JPH08261397A - Gas purge device for low temperature liquefied gas storage tank - Google Patents

Abstract

PURPOSE: To reliably and high-efficiently purge gas remaining in a bottom cold insulation layer. CONSTITUTION: A purge piping 9 through which purge gas 8, such as nitrogen gas, is delivered is disposed in a bottom cold insulation layer 5 on the upper side of which an inner tank 2 in an outer tank 1 is arranged, and a piping 10 for discharging gas through which gas remaining in the bottom cold insulation layer 5 and the purge gas 8 delivered through the purge piping 9 are sucked and discharged to the outside is disposed at the outer peripheral part of the bottom cold insulation layer 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas purging device for a low temperature liquefied gas storage tank.

[0002]

2. Description of the Related Art FIG. 15 shows an example of a low-temperature liquefied gas storage tank for storing a low-temperature liquefied gas such as LNG, where 1 is an outer tank and 2 is a low-temperature liquefied gas arranged in an outer tank 1. The inner tank 3 for storing gas is a suspended ceiling suspended from the inner surface of the roof of the outer tank 1, and the inner tank 2 is a concrete block 4 annularly arranged at the bottom of the outer tank 1, It is arranged so as to be placed on the bottom cold insulation layer 5 arranged in the concrete block 4.

As shown in FIG. 16, the bottom cold insulation layer 5 is spread in the concrete block 4 by using a large number of cold insulation material blocks 5a such as foam glass and stacked in a plurality of steps, and an aluminum foil is provided between each step. The capping material 5b in the shape is interposed.

In the figure, 6 is a level adjusting material made of concrete provided below the concrete block 4 and the bottom cold insulation layer 5, and 7 is interposed between the bottom cold insulation layer 5 and the bottom surface of the inner tank 2. It is a dry sand.

The low temperature liquefied gas storage tank as described above is inspected once every ten years or so. At the time of the open inspection, after the low temperature liquefied gas stored in the inner tank 2 is extracted, A purge gas such as nitrogen gas is supplied into the outer tank 1 and the inner tank 2 to purge methane gas and the like, and after the purging work is completed, a worker enters the outer tank 1 and the inner tank 2 to perform various inspection works. Has become.

[0006]

However, in the case of the low temperature liquefied gas storage tank as described above, since a large number of air bubbles are present in the cold insulating material block 5a such as foam glass forming the bottom cold insulating layer 5, Methane gas or the like has entered and remained inside the cold insulating material block 5a, and by simply supplying a purge gas such as nitrogen gas into the outer tank 1 and the inner tank 2, the methane gas or the like remaining inside the cold insulating material block 5a can be obtained. Had the drawback that it was difficult to drive it out completely.

In view of the above situation, the present invention is to provide a gas purging device for a low temperature liquefied gas storage tank which can reliably and efficiently purge the gas remaining inside the bottom cold insulating layer.

[0008]

A first aspect of the present invention relates to a low temperature liquefied gas storage tank in which an inner tank for storing low temperature liquefied gas is arranged on a bottom cold insulating layer formed on the inner bottom of the outer tank. A gas purging device, in which a purge pipe for sending a purge gas is provided in the bottom cold insulation layer, and the gas remaining in the bottom cold insulation layer and the purge gas sent from the purge pipe are sucked into the outer periphery of the bottom cold insulation layer. It is characterized in that a pipe for discharging gas to be discharged to is disposed.

A second aspect of the present invention is a gas purging device for a low temperature liquefied gas storage tank in which an inner tank for storing a low temperature liquefied gas is arranged on a bottom cold insulation layer formed on the inner bottom of the outer tank. A purge pipe for sending a purge gas is provided around the outer periphery of the bottom cold insulation layer, and the gas remaining in the bottom cold insulation layer and the purge gas sent from the purge pipe are sucked into the bottom cold insulation layer and discharged to the outside. It is characterized in that a discharge pipe is provided.

Furthermore, a third aspect of the present invention is a gas purging device for a low temperature liquefied gas storage tank, wherein an inner tank for storing low temperature liquefied gas is arranged on a bottom cold insulating layer formed on the inner bottom of the outer tank. Therefore, in the bottom cool layer, a purge pipe for sending the purge gas, and a gas discharge auxiliary pipe for sucking the gas remaining in the bottom cool layer and the purge gas sent from the purge pipe and discharging it to the outside are provided. A gas discharge pipe for sucking in the gas remaining in the bottom cold insulating layer and the purge gas sent from the purge pipe and discharging the gas to the outside is arranged on the outer periphery of the bottom cold insulating layer.

[0011]

Therefore, in the first aspect of the present invention, at the time of the open inspection of the low temperature liquefied gas storage tank, after the low temperature liquefied gas stored in the inner tank is extracted, the purge gas is sent from the purge pipe into the bottom cold insulation layer, Methane gas and the like that have entered and remained inside the bottom cold insulating layer are reliably expelled by the purge gas, sucked together with the purge gas from the gas discharge pipe, and discharged to the outside. Workers can enter the tank and perform various inspections.

Further, in the second aspect of the invention, at the time of open inspection of the low temperature liquefied gas storage tank, after the low temperature liquefied gas stored in the inner tank is extracted, the purge gas is sent from the purge pipe to the outer periphery of the bottom cold insulating layer. Since the methane gas etc. that has entered and remained inside the bottom cold insulation layer is sucked into the gas discharge pipe and is purged by the purge gas from the purge pipe, after this, the worker is placed inside the outer tank and the inner tank. It becomes possible to perform various inspection work by entering.

Furthermore, in the third aspect of the present invention, at the time of open inspection of the low temperature liquefied gas storage tank, the low temperature liquefied gas stored in the inner tank is extracted, and then the purge gas is sent from the purge pipe into the bottom cold insulation layer. The methane gas and the like remaining inside the bottom cold insulating layer are surely expelled by the purge gas, sucked together with the purge gas from the gas discharge auxiliary pipe, and also sucked from the gas discharge pipe. After that, the worker can enter the outer tank and the inner tank to perform various inspection work.

[0014]

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

1 to 6 show a first embodiment of the present invention. In the drawings, the parts designated by the same reference numerals as those in FIGS. 15 and 16 represent the same parts, and the basic structure is as shown in FIG. 15 and 16 are similar to the conventional ones, but the feature of this embodiment is that the bottom cold insulation layer 5 is formed as shown in FIGS.
A purge pipe 9 for feeding a purge gas 8 such as nitrogen gas is provided inside, and a gas (methane gas or the like) remaining in the bottom cold keeping layer 5 and the purge pipe 9 are fed to the outer periphery of the bottom cold keeping layer 5. The point is that a gas discharge pipe 10 for sucking the purge gas 8 and discharging it to the outside is provided.

As shown in FIG. 1, the purge pipe 9 is connected at its base end side to a purge gas cylinder 11 arranged outside the outer tank 1 via a supply pump 12 and penetrates the roof of the outer tank 1. 2, a purge pipe 9 that hangs down between the outer tub 1 and the inner tub 2, extends through the concrete block 4 into the bottom cold insulation layer 5, and extends into the bottom cold insulation layer 5. Is a space 13 formed between the cold insulating material blocks 5a of each stage, which are partitioned by the capping material 5b of the bottom cold insulating layer 5.
(See FIG. 4), and the tip side thereof is bifurcated at the central portion of the bottom cold insulating layer 5, as shown in FIG.
As shown in FIG. 4, blow-out holes 14 for the purge gas 8 are formed in the circumferential direction at a required pitch in the arc-shaped portion, the tip of which is closed by the blind flange 16, as shown in FIG. In the space 13 formed between the material blocks 5a, the cold insulating material 1 such as glass wool is covered so as to cover the purge pipe 9.
5 is filled. A loop portion 9a for absorbing heat shrinkage is formed at a required lower portion of the hanging portion of the purge pipe 9 between the outer tank 1 and the inner tank 2, and as shown in FIG. If the purge pipes 9 are arranged at exactly the same position for each stage of the material block 5a, the strength of the bottom cold insulation layer 5 at that portion is reduced. To avoid this,
The purge pipe 9 extending in the radial direction of the bottom cold insulating layer 5 is displaced at least in each stage, and the diameter of the arc-shaped portion of the purge pipe 9 is changed in each stage of the cold insulating material block 5a.

Further, as shown in FIG. 3, the gas discharge pipe 10 is closed at its ends with blind flanges 17 in the space between the outer tank 1 and the inner tank 2 in the outer periphery of the bottom cold insulation layer 5. The intake pipes 10a having two semicircular arcs are arranged, and the intake pipes 10a are fixed on a plurality of support brackets 18 fixed to required positions on the bottom surface of the outer tub 1, as shown in FIGS. 5 and 6. The suction pipes 10 are fixed by U bolts 19
A suction hole 20 for sucking in the gas (methane gas or the like) remaining in the bottom cold insulation layer 5 and the purge gas 8 fed from the purge pipe 9 is formed at a predetermined pitch in the circumferential direction on the inner peripheral surface side of a. , The communication pipe 10b is set up from the middle portion of each suction pipe 10a, as shown in FIGS.
It has a configuration in which the roof of the outer tub 1 is penetrated and is connected to a vacuum pump 21 arranged outside the outer tub 1. When the space between the outer tank 1 and the inner tank 2 is filled with a cold insulating material such as granular perlite, it is prevented that the cold insulating material such as granular perlite is sucked into the gas discharge pipe 10. In order to do so, a net (not shown) is attached to the suction hole 20.

Next, the operation of the above embodiment will be described.

At the time of open inspection of the low temperature liquefied gas storage tank, the low temperature liquefied gas stored in the inner tank 2 is extracted, and then the purge gas 8 such as nitrogen gas in the purge gas cylinder 11 is driven by the supply pump 12 to drive the purge pipe 9 When the vacuum pump 21 is driven while being fed into the bottom cold insulation layer 5 from the above, the methane gas etc. remaining inside the large number of bubbles existing in the cold insulation block 5a such as foam glass forming the bottom cold insulation layer 5 is It is reliably expelled by the purge gas 8, is sucked together with the purge gas 8 from the suction pipe 10a of the gas discharge pipe 10, and is connected to the communication pipe 10b.
Since it is discharged to the outside after passing through, the worker can enter the inside of the outer tub 1 and the inner tub 2 to perform various inspection work.

In this way, the gas remaining inside the bottom cold insulating layer 5 can be reliably and efficiently purged.

7 to 11 show a second embodiment of the present invention. In the drawings, the parts designated by the same reference numerals as those in FIGS. 1 to 6 represent the same things. The gas discharge pipe 10 in the first embodiment shown is used as a purge pipe 10 'for feeding the purge gas 8 to the outer periphery of the bottom cold insulation layer 5, and the purge pipe 9 in the first embodiment is used in the bottom cold insulation layer 5. The residual gas and the purge gas 8 fed from the purge pipe 10 'are used as a gas discharge pipe 9'for sucking and discharging the gas to the outside. Therefore, the purge pump 10' is connected to the purge pump 10 '. A purge gas cylinder 11 is connected to the gas discharge pipe 9'through a vacuum pump 21.

In FIG. 10, 14 'is a suction hole formed in the gas discharge pipe 9', and 20 'in FIG. 11 is an outlet hole formed in the purge pipe 10'.

In the second embodiment shown in FIGS. 7 to 11, the inner tank 2 is used at the time of open inspection of the low temperature liquefied gas storage tank.
After the low temperature liquefied gas stored inside is extracted, the purge gas 8 such as nitrogen gas in the purge gas cylinder 11 is sent from the purge pipe 10 ′ to the outer periphery of the bottom cold insulating layer 5 by driving the supply pump 12, and the vacuum pump 21 is turned on. When driven, methane gas or the like that has entered and remains inside a large number of bubbles existing in the cold insulating material block 5a such as foam glass that constitutes the bottom cold insulating layer 5 is sucked into the gas discharge pipe 9 ', and the purge pipe is also used. Since the purge gas 8 from 10 ′ is used for the purging, after that, a worker can enter the inside of the outer tank 1 and the inner tank 2 to perform various inspection work.

Thus, also in the case of the second embodiment shown in FIGS. 7 to 11, the gas remaining inside the bottom cold insulating layer 5 can be reliably and efficiently purged.

12 to 14 show a third embodiment of the present invention. In the drawings, the parts denoted by the same reference numerals as those in FIGS. 1 to 6 represent the same things, and the tip of the purge pipe 9 is It extends to a required radial position in the bottom cold insulation layer 5 without being divided into two parts, and a gas discharge filter 22 made of a porous material is attached to the tip of the purge pipe 9 so as to be substantially symmetrical with the purge pipe 9. In the bottom cold insulation layer 5, the filter 2
A gas discharge auxiliary pipe 24 having a gas suction filter 23 similar to that of No. 2 attached to the tip thereof is disposed, and the base end side of the gas discharge auxiliary pipe 24 is connected to the concrete block 4 as shown in FIG. It is made to pass through and stand up, and as shown in FIG. 12, the roof of the outer tub 1 is pierced and connected to a vacuum pump 21 arranged outside the outer tub 1.

In the third embodiment shown in FIGS. 12 to 14, the inner tank 2 is used at the time of open inspection of the low temperature liquefied gas storage tank.
After the low-temperature liquefied gas stored therein is extracted, the purge gas 8 such as nitrogen gas in the purge gas cylinder 11 is driven by the supply pump 12 through the purge pipe 9 from the filter 22 at the tip into the bottom cold insulation layer 5, and When the vacuum pump 21 is driven, the methane gas and the like remaining inside the large number of bubbles existing in the cold insulating material block 5a such as the foam glass forming the bottom cold insulating layer 5 are surely expelled by the purge gas 8, and The purge gas 8
Along with this, it is sucked from the filter 23 of the gas discharge auxiliary pipe 24 and also sucked from the suction pipe 10a of the gas discharge pipe 10 and discharged to the outside, and thereafter, inside the outer tank 1 and the inner tank 2. Workers can enter and perform various inspection work.

Thus, also in the case of the third embodiment shown in FIGS. 12 to 14, the gas remaining inside the bottom cold insulating layer 5 can be surely and efficiently purged.

The gas purging device for a low temperature liquefied gas storage tank according to the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the present invention. is there.

[0029]

As described above, the first aspect of the present invention is as described above.
According to the gas purging device for a low-temperature liquefied gas storage tank described in any one of 3 to 3, the excellent effect that the gas remaining inside the bottom cold insulating layer can be surely and efficiently purged can be obtained.

[Brief description of drawings]

FIG. 1 is an overall side sectional view of a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a II part in FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

4 is a sectional view taken along the line IV-IV in FIG.

5 is a sectional view taken along line VV of FIG.

6 is a VI-VI arrow view of FIG.

FIG. 7 is an overall side sectional view of a second embodiment of the present invention.

8 is an enlarged cross-sectional view of a VIII portion of FIG.

9 is a sectional view taken along line IX-IX in FIG.

10 is a sectional view taken along line XX of FIG.

11 is a sectional view taken along line XI-XI of FIG.

FIG. 12 is an overall side sectional view of a third embodiment of the present invention.

FIG. 13 is an enlarged cross-sectional view of a XIII portion of FIG.

14 is a sectional view taken along line XIV-XIV in FIG.

FIG. 15 is an overall side sectional view of a conventional example.

16 is an enlarged cross-sectional view of the XVI portion of FIG.

[Explanation of symbols]

 1 Outer tank 2 Inner tank 5 Bottom cold insulation layer 8 Purge gas 9 Purge pipe 9'Gas discharge pipe 10 Gas discharge pipe 10 'Purge pipe 24 Gas discharge auxiliary pipe

Claims (3)

[Claims] 1. A gas purging device for a low-temperature liquefied gas storage tank, comprising an inner tank for storing low-temperature liquefied gas, which is arranged on a bottom cold-insulating layer formed on the bottom of the outer cold-insulating layer. And a purge pipe for feeding the purge gas, and a gas discharge pipe for sucking in the gas remaining in the bottom cold insulation layer and the purge gas fed from the purge pipe and discharging the same to the outer periphery of the bottom cold insulation layer. A gas purging device for a low-temperature liquefied gas storage tank, characterized in that 2. A low-temperature liquefied gas storage tank gas purging device comprising an inner tank for storing low-temperature liquefied gas, which is disposed on a bottom cold-insulating layer formed on the bottom of the outer cold-insulating layer. Part, a purge pipe for sending a purge gas is provided, and a gas exhaust pipe for sucking in the gas remaining in the bottom cool layer and the purge gas sent from the purge pipe and discharging it to the outside is provided in the bottom cool layer. A gas purging device for a low-temperature liquefied gas storage tank, characterized in that 3. A gas purging device for a low temperature liquefied gas storage tank comprising an inner tank for storing a low temperature liquefied gas arranged on a bottom cold insulation layer formed on the bottom of the outer cold storage layer, wherein And the purge pipe that sends the purge gas,
A gas discharge auxiliary pipe for sucking in the gas remaining in the bottom cold insulation layer and the purge gas sent from the purge pipe and discharging it to the outside is provided, and at the outer periphery of the bottom cold insulation layer, the gas remaining in the bottom cold insulation layer Also, a gas purging device for a low-temperature liquefied gas storage tank is provided, which is provided with a gas discharge pipe for sucking in the purge gas sent from the purge pipe and discharging it to the outside.