KR20220027692A - 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. According to the present invention, the liquefied gas storage tank comprises: a tank wall forming a storage space for accommodating liquefied gas; an insulating wall provided inside the tank wall; and a barrier provided inside the insulating wall. Between the tank wall and the barrier, an insulating space in which the insulating wall is disposed is sealed and formed. The tank wall is provided with an opening for discharging the bilge generated in the insulating space to the outside on a lower surface, and further comprises a drain box whose upper surface covers the opening to collect the bilge discharged from the opening.

Description

Liquefied gas storage tank and ship including the 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.

According to recent technology development, liquefied gas such as liquefied natural gas (LNG) and liquefied petroleum gas (LPG) is widely used to replace gasoline or diesel.

LNG in ships that transport or store liquefied gas such as LNG at sea, LNG RV (Regasification Vessel), LNG FPSO (Floating, Production, Storage and Offloading), and LNG FSRU (Floating Storage and Regasification Unit) A liquefied gas storage tank (referred to as a "cargo hold") is installed for storing the liquefied gas in a cryogenic liquid state.

In the liquefied gas storage tank, boil off gas (BOG) can be generated by heat intrusion from the outside, and the natural vaporization rate (BOR), which is the vaporization rate of the boil-off gas, is lowered through an adiabatic design. This is the core technology of the design of the liquefied gas storage tank.

Accordingly, such a liquefied gas storage tank may have at least two layers of insulation space, and an Interbarrier Space (IBS) and an Insulation Space (IS) are provided in an outward direction based on the space in which the LNG is stored.

However, as bilge such as water or other contaminants is generated and remains inside the insulating space, there is a risk of lowering the insulation/sealing performance. Therefore, suitable bilge treatment facilities are required for efficient management of the insulated space.

The present invention was created to solve the problems of the prior art as described above, and an object of the present invention is a liquefied gas storage tank that enables rapid and effective treatment of bilge by configuring a drain box that is projected directly to an opening through which bilge is discharged. and to provide a ship including the same.

A liquefied gas storage tank according to an aspect of the present invention includes: a tank wall forming a storage space for accommodating liquefied gas; an insulating wall provided inside the tank wall; and a barrier provided inside the heat insulating wall, between the tank wall and the barrier, a heat insulating space in which the heat insulating wall is disposed is sealed, and the tank wall is a bilge generated in the heat insulating space on a lower surface. It is characterized in that it further comprises a drain box provided with an opening for discharging the to the outside, the upper surface to cover the opening to collect the bilge discharged from the opening.

Specifically, an upper surface of the drain box may be provided integrally with a lower surface of the tank wall in which the opening is formed.

Specifically, the drain box may include a first portion projected onto the heat-insulating space in an up-down direction and a second portion displaced from the heat-insulating space.

Specifically, it may further include a drain line for discharging the bilge collected in the drain box to the outside.

Specifically, a non-explosive gas line for supplying a non-explosive gas to the insulating space through the drain box may be further included, wherein the non-explosive gas line and the drain line may be provided in the second part.

A ship according to an aspect of the present invention has the liquefied gas storage tank, and the tank wall is a hull wall.

The liquefied gas storage tank according to the present invention and a ship including the same, by allowing the upper surface of the drain box to directly face the opening formed at the lower side of the insulating space, can quickly discharge the bilge in the insulating space and prevent the backflow of the bilge. can be effectively prevented.

1 is a cross-sectional view of a ship including a liquefied gas storage tank according to an 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 taken in conjunction with the accompanying drawings and preferred embodiments. 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 subject matter 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, below, the liquefied gas may be LPG, LNG, ethane, or the like, and may mean liquefied natural gas (LNG) by way of example.

1 is a cross-sectional view of a ship including a liquefied gas storage tank according to an embodiment of the present invention.

Referring to FIG. 1 , the present invention may include a vessel 10 provided with a liquefied gas storage tank 20 , wherein the vessel 10 is a liquefied gas carrier or liquefied gas as a propulsion fuel/power generation fuel. It may be a ship 10 to be used.

For example, the ship 10 may be interpreted as a concept including all gas carriers, merchant ships carrying cargo or people other than gas, FSRUs, FPSOs, bunkering vessels, offshore plants, and the like.

The ship 10 includes a hull, and the hull has a hull wall 11 (inner wall). At this time, the storage space of the liquefied gas storage tank 20 may be formed by stacking the insulating walls 21 and 23 and barriers 22 and 24 to be described later on the hull wall 11, which is an independent tank prescribed by IMO. and other generically membrane-type tanks.

The hull wall 11 forms a closed space through the upper surface (upper deck), the lower surface (bottom surface, tank top, etc.), the left and right sides, etc. ) are sequentially stacked and the liquefied gas storage tank 20 may be formed.

As will be described in detail below, as the barriers 22 and 24 are provided on the inside of the insulating walls 21 and 23, the insulating walls 21 and 23 are accommodated between the barriers 22 and 24 and the hull wall 11. A closed insulated space is formed. In this case, bilge may exist in the insulating space, and the hull wall 11 may be provided with an opening 111 on the lower surface to discharge the bilge to the outside.

The bilge generated in the heat insulation space may be discharged through the opening 111 formed in the hull wall 11 after being collected to the lower surface of the hull wall 11 . That is, the discharge of bilge can be made naturally by using gravity, and active discharge of bilge such as pumping and suction can be restricted in order to prevent damage to the insulating walls 21 and 23 .

The drain box 31 of the drain unit 30 may communicate with the opening 111 , and the drain unit 30 will be described in detail below.

The present invention will be described as an example that the liquefied gas storage tank 20 is formed by stacking the insulating walls 21 and 23 and the barriers 22 and 24 on the hull wall 11, and in addition, the present invention provides the hull wall ( 11), rather than the hull wall 11 and the insulating walls (21, 23) and the barriers (22, 24) are laminated on the independent tank wall to form the liquefied gas storage tank (20) also encompasses.

In the latter case, the liquefied gas storage tank 20 may be provided independently, and may be mounted in various locations such as inside or outside the hull. That is, the liquefied gas storage tank 20 of the present invention can be either a stand-alone type or a membrane type depending on the deformation, and in the case of the stand-alone type, IMO Type A, B, C, etc. can all be covered.

Hereinafter, with reference to FIG. 1, the liquefied gas storage tank 20 and the drain unit 30 included in an embodiment of the present invention will be described.

The liquefied gas storage tank 20 is a heat insulating wall 21 that is laminated on the hull wall 11 (which may be a tank wall, hereinafter, the case of the hull wall 11 will be described for convenience) forming a storage space for accommodating the liquefied gas. , 23) and barriers 22 and 24.

The insulating walls 21 and 23 are provided on the inside of the hull wall 11 and maintain a low-temperature storage state of the liquefied gas. The liquefied gas storage tank 20 forcibly liquefies the gas existing in the gas phase at room temperature and stores it in a liquid phase, and it is necessary to prevent evaporation by maintaining the liquefied gas at a low temperature. Accordingly, the liquefied gas storage tank 20 is provided with at least one layer of insulating walls 21 and 23 to surround the storage space.

The heat insulating walls 21 and 23 may be provided with various heat insulating materials 211 and 231 having heat insulating performance. For example, the heat insulating materials 211 and 231 are provided as a polyurethane block or a polyurethane spray layer, or heat insulating materials such as pearlite. It may be provided as an insulation box filled with a material.

The heat insulating walls 21 and 23 may include a secondary heat insulating wall 21 provided inside the hull wall 11 , and the secondary heat insulating wall 21 includes a heat insulating material 211 and a hull wall 11 . ) may include a plywood 212 for fixing. The plywood 212 may be provided on the outside to be fixed to the hull wall 11 and the heat insulating material 211 may be provided on the inside of the plywood 212 .

The plywood 212 may be fixed to the hull wall 11 through an adhesive material such as mastic 213, and of course, a fixing structure such as stud bolts (not shown) may be additionally used.

A plurality of secondary heat insulating walls 21 are installed on the hull wall 11 , and a separate insulating material (not shown) may be filled in a gap between each of the secondary insulating walls 21 . The insulating material between the secondary insulating walls 21 may be made of the same or different material (eg, glass wool) as the insulating material 211 of the secondary insulating wall 21 .

A secondary barrier 22 may be provided inside the secondary heat insulating wall 21 , and a primary heat insulating wall 23 may be provided inside the secondary barrier 22 . The primary insulating wall 23 includes an insulating material 231 and a plywood 232 similarly to the secondary insulating wall 21, but only the insulating material 231 and the plywood 232 in the primary insulating wall 23 ) the stacking order may be opposite to the order in the secondary thermal insulation wall 21 .

The primary insulating wall 23 may have an outer surface of the insulating material 231 fixed to the secondary barrier 22 through an adhesive material, and the primary barrier ( 24) may be provided with a fixing part (not shown) made of metal or the like.

Among the primary insulating walls 23, especially in the case of the primary insulating wall 23 provided at the corner, a plywood 212 may be provided on the outside facing the secondary barrier 22 for structural strength reinforcement, etc. there is.

In this case, the primary insulating wall 23 of the corner may be provided with a plurality of layers of plywood 212, unlike the primary insulating wall 23 provided in a portion other than the corner, and furthermore, the primary insulating wall 23 of the corner ) It is also possible that the insulating material 231 is omitted and made only of the plywood 232 .

Corner barriers 241 in a bent form according to the angle of the corners may be provided on the primary insulating walls 23 of the corners, and primary barriers 24 are installed on both sides of the corner barriers 241 to provide primary insulation The inside of the wall 23 may be sealed.

A barrier 221 on the side of the insulating wall is provided on the inner surface of the secondary insulating wall 21 described above as the secondary barrier 22, so that the barrier 221 on the side of the insulating wall is also cut off due to the gap between the secondary insulating walls 21 is provided. In this case, the pair of insulating wall-side barriers 221 are sealed by the connection barrier 222 , and the primary insulating wall 23 may also be provided with a predetermined gap to seal the connection barrier 222 .

A connection insulating wall (not shown) in which the insulating material 231 and the plywood 232 are laminated may be provided in the gap between the pair of primary insulating walls 23, and the connection insulating wall is also substantially the primary It may be of a configuration included in the insulating wall (23).

The barriers 22 and 24 are provided inside the heat insulating walls 21 and 23 and seal the storage space. The insulating walls 21 and 23 have a function of insulation, but cannot implement airtightness. By providing the barriers 22 and 24, the liquefied gas storage tank 20 prevents leakage of liquefied gas/evaporated gas stored in the storage space. can do.

The barriers 22 and 24 may be made of various materials capable of implementing airtightness, and may be a composite sheet in which a metal sheet (SUS, etc.) and a non-metal sheet (glass fiber, etc.) are combined, or a metal sheet alone, a non-metal sheet alone, etc. , the present invention does not limit the material or structure of the barriers 22 and 24.

and a secondary barrier 22 laminated on the inner side of the secondary heat insulating wall 21 . The secondary barrier 22 may include a thermal insulation wall-side barrier 221 provided on an inner surface of the secondary thermal insulation wall 21 and a connection barrier 222 interconnecting the thermal insulation wall-side barrier 221 .

The insulating wall-side barrier 221 may be spaced apart from each other as the plurality of secondary insulating walls 21 are disposed with a gap as described above. 221) by adhesive or the like to seal between the barriers 221 on the insulating wall side.

As such, the secondary barrier 22 implements sealing on the inside of the secondary thermal insulation wall 21, and a closed thermal insulation space is formed between the hull wall 11 and the secondary barrier 22, and the thermal insulation space The secondary heat insulating wall 21 is accommodated therein. The insulating space between the hull wall 11 and the secondary barrier 22 may be referred to as an insulation space (IS).

At this time, since water may be generated in the insulating space or foreign substances generated during construction or testing may remain, a drain unit 30 to be described later may be utilized to discharge foreign substances (bilge) in the insulating space to the outside.

In addition, the barriers 22 and 24 include a primary barrier 24 , and the primary barrier 24 is provided on the inner surface of the primary heat insulating wall 23 . The primary barrier 24 is made of a material such as metal in order to prepare for contraction/expansion due to the liquefied gas contained in the storage space and has a structure having wrinkles, and the shape of the wrinkles is not particularly limited.

In the case of a corner, the primary barrier 24 may be interconnected with the corner barrier 241 provided inside the corner primary insulating wall 23 in the middle to implement sealing. Therefore, the primary barrier 24 forms a closed insulating space between the secondary barrier 22 and the insulating space between the secondary barrier 22 and the primary barrier 24 is IBS (Interbarrier Space). may be referred to as

In this way, the insulating walls 21 and 23 and the barriers 22 and 24 may be provided in a double layer. In addition, in the present invention, the insulating walls 21 and 23 and the barriers 22 and 24 are one-layer or different from the previous description. It is also possible to be provided on three or more floors.

However, for reference, the drain unit 30 to be described later may be used to naturally discharge the bilge in the heat insulation space closest to the hull wall 11 .

The drain unit 30 collects bilge generated in the heat insulating space sealed between the hull wall 11 and the barriers 22 and 24 . The drain unit 30 includes a drain box 31 , a drain line 32 , and a non-explosive gas line 33 .

The drain box 31 covers the opening 111 provided in the hull wall 11 . The drain box 31 may have a box shape including an upper surface, a lower surface, and a peripheral surface, and the upper surface may cover the opening 111 to collect bilge discharged from the opening 111 therein.

At this time, the drain box 31 is provided integrally with the lower surface of the hull wall 11 in which the upper surface is formed with the opening 111. That is, the secondary heat insulating wall 21 is provided on the inner side with respect to the hull wall 11 and the drain box 31 is provided on the outer side.

In this case, the drain box 31 may have a first portion 311 that is projected into the thermal insulation space in the vertical direction. Therefore, when the bilge falls by gravity through the opening 111 provided in the hull wall 11 , the falling bilge may naturally flow into the drain box 31 .

The drain box 31 further includes a second portion 312 that is displaced from the heat insulating space. That is, in the drain box 31 , a first part 311 and a second part 312 are provided integrally, and the first part 311 is disposed directly below the heat insulating walls 21 and 23 , and the second part 312 . ) may be provided so as to be deviated from the front or side of the insulating walls 21 and 23.

In this case, for example, the drain box 31 may be provided below the corner portion of the liquefied gas storage tank 20 . Accordingly, the drain box 31 is provided adjacent to the point where the heat insulating walls 21 and 23 terminate at the corner, and thus may include the first part 311 and the like overlapping the heat insulating walls 21 and 23 vertically. .

Through this, the drain box 31 has an upper surface of the drain box 31 without installing a separate pipe from the opening 111 to the inside of the drain box 31 , and the lower surface of the hull wall 11 in which the opening 111 is formed. By being provided integrally with the bilge can be quickly collected into the drain box (31).

In addition, the drain box 31 may block the bilge collected therein from flowing into the insulating space through the opening 111 . This is because, when the drain box 31 is connected to the opening 111 through a separate pipe, there is a risk of backflow of the bilge depending on the diameter of the pipe.

That is, in the present embodiment, the internal space and the insulating space of the drain box 31 are arranged to face each other with the opening 111 interposed therebetween, thereby enabling efficient collection and processing of bilge.

In addition, in the second part 312 of the drain box 31 , a manhole (not shown) through which an operator can enter the drain box 31 may be provided, and the manhole is a non-explosive gas to be described later. It may be disposed at a position that does not interfere with the line 33 .

A drain line 32 is provided in the drain box 31 . The drain line 32 may discharge the bilge collected in the drain box 31 to the outside, and for this, the drain line 32 may be connected to the lower surface of the drain box 31 .

In this case, the drain box 31 may have a lower surface inclined toward the drain line 32 . That is, the drain box 31 may provide an angle to the lower surface of the drain box 31 so that the bilge collected on the floor can be smoothly transferred to the drain line 32 .

The drain line 32 may be provided in the second portion 312 . That is, the drain line 32 may be provided to be displaced directly below the heat insulating space. Through this, a backflow of gas between the drain line 32 and the opening 111 may be primarily prevented.

In addition, a shielding wall (not shown) may be provided on at least a portion of the periphery of the opening 111 on the upper surface of the drain box 31 to prevent the backflow of gas, and the shielding wall is not preferably transmitted to the insulating space. It may be provided to prevent the inflow of gas into the opening 111 with respect to the non-existent gas.

However, in the injection of the non-explosive gas, which will be described later, by sufficiently injecting the non-explosive gas into the drain box 31 , the non-explosive gas may be introduced into the insulating space beyond the shielding wall.

The drain box 31 is provided with a non-explosive gas line 33 . The non-explosive gas line 33 may supply a non-explosive gas into the insulating space through the drain box 31 , and the non-explosive gas may mean nitrogen, an inert gas, or the like.

As the non-explosive gas is injected into the insulating space, the internal pressure of the insulating space can be adjusted, thereby preventing dangerous leakage of liquefied gas in the case of breakage of the barriers 22 and 24 .

The non-explosive gas line 33 may be provided on the upper surface of the drain box 31 , for example, in the second part 312 . Accordingly, the non-explosive gas injected into the insulating space through the non-explosive gas line 33 may flow along the U-shaped flow while passing through the drain box 31 .

That is, the non-explosive gas line 33 and the drain line 32 may be provided to face up and down, but the drain line 32 extends from the lower surface to the outside (downward) of the drain box 31, while the non-explosive The gas line 33 may extend from the upper surface to the inside (lower side) of the drain box 31 so that an end thereof may be located at a predetermined point inside the drain box 31 .

As described above, in this embodiment, the drain box 31 is provided directly below the opening 111 when collecting bilge generated in the insulating space by gravity, thereby ensuring rapid collection of bilge and preventing backflow of bilge. can be effectively prevented.

It goes without saying that, in addition to the above-described embodiments, the present invention may include a combination of the embodiments and known techniques known to those skilled in the art as additional embodiments.

Although the present invention has been described in detail through specific examples, this is for the purpose of describing the present invention in detail, and the present invention is not limited thereto. 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 protection scope of the present invention will become apparent from the appended claims.

10: Ship 11: Hull wall
111: opening 20: liquefied gas storage tank
21: secondary insulation wall 211: insulation material
212: plywood 213: mastic
22: secondary barrier 221: insulating wall side barrier
222: connection barrier 23: primary insulation wall
231: insulation 232: plywood
24: primary barrier 241: corner barrier
30: drain part 31: drain box
311: first part 312: second part
32: drain line 33: non-explosive gas line

Claims (6)

a tank wall forming a storage space for accommodating liquefied gas;
an insulating wall provided inside the tank wall; and
Including a barrier provided on the inside of the insulating wall,
Between the tank wall and the barrier, an insulating space in which the insulating wall is disposed is sealed and formed,
The tank wall is provided with an opening on the lower surface for discharging the bilge generated in the insulating space to the outside,
Liquefied gas storage tank, characterized in that the upper surface further comprises a drain box to cover the opening to collect the bilge discharged from the opening. According to claim 1, wherein the drain box,
Liquefied gas storage tank, characterized in that the upper surface is provided integrally with the lower surface of the tank wall in which the opening is formed. According to claim 1, wherein the drain box,
A first part projected to the thermal insulation space in the vertical direction;
Liquefied gas storage tank, characterized in that it comprises a second portion that is displaced from the insulating space. 4. The method of claim 3,
Liquefied gas storage tank, characterized in that it further comprises a drain line for discharging the bilge collected in the drain box to the outside. 5. The method of claim 4,
Further comprising a non-explosive gas line for supplying a non-explosive gas to the insulating space through the drain box,
The non-explosive gas line and the drain line are liquefied gas storage tank, characterized in that provided in the second part. With the liquefied gas storage tank of any one of claims 1 to 5,
The tank wall is
A ship characterized in that it is a hull wall.

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