JPH10246397A - Ceiling cold insulator of cryogenic liquefied gas underground tank and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a specified cold insulation function so as to be securable by preventing a local crack and any possible drop in adiabatic performance in diffusing the heat over the whole area when a cryogenic liquid comes into contact with the local part of a surface at a side facing to the inside of a tank. SOLUTION: A first sheetlike face bar 2 being composed of laminately unifying those of aluminum foil 2a, stiffened liner 2c and glass fiber cloth 2e in a bloc is set up in a surface at a side facing to the inside of a cryogenic liquefied gas underground tank, out of both sides of a hard urethane material so as to make the aluminum foil 2a face to the inside of this tank, while a second sheetlike face member 3 used with two stiffened liners 3b and 3d in order to take a tension balance with the first sheetlike face bar 2 is set up in the surface on the other, and these sheetlike face members 2 and 3 are integrally bonded and fixed by means of self-adhesive strength inherent in the hard urethane material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-temperature liquefied gas underground tank that is exposed and exposed on the ground surface, among underground tanks installed and constructed underground to store low-temperature liquefied gas such as LNG and LPG. The present invention relates to a cooling material for a ceiling of a tank and a method for manufacturing the same.

[0002]

2. Description of the Related Art FIG. 5 shows an example of a low-temperature liquefied gas, LNG.
FIG. 6 is a schematic plan view showing an installation construction state of the underground tank, and FIG. 6 is a schematic plan view thereof. The tank body 10 has a cylindrical side wall material 13 in which a stainless steel 12 is adhered to an inner peripheral surface of a hard urethane material 11. And is installed and constructed underground with a bottomed cylindrical shape by a bottom wall material 14. At the upper end of the bottomed cylindrical tank body 10, a structural steel frame 15 radially arranged in a plan view is interposed. And many arc-shaped ceiling insulation materials 16
The dome-shaped ceiling 17 exposed on the ground surface by closely arranging them is constructed.

[0003] The ceiling cold insulator 16 of the low-temperature liquefied gas underground tank installed and constructed as described above has an inner surface in contact with a cryogenic liquid or a low-temperature gas of a low-temperature liquefied gas such as LNG.
Under the severe conditions that the outside surface is in contact with the atmosphere, the temperature difference between inside and outside is very large, and the temperature difference between the inside and outside is further expanded due to the temperature change of the atmosphere between daytime and nighttime, and a large thermal shock is received. Very high heat insulation performance and thermal shock resistance are required in order to ensure a predetermined cooling function even under such severe use conditions.

Conventionally, as a cold insulator 16 for a low-temperature liquefied gas underground tank meeting such a demand, a rigid urethane material 18 having a plurality of thicknesses is cut out from a rigid urethane slab foam as shown in FIG. An adhesive such as urethane is applied to both front and back surfaces of the cut board-shaped hard urethane material 18, and a low-temperature resistant glass cloth 19 is used. As for the thick ceiling cold insulator 16A, a hard urethane material 18A cut into a board shape with a different thickness from a hard urethane slab foam is polymerized and bonded to a glass cloth stuck ceiling cold insulator 16 as shown in FIG. A fixed one was used.

[0005]

Since the inner surface of the conventional cold insulation material of a low-temperature liquefied gas underground tank is bonded with glass cloth, the cryogenic liquid may be in contact with a local portion of the inner surface. In such a case, the temperature difference between the wetted part and the other part becomes extremely large, and in addition, a large temperature difference between the inside and the outside adds a strong force to the wetted part despite the presence of the glass cloth. There is a problem that the thermal shock tends to cause localized cracking at the location due to concentrated action, or even if the cracking does not occur, the heat insulation performance is locally reduced and the predetermined cooling function cannot be performed. .

In terms of manufacturing, a step of cutting out a plurality of board-shaped hard urethane materials 18 and 18A from a hard urethane slab foam and applying an adhesive to the cut hard urethane material 18 to form a glass cloth 19
Is necessary, and for a thick material, a step of polymerizing another hard urethane material 18A and bonding and fixing the same is also required. Therefore, the productivity is lacking and the production cost becomes extremely high. In addition, since the inner surface of the cold insulator 16 is glass cloth adhered and has a difference in appearance from the stainless steel 12 on the inner surface of the side wall material 13 of the underground tank body 10, the finished surface in appearance is But it was not preferable.

The present invention has been made in view of the above circumstances, and when a cryogenic liquid comes into contact with a local part of the inner surface, the heat is diffused to the whole area to cause local cracking and heat insulation. A main object of the present invention is to provide a cooling material for a ceiling of a low-temperature liquefied gas underground tank, which can prevent a decrease and can secure a predetermined cooling function.

Another object of the present invention is to make it possible to continuously produce a ceiling heat insulating material having an excellent heat insulating function as described above up to an extremely large one having a maximum thickness, thereby greatly reducing the manufacturing cost. It is an object of the present invention to provide a method for manufacturing a cold insulator for a low-temperature liquefied gas underground tank.

[0009]

In order to achieve the above-mentioned main object, according to the first aspect of the present invention, there is provided a low-temperature liquefied gas underground tank having at least one of a hard urethane material and a low-temperature material. On the surface facing the inside of the liquefied gas underground tank, a sheet-like surface material formed by laminating and integrating a metal thin film, a strong liner and a glass cloth is arranged so that the metal thin film faces the inside of the low-temperature liquefied gas underground tank. It is characterized by being adhered and fixed.

According to the first aspect of the present invention, in the usage mode of the cold insulator, the cryogenic liquid comes into contact with a local portion of the surface of the sheet-like surface material facing the inside of the tank and is rapidly cooled. In such a case, the liquid is prevented from penetrating into the hard urethane material side, and the cold heat is diffused to the entire surface through the good heat transfer performance of the metal thin film to reduce the temperature difference between the surfaces facing the inside of the tank. It becomes possible. As a result, a predetermined cooling function can be ensured by preventing the ceiling cooling material from being locally cracked or the heat insulating performance from being locally reduced. Further, since the surface facing the inside of the tank is a metal thin film, there is almost no difference in appearance between the tank body and the inner surface of the side wall member, and a good finished appearance can be obtained.

[0011] In the cooling material for a ceiling of a low-temperature liquefied gas underground tank having the above-mentioned structure, as set forth in claim 2, a sheet-like surface material adhered and fixed to the other surface of the hard urethane material and to a surface facing the inside of the tank. When adhesively fixing a sheet-like surface material using a strong liner to balance tension with the cryogenic liquid, the cryogenic liquid came into contact with the sheet-like surface material on the side facing the inside of the tank and the shrinkage force was exerted At that time, the shrinkage force can be distributed almost uniformly over the entire area of the ceiling cold insulator to balance the ceiling cold insulator, thereby preventing deformation such as warping of the ceiling cold insulator.

As the metal thin film of the sheet-like face material in the cold insulation material of the low-temperature liquefied gas underground tank, aluminum foil is most preferable, but stainless steel foil or iron foil may be used. Any material can be used as long as it can be cut when the ceiling cooler is bolted to the tank ceiling.

Further, in order to achieve the above-mentioned other object,
A method for manufacturing a ceiling cold insulator for a low-temperature liquefied gas underground tank according to the invention described in claim 4 is a sheet-like face material obtained by laminating and integrating a metal thin film, a strong liner and a glass cloth, and at least a strong liner. While continuously transporting the sheet-like face material using
A hard urethane is injected and foamed between the two sheet-like face members, and the two sheet-like face members and the hard urethane material are integrally bonded and fixed by the self-adhesive force of the hard urethane.

According to the fourth aspect of the present invention,
By using a liner with strong stiffness as the two sheet-like facing materials, the self-adhesive strength of the hard urethane is obtained by bonding both the sheet-like surface materials and the hard urethane injected and foamed between the two sheet-like surface materials. Utilizing a sandwich panel manufacturing line that has already been put into practical use as a thermal insulation sandwich panel manufacturing facility for the production of ceiling cold insulators integrated by Continuous production up to a thickness of 250 mm becomes possible. Thereby, the secondary processing of cutting out a plurality of thicknesses of the board-shaped hard urethane material from the hard urethane slab foam and attaching a glass cloth or the like to the cut hard urethane material via an adhesive, and further, a thick material This eliminates the need for a separate process of polymerizing and bonding a hard urethane material to produce, and can greatly reduce manufacturing costs. In addition, since the metal thin film and the glass cloth are laminated and integrated on one sheet-like surface material with the above-mentioned liner interposed therebetween, the produced ceiling cold insulating material is laminated with the sheet-like surface material having a low-temperature liquefied gas. By arranging and using it so as to face the inside of the underground tank, similar to the invention according to the above-described claim 1, it does not cause local cracking or local deterioration in heat insulation performance, Thus, a predetermined cooling function can be ensured without causing deformation.

Further, in the method of manufacturing a ceiling cold insulator for a low-temperature liquefied gas underground tank according to claim 4, the method according to claim 5.
As described in the above, when adopting means for applying an adhesive subjected to corona discharge treatment on the surface of the sheet-like surface material to be bonded to the hard urethane material, the sheet-like surface material to the hard urethane material It is possible to remarkably improve the production yield of the ceiling heat insulating material having the above-described excellent heat insulating performance and thermal shock performance by strengthening the adhesive force.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a main part showing a ceiling cold insulator of a low-temperature liquefied gas underground tank according to the present invention,
The first and second sheet-like face materials 2 and 3 are bonded and fixed to the front and back surfaces of the hard urethane material 1 formed into a required size, thickness and shape, and the overall thickness t of the ceiling cold insulator 4 is reduced. It is formed to be 250 mm.

As shown in FIG. 5, when the low-temperature liquefied gas underground tank is framed at the upper end of the bottomed cylindrical tank body 10, the sheet-like face members 2 and 3 face the inside of the tank body 10. As shown in FIG. 2, the first sheet-like face material 2 bonded and fixed to the surface of the hard urethane material 1 on the side
0 μm aluminum foil 2 a, 20 μm polyethylene adhesive 2 b and strong liner 2 c such as kraft paper and 20 μm
m polyethylene adhesive 2d, glass cloth 2e, and corona discharge treated 20 μm polyethylene adhesive 2
The aluminum foil 2a is arranged so as to face the inside of the tank body 10 and is bonded and fixed to the hard urethane material 1.

On the other hand, when constructed on the upper end of the bottomed cylindrical tank body 10 in the low-temperature liquefied gas underground tank, the second sheet-like face material adhered and fixed to the surface of the hard urethane material 1 on the side facing the atmosphere. As shown in FIG. 3, reference numeral 3 denotes a stiff liner 3a such as kraft paper, a 20 μm polyethylene adhesive 3b, and a stiff liner 3c such as kraft paper.
It is made by laminating and integrating a 0 μm polyethylene adhesive 3d, and the tension between the first sheet-like face material 2 and the first sheet-like face material 2 is balanced by the presence of the two liners 3a and 3c.

The ceiling cold insulator 4 of the low-temperature liquefied gas underground tank as described above has a maximum thickness t by utilizing a sandwich panel continuous production line which has already been put into practical use as an insulated sandwich panel production facility. 250m
m, and can be continuously molded. The production method and the continuous production equipment will be described below.

FIG. 4 shows a schematic configuration of a sandwich panel continuous production line which has already been put into practical use. The first and second sheet-like surfaces respectively wound on a pair of upper and lower uncoilers 20 and 21 are shown. The materials 2 and 3 are pulled out from the uncoilers 20 and 21 while being vertically opposed to each other by the double conveyors 22 and 23, and are continuously conveyed in line in a synchronized state. At the time of this line-shaped continuous conveyance, first, the first and second sheet-like face materials 2,
The protective films 24, 25 made of resin are polymerized on the non-opposite outer surfaces of No. 3 and transferred into roll forming machines 26, 27, respectively, and roll-formed into a predetermined shape, for example, a double-sided corrugated or single-sided flat / other-sided corrugate. rear,
It is moved through the preheat oven 28 and preheated.

Subsequently, the preheated first and second sheet-like face materials 2 and 3 are carried into a hard urethane injection / foaming chamber 29, where they are passed through a foaming machine 30. While urethane is injected between 3 and 3,
The first and second sheet-like face members 2 and 3 and the hard urethane material 1 are integrated by the self-adhesive force of the hard urethane by being carried into the curing oven 31 including the double conveyors 22 and 23 and heated. Adhesively fixed to the
By cutting the first and second sheet-like surface materials 2 and 3 by the surface material cutters 32 and 33 disposed in front of the roll forming machines 26 and 27, a long ceiling cold insulator 4A of an arbitrary length can be formed. It is continuously formed.

The long cooling material 4A having a predetermined size is manufactured from the long cooling material 4A continuously formed to an arbitrary length by the sizing cutter device 34, and the manufactured cooling material 4 is fed horizontally. By 35, the paper is laterally stacked from the above continuous transport line. Although not shown, side tapes are conveyed in parallel to the side of the injection foaming chamber 29 and the double conveyors 22 and 23 via side holding belt conveyors, so that the hard urethane injection stock solution and the side of the foamed urethane are not shown. Leakage to the side is prevented. In addition, this sandwich panel continuous production line can continuously form a panel having an overall thickness of 30 mm to 250 mm.

[0023]

As described above, according to the first aspect of the present invention, the surface facing the inside of the tank in the use mode is
Since the sheet-like surface material, which is made by laminating a metal thin film, a strong liner and a glass cloth, is bonded and fixed, only the glass cloth absorbs the thermal shock acting on the ceiling insulation due to the temperature difference between the inside and outside Instead, if the local cold insulation material is rapidly cooled by contact with cryogenic liquid, the innermost thin metal film prevents the liquid from penetrating into the hard urethane material, and diffuses the cold heat over the entire surface to form a tank. The temperature difference on the entire surface facing the inside can be reduced. Therefore, a predetermined cooling function can be ensured by preventing the ceiling heat insulating material from being locally cracked or the heat insulating performance from being locally reduced. Further, since the surface facing the inside of the tank is a metal thin film, there is almost no difference between the appearance of the inner surface of the side wall member of the tank body and an effect that a good finished appearance can be obtained.

In particular, when a sheet-like surface material using a strong liner is bonded and fixed to the other surface of the hard urethane material as described in claim 2, the sheet-like surface material facing the inside of the tank is used. Even when the cryogenic liquid comes into contact with the chilled liquid and the shrinkage force is applied, the shrinkage force is distributed almost uniformly over the entire area of the ceiling insulation material, and the deformation of the ceiling insulation material such as warpage is generated. To prevent and maintain a predetermined cooling function for many months.

According to the fourth aspect of the present invention, a ceiling insulation material having a maximum thickness of 250 mm is utilized by utilizing a sandwich panel manufacturing line which has already been put into practical use as a heat insulating sandwich panel manufacturing facility. Can be continuously manufactured, so that, as in the prior art, a step of cutting out a plurality of thicknesses of a board-shaped hard urethane material from a hard urethane slab foam and a glass through an adhesive to the cut hard urethane material The secondary processing of pasting a cloth or the like, and the polymerization bonding step of another hard urethane material for making a thick product are not required, and the production cost can be significantly reduced. In addition, a sheet-like surface material in which a metal thin film and a glass cloth are laminated and integrated on one side of a hard urethane material in the manufactured ceiling cold insulator is sandwiched by a firm liner, so that it is bonded and fixed. By arranging and using the ceiling heat insulating material such that the sheet-like face material of the laminated structure faces the inside of the low-temperature liquefied gas underground tank, similar to the inventions according to the above-mentioned claims 1 and 2, local cracking is achieved. There is an effect that a predetermined cooling function can be ensured for a long period of time without deformation such as local deterioration of heat insulation performance and further, warpage or the like.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of a low-temperature liquefied gas underground tank according to the present invention, showing a part of a ceiling cold insulator in a partially broken state.

FIG. 2 is an enlarged vertical cross-sectional view of a first sheet-like face material in the above-mentioned ceiling cold insulating material.

FIG. 3 is an enlarged vertical cross-sectional view of a second sheet-like face material in the ceiling cold insulating material.

FIG. 4 is a schematic configuration diagram of a continuous sandwich panel production line used for producing a ceiling cold insulator for a low-temperature liquefied gas underground tank according to the present invention.

FIG. 5 is a schematic longitudinal sectional view showing an installation and construction state of an LNG underground tank which is an example of a low-temperature liquefied gas.

6 is a schematic plan view of FIG.

FIG. 7 is a perspective view of a main part of a conventional low-temperature liquefied gas underground tank, showing a part of a ceiling cold insulator in a partially broken state.

FIG. 8 is a perspective view of a main part of a conventional low-temperature liquefied gas underground tank, showing a thick part of a ceiling cold insulator in a partially broken state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hard urethane material 2 1st sheet-like face material 2a Aluminum foil (metal thin film) 2b, 2d, 2f, 3b, 3d Adhesive 2c, 3a, 3c Strong liner 2e Glass cloth 3 Second sheet-like face material 4 Ceiling insulation

Claims (5)

[Claims] 1. A sheet-like surface material formed by laminating and integrating a metal thin film, a strong liner, and a glass cloth on at least a surface facing the inside of a low-temperature liquefied gas underground tank among the front and back surfaces of the hard urethane material. A cold insulation material for a low-temperature liquefied gas underground tank, wherein the metal thin film is disposed so as to face the inside of the low-temperature liquefied gas underground tank and is adhered and fixed. 2. A sheet-like surface material using a strong liner for balancing tension with the sheet-like surface material is adhered and fixed to the other surface of the hard urethane material. The cold insulation material for the low-temperature liquefied gas underground tank described. 3. The cold insulation material for a low-temperature liquefied gas underground tank according to claim 1, wherein the metal thin film is an aluminum foil. 4. A sheet-like face material obtained by laminating and integrating a metal thin film, a firm liner and a glass cloth, and at least a sheet-like face material using a strong liner are continuously conveyed in a line shape. A hard urethane is injected and foamed between the two sheet-like face members while foaming, and the two sheet-like face members and the hard urethane material are integrally bonded and fixed by the self-adhesive force of the hard urethane. A method of manufacturing a cold insulation material for liquefied gas underground tanks. 5. The low-temperature liquefied gas underground tank according to claim 4, wherein an adhesive subjected to corona discharge treatment is applied to an adhesive surface side of the sheet-like surface material to the hard urethane material. Production method.