Isolation system for liquefied gas storage tank and ship comprising same

Abstract

The present invention comprises: a main barrier in contact with a liquefied gas; an isolation layer disposed outside the main barrier; a leakage flow path formed between the main barrier and the isolation layer and having an outlet through which the liquefied fluid leaked from the main barrier flows; a leakage flow through passage inserted into the insulating layer, connected to the leakage flow path, and allowing leaked liquefied gas to pass therethrough; and a partial auxiliary barrier communicating with the leakage flow through-passage and configured in the form of a duct, where, in the event of a leakage of the main barrier, the leaked liquefied gas is completely vaporized when passing through the partial auxiliary barrier configured in the form of the duct.

Description

Technical Field

[0001] The present invention relates to an insulation system for a liquefied gas storage tank and a ship including the same, and more particularly to an insulation system for a liquefied gas storage tank that meets leakage standards by completely vaporizing leaked liquefied gas from the storage tank within a pipe-type partial auxiliary barrier, and a ship including the same. Background Art

[0002] Generally, natural gas is transported in a gaseous state through onshore or offshore gas pipelines, or stored in an LNG carrier in the form of liquefied natural gas (LNG) and transported to distant consumers.

[0003] Storage tanks for liquefied gases such as liquefied natural gas (LNG) and liquefied hydrogen (LH2), and transportation means or structures including these storage tanks require a series of fittings and equipment for storing and managing the liquefied gas in the storage tank. These fittings and equipment need to meet all conditions including temperature, pressure, etc., which are necessary for storing and managing the liquefied gas, and need to have a design that takes these conditions into account.

[0004] The technology of liquefied gas storage is generally classified into a thin-film storage tank and an independent storage tank according to the classification standards specified in the IGC Code or onshore storage tank technology. In particular, the independent storage tank can be divided into three main types according to the configuration method of the secondary barrier: type A, type B, and type C. In particular, for a type B independent storage tank, the secondary barrier is configured as a partial secondary barrier. This partial secondary barrier needs to have liquidtightness.

[0005] The type B independent storage tank is designed / manufactured in a ship in the form of a spherical storage tank, a prismatic storage tank, etc., in which a partial secondary barrier is installed in the form of a drip tray at the lower end of the storage tank, and the drip tray is connected to a passage through which leaked liquefied gas can be discharged.

[0006] This drip tray is firmly installed on the bottom surface of the storage tank to receive the fluid (LNG) flowing downward due to gravity. In addition, the drip tray has an internal space and is installed at one or more positions on the bottom surface of the storage tank to collect the downward flowing cryogenic fluid.

[0007] Although this drip tray is used to protect the hull temporarily for 15 days, the drip tray needs to have a very large size to accommodate the leaked cryogenic fluid in the liquid state during this period. Therefore, a practical alternative that does not require airtightness is needed.

[0008] In addition, when the bottom surface of the storage tank is relatively flat, due to the need to install multiple drip trays, the complexity in a small space increases. Summary of the Invention

[0009] Technical Problem

[0010] Embodiments of the present invention are intended to solve such problems in the prior art. One aspect of the present invention is to provide an isolation system for a liquefied gas storage tank, which meets the leakage standard by completely vaporizing the leaked liquefied gas from the storage tank within the pipe-type partial auxiliary barrier, rather than using a typical drip-tray-type partial auxiliary barrier to collect the leaked liquefied gas.

[0011] Another aspect of the present invention is to provide an isolation system for a liquefied gas storage tank, which does not require excessive space to install the partial auxiliary barrier and is not restricted by space constraints.

[0012] Technical Solution

[0013] According to one aspect of the present invention, there is provided an isolation system for a liquefied gas storage tank, including: a main barrier in contact with the liquefied gas; an isolation layer disposed outside the main barrier; a leakage flow path formed between the main barrier and the isolation layer and having an outlet through which the liquefied gas leaked from the main barrier flows; a leakage flow-through channel inserted into the isolation layer, connected to the leakage flow path, and allowing the leaked liquefied gas to pass through; and a partial auxiliary barrier communicating with the leakage flow-through channel and configured in the form of a pipe. In the case of leakage in the main barrier, the leaked liquefied gas is completely vaporized when passing through the partial auxiliary barrier configured in the form of a pipe.

[0014] The partial auxiliary barrier may be connected to the leakage flow-through channel at one end thereof and may form a gas opening at the other end to discharge the liquefied gas vaporized within the partial auxiliary barrier.

[0015] The partial auxiliary barrier can be configured in the form of a pipe having an internal space and can have a shape selected from a straight shape, a curved shape, a zigzag shape, a spring shape, and a radial shape to increase the length.

[0016] The partial auxiliary barrier may be connected to the leakage flow-through channel in a liquid-tight manner by one of welding, threaded connection, or bolt connection.

[0017] The leakage flow-through channel may include one or more leakage flow-through channels disposed at different positions of the liquefied gas storage tank and communicating with the partial auxiliary barrier.

[0018] The isolation system may further include a connecting pipe that serially connects one leakage flow-through channel to another adjacent leakage flow-through channel, and a part of the auxiliary barrier may be connected to the most downstream one of the leakage flow-through channels serially connected to each other by the connecting pipe.

[0019] The isolation system may further include a connecting pipe that connects a corresponding one of the leakage flow-through channels to a part of the auxiliary barrier.

[0020] The part of the auxiliary barrier may include a pipe formed of a metal that can serve as a barrier material suitable for liquefied gas.

[0021] According to another aspect of the present invention, there is provided a ship including an isolation system connected to a liquefied gas storage tank.

[0022] Advantageous Effects

[0023] Embodiments of the present invention provide an isolation system for a liquefied gas storage tank, which complies with leakage standards by completely vaporizing leaked liquefied gas from the storage tank within a pipe-type partial auxiliary barrier, thus eliminating the need to install a typical drip tray.

[0024] In addition, embodiments of the present invention provide an isolation system for a liquefied gas storage tank, particularly for a type B independent storage tank, which does not require excessive space to install a partial auxiliary barrier and is not restricted by space constraints. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a cross-sectional view of an installation area of a pipe-type partial auxiliary barrier in an isolation system for a liquefied gas storage tank according to an embodiment of the present invention.

[0026] Figure 2 (a), (b), (c), (d), (e), and (f) thereof are exemplary diagrams showing various shapes of a partial auxiliary barrier used in an isolation system for a liquefied gas storage tank according to an embodiment of the present invention.

[0027] Figure 3 is a schematic diagram showing a coupling structure of an isolation system for a liquefied gas storage tank according to an embodiment of the present invention.

[0028] Figure 4 is a schematic diagram showing a coupling structure of an isolation system for a liquefied gas storage tank according to another embodiment of the present invention. DETAILED DESCRIPTION

[0029] The above and other aspects, features, and advantages of the present invention will become apparent from the following detailed description of embodiments in conjunction with the accompanying drawings. It should be noted that throughout the specification and all the drawings, the same components will be denoted by the same reference numerals. In addition, descriptions of known functions and structures that may unnecessarily obscure the subject matter of the present invention will be omitted.

[0030] It should be understood that the drawings are provided for the convenience of understanding the embodiments disclosed in this specification and are not intended to limit the technical concepts disclosed herein. In addition, it should be understood that the present invention includes all modifications, equivalents, and alternatives within the spirit and scope of the invention.

[0031] In addition, it will be understood that although terms such as "first", "second", etc. may be used herein to describe various elements, components, regions, layers, and / or parts, these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or part from another element, component, region, layer, or part.

[0032] Herein, the term "liquefied gas" is intended to include all gaseous fuels that are normally stored in a liquid state, such as liquefied natural gas (LNG), liquefied hydrogen, liquefied nitrogen, liquefied petroleum gas (LPG), ethylene, and ammonia, and for the sake of convenience of description, may also refer to gaseous fuels that are not in a liquid state due to heating or pressurization. This definition also applies to boil-off gas. In addition, herein, the term "LNG" may be used broadly to include not only liquid LNG but also LNG in a supercritical state, while the term "boil-off gas" may refer to not only gaseous boil-off gas but also liquefied boil-off gas.

[0033] In addition, herein, the terms "primary" and "secondary" are used to distinguish the function of primarily sealing or isolating a storage tank storing LNG from the function of secondarily sealing or isolating the storage tank.

[0034] In addition, by convention, regardless of the direction of gravity, the terms "upper" or "top" applied to elements of a storage tank refer to the direction toward the inside of the storage tank. Similarly, regardless of the direction of gravity, the terms "lower" or "bottom" refer to the direction toward the outside of the storage tank.

[0035] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each drawing, the same reference numerals denote the same components.

[0036] It should be noted that a ship equipped with the following liquefied gas storage tank includes not only a merchant ship that transports goods from a starting point to a destination but also an offshore structure that floats at a specific point at sea and performs a specific task. In addition, it should be noted that herein, the term "liquefied gas storage tank" refers to any type of storage tank for storing liquefied gas.

[0037] The present invention can be applied to a type B independent liquefied gas storage tank including an auxiliary barrier formed as a partial auxiliary barrier and requiring liquid tightness.

[0038] Figure 1 It is a cross-sectional view of the installation area of a pipe-type partial auxiliary barrier in an isolation system for a liquefied gas storage tank according to an embodiment of the present invention. Figure 2 Examples (a), (b), (c), (d), (e), and (f) are exemplary diagrams showing various shapes of a partial auxiliary barrier used in an isolation system for a liquefied gas storage tank according to an embodiment of the present invention. Figure 3 It is a schematic diagram showing the coupling structure of an isolation system for a liquefied gas storage tank according to an embodiment of the present invention. Figure 4 It is a schematic diagram showing the coupling structure of an isolation system for a liquefied gas storage tank according to another embodiment of the present invention.

[0039] Referring to Figure 1 According to this embodiment, the isolation system for a liquefied gas storage tank includes: a main barrier (100) in contact with the liquefied gas; an isolation layer (200) provided outside the main barrier (100); a leakage flow path (300) formed between the main barrier (100) and the isolation layer (200) and allowing the liquefied gas leaking from the main barrier (100) to flow through; a leakage flow through channel (400) inserted into the isolation layer (200), connected to the leakage flow path (300), and allowing the leaking liquefied gas to pass through; and a partial auxiliary barrier (500) communicating with the leakage flow through channel (400) and configured in the form of a pipe. In the case where the main barrier (100) leaks, the leaking liquefied gas is completely vaporized when passing through the partial auxiliary barrier (500) configured in the form of a pipe.

[0040] Specifically, the main barrier (100) of the isolation system for a liquefied gas storage tank according to this embodiment can be configured to directly contact and confine the liquefied gas, and can be formed of a metal suitable for the characteristics of the liquefied gas, such as aluminum, nickel alloy steel, high manganese steel, stainless steel, and nickel.

[0041] The leakage flow path (300) of the isolation system for a liquefied gas storage tank according to this embodiment is formed between the main barrier (100) and the isolation layer (200) and serves as a channel for the liquefied gas leaking from the main barrier (100) to flow through. Specifically, the leakage flow path (300) provides a space for transporting the liquid liquefied gas leaking from the storage tank due to damage to the main barrier (100).

[0042] In addition, the leakage flow path (300) may have an outlet (310) formed in the direction of the isolation layer (200) so as to discharge the leaking liquefied gas through the leakage flow through channel (400) described below.

[0043] The leakage flow-through channel (400) of the insulation system for a liquefied gas storage tank according to the present embodiment can be configured in the form of a small-diameter pipe that is inserted into and passes through the insulation layer (200) to communicate with the outlet (310) of the leakage flow path (300) and allows the leaked liquefied gas to pass through it. Specifically, since the leakage flow-through channel (400) is a channel that penetrates the insulation layer (200) and allows the leaked liquefied gas to flow to the outside of the storage tank, the leakage flow-through channel (400) can be formed of a material suitable for the characteristics of the liquefied gas. When the liquefied gas is LNG, the leakage flow-through channel is preferably formed of aluminum steel, stainless steel or similar materials.

[0044] In addition, the leakage flow-through channel (400) of the insulation system for a liquefied gas storage tank according to the present embodiment can include one or more leakage flow-through channels (400) that are inserted into the insulation layer (200) at different positions of the insulation layer (200) to ensure that the liquefied gas leaked from the main barrier (100) surrounding the storage tank is completely discharged.

[0045] The partial auxiliary barrier (500) of the insulation system for a liquefied gas storage tank according to the present embodiment can be configured in the form of a pipe that communicates with the leakage flow-through channel (400). Specifically, the partial auxiliary barrier (500) according to the present invention can be connected to the leakage flow-through channel (400) at one end and form a gas opening (510) at the other end, so that the leaked liquefied gas introduced into the partial auxiliary barrier (500) through the leakage flow-through channel (400) can be completely vaporized when flowing towards the gas opening (510). Specifically, the partial auxiliary barrier (500) can be connected to the leakage flow-through channel (400) in a liquid-tight manner by one of welding, threaded connection or bolt connection. Since the leakage flow-through channel (400) is manufactured in the form of a small-diameter pipe, the partial auxiliary barrier (500) can also be manufactured in the form of a small-diameter pipe.

[0046] In addition, the partial auxiliary barrier (500) can be manufactured in the form of a long pipe to ensure that the leaked liquefied gas discharged from the leakage flow-through channel (400) is completely vaporized. That is, by increasing the length of the pipe through which the leaked liquefied gas flows, the area available for heat transfer can be increased. For this purpose, as Figure 2 shown, the partial auxiliary barrier (500) can adopt various shapes.

[0047] The dimensions of the partial auxiliary barrier (500), including length, diameter and internal surface area, can be determined according to factors such as the diameter of the leakage flow-through channel (400), the size of the storage tank, and the loading capacity of the storage tank.

[0048] In addition, the partial auxiliary barrier (500) of the insulation system for a liquefied gas storage tank according to the present embodiment may be formed of a metal barrier material suitable for the characteristics of liquefied gas, preferably a material that can easily transfer heat due to its metallic properties.

[0049] As Figure 1 shown, the partial auxiliary barrier (500) of the insulation system for a liquefied gas storage tank according to the present embodiment may be partially formed into a curved portion, such as an "L" shape. This feature enables a structure that allows the partial auxiliary barrier (500) to be stably fixed to the leakage flow-through channel (400) and supported by the leakage flow-through channel (400). However, it should be understood that the position and shape of the partial auxiliary barrier (500) do not need to be particularly limited and may be appropriately changed or modified to conform to the structural characteristics of the ship.

[0050] Referring Figure 2 to (a), (b), (c), (d), (e) and (f) of Figure 2 (a) of Figure 2 (b) of Figure 2 (c) of Figure 2 (d) of Figure 2 (e) of Figure 2 (f) of

[0051] Accordingly, since the partial auxiliary barrier (500) according to the present invention is configured in the form of a pipe, the need for a drip tray that is usually installed to collect leaked liquefied gas can be eliminated, thereby effectively solving various problems related to the installation of the drip tray (e.g., unnecessary use of space in a ship, etc.).

[0052] In addition, since the partial auxiliary barrier (500) according to the present invention is configured in the form of a pipe, the structure is significantly simplified compared to a typical drip tray, and an insulation system that is not restricted by space can be achieved. Specifically, since an additional insulation device needs to be installed to prevent the cooling of nearby wall surfaces, a typical drip tray needs to be installed in a limited space, while the pipe-type partial auxiliary barrier (500) according to the present invention can be installed in a space-saving manner due to the structure that allows the partial auxiliary barrier (500) to be stably fixed to the leakage flow-through channel (400) and supported by it, thereby enabling an insulation system that is not restricted by space.

[0053] As described above, the isolation system for a liquefied gas storage tank according to this embodiment is configured such that any liquefied gas introduced into the partial auxiliary barrier (500) is completely vaporized before flowing toward the gas opening (510) formed at the other end of the partial auxiliary barrier (500), and then discharged to the outside. Here, the amount of vaporized liquefied gas can be estimated by calculating the heat of the liquefied gas penetrating into the introduced partial auxiliary barrier (500) using the following equation:

[0054]

[0055] In the above equation, Q is the heat penetrating into the partial auxiliary barrier (500), d is the density of the leaked liquefied gas, V is the volume of the leaked liquefied gas, and L is the latent heat of the leaked liquefied gas. By using this equation, the amount of heat penetration required to completely vaporize the liquefied gas introduced into the auxiliary barrier can be calculated. In addition, based on the calculated required heat penetration amount, the amount of completely vaporized liquefied gas can be estimated, and the diameter or length of the partial auxiliary barrier (500) allowing the liquefied gas to pass through can be determined.

[0056] In addition, the partial auxiliary barrier (500) of the isolation system for a liquefied gas storage tank according to this embodiment can provide a pressure relief valve at its other end to block or control the flow of liquefied gas through the partial auxiliary barrier (500). In addition, the degree to which the pressure relief valve opens can be adjusted using the above equation. Here, the pressure relief valve can be configured to be controlled based on the amount of liquefied gas introduced into the partial auxiliary barrier (500).

[0057] The isolation system for a liquefied gas storage tank according to this embodiment can further include a connecting pipe to completely collect the liquefied gas leaking from the main barrier (100).

[0058] Refer to Figure 3, the leakage flow-through channel (400) and the partial auxiliary barrier (500) of the isolation system for the liquefied gas storage tank according to this embodiment can be arranged at the bottom of the storage tank. In particular, the leakage flow-through channel (400) can be arranged at multiple positions at the bottom of the storage tank to completely collect the liquefied gas leaking from the storage tank. In addition, the isolation system for the liquefied gas storage tank according to this embodiment can include one or more leakage flow-through channels (400) and one or more connecting pipes (610), and each connecting pipe (610) connects a pair of adjacent leakage flow-through channels (400). The connecting pipe (610) can be configured to connect multiple leakage flow-through channels (400) in series and transport the liquefied gas to the partial auxiliary barrier (500) configured downstream thereof. The leaked liquefied gas discharged through one leakage flow-through channel (400) is partially vaporized when passing through the connecting pipe (610) connected to another adjacent leakage flow-through channel (400), and is completely vaporized when passing through the partial auxiliary barrier (500) located at the farthest downstream among the multiple leakage flow-through channels (400), and then is finally discharged to the outside.

[0059] Figure 4 is a schematic diagram showing the coupling structure of the isolation system for the liquefied gas storage tank according to another embodiment of the present invention. In the embodiments described below, the same or similar components as those in the above embodiments will be denoted by the same or similar reference numerals, and the detailed description thereof will be omitted. Please refer to the above description.

[0060] The leakage flow-through channel (400) of the isolation system for the liquefied gas storage tank according to this embodiment can be coupled to the corresponding connecting pipe (620). Specifically, the isolation system for the liquefied gas storage tank according to this embodiment can include one or more leakage flow-through channels (400), and each leakage flow-through channel (400) is coupled to the corresponding connecting pipe among one or more connecting pipes (620). In addition, the connecting pipes (620) connected to each leakage flow-through channel (400) can be integrated into a single pipeline to be connected to the partial auxiliary barrier (500). Alternatively, the leaked liquefied gas discharged from multiple leakage flow-through channels (400) can be collected in a separate leakage fluid collection device 630 and then transported to the partial auxiliary barrier (500).

[0061] Therefore, in this embodiment, the leaked liquefied gas discharged through the leakage flow-through channel (400) can be partially vaporized when being transported to the partial auxiliary barrier (500) through the connecting pipe (620), and can be completely vaporized through heat exchange when passing through the partial auxiliary barrier (500), and then is finally discharged to the outside of the hull through the gas opening (510).

[0062] In addition to the above embodiments, the present invention also includes all embodiments conceived by the combination of two or more embodiments or the combination of one or more embodiments and known technologies.

[0063] Although some embodiments have been described herein, it should be understood that these embodiments are provided for illustrative purposes only and should not be construed in any way as limiting the present invention, and those of ordinary skill in the art can obtain various modifications, variations, changes, and equivalent embodiments without departing from the spirit of the invention.

[0064] It should be understood that any minor variations or changes to the present invention are included within the scope of the invention, and the scope of protection of the invention will be defined by the appended claims.

Claims

1. An isolation system for a liquefied gas storage tank, comprising: A main barrier, contacting the liquefied gas; An isolation layer, disposed outside the main barrier; A leakage flow path, formed between the main barrier and the isolation layer and having an outlet through which the liquefied gas leaking from the main barrier flows; A leakage flow through-channel, inserted into the isolation layer, connected to the leakage flow path, and allowing the leaked liquefied gas to pass therethrough; And A partial auxiliary barrier, communicating with the leakage flow through-channel and configured in the form of a pipe, wherein, in the case of a leakage in the main barrier, the leaked liquefied gas is completely vaporized when passing through the partial auxiliary barrier configured in the form of a pipe.

2. The isolation system according to claim 1, wherein one end of the partial auxiliary barrier is connected to the leakage flow through-channel and has a gas opening formed at the other end to discharge the liquefied gas vaporized within the partial auxiliary barrier.

3. The isolation system according to claim 1, wherein the partial auxiliary barrier is configured in the form of a pipe having an internal space and has a shape selected from a straight shape, a curved shape, a zigzag shape, a spring shape, and a radial shape to increase the length.

4. The isolation system according to claim 1, wherein the partial auxiliary barrier is connected to the leakage flow through-channel in a liquid-tight manner by one of welding, threaded connection, or bolt connection.

5. The isolation system according to claim 1, wherein the leakage flow through-channel includes one or more leakage flow through-channels, and the one or more leakage flow through-channels are disposed at different positions of the liquefied gas storage tank and communicate with the partial auxiliary barrier.

6. The isolation system according to claim 1, wherein the leakage flow through-channel includes one or more leakage flow through-channels, The isolation system further includes: a connecting pipe, serially connecting one leakage flow through-channel with an adjacent another leakage flow through-channel, and the partial auxiliary barrier is connected to the most downstream one of the leakage flow through-channels serially connected to each other by the connecting pipe.

7. The isolation system according to claim 1, wherein the leakage flow through-channel includes one or more leakage flow through-channels, and The isolation system further includes: a connecting pipe, connecting a corresponding one of the leakage flow through-channels to the partial auxiliary barrier.

8. The isolation system according to claim 1, wherein the partial auxiliary barrier includes a pipe formed of a metal that can serve as a barrier material suitable for the liquefied gas.

9. A ship, comprising the isolation system of the liquefied gas storage tank according to any one of claims 1 to 8.

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