secure an annular space for collecting liquefied gas leaking from the tank shell.

[0005] In particular, regarding liquefied natural gas (LNG) cargo tanks, there is a need for measures to suppress and treat boil-off gas (BOG). Conventionally, methods such as reinforcing insulation or pressurizing the cargo tanks have been used to suppress BOG; however, increasing the thickness of the insulation inevitably raises manufacturing costs due to the increased thickness of the tanks, and further increases in insulation thickness are limited considering the stability of the thermal insulation system and the size of the vessel. Prior art literature

[0006] Korean Published Patent Application No. 10-2022-0138540 (Liquefied gas storage tank and vessel equipped therewith, Oct. 13, 2022) Korean Registered Patent Application No. 10-1556262 (Liquefied gas cargo tank, Announced Oct. 01, 2015) The problem to be solved

[0007] The technical problem that the concept of the present invention aims to solve is to provide a liquefied gas storage tank cooling system and a vessel including said system, wherein the holding space is cooled through piping, the holding space is cooled by filling the holding space with cooling gas, and the holding space is cooled by supplying a gas filled in an annular space. means of solving the problem

[0008] To achieve the aforementioned objective, a first embodiment of the present invention provides a liquefied gas storage tank cooling system comprising: an independent liquefied gas storage tank that is supported by a support formed in the hold space of a hull, has a cargo dome formed on its upper surface, and stores cryogenic liquefied gas; an insulation section that covers and insulates the tank shell of the liquefied gas storage tank; a first pipe disposed in the hold space through which a first heat transfer medium circulates; a second pipe disposed inside the insulation section through which a second heat transfer medium circulates; and a cooling section that cools the first heat transfer medium and the second heat transfer medium to a temperature below a certain temperature by exchanging heat with the BOG exhausted through the cargo dome.

[0009] Here, the cooling unit can control the temperature of the first heat transfer medium circulating in the first pipe and the temperature of the second heat transfer medium circulating in the second pipe differently.

[0010] At this time, the first heat transfer medium and the second heat transfer medium may be a cold fluid.

[0011] In addition, a control unit for controlling the temperature or pressure of the first heat transfer medium circulating in the first pipe may be placed in the hold space.

[0012] In addition, a control unit for controlling the temperature or pressure of the first heat transfer medium circulating in the first pipe may be disposed in the first pipe.

[0013] In addition, an annular space may be formed between the tank shell and the insulation part.

[0014] In addition, the temperature of the hold space can be maintained in the range of 5°C to 20°C by the cooling unit.

[0015] In addition, the support may include a lower support coupled to the hull, an upper support coupled to the tank shell, and a wood block interposed between the lower support and the upper support.

[0016] Here, a third pipe may be further formed through which the first heat transfer medium circulates to cool the surrounding area of ​​the wood block.

[0017] At this time, the third pipe can be connected to the first pipe and the second pipe, respectively.

[0018] In addition, the first pipe, the second pipe, and the third pipe may be made of a heat conductor material.

[0019] In addition, the above liquefied gas storage tank may be IMO Type B.

[0020] In addition, the BOG heated by the cooling unit can be supplied to a BOG consumption site.

[0021] In addition, the above cryogenic liquefied gas may include LNG or liquefied hydrogen.

[0022] Meanwhile, to achieve the aforementioned objective, a second embodiment of the present invention provides a liquefied gas storage tank cooling system comprising: an independent liquefied gas storage tank that is supported by a support formed in the hold space of the hull and has a cargo dome formed on its upper side, and stores cryogenic liquefied gas; an insulation unit that covers and insulates the tank shell of the liquefied gas storage tank; a cooling gas supply unit that injects, circulates, and discharges cooling gas into the hold space; and a cooling unit that cools the cooling gas to a temperature below a certain temperature by exchanging heat with the BOG exhausted through the cargo dome.

[0023] Here, the cooling gas may be N2 or dry air.

[0024] In addition, a control unit for controlling the temperature or pressure of the cooling gas circulating in the hold space may be disposed in the hold space.

[0025] In addition, a control unit for controlling the temperature or pressure of the cooling gas circulating in the hold space may be placed in the inlet pipe or outlet pipe of the cooling gas supply unit.

[0026] Here, the temperature of the hold space can be maintained in the range of 5°C to 20°C by the cooling unit.

[0027] In addition, an annular space may be formed between the tank shell and the insulation part.

[0028] At this time, a pressure regulating unit may be further included to regulate the pressure of the annular space by injecting N2 or dry air into the annular space.

[0029] And, the above N2 or dry air may be N2 or dry air cooled by the cooling unit.

[0030] In addition, a pressure regulating pipe communicating between the above-mentioned hold space and the above-mentioned annular space may be arranged.

[0031] In addition, the support may include a lower support coupled to the hull, an upper support coupled to the tank cell, and a wood block interposed between the lower support and the upper support.

[0032] In addition, the above liquefied gas storage tank may be IMO Type B.

[0033] In addition, the BOG heated by the cooling unit can be supplied to a BOG consumption site.

[0034] Meanwhile, to achieve the aforementioned objective, a third embodiment of the present invention provides a liquefied gas storage tank cooling system comprising: an independent liquefied gas storage tank that is supported by a support formed in the hold space of the hull and has a cargo dome formed on its upper side, and stores cryogenic liquefied gas; an insulation unit that covers and insulates the tank shell of the liquefied gas storage tank; a cooling gas supply unit that injects cooling gas into an annular space formed between the tank shell and the insulation unit to circulate and discharge the annular space and the hold space; and a cooling unit that cools the cooling gas to a temperature below a certain temperature by exchanging heat with the BOG exhausted through the cargo dome.

[0035] Here, the cooling gas supply unit may include a first inlet pipe connected from the cooling unit to the annular space, a first outlet pipe connected from the annular space to the hold space, a second inlet pipe connected from the hold space to the annular space, and a second outlet pipe connected from the annular space to the outside of the liquefied gas storage tank.

[0036] In addition, a closed-loop circulation channel is formed in close contact with the surface of the tank shell, and the cooling gas that has been heat-exchanged by the cooling unit can flow through the circulation channel.

[0037] In addition, the above cooling gas may be N2 or dry air.

[0038] In addition, a control unit for controlling the temperature or pressure of the cooling gas circulating in the hold space may be disposed in the hold space.

[0039] In addition, the temperature of the hold space can be maintained in the range of 5°C to 20°C by the cooling unit.

[0040] In addition, the support may include a lower support coupled to the hull, an upper support coupled to the tank cell, and a wood block interposed between the lower support and the upper support.

[0041] In addition, the above liquefied gas storage tank may be IMO Type B.

[0042] In addition, the BOG heated by the cooling unit can be supplied to a BOG consumption site.

[0043] Meanwhile, the fourth embodiment of the present invention provides a vessel comprising a liquefied gas storage tank cooling system according to the first to third embodiments described above.

[0044] In this case, the vessel may be a liquefied gas carrier or a liquefied gas-fueled propulsion vessel. Effects of the invention

[0045] According to the present invention, by circulating a heat transfer medium through piping in the hold space to cool it, the temperature factor used in calculating the design BOR can be adjusted, and the design BOR can be lowered without increasing the thickness of the insulation layer.

[0046] In addition, by directly filling the hold space with cooling gas to cool it, the temperature factor used in the design BOR calculation can be adjusted, and the design BOR can be lowered without increasing the thickness of the insulation layer.

[0047] Furthermore, by cooling and supplying the gas filled in the annular space to cool the hold space, the temperature factor used in the calculation of the design BOR can be adjusted, and the design BOR can be lowered without increasing the thickness of the insulation layer. Brief explanation of the drawing

[0048] Figure 1 illustrates a configuration diagram of a liquefied gas storage tank cooling system according to a first embodiment of the present invention. Figure 2 shows the support and annular space of the liquefied gas storage tank cooling system of Figure 1 separated. FIG. 3 illustrates a configuration diagram of a liquefied gas storage tank cooling system according to a second embodiment of the present invention. Figure 4 shows the support and annular space of the liquefied gas storage tank cooling system of Figure 3 separated. FIG. 5 illustrates a configuration diagram of a liquefied gas storage tank cooling system according to a third embodiment of the present invention. Figure 6 shows the support and annular space of the liquefied gas storage tank cooling system of Figure 5 separated. Figure 7 illustrates the circulation path of the liquefied gas storage tank cooling system of Figure 5. Figure 8 presents a table showing the expected effects according to embodiments of the present invention. Specific details for implementing the invention

[0049] Hereinafter, embodiments of the present invention having the aforementioned features will be described in more detail with reference to the attached drawings.

[0050] The liquefied gas storage tank cooling system according to the first embodiment of the present invention is supported by a support (30) formed in the hold space (20) of the hull (10), has a cargo dome (40) formed on the upper part, and includes an independent liquefied gas storage tank (110) for storing cryogenic liquefied gas, an insulation section (120) that covers and insulates the tank shell (111) of the liquefied gas storage tank (110), a first pipe (130) disposed in the hold space (20) through which a heat transfer medium circulates, a second pipe (140) disposed inside the insulation section (120) through which a heat transfer medium circulates, and a cooling section (150) that cools the heat transfer medium to a temperature below a certain temperature by exchanging heat with the BOG exhausted through the cargo dome (40), and cools the hold space (20) through the pipes (130, 140).

[0051] Hereinafter, with reference to FIGS. 1 and FIGS. 2, the liquefied gas storage tank cooling system of the above-described configuration will be specifically described as follows.

[0052] First, the liquefied gas storage tank (110) is a standalone IMO Type B cargo tank for storing cryogenic liquefied gas, and is supported by a support (30) formed by extending vertically or horizontally in the hold space (20) of the hull (10) to maintain structural strength, and a cargo dome (40) with various piping lines installed on the top is formed.

[0053] Here, the cryogenic liquefied gas may include, but is not limited to, LNG or liquefied hydrogen, and may be any type of liquefied gas stored in a cryogenic state.

[0054] Next, the insulation part (120) covers the tank shell (111) of the liquefied gas storage tank (110) to insulate the outside air and minimize temperature changes of the cryogenic liquefied gas.

[0055] Here, the insulation part (120) may be a spray foam such as polyurethane foam or glass wool, a panel system to which plywood or polyurethane foam is applied, or reinforced polyurethane foam.

[0056] Additionally, as illustrated in the enlarged view of FIG. 2, an annular space (160) of the tank structure, which is in a vacuum or close to a vacuum state, can be formed between the tank shell (111) and the insulation part (120) to minimize the inflow and outflow of heat.

[0057] In addition, cryogenic liquefied gas leaking from the tank shell (111) can be collected in the annular space (160), and the collected cryogenic liquefied gas can be discharged into a drip tray (drawing symbol not shown).

[0058] Next, the first pipe (130) is placed in the hold space (20) as illustrated in FIG. 1, so that a heat transfer medium is introduced, separated from the internal space of the hold space (20), circulated through the pipe, and discharged to the outside, thereby lowering the temperature of the hold space (20) to 30°C or lower.

[0059] Additionally, a control unit (not shown) for controlling the temperature or pressure of a heat transfer medium circulating in the first pipe (130) may be placed in the hold space (20) or in the first pipe (130) to measure the temperature or pressure of the heat transfer medium through a sensor and control the amount of heat transfer medium input so that the control unit controls the temperature or pressure of the heat transfer medium within a preset range.

[0060] Next, the second pipe (140) can be placed inside the insulation section (120) covering the liquefied gas storage tank (110), as illustrated in FIG. 1, to allow a heat transfer medium to circulate, thereby reinforcing the insulation performance of the insulation section (120).

[0061] Next, the cooling unit (150) can heat exchange the heat transfer medium with the BOG exhausted through the cargo dome (40) to cool it to a constant temperature and supply it to the first pipe (130) and the second pipe (140), respectively.

[0062] Here, the cooling unit (150) may, through a separate cargo handling system, adjust the temperature of the heat transfer medium circulating in the first pipe (130) and the temperature of the heat transfer medium circulating in the second pipe (140) differently, and supply them to the first pipe (130) and the second pipe (140), respectively.

[0063] In addition, the BOG heated by the cooling unit (150) can be supplied to a BOG consumption site such as a propulsion engine, a power generation engine, or a re-liquefaction facility.

[0064] Meanwhile, the aforementioned heat transfer medium may be a cold fluid, and is not particularly limited as long as it is a medium capable of heat transfer.

[0065] In this way, through the cooling structure of the hold space (20) by the cooling unit (150), the temperature of the hold space (20) can be maintained in the range of 5°C to 20°C without using low-temperature steel, and if necessary, it may also be adjustable to the range of -35°C to +45°C.

[0066] Additionally, as illustrated in the enlarged view of FIG. 2, the support (30) may be composed of a lower support (31) coupled to the hull (10), an upper support (32) coupled to the tank shell (111), and a hardwood wood block (33) interposed between the lower support (31) and the upper support (32), and a third pipe (170) through which a heat transfer medium circulates to cool the surrounding area of ​​the wood block (33) may be formed to compensate for the insufficient thermal insulation performance of the wood block (33) and minimize heat transfer by conduction through the support (30).

[0067] To this end, the third pipe (170) is connected to the first pipe (130) and the second pipe (140) respectively so as to communicate with each other, allowing the heat transfer medium to circulate around the area of ​​the wood block (33).

[0068] Additionally, the first pipe (130), the second pipe (140), and the third pipe (170) may be made of various materials such as stainless steel, copper alloy, nickel alloy, and aluminum alloy, which are thermal conductor materials with good thermal conductivity, and are not specifically limited thereto.

[0069] Accordingly, by means of the liquefied gas storage tank cooling system according to the first embodiment as described above, a heat transfer medium is circulated through piping in the hold space to cool it, thereby allowing the temperature factor used in the calculation of the design Boil-Off Rate (BOR) to be adjusted and the design BOR to be lowered without increasing the thickness of the insulation layer.

[0070] The second embodiment of the present invention is supported by a support (30) formed in the hold space (20) of the hull (10), and has a cargo dome (40) formed on the upper part, and includes an independent liquefied gas storage tank (210) for storing cryogenic liquefied gas, an insulation section (220) that covers and insulates the tank shell (211) of the liquefied gas storage tank (210), a cooling gas supply section (230) that injects, circulates, and discharges cooling gas into the hold space (20), and a cooling section (240) that cools the cooling gas to a temperature below a certain temperature by exchanging heat with the BOG exhausted through the cargo dome (40), and fills the hold space (20) with cooling gas to cool the hold space (20).

[0071] Hereinafter, with reference to FIGS. 3 and FIGS. 4, the liquefied gas storage tank cooling system of the above-described configuration will be specifically described as follows.

[0072] First, the liquefied gas storage tank (210) is a standalone IMO Type B cargo tank for storing cryogenic liquefied gas, and is supported by a support (30) formed by extending vertically or horizontally in the hold space (20) of the hull (10) to maintain structural strength, and a cargo dome (40) with various piping lines installed on the top is formed.

[0073] Here, the cryogenic liquefied gas may include LNG or liquefied hydrogen, but is not limited thereto, and may include all types of liquefied gas stored in a cryogenic state.

[0074] Next, the insulation part (220) covers the tank shell (211) of the liquefied gas storage tank (210) to insulate the outside air and minimize temperature changes of the cryogenic liquefied gas.

[0075] Here, the insulation part (220) may be a spray foam such as polyurethane foam or glass wool, a panel system to which plywood or polyurethane foam is applied, or reinforced polyurethane foam.

[0076] Additionally, as illustrated in the enlarged view of FIG. 4, an annular space (250) of the tank structure, which is in a vacuum or close to a vacuum state, can be formed between the tank shell (211) and the insulation part (220) to minimize the inflow and outflow of heat.

[0077] In addition, cryogenic liquefied gas leaking from the tank shell (211) can be collected in the annular space (250), and the collected cryogenic liquefied gas can be discharged into a drip tray (not shown in the drawing).

[0078] Meanwhile, as illustrated in enlarged view in FIG. 4, a pressure regulating unit (260) (see FIG. 3) that regulates the pressure of the annular space (250) by injecting N2 or dry air into the annular space (250) can be further included to regulate the pressure difference occurring between the hold space (20) and the annular space (250) to increase stability.

[0079] Here, referring to FIGS. 3 and 4, the N2 or dry air supplied through the pressure control unit (260) may be N2 or dry air cooled by the cooling unit (240), so that the annular space (250) may be additionally cooled.

[0080] Additionally, referring to FIG. 3, as previously mentioned, a pressure regulating pipe (270) communicating between the hold space (20) and the annular space (250) may be arranged so as to regulate the pressure difference and perform additional cooling through the cooling gas filled in the hold space (20) without having a pressure regulating unit (260).

[0081] Next, the cooling gas supply unit (230) injects, circulates, and discharges cooling gas into the hold space (20). An inlet pipe (231) and an outlet pipe (232) are formed at the top of the hold space (20), so that cooling gas is injected through the inlet pipe (231), circulates through the internal space of the hold space (20), and is exhausted through the outlet pipe (232), thereby cooling the temperature of the hold space (20) to 30°C or lower.

[0082] Here, the cooling gas filled into the hold space (20) may be cooled N2 or dry air.

[0083] Additionally, a control unit (not shown) for controlling the temperature or pressure of the cooling gas circulating in the hold space (20) may be placed in the hold space (20) to measure the temperature or pressure of the cooling gas through a sensor (not shown) and to control the amount of cooling gas input so that the control unit controls the temperature or pressure of the cooling gas within a preset range.

[0084] For example, the control unit and the sensor may be positioned adjacent to the inlet pipe (231) or outlet pipe (232) of the cooling gas supply unit (230).

[0085] Next, the cooling unit (240) can heat exchange the cooling gas with the BOG exhausted through the cargo dome (40) to cool it to a constant temperature and supply it to the inlet pipe (231).

[0086] In addition, the BOG heated by the cooling unit (240) can be supplied to a BOG consumption site such as a propulsion engine, a power generation engine, or a re-liquefaction facility.

[0087] In this way, through the cooling structure of the hold space (20) by the cooling unit (240), the temperature of the hold space (20) can be maintained in the range of 5°C to 20°C, and if necessary, it may also be adjustable to the range of -35°C to +45°C.

[0088] Additionally, as illustrated in the enlarged view of FIG. 4, the support (30) may be composed of a lower support (31) coupled to the hull (10), an upper support (32) coupled to the tank shell (211), and a hard wood block (33) interposed between the lower support (31) and the upper support (32), and the cooling gas of the hold space (20) may come into direct contact with the wood block (33) to compensate for the poor thermal insulation performance of the wood block (33) and minimize heat transfer by conduction through the support (30).

[0089] Accordingly, by means of the liquefied gas storage tank cooling system according to the second embodiment as described above, the holding space is cooled by directly filling the holding space with cooling gas, thereby allowing the temperature factor used in the calculation of the design BOR to be adjusted and the design BOR to be lowered without increasing the thickness of the insulation layer.

[0090] The liquefied gas storage tank cooling system according to the third embodiment of the present invention is supported by a support (30) formed in the hold space (20) of the hull (10), has a cargo dome (40) formed on the upper part, and includes an independent liquefied gas storage tank (310) that stores cryogenic liquefied gas, an insulation section (320) that covers and insulates the tank shell (311) of the liquefied gas storage tank (310), a cooling gas supply section (340) that injects cooling gas into an annular space (330) formed between the tank shell (311) and the insulation section (320) to circulate and discharge the annular space (330) and the hold space (20), and a cooling section (350) that cools the cooling gas to a temperature below a certain temperature by exchanging heat with the BOG exhausted through the cargo dome (40), and the cooling gas filled in the annular space (330) is cooled and supplied to cool the hold space (20).

[0091] Hereinafter, with reference to FIGS. 5 to 7, the liquefied gas storage tank cooling system of the above-described configuration will be specifically described as follows.

[0092] First, the liquefied gas storage tank (310) is a cargo tank corresponding to an independent IMO Type B that stores cryogenic liquefied gas, and is supported by a support (30) formed by extending vertically or horizontally in the hold space (20) of the hull (10) to maintain structural strength, and a cargo dome (40) with various piping lines installed on the top is formed.

[0093] Here, the cryogenic liquefied gas stored in the liquefied gas storage tank (310) may include LNG or liquefied hydrogen, but is not limited thereto, and includes all types of liquefied gas stored in a cryogenic state.

[0094] Next, the insulation part (320) covers the tank shell (311) of the liquefied gas storage tank (310) to insulate the outside air and minimize temperature changes of the cryogenic liquefied gas.

[0095] Here, the insulation part (320) may be a spray foam such as polyurethane foam or glass wool, a panel system to which plywood or polyurethane foam is applied, or reinforced polyurethane foam.

[0096] In addition, as illustrated in the enlarged view of FIG. 6, a vacuum or near-vacuum space (330) of the tank structure can be formed between the tank shell (311) and the insulation part (320) to minimize the inflow and outflow of heat.

[0097] In addition, cryogenic liquefied gas leaking from the tank shell (311) can be collected in the annular space (330), and the collected cryogenic liquefied gas can be discharged into a drip tray (drawing symbol not shown).

[0098] Next, the cooling gas supply unit (340) injects cooling gas into the annular space (330) formed between the tank shell (311) and the insulation unit (320) to circulate the annular space (330) and the hold space (20) to cool the temperature of the hold space (20) to 30°C or lower and discharge it to the outside of the liquefied gas storage tank (310).

[0099] Specifically, as illustrated in FIG. 5, the cooling gas supply unit (340) is composed of a first inlet pipe (341) connected from the cooling unit (350) to the annular space (330), a first outlet pipe (342) connected from the annular space (330) to the hold space (20), a second inlet pipe (343) connected from the hold space (20) to the annular space (330), and a second outlet pipe (344) connected from the annular space (330) to the outside of the liquefied gas storage tank (310). The cooling gas supplied through the first inlet pipe (341) cools the annular space (330), is discharged into the hold space (20) through the first outlet pipe (342) to cool the hold space (20), and the circulated cooling gas flows into the hold space (20) through the second inlet pipe (343) to the second outlet It can be discharged to the outside through the pipe (344).

[0100] Here, the cooling gas may be cooled N2 or dry air.

[0101] Additionally, as illustrated in FIG. 7, a closed-loop circulation channel (360) is formed in close contact with the surface of the tank shell (311) and configured to withstand the pressure of the liquefied gas storage tank (310), and the cooling gas that has been heat-exchanged by the cooling unit (350) is allowed to flow through the circulation channel (360) so that the cooling gas, which has been further cooled by utilizing the cold heat on the surface of the tank shell (311), can be discharged.

[0102] Next, the cooling unit (350) can heat exchange the cooling gas with the BOG exhausted through the cargo dome (40) to cool it to a constant temperature and supply it to the cooling gas supply unit (340).

[0103] In addition, the BOG heated by the cooling unit (350) can be supplied to a BOG consumption site such as a propulsion engine, a power generation engine, or a re-liquefaction facility.

[0104] Additionally, a control unit (not shown) for controlling the temperature or pressure of the cooling gas circulating in the hold space (20) may be placed in the hold space (20) to measure the temperature or pressure of the cooling gas through a sensor (not shown) and to control the amount of cooling gas input so that the control unit controls the temperature or pressure of the cooling gas within a preset range.

[0105] Through the cooling structure of the hold space (20) as described above, the temperature of the hold space (20) can be maintained in the range of 5°C to 20°C by the cooling unit (350), and if necessary, it may also be adjustable to the range of -35°C to +45°C.

[0106] Additionally, as illustrated in the enlarged view of FIG. 6, the support (30) may be composed of a lower support (31) coupled to the hull (10), an upper support (32) coupled to the tank shell (311), and a hard wood block (33) interposed between the lower support (31) and the upper support (32), and the cooling gas of the hold space (20) may come into direct contact with the wood block (33) to compensate for the poor thermal insulation performance of the wood block (33) and minimize heat transfer by conduction through the support (30).

[0107] Accordingly, by means of the liquefied gas storage tank cooling system according to the third embodiment as described above, the gas filled in the annular space is cooled and supplied to cool the hold space, thereby allowing the temperature factor used in the calculation of the design BOR to be adjusted and the design BOR to be lowered without increasing the thickness of the insulation layer.

[0108] Meanwhile, Figure 8 presents a table showing the expected effects of the embodiments of the present invention. By referring to this, it can be seen that when the temperature inside the hold space is reduced by 5 degrees, the design BOR improves by 3%, and there is an advantage that the design BOR can be improved without large-scale design changes to the steel grade and the hull / hull shape itself.

[0109] In addition, the area where the aforementioned cargo dome (40) is formed is a high-temperature area, and the temperature can be controlled through a coffer dam (not shown) in that space. For example, the heat transfer medium or cooling gas that has been heat-exchanged by the cooling unit may be configured to pass through the coffer dam first to cool the coffer dam before being supplied to the hold space or annular space.

[0110] Meanwhile, the fourth embodiment of the present invention provides a vessel comprising a liquefied gas storage tank cooling system according to the first to third embodiments described above.

[0111] In this case, the vessel may be a liquefied gas carrier or a liquefied gas-fueled vessel. For example, it may be an LNG carrier or a liquefied hydrogen carrier, or an LNG-fueled vessel or a hydrogen-fueled vessel.

[0112] The embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention; therefore, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application. Explanation of the symbols

[0113] 10 : Hull 20 : Hold space 30 : Support 31 : Bottom support 32 : Top support 33 : Wood block 40 : Cargo Dome 110 : Liquefied Gas Storage Tank 111 : Tank shell 120 : Insulation section 130 : 1st pipe 140 : 2nd pipe 150 : Cooling section 160 : Illusion space 170 : 3rd pipe 210: Liquefied gas storage tank 211: Tank shell 220 : Insulation section 230 : Cooling gas supply section 231: Inlet Piping 232: Outlet Piping 240 : Cooling section 250 : Illusion space 260 : Pressure regulator 270 : Pressure regulating piping 310: Liquefied gas storage tank 311: Tank shell 320 : Insulation section 330 : Annular space 340: Cooling gas supply unit 341: First inlet pipe 342: 1st outlet pipe 343: 2nd inlet pipe 344: 2nd outlet pipe 350: Cooling section 360 : Circulation path

Claims

Claim 1 A standalone liquefied gas storage tank that stores cryogenic liquefied gas, supported by a support formed in the hold space of the hull and having a cargo dome formed on its upper surface; an insulation section that covers and insulates the tank shell of the liquefied gas storage tank; a first pipe disposed adjacent to the inner wall of the hold space but separated from the internal space of the hold space, through which a first heat transfer medium circulates; and a second pipe disposed inside the insulation section through which a second heat transfer medium circulates. A cooling unit comprising: a first heat transfer medium and a second heat transfer medium that exchange heat with BOG exhausted through the cargo dome to cool to a temperature below a certain temperature; wherein the support comprises a lower support coupled to the hull, an upper support coupled to the tank shell, and a wood block interposed between the lower support and the upper support, and a third pipe through which the first heat transfer medium circulates to cool the surrounding area of ​​the wood block is further formed, and wherein the third pipe is connected to the first pipe and the second pipe, respectively. Claim 2 A liquefied gas storage tank cooling system according to claim 1, wherein the cooling unit controls the temperature of the first heat transfer medium circulating in the first pipe and the temperature of the second heat transfer medium circulating in the second pipe differently. Claim 3 A liquefied gas storage tank cooling system according to claim 2, wherein the first heat transfer medium and the second heat transfer medium are cold fluids. Claim 4 A liquefied gas storage tank cooling system according to claim 1, characterized in that a control unit for controlling the temperature or pressure of the first heat transfer medium circulating in the first pipe is disposed in the hold space. Claim 5 A liquefied gas storage tank cooling system according to claim 1, characterized in that a control unit for controlling the temperature or pressure of the first heat transfer medium circulating in the first pipe is disposed in the first pipe. Claim 6 A liquefied gas storage tank cooling system according to claim 1, characterized in that an annular space is formed between the tank shell and the insulation part. Claim 7 A liquefied gas storage tank cooling system according to claim 1, characterized in that the temperature of the hold space is maintained in the range of 5°C to 20°C by the cooling unit. Claim 8 delete Claim 9 delete Claim 10 delete Claim 11 A liquefied gas storage tank cooling system according to claim 1, wherein the first pipe, the second pipe, and the third pipe are made of a thermal conductor material. Claim 12 A liquefied gas storage tank cooling system according to claim 1, characterized in that the liquefied gas storage tank is an IMO Type B. Claim 13 A liquefied gas storage tank cooling system according to claim 1, characterized in that the BOG heated by the cooling unit is supplied to a BOG consumption site. Claim 14 A liquefied gas storage tank cooling system according to claim 1, characterized in that the cryogenic liquefied gas comprises LNG or liquefied hydrogen. Claim 15 A vessel comprising a liquefied gas storage tank cooling system according to any one of claims 1 to 7 and claims 11 to 14. Claim 16 delete Claim 17 delete Claim 18 delete Claim 19 delete Claim 20 delete Claim 21 delete Claim 22 delete Claim 23 delete Claim 24 delete Claim 25 delete Claim 26 delete Claim 27 delete Claim 28 delete Claim 29 A liquefied gas storage tank cooling system comprising: an independent liquefied gas storage tank supported by a support formed in the hold space of the hull, having a cargo dome formed on the upper part, and storing cryogenic liquefied gas; an insulation section covering and insulating the tank shell of the liquefied gas storage tank; a cooling gas supply section injecting cooling gas into an annular space formed between the tank shell and the insulation section to circulate and discharge the annular space and the hold space; and a cooling section cooling the cooling gas to a temperature below a certain temperature by exchanging heat with the BOG exhausted through the cargo dome; wherein a closed-loop circulation path is formed within the annular space and is in close contact with the surface of the tank shell, and the cooling gas that has exchanged heat by the cooling section flows through the circulation path. Claim 30 A liquefied gas storage tank cooling system according to claim 29, wherein the cooling gas supply unit comprises a first inlet pipe connected from the cooling unit to the annular space, a first outlet pipe connected from the annular space to the hold space, a second inlet pipe connected from the hold space to the annular space, and a second outlet pipe connected from the annular space to the outside of the liquefied gas storage tank. Claim 31 delete Claim 32 A liquefied gas storage tank cooling system according to claim 29, wherein the cooling gas is N2 or dry air. Claim 33 A liquefied gas storage tank cooling system according to claim 29, characterized in that a control unit for controlling the temperature or pressure of the cooling gas circulating in the hold space is disposed in the hold space. Claim 34 A liquefied gas storage tank cooling system according to claim 29, characterized in that the temperature of the hold space is maintained in the range of 5°C to 20°C by the cooling unit. Claim 35 A liquefied gas storage tank cooling system according to claim 29, wherein the support comprises a lower support coupled to the hull, an upper support coupled to the tank shell, and a wood block interposed between the lower support and the upper support. Claim 36 A liquefied gas storage tank cooling system according to claim 29, wherein the liquefied gas storage tank is IMO Type B. Claim 37 A liquefied gas storage tank cooling system according to claim 29, characterized in that the BOG heated by the cooling unit is supplied to a BOG consumption site. Claim 38 A vessel comprising a liquefied gas storage tank cooling system according to any one of Articles 29, 30, and 32 through 37.

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