KR20130033470A - Reinforcement structure for insulation panel of liquefied natural gas cargo containment system - Google Patents

Abstract

PURPOSE: A reinforcement structure for an insulation panel of a liquefied natural gas cargo hold is provided to prevent cracks generated on first and second insulation layers, and to improve reliability at ultralow temperature. CONSTITUTION: A reinforcement structure for an insulation panel(100) of a liquefied natural gas cargo hold comprises a first insulation layer(30), a second barrier wall(40), a second insulation layer(50), a first adhesive layer(70), a second adhesive layer(72), and multiple reinforcing fibers. The first insulation layer is mounted on the rear side of the first barrier wall which contacts to the liquefied natural gas. The second barrier wall is mounted on the rear side of the first insulation layer. The second insulation layer is mounted on the rear side of the second barrier wall. The first adhesive layer is attached to the rear side of the first insulation layer and the surface of the second barrier wall. The second adhesive layer is attached to the surface of the second insulation layer and the rear side of the second barrier wall. Multiple reinforcing fibers are contained in one of the first and second adhesive layers in order to prevent cracks generated on the first and second insulations from being extended to the second barrier wall.

Description

Insulation panel reinforcement structure of LNG cargo hold {REINFORCEMENT STRUCTURE FOR INSULATION PANEL OF LIQUEFIED NATURAL GAS CARGO CONTAINMENT SYSTEM}

The present invention relates to a cargo containment system (Liquefied Natural Gas, LNG), and more particularly, to an insulation panel reinforcement structure of an LNG cargo hold that can prevent the propagation of cracks generated in the insulation layer of the insulation panel. It is about.

Cargo holds of LNG carriers are preferred for membrane type tanks with larger capacity and easier production than spherical type tanks for storing and transporting cryogenic LNG at -165 ℃. A gas transport system and a Technigaz system developed by the company Gas Transport Et Technigaz (GTT, France) are used for the cargo hold of the membrane type LNG carrier .

The Gaz Transport system is also called the NO 96 Membrane System. Invar steel (Invar, 36% nickel steel), which has a very low thermal expansion, is used for the first and second barriers of the gaz transport system. An insulation box filled with pearlite is installed between the first and second barriers for insulation.

The Technics system is also called the Mark III Membrane System. The first barrier of the Technics system consists of a stainless steel membrane in which corrugations are formed in a lattice form to absorb shrinkage and expansion due to thermal deformation. An insulation panel is installed between the inner wall of the LNG carrier and the first barrier. The heat insulation panel is comprised from a 1st heat insulation layer, a 2nd barrier, and a 2nd heat insulation layer. The first and second heat insulating layers are made of polyurethane foam having excellent heat insulating properties, and the second barrier is made of a triplex membrane and a glass fiber composite.

The gas vaporization rate (BOR, Boil-off Rate) of the Gaz Transport system and the Technics system is known to be similar, but the cost of stainless steel sheet and glass fiber composite material is cheaper and easier to install than the Invar membrane. Technics systems are preferred because of their excellent thermal insulation.

Low-density polymer foams, such as polyurethane foams used to reduce gas evaporation rates in thermal insulation panels of such technology systems, have low stiffness and fracture toughness. Therefore, cracks are likely to occur in the first and second heat insulating layers. Cracks generated in the first and second thermal insulation layers are propagated to the second barrier to lower the tightness and the cryogenic reliability at cryogenic temperatures. In order to improve the fracture toughness, glass fiber is mixed and reinforced with polymer foam. However, when the volume fraction of glass fiber is increased, the thermal insulation performance is reduced and uniform due to the high thermal conductivity of the glass fiber. One quality control is difficult.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. An object of the present invention is to provide a heat insulation panel reinforcement structure of an LNG cargo hold which can prevent the cracks generated in the heat insulation layer from propagating to the second barrier and can improve the reliability at cryogenic temperatures.

A feature of the present invention for achieving the above object is a first heat insulating layer mounted on the back of the first barrier for storing LNG in contact with the LNG; A second barrier mounted on the rear surface of the first heat insulating layer; A second heat insulating layer attached to the rear surface of the second barrier; A first adhesive layer joining the back surface of the first heat insulating layer and the surface of the second barrier; A second adhesive layer bonding the surface of the second heat insulating layer to the back surface of the second barrier; Insulation panel of LNG cargo hold comprising a plurality of reinforcing fibers contained in any one of the first adhesive layer and the second adhesive layer in order to suppress the propagation of the cracks generated in the first and second insulating layer to the second barrier. It is in the reinforcement structure.

Another feature of the present invention includes a first heat insulating layer mounted on a rear surface of a first barrier for contacting LNG and storing LNG; A second barrier mounted on the rear surface of the first heat insulating layer; A second heat insulating layer attached to the rear surface of the second barrier; A first adhesive layer joining the back surface of the first heat insulating layer and the surface of the second barrier; A second adhesive layer joining the surface of the second heat insulating layer and the back surface of the second barrier, the back surface of the first heat insulating layer for suppressing propagation of cracks generated in the first heat insulating layer and the second heat insulating layer to the second barrier. The insulation panel reinforcement structure of the LNG cargo hold in which a plurality of slits are formed on any one of the surfaces of the second heat insulating layer.

The insulation panel reinforcing structure of the LNG cargo hold according to the present invention is a slit formed in the reinforcing fibers or the first and second heat insulating layers included in the adhesive layer that the cracks generated in the first and second heat insulating layers propagate to the second barrier. Is prevented by these components, and the reliability at cryogenic temperature is greatly improved.

1 is a cross-sectional view showing the configuration of the LNG cargo hold is applied to the insulation panel reinforcement structure according to the present invention,
Figure 2 is a cross-sectional view showing a partially expanded insulation panel reinforcement structure according to the invention,
Figure 3 is a partially enlarged cross-sectional view showing another embodiment of the insulation panel reinforcement structure according to the present invention.

Other objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments with reference to the accompanying drawings.

Hereinafter, preferred embodiments of the insulation panel reinforcement structure of the LNG cargo hold according to the present invention will be described in detail with reference to the accompanying drawings.

First, referring to FIG. 1, the LNG cargo hold according to the present invention is installed inside the inner wall 2 constituting the LNG carrier and is contacted with LNG for storage of LNG to support liquid tightness (Liquid Tightness). 10). The first barrier 10 is composed of a plurality of membranes 12 mounted inside the wall 2. The membranes 12 have a plurality of corrugations 14 that are formed to be capable of contraction and expansion due to thermal deformation. The membranes 12 may be constructed of stainless steel. The membranes 12 weld along their edges to join two adjacent membranes 12.

A first panel (Panel) 20 is mounted on the back surface of the first barrier 10. The first panel 20 is made up of a plurality of fly-woods 22 mounted on the back surface of the first barrier 10. The first heat insulating layer 30 is mounted on the back surface of the first panel 20. The first heat insulation layer 30 is composed of a plurality of first unit insulation blocks 32. The first unit insulating blocks 32 are heat insulating materials having excellent heat insulating properties, for example, polyurethane foam, sandwich form, micro-celluloid form, nano-celluloid form, and the like. It may be configured as. And the second barrier 40 is attached to the back surface of the first heat insulating layer 30. The second barrier 40 may be composed of a plurality of triplex membranes 42 or a metal sheet made of stainless steel, aluminum, brass, zinc, or the like. The triplex membranes 42 are formed by bonding a glass fiber composite material to both surfaces of an aluminum foil. The triplex membranes 42 are connected by a plurality of triplex joints 44.

And the second insulating layer 50 is attached to the back surface of the second barrier 40. The second heat insulation layer 50 is composed of a plurality of second unit insulation blocks 52. The second unit insulation blocks 52 are arranged so that the interface of each of the first unit insulation blocks 32 and the interface of each of the second unit insulation blocks 52 are shifted from each other to prevent leakage of LNG. The second unit insulation blocks 52 may be formed of polyurethane foam, sandwich foam, micro celluloid foam, nano celluloid foam, or the like. In FIG. 1, the second barrier 40 is mounted on the rear surface of the first heat insulating layer 30 so as to cover the interface between the second unit insulation blocks 52. 40 may be mounted between the first panel 20 and the second heat insulating layer 50 to cover the entire surface of the second heat insulating layer 50. The second panel 60 is attached to the rear surface of the second barrier 40. The second panel 60 may be composed of a plywood (62), a sandwich panel, or the like. The rear surface of the second panel 60 is fixed to the inner surface of the inner wall 2 of the LNG carrier by a mastic (Mastic) 64, a resin rope, and the mastic 64 is composed of epoxy resin. Can be.

In the LNG cargo hold according to the present invention, the first panel 20, the first heat insulating layer 30, the second barrier 40, the second heat insulating layer 50 and the second panel 60 are assembled in advance and the inner wall 2 It is installed in). The back surface of the first heat insulating layer 30 and the surface of the second barrier 40 are joined by the first adhesive layer 70. The surface of the 2nd heat insulation layer 50 and the back surface of the 2nd barrier 40 are joined by the 2nd adhesive bond layer 72. As shown in FIG. The first and second adhesive layers 70 and 72 may be made of epoxy resin. In this way, the second barrier 40 is included between the first and second heat insulating layers 30 and 50 to be assembled in advance, which is referred to as a heat insulating panel 100, a prefabricated heat insulating panel, or a heat insulating sandwich panel. After the insulation panel 100 is installed on the inner wall 2, the first barrier 10 is installed on the surface of the insulation panel 100.

As shown in FIG. 2, a plurality of reinforcing fibers 80 are contained in the first and second adhesive layers 70 and 72. The reinforcing fibers 80 may be composed of glass fibers, aramid fibers, carbon fibers, and polyethylene fibers having higher rigidity than the first and second adhesive layers 70 and 72. The volume fraction of the reinforcing fibers 80 with respect to the first and second adhesive layers 70 and 72 is preferably equal to or greater than the critical volume fraction showing the reinforcing effect. The reinforcing fiber 80 preferably has a volume fraction of 10% or more, for example.

At cryogenic temperatures, the first and second thermal insulation layers 30 and 50 and the second barrier 40 are formed on the first and second thermal insulation layers 30 and 50 having relatively low fracture toughness due to the difference in thermal expansion coefficient and thermal stress. There is a high possibility of cracking. That is, even if the second barrier 40 has high fracture toughness and failure strain, the strain is locally concentrated in the first and second heat insulating layers 30 and 50, and thus the first and second heat insulating layers 30 and 50 are used. It is easy to crack. The cracks of the first and second heat insulating layers 30 and 50 propagate to the second barrier 40 through the first and second adhesive layers 70 and 72.

The insulation panel reinforcement structure of the LNG cargo hold according to the present invention is provided by the reinforcing fibers 80 in which the cracks of the first and second insulation layers 30 and 50 are contained in the first and second adhesive layers 70 and 72. Since propagation to the second barrier 40 is suppressed, reliability at cryogenic temperatures can be improved. In addition, since the first and second adhesive layers 70 and 72 may be reinforced thinly and uniformly by the inclusion of the reinforcing fibers 80, the uniformity of quality may be improved.

3 shows another embodiment of the insulation panel reinforcement structure of the LNG cargo hold according to the present invention. Referring to FIG. 3, another embodiment of the insulation panel reinforcing structure includes a plurality of slits on the back surface of the first heat insulation layer 30 and the surface of the second heat insulation layer 50 adjacent to the front surface and the back surface of the second barrier 40. 90) are formed. The slits 90 may be used in the heat insulation panel 100 together with the reinforcing fibers 80 described above.

The plurality of slits 90 disperse concentration of strains in the first and second heat insulating layers 30 and 50 due to cracks generated in the first and second heat insulating layers 30 and 50. Therefore, propagation of the cracks generated in the first and second heat insulating layers 30 and 50 to the second barrier 40 is suppressed. Since the thermal stress is mainly generated in the plane direction of the second barrier 40, the direction of the slits 90 is preferably formed perpendicular to the first and second heat insulation layers 30 and 50, that is, in the thickness direction. It may be formed in any direction capable of suppressing cracks propagating to the barrier 40. Further, although the slits 90 are preferably formed around the first and second adhesive layers 70 and 72, the positions of the slits 90 may be changed appropriately depending on the position where the thermal stress is concentrated.

The embodiments described above are merely illustrative of the preferred embodiments of the present invention, the scope of the present invention is not limited to the described embodiments, those skilled in the art within the spirit and claims of the present invention It will be understood that various changes, modifications, or substitutions may be made thereto, and such embodiments are to be understood as being within the scope of the present invention.

10: first barrier 20: first panel
30: first heat insulating layer 40: second barrier
50: second heat insulating layer 60: second panel
70: first adhesive layer 72: second adhesive layer
80: reinforcing fiber 90: slit
100: insulation panel

Claims (3)

A first heat insulating layer mounted on a rear surface of the first barrier in contact with the liquefied natural gas and storing the liquefied natural gas;
A second barrier mounted on a rear surface of the first heat insulating layer;
A second heat insulating layer mounted on a rear surface of the second barrier;
A first adhesive layer bonding the back surface of the first heat insulating layer to the surface of the second barrier;
A second adhesive layer bonding the surface of the second heat insulating layer to the back surface of the second barrier;
It includes a plurality of reinforcing fibers contained in any one of the first adhesive layer and the second adhesive layer in order to suppress the propagation of the crack generated in the first heat insulating layer and the second heat insulating layer to the second barrier. Insulation panel reinforcement structure of LNG cargo hold. The insulation panel reinforcement structure of claim 1, wherein the plurality of reinforcing fibers have a higher rigidity than the first adhesive layer and the second adhesive layer. A first heat insulating layer mounted on a rear surface of the first barrier in contact with the liquefied natural gas and storing the liquefied natural gas;
A second barrier mounted on a rear surface of the first heat insulating layer;
A second heat insulating layer mounted on a rear surface of the second barrier;
A first adhesive layer bonding the back surface of the first heat insulating layer to the surface of the second barrier;
A second adhesive layer joining the surface of said second heat insulating layer and the back surface of said second barrier,
Liquefaction in which a plurality of slits are formed on any one of a rear surface of the first heat insulating layer and a surface of the second heat insulating layer in order to prevent the cracks generated in the first heat insulating layer and the second heat insulating layer from propagating to the second barrier. Insulation panel reinforcement structure of natural gas hold.

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