KR20150145072A

KR20150145072A - Tank structure for decreasing sloshing

Info

Publication number: KR20150145072A
Application number: KR1020140074389A
Authority: KR
Inventors: 김을년
Original assignee: 현대중공업 주식회사
Priority date: 2014-06-18
Filing date: 2014-06-18
Publication date: 2015-12-29
Also published as: KR101583945B1

Abstract

According to an embodiment of the present invention, a sloshing reduction tank structure comprises: a tank which stores a liquid cargo; a support unit which crosses the tank; and a flow prevention unit which is connected to the support unit and where gas and liquid flows in and out when some of a liquid cargo gets stored in the tank, wherein the gas and the liquid has a smaller specific gravity than the liquid cargo to float on the liquid cargo. According to the present invention, the sloshing reduction tank structure prepares a floating body on a free surface of the liquid cargo, and charges gas having different liquefaction temperature and specific density inside the floating body to float in the liquid cargo within the tank and reduces a sloshing phenomenon in the tank.

Description

[0001] Tank structure for decreasing sloshing [

The present invention relates to a sloshing reduction tank structure.

Liquefied natural gas (Liquefied natural gas), Liquefied petroleum gas (Liquefied petroleum gas) and other liquefied gas are widely used in place of gasoline or diesel in recent technology development.

Liquefied natural gas is a liquefied natural gas obtained by refining natural gas collected from a gas field. It is a colorless and transparent liquid with almost no pollutants and high calorific value. It is an excellent fuel. On the other hand, liquefied petroleum gas is a liquid fuel made by compressing gas containing propane (C3H8) and butane (C4H10), which come from oil in oil field, at room temperature. Liquefied petroleum gas, like liquefied natural gas, is colorless and odorless and is widely used as fuel for household, business, industrial, and automotive use.

Such liquefied gas is stored in a liquefied gas storage tank installed on the ground or stored in a liquefied gas storage tank provided in a ship which is a means of transporting the ocean. The liquefied natural gas is liquefied to a volume of 1/600 The liquefaction of liquefied petroleum gas has the advantage of reducing the volume of propane to 1/260 and the content of butane to 1/230, resulting in high storage efficiency.

Here, various types of vessels are being manufactured to transport liquid cargoes to sea. For example, in order to transport liquid cargoes such as liquefied natural gas (LNG), liquefied petroleum gas (LPG), and crude oil, hulls are manufactured according to the characteristics of each cargo. Specific types of liquid cargo storage tanks have been applied to ensure that they are sealed and kept warm.

One of the main load conditions in the production of such hull and liquid cargo storage tanks is the sloshing problem. Sloshing is a phenomenon in which a liquid cargo continuously receives kinetic energy due to movement of the hull, Refers to the behavior of a fluid which causes a strong impact on the inner wall of a storage space (i.e., a liquid cargo storage tank) while rapidly shaking, and such sloshing is considered from the beginning of the production of the hull and the liquid cargo storage tank.

As such, the shape of the hull and the liquid cargo storage tank has been designed to minimize the sloshing caused by the liquid cargo and at the same time to withstand the expected sloshing load. In order to avoid the sloshing load, Shipowners had to accept conditional service conditions with limited cargo load. Nonetheless, due to the uncertainty of the sloshing load, various problems with the damage of unexpected liquid cargo storage tanks need to be constantly generated and improved.

(Prior Art 1) Published Japanese Patent Application No. 10-2013-0043958 (Feb.

It is an object of the present invention to provide a sloshing reduction tank structure capable of reducing damage to a structure of a tank by sloshing caused by liquid cargo.

According to an aspect of the present invention, there is provided a sloshing reduction tank structure including: a tank in which liquid cargo is stored; A support across the tank; And a flow prevention part connected to the support part and having a specific gravity lower than that of the liquid cargo so as to float on the liquid cargo when the liquid cargo is partially stored in the tank.

Specifically, the supporting portion may be vertically disposed in the tank, and may further include a fixing portion that is moved along the length of the supporting portion to fix the position of the flow preventing portion.

Specifically, the apparatus may further include a position adjusting unit for lowering a floating height of the flow preventing unit by allowing a gas or liquid having a specific gravity larger than that of the liquid liquid to flow in and out.

Specifically, the gas or the liquid flowing into the position adjusting section is converted into a solid state by the liquid cargo, so that the rigidity is increased.

Specifically, the apparatus may further include a state change unit provided in the support unit and configured to transfer heat to the material that has been introduced into the position adjustment unit and converted into a solid state.

Specifically, the state transducer is provided to extend across one side of the position adjusting unit across the support unit, thereby conducting heat.

Specifically, the state conversion unit is formed of a hot line.

Specifically, the position adjusting section is characterized in that a wrinkle is formed inside.

Specifically, the flow prevention portion has a larger cross-sectional area than the position adjustment portion, and the flow prevention portion has a step on an outer circumferential surface so that the position adjustment portion is disposed at a step provided in the flow prevention portion, And an outer circumferential surface and a lower side.

Specifically, the position adjusting section is characterized in that a step is formed such that the central portion is made high.

Specifically, the support portion includes a tension bar; A first gas line for supplying a gas or a liquid to the position adjusting unit across the tension bar; And a second gas line for supplying gas or liquid to the flow preventing portion across the tension bar.

Specifically, the present invention is further characterized in that the line member is provided in the flow prevention portion and elastically supports the flow prevention portion to extend in accordance with the volume of the flow prevention portion.

Specifically, the flow preventing portion is spaced from the inner wall surface of the tank so as to prevent the tank from colliding with the tank.

The sloshing abatement tank structure according to the present invention is a sloshing abatement tank structure in which a flocculant is provided on the free surface of a liquid cargo so as to fill a liquid having a specific gravity and a liquefaction temperature different from that of the liquid cargo, The phenomenon can be reduced.

In addition, the present invention can prevent the sloshing of the liquid cargo while floating on the liquid cargo in the tank by using the gas solidified by the liquid cargo and the gas remaining in the gaseous state, have.

1 is a front view showing the inside of a sloshing reduction tank structure according to an embodiment of the present invention.
2 is a plan view showing the inside of the sloshing abatement tank structure according to one embodiment of the present invention.
FIG. 3 is a partial internal view of a sloshing reduction tank structure according to an embodiment of the present invention. Referring to FIG.
4 is a front view showing a state in which the flow prevention portion is folded when the liquid cargo in the sloshing reduction tank structure according to the embodiment of the present invention is emptied or filled.

BRIEF DESCRIPTION OF THE DRAWINGS The objects, particular advantages and novel features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. It should be noted that, in the present specification, the reference numerals are added to the constituent elements of the drawings, and the same constituent elements are assigned the same number as much as possible even if they are displayed on different drawings. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a front view showing the inside of a sloshing reduction tank structure according to an embodiment of the present invention. FIG. 2 is a plan view showing the inside of a sloshing reduction tank structure according to an embodiment of the present invention, FIG. 3 is a partial internal view of the sloshing abatement tank structure according to an embodiment of the present invention. FIG. 4 is a cross-sectional view of a sloshing abatement tank structure according to an embodiment of the present invention. The flow prevention portion is a folded state.

1 to 4, a sloshing abatement tank structure 100 according to an embodiment of the present invention includes a tank 110, a support 120, a flow prevention part 130, a position adjustment part 140, A fixing unit 150, a state conversion unit 160, and a string member 170. [

The tank 110 may be a cargo window of a liquid cargo carrier (LNG carrier, LPG carrier, etc.), and the low temperature liquid cargo loaded in the cargo may experience sloshing due to movement of the ship, There is a risk of breakage, so that this embodiment will be prevented by the following configuration.

In other words, when transporting the liquid cargo stored in the tank 110, the liquid cargo flows in the tank 110 due to movement (movement of the ship, etc.) and applies a large pressure to a certain portion of the tank 110 Singing pressure). This embodiment allows the sloshing phenomenon to be reduced because the sloshing pressure can cause structural damage.

Here, the tank 110 stores liquid contents. The liquid cargo may be a liquefied gas such as Liquefied Natural Gas, Liquefied Petroleum Gas and the like. The liquid cargo stored in the tank 110 may be simply stored or supplied to a customer (not shown) such as an engine. The tank 110 is required to store the liquefied gas in a liquid state, and the tank 110 may have a pressure tank shape which forms an adiabatic structure.

Here, when the liquid cargo to be filled in the tank 110 is natural gas, the liquefaction temperature of methane, which is a main component of natural gas, is -163 ° C and the specific gravity is designed to be 0.5 ton / m 3. Hereinafter, natural gas in which liquid cargo is made of methane will be described as an example.

The support part 120 may support the flow prevention part 130, the position adjustment part 140, the fixing part 150, and the state conversion part 160 across the tank 110. [ Here, the support 120 may include a tension bar 121, a first gas line 122, and a second gas line 123.

The tension bar 121 is a support bar that vertically crosses the center of the tank 110. A thread is formed on the outer circumferential surface of the tension bar 121 so that the fixing part 150 described below can move up and down along the thread. The tension bar 121 not only guides the movement of the fixing part 150 but also allows the position of the flow preventing part 130, the position adjusting part 140 and the state converting part 160 to be disposed in the center of the tank 110 Can support. For example, the tension bar 121 is provided across the center of the tank 110, and the flow restricting portion 130, the position adjusting portion 140, and the fixing portion 150 are provided on the tension bar 121 from the lower portion to the upper portion And a state conversion unit 160 may be provided inside the tension bar 121. [

The first gas line 122 is a line for supplying a gas (or a liquid, hereinafter, a gas will be described as an example for the sake of convenience), and can supply gas to the position adjuster 140 across the tension bar 121 . For example, the first gas line 122 may supply or discharge gas to and from the position adjusting unit 140 in communication with the position adjusting unit 140 across the inside of the tension bar 121. Here, the gas flowing in and out of the first gas line 122 may be a heavy and liquefied gas as compared with the gas flowing in and out of the second gas line 123 such as CO 2. The gas to flow in and out of the position adjusting unit 140 will be described later.

The second gas line 123 is a line for supplying a gas (or a liquid, which will be described below as an example for the sake of convenience) similar to the first gas line 122, The gas can be supplied to the prevention part 130. For example, the second gas line 123 communicates with the flow preventing portion 130 across the inside of the tension bar 121 so as to be separated from the first gas line 122, Supply or discharge. Here, the gas flowing in and out of the second gas line 123 may be a gas that is lighter than the gas flowing in and out of the first gas line 122 such as He, Ar, Ne, N, and is lower in temperature than the liquefying temperature of the liquefied gas. The gas flowing in and out of the flow preventing portion 130 will be described later.

In addition, a valve (not shown) may be provided in each of the first gas line 122 and the second gas line 123 so that gas supply may be controlled. Hereinafter, a gas flowing in and flowing out of the first gas line 122 will be referred to as a first gas, and a gas flowing in and out of the second gas line 123 will be described as a second gas.

The flow prevention part 130 may be formed by weaving a fabric of a composite material capable of withstanding the cryogenic temperature of the liquid material, and may be expanded or reduced in volume depending on whether the gas is supplied or not. Argon Ar: liquefaction temperature -189 deg. C, specific gravity 0.178 ton / m3, helium He: liquefaction temperature -272 [deg.], Which is lighter than methane which is liquid cargo, Lt; 0 > C, specific gravity 0.179 ton / m < 3 >, Neon Ne: liquefaction temperature -249 DEG C, specific gravity 0.090 ton /

Here, the second gas flowing into the flow prevention part 130 has a specific gravity smaller than that of the liquid cargo, a specific gravity smaller than that of the first gas, and a liquefaction temperature lower than that of the liquid cargo. Accordingly, when the second flow restrictor 130 is filled with the second flow restrictor 130, the flow inhibiting portion 130 floats on the liquid phase, and the second gas floated on the flow prevention portion 130 is in a gas state .

The flow preventing portion 130 may be disposed at an interval (for example, 50 cm) between the inner wall surface of the tank 110 and the tank 110 so as to prevent the tank 110 from colliding with the tank 110. The prevention of sloshing of the liquid cargo by the flow preventing portion 130 will be described later. In addition, the state in which the gas is injected into the flow preventing portion 130 to expand the liquid prevents the sloshing phenomenon due to the provision of a part of liquid cargo in the tank 110.

The position adjustment unit 140 lowers the floating height of the flow prevention unit 130. [ That is, the position adjustment unit 140 presses the upper portion of the flow prevention unit 130 with the load of the position adjustment unit 140 to prevent the flow prevention unit 130 from simply drifting on the liquid phase Preventing the movement preventing portion 130, the position adjusting portion 140, and the state converting portion 160, which will be described later, from moving.

In addition, the position adjusting unit 140 can be stepped so that the central portion of the position adjusting unit 140 can be made high without needing to be thick. At this time, the center of the position adjusting unit 140 is formed to have a predetermined thickness, so that it is prevented from being damaged. In this case, the position adjusting unit 140 is fixed at the center of the position adjusting unit 140, .

In addition, the position adjuster 140 may have a wrinkle 141 as shown in Fig. The position adjusting unit 140 may be made of a flexible material such as a fabric (composite material capable of withstanding cryogenic temperatures of liquid cargo), and the position adjusting unit 140 may be made of a material that is heavier than methane, (Solid carbon dioxide: solidification temperature -78.5 ° C (dry ice), specific gravity 1.53 ton / m3), ethanol: solidification temperature -78.5 ° C (dry ice), specific gravity 0.789 ton / m3).

The first gas flowing into the position adjusting unit 140 has a specific gravity larger than that of the second gas and the liquefaction temperature is higher than the temperature of the liquid cargo so that the first gas is supplied to the position adjusting unit 140 in the tank 110, When the gas is charged, the position adjusting unit 140 applies a load to the flow preventing unit 130, and the first gas charged in the position adjusting unit 140 can be in a solid state.

For example, when the tank 110 is at a temperature of -163 DEG C by liquidified liquid methane, and the inside of the tank 110 is partially loaded with the liquefied material not filled, The inert gas such as helium gas can be injected into the flow prevention portion 130 through the gas diffusion layer 123 and the CO2 gas is injected into the position adjustment portion 140. Since the temperature inside the tank 110 is -163 ° C, In the gaseous state, CO2 gas becomes solid state with dry ice, and rigidity can be increased. At this time, the position adjustment unit 140 behaves as a floating body in the tank 110 by the flow prevention unit 130.

In addition, the flow prevention part 130 has a wider cross-sectional area than the position adjustment part 140 and has a step on the outer circumferential surface so that the position adjustment part 140 is disposed at a step provided in the flow prevention part 130, Can be formed to cover the outer peripheral surface and the lower side of the position adjusting portion. Accordingly, when the flow prevention unit 130 and the position adjustment unit 140 are moved by the liquid cargo flowing in the tank 110, the solidified dry ice charged in the position adjustment unit 140 is discharged to the outside of the tank 110 It is possible to prevent the flow preventing portion 130 from colliding with the inner circumferential surface and to prevent the tank 110 from being damaged.

That is, the flow prevention part 130 functions as a cushion function between the position adjustment part 140 and the tank 110 to prevent damage due to collision due to solid state CO2, 110 may be spaced apart from each other by a predetermined distance (50 cm). In this embodiment, the horizontal cross-sectional area of the flow preventing portion 130 is smaller than the horizontal cross-sectional area of the tank 110. Alternatively, the horizontal cross-sectional area of the flow preventing portion 130 and the tank 110 may be the same.

In this embodiment, the amount of the gas to be filled in the flow prevention part 130 and the position adjustment part 140 may be adjusted to design positive buoyancy as shown in FIG. The flow prevention part 130 and the position adjustment part 140 press the liquid cargo to reduce the sloshing phenomenon inside the tank 110. The flow prevention part 130 and the position adjustment part 140 can be moved in the vertical direction according to the amount of the liquid cargo in the tank 110. However, since the flow prevention part 130 and the position adjustment part 140 move in the vertical direction Can be prevented by the fixing portion 150. [

The fixing portion 150 is moved along the length of the supporting portion 120 so as to fix the position of the flow preventing portion 130 and the position adjusting portion 140. [ The fixing part 150 prevents the movement preventing part 130 and the position adjusting part 140 from moving up and down, thereby reducing the sloshing phenomenon of the liquid cargo. The fixing portion 150 may be in the form of a bolt in which a thread is formed on the inner peripheral surface.

The state change unit 160 is provided in the support unit 120 to remove the solidified dry ice when the liquid in the tank 110 is emptied or the liquid is filled. (140).

For example, the state change unit 160 may be formed of a heat line that crosses the inner side of the tension bar 121, which is the support unit 120, and is disposed to abut the position adjustment unit 140. For example, the state change unit 160 is provided to extend between the flow prevention unit 130 and the position adjustment unit 140, and the state change unit 160, which is in the form of a hot wire, So that the area in contact with the position adjusting unit 140 can be widened and the solid state CO2 can be quickly sublimated.

The state converting unit 160 may be connected to a separate heating device (not shown) to generate heat to transfer heat. The state converting unit 160 is provided to abut the position adjusting unit 140 between the flow preventing unit 130 and the position adjusting unit 140 to sublimate the solid state dry ice filled in the position adjusting unit 140, Line 122 to the outside of the tank 110. Accordingly, when the liquid in the tank 110 is empty or the liquid cargo is full, the volume of the flow prevention part 130 and the position adjustment part 140 can be reduced.

The line member 170 is provided in the flow preventing portion 130 to arrange the flow preventing portion 130 whose volume is reduced when the tank 110 is filled with liquid or filled with liquid. The strand member 170 elastically supports the flow preventing portion 130 and can be stretched according to the volume of the flow preventing portion 130. The string member 170 may be formed of a wire or an elastic member.

For example, the string member 170 may be formed in the form of a wire covering an outer side surface or an inner side surface of the flow preventing portion 130, and may be provided at one end or both ends thereof fixed to the flow preventing portion 130. Alternatively, the string member 170 may be a spring, which is an elastic member fixed to both inner ends of the flow preventing portion 130.

Such a string member 170 is extended in its length when the gas is filled in the flow preventing portion 130 to expand the length thereof to support the flow preventing portion 130 and the gas is discharged into the flow preventing portion 130, The length of the flow restricting portion 130 can be restored and both ends of the flow preventing portion 130 can be pulled toward the tension bar 121 side.

As described above, according to the present embodiment, by providing the floating prevention part 130 and the position adjustment part 140 in the form of float on the free surface of the liquid material and using the state change (solidification, sublimation) according to the specific gravity and temperature of the gas, It is possible to reduce the sloshing phenomenon in the fuel cell stack 110.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the same is by way of illustration and example only and is not to be construed as limiting the present invention. It is obvious that the modification and the modification are possible.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

100: Sloshing Reduction Tank Structure 110: Tank
120: support part 121: tension bar
122: first gas line 123: second gas line
130: flow preventing portion 140: position adjusting portion
150: Fixing unit 160:
170:

Claims

A tank in which liquid cargo is stored;
A support across the tank; And
And a flow preventing part connected to the support part and having a specific gravity lower than that of the liquid cargo so as to float on the liquid cargo when the liquid cargo is partially stored in the tank, .

The method according to claim 1,
The support portion is vertically disposed in the tank,
Further comprising a fixing portion that moves along the length of the support portion to fix the position of the flow prevention portion.

The method according to claim 1,
Further comprising a position adjuster for lowering a floating height of the flow preventing portion by a gas or liquid having a specific gravity larger than that of the liquid cargo.

The method of claim 3,
Wherein the gas or the liquid flowing into the position adjusting unit is converted into a solid state by the liquid cargo, so that the rigidity of the sloshing reduction tank structure is increased.

5. The method of claim 4,
Further comprising a state change unit provided in the support unit and configured to transfer heat to the material that has been introduced into the position adjustment unit and converted into a solid state change material.

6. The apparatus according to claim 5,
Wherein the sloshing reduction tank structure crosses the support portion and extends to one side of the position adjustment portion to conduct heat.

6. The apparatus according to claim 5,
Wherein the sloshing reduction tank structure is made of a hot wire.

5. The method of claim 4,
The position adjustment unit,
And a wrinkle is formed on the inner side of the sloshing tank.

5. The method of claim 4,
Wherein the flow prevention portion has a wider cross-sectional area than the position adjustment portion, the flow prevention portion has a step on an outer circumferential surface, the position adjustment portion is disposed on a step provided in the flow prevention portion, And the lower side of the sloshing reduction tank structure.

5. The apparatus according to claim 4,
Wherein the sloshing reduction tank structure has a stepped portion so as to have a high center portion.

The apparatus according to claim 1,
Tension bar;
A first gas line for supplying a gas or a liquid to the position adjusting unit across the tension bar; And
And a second gas line for supplying gas or liquid to the flow preventing portion across the tension bar.

The method according to claim 1,
The sloshing abatement tank structure according to claim 1, further comprising a string member provided in the flow prevention portion and elastically supporting the flow prevention portion and extending according to a volume of the flow prevention portion.

2. The apparatus according to claim 1, wherein the flow-
Wherein a gap is provided between the inner wall surface of the tank and the inner wall surface of the tank so as to prevent the tank from colliding with the tank.