JPH10101191A - Low temperature tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively realize a low temp. tank capable of preventing the leakage of low temp. liquefied gas to the outside of an outer tank when an inner tank is damaged by an earthquake or the like by construction due to easy execution control. SOLUTION: In a low temp. tank 19 having a double shell structure consisting of an inner tank 2 and the outer tank 3 surrounding the inner tank 2, the side plate 4 and bottom plate 5 of the outer tank are constituted of the same material for low temp. as the inner tank 2 and a bottom part cold heat-resistant relaxing material 20 having heat insulating properties is liquidtlghtly laid on the upper surface of the bottom plate 5 of the outer tank and the inner tank 2 is arranged on this bottom part cold heat-resistant relaxing material 20 and the outer tank 3 and the inner tank 2 are respectively connected so as to be capable of permitting relative displacement at a time of low temp. shrinkage to the foundation 6 and the side plate 4 of the outer tank is made possible to function as a liquid preventing bank without hindrance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-shell cryogenic tank comprising an inner tank and an outer tank.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a low-temperature tank 1 for storing a low-temperature liquefied gas 12 such as LNG, LPG, etc. This kind of low-temperature tank 1 has an inner tank 2 and an outer tank surrounding the inner tank 2. It has a double shell structure composed of a tank 3, and a space between the inner tank 2 and the outer tank 3 is filled with a cooling material such as pearlite so as to provide heat insulation inside and outside the tank.

The outer tub 3 has a cylindrical outer tub side plate 4 forming a body portion, the lower surface of which is closed by an outer tub bottom plate 5 to form a foundation 6.
The inner tub 2 has a structure in which the upper surface of the outer tub side plate 4 is closed by a dome-shaped outer tub roof 7, and the inner tub 2 has a cylindrical inner tub side plate 8 forming a body portion. The lower surface is closed by the inner tank bottom plate 9, installed on the outer tank bottom plate 5 via the bottom insulating layer 10, and the upper surface of the inner tank side plate 8 is closed by a dome-shaped inner tank roof 11. The inner tank side plate 8, inner tank bottom plate 9, and inner tank roof 11, which come into direct contact with the low-temperature liquefied gas 12, are made of a low-temperature material having a low embrittlement transition temperature. The tank side plate 4, the outer tank bottom plate 5, and the outer tank roof 7 are made of a normal room temperature material.

[0004] As shown in FIG. 4, the connection of the inner tank 2 to the base 6 is performed by a plurality of flexible members so as to allow relative displacement of the inner tank 2 to the base 6, which contracts at a low temperature due to the storage of the low-temperature liquefied gas 12. The anchor strap 13 has a lower end fixed to the bottom of an anchor strap box 14 embedded in the foundation 6, extends vertically, and has an upper end in the lower portion of the inner tank side plate 8. Each is fixed at a plurality of positions in the circumferential direction.

On the other hand, the connection of the outer tub 3 to the foundation 6 is usually provided at a plurality of circumferential locations on the lower portion of the outer tub side plate 4 because it is not necessary to consider the low temperature shrinkage of the outer tub 3. This is performed by fastening and fixing with a nut 17 to the perforated bracket 15 through an anchor bolt 16 implanted in the foundation 6.

In the low temperature tank 1 configured as described above, when a large earthquake occurs, a large inertial force acts on the inner tank 2 storing the low temperature liquefied gas 12 therein. Even if the outer tub 3 has sufficient strength to withstand seismic force, the inner tub 2 may be damaged and the low-temperature liquefied gas 12 may leak.

If the low-temperature liquefied gas 12 leaks from the inner tank 2, the outer tank side plate 4 and the outer tank bottom plate 5, which are made of a material for normal temperature, are rapidly cooled and are damaged by low-temperature embrittlement, or The stress caused by the sudden low-temperature shrinkage of the outer tank bottom plate 5 concentrates on the portion fixed and fastened to the foundation 6 through the perforated bracket 15 by the anchor bolts 16 and the nuts 17 and breaks down to the outside of the outer tank 3. The low temperature liquefied gas 12 may leak.

For this reason, in general, in order to prevent secondary disasters such as pollution of the surrounding environment, the surroundings of the low-temperature tank 1 may be surrounded by a dike 18 (see FIG. 3) at a distance,
Alternatively, as shown in FIG. 5, a liquid barrier 18 'made of PC (prestressed concrete) is attached to the outer tank side plate 4 of the low-temperature tank 1.
Was arranged as close as possible.

[0009]

However, when the periphery of the low-temperature tank 1 is surrounded by the dike 18 at a distance as in the former case, the area of the site occupied by the dike 18 is reduced. It becomes wide, land cost and dike 18
There was a problem that the cost of safety measures in the house would rise.

On the other hand, as in the latter, a PC-made dike 1
If 8 'is arranged as close as possible to the outer tank side plate 4 of the low-temperature tank 1, the construction cost of the PC-made liquid barrier 18' itself is high, and civil and mechanical work is required at the time of construction. However, there is a problem that construction management is difficult because of complicated operations.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and provides an inexpensive and easy-to-use low-temperature tank that can prevent low-temperature liquefied gas from leaking to the outside of the outer tank when the inner tank is damaged due to an earthquake or the like. It is intended to be realized by construction by construction management.

[0012]

SUMMARY OF THE INVENTION The present invention is directed to a low temperature tank having a double shell structure comprising an inner tank and an outer tank surrounding the inner tank, wherein the outer tank side plate and the outer tank bottom plate have the same low temperature as the inner tank. A heat insulating material having a heat insulating property on the bottom surface of the outer tank bottom plate in a liquid-tight manner, and installing an inner tank on the lower heat resistance reducing material, and each of the outer tank and the inner tank. Are connected to the base so as to allow relative displacement during shrinkage at low temperature.

Therefore, according to the present invention, even if the low-temperature liquefied gas leaks out of the low-temperature tank when the inner tank is damaged by an earthquake or the like,
Since the outer tub side plate and the outer tub bottom plate are made of a material for low temperature, the outer tub side plate and the outer tub bottom plate are not damaged by low-temperature embrittlement, and the outer tub bottom plate has a heat insulating bottom heat resistance. Since the outer tank side plate is in direct contact with the low-temperature liquefied gas and is prevented from rapidly shrinking at a low temperature, the relative displacement between the outer tank bottom plate and the base is reduced, Moreover, since the outer tank is connected to the foundation so as to allow relative displacement with respect to the foundation at the time of low-temperature shrinkage similarly to the inner tank side, breakage due to stress concentration due to low-temperature shrinkage of the outer tank bottom plate does not occur.

This makes it possible for the outer tank side plate to function as a liquid barrier without hindrance, and to keep the low-temperature liquefied gas leaked from the inner tank in the outer tank to prevent the low-temperature tank from leaking outside. It becomes possible.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show an example of an embodiment of the present invention, in which the same reference numerals as in FIG. 3 denote the same parts.

In the low temperature tank 19 having a double shell structure substantially similar to the low temperature tank 1 of FIG. 3 described above, the outer tank side plate 4 and the outer tank bottom plate 5 are connected to the low temperature tank having the same low embrittlement transition temperature as the inner tank 2. A lower heat resistance reducing material 20 having heat insulating properties is laid in a liquid-tight manner on the upper surface of the outer tank bottom plate 5, and the inner bath 2 is placed on the lower cooling heat resistance reducing material 20 via the bottom cold insulating layer 10. Install.

Here, for example, perlite concrete or the like may be used as the bottom thermal resistance reducing material 20, and a coating such as glass cloth may be applied to the upper surface in order to impart liquid tightness.

The connection of the inner tub 2 to the foundation 6 is performed by using an anchor strap 13 in the same manner as in the prior art. However, the outer tub 3 conventionally fixed by anchor bolts is also connected to the inner tub 2. Similarly to the above, the anchor 6 is connected to the foundation 6 using a plurality of anchor straps 21 so that relative displacement with respect to the foundation 6 at the time of low-temperature shrinkage can be allowed.

That is, the anchor strap 21 connecting the outer tub 3 to the base 6 extends vertically with the lower end fixed to the bottom of an anchor strap box 22 embedded in the base 6 and the upper end is connected to the outer tub side plate. 4 are respectively fixed at a plurality of locations in the circumferential direction in the lower portion.

Therefore, even if the low-temperature liquefied gas 12 leaks out of the low-temperature tank 19 when the inner tank 2 is damaged due to an earthquake or the like,
Since the outer tank side plate 4 and the outer tank bottom plate 5 are made of a material for low temperature, the outer tank side plate 4 and the outer tank bottom plate 5 are not damaged by low-temperature embrittlement. , The outer tank side plate 4 is prevented from being in direct contact with the low-temperature liquefied gas 12 and rapidly shrinking at a low temperature, so that the outer tank bottom plate 5 and the foundation 6 can be prevented. And the outer tub 3 is connected to the foundation 6 using the anchor straps 21 similarly to the inner tub 2 so as to allow relative displacement during low-temperature contraction. Breakage due to stress concentration due to low-temperature shrinkage of the outer tank bottom plate 5 does not occur.

This makes it possible for the outer tank side plate 4 to function as a liquid barrier 18 without hindrance. The low-temperature liquefied gas 12 leaked from the inner tank 2 is retained in the outer tank 3 and is transferred to the outside of the low-temperature tank 19. Leakage can be prevented.

The low-temperature liquefied gas 12 leaked from the inner tank 2
After leaving the inside of the outer tank 3, the low-temperature liquefied gas 12 may be extracted by a liquid discharging pump (not shown) provided in the inner tank 2.
Since the liquid level between the inner tank 2 and the outer tank 3 decreases in accordance with the decrease in the liquid level in the inner tank 2, the low-temperature tank 19 can be emptied.

The vaporized gas filled in the low-temperature tank 19 is discharged to the atmosphere from a gas discharge line (not shown) provided on the inner tank roof 11 and the outer tank roof 7 via a safety valve. Good.

Therefore, according to the above embodiment, the low-temperature tank 1
By making the outer tank side plate 4 which is one of the components 9 function as the liquid barrier 18, it is possible to prevent the low-temperature liquefied gas 12 from leaking out of the outer tank 3 when the inner tank 2 is damaged due to an earthquake or the like. The problem that the land area occupied by the dike increases and the cost of land and safety measures inside the dike rises, as in the case of surrounding the cryogenic tank with a dike at a distance. In addition, the construction cost can be reduced compared with the case where the PC-made liquid barrier is placed as close as possible to the outer tank side plate of the low-temperature tank, and the civil engineering work and the mechanical work are complicated at the time of construction. The construction management becomes easy.

Incidentally, the low-temperature tank of the present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the gist of the present invention.

[0027]

According to the low temperature tank of the present invention described above,
By making the outer tank side plate, which is one component of the low-temperature tank, a barrier, the low-temperature liquefied gas can be prevented from leaking out of the outer tank when the inner tank is damaged due to an earthquake or the like. As a result, the land area occupied by the dike increases and the cost of safety measures inside the dike increases, as in the case where the dike is surrounded at a distance by the dike. Moreover, P
The construction cost is lower than in the case where the C dike is placed as close as possible to the outer tank side plate of the low-temperature tank. In addition, there is no trouble that civil engineering and mechanical work are complicated at the time of construction, and construction management is reduced. Various excellent effects, such as ease, can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of an embodiment of the present invention.

FIG. 2 is an enlarged view showing details of a portion II in FIG. 1;

FIG. 3 is a sectional view showing a conventional example.

FIG. 4 is an enlarged view showing details of an IV section in FIG. 3;

FIG. 5 is a sectional view showing another conventional example.

[Explanation of symbols]

 2 Inner tank 3 Outer tank 4 Outer tank side plate 5 Outer tank bottom plate 6 Foundation 19 Low-temperature tank 20 Bottom cold resistance

Claims (1)

[Claims] 1. A low temperature tank having a double shell structure comprising an inner tank and an outer tank surrounding the inner tank, wherein an outer tank side plate and an outer tank bottom plate are made of the same low temperature material as the inner tank. A bottom heat-resistance reducing material having heat insulating properties is laid down in a liquid-tight manner on the upper surface of the tank bottom plate, and an inner tank is installed on the bottom heat-resistance reducing material. A low-temperature tank, which is connected to allow relative displacement.