KR102084995B1 - Cargo for liquefied gas - Google Patents

Abstract

Liquefied gas cargo hold according to the present invention is a primary barrier for preventing the leakage of liquefied gas; A secondary barrier for preliminarily preventing leakage of liquefied gas; An upper insulating wall provided between the primary barrier and the secondary barrier; A lower insulating wall provided between the secondary barrier and the support wall; And a signal generator installed between the secondary barrier and the lower insulating wall and generating a leakage signal in a cryogenic state when liquefied gas leaks.

Description

Liquefied Gas Cargo Hold {CARGO FOR LIQUEFIED GAS}

The present invention relates to a liquefied gas cargo hold provided for storing liquefied gas inside a vessel.

Liquefied gas (Liquefied Gas) is a liquid made by cooling or compressing the gas, the consumption of liquefied gas, such as LNG (Liquefied Natural Gas), LPG (Liquefied Petroleum Gas) or liquefied hydrogen is increasing worldwide.

Today, low temperature liquefaction methods are mainly used to transport large quantities of substances such as natural gas. In particular, in order to transport cryogenic liquefied gas, such as liquefied hydrogen, the thermal insulation performance of the thermal insulation container plays a very important role.

 In the design of the heat insulation container, a heat insulation technique for preventing the liquefied gas from boiling due to heat transfer from the outside and a leak prevention technique for preventing the leakage of the liquefied gas are very important. In particular, liquefied hydrogen has a vapor pressure higher than atmospheric pressure and is approximately -253 deg. Due to its boiling temperature, the cargo hold for storing and storing these liquefied hydrogens is made of materials that can withstand extremely low temperatures, such as aluminum, stainless steel, 35% nickel steel, etc. It had to be designed with thermal insulation to prevent thermal intrusion.

In the design of thermal insulation containers, leak prevention techniques for preventing the leakage of liquefied gas are very important. In consideration of this, the barrier structure of the cargo hold for transporting cryogenic fluid is sequentially combined with a primary barrier, an upper insulation, a secondary barrier and a lower insulation. If a small amount of cryogenic fluid leaks in the primary barrier, it can prevent further leakage of the fluid in the secondary barrier.

The barrier of the cargo hold is usually formed by fixing a plurality of lower insulating materials having the same thickness on the inner wall of the cargo hold, installing a secondary barrier on the lower insulation, and installing an upper insulation and a primary barrier on the upper portion of the secondary barrier. The secondary secondary barrier and the reinforcement panel are formed in the space between the upper part of the upper secondary insulating material and the upper secondary insulating material in the state where the lower insulating material, the secondary barrier and the upper insulating material are integrally bonded to each other and adjacent to the cargo hold inner wall. It can be installed, the primary barrier can be installed on top of the upper insulation.

Korean Unexamined Patent Publication No. 10-2012-0013233 (2012.02.14.)

It is an object of the present invention to provide a liquefied gas cargo hold capable of monitoring the leakage of cracks of liquefied gas due to barrier defects.

According to one aspect of the invention, the primary barrier for preventing the leakage of liquefied gas; A secondary barrier for preliminarily preventing leakage of liquefied gas; An upper insulating wall provided between the primary barrier and the secondary barrier; A lower insulating wall provided between the secondary barrier and the support wall; And a signal generator installed between the secondary barrier and the lower insulating wall and generating a leakage signal in a cryogenic state when the liquefied gas is leaked.

And a transmitter installed between the support wall and the lower insulating wall. The signal generator may generate an alarm signal with electromotive force generated by electromagnetic induction from the transmitter.

The transmitter includes a piezoelectric element that directly or indirectly contacts the support wall and generates electricity by a load of the received liquefied gas, and a first coil assembly electrically connected to the piezoelectric element, wherein the signal generator is in a cryogenic state. A second coil assembly that is converted to a superconductor, and may include an alarm device that is electrically connected to the second coil assembly when the induced current is generated through the first coil assembly.

The lower insulating wall includes a lower insulating panel, a lower first reinforcing panel and a lower second reinforcing panel respectively attached to upper and lower surfaces of the lower insulating panel, and the upper insulating wall is provided on the upper insulating panel and the upper and lower insulating panels. It may include an upper first reinforcing panel and an upper second reinforcing panel respectively attached.

A plurality of the second coil assembly is arranged in a grid between the lower second reinforcing panel and the secondary barrier to form a network, the alarm device is connected to the network and guided to any one of the second coil assembly Can be activated when current is generated.

The liquefied gas cargo hold according to the present invention uses an electromagnetic induction phenomenon generated in the piezoelectric element of the transmitter when the liquefied gas leaks due to a barrier defect, and a superconducting phenomenon generated when the second coil assembly of the signal generator is in a cryogenic state. Thus, it is possible to constantly monitor whether or not the leakage of the liquefied gas.

In addition, the piezoelectric element generates a voltage by the change in the load of the liquefied gas, and therefore, no separate power is required.

1 is a side cross-sectional view of a liquefied gas cargo hold according to a first embodiment of the present invention.
2 is a detailed view of a transmitter and a signal generator according to the first embodiment of the present invention.
3 is a layout view of a signal generator 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 embodiments introduced below are provided as examples to sufficiently convey the spirit of the present invention to those skilled in the art to which the present invention pertains. The invention is not limited to the embodiments described below and may be embodied in other forms. Parts not related to the description are omitted in the drawings in order to clearly describe the present invention, in the drawings, the width, length, thickness, etc. of the components may be exaggerated for convenience. Like numbers refer to like elements throughout.

1 is a side cross-sectional view of a liquefied gas cargo hold according to a first embodiment of the present invention, and FIG. 2 shows a detailed view of a transmitter and a signal generator according to the first embodiment of the present invention.

The liquefied gas cargo hold according to the first embodiment of the present invention is used for storing and / or transporting cryogenic liquefied gas. Liquefied gas is made of liquid by cooling or compressing gas, and includes liquefied natural gas (LNG), liquefied petroleum gas (LPG), dimethyl ether (DME), and the like. .

LNG carriers, LNG carriers, LNG Regasification Vessel carriers, LPG carriers, or ethylene carriers are used to transport liquefied gas cargoes, Floating Storage Regasification Units (FSRUs), Floating Production Storage Offloading (FPSO), It is also applied to offshore floating facilities that store or produce liquefied gas cargoes such as BMPP (Barge Mounted Power Plant) or have vaporization facilities. In addition, the liquefied gas cargo hold includes those installed on land as well as those used for installation for storing or producing liquefied gas. Hereinafter, the membrane-type cargo hold of the liquefied gas cargo hold will be described as an example.

The liquefied gas cargo hold surrounds a space capable of accommodating liquefied gas and insulates the primary barrier 400 directly in contact with the liquefied gas, and the heat insulation walls 100 and 300 surrounding the primary barrier 400 to insulate the liquefied gas from the outside. And a secondary barrier 200 provided between the heat insulating walls 100 and 300 of the two-layer structure. Further, the liquefied gas cargo hold may have a three-layer structure as a hydrogen cargo hold.

The primary barrier 400 is to seal the storage space in which the storage fluid is accommodated, and airtightness (or watertightness) is required. Liquefied gases are usually stored in the liquid state because they can be kept at very low temperatures below the boiling point. However, vaporization of some liquefied gases may occur due to changes in temperature or pressure, in which case the pressure inside the cargo hold increases greatly. When the primary barrier 400 penetrates due to such an increase in pressure, liquefied gas in a liquid or gaseous state may flow into the insulation walls 100 and 300. The introduced liquefied gas expands rapidly as the temperature increases, and damages the insulation wall. Damage to the cargo hold is enormous and time-consuming to repair, so the tightness of the barrier is very important.

The primary barrier 400 may use a metal material such as Invar alloy (INVAR), stainless steel (SUS), or aluminum alloy to maintain physical and chemical states even in an ultra low temperature state. The primary barrier 400 may be formed by connecting a plurality of primary barrier 400 sheets, and may be welded to each other to maintain airtightness.

As the method for welding the primary barrier 400, various welding methods used in the related art may be used, and include overlap welding or butt welding. In addition, an automatic welding device using a method such as laser welding or plasma welding may be used to improve the welding quality and reduce the work deviation to obtain uniform quality. Since overlap welding, butt welding, laser welding, or plasma welding is a well known technique in the related art, a detailed description thereof will be omitted.

The primary barrier 400 is exposed to rapid contraction and expansion because it is in direct contact with the cryogenic storage fluid. The primary barrier 400 may be destroyed by repeated accumulation of fatigue and thermal expansion, or may damage the airtightness due to breakage of the welded portion when thermal contraction occurs. Because of this problem, primary barrier 400 includes primary barrier corrugations 410 to have low in-plane stiffness. The primary barrier crimp 410 reduces the thermal stress at the weld site by elastically deforming the shape corresponding to the thermal stress.

The primary barrier 400 includes a first pleated portion 411 and a second pleated portion 412 disposed in parallel and in parallel with each other. Thermal stress acting in the in-plane direction of the primary barrier 400 can be resolved by such primary barrier wrinkles 410.

The heat insulation walls 100 and 300 include heat insulation walls 100 and 300 installed in the plane portion and heat insulation walls (not shown) installed in the corner portion. The corner part connects the planar parts arranged at different angles, and includes a corner part to which heat insulating walls of two different directions are connected, and a vertex part to which heat insulating walls of three different directions are connected to each other. Hereinafter will be described based on the heat insulating walls (100,300) installed in the flat portion.

Insulation panels 110 and 310 are generally made of lightweight materials such as polyurethane foam (PUF, Polyurethane Form) or reinforced polyurethane foam (R-PUF, Reinforced PUF). It can be insulated from the outside and kept in a cryogenic state. At this time, the heat insulating wall is generally made of a double heat insulating structure including an upper heat insulating panel 310 and a lower heat insulating panel 110 for the purpose of improving heat insulating performance and ease of repair.

The gap insulation material 111 may be inserted between the heat insulation panels 110 and 310. This may be a heat insulating material that can fill the gap between the lower insulating panel (110). The gap insulation material 111 may be provided between the lower insulation wall 100 after the lower insulation wall 100 is installed on the hull support wall 10. In this case, the support wall 10 may be an inner hull and support the load of the storage fluid, and the insulation wall 100 may be fixed to the support wall 10.

The lower insulation panel 110 may be coupled to the lower first reinforcement panel 120 on a bottom surface thereof so as to be firmly fixed to the support wall 10. The lower first reinforcement panel 120 may be plywood, or the like, and may be attached to the bottom surface of the lower insulation panel 110 using an adhesive such as epoxy glue. That is, the lower first reinforcement panel 120 allows the lower insulation panel 110 to be fixed to the support wall 10, wherein the support wall 10 has a stud bolt for coupling the lower insulation panel 110 to the support wall 10. Not shown) may be welded.

In addition, between the lower first reinforcement panel 120 and the support wall 10, a mastic 11 having an adhesive force and / or a level pad 12 for adjusting a step may be interposed. In particular, since the mastic 11 has adhesive strength and elasticity at the same time, the support wall 10 and the lower insulation panel 110 may be combined with each other to mitigate shocks transmitted to each other.

The plurality of lower insulating panels 110 may be disposed adjacent to each other, for example, may be disposed in a lattice shape. The lattice shape means that the lower insulation panels 110 are disposed not only adjacent to each other in the first direction but also adjacent to each other in a second direction perpendicular to the first direction.

The lower insulation panel 110 may have a lower second reinforcement panel 130 coupled to the upper portion of the lower insulation panel 110 to fix the secondary barrier 200. The lower second reinforcement panel 130 may use plywood or the like, and may be attached to an upper surface of the lower insulation panel 110 using an adhesive such as epoxy glue. The secondary barrier 200 may be coupled to the secondary barrier fixing member 160 provided on the lower second reinforcement panel 130 by welding or the like to be fixed to the lower second reinforcement panel 130.

The insulation walls 100 and 300 may include a secondary barrier 200 interposed between the upper insulation panel 310 and the lower insulation panel 110. The secondary barrier 200 may greatly reduce the time and cost required for repair by protecting the lower insulation panel 110 when the primary barrier 400 is penetrated.

The secondary barrier 200 is made of the same material as the primary barrier 400, such as invar alloy (INVAR), stainless steel (SUS), or an aluminum alloy, or rigid triplex and supple triplex (supple triplex) may be used.

Adhesive manufacturing method and welded manufacturing method are used according to the difference in the method of coupling the secondary barrier 200 to the lower insulating panel 110. Although not shown in the drawings, the adhesive manufacturing method attaches a rigid triplex using an adhesive such as epoxy glue on the lower insulation panel 110, and seals by closing a rigid triplex by connecting the adjacent triplex with a triple triplex. You can complete the state. The shuffle triplex may also be attached onto the rigid triplex by an adhesive.

The secondary barrier 200 may include a secondary barrier corrugation 210 (corrugation) to have a low in-plane stiffness. The secondary barrier pleats 210 reduce the thermal stress at the weld site by elastically deforming the shape corresponding to the thermal stress. And the secondary barrier wrinkles 210 may be formed by a press method or the like.

The wrinkles 210 may be provided in the secondary barrier 200 so that thermal stress acting in the in-plane direction of the secondary barrier 200 may be eliminated. In addition, the secondary barrier wrinkles 210 provided on the secondary barrier 200 may be convex downward toward the lower insulation panel 110. At this time, the lower second reinforcement panel 130 is provided with a groove for accommodating the secondary barrier wrinkle portion 210 of the secondary barrier 200 can avoid the interference with the secondary barrier wrinkle portion 210. . The groove may be formed on the upper surface of the lower second reinforcement panel 130 or may be provided to penetrate the lower second reinforcement panel 130.

The secondary barrier 200 may be fixed to the secondary barrier fixing member 160 provided on the lower insulation panel 110. In particular, when the lower second reinforcement panel 130 is provided, the secondary barrier fixing member 160 may be coupled to the lower second reinforcement panel 130. The secondary barrier fixing member 160 may be mechanically coupled to the lower second reinforcement panel 130 by rivets, and may be made of metal such as SUS and welded to the secondary barrier 200.

In addition, the secondary barrier fixing member 160 may be provided in a strip shape, and may be arranged in different directions to form an intersection portion. For example, it may be provided in a strip shape in two directions perpendicular to each other. The secondary barrier fixing member 160 may be disposed parallel to the edge of the lower insulating panel 110. In addition, the secondary barrier fixing member 160 may be provided as one strip or may be provided so that several strips are continuously connected.

In addition, when the secondary barrier 200 is welded to the fixing member 160, a process of checking whether airtightness is ensured may be performed when welding is completed. As the inspection process, a method of injecting a test gas between the secondary barrier 200 and the lower insulation panel 110 and checking whether the test gas leaks to the outside may be used. If the inspection gas is detected from the outside as a result of the inspection, it is determined that the welding state of the portion is inferior and rewelding. If it is determined that the airtightness as a result of the inspection proceeds to the process of installing the upper insulating wall (300).

The transmitter 500 is in contact with the support wall 10 directly or indirectly, the piezoelectric element 520 for generating electricity by the load of the received liquefied gas, the first coil assembly 510 electrically connected to the piezoelectric element 520. It may include. Since the transmitter 500 generates power by itself using electromotive force generated by sloshing of liquefied gas or the like, there is an advantage of not requiring a separate power source.

Piezoelectric element 520 (piezoelectric effect element) is a device using a crystal, piezoelectric ceramics, etc., which generates voltage when subjected to mechanical stress, and distortion occurs when applied to a voltage. This change (piezoelectric effect), on the contrary, may be a device having the property of expanding or contracting when a voltage is applied. The piezoelectric element 520 may be provided between the mastic 11 provided on the support wall 10 and the lower insulating wall 100 in a plate shape to generate a voltage by a change in load of the liquefied gas.

The first coil assembly 520 may be a disc-shaped member having a coil that operates at a voltage generated in the piezoelectric element 520. The first coil assembly 520 may generate an induction current in the second coil assembly 620 by being positioned on the same line in the height direction as the second coil assembly 620 to be described later. Energy transfer between the first coil assembly 520 and the second coil assembly 620 may be based on an electromagnetic induction law.

The signal generator 600 may include a second coil assembly 610 that is converted to a superconductor in a cryogenic state, and an alarm device 620 that is electrically connected to and operated when an induction current is generated in the second coil assembly 610. . In this case, the conversion of the second coil assembly 620 into the superconductor in the cryogenic state may be performed by the superconductor in which the superconductivity of the electrical resistance approaches zero at a very low temperature appears.

Referring to the operation of the transmitter 500 and the signal generator 600 in detail as follows. The transmitter 500 and the signal generator 600 are provided to detect crack leakage of the liquefied gas. For example, the electromotive force generated by the transmitter 500 is transmitted to the signal generator 600 using the electromagnetic induction law, and the signal generator 600 operates the alarm device 620 using this to determine whether liquefied hydrogen is leaked. To monitor.

In detail, first, when the ship 500 stores the liquefied gas, the transmitter 500 generates a change in the magnetic field by flowing a current through the first coil assembly 510 using the piezoelectric element 520. The liquefied gas in the cargo hold constantly flows during operation to generate a load, and stress caused by the load of the liquefied gas is concentrated in the mastic 11, and electricity generated from the piezoelectric element 520 is transferred to the first coil assembly 510. Delivered.

The current flow to the first coil assembly 510 is transmitted to the second coil assembly 610 far away by the electromagnetic induction phenomenon, the electricity generated in the second coil assembly 610 is alarm device 620, for example, high frequency Activate the device. Here, the second coil assembly 610 remotely operated is not normally operated, but when the liquefied hydrogen leaks into the cryogenic state, a superconducting phenomenon occurs and sufficient current flows due to the electromagnetic induction phenomenon so that the alarm device 620 operates. Form.

In other words, when water leaks in the primary barrier 400, the liquefied hydrogen leaks to reach the secondary barrier 200. Around the secondary barrier 200 adjacent to the leaked liquefied hydrogen is a very low temperature of -253 degrees Celsius, and the second coil assembly 610 on the back is a superconductor. Since the resistance is lost, the induced current is easy to be generated, whereby the alarm device 720, that is, the high frequency generator operates to notify that the crack is generated in the barrier.

3 is a layout view of a signal generator according to a second embodiment of the present invention. FIG. 5 is a plan view illustrating that the lower insulation walls may be disposed in a lattice shape, and the second coil assemblies 711, 712, and 713 may be provided above the lower second reinforcement panel 130 while the second barrier is removed. .

Referring to the drawings, a plurality of second coil assemblies 711, 712, 713 are arranged in a lattice form between the lower second reinforcement panel 130 and the secondary barrier 200 to form a connection network, and an alarm device 720. ) Is connected to the network and may be activated when an induced current is generated in any one of the second coil assemblies 711, 712, 713. That is, the second coil assembly is not provided one-to-one with the alarm device, and by connecting the plurality of second coil assemblies arranged in a grid with one alarm device, the front surface of the cargo hold of a large area can be monitored at the same time.

Although the present invention has been described with reference to one embodiment shown in the accompanying drawings, this is merely exemplary, and those skilled in the art may realize various modifications and other equivalent embodiments therefrom. I can understand. Therefore, the true scope of the invention should be defined only by the appended claims.

10: support wall 11: mastic
12: level pad 100: lower insulation wall
110: lower insulation panel 111: crevice insulation
120: lower first reinforcement panel 130: lower second reinforcement panel
160: secondary barrier fixing member 200: secondary barrier
210: secondary barrier wrinkle portion 300: upper insulation wall
310: upper insulation panel 320: upper first reinforcement panel
330: upper second reinforcement panel 400: primary barrier
410: primary barrier wrinkle portion 411: first wrinkle portion
412: second wrinkle portion 500: transmitter
520: piezoelectric element 510: first coil assembly
600: signal generator 610: second coil assembly
620: alarm device 700: signal generator
711, 712, 713: second coil assembly 720: alarm device

Claims (5)

A primary barrier to prevent leakage of liquefied gas;
A secondary barrier for preliminarily preventing leakage of liquefied gas;
An upper insulating wall provided between the primary barrier and the secondary barrier;
A lower insulating wall provided between the secondary barrier and the support wall;
A transmitter installed between the support wall and the lower insulation wall; And
And a signal generator installed between the secondary barrier and the lower insulating wall and generating a leakage signal in a cryogenic state when liquefied gas leaks.
The transmitter includes a piezoelectric element in direct or indirect contact with the support wall and generating electricity by the load of the received liquefied gas, and a first coil assembly electrically connected to the piezoelectric element,
The signal generator includes a second coil assembly that is converted to a superconductor in a cryogenic state, and an alarm device that is electrically connected to and operated when an induced current is generated in the second coil assembly through the first coil assembly. A liquefied gas cargo hold that generates an alarm signal with electromotive force generated by electromagnetic induction. delete delete A primary barrier to prevent leakage of liquefied gas;
A secondary barrier for preliminarily preventing leakage of liquefied gas;
An upper insulating wall provided between the primary barrier and the secondary barrier;
A lower insulating wall provided between the secondary barrier and the support wall;
A transmitter installed between the support wall and the lower insulation wall; And
And a signal generator installed between the secondary barrier and the lower insulating wall and generating a leakage signal in a cryogenic state by electromotive force generated by electromagnetic induction from the transmitter when liquefied gas leaks.
The lower insulation wall includes a lower insulation panel, a lower first reinforcement panel and a lower second reinforcement panel respectively attached to upper and lower surfaces of the lower insulation panel.
The upper insulation wall includes an upper insulation panel, an upper first reinforcement panel and an upper second reinforcement panel respectively attached to upper and lower surfaces of the upper insulation panel.
The transmitter is installed between the support wall and the lower first reinforcement panel,
The signal generator is a liquefied gas cargo hold installed between the lower second reinforcement panel and the secondary barrier. The method of claim 1,
The second coil assembly is arranged in a plurality of lattice shape to form a connecting network,
The alarm device is connected to the connection network is a liquefied gas cargo hold that is operated when an induced current occurs in any one of the second coil assembly.

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