JPH11117543A - Demolishing method for above-ground cylindrical tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a demolishing method for an above-ground type cylindrical tank by integrally dropping inner and outer tank roof structures without requiring a large scaffold. SOLUTION: After removing a cold insulator between the inner and outer tanks, the periphery of the inner tank roof 8 is cut off and it is supported by the outer tank roof 4, coupling jigs 14 are attached across the cutting portion 13 surrounding the outer tank roof 4 thereby permitting the support even in a cut state. Next, pressured air is introduced from a blower 15 to the inside of an inner tank thereby permitting the supporting of the inner and outer tank roofs 4, 8 by air pressure, the coupling jig 14 is removed in this state, and the inner and outer tank roofs 4, 8 are lowered to the ground while supporting them with the air pressure and are disassembled. By doing this, the inner and outer tank roofs 4, 8 can be disassembled on the ground without using a large scaffold thereby reducing the work at a high place and assuring the safety.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of dismantling a ground-type cylindrical tank, in which the roof at the inner and outer tanks is lowered while being supported by air pressure so that work at a high place can be reduced as much as possible and the dismantling can be performed safely and efficiently. It is.

[0002]

2. Description of the Related Art As a tank for storing liquefied natural gas (LNG) or liquefied petroleum gas (LPG), a double-shell cylindrical tank filled with a cooling material between inner and outer tanks is used.

[0003] In such a double-shelled cylindrical tank, while being used for a long period of time, it is corroded from the outside by salt and sulfur contained in the outside air, and also corroded by water mixed in from the inside, and the corroded portion When repairs make regeneration impossible, the entire tank must be dismantled and rebuilt.

Conventionally, when disassembling a double-shell cylindrical tank, work scaffolds are temporarily provided so as to surround the outer tank, a large crane is prepared, and the outer tank roof is sequentially cut to a weight that can be supported by the large crane. Then, dismantling is performed by repeatedly lowering the cut pieces on the ground.

[0005]

However, in such a conventional method of dismantling a double-shell cylindrical tank, a large-scale work scaffold must be temporarily installed around the outer tank, which requires a great deal of time for temporary installation and removal. In addition, there is a problem that dismantling of the inner and outer tank roofs is a work at a high place.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and disassembles by reducing the work in high places as much as possible by lowering the roof of the inner and outer tanks to the ground without requiring a large-scale work platform. It is an object of the present invention to provide a method of disassembling a ground-type cylindrical tank that can be used.

[0007]

In order to solve the above problems,
In the method of dismantling the above-ground cylindrical tank according to claim 1 of the present invention, when disassembling the above-ground double-shell cylindrical tank, after removing the cooling material between the inner and outer tanks, cutting around the inner tank roof. After being supported by the outer tank roof, a connecting jig is attached across the cut part around the outer tank roof, and then pressurized air is introduced into the inner tank to enable the inner and outer tank roof to be supported. After cutting the cutting portion around the tank roof, removing the connecting jig and lowering it while supporting it with air pressure, the inner and outer tank roofs and the inner and outer tank side walls are cut and dismantled. It is.

According to this method of dismantling the above-ground cylindrical tank, after removing the cooling material between the inner and outer tanks, the periphery of the inner tank roof is cut and supported by the outer tank roof. After the connecting jig is attached and straddled, it can be supported even when it is cut, and then pressurized air is introduced into the inner tank so that the inner and outer tank roofs can be supported with air pressure. The roof of the inner and outer tanks is lowered to the ground while being supported by air pressure and dismantled, and the roof of the inner and outer tanks can be dismantled on the ground, making it possible to work at heights without setting up a large-scale work scaffold. It can be safely dismantled by reducing it.

According to a second aspect of the present invention, there is provided a method for dismantling a ground-type cylindrical tank according to the first aspect, further comprising cutting the periphery of the inner tank roof and supporting the outer tank roof with the outer tank roof. An air seal for sealing between the inner tank roof and the inner tank side wall is provided around the inner tank roof.

According to this method of dismantling the above-ground cylindrical tank, an air seal is attached around the inner tank roof to seal the air around the inner tank, so that the support by the air pressure is further ensured to lower safely. Will be able to do it.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for dismantling a ground-type cylindrical tank according to the present invention will be specifically described below with reference to the drawings. 1 and 2 are a first half process diagram and a second half process diagram according to an embodiment in which the above-described method of dismantling a ground-type cylindrical tank of the present invention is applied to a double-shell low-temperature storage tank.

In the double-shell low-temperature storage tank to which the above-mentioned ground-type cylindrical tank dismantling method is applied, an outer tank bottom plate 2 is provided on a foundation 1 provided on the ground or the like, and a cylindrical outer tank side plate 3 is provided therearound. It is welded, the upper part is covered with an outer tank roof 4, and an inner tank bottom plate 6 is provided in the outer tank via a bottom heat insulating material 5,
A cylindrical inner tank side plate 7 is welded to the periphery thereof, the upper part of which is covered with an inner tank roof 8 and a suspension rod 9 attached to the outer tank roof 4.
, And is filled with a cooling material 10 between the inner and outer tanks.

The disassembly of such a double-shell low-temperature storage tank is performed as follows. As a preparation, it is necessary to completely discharge the storage liquid in the storage tank and discharge the evaporative gas and the like so as to be in a safe state.

1) Removal of the cooling material between the inner and outer tanks. The cold insulator 10 such as perlite filled between the outer tank side plate 3 and the inner tank side plate 7 and between the outer tank roof 4 and the inner tank roof 8 is scraped out from the manhole 11 such as the outer tank side plate 3 and removed. FIG. 1A).

2) Cutting around the inner tank roof. Cutting is performed at a portion inside the upper end of the inner tank side plate 7 around the inner tank roof 8.

The weight of the inner tank roof 8 obtained by cutting the periphery of the inner tank roof 8 is supported by the outer tank side plate 3 and the like via the outer tank roof 4 by the suspension rod 9 attached to the outer tank roof 4 to ensure safety. There is no above problem (see FIG. 1B).

3) Preparation of pneumatic support for the inner and outer tank roofs. The inner tank side plate 7 is provided around the inner tank roof 8 which is cut as necessary.
Air seal 12 such as cloth to prevent air leakage between
Install. Thereafter, the circumferential cut portion 13 of the outer tank roof 4 is formed.
The connecting jig 14 is attached to the outside of the outer tank roof 4 so as to straddle. The cutting portion 13 of the outer tank roof 4 at this time has a circumference large enough to be able to be lowered into the inner tank side plate 7 which is almost the same as the cutting position of the inner tank roof 8 (see FIG. 1 (c)). .

4) Pressing air into the inner tank and cutting the outer tank roof. Pressurized air is introduced into the inner tank in which the blower 15 is connected to the manhole of the inner tank side plate 7 so that the weight of the inner tank roof 8 and the outer tank roof 4 can be supported by air pressure. Thereafter, the cutting portion 13 around the outer tank roof 4 is cut. By cutting the outer tub roof 4, the weight of the inner tub roof 8 and the outer tub roof 4 is supported by the pressurized air introduced into the inner tub and supported by the connecting jig 14. (See FIG. 2 (a)).

5) Lowering of inner and outer tank roofs. After confirming the safety by adjusting the balance so that the inner tank roof 8 and the outer tank roof 4 connected by the hanging rod 9 can be supported by air pressure, the connecting jig 14 is removed and introduced into the inner tank. By controlling the amount of air while maintaining the balanced state by maintaining the pressure of the pressurized air, the inner and outer tank roofs 4, 8
Is lowered in an integrated state (see FIG. 2B).

6) Dismantling of the inner and outer tank roofs on the inner tank bottom plate and dismantling of the inner and outer tank side plates. After lowering the inner and outer tank roofs 4 and 8 onto the inner tank bottom plate 6 in this way, a large construction opening 16 is formed in the inner and outer tank side plates 3 and 7 to perform cutting and dismantling on the ground and use a crane 18 or the like. To cut and disassemble the inner tank side plate 7 and the outer tank side plate 3,
Further, after the inner tank bottom plate 6 is cut and dismantled, the bottom cold insulator 5
And finally the outer tank bottom plate 2 is cut and dismantled (Fig. 2
(C)).

By disassembling the double-shell low-temperature storage tank in this manner, the inner and outer tank roofs 4 and 8 can be dismantled on the ground, so that work at heights can be reduced by that much, and the inner and outer tank side plates 3 can be reduced. , 7 can be dismantled only with a crane or the like without temporarily installing a large-scale work scaffold, and there is no need for a work scaffold.

Further, compared with the conventional disassembly method, there is no need to temporarily work or remove the work scaffolding, so that the construction period can be greatly reduced.

[0023]

According to the method for dismantling a ground-type cylindrical tank according to the first aspect of the present invention, as described above in detail with one embodiment, after removing the cooling material between the inner and outer tanks, After cutting the periphery of the tank roof and supporting it with the outer tank roof, straddling the cut around the outer tank roof and attaching the jig for connection so that it can be supported even when cut, then pressurized air is blown to the inner tank In order to support the inner and outer tank roof by air pressure, the jig for connection was removed in this state, and the inner and outer tank roof was lowered to the ground while being supported by air pressure and dismantled. The tank roof can be dismantled, and it can be dismantled safely without the need for large-scale work scaffolds, reducing work in high places.

According to the method of disassembling the above-mentioned cylindrical tank according to the second aspect of the present invention, an air seal is attached around the roof of the inner tank to seal the air around the inner tank, so that it is supported by air pressure. Can be handled more reliably, and the descent can be performed safely.

[Brief description of the drawings]

FIG. 1 is a first half process diagram according to an embodiment in which a method of dismantling a ground-type cylindrical tank according to the present invention is applied to a double-shell low-temperature storage tank.

FIG. 2 is a second half process diagram according to an embodiment in which the above-described method of dismantling the above-ground cylindrical tank is applied to a double-shell low-temperature storage tank. .

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 foundation 2 outer tank bottom plate 3 outer tank side plate 4 outer tank roof 5 bottom cold insulator 6 inner tank bottom plate 7 inner tank side plate 8 inner tank roof 9 hanging rod 10 cold insulator 11 manhole 12 air seal 13 cutting part 14 connecting jig 15 blower 16 Construction opening 17 Crane

Claims (2)

[Claims] When disassembling the above-ground double-shell cylindrical tank, after removing the cooling material between the inner and outer tanks, the periphery of the inner tank roof is cut and supported by the outer tank roof. Attaching the connecting jig over the surrounding cut part, then introducing pressurized air into the inner tank to enable the inner and outer tank roof to be supported, then cutting the cut part around the outer tank roof, A method of dismantling a ground-type cylindrical tank, comprising removing the connecting jig, lowering the jig while supporting it with air pressure, and cutting and disassembling the inner and outer tank roofs and the inner and outer tank side walls. 2. An air seal for cutting the periphery of the inner tank roof and supporting the inner tank roof with an outer tank roof, and then sealing the space between the inner tank roof and a side wall of the inner tank. A method for dismantling a ground-type cylindrical tank according to item 1.