KR20180029165A - Cargo for liquefied gas - Google Patents

Abstract

A liquefied gas holding window is disclosed. According to an aspect of the present invention, there is provided a liquefied gas storage tank, including: a storage tank disposed inside a hull and containing a liquefied gas; An inner space provided between the hull and the storage tank; A powder insulation material filled in the inner space to insulate the storage tank; An expansion member provided in the inner space; And a fluid supply system for supplying or recovering fluid to the expansion member to expand or contract the fluid.

Description

{CARGO FOR LIQUEFIED GAS}

The present invention relates to a liquefied gas hold, and more particularly to a liquefied gas hold that includes a heat insulating structure that effectively insulates low-temperature liquefied gas.

The liquefied gas is a liquid made by cooling or compressing a gas. The liquefied gas is a gas that is phase-changed into liquid by cooling it at room temperature for convenience of transportation and storage. One of the most widely used and important resources in liquefied gas is Liquefied Natural Gas (LNG). Liquefied natural gas refers to a colorless transparent cryogenic liquid that reduces the volume of methane-based natural gas by -162 degrees Celsius to 1/600.

Recently, as liquefied natural gas has been used as an important energy resource, an efficient transportation method has been examined in which liquefied natural gas can be mass-delivered from a production site to various demand sites. As part of this effort, a liquefied gas transport vessel capable of transporting large volumes of liquefied natural gas through the sea has been developed.

Liquefied gas transport vessels are equipped with liquefied gas cargo holds capable of withstanding cryogenic temperatures to store and store liquefied natural gas. Liquefied natural gas has a higher vapor pressure than atmospheric pressure and has a boiling temperature of ultra-low temperature. Therefore, the liquefied gas hold window should be made of a material that can withstand extremely low temperatures. It is also resistant to other thermal stresses and heat shrinkage and has a unique thermal insulation structure .

The storage tanks are classified into independent type and membrane type depending on whether the load of the cargo is directly applied to the insulating structure. Among these, the independent storage tanks have been adopted for various liquefied gas transportation vessels because they can accommodate liquefied natural gas in a relatively simple and stable structure.

In this independent type storage tank, a storage tank is provided in a space inside a cargo hold such as a hull of a floating type floating structure such as a ship, and a heat insulating structure is provided between the outer surface of the storage tank and the inner surface of the hull. As such a heat insulating structure, a heat insulating member made of a plate-like polyurethane foam (PUF) or the like or a powder insulating material made of an independent powder can be used.

Among them, the heat insulation method using powder insulation is advantageous in that the efficiency of installation and operation of the cargo hold can be improved because of quick and easy filling, but due to the change of the size of the storage tank, the powder insulating material presses the storage tank or hull There is a disadvantage that the heat insulating performance can be changed. This is due to the fact that the storage tank varies in size depending on the amount of stored liquefied gas stored therein. Since the liquefied gas is in a cryogenic state, the storage tank expands when the storage tank shrinks and the storage tank expands when the storage tank is full. Therefore, the powder insulation may not be filled in as necessary by the storage tank changing in size, It is to press and damage the hull.

In addition, there is also a problem that the heat insulation performance deteriorates due to the sinking phenomenon over time due to the self weight of the powder insulation.

Patent Document 1) Korean Published Patent Application No. 10-2008-0097519 (published on November 6, 2008)

The present invention seeks to provide a liquefied gas cargo hold including an insulating structure capable of effectively insulating the liquefied gas stored in a storage tank.

An object of the present invention is to provide a liquefied gas holding window capable of quickly and easily installing a heat insulating structure.

The present invention seeks to provide a liquefied gas cargo hold capable of stably carrying out insulation of a liquefied gas loaded by a simple structure.

According to one aspect of the present invention, there is provided a storage tank comprising: a storage tank disposed inside a hull and containing a liquefied gas; A powder insulation material filled in an inner space provided between the hull and the storage tank to insulate the storage tank; An expansion member provided in the inner space; And a fluid supply system for supplying or recovering fluid to or from the expansion member to expand or contract the fluid.

The fluid supply system includes a fluid transfer line; And a fluid reservoir provided in the fluid transfer line and storing the fluid.

The fluid transfer line including a fluid supply line for supplying fluid from the fluid reservoir to the expansion member; And a fluid recovery line that recovers fluid from the expansion member toward the fluid reservoir.

The fluid supply system may include a pump for pressurizing and delivering fluid to the fluid transfer line.

The fluid supply system comprising: a control valve provided on the fluid transfer line; And a controller for controlling the flow rate of the fluid by regulating opening and closing of the fluid reservoir or the pump or the regulating valve.

Wherein the expansion member includes: an upper expansion member positioned at an upper portion of the storage tank; And a lower expansion member located at a lower portion of the storage tank, and the control unit may selectively supply the fluid to the upper expansion member or the lower expansion member.

In the liquefied gas holding window according to the present invention, the efficiency of installation and operation of the cargo hold is improved by using the powder insulating material capable of quick and easy filling.

In addition, by allowing the powder insulator to be pressed and inserted using the expansion member at a position where the powder insulation is difficult to insert, the cargo hold installation work can be performed quickly and easily.

Further, a control unit that controls a fluid supply system that supplies or retrieves fluid to / from the expansion member can be easily adapted to the size change due to thermal deformation of the storage tank. This is because the storage tank shrinks or expands in size depending on the amount of liquefied gas stored therein.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing a liquefied gas holding window according to a first embodiment of the present invention, showing an expansion member in a contracted state.
2 is a cross-sectional view showing a liquefied gas holding window according to a first embodiment of the present invention, showing an expanding member in an expanded state.
Figs. 3 to 5 show a first operation example of the liquefied gas holding window according to the first embodiment of the present invention. Fig. 3 shows a first state, Fig. 4 shows a second state, and Fig.
Figs. 6 to 7 show a second operation example of the liquefied gas holding window according to the first embodiment of the present invention, in which Fig. 6 shows the first state and Fig. 7 shows the second state.
8 is a cross-sectional view showing a liquefied gas holding window according to a second embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided to fully convey the spirit of the present invention to a person having ordinary skill in the art to which the present invention belongs. The present invention is not limited to the embodiments shown herein but may be embodied in other forms. For the sake of clarity, the drawings are not drawn to scale, and the size of the elements may be slightly exaggerated to facilitate understanding.

1 and 2 are sectional views showing a liquefied gas holding window according to a first embodiment of the present invention. Fig. 1 shows an expanding member 110 in a contracted state, and Fig. 2 shows an expanded member 110 in an expanded state.

Referring to the drawings, a liquefied gas holding window according to a first embodiment of the present invention includes a storage tank 20 disposed inside a hull 10 for storing a liquefied gas, a storage tank 20 for storing liquefied gas, And a fluid supply system 100 that supplies or recovers fluid to the expansion member 110 and expands or contracts the fluid to or from the expansion member 110. The fluid supply system 100 includes an inner space 11 provided in the inner space 11, do.

The ship 10 is a marine structure, and may be an LNG carrier, an LNG RV, or a marine plant such as an LNG FPSO or an LNG FSRU that transports or stores a liquid cargo such as LNG. The hull 10 may be constructed of a double hull of an outer hull and an inner hull and a storage tank 20 for storing the liquefied gas is disposed inside the inner plate of the hull 10 .

The storage tank 20 is used to store cryogenic liquefied gas such as Liquefied Natural Gas (LNG), Liquefied Petroleum Gas (LPG), and Dimethyl Ether (DME) . That is, the storage tank 20 may be a carrier for transporting liquefied gas such as an LNG carrier, an LNG RV (Regasification Vessel) carrier, an LPG carrier, or an ethylene carrier, or a carrier for transporting liquid gas such as a floating storage regasification unit (FSRU) Storage Offloading), BMPP (Barge Mounted Power Plant), etc., for storage and production of liquefied gas. Also, the storage tank 20 can be applied not only to marine equipment but also to land equipment for storing liquefied gas.

The liquefied gas stored in the storage tank 20 can be used to mean all of the gaseous fuels generally stored in a liquid state such as LNG or LPG, ethylene, ammonia, and the like. Further, Can also be expressed as liquefied gas for convenience.

The storage tank 20 may be an independent type storage tank and may be dried together with the hull 10 or may be manufactured separately from the hull 10 and mounted inside the hull 10. Further, the storage tank 20 may include a barrier structure (not shown) and a thermal insulation layer (not shown) to receive the liquefied gas. At this time, the barrier structure can be contacted with the stored substance stored in the storage tank 20, and can absorb the sloshing shock due to the flow of the stored substance. In addition, the barrier structure may be made of a low temperature resistant alloy such as aluminum alloy, SUS, and 9% nickel to accommodate cryogenic liquefied gas. A liquid dome (not shown) may be provided on the upper side of the storage tank 20 in which a pipe for supplying liquefied gas to the storage tank 20 or for discharging the liquefied gas from the storage tank 20 is provided .

The inner space (11) is provided between the inner surface of the hull (10) and the storage tank (20). The storage tank 20 is a stand-alone type and is spaced apart from the inner surface of the hull 10 by a predetermined distance. The inner space 11 is provided between the outer surface of the storage tank 20 and the hull 10.

The support means 30 is for holding the storage tank 20 in the hull 10 and includes a tank support 31 that largely supports the load of the storage tank 20, And a rotation restrainer 32 for preventing movement or rotation of the storage tank 20 by the rotation restrainer 32. The support means 30 is interposed between the hull 10 and the storage tank 20 to hold the storage tank 20 in the inner space 11 of the hull 10.

The tank support 31 is disposed under the storage tank 20 and includes a support member (not shown) fixed to the hull bottom 10a, a block member (not shown) for supporting the storage tank 20, And a movement restricting member (not shown) installed in the tank 20 to restrain movement of the block member (not shown). At this time, the block member may be made of a material such as a compressed hard wood block, which can easily block the heat conduction, and can support the lower surface of the storage tank 20.

The rotation restraint 32 may be provided to prevent the storage tank 20 from flowing or rotating in the inner space 11 of the hull 10. The rotation restrainer 32 includes a key member (not shown) provided on the tank body 100 such as a pitching key, a stopper member (not shown) provided on the hull 10, And a buffer member (not shown) interposed between the key member and the stopper member.

The fluid supply system 100 is a means for supplying fluid to the expansion member 110 to be described later and includes a fluid transfer line 101 and a control valve 102, a pump 103, a fluid reservoir 104, And a control unit 120. The fluid may be, for example, air, oil or hydraulic fluid or nitrogen. Among them, nitrogen (N2) is a colorless and odorless gas, and has a very low chemical reactivity. Therefore, it has an effect of reducing the explosion risk of liquefied gas.

The fluid transfer line 101 may be a pipe having a circular cross-section for transferring the fluid. The fluid transfer line 101 may be angled at an acute angle or a right angle to change the direction according to the shape of the hull 10 or the design method. For this purpose, a connection joint such as a T joint may be provided on the fluid transfer line 101 have.

The control valve 102 may be a flow control valve for regulating the amount of fluid flowing in the fluid transfer line 101, that is, the flow rate. The control valve 102 is provided with a total of four control valves 102 on the inlet side of the upper expansion member 111 and a pair of the expansion members 112 provided on the hull 10, ) Can be controlled.

The pump 103 pressurizes the fluid flowing along the fluid transfer line 101 to discharge or recover the fluid. For this purpose, the pump 103 may be, for example, a two-way type air pump. This pump 103 is also connected to the fluid transfer line 101 connected to the respective expansion member 110 so as to separately supply fluid to the respective expansion members 110 unlike the control valve 102, One can be provided. For example, if the expansion member 110 is installed in four parts as shown in the figure, four pumps 103 are also provided.

The fluid reservoir 104 may be connected to the fluid transfer line 101 to supply or recover fluid to the fluid transfer line 101. For example, if air is supplied as a fluid, the fluid reservoir 104 is an air tank for holding compressed air. A safety valve is installed to prevent accident caused by excessive pressure, and an internal pressure is 5 to 7 kgf / cm 2 Lt; / RTI >

The expansion member (110) can expand or contract by the fluid supplied from the fluid transfer line (101). The expansion member 110 includes an upper expansion member 111 installed at a corner where the ceiling surface and the side face meet inside the hull 10 for pressurization of the powder insulator P to be described later, And a lower expansion member 112 installed at a corner where the bottom surface and the side meet.

The control unit 120 measures the temperature of the hull 10 to determine the heat insulating performance of the powder insulator P or measures the pressure applied to the hull 10 and determines whether or not to supply the fluid to the expansion member 110 You can decide. If the filling amount of the powder insulator P is small, the temperature of the hull 10 will be lower than the set value due to insufficient heat insulation performance. Therefore, if the fluid is supplied to the expansion member 110 and the filling amount of the powder insulator P is excessive And accordingly, the pressure applied to the hull 10 is large, so that the fluid supplied to the expansion member 110 is recovered.

As described above, the present invention includes a control unit 120 that controls the fluid supply system 100 that supplies or recovers fluid to or from the expansion member 110, so that it can easily respond to the size change due to thermal deformation of the storage tank 20 . The size of the storage tank 20 is shrunk or expanded according to the amount of the liquefied gas stored therein, and the powder insulator P is required to have a different filling amount accordingly.

3 to 5 show a first operation example of the liquefied gas holding window according to the first embodiment of the present invention. Fig. 3 shows a first state in which the powder insulator P is filled, Fig. 5 shows a third state in which the powder insulator P is densely packed due to the expansion of the expansion member 110. Fig.

The powder insulation material P is filled in the inner space 11 to insulate the liquefied natural gas contained in the storage tank 20. The powder insulation material P may be in the form of an independent powder and may be filled in the inner space 11 by a filling pump (not shown) or the like. Since the powder insulator P is in powder form, it is filled more quickly than a separate heat insulating layer is provided on the storage tank 20, which makes it possible to manufacture and install the liquefied gas holding window easily and quickly . The powder insulator P may be at least one of glass bubble and perlite having excellent heat insulating properties for heat insulation.

Referring to FIG. 3, the powder insulator P includes a hull 10 and a storage tank (not shown) for inspecting the storage tank 20 at the time of ballast voyage or ship drying, 20 in the inner space 11. In this first state, the powder insulator (P) is filled in the inner space (11) without any gap, so that the storage tank (20) is insulated with uniform performance.

However, at the time of laden voyage as in the second state of FIG. 4, the storage tank 20 is filled with cryogenic liquefied gas, so that the storage tank 20 is reduced in volume due to the low temperature. At this time, the internal space 11 is in a state where the powder insulation material P is empty by the reduced volume of the storage tank 20. In addition, since the powder insulator P is submerged in the form of powder over time, this also causes a void space in the internal space 11.

As shown in Fig. 5, the expansion member 110 is filled with the powder insulation material P by supplying fluid from the fluid supply system 100 to expand the void space in the internal space 11 as in the second state of Fig. 4 . The powder insulator P is pushed into the empty space of the inner space 11 and is pushed in.

6 to 7 show a second operation example of the liquefied gas holding window according to the first embodiment of the present invention. Fig. 6 shows a first state in which the expansion member 110 is contracted, Fig. 7 shows a state in which the expansion member 110 And exhibits an expanded second state.

The method of inserting the storage tank 20 using the powder insulator P has a problem that the powder insulator P is difficult to be filled in the lower part of the storage tank 20. [ Because the powder insulator P is generally pressed and inserted through the upper portion of the storage tank 20, the powder insulator P is hardly uniformly filled up to the lower portion of the storage tank 20. [

Referring to the drawings, the lower expansion member 112 is inflated by the fluid supply system 100, thereby solving the above problem. The inflated lower expansion member 112 presses the powder insulator P to the lower side of the storage tank 20 and the pressurized powder insulator P fills the empty space under the storage tank 20. [ At this time, as shown in the drawing, the upper expansion member 111 may not be used. However, if the filling of the powder insulator P is insufficient at the peripheral portion of the rotation restrainer 32, .

The control unit 120 controls the expansion of the lower expansion member 112 by controlling the performance of the pump 103 or the amount of fluid discharged from the fluid reservoir 104 to the fluid transfer line 101 by the control valve 102, Can be adjusted. The regulating valve 102 is provided upstream of the upper expansion member 111 and upstream of the lower expansion member 112 so that the fluid is supplied to the upper expansion member 111 or the lower expansion member 112 Can be selectively supplied.

As described above, in the liquefied gas holding window according to the present invention, the powder insulator P is pressed and inserted using the expansion member 110 at a position where the powder insulator P is difficult to be inserted, can do.

8 is a cross-sectional view showing a liquefied gas holding window according to a second embodiment of the present invention. Referring to this, in the second embodiment, the fluid supply system 200 includes the fluid supply line 201 and the fluid return line 204, rather than one fluid transfer line, to facilitate bidirectional fluid transfer .

At this time, the fluid supply line 201 and the fluid return line 204 are provided with a first control valve 202 and a second control valve 205 for controlling the flow rate, a first pump 203 for pressurizing and sending the fluid, And a second pump 206 may be provided. The control unit 220 can separately adjust the control valves 202 and 205 and the pumps 203 and 206 to easily perform the supply or recovery of the fluid.

The fluid reservoir 207, the expansion member 210 and the control unit 220 perform the same functions as the fluid reservoir 104, the expansion member 110 and the control unit 120 in the first embodiment. .

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, You will understand. Accordingly, the true scope of the invention should be determined only by the appended claims.

P: powder insulation 10: hull
10a: Floor 11: Interior space
20: storage tank 30: support means
31: tank support 32: rotation restrainer
100: fluid supply system 101: fluid transfer line
102: regulating valve 103: pump
104: fluid reservoir 110: expansion member
111: upper expansion member 112: lower expansion member
120: control unit 200: fluid supply system
201: fluid supply line 202: first control valve
203: First pump 204: Fluid recovery line
205: second control valve 206: second pump
207: fluid reservoir 210: expansion member
220:

Claims (6)

A storage tank located inside the hull and containing liquefied gas;
A powder insulation material filled in an inner space provided between the hull and the storage tank to insulate the storage tank;
An expansion member provided in the inner space; And
And a fluid supply system that supplies or recovers fluid to or from the expansion member to expand or contract the fluid. The method according to claim 1,
The fluid supply system
Fluid transfer line; And
And a fluid reservoir provided on the fluid transfer line. 3. The method of claim 2,
The fluid transfer line
A fluid supply line for supplying fluid from the fluid reservoir toward the expansion member; And
And a fluid recovery line for withdrawing fluid from the expansion member toward the fluid reservoir. 3. The method of claim 2,
The fluid supply system
And a pump provided on the fluid transfer line for pressurizing and delivering the fluid. 5. The method of claim 4,
The fluid supply system
An adjustment valve provided on the fluid transfer line; And
And a control unit controlling the operation of at least one of the fluid reservoir, the pump, and the control valve to regulate the flow rate of the fluid flowing through the fluid transfer line. 6. The method of claim 5,
A plurality of expansion members are provided inside the hull,
Wherein the control unit controls the fluid to be selectively supplied to the plurality of expansion members.

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