KR20220015853A - Liquefied Gas Tank and ship having the same - Google Patents

Abstract

The present invention relates to a liquefied gas storage tank and a ship including the same, comprising: a storage tank provided on a hull in which liquefied gas is stored; and a liquefied gas transport line connected to the storage tank to supply and/or discharge liquefied gas to the storage tank, wherein the liquefied gas transport line passes through one surface of the storage tank close to the hull, thereby capable of preventing the risk of cryogenic damage and explosion caused by liquefied gas leakage.

Description

Liquefied gas storage tank and ship including same {Liquefied Gas Tank and ship having the same}

The present invention relates to a liquefied gas storage tank and a ship including the same.

In general, natural gas (hereinafter referred to as NG) is produced in a state of liquefied natural gas (Liquefied Natural Gas, hereinafter referred to as LNG) liquefied at a cryogenic temperature at the production site and then transported over a long distance to the destination by an LNG carrier. After that, the LNG is regasified and supplied to consumers through a floating storage and regasification unit (FSRU) or an onshore unloading terminal.

In order to transport natural gas, the liquefied gas carrier must be equipped with a liquefied gas storage tank capable of storing and storing the liquefied gas liquefied in a cryogenic state. Because the conditions required for such an LNG storage tank are very strict, LNG has a vapor pressure higher than atmospheric pressure and has a boiling temperature of about -162°C. It should be made of durable materials such as aluminum steel, stainless steel, 35% nickel steel, etc.

A liquefied gas transfer line for supplying or discharging liquefied gas to such a liquefied gas storage tank is connected, and is generally connected through the dome of the upper part of the liquefied gas storage tank.

Accordingly, as the liquefied gas transfer line penetrates the foam insulation added to the outer surface of the LNG storage tank, cracks occur due to the difference in expansion rates between the steel material and the insulation material during heat shrinkage.

In addition, since the liquefied gas pump (supply pump) is installed inside the liquefied gas storage tank, there is a problem in that all of the liquefied gas in the storage tank must be emptied and inerted for maintenance of the liquefied gas pump.

The present invention was created to solve the problems of the prior art as described above, and an object of the present invention is to connect the liquefied gas transport line to the lower side of the storage tank, reducing the equipment that supported the connection line, etc. on the upper part of the storage tank, It is to provide a liquefied gas storage tank capable of preventing the risk of cryogenic damage and explosion caused by liquefied gas leakage, and a ship including the same.

A liquefied gas storage tank according to an aspect of the present invention is connected to a storage tank and the storage tank provided in the hull in which liquefied gas is stored, and supplies the liquefied gas to the storage tank or liquefied gas for discharging the liquefied gas from the storage tank. a gas transport line, wherein the storage tank is a pressure vessel for storing liquefied gas at high pressure, and the liquefied gas transport line is provided to pass through the lower portion of the storage tank, and is provided below the liquefied gas transport line and a drip tray for accommodating the leaking liquefied gas.

Specifically, it is provided on the liquefied gas transport line and includes a valve part for controlling the amount of liquefied gas transferred along the liquefied gas transport line, and the drip tray is provided on the liquefied gas transport line, and the drip tray includes the valve part to accommodate the liquefied gas leaking from the valve part. It may be provided below.

Specifically, it may include a accommodating part for accommodating the valve part and the drip tray.

Specifically, it may include a re-liquefaction device for returning the reliquefied gas to the accommodating unit by heat-exchanging the boil-off gas generated in the accommodating part with the refrigerant.

Specifically, the valve unit may include a valve handle provided to partially protrude to the outside of the receiving unit to adjust the opening degree.

Specifically, it may include a liquefied gas drain line extending from the drip tray in the direction of the overboard of the hull to discharge the leaked liquefied gas accommodated in the drip tray.

Specifically, it may include a hull water film part for spraying water in a direction in which the liquefied gas is discharged from the liquefied gas drain line.

A ship according to an aspect of the present invention is characterized in that it is a ship having the liquefied gas storage tank.

In the liquefied gas storage tank and the ship including the same according to the present invention, the liquefied gas transport line is connected from the lower side of the storage tank, and the equipment that supports the liquefied gas transport line at the upper part of the storage tank is unnecessary, so material costs can be reduced. In addition to the drip tray, leakage of liquefied gas is accommodated secondarily to prevent the risk of cryogenic damage and explosion due to leakage of liquefied gas, thereby improving safety.

1 is a view showing a liquefied gas storage tank according to a first embodiment of the present invention;
2 is a view showing a liquefied gas storage tank according to a second embodiment of the present invention;
3 is a view showing a liquefied gas storage tank according to a third embodiment of the present invention;
4 is a view showing a liquefied gas storage tank according to a fourth embodiment of the present invention;
5 is a view showing a liquefied gas storage tank according to a fifth embodiment of the present invention;
6 and 7 are views showing a liquefied gas storage tank according to a sixth embodiment of the present invention.

The objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments taken in conjunction with the accompanying drawings. In the present specification, in adding reference numbers to the components of each drawing, it should be noted that only the same components are given the same number as possible even though they are indicated on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. For reference, in the present specification below, liquefied gas may be used to encompass all gas fuels generally stored in a liquid state, such as LNG or LPG, ethylene, ammonia, etc., and is not in a liquid state by heating or pressurization. The case may also be expressed as liquefied gas for convenience. This can be applied to boil-off gas as well.

In addition, for convenience, LNG can be used to encompass both NG (Natural Gas) in a liquid state as well as NG in a supercritical state. have.

In addition, it should be noted that liquefied gas/evaporated gas in the present specification is classified based on the state inside the tank, and is not necessarily limited to liquid or gaseous due to the name.

The present invention includes a ship equipped with a liquefied gas storage tank to be described below. At this time, a ship is a concept that includes all gas carriers, merchant ships that transport cargo or people other than gas, FSRUs, FPSOs, bunkering vessels, and offshore plants, but note that it may be a liquefied petroleum gas carrier as an example.

1 is a view showing a liquefied gas transport line to a liquefied gas storage tank according to a first embodiment of the present invention, Figure 2 is a diagram showing a liquefied gas transport line to a liquefied gas storage tank according to a second embodiment of the present invention 3 is a view showing a liquefied gas transport line to a liquefied gas storage tank according to a third embodiment of the present invention, and FIG. 4 is a liquefied gas transport line to a liquefied gas storage tank according to a fourth embodiment of the present invention. 5 is a view showing a liquefied gas transport line to a liquefied gas storage tank according to a fifth embodiment of the present invention, and FIGS. 6 and 7 are a liquefied gas storage tank according to a sixth embodiment of the present invention. It is a diagram showing liquefied gas.

1 to 7, the liquefied gas storage tank according to an embodiment of the present invention is a storage tank 10, liquefied gas transport lines (L1, L2), a valve unit 20, and a drip tray 30. , a pump 40 , a liquefied gas drain line 50 , a hull water film part 60 , a receiving part 70 , a purging part 80 , and a re-liquefaction device 90 .

1 is a view showing a liquefied gas storage tank according to a first embodiment of the present invention.

Referring to FIG. 1 , the storage tank 10 is provided in the hull in which liquefied gas is stored. The storage tank 10 stores the liquefied gas as fuel to be supplied to the propulsion engine.

The storage tank 10 may be an independent type (SPB type, MOSS type) or a membrane type cargo tank that stores a large amount of liquefied gas at atmospheric pressure, and may be an independent type (Type C, pressure vessel type) for storing liquefied gas at high pressure.

The storage tank 10 may manage the liquefied gas stored therein at an appropriate level/pressure in consideration of the operating state of the vessel and the like. For example, the storage tank 10 may store the liquefied gas at about 10 bar, and an insulating structure may be provided on at least one side of the inside or the outside of the wall to prevent vaporization of the liquefied gas.

The storage tank 10 may be mounted on the upper deck in a ship, and is provided to be supported on the upper deck through a saddle. The storage tank 10 does not interfere with the components (manifold, etc.) for loading/unloading liquefied gas of the cargo tank on the upper deck, and may be disposed at a position that does not block the visibility during the navigation of the vessel. As an example, the storage tank 10 may be provided on the port side or starboard side of the bow on the upper deck.

Such a storage tank may be provided with a barrier for storing liquefied gas, and an insulating material stacked by spraying on the outside of the barrier.

In the conventional storage tank, a liquefied gas transfer line and a platform support are connected to the upper part, and the liquefied gas transfer line and the platform support are provided to pass through the insulating material constituting the storage tank, that is, foam insulation. . At this time, cracks occur due to the difference in the expansion rate between the steel material and the insulating material such as the liquefied gas transfer line and the platform support. can be connected

The liquefied gas transport lines L1 and L2 are connected to the storage tank 10 to supply liquefied gas to the storage tank 10 or discharge the liquefied gas from the storage tank 10 . Liquefied gas transport lines (L1, L2) are provided to pass through the lower portion of the storage tank (10).

The liquefied gas transport lines L1 and L2 may be provided with a valve 20 for opening the amount of liquefied gas. In addition, in order to prepare for leakage from the liquefied gas transport lines (L1, L2) or the valve unit 20, the drip tray 30 of the liquefied gas transport lines (L1, L2) is provided to provide the liquefied gas transport lines (L1, L2) Alternatively, the liquefied gas leaking from the valve unit 20 may be accommodated in the drip tray 30 . For this reason, although the liquefied gas transport lines L1 and L2 are provided below the storage tank 10, a cold box made of SUS (Stainless Steel) material may not be additionally provided by welding or the like.

The valve unit 20 is provided on the liquefied gas transport lines (L1, L2), and can adjust the amount of liquefied gas transferred along the liquefied gas transport lines (L1, L2). The valve unit 20 may be provided in the liquefied gas supply line (L1) and the liquefied gas discharge line (L2), respectively. A drip tray 30 capable of accommodating the liquefied gas leaking from the valve unit 20 may be provided below the valve unit 20 .

The drip tray 30 is provided below the liquefied gas transport lines L1 and L2 to accommodate the leaking liquefied gas. The drip tray 30 is preferably made of a material that can prevent corrosion, such as SUS (Stainless Steel) material. The drip tray 30 may be provided below the valve part 20 to accommodate the liquefied gas leaking from the valve part 20 .

For example, the drip tray 30 leaks from at least one of the liquefied gas transport lines L1 and L2 and the valve unit 20, and from at least one of the liquefied gas transport lines L1 and L2 and the valve unit 20. Can accommodate liquefied gas.

The drip tray 30 may be configured to extend to a relatively large area to maintain the same accommodating volume as compared to when the height of the outer circumferential surface is high in a narrow area, and to lower the height of the outer circumferential surface.

The drip tray 30 may be designed based on a leak scenario for liquefied gas leakage. According to an example, the drip tray 30 may be formed to have an area and a height (depth) in which the amount of evaporation can be balanced with the amount of leakage by calculating the amount of leakage for a predetermined time. On the other hand, the drip tray 30 may include a vaporizer (not shown) in order to increase the evaporation amount of the liquefied gas.

2 is a view showing a liquefied gas storage tank according to a second embodiment of the present invention.

Hereinafter, the present embodiment will be mainly described on the points that are different from the previous embodiment, and the parts omitted from the description will be replaced with the previous content. Note that this also applies to other embodiments to be described later.

Referring to FIG. 2 , the storage tank 10 supplies liquefied gas to the inside of the storage tank 10 or liquefied gas in the storage tank 10 according to the required pressure of the demand receiving the liquefied gas to the demand. It may include a pump 40 for discharging. The pump 40 may selectively connect the storage tank 10 and the pump 40 according to the required pressure of the demand receiving the liquefied gas.

For example, the pump 40 is installed when the required pressure of the customer receiving the liquefied gas is higher than the internal pressure of the storage tank 10, and through the operation of the pump 40, the liquefied gas discharge line L2 through the storage tank ( 10) The liquefied gas inside can be discharged to the consumer.

Meanwhile, the pump 40 may omit the discharge process by the pump 40 when the required pressure of the demand receiving the liquefied gas is lower than the internal pressure of the storage tank 10 .

According to such a storage tank, the conventional pump (40, Supply Pump) provided inside the storage tank can be installed as an external type instead of a submersible type, thereby facilitating maintenance. In addition, it is possible to reduce costs by reducing the equipment for connecting the liquefied gas transfer line to the upper part of the storage tank, and there is no need to additionally install a platform for maintaining the pump, which can utilize space and reduce costs. It works.

3 is a view showing a liquefied gas storage tank according to a third embodiment of the present invention.

Referring to FIG. 3 , the liquefied gas drain line 50 extends from the drip tray 30 in the overboard direction of the hull S, and the leaked liquefied gas accommodated in the drip tray 30 is discharged. can be discharged

Here, when the drip tray 30 cannot be installed to satisfy the area and depth calculated through the virtual scenario (Maximum Leakage Scenario), the liquefied gas stored in the drip tray 30 is transferred through the liquefied gas drain line 50 . It can be drained to the outside of the hull (S).

The liquefied gas drain line 50 may be provided with a valve unit 20 , and may control the amount of liquefied gas discharged by the valve unit 20 . A hull water film part 90 (Water Curtain) may be provided to protect the shipside wall from the gas discharged from the liquefied gas drain line 50 .

The hull water film part 60 may be provided in the overboard direction in the same direction as the liquefied gas drain line 50 . The hull water film part 60 may spray water in a direction in which the liquefied gas is discharged from the liquefied gas drain line 50 .

The hull water film part 60 can protect the hull (S) from the liquefied gas that can be directed to the shipside of the hull by spraying the liquefied gas injected from the liquefied gas drain line 50 away from the hull (S). .

In this way, the hull water film part 60 prevents the liquefied gas ejected from the liquefied gas drain line 50 from being returned back to the hull (S), thereby preventing the risk of cryogenic damage and explosion due to leakage of liquefied gas. Safety is improved.

4 is a view showing a liquefied gas storage tank according to a fourth embodiment of the present invention.

Referring to FIG. 4 , the accommodating part 70 may selectively accommodate the valve part 20 and the drip tray 30 therein. For convenience of explanation, it will be described that the valve part 20, the drip tray 30, and a part of the liquefied gas transfer lines L1 and L2 are accommodated in the accommodating part 70.

The accommodating part 70 is provided to surround the valve part 20 and the drip tray 30 , and may accommodate liquefied gas leaking from the valve part 20 and the drip tray 30 therein. Meanwhile, the liquefied gas accommodated in the accommodating part 70 may include liquefied gas that evaporates from the drip tray 30 in addition to the liquefied gas leaking from the valve part 20 or the like.

The accommodating part 70 may be provided to prevent leakage (leakage) of the liquefied gas leaking from the valve part 20 and the drip tray 30 to the outside of the accommodating part 70 . The accommodating part 70 may be provided with a SUS material on a surface in contact with the liquefied gas to prevent corrosion, and may have a gas tight structure.

Accordingly, it is possible to protect the hull from the risk of liquefied gas leakage when the liquefied gas transfer lines (L1, L2) are connected to the lower side of the storage tank (10). That is, the accommodating part 70 accommodates the valve part 20 and the drip tray 30 therein, and can accommodate the liquefied gas leaking from the valve part 20 and the drip tray 30 .

This accommodating part 70 is able to protect the hull structure from the danger of leaked liquefied gas, and is effective as a tertiary barrier supplementing the drip tray 30 functioning as a secondary barrier. there is The accommodating part 70 may connect the purging part 80 to prevent explosion due to gas leakage.

The purging unit 80 may implement purging with respect to the portion in which the liquefied gas flows. The purging unit 80 may supply the purging gas to the liquefied gas supply line L1 , the liquefied gas discharge line L2 , the fuel tank 20 , the receiving unit 70 , and the like.

Here, the purging unit 80 may use nitrogen gas as a purge gas. In this case, the purging unit 80 may include a nitrogen generator (N2 generator) for generating nitrogen from air. Alternatively, when the purging gas is an inert gas, the purging unit 80 may be an inert gas generator (IGG) that generates an inert gas while burning fuel.

The reliquefaction device 90 may be connected to the receiving unit 70 to adjust the internal pressure of the receiving unit 70 . The reliquefaction device 90 heats the boil-off gas generated in the accommodating part 70 with the refrigerant to return the reliquefied gas to the accommodating part 70, thereby reducing the internal pressure of the accommodating part 70, thereby reducing the risk of explosion. can reduce

However, the boil-off gas generated in the accommodating part 70 is discharged to the outside through a vent mast, connected to the upper part of the storage tank 10 when necessary, or compressed by a compressor (not shown). may be supplied, and in this case, the reliquefaction device 90 may be omitted.

5 is a view showing a liquefied gas storage tank according to a fifth embodiment of the present invention.

Referring to FIG. 5 , the valve unit 20 may provide a valve handle 25 for adjusting the opening degree of the liquefied gas. The valve handle 25 may partially protrude to the outside of the accommodating part 70 to adjust the opening degree of the valve part 20 provided in the accommodating part 70 .

The valve handle 25 may extend from the valve unit 20 to the outside of the receiving unit 70 , and may operate the valve unit 20 from the outside of the receiving unit 70 . Accordingly, the valve handle 25 operates the valve part 20 without opening the accommodating part 70 to improve convenience and improve the airtightness of the accommodating part 70 .

The accommodating part 70 may be provided in the storage tank 10 in which the drip tray 30 is not provided. The accommodating part 70 may be wrapped to accommodate the liquefied gas transfer lines L1 and L2 and the valve part 20 therein. The accommodating part 70 may accommodate the liquefied gas leaking from the liquefied gas transfer lines L1 and L2 and the valve part 20 therein, and may include the function of the drip tray 30 .

The accommodating part 70 may have a structure in which the liquefied gas leaked from the valve part 20 does not leak to the outside of the accommodating part 70 . The accommodating part 70 is provided with a gas tight structure, and even if the liquefied gas is accommodated in the accommodating part 70 , it is possible to prevent leakage to the outside of the accommodating part 70 .

Since the accommodating part 70 accommodates the valve part 20 inside and is sealed, it is difficult to operate the valve part 20 from the outside of the accommodating part 70 . To this end, the valve handle 25 is partially protruded to the outside of the accommodating part 70 so that the valve part 20 can be operated even from the outside of the accommodating part 70 , so that the opening degree of the valve part 20 can be adjusted. The convenience is improved, and the sealing performance of the receiving part 70 can be maintained.

The receiving part 70 is able to protect the hull structure from the risk of leaked liquefied gas, and thus has an effect that can function as a secondary barrier.

6 and 7 are views showing a liquefied gas storage tank according to a sixth embodiment of the present invention.

Referring to FIGS. 6 and 7 , the liquefied gas transport lines L1 and L2 are provided in an inverted 'U' shape, and a loop-shaped bent part is disposed above the inside of the storage tank 10 .

The liquefied gas transport lines (L1, L2) may be provided so that the bent portion is exposed from the liquefied gas stored in the storage tank (10). The liquefied gas transport lines L1 and L2 may be provided to extend higher than the Top Level of the liquefied gas provided in the storage tank 10 so that the bent portion is partially exposed.

Here, the highest water level generally refers to the level of the amount of storage in which the liquefied gas is stored in the storage tank 10 . In general, the highest water level may be 98% according to the IGF Code, but in consideration of the density change according to the pressure/temperature change, it may be set within 98% in a high-pressure pressure vessel, but is not limited thereto, depending on the type of the storage tank (10) They may have different capacities depending on the

The liquefied gas supply line L1 may be branched into at least two or more as shown in FIG. 6 and pass through the lower portion of the storage tank 10 . The liquefied gas supply line L1 may be partially provided in parallel based on the flow of the liquefied gas.

The liquefied gas supply line (L1) is provided with a valve part 20 at the branching point. The liquefied gas supply line L1 passing under the storage tank 10 may have different lengths and may be provided inside the storage tank 10 .

For example, the liquefied gas supply line (L1) is arranged on the lower side of the storage tank 10, a first line for supplying liquefied gas from the lower surface of the storage tank (Bottom Filling), and a first line shorter than the first line is provided for the storage tank 10 ) may include a second line for providing (Top Filling) liquefied gas from the upper portion. The second line may eject the liquefied gas at a location where the outlet through which the liquefied gas is ejected is higher than the upper portion of the storage tank 10 , that is, the highest water level (Top Level). The liquefied gas supply line (L1) may be provided with a pump 40 in the liquefied gas supply line (L1) to supply the liquefied gas into the storage tank (10).

The liquefied gas discharge line L2 may pass through the lower side of the storage tank 10 as shown in FIG. 7 to discharge the liquefied gas inside the storage tank 10 to the outside of the storage tank 10 . The liquefied gas discharge line L2 may transfer the lower side liquefied gas inside the storage tank 10 . The liquefied gas discharge line L2 may be branched into at least two or more. The liquefied gas discharge line L2 may be partially provided in parallel based on the flow of the liquefied gas.

For example, the liquefied gas discharge line L2 may include a liquefied gas main discharge line that mainly discharges liquefied gas and a liquefied gas auxiliary discharge line that is used when it is difficult to use due to a malfunction or problem in the liquefied gas main discharge line. have. The liquefied gas discharge line L2 may include a valve 20 at a point where it joins from the outside of the storage tank 10 . The liquefied gas discharge line (L2) may be provided with a pump 40 for sucking the liquefied gas inside the storage tank 10 and transferring it to the liquefied gas discharge line (L2).

The pump 40 may be provided in the liquefied gas transport lines L1 and L2, and transfer the liquefied gas in the storage tank 10 to the liquefied gas transport lines L1 and L2. The pump 40 may be provided in a submerged type provided inside the storage tank 10 . The pump 40 may be provided in the liquefied gas supply line (L1) and/or the liquefied gas discharge line (L2). For example, the pump 40 will be described as being provided on the liquefied gas discharge line (L2). The pump 40 may transfer the liquefied gas in the storage tank 10 to the liquefied gas discharge line L2.

The pump 40 may pressurize the liquefied gas to a pressure lower than the required pressure of the propulsion engine and transfer the liquefied gas in the storage tank 10 to the propulsion engine. Here, the pump 40 is exemplified as a submersible type provided inside the storage tank 10 , but may also be provided outside the storage tank 10 by a user selectively selecting a pump type.

According to the present invention as described above, it is possible to connect the liquefied gas transport line to the lower portion of the storage tank, thereby reducing materials due to pipe extension and the like, thereby reducing costs. In addition, since the pump (LNG Supply Pump) for transferring the liquefied gas can be installed outside the storage tank rather than the submersible type provided inside the storage tank, maintenance is easy.

In addition, there is no need to additionally install a device for supporting a platform for pipe and pump maintenance on the upper part of the storage tank, thereby reducing costs, and the difference in expansion between steel and insulation Insulation cracking can be prevented.

In addition, the present invention can apply a secondary barrier that can protect the hull structure from the risk of LNG leakage when connecting the lower pipe of the storage tank, thereby reducing the risk of cryogenic damage and explosion due to leakage of liquefied gas. This can be prevented and the safety is improved.

The present invention encompasses all embodiments generated by a combination of at least two or more of the above embodiments, or a combination of at least one or more of the above embodiments with known techniques, in addition to the embodiments described above.

Although the present invention has been described in detail through specific examples, it is intended to describe the present invention in detail, and the present invention is not limited thereto, and by those of ordinary skill in the art within the technical spirit of the present invention It will be clear that the transformation or improvement is possible.

All simple modifications or changes of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be made clear by the appended claims.

10: storage tank 20: valve part
30: drip tray 40: pump
50: liquefied gas drain line 60: hull water film part
70: accommodating part 80: purging part
90: reliquefaction device
L1: Liquefied gas supply line L2: Liquefied gas discharge line

Claims (5)

a storage tank provided in the hull in which liquefied gas is stored; and
and a liquefied gas transport line connected to the storage tank to supply liquefied gas to the storage tank or to discharge liquefied gas from the storage tank,
The storage tank is a pressure vessel for storing liquefied gas at high pressure,
The liquefied gas transport line is
But passing through the lower portion of the storage tank, the liquefied gas storage tank, characterized in that the bent portion formed in a loop shape is disposed above the inside of the storage tank. The method of claim 1,
The liquefied gas transport line is
A liquefied gas storage tank, characterized in that the bent portion is partially exposed from the liquefied gas stored in the storage tank provided in an inverted 'U' shape. The method of claim 1,
The liquefied gas transport line is
and a liquefied gas supply line for supplying liquefied gas to the storage tank,
The liquefied gas supply line is
A liquefied gas storage tank, characterized in that it is branched into at least two or more different lengths, respectively, for supplying liquefied gas from above and/or below the inside of the storage tank. 3. The method of claim 2,
The liquefied gas transport line is
and a liquefied gas discharge line for discharging the liquefied gas in the storage tank,
Liquefied gas storage tank comprising a pump connected to the liquefied gas discharge line to transfer the liquefied gas in the storage tank to the liquefied gas discharge line. A ship, characterized in that it has the liquefied gas storage tank according to any one of claims 1 to 4.

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