JPS5849757B2 - Low temperature liquefied gas storage tank - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a low-temperature liquefied gas storage tank, and more particularly to a thin-film type low-temperature liquefied gas storage tank that uses an inner tank having a thin-film structure as a portion that directly receives low-temperature liquefied gas.

One typical structure of a low-temperature liquefied gas storage tank is
A structure having an outer tank having a rigid structure, a compression-resistant heat insulating layer provided inside the outer tank, and an inner tank having a thin film structure provided inside the heat insulating layer is known.

A tank having such a structure is usually called a thin film tank or a membrane tank.

The inner tank having such a thin film structure is usually formed from a plate material of a low temperature resistant metal such as anohenium, stainless steel, nickel steel, etc. and having a thickness of about 1 m to 3 m.

Therefore, the inner tank is generally not self-supporting, and is formed so that when liquid is loaded inside and liquid pressure is applied, it is in moderate contact with the heat insulating layer and the pressure is received by the outer tank through the heat insulating layer. has been done.

In addition, when the thin film inner tank is generally shaped into a cylindrical shape, large stress due to temperature changes may be applied to such a thin film inner tank, in addition to liquid pressure, so complex wrinkles should be provided to absorb temperature changes. There are many.

As mentioned above, the conventional thin film inner tank has a thickness of 1 mm or more.
It is difficult to weld because it is thin, and the work is time-consuming because it is not self-supporting.Furthermore, as mentioned above, complicated wrinkles have to be created to absorb temperature changes. The problem is that wrinkles may cause damage to the tank.

Therefore, the present invention addresses the above-mentioned problems in a cylindrical thin-film type low-temperature liquefied gas storage tank installed on land.
A new type of low-temperature liquefaction that gives the inner tank a certain degree of independence during construction without greatly reducing the internal volume compared to a cylindrical tank, and allows the inner tank to expand and contract in a favorable manner due to temperature changes. It is intended to provide gas storage tanks.

According to the present invention, this purpose is to provide an outer tank having a rigid structure, a compression-resistant heat insulating layer provided inside the outer tank, and an inner tank having a thin film structure provided inside the heat insulating layer. The outer tank includes a substantially cylindrical outer shell and a substantially angular cylindrical inner shell having a groove recessed radially outward along a ridge line of the inner shell, It has a rectangular cylinder shape corresponding to the rectangular cylinder shape of the inner shell of the outer tank, and its plane part is directly supported by the outer tank via the heat insulating layer, and its ridgeline part has its own hoops. This is achieved by a low temperature liquefied gas storage tank characterized in that it is supported by the outer tank under tension.

According to the above configuration, the inner tank is substantially shaped into a rectangular cylinder shape, and thereby is given independence due to the cooperation of the flat part and the ridgeline part, and each of them is supported by tension. Expansion and contraction of the inner tank due to temperature changes can be easily absorbed in the ridgeline portion that is not in direct contact with the heat insulating layer.

Furthermore, according to this configuration, the outer tank has a triangular truss-like support extending between the ridgeline portions of the prismatic cylindrical shape by a combination of a substantially cylindrical outer shell and a substantially prismatic inner shell. Because it has a beam structure, it is able to stably support the internal pressure acting on the flat surface of the inner tank, and at the same time, when such a low-temperature liquefied gas tank is constructed as an underground tank, the surrounding soil freezes and the outside is exposed. Even when a large freezing pressure is applied to the tank from the outside, a strong support structure can be obtained that can safely receive this pressure.

1. Workers and equipment can enter and exit the groove provided along the ridgeline, and this makes it possible to carry out construction and inspection of the inner tank along the ridgeline from outside.

1) Since there is no need to create complicated wrinkles during construction, large plates can be assembled by welding, and they also have a certain degree of independence when constructed at room temperature, making construction relatively easy and requiring less on-site work. construction time can be shortened due to

The invention will now be described in detail by way of example embodiments with reference to the accompanying drawings.

FIG. 1 attached herewith is a plan cross-sectional view showing one embodiment of a low temperature liquefied gas storage tank according to the present invention.

In this figure, only half of the planar cross-sectional structure is shown because it is symmetrical about one diameter.

2 and 3 are vertical cross-sectional views of the tank taken along lines 1--2 and 1-1 in FIG. 1, respectively.

In these figures, only half of the structure is shown because the cross-sectional structure is symmetrical.

In these figures, reference numeral 1 denotes an outer tank having a rigid structure, which includes an outer shell 2 having a substantially cylindrical shape and an inner shell 3 having a substantially square tubular shape, in this embodiment a hexagonal tubular shape. I'm here.

A groove 4 recessed radially outward is formed along the ridgeline of the inner shell.

These outer and inner shells are connected to each other by connecting members such as ribs 5 and 6, and together with these connecting members constitute a strong support beam structure in the form of a triangular truss.

A compression-resistant heat insulating layer 7 is provided inside the outer tank 1 along the inner shell 3.

Such compression-resistant thermal insulation layers have themselves already been proposed and implemented in various embodiments.

The heat insulating layer 7 forms a groove 8 corresponding to the groove 4 in a portion along the groove 4 of the inner shell.

Inside the heat insulating layer 7, along the inner shell 3 of the heat insulating layer or the outer tank, there is an inner tank with a thin film structure having a rectangular cylinder shape corresponding to the rectangular cylinder shape, that is, a hexagonal cylinder shape in this embodiment. 9 is provided.

The inner tank 9 is usually made of a thin plate of about 8 wrL, although it is not limited to a material having low temperature resistance such as stainless steel.

The inner tank 9 is in direct contact with the heat insulating layer 7 on its flat surface, and the liquid pressure and gas pressure exerted from the low-temperature liquefied gas charged inside the inner tank are transferred to the outer tank through the compression-resistant heat insulating layer 7. Tell 1,
It is designed to be directly supported by the outer tank.

On the other hand, the portion 9a of the inner tank 9 facing the groove 4 of the inner shell 2 or the groove 8 of the heat insulating layer 7 along it is supported by the outer tank through its own hoop tension. .

As shown in FIG. 3, the inner shell 3 of the outer tank 1 has a support surface curved into a cylindrical shape at the bottom peripheral edge 3a located at the boundary between the side wall and the bottom wall. The heat insulating layer 7 also has a cylindrical surface along this line, and the inner tank 9 is also made to have a cylindrical surface along the cylindrical inner surface of the heat insulating layer at its ridgeline portion 9b along the line.

As shown in FIG. 2, the inner tank 9 is supported by its own hoop tension in the portion along the groove 8 of the heat insulating layer as described above.

Furthermore, as shown in FIG. 3, a corner 9c where a vertically extending ridge 9a of the inner tank and two ridges along the bottom join together is formed into a spherical shape.

The upper part of the inner tank 9 continues to the ceiling part 9e through a curved part 9d similar to the bottom part, and a cylindrical port part 9 is provided in the center of the ceiling part.
f is connected.

The outer tank 1 consists of a bottom part 1as, a side wall part 1b, and a ceiling part 1c, and a flange part 1d is provided at the center of the ceiling part to support a port part 9f of the inner tank.

The ceiling part 1c is given rigidity by a plurality of ribs 10 extending in the radial direction from the flange part 1d, and is supported by the side wall part 1d at its peripheral edge.

The heat insulating layer 7 is provided over the entire area where the outer tank and the inner tank overlap and is interposed therebetween.

In case of a large storage tank, the outside of the ridgeline and corners may be supported by supporting members as appropriate, taking into consideration the hydraulic pressure.

The supporting member may be pressed inward during normal temperature construction so that the supporting member can comfortably support the ridgeline and corner portions of the inner tank during low-temperature loading.

In either case, it is preferable to suspend the inner tank from the ceiling by an appropriate method.

In the above, the present invention has been described in detail with respect to one embodiment in which the inner tank has a hexagonal cylindrical shape, but the present invention is not limited to this embodiment, and various modifications may be made within the scope of the present invention. It is clear to those skilled in the art that embodiments are possible.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view showing one embodiment of a low-temperature liquefied gas storage tank according to the present invention, and FIGS. 2 and 3 are sections of the tank taken along lines ■-■ and ■--■ in FIG. 1, respectively. FIG. 1... Outer tank, 1a, 'ib, 1c, 1d-bottom, side wall, ceiling, flange of outer tank, 2... Outer shell,
3... Inner shell, 4... Groove, 5, 6... Rib, 7...
・Insulating layer, 8... Groove, 9... Inner tank, 9 a, 9
b, 9d: ridgeline of the inner tank, 9c: corner of the inner tank, 9e: ceiling of the inner tank, 9f: port of the inner tank, 10: rib.

Claims (1)

[Claims] 1 It has an outer tank with a rigid structure, a compression-resistant heat insulating layer provided inside the outer tank, and an inner tank with a thin film structure provided inside the heat insulating layer, and the outer tank has a substantially The inner shell includes a cylindrical outer shell and an inner shell that is substantially rectangular and has a groove recessed radially outward along the ridgeline thereof, and the inner tank is formed of a rectangular cylinder of the inner shell of the outer tank. It has a rectangular cylinder shape corresponding to the shape, and its plane part is directly supported by the outer tank through the heat insulating layer, and its ridgeline part is supported by the outer tank through its own hoop force. A low temperature liquefied gas storage tank characterized in that it is supported.