JPH0480280B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to cryogenic liquid storage tanks.

A conventional above-ground tank for storing low-temperature liquid has a structure as shown in FIG.

In other words, the tank A that stores liquid such as LP gas has a steel structure tank body A1, and the outer periphery of the tank body A1 is covered with a heat insulating material A2.
The outer periphery of the heat insulating material A2 is further covered with a protective layer A3 made of carbon steel or the like.

A liquid barrier B is arranged and formed around the tank A to prevent the low temperature liquid from flowing out.

In this case, if the available land is wide, it is possible to leave sufficient space around the tank and build a low dike around its outer periphery, but in order to make effective use of the narrow land, Tank A should be placed close to the tank and a high concrete dike constructed. A dike must be constructed.

Conventional tanks formed in this manner have the following disadvantages.

<B> The steel body A1 of tank A is made of an expensive steel material without low-temperature brittle properties in order to prevent low-temperature breakdown, and its outer surface is covered with a heat insulating material A2, and the outer surface is coated with a material such as carbon steel. It is covered with a protective layer A3.

Therefore, the construction cost of the tank becomes very high.

<B> If the stored liquid in the low-temperature liquid storage tank leaks, the outermost carbon steel will be destroyed at low temperature. Therefore, even though the outer circumferential surface is covered, it is essential to further install a liquid barrier B on the outside of the tank.

<C> The steel tank body A1 has a limited thickness, and the heat insulating material A2 and protective layer A3 cannot be expected to have sufficient strength, so they have the disadvantage of being vulnerable to shocks in terms of protection from flying objects.

An object of the present invention is to solve these problems and provide a low-temperature liquid storage tank that can reduce construction costs and has excellent safety.

That is, the present invention relates to a low-temperature liquid storage tank in which a concrete inner tank for storing low-temperature liquid is housed in a sealed concrete outer tank, and a heat insulating material is formed between the inner tank and the outer tank. It is.

Next, embodiments of the tank of the present invention will be described.

First, the tank 1 of the present invention is composed of an inner tank 2 and an outer tank 3, and each part will be explained below.

[B] Inner tank Inner tank 2 is a tank for storing low-temperature liquefied gas, etc.

The inner tank 2 is a cylindrical body with a top and bottom as shown in FIG. 1, and is made of prestressed concrete or reinforced concrete.

One of the features is that the inner tank 2 is made of concrete instead of steel.

The bottom plate of the inner tank 2 may be integrally formed of concrete, or a sealed body may be formed with the inner tank bottom plate 21 made of low-temperature steel.

As the steel material for low temperature use, for example, 9% nickel steel can be used.

A vapor barrier 22 made of steel or the like is installed on the outer peripheral surface of the inner tank 2.

[B] Outer tank The outer tank 3 is a sealed protective container for storing the inner tank 2 inside to protect the inner tank 2 from flying objects and to prevent the low-temperature storage liquid from flowing out. The bottom plate and the side wall connecting them are integrally provided.

The outer tank 3 is made of reinforced concrete or PC concrete.

The lower side wall of the outer tank 3 is connected to the outer tank bottom plate 4 by rigid connection or a hinge structure.

A heater 41 is arranged inside the bottom plate 4 to prevent freezing.

A heat insulating material 11 is laid over the entire inner peripheral surface of the outer tank 3 via a vapor barrier 5 made of carbon stainless steel, etc., to form a sealed body with excellent heat insulation, liquid tightness, and airtightness.

When storing the inner tank 2 in the outer tank 3, both tanks 2,
The space between the side walls of No. 3 is more than enough for a worker to pass through.

As a result, a continuous space is formed between the inner tank 2 and the outer tank 3, and this space is filled with nitrogen gas or the like to form a gas chamber 6.

One of the features of this embodiment is that a layer of heat insulating material 11 is formed on the entire inner wall of the outer tank 3.

As the heat insulating material 11, for example, styrofoam, polyurethane, etc. can be used, but it may also be filled with pearlite powder.

The reason why 11 layers of heat insulating material are formed on the inner surface of outer tank 3 is that when inner tank 2 is destroyed, the temperature of the low-temperature liquid is not suddenly transmitted to outer tank 3, and the temperature of outer tank 3 is maintained through 11 layers of heat insulating material. This is to prevent destruction and heat input from the outside.

However, tanks that store LPG do not necessarily require 11 layers of insulation.

Next, the storage condition of the tank will be explained.

[B] Normal times Under normal conditions, low-temperature liquid is stored in the inner tank 2.

In this case, since the gas chamber 6 is formed around the inner tank 2, the effect as a vapor barrier is greatly improved, and the product can be stored under good conditions.

Further, by periodically inspecting the inside of the gas chamber 6 and inspecting the inner tank 2 and the outer tank 3, the safety of the tank can be further improved.

[B] In the event of a leak If a crack occurs in the inner tank 2 and low temperature liquid flows out from the inner tank 2, the low temperature liquid will flow into the gas chamber 6.

If the outer tank 3 is simply made of concrete, there is a possibility that the temperature will be destroyed by sudden contact with low-temperature liquid, but in the case of the tank of this embodiment, the outer tank 3
Since 11 layers of heat insulating material with excellent heat insulation properties are formed on the inner wall of the tank, the thermal shock of the low-temperature liquid that has flowed out can be alleviated and destruction can be prevented.

Therefore, the outer tank 3 is not damaged by the temperature due to the layer of the heat insulating material 11, and the outflow of liquid can be completely prevented. Furthermore, the outer tank 3 not only prevents leakage of the low-temperature liquid, but also can restrict the diffusion of boil-off gas (evaporation and escape of liquefied gas) since it is formed into a sealed body.

[C] Other Examples It is also possible to adopt a tank as shown in Figure 2.

That is, an inner tank 2 without a ceiling with an open upper opening is housed in an outer tank 3 of a sealed body via a bottom heat insulating material 8.

A corrugated barrier 9 communicating to the ceiling of the outer tank 3 is placed at the upper opening of the inner tank 2 to divide the space between the two tanks 2 and 3 into two.

As a result, a sealed inner tank 2 is formed.

A continuous space is formed between the side walls of the inner tank 2 and the outer tank 3, and a gas chamber 6 is formed by filling nitrogen gas or the like in this space.

Furthermore, an inexpensive heat insulating material such as perlite is placed on the outer wall of the inner tank 2 to form a layer of heat insulating material 11.

A heat insulating material 53 made of glass wool or the like is placed on a deck plate suspended from the ceiling to prevent heat input from the ceiling.

There are also cases where the heat insulating material 53 is attached directly to the roof.

According to the tank of this embodiment, the following effects can be obtained.

<B> By installing the corrugated barrier 9, the roof of the outer tank 3 can be shared, and the roof can be formed into a single layer.

<B> There is no longer a need to construct a separate dike at a remote location around the outer tank 3.

<C> An inexpensive heat insulating material such as perlite can be used as the heat insulating layer, making it highly economical.

<D> When a carbon tail or the like is attached to the outer periphery of the outer tank 3, liquid tightness and airtightness are improved.

Since the present invention is as explained above, the following effects can be expected.

<B> Since a heat insulating material with excellent heat insulation properties is placed between the inner tank and the outer tank, even if the low temperature liquid in the inner tank leaks out, it is possible to prevent temperature breakdown in the outer tank.

Therefore, high tank safety can be obtained.

<B> The inner tank itself was constructed of concrete instead of steel.

As a result, it is no longer necessary to construct the tank using only steel as in the past, and it can be constructed using concrete, which is cheaper than steel, reducing construction costs.

<C> The inner tank was placed inside a sealed outer tank.

Therefore, when the stored liquid leaks from the inner tank, it is not only possible to simply prevent the leakage, but also to limit the diffusion of boil-off gas to a minimum.

<D> Since a space is formed between the side walls of the inner tank and the outer tank, the tank can be inspected even while the inner tank is being filled with low-temperature liquid.

<e> Since the gas chamber is formed in the space between the inner tank and the outer tank, the heat insulation effect can be clearly improved compared to the conventional structure shown in FIG.

Furthermore, by checking the gas concentration in the gas chamber, leak detection can be easily and accurately performed.

<f> Rather than simply attaching a roof to the dike, it was constructed by forming sealed tanks into a double structure with a space between the tanks.

Therefore, it is possible to prevent the intrusion of rainwater, ensure the moisture resistance of the protective layer, and improve the heat insulating effect of the protective layer.

<G> Even if deformation occurs due to temperature changes in the inner tank, since both tanks are insulated, the inner tank can be deformed and the outer tank will not be affected in any way.

<H> Since a heat insulating material made of glass wool or the like can be hung on the underside of the roof, inexpensive carbon steel or the like can be used as a barrier attached to the underside of the ceiling, and there is no need to use expensive nickel steel.

<li> Since the tank can be made of concrete, it has increased impact resistance and can prevent damage from flying objects.

[Brief explanation of the drawing]

FIG. 1: An explanatory diagram of one embodiment of a tank according to the present invention, FIG. 2: An explanatory diagram of a tank according to another embodiment, and FIG. 3: An explanatory diagram of a conventional tank. 1: Tank, 2: Inner tank, 3: Outer tank, 4: Bottom plate,
5: Roof, 6: Gas chamber.

Claims (1)

[Scope of Claims] 1. A concrete inner tank for storing a low-temperature liquid is housed in a concrete outer tank that is configured in a more airtight manner with a ceiling, a bottom plate, and a side wall connecting them, and between the inner tank and the outer tank. A low temperature liquid storage tank with a heat insulating layer formed on it.