KR20230024370A - double angle tank - Google Patents

Abstract

The double-shell tank is a granular shape in which a storage unit for storing liquid in a sealed state is formed in a space surrounded by a spherical shell-shaped inner tank, an outer tank covering the inner tank, and an outer wall of the inner tank and an inner wall of the outer tank to form a heat insulating layer. Provide insulation. Further, the size of the gap between the tops of the inner shell and the outer shell is equal to or greater than the value obtained by adding the level difference between the granular heat insulators in the state in which the inner shell is empty and in the state in which the liquid is contained, to the size of the gap between the bottom portions of the inner shell and the outer shell.

Description

double angle tank

The present invention relates to the structure of a double shell tank having an outer tank and an inner tank.

Conventionally, as a tank for storing a low-temperature liquid, a double-shell tank is known. A double-shell tank generally includes an inner tank substantially containing a low-temperature liquid, an outer tank covering the inner tank from the outside at a predetermined interval, and a heat insulating layer formed between the inner tank and the outer tank. The heat insulating layer is formed of, for example, a granular heat insulating material filled between an inner shell and an outer shell, and pearlite is used as the granular heat insulating material.

At the time of drying the double shell tank, after the inner and outer shells are completed, a granular heat insulating material is filled to fill the space between the inner shell and the outer shell in a state where the inner shell is empty. Therefore, when a low-temperature liquid is supplied to the inner shell and the inner shell thermally shrinks, the gap between the inner shell and the outer shell widens, and there is a possibility that the granular heat insulating material filled between the inner shell and the outer shell settles. When the granular heat insulating material settles, a space in which the granular heat insulating material does not exist is created at the tank top of the double shell tank, and the thickness of the heat insulating layer at the tank top is reduced. When a location where the thickness of the heat insulating layer is insufficient occurs in the double shell tank, the thermal insulation properties of the location are lowered. As a result of the decrease in thermal insulation properties, cold heat in the inner shell is transferred to the outer shell, which may cause frost in the outer shell and cause corrosion of the outer shell. In addition, when the amount of heat input into the inner tank increases due to the decrease in the heat insulating property, the amount of boil-off gas of the low-temperature liquid increases, and there is a possibility that the pressure in the inner tank may become excessive.

Therefore, in the double shell tank of Patent Literature 1, an inner heat insulating layer formed of an elastic material (glass wool) that can be stretched in the radial direction of the inner tank, and an outer heat insulating layer formed of a filler (perlite) are provided with a heat insulating layer composed of two layers. . In such a double shell tank, gaps formed in the heat insulating layer due to thermal contraction of the inner shell are filled with the expanding elastic material, and sedimentation of the filler material is suppressed.

Japanese Unexamined Patent Publication No. 2013-238285

In particular, in a double-shell tank installed outdoors, it is important to suppress the amount of heat input to the top of the tank due to solar radiation. Nevertheless, if the heat insulating layer between the inner shell and the outer shell is formed of the granular heat insulating material, the heat insulating property of the top portion of the tank is lowered due to sedimentation of the granular heat insulating material as described above.

According to the double shell tank of the said patent document 1, although sedimentation of a granular heat insulating material (filler) can be suppressed, cost increases since a lot of expensive glass wool is used compared with perlite.

The present invention has been made in view of the above circumstances, and its object is to form a heat insulating layer between an inner shell and an outer shell by means of a granular heat insulating material, and to form a heat insulating layer having an appropriate thickness at the top of the tank even after the granular heat insulating material has settled due to shrinkage deformation of the inner shell. It is to provide a double-shell tank that is compatible with maintaining the

A double shell tank according to an embodiment of the present invention includes an inner tank in the shape of a spherical shell in which a storage unit for storing liquid in a sealed state is formed therein, an outer tank covering the inner tank, an outer wall of the inner tank, and the inner tank. A granular heat insulating material filling a space enclosed by an inner wall of the outer shell to form a heat insulating layer, wherein a size of a gap between the top of the inner shell and the top of the outer shell in a state in which the inner shell is empty is ) greater than or equal to a value obtained by adding a level difference between the granular insulator in a state in which the inner tub is empty and in a state in which the inner tub contains the liquid, to the size of the gap.

According to the double-shell tank, since the gap at the top is larger than the gap at the bottom, a heat insulating layer thicker than that at the bottom of the tank is formed at the top of the tank when the inner tank is empty. Then, when the low-temperature liquid is supplied to the inner shell and the inner shell shrinks, the gap between the inner shell and the outer shell expands, and the granular insulator filled between the inner shell and the outer shell settles, but even in the state where the granular insulator settles, the thickness is sufficient for the top of the tank. of the insulating layer is maintained. Therefore, according to the double shell tank, it is possible to achieve both the formation of a heat insulating layer between the inner shell and the outer shell by the granular heat insulating material and the maintenance of the heat insulating layer having an appropriate thickness at the top of the tank even after the granular heat insulating material settles due to the shrinkage deformation of the inner shell. can

In the double shell tank, the outer shell may have a spherical shell shape, and the center of the outer shell may be located above the center of the inner shell.

In this way, by eccentricing the center of the inner shell downward with respect to the center of the outer shell, while both the outer shell and the inner shell have a spherical shell shape with excellent strength, the size of the top gap between the inner shell and the outer shell is the size of the bottom gap between the inner shell and the outer shell. can be bigger

Alternatively, in the double-shell tank, the outer tank includes a lower spherical shell portion, an upper spherical shell portion, and a tubular body connecting the lower spherical shell portion and the upper spherical shell portion. The center of the inner tub and the center of the lower spherical shell portion may coincide.

Accordingly, below the equator of the inner tank, a heat insulating layer having a certain thickness is formed around it. Above the equator of the inner shell, a heat insulating layer thicker than the heat insulating layer below the equator of the inner shell is formed around it. In addition, the outer shell has a shape close to that of a spherical shell, so that the outer shell can have sufficient strength.

Alternatively, in the double-shell tank, the outer shell is composed of a body portion having a spherical shell shape and a dome portion installed on the top of the body portion and filled with the granular insulator, and the center of the inner shell coincides with the center of the body portion. also good

In this way, since the dome portion filled with the granular insulating material is provided at the top of the main body of the outer shell, even if the granular insulator filled between the inner shell and the main body of the outer shell settles due to shrinkage and deformation of the inner shell, the sediment is filled in the dome. supplemented by the existing granular insulation. Therefore, even in the state where the granular heat insulating material has settled, a heat insulating layer of sufficient thickness is maintained at the top of the tank.

According to the present invention, it is possible to form a heat insulating layer between the inner shell and the outer shell by the granular heat insulating material and maintain the heat insulating layer having an appropriate thickness at the top of the tank even after the granular heat insulating material sinks due to shrinkage deformation of the inner shell. Tanks can be provided.

[Fig. 1] Fig. 1 is a sectional view showing the overall configuration of an empty double shell tank according to a first embodiment of the present invention.
[Fig. 2] Fig. 2 is a cross-sectional view of a double-shell tank showing a state in which low-temperature liquid is supplied to the inner tank shown in Fig. 1;
[Fig. 3] Fig. 3 is a sectional view showing the overall configuration of an empty double shell tank according to a second embodiment of the present invention.
[Fig. 4] Fig. 4 is a cross-sectional view of the double shell tank showing a state in which low-temperature liquid is supplied to the inner tank shown in Fig. 3;
[Fig. 5] Fig. 5 is a sectional view showing the overall configuration of an empty double shell tank according to a third embodiment of the present invention.
[Fig. 6] Fig. 6 is a cross-sectional view of the double-shell tank showing a state in which low-temperature liquid is supplied to the inner tank shown in Fig. 5;

[First Embodiment]

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. 1 is a cross-sectional view showing the overall configuration of an empty double-shell tank 1A according to a first embodiment of the present invention, and FIG. 2 is a low-temperature liquid 7 supplied to the inner tank 2 shown in FIG. It is a sectional view of the double shell tank 1A showing the state.

The double shell tank 1A shown in FIGS. 1 and 2 is a tank for storing a low-temperature liquid 7 such as liquid hydrogen, liquid nitrogen, or liquefied natural gas. The double-legged tank 1A is installed on a hull or the ground in a state supported by skirts or posts not shown.

The double shell tank 1A includes an inner tank 2, an outer tank 3 covering the inner tank 2, and a granular heat insulating material 4 filled between the inner tank 2 and the outer tank 3 to form a heat insulating layer. and a vacuum pump 6 for vacuuming the space between the inner tub 2 and the outer tub 3.

The inner tub 2 has a hollow spherical shell shape, and is formed by welding, for example, a large number of SUS panels. A storage unit 21 is formed inside the tub 2 to store the low-temperature liquid 7 in a hermetically sealed state. The inner tub 2 can allow shrinkage, deformation and recovery of deformation due to a temperature difference between room temperature when the tank is dried and low temperature when the low temperature liquid 7 is accommodated.

The outer shell 3 has a hollow spherical shell shape larger than the inner shell 2, and is formed by welding, for example, a plurality of steel plates. The outer shell (3) has a larger diameter than the inner shell (2). The inner tank 2 is supported on the outer tank 3 by rods (not shown) connecting between the outer wall of the inner tank 2 and the inner wall of the outer tank 3.

The granular heat insulating material 4 is filled in the space enclosed by the outer wall of the inner tank 2 and the inner wall of the outer tank 3 in a compacted state. The granular heat insulating material 4 is granular pearlite, for example. However, as the granular heat insulating material 4, well-known granular heat insulating materials other than pearlite may be employ|adopted.

The space filled with the granular heat insulating material 4 between the inner tank 2 and the outer tank 3 is forcibly evacuated by the vacuum pump 6 and is brought into a substantially vacuum state. Thus, when the space filled with the granular heat insulating material 4 becomes a substantially vacuum state, the heat insulating effect further increases.

A vertical line passing through the center 3c of the outer shell 3 and a vertical line passing through the center 2c of the inner shell 2 coincide with the tank center line C of the double shell tank 1A. At the bottom of the tank, the gap between the inner wall of the outer tank 3 and the outer wall of the inner tank 2 at the center line C of the tank is called "bottom gap G1". In addition, the gap between the inner wall of the outer tank 3 and the outer wall of the inner tank 2 at the tank center line C at the top of the tank is called a "top gap G2".

In the double shell tank 1A according to this embodiment, the inner tank 2 and the outer tank 3 are arranged so that the top gap G2 is larger than the bottom gap G1. That is, the inner tub 2 and the outer tub 3 are arranged such that the center 3c of the outer tub 3 is located above the center 2c of the inner tub 2. Here, the center 3c of the outer shell 3 is the center of the spherical shell shape of the outer shell 3, and the center 2c of the inner shell 2 is the center of the spherical shell shape of the inner shell 2.

In the state where the inner tank 2 is empty, the size L2 of the top gap G2 is equal to the size L1 of the bottom gap G1, compared to the state where the inner tank 2 is empty (FIG. 1) and the inner tank 2 are empty. (2) is more than the value which added the level difference (DELTA)L of the granular heat insulating material 4 of the state (FIG. 2) which accommodated the low-temperature liquid 7. That is, the following Equation 1 holds. Here, “a state in which the inner tank 2 contains the low-temperature liquid 7” means that the low-temperature liquid 7 is accommodated in the storage unit 21 up to a predetermined full level (or up to an arbitrary standard level). condition is good

L2 > L1 + ΔL ... (Formula 1)

Level difference (DELTA)L (namely, the sedimentation amount of the granular heat insulating material 4) can be calculated|required by calculation or simulation.

As described above, the double shell tank 1A according to the present embodiment includes a spherical shell-shaped inner tank 2 having a storage unit 21 for storing the low-temperature liquid 7 in a sealed state therein, An outer shell (3) covering the inner tube (2), and a granular heat insulating material (4) filling the space surrounded by the outer wall of the inner shell (2) and the inner wall of the outer shell (3) to form a heat insulating layer. The size L2 of the top gap G2 between the inner shell 2 and the outer shell 3 is equal to the size L1 of the bottom gap G1 between the inner shell 2 and the outer shell 3. ) is equal to or greater than the sum of the level difference (ΔL) between the empty state and the granular heat insulating material 4 in the state where the inner tub 2 contains the low-temperature liquid 7.

In the double-shell tank 1A, since the size L2 of the top gap G2 is larger than the size L1 of the bottom gap G1, in the state where the inner tank 2 is empty, the top of the tank is placed at the bottom of the tank. A heat insulating layer thicker than the portion is formed (see FIG. 1). When the low-temperature liquid 7 is supplied to the inner tub 2 and the inner tub 2 shrinks, the gap between the inner tub 2 and the outer tub 3 widens, causing a gap between the inner tub 2 and the outer tub 3. The filled granular heat insulating material 4 settles, but even in the state where the granular heat insulating material 4 settles, the heat insulating layer of sufficient thickness L2' is maintained at the tank top part (refer FIG. 2).

As described above, according to the double shell tank 1A according to the present embodiment, the insulating layer is formed between the inner shell 2 and the outer shell 3 by the granular heat insulating material 4 and the contraction and deformation of the inner shell 2 is caused. Even after the sea granular heat insulating material 4 settles, it is compatible with maintaining the heat insulating layer of appropriate thickness L2' in the tank top part.

In addition, in the double shell tank 1A according to this embodiment, the outer shell 3 has a spherical shell shape, and the center 3c of the outer shell 3 is located above the center 2c of the inner shell 2. do.

In this way, the center 2c of the inner shell 2 is eccentric downward with respect to the center 3c of the outer shell 3, so that both the outer shell 3 and the inner shell 2 have a spherical shell shape with excellent strength, The size (L2) of the top gap (G2) between (2) and the outer shell (3) can be made larger than the size (L1) of the bottom gap (G1) between the inner shell (2) and the outer shell (3).

[Second Embodiment]

Next, a second embodiment of the present invention will be described. Fig. 3 is a cross-sectional view showing the overall configuration of an empty double-shell tank 1B according to a second embodiment of the present invention. FIG. 4 is a cross-sectional view of the double-shell tank 1B showing a state in which the low-temperature liquid 7 is supplied to the inner tank 2 shown in FIG. 3 . On the other hand, in the description of this embodiment, the same reference numerals are assigned to members identical or similar to those of the first embodiment, and detailed descriptions are omitted.

As shown in FIGS. 3 and 4 , the double tank 1B according to the present embodiment is a spherical shell-shaped inner tank having a storage unit 21 for storing the low-temperature liquid 7 in a sealed state therein. (2), an outer shell (3) covering the inner tube (2), and a granular heat insulating material (4) filling the space surrounded by the outer wall of the inner shell (2) and the inner wall of the outer shell (3) to form a heat insulating layer.

The outer shell 3 consists of a lower spherical shell portion 31, an upper spherical shell portion 32, and a tubular body portion 33 connecting the lower spherical shell portion 31 and the upper spherical shell portion 32 in the vertical direction. It is done. The lower spherical shell portion 31, the upper spherical shell portion 32, and the body portion 33 have the same diameter, and the diameter is larger than that of the inner tub 2.

The inner tub 2 and the outer tub 3 are arranged such that the center 2c of the inner tub 2 coincides with the center 31c of the lower spherical shell portion 31. The inner tank 2 is supported on the outer tank 3 by rods (not shown) connecting between the outer wall of the inner tank 2 and the inner wall of the outer tank 3.

As described above, in the double-shell tank 1B according to the present embodiment, the outer tank 3 includes the lower spherical shell portion 31, the upper spherical shell portion 32, the lower spherical shell portion 31, and the upper spherical shell portion. It consists of a tubular body portion 33 connecting the 32, and the center 2c of the inner tub 2 and the center 31c of the lower spherical shell portion 31 coincide.

In the double shell tank 1B, a heat insulating layer having a certain thickness is formed around the equator below the equator of the inner tank 2, and above the equator of the inner tank 2 around the equator. A heat insulating layer thicker than the heat insulating layer on the lower side is formed. In this way, the size L2 of the top gap G2 between the inner shell 2 and the outer shell 3 is equal to the size L1 of the bottom gap G1 between the inner shell 2 and the outer shell 3. The simple structure of the double tank 1B, which is equal to or greater than the sum of the level difference (ΔL) between the state in which (2) is empty and the state in which the inner tank (2) contains the low-temperature liquid (7), is added. are realizing Furthermore, the inner shell 2 is shaped like a spherical shell, and the outer shell 3 is also not a spherical shell, but can be made into a shape close to that of a spherical shell, so that the outer shell 3 can have sufficient strength.

[Third Embodiment]

Next, a third embodiment of the present invention will be described. Fig. 5 is a cross-sectional view showing the overall configuration of an empty double-shell tank 1C according to a third embodiment of the present invention. FIG. 6 is a cross-sectional view of the double-shell tank 1C showing a state in which the low-temperature liquid 7 is supplied to the inner tank 2 shown in FIG. 5 . On the other hand, in the description of this embodiment, the same reference numerals are assigned to members identical or similar to those of the first embodiment, and detailed descriptions are omitted.

As shown in FIGS. 5 and 6, the double shell tank 1C according to the present embodiment is a spherical shell-shaped inner tank having a storage unit 21 for storing the low-temperature liquid 7 in a sealed state therein. (2), an outer shell (3) covering the inner tube (2), and a granular heat insulating material (4) filling the space surrounded by the outer wall of the inner shell (2) and the inner wall of the outer shell (3) to form a heat insulating layer.

The outer shell 3 is composed of a body portion 35 having a spherical shell shape and a dome portion 36 installed at the top of the body portion 35. Although the shape of the dome part 36 is not specifically limited, For example, the shape which reversed the pod upside down may be sufficient. When it is assumed that the dome portion 36 does not exist, the volume of the void generated at the top of the body portion 35 due to the sedimentation of the granular insulator 4 of the body portion 35 due to the contraction and deformation of the inner tub 2 Let be ΔV. The volume of the dome portion 36 is greater than ΔV. That is, the dome portion 36 is filled with the granular heat insulating material 4 having a larger volume than ΔV.

The inner tub 2 and the outer tub 3 are arranged such that the center 2c of the inner tub 2 coincides with the center 35c of the main body 35. The inner tank 2 is supported on the outer tank 3 by rods (not shown) connecting between the outer wall of the inner tank 2 and the inner wall of the outer tank 3.

As described above, in the double-shell tank 1C according to the present embodiment, the outer tank 3 includes a body portion 35 having a spherical shell shape and a dome portion 36 installed at the top of the body portion 35. and the center 2c of the inner tub 2 coincides with the center 35c of the main body 35.

In the double shell tank 1C, a dome portion 36 filled with the granular heat insulating material 4 is provided on the top of the main body portion 35 of the outer shell 3. In this way, the size L2 of the top gap G2 between the inner shell 2 and the outer shell 3 is equal to the size L1 of the bottom gap G1 between the inner shell 2 and the outer shell 3. The simple structure of the double tank 1B, which is equal to or greater than the sum of the level difference (ΔL) between the state in which (2) is empty and the state in which the inner tank (2) contains the low-temperature liquid (7), is added. are realizing

In the double shell tank 1C, even if the inner tank 2 shrinks and deforms and the granular heat insulating material 4 filled between the main body 35 of the inner tank 2 and the outer tank 3 settles, The sediment is supplemented by the granular heat insulating material 4 filled in the dome portion 36. Therefore, even in the state where the granular heat insulating material 4 is settled, a heat insulating layer having a sufficient thickness (L2') is maintained on the upper part of the tank.

Although preferred embodiments of the present invention have been described above, the present invention may also include changes in the specific structure and/or function details of the above embodiments within a range not departing from the spirit of the present invention.

1A, 1B, 1C: Double angle tanks
2: housekeeper
2c: center of inner help
3: Outlaw
3c: center of extrinsic
4: granular insulation
6: vacuum pump
7: low-temperature liquid
21: storage unit
31: lower half spherical shell
31c: center of the lower half spherical shell
32: upper half spherical shell
33: torso
35: body part
35c: center of the main body
36: dome
C: tank center line
G1: bottom gap
G2: top gap
ΔL: level difference

Claims (4)

An inner container having a spherical shell shape formed therein with a storage unit for storing liquid in a sealed state;
an outer shell covering the inner shell;
A granular heat insulating material filling the space surrounded by the outer wall of the inner tank and the inner wall of the outer tank to form a heat insulating layer,
The size of the gap between the top of the inner shell and the outer shell when the inner shell is empty is the size of the gap between the inner shell and the bottom of the outer tube, the size of the gap between the empty shell and the liquid in the inner shell. A double-shell tank, characterized in that more than the value added to the level difference of the granular insulation. According to claim 1,
The outer shell has a spherical shell shape, and the center of the outer shell is located above the center of the inner shell. According to claim 1,
The outer shell is composed of a lower spherical shell portion, an upper spherical shell portion, and a cylindrical body connecting the lower spherical shell portion and the upper spherical shell portion, and the center of the inner shell coincides with the center of the lower spherical shell portion. double angle tank made with According to claim 1,
The outer tank is composed of a body portion having a spherical shell shape and a dome portion installed on the top of the body portion and filled with the granular heat insulating material, and the center of the inner tank and the center of the body portion coincide.

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