KR20210085637A - Gas dome structure and liquefied gas storage tank having the same - Google Patents

Abstract

Disclosed are a gas dome structure installed in a liquefied gas storage tank capable of storing liquefied gas and a liquefied gas storage tank having the gas dome structure. The gas dome structure may comprise: a gas dome body (22) installed on the ceiling of the liquefied gas storage tank; a pipe (24) disposed to pass through the inside of the gas dome body (22) and communicating the inside and the outside of the liquefied gas storage tank; and a heat blocking device (30) attached to the pipe (24) to block the transfer of cold air from the liquefied gas accommodated in the liquefied gas storage tank to the inside of the gas dome body (22).

Description

Gas dome structure and liquefied gas storage tank equipped therewith {GAS DOME STRUCTURE AND LIQUEFIED GAS STORAGE TANK HAVING THE SAME}

The present invention is a gas dome structure installed so that a pipe for processing boil-off gas in a liquefied gas storage tank for storing liquefied gas such as liquefied natural gas (LNG) or liquefied petroleum gas (LPG) can be disposed and the gas It relates to a liquefied gas storage tank having a dome structure.

Natural gas is transported in gaseous state through onshore or offshore gas pipelines, or stored in liquefied gas carriers in a liquefied state and transported to remote consumers.

For example, liquefied gas such as LNG (Liquefied Natural Gas) or LPG (Liquefied Petroleum Gas) is obtained by cooling natural gas or petroleum gas to a cryogenic temperature (approximately -162°C in the case of LNG), and its volume It is greatly reduced, so it is very suitable for storage and transportation.

Liquefied gas carriers, such as LNG carriers, are for loading and unloading liquefied gas to and from customers on land or at sea by navigating the sea, and for this purpose, storage tanks (often called 'cargo holds') that can withstand cryogenic temperatures of liquefied gas ') is included. As an example of an offshore structure provided with a storage tank capable of storing liquefied gas in a cryogenic state, a ship such as an LNG RV (Regasification Vessel), an LNG FSRU (Floating Storage and Regasification Unit), an LNG FPSO (Floating, Production, Storage and Off-loading), BMPP (Barge Mounted Power Plant), FSPP (Floating and Storage Power Plant), and the like.

The LNG RV is an LNG regasification facility installed on a liquefied natural gas carrier that can sail and float on its own. The LNG FSRU is a structure that stores liquefied natural gas unloaded from an LNG carrier in a storage tank at sea far from land, then vaporizes the liquefied natural gas as needed and supplies it to onshore consumers. It is a structure used to directly liquefy and store in a storage tank after refining it, and to transfer the LNG stored in the storage tank to an LNG carrier when necessary. BMPP is a structure used to produce electricity at sea by mounting power generation facilities on barges, and FSPP is an offshore plant that produces electricity by mounting power generation facilities and storage tanks on structures floating on the sea.

In recent years, as environmental regulations regulating the emission of nitrogen and sulfur oxides have been strengthened, the number of LNG-fueled ships (LNG-powered ships) is being built, and as a type of LNG carrier, LNG bunkering is used to supply LNG to LNG-powered ships. Vessels (LNG BV) are also needed and are being built. The same storage tank as the LNG carrier is also used in these LNG bunkering vessels.

In this way, in marine structures such as LNG carriers, LNG BV, LNG RV, LNG FPSO, LNG FSRU, BMPP, and FSPP that transport or store liquid cargo such as LNG at sea, for storing LNG, which is a liquid cargo, in a cryogenic state A storage tank is installed.

Liquefied gas such as LNG stored in the storage tank is inevitably vaporized by heat continuously transmitted from the outside, even though the storage tank is surrounded by an insulating wall. Taking natural gas as an example, since the liquefaction temperature of natural gas is a cryogenic temperature of about -162 degrees Celsius at normal pressure, liquefied natural gas is evaporated even if its temperature is slightly higher than the liquefaction temperature at normal pressure.

Gas generated by vaporizing liquefied gas is called boil-off gas. BOG is an unavoidable phenomenon that comes out of the storage process of liquefied gas, and various methods have been devised to recycle the BOG without throwing it away. The treatment of boil-off gas is a very important problem in the storage of liquefied gas. The generated BOG may cause safety problems by increasing the pressure in the liquefied gas storage tank and may cause structural problems by accelerating the flow of liquefied gas according to the fluctuation of the ship. need to be dealt with.

Conventionally, in order to treat BOG in the liquefied gas storage tank, the BOG is discharged to the outside of the liquefied gas storage tank and incinerated in a boiler or gas combustion unit, etc., and the BOG is discharged to the outside of the liquefied gas storage tank to be recycled. A method of re-liquefying it through a liquefaction device and returning it back to a liquefied gas storage tank, a method of using boil-off gas as fuel in a ship's propulsion engine or power generation engine, etc. It has been known to utilize the methods of suppression, etc. alone or in combination.

In order to process BOG using these various methods, a means for discharging BOG to the outside of the liquefied gas storage tank must be installed in the liquefied gas storage tank.

A gas dome structure disposed on a pipe or the like for discharging boil-off gas from the liquefied gas storage tank is generally formed on the ceiling of the liquefied gas storage tank.

A plurality of pipes may be disposed in the gas dome structure, and these pipes discharge the boil-off gas generated in the inside of the liquefied gas storage tank to the outside of the liquefied gas storage tank, or a liquid state from the outside to the inside of the liquefied gas storage tank It can be used to introduce natural gas from

As such, the gas dome structure (and the pipes disposed therein) is installed to pass through the insulating wall and the sealing wall of the liquefied gas storage tank to connect the inside and the outside of the liquefied gas storage tank. Although the insulating wall and sealing wall are installed in the gas dome structure by extending the insulating wall and sealing wall of the liquefied gas storage tank, cold air is transferred from the liquefied gas contained in the liquefied gas storage tank to the gas dome structure, and the gas dome Leaks frequently occur on the main surface of hatches installed in structures.

The present invention, made in consideration of this, provides a gas dome structure and liquefaction having the same to block the cold air transmitted from the inside of the liquefied gas storage tank to the gas dome structure side as much as possible by installing a heat blocking device at the lower end of the gas dome structure. It is intended to provide a gas storage tank.

According to an aspect of the present invention, as a gas dome structure installed in a liquefied gas storage tank capable of storing liquefied gas, a gas dome body installed on the ceiling of the liquefied gas storage tank, and the gas dome body to pass through A pipe disposed to communicate the inside and the outside of the liquefied gas storage tank, and a heat blocking device attached to the pipe to block the transfer of cold air from the liquefied gas accommodated in the liquefied gas storage tank to the inside of the gas dome body A gas dome structure comprising a may be provided.

In one embodiment, the heat blocking device may be disposed on the same plane as the primary sealing wall of the liquefied gas storage tank.

In one embodiment, the heat blocking device may include a fixing member fixedly mounted to the pipe, and a blocking member coupled to the fixing member to block cold air from the liquefied gas.

In one embodiment, the plurality of fixing members may be installed at regular intervals from each other on the outer circumferential surface of the pipe.

In an embodiment, the blocking member may include a flat plate portion having a sectoral shape, and a bent portion bent from one edge of the flat portion and coupled to the fixing member.

In one embodiment, a plurality of the blocking members are disposed around the pipe, and the flat portions of the blocking members adjacent to each other may partially overlap each other.

In one embodiment, the flat plate portion and the bent portion may be formed integrally. Further, in one embodiment, the flat plate portion and the bent portion may be formed by bonding separate parts.

In one embodiment, the heat blocking device is installed between the pipe and the gas dome body, there may be a gap between the heat blocking device and the gas dome body.

According to another aspect of the present invention, there is provided a liquefied gas storage tank capable of storing liquefied gas, and a sealing wall and an insulating wall installed to prevent leakage of the contained liquefied gas and block heat transfer from the outside, and liquefied gas and a gas dome structure installed in the liquefied gas storage tank to form a passage for discharging boil-off gas generated from the liquefied gas storage tank to the outside of the liquefied gas storage tank, wherein the gas dome structure is, the ceiling of the liquefied gas storage tank A gas dome body installed in a gas dome body, a pipe disposed to pass through the inside of the gas dome body to communicate the inside and the outside of the liquefied gas storage tank, and the liquefied gas attached to the pipe and accommodated in the liquefied gas storage tank. A liquefied gas storage tank including a heat blocking device for blocking the cold air from being transmitted to the inside of the gas dome body may be provided.

According to the present invention, by installing a heat blocking device at the lower end of the gas dome structure, the gas dome structure and liquefied gas storage having the same can suppress the transfer of cold air from the inside of the liquefied gas storage tank to the gas dome structure side as much as possible. A tank may be provided.

According to the gas dome structure of the present invention, since it includes a heat blocking device installed at approximately the same height as the primary sealing wall stacked and installed inside the liquefied gas storage tank, cold air from the liquefied gas accommodated in the liquefied gas storage tank It is possible to suppress the transmission of the gas to the inner space of the gas dome structure, it is possible to reduce the possibility of leakage around the hatch of the gas dome structure.

Furthermore, according to the gas dome structure of the present invention, it is possible to alleviate the freezing phenomenon that may occur on the outer surface of the gas dome structure.

1 is a side cross-sectional view showing a gas dome structure according to an embodiment of the present invention together with a part of a liquefied gas storage tank.
2 is a perspective view of a main part of a gas dome structure according to an embodiment of the present invention as viewed from below.
FIG. 3 is a view similar to FIG. 2 , and is a perspective view illustrating a state in the middle of assembling a heat shielding device included in the gas dome structure.
4A to 4C are plan cross-sectional views of a gas dome structure according to an embodiment of the present invention, and are views for explaining a method of assembling a heat shielding device included in the gas dome structure.

Hereinafter, the configuration and operation according to an embodiment of the present invention will be described in detail with reference to the drawings. In addition, the following embodiments may be modified in various other forms, and the scope of the present invention is not limited to the following embodiments.

1 is a gas dome structure according to an embodiment of the present invention is shown together with a part of the liquefied gas storage tank. 2 and 3 are a perspective view of a gas dome structure according to an embodiment of the present invention as viewed from below, and FIG. 2 shows an overall form of a heat shielding device assembled to the gas dome structure, and FIG. The state during assembly of the blocking device is shown.

As shown in FIG. 1, the gas dome structure according to an embodiment of the present invention includes a gas dome body 22 installed on the ceiling of a liquefied gas storage tank, and the gas dome body 22 to pass through the inside. A pipe 24 that is disposed to communicate the inside and the outside of the liquefied gas storage tank, and the cold air from the liquefied gas attached to the pipe 24 and accommodated in the liquefied gas storage tank into the inside of the gas dome body 22 It includes a heat blocking device 30 that blocks the transmission.

The gas dome body 22 may have a substantially cylindrical shape with a closed top. 1 schematically shows a gas dome body 22, and the material and shape of the gas dome body 22 do not limit the present invention. In addition, a heat insulating wall and a sealing wall may be laminatedly installed inside, outside, or both inside and outside the gas dome body 22, and in FIG. 1, for convenience of explanation, an insulating wall installed around the gas dome body 22 and The illustration of the sealing wall is omitted. In addition, since the gas dome body 22 can be used with any known type, further detailed description thereof will be omitted.

1 shows only the insulating wall and the sealing wall of the liquefied gas storage tank. In more detail, the liquefied gas storage tank includes a secondary insulating wall 15 laminated and installed on the hull structure wall 11 , and a secondary sealing wall 14 laminated and installed on the secondary insulating wall 15 , and , it may include a primary insulating wall 13 laminated and installed on the secondary sealing wall 14 , and a primary sealing wall 12 laminated and installed on the primary insulating wall 13 . The primary and secondary insulating walls 13 and 15 and the primary and secondary sealing walls 12 and 14 are formed of various materials, dimensions, and shapes according to the type of the Cargo Containment System (CCS). It can be manufactured, and any known one can be used for manufacturing a liquefied gas storage tank, so a further detailed description will be omitted.

In addition to the above-described pipe 24, various pipes (not shown) that are disposed to pass through the inside of the gas dome body 22 and communicate the inside and the outside of the liquefied gas storage tank may exist. In FIG. 1, only the pipe 24 is shown for convenience of description. One end of the pipe 24 (the lower end as seen in Fig. 1) is located inside the liquefied gas storage tank, and the other end (the upper end as seen in Fig. 1) of the pipe 24 is located outside the liquefied gas storage tank. can do.

The heat shield 30 may be installed in the pipe 24 . The height at which the heat blocking device 30 is installed may correspond to the height at which the primary sealing wall 12 of the liquefied gas storage tank is located, as shown in FIG. 1 . That is, the heat shielding device 30 and the primary sealing wall 12 may be disposed on the same plane.

2 and 3 , the heat shielding device 30 is disposed between a fixing member 32 fixedly mounted to the pipe 24 and the pipe 24 and the gas dome body 22 . and a blocking member 34 coupled to the fixing member 32 so as to extend in the horizontal direction.

The fixing member 32 may be fixedly mounted on the outer circumferential surface of the pipe 24 by welding or the like. 2 to 4c, a plurality of fixing members 32 may be installed on the outer circumferential surface of the pipe 24 at regular intervals from each other. 2 to 4c, four fixing members 32 are installed on the outer circumferential surface of the pipe 24 at an angular interval of approximately 90 degrees, but the number of fixing members 32 may be 3 or less or 5 or more.

In the fixing member 32 , for coupling with the blocking member 34 , one or more coupling holes through which the fastening member 40 such as a bolt passes may be formed.

The blocking member 34 includes a flat plate portion 36 having a sectoral shape that extends from the pipe 24 toward the gas dome body 22 , and is bent substantially vertically from one edge of the flat plate portion 36 . A portion 38 may be included.

In FIG. 2, four blocking members 34 are shown, and in this case, the adjacent flat plate parts 36 are formed to partially overlap each other. When the heat shielding device 30 includes, for example, four blocking members 34 , the flat portion 36 of each blocking member 34 has a sectoral shape with a central angle greater than 90 degrees. That is, the flat plate portion 36 of the blocking member 34 may have a sectoral shape having a central angle greater than a value obtained by dividing 360 degrees by the number of blocking members 34 included in the heat blocking device 30 . . When the central angle is determined in this way, one blocking member 34 can be supported by two fixing members 32 (see FIGS. 4B and 4C ).

The flat plate part 36 can block the transfer of cold air from the inside of the liquefied gas storage tank to the inside of the gas dome body 22 , and the bent part 38 is the flat plate part 36 through the fixing member 32 . It can be fixed against the pipe (24). The bent portion 38 may have a length extending over the entire edge of one side of the flat plate portion 36 or may be formed with a length extending over a portion of the flat plate portion 36 . The flat plate portion 36 and the bent portion 38 may be formed integrally by bending a metal plate, or may be formed by joining separate parts by welding or the like.

In the bent portion 38 of the blocking member 34 , one or more through-holes through which the fastening member 40 such as a bolt passes may be formed for coupling with the fixing member 32 . The coupling hole formed in the fixing member 32 and the through hole formed in the bent portion 38 of the blocking member 34 are aligned so that the coupling member 40 can pass when coupled.

The flat plate part 36 of the blocking member 34 may not contact the inner peripheral surface of the gas dome body 22 , and a gap may exist between the flat plate part 36 and the gas dome body 22 . Various pipes (not shown) can pass through this gap. If necessary, a cutout (not shown) may be formed in the flat plate portion 36 to secure passages such as various pipes. The cutout does not have to be formed on the edge of the flat plate part 36 , but may be formed inside the flat plate part 36 so as to penetrate the flat plate part 36 .

4A to 4C are plan cross-sectional views of a gas dome structure according to an embodiment of the present invention, in which FIGS. 4A to 4C sequentially show a process of assembling the heat shielding device.

4A shows, for example, a state in which four fixing members 32 are fixedly mounted to the pipe 24 . As described above, the fixing members 32 are installed at regular intervals.

4B shows a state in which one blocking member 34 is coupled to one fixing member 32 . As described above, the coupling of the blocking member 34 and the fixing member 32 is formed in the through hole formed in the bent portion 38 of the blocking member 34 and the coupling hole formed in the fixing member 32 by the fastening member 40 . It can be done by inserting and fastening.

Figure 4c shows a state in which two blocking members 34 adjacent to each other are assembled. As described above, the blocking member 34 has a size that can be supported by the two fixing members 32 , and in this case, the bent portion 38 side of the blocking member 34 is directly connected to the fixing member 32 . By being coupled, it is supported by the fixing member 32, and the edge side of the flat plate portion 36 opposite to the bent portion 38 is supported by the fixing member 32 through another adjacent blocking member 34 (A in Fig. 4c). see section). That is, the edge portion of the flat plate portion 36 on the side of the bent portion 38 may be sandwiched between the fixing member 32 and the edge portion of the flat portion 36 on the opposite side of the bent portion 38 . If necessary, the flat portions 36 in contact with each other may be joined by, for example, welding.

On the other hand, each of the flat plate parts 36 may have a size such that they do not overlap each other during assembly, and the edge end surfaces can contact each other on the same plane. In this case, the adjacent flat plate parts 36 are, for example, welded to each other. may be joined to form a single disk shape as a whole.

1, the gas dome body 22 is shown to extend only upward from the hull structure wall 11, but this is only an example, and the lower end of the gas dome body 22 is the primary sealing wall of the liquefied gas storage tank ( 12) may be extended to the installed position.

In the above description, it is expressed that "the flat portion 36 of the blocking member 34 extends from the pipe 24 toward the gas dome body 22", but the lower end of the gas dome body 22 is the primary sealing wall. In the case where it does not extend to the installation position of (12), the above expression is "the flat portion 36 of the blocking member 34 extends horizontally from the pipe 24 toward the primary sealing wall 12". should be considered

That is, regardless of the vertical length of the gas dome body 22 , the blocking member 34 extends horizontally at the same height as the primary sealing wall 12 , thereby blocking the transfer of cold air to the internal space of the gas dome structure. can be installed to

In addition, in the above description, the flat plate portion 36 of the blocking member 34 and the fixing member 32 are fastened by a fastening member 40 such as a bolt, for example, as an example, but the flat plate portion of the blocking member 34 is described as an example. Of course, the part 36 and the fixing member 32 may be connected through another coupling method such as welding or fitting, for example.

As described above, the embodiment of the present invention has been described with reference to the illustrated drawings, but the present invention is not limited by the embodiments and drawings described above, and within the scope of the claims, it is common in the technical field to which the present invention pertains. It goes without saying that various modifications and variations may be made by those having knowledge.

11: hull structural wall, 12: primary sealing wall, 13: primary insulating wall, 14: secondary sealing wall, 15: secondary insulating wall, 22: gas dome body, 24: pipe, 30: heat shielding device, 32: fixing member, 34: blocking member, 36: flat plate portion, 38: bent portion, 40: fastening member.

Claims (10)

A gas dome structure installed in a liquefied gas storage tank capable of storing liquefied gas,
a gas dome body installed on the ceiling of the liquefied gas storage tank;
a pipe disposed to pass through the inside of the gas dome body and communicating the inside and the outside of the liquefied gas storage tank;
A heat blocking device attached to the pipe to block the transfer of cold air from the liquefied gas accommodated in the liquefied gas storage tank to the inside of the gas dome body
comprising, a gas dome structure. The method according to claim 1,
The heat blocking device is disposed on the same plane as the primary sealing wall of the liquefied gas storage tank, a gas dome structure. The method according to claim 1,
The heat blocking device includes a fixing member fixedly mounted to the pipe, and a blocking member coupled to the fixing member to block cold air from the liquefied gas. 4. The method according to claim 3,
A gas dome structure in which a plurality of fixing members are installed at regular intervals from each other on the outer circumferential surface of the pipe. 4. The method according to claim 3,
The blocking member includes a flat plate portion having a sectoral shape, and a bent portion formed to be bent from one edge of the flat portion and coupled to the fixing member, the gas dome structure. 6. The method of claim 5,
A plurality of the blocking members are disposed around the pipe, and the flat portions of the blocking members adjacent to each other partially overlap each other. 6. The method of claim 5,
The flat portion and the bent portion are formed integrally, the gas dome structure. 6. The method of claim 5,
The flat portion and the bent portion are formed by bonding separate parts, a gas dome structure. The method according to claim 1,
The heat shielding device is installed between the pipe and the gas dome body, and a gap exists between the heat shielding device and the gas dome body. As a liquefied gas storage tank capable of storing liquefied gas,
A sealing wall and an insulating wall installed to prevent leakage of the contained liquefied gas and to block heat transfer from the outside;
and a gas dome structure installed in the liquefied gas storage tank to form a passage for discharging boil-off gas generated from the liquefied gas to the outside of the liquefied gas storage tank,
The gas dome structure includes a gas dome body installed on the ceiling of the liquefied gas storage tank, a pipe disposed to pass through the inside of the gas dome body and communicating the inside and the outside of the liquefied gas storage tank, and the pipe A liquefied gas storage tank comprising a thermal blocking device attached to block the transfer of cold air from the liquefied gas accommodated in the liquefied gas storage tank to the inside of the gas dome body.

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