JPS6228356B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> This invention is applicable to on-site construction when filling cold insulation material between the inner and outer tanks after constructing the inner and outer tanks of a double-shell cryogenic tank for storing low-temperature liquids such as LNG. This invention relates to a cold insulating material filling method in which the foamed cold insulating material obtained by firing the raw stone is filled by gas transport, and in particular, the foamed cold insulating material after firing the raw stone is filled with an inert gas such as _N2 . This invention relates to a method for filling a double-shell low-temperature tank with a cold insulator, in which gas is transported and filled, and air and inert gas between the inner and outer tanks are simultaneously replaced over time.

<Prior art> As is well known, so-called double-shell cryogenic tanks are used as storage tanks for low-temperature liquids such as LNG and other low-temperature liquefied gases. Since the temperature difference is extremely large, a cold insulating material is filled and interposed between the inner and outer tanks forming a double shell.

Various types of cold insulation materials are used, and various conditions such as filling means, filling rate, etc., construction efficiency, heat insulation, fire resistance, lightness, low low-temperature shrinkage, etc. Foamed cold insulation materials such as perlite are often used due to their superior properties.

When filling with foamed cold insulating materials such as perlite, an on-site foam filling method is usually used, taking into consideration cost, prevention of metamorphosis, and work efficiency. 1, the air is transported through a pipe through a gas transport device 2, and the space between the inner and outer tanks 6 and 7 of the double-shell low-temperature tank 3 is filled through a circular nozzle (not shown). is discharged from the manhole 4 through the filter 5 to the outside air.

<Problems to be Solved by the Invention> By the way, as a matter of course, air is interposed between the inner and outer tanks 6 and 7 after construction of the double-shell cryogenic tank 3, so that the temperature will remain low during operation. Because of this, there is a disadvantage that moisture in the intervening air may condense, so after filling the foam cold insulation material, inert gas such as N ₂ gas is sent between the inner and outer tanks 6 and 7 to expel the air. It is intended to be replaced.

However, conventionally, for example, the inner and outer tanks 6, 7
Since the N ₂ gas supply pipe 8 is installed at the bottom of the gap, there is a disadvantage that the cost is extremely high.
In addition, it is difficult to replace after filling with pearlite, etc., and when the outer surface of the inner tank is lined with glass wool, the _N2 gas bypasses and dissipates along the glass wool. .

The purpose of this invention is to solve the technical problem of replacing air with inert gas when filling the inner and outer walls of a low-temperature liquid storage tank with cold insulating material based on the above-mentioned conventional technology, and to solve the problem by firing raw stones on-site. By taking advantage of the advantages of foam filling and using an inert gas such as N ₂ gas instead of the conventional air transport for the gas transport used as a filling means, it is possible to perform transport means and air replacement at the same time, thereby improving the energy industry. The purpose of this invention is to provide an excellent method for filling a double-shell cryogenic tank with cold insulation material, which is useful for the field of tank technology application.

<Means and operations for solving the problems> In order to solve the above problems, the structure of the present invention, which is based on the above-mentioned claims, is based on the inner tank and the outer tank of the double-shell cryogenic tank. During this process, the rough stone is fired on-site to produce a foamed cold insulating material such as perlite, which is then transferred to a gas transportation device and transported by an inert gas such as N ₂ gas from an N ₂ gas supply device to form a double shell. The inert gas is delivered between the outer and outer tanks of a low-temperature tank, and in this process, the transported inert gas replaces the air existing between the inner and outer tanks, and some of the inert gas is discharged as a mixture with air. , gas is transported to the cold insulation material again, and in this way, the amount of air in the mixture discharged during the process of filling the cold insulation material by repeated gas transportation increases, so it is discharged to the outside air in the discharge process, By replenishing new inert gas and supplying it for gas transport, and repeating this process, a cold insulator is filled between the inner and outer tanks of the double-shelled cryogenic tank, and the inert gas is gradually replaced with air. Technical measures have been taken to ensure that the water is filled.

<Example> Next, an example of the present invention will be described below with reference to FIGS. 2 and 3. Note that the same parts as in FIG. 1 will be explained using the same reference numerals.

The embodiment shown in FIG. 2 shows the principle of the present invention, in which a predetermined raw stone is fired in a firing device 1, and pearlite, which is a foamed cold insulating material, is transferred to a gas transport device 2' to supply _N2 gas. _N2 gas from the device 9 is transported between the inner and outer tanks 6 and 7 of the double-shell cryogenic tank 3,
Perlite 10 is filled in a swirling manner, and the _N2 gas used for transportation in the filling process is supplied to the inner and outer tanks 6 and 7.
The replaced air is filled by replacing the air existing in between, and the replaced air transports the perlite 10 and is foamed with the air.It passes from the manhole 4 through the filter 5' together with the surplus _N2 gas that is mixed with the air. , the N ₂ gas is returned to the N 2 gas supply device 9, and this circulation is repeated. During this period, the pearlite floating in the N ₂ gas that is about to be recirculated is filtered by the filter 5' and remains in the double shell low temperature tank 3 and is not circulated. , at a given timing
The circulated portion of the N ₂ gas is released into the atmosphere by the N ₂ gas supply device 9, and new N ₂ gas is supplied as a carrier gas, so that the pearlite 10 is filled while replacing the air and N ₂ gas one by one. west,
When the filling of pearlite 10 is completed, N ₂ gas is filled between the inner and outer tanks 6 and 7.

In the embodiment shown in FIG. 3, reference numeral 11 denotes a stocker for raw pearlite, and the raw pearlite is cut out in fixed quantities by a vibrating feeder 12, fed to a hopper 14 of a firing device 1 by a belt conveyor 13, and fed to a feeder 15. The powder is then fired and foamed at a predetermined temperature by a burner 18 in a furnace 17 via a bucket conveyor 16 to become a cold insulating material raw material for pearlite 10, and is transferred to a cooling pipe 21 of a gas transport device 2' by a chute 19, where it is being cooled. The gas is supplied to the cyclone 22 of the gas transport device 2', and is supplied from the _N2 gas supply device 9.
A kind of gas transport was carried out through the mixing device 23 using N ₂ gas and a blower (not shown) by an appropriate means such as an injector, and the mixture was transported through the transport pipe 24 and inserted into the manhole 31 of the double-shell cryogenic tank 3. The space between the inner and outer tanks 6 and 7 of the double-shelled low-temperature tank 3 is filled from the flexible hose 25, and perlite 10 is sequentially filled in a predetermined process by the rotating motion of the flexible hose 25.

In the process of filling the pearlite 10, the transport _N2 gas is simultaneously supplied between the inner and outer tanks 6 and 7, and is stirred and replaced to expel the pre-existing air. interposed between.

Then, _N2 gas is filled between the inner and outer tanks 6 and 7 together with perlite 10, but some of the supplied gas is
The N ₂ gas is stirred and mixed with air and subjected to a disturbance action, and at that time, it is sucked together with some of the floating particles of pearlite 10 from the duct 4 to the blower (not shown) of the N ₂ gas supply device 9 via the return pipe 26. and is discharged from the double-shell cryogenic tank 3.

However, due to the presence of the filter 5' provided in the duct 4 of the double-shell low-temperature tank 3, the particles of perlite 10 that are sucked in are not discharged, and only the mixture of air and _N2 gas is discharged and passes through the return pipe 26. , is returned to the N ₂ gas supply device 9.

The air and N ₂ gas mixture returned to the N ₂ gas supply device 9 passes through an appropriate filter (not shown), reaches the injector via the blower again, sucks out the perlite 10, and supplies and fills the tank 3 by transporting the gas. By repeating recirculation and repeating this process, air and air are filled while filling with perlite 10.
Perform _N2 gas replacement.

Therefore, returning through the replacement process
Since the amount of air occupied in the mixture of N ₂ gas and air gradually increases, a valve (not shown) installed in the return path in the N ₂ gas supply device 9 is switched appropriately to supply air to the atmosphere through the duct 12'. At the same time, new N ₂ gas is supplied and the same perlite 10 is charged.

In this way, by repeating the filling of pearlite 10 with a new supply of N ₂ gas and the intermittent release of part of the circulating gas to the atmosphere, pearlite 10 is continuously supplied and filled, and air and N ₂ gas are also gradually added. The amount of N ₂ gas used is limited and saved as much as possible.

When the predetermined amount of pearlite 10 is filled, the pearlite 10 is filled into the injector.
By stopping the supply of N ₂ gas and repeating supply circulation with only N 2 gas or circulation supply with atmospheric release for a specified period of time, residual air and unsubstituted air are completely purged, and finally N ₂ gas Perform replacement filling.

It should be noted that the embodiments of the present invention are of course not limited to the above-mentioned embodiments, and for example, the inert gas is not limited to N ₂ gas, and other gases can also be used.

<Effects of the Invention> As described above, according to the present invention, in the method of gas transporting and filling the foamed cold insulating material by on-site firing between the inner and outer tanks of a double-shelled low-temperature tank, it is possible to replace the conventional pneumatic transport.
By using inert gas such as _N2 gas in the transportation means, in addition to the basic advantages of filling foam cold insulation materials on-site, it is possible to omit the step of replacing the air with inert gas after filling the foam material. , the filling of a cold insulating material such as perlite and the replacement of air with an inert gas can be carried out in one step, and therefore the construction period is significantly shortened and the cost is also reduced.

In addition, by using inert gas as a transportation means for filling the cold insulation material and replacing it with air, it is possible to eliminate the gap between the inner and outer tanks of a double-shelled low-temperature tank as in the past. There is no need for piping equipment for charging active gas, which also has the excellent effect of reducing man-hours and lowering costs.

Furthermore, since the inert gas can unavoidably perform a kind of stirring action when filling the pearlite, it has the effect of eliminating the bypass phenomenon of air and inert gas and ensuring complete replacement.

Furthermore, since the mixture of inert gas and air is circulated, the inert gas used can be used as completely as possible, and from this point of view, there is an advantage that construction can be carried out at low cost.

Therefore, when filling the space between the inner and outer tanks of a double-shelled cryogenic tank with inert gas, a part of the space between the inner and outer tanks is replaced by the inert gas, and the inert gas used for the replacement is replaced. The active gas becomes a mixture with the replaced air and is discharged. As the process is repeated, the amount of air in the discharged mixture increases, so it is released into the atmosphere and replaced with new inert gas. By repeating the process of transporting gas to the cold insulating material, the cold insulating material is filled between the inner and outer tanks over time, and the amount of inert gas replacing the air gradually increases, causing the air to become inert over time. The effect is that the active gas can be completely replaced.

In addition, since inert gas is used to transport foamed cold insulation materials, the cold insulation materials do not absorb moisture or undergo denaturation during transportation, which has a negative impact on cool-down after tank completion, cooling function during operation, and tank performance. There is also the advantage of not having to give it.

[Brief explanation of the drawing]

Fig. 1 is a schematic partial cross-sectional side view of filling a cold insulator into a double-shell cryogenic tank based on the prior art, Fig. 2 and the following are explanatory diagrams of one embodiment of the present invention, and Fig. 2 is an implementation of the principle aspect. FIG. 3 is a schematic partial cross-sectional side view of an example, and FIG. 3 is a partial cross-sectional view of an implementation plant. 3...Double shell low temperature tank, 7...Outer tank, 6...
Inner tank, 10... Cold insulation material.

Claims (1)

[Claims] 1. In a method of constructing an outer tank and an inner tank of a double-shell low-temperature tank and filling a cold insulating material between the inner and outer tanks, the raw stone is fired on-site and the foamed cold insulating material is filled by gas transportation, after the raw rock is fired. The foamed cold insulating material is gas-transported using an inert gas and filled between the above-mentioned inner and outer tanks, and along with the filling, the air between the inner and outer tanks is replaced with the inert gas, and some of the inert gas is replaced. Only the mixture with air is discharged from between the inner and outer tanks, and the foamed cold insulation material is transported and filled into the inner and outer tanks again with the discharged mixture. During this process, the discharged mixture is discharged to the outside air and a new insulating material is created. A method for filling a double-shell low-temperature tank with a cold insulating material, characterized in that active gas is supplied and the foamed cold insulating material is transported so that inert gas replacement is completed when filling of the foamed cold insulating material is completed.