JPH07310896A - Low-temperature liquid storage tank - Google Patents

Abstract

PURPOSE:To well store low-temperature liquid, and also to perform manufacturing and installing of an inner tank at a low cost by surrounding most of the inner tank excluding the bottom part by a vacuum adiabatic layer, and supporting the bottom part of the inner tank by a supporting table having low thermal conductivity in a non-vacuum layer on the lower part by the line contact or the point contact. CONSTITUTION:A low-temperature liquid storage tank 8 is constituted into a double shell structure composed of an inner tank 2 in which low-temperature liquid is to be stored and an outer tank 4 for surrounding the periphery of the inner tank through a cold reserving layer 7. In this case, the bottom part 2a of the inner tank 2 is formed into a flat bottom and installed on a supporting table 9 arranged on the bottom part of the outer tank 4. A diaphragm 11 provided with a corrugate part 10 capable of being expanded and contracted in the radial direction is annularly arranged between the inner tank 2 and the outer tank 4. Moreover, the upper part of the cold reserving layer 7, sectioned by the diaphragm 11 is formed on the vacuum adiabatic layer 12, similarly, the lower part is formed on a non-vacuum layer 13 having the same pressure as the gaseous phase pressure of the inner tank 2. The supporting table 9 is constituted by using a member having low thermal conductivity, so as to support the bottom part 2a of the inner tank 2 by the line contact or the point contact.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a cryogenic liquid storage tank.

[0002]

2. Description of the Related Art FIG. 6 shows an example of a conventional low temperature liquid storage tank, in which an inner tank 2 for substantially storing a low temperature liquid 1 is provided.
And an outer tank 4 surrounding the inner tank 2 via a cold insulation layer 3 having a predetermined thickness constitute a low-temperature liquid storage tank 5 having a double-shell structure, and the inner tank 2 is the outer tank 4 It is installed on a support base 6 made of a heat insulating and cold insulating material such as pearlite concrete, which is disposed on the bottom portion 4a.

Generally, such a low temperature liquid storage tank 5 is an LN.
It is used for mass storage of G etc., and the vapor phase pressure in the inner tank 2 is slightly higher than atmospheric pressure, whereas the cold insulation layer 3 is filled with pearlite grains and then nitrogen gas is added. Since it is kept at about atmospheric pressure by being sealed, the pressure difference between the inside of the inner tank 2 and the cold insulation layer 3 side is extremely small, and the design pressure of the inner tank 2 can be relatively small.

[0004]

However, if the low-temperature liquid 1 is about LNG (about -160 ° C), the low-temperature liquid storage tank 5 can sufficiently handle it, but liquid hydrogen at a lower temperature (-250 ° C or lower). In order to improve the heat insulation performance, it is necessary to evacuate the cold insulation layer 3 in order to increase the heat insulation performance, and the pressure difference between the inner tank 2 storing the low temperature liquid 1 and the evacuated insulation layer 3 side is Since it becomes larger and the design pressure of the inner tank 2 becomes larger, it becomes difficult to form the bottom portion 2a of the inner tank 2 into a flat bottom having a flat shape as shown in the figure, and the bottom portion 2a of the inner tank 2 is lowered. There is a problem that the cost required for manufacturing and installing the inner tank 2 rises because it is forced to form a spherical shape that bulges in the direction.

The present invention has been made in view of the above circumstances, and provides a low-temperature liquid storage tank capable of storing a low-temperature liquid such as liquid hydrogen at an extremely low temperature while the bottom of the inner tank is a flat bottom. It is intended to be provided.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a low-temperature liquid having a double-shell structure composed of an inner tank for storing a low-temperature liquid therein, and an outer tank surrounding the inner tank via a cold insulation layer. A storage tank, in which the bottom of the inner tank is formed into a flat bottom having a flat shape and is installed on a support table arranged at the bottom of the outer tank, the lower outer circumference of the inner tank and the lower inner circumference of the outer tank. A diaphragm having a corrugated portion that can be expanded and contracted in the radial direction is arranged in an annular shape, and the upper portion of the cold insulation layer partitioned by the diaphragm is evacuated to form a vacuum heat insulating layer and the lower portion is the inner portion. By filling an inert gas having a boiling point lower than the temperature of the low temperature liquid in the tank, a non-vacuum layer having substantially the same pressure as the gas phase pressure in the inner tank,
Further, it is characterized in that the support base is configured to support the bottom portion of the inner tank by line contact or point contact with a member having a low thermal conductivity.

Further, the support base may be constructed by assembling a hard synthetic resin plate material in a honeycomb or lattice shape in cross section, or by arranging a number of hard synthetic resin cylindrical materials in a recumbent manner. Alternatively, it is preferably constructed by arranging a large number of hard synthetic resin spherical members.

[0008]

Therefore, in the present invention, most of the inner tank excluding the bottom can be surrounded by a vacuum heat insulating layer having an extremely high heat insulating property, and the support base has a low thermal conductivity in the non-vacuum layer. Thus, the bottom portion of the inner tank is supported by the line contact or the point contact, so that the heat transfer through the support base can be significantly suppressed.

On the other hand, by enclosing the bottom portion of the inner tank with a non-vacuum layer having substantially the same pressure as the vapor phase pressure in the inner tank, the pressure difference between the inner tank and the non-vacuum layer side is reduced, and the inner tank is Since it is possible to suppress the design pressure at the bottom of the container to a relatively small value, it becomes possible to maintain the required strength while leaving the bottom of the inner tank flat and flat.

Further, the relative displacement between the outer tank and the inner tank caused by heat contraction when a low temperature liquid is poured into an empty inner tank, deformation caused when the vacuum insulation layer is evacuated, or the like is caused by a corrugated diaphragm. Since it is absorbed by the parts, it is possible to reliably hold the vacuum degree of the vacuum heat insulating layer and the pressure of the non-vacuum layer.

[0011]

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

FIGS. 1 and 2 show an embodiment of the present invention, in which parts designated by the same reference numerals as those in FIG. 6 represent the same parts.

As shown in the figure, a low temperature of a double shell structure is formed by an inner tank 2 which stores the low temperature liquid 1 therein and an outer tank 4 which surrounds the inner tank 2 through a cold insulation layer 7 having a predetermined thickness. A liquid storage tank 8 is configured, and the bottom portion 2a of the inner tank 2 is formed into a flat bottom having a flat shape, and the bottom portion 4a of the outer tank 4 is formed.
It is installed on the support base 9 arranged at.

Further, between the lower outer circumference of the inner tank 2 and the lower inner circumference of the outer tank 4, a diaphragm 11 having a corrugated portion 10 which can be expanded and contracted in the radial direction is formed, for example, of stainless steel or the like to form an annular shape. An upper part of the cold insulation layer 7 that is provided and partitioned by the diaphragm 11 serves as a vacuum heat insulating layer 12 by vacuuming, and a lower part of the cold insulation layer 7 is a low temperature inside the inner tank 2. By enclosing an inert gas having a boiling point lower than the temperature of the liquid 1, a non-vacuum layer 13 having substantially the same pressure as the gas phase pressure in the inner tank 2 is formed.

For example, when liquid hydrogen is stored as the low temperature liquid 1 in the inner tank 2 and the hydrogen gas pressure above the liquid surface in the inner tank 2 is slightly higher than atmospheric pressure, the non-vacuum is used. The layer 13 is filled with helium gas having a boiling point lower than that of the liquid hydrogen so that the pressure becomes substantially the same as the hydrogen gas pressure in the inner tank 2.

Here, the reason why the non-vacuum layer 13 is filled with an inert gas having a boiling point lower than the temperature of the low temperature liquid 1 in the inner tank 2 is that the low temperature liquid 1 in the inner tank 2 is cooled to liquefy the inert gas. Alternatively, it is for avoiding the solidification and for maintaining the pressure of the non-vacuum layer 13.

Further, as shown in FIG. 2, the support base 9 is constructed to have a required height by assembling a hard synthetic resin plate material 14 having a low thermal conductivity into a honeycomb cross section and laminating a plurality of layers. The honeycomb structure is fixed by shifting the half pitch of one side of the honeycomb for each stage so that the honeycomb structures are arranged in a staggered pattern on the upper and lower sides.

Thus, according to the structure of the low temperature liquid storage tank 8 described above, most of the inner tank 2 excluding the bottom portion 2a can be surrounded by the vacuum heat insulating layer 12 having extremely high heat insulating performance, and In the non-vacuum layer 13, the support base 9 is constructed by assembling a hard synthetic resin plate material 14 having a low thermal conductivity into a honeycomb cross section, so that the bottom portion 2a of the inner tank 2 has a high compressive strength. It is possible to support by contact, and it is possible to remarkably suppress heat transfer through the support base 9.

On the other hand, by enclosing the bottom portion 2a of the inner tank 2 with the non-vacuum layer 13 having substantially the same pressure as the inner pressure of the inner tank 2, the pressure difference between the inner tank 2 and the non-vacuum layer 13 side is reduced. Since the design pressure of the bottom portion 2a of the inner tank 2 can be suppressed to a relatively small value, it is possible to maintain the required strength while leaving the bottom portion 2a of the inner tank 2 a flat bottom. Become.

Further, the outer tank 4 and the inner tank 2 are relatively opposed to each other due to heat contraction when the low temperature liquid 1 is put into the empty inner tank 2 or deformation of the vacuum heat insulating layer 12 when vacuuming is performed. Displacement is diaphragm 1
Since it is absorbed by the corrugated portion 10 of No. 1, it is possible to reliably hold the vacuum degree of the vacuum heat insulating layer 12 and the pressure of the non-vacuum layer 13.

Therefore, according to the above-mentioned embodiment, the low temperature liquid 1 such as liquid hydrogen having an extremely low temperature can be stored with the bottom portion 2a of the inner tank 2 being a flat bottom having a flat shape.
It is possible to avoid soaring costs required for manufacturing and installing the inner tank 2.

The support base 9 may be constructed by assembling a hard synthetic resin plate material 14 in a cross-sectional lattice shape as shown in FIG. 3, and as shown in FIG. It may be configured by arranging 15 in a recumbent position, or by arranging a large number of hard synthetic resin spherical members 16 as shown in FIG.

The cryogenic liquid storage tank of the present invention is not limited to the above-mentioned embodiment, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0024]

According to the above-described low temperature liquid storage tank of the present invention, it is possible to store a low temperature liquid such as liquid hydrogen at an extremely low temperature while keeping the bottom of the inner tank flat. It is possible to obtain an excellent effect that it is possible to avoid a cost increase required for manufacturing and installing the tank.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention.

FIG. 2 is an enlarged perspective view of the support base of FIG.

FIG. 3 is an enlarged perspective view showing a modified example of a support base.

FIG. 4 is an enlarged perspective view showing another modified example of the support base.

FIG. 5 is an enlarged perspective view showing still another modified example of the support base.

FIG. 6 is a schematic view showing a conventional example.

[Explanation of symbols]

 1 Low Temperature Liquid 2 Inner Tank 2a Bottom 4 Outer Tank 4a Bottom 7 Cooling Layer 8 Low Temperature Liquid Storage Tank 9 Support Stand 10 Corrugate 11 Septa 12 Vacuum Insulation Layer 13 Non-Vacuum Layer 14 Hard Synthetic Resin Plate Material 15 Hard Synthetic Resin Cylindrical Material 16 Spherical material made of hard synthetic resin

Claims (4)

[Claims] 1. A double-shell structure low temperature liquid storage tank comprising an inner tank for storing a low temperature liquid therein, and an outer tank surrounding the inner tank with a cooling layer between the inner tank and the inner tank. The bottom of the tank is formed into a flat bottom having a flat shape, and the bottom is installed on a support table arranged at the bottom of the outer tank, and is expandable and contractible in the radial direction between the lower outer circumference of the inner tank and the lower inner circumference of the outer tank. A diaphragm with a corrugated portion is annularly arranged, and the upper portion of the cold insulation layer partitioned by the diaphragm is evacuated to form a vacuum heat insulating layer, and the lower portion is lower than the low temperature liquid temperature in the inner tank. A non-vacuum layer having almost the same pressure as the vapor phase pressure in the inner tank is created by filling the inside with an inert gas with a boiling point, and the bottom of the inner tank is line-contacted or point-contacted by a member having a low thermal conductivity for the support base. A low temperature liquid storage tank, which is configured to be supported by. 2. A low temperature liquid storage tank, characterized in that the support base is constructed by assembling a hard synthetic resin plate material in a honeycomb shape or a lattice shape in cross section. 3. A low temperature liquid storage tank, characterized in that the support base is constituted by arranging a large number of hard synthetic resin cylindrical members in a recumbent manner. 4. A low temperature liquid storage tank, characterized in that the support base is constituted by arranging a large number of hard synthetic resin spherical members.