JP2012112474A - Support structure of vertical cryogenic liquid storage tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate over-specifications of a support skirt, and to improve constructibility by simplifying a structure in the vicinity of a part supporting an outer tank of the support skirt.SOLUTION: An inner tank for storing a cryogenic liquid is supported on a foundation through a support skirt 5, and an outer tank 10 surrounding the inner tank 1 is supported to the support skirt. The support skirt is divided into an inner-tank skirt part on the upper side and an outer-tank skirt part on the lower side. The plate thickness of the inner-tank skirt part is set to be smaller than that of the outer-tank skirt part. An annular plate doubling as a radiator plate is interposed between the inner-tank skirt part and the outer-tank skirt part. To the outer-tank annular plate, a bottom plate 15 of the outer tank is supported, and a cone 14 extending to the lower side from a side plate of the outer tank is supported.

Description

  The present invention relates to a support structure for a vertical cryogenic liquid storage tank.

  As a support structure for a storage tank that stores a low-temperature liquid such as liquid nitrogen, liquid oxygen, or LNG, the following Patent Document 1 describes that a vertical inner tank that stores a low-temperature liquid is supported on a foundation via a support skirt. An outer tank surrounding the tank is provided, a bottom plate of the outer tank is connected to the support skirt, and a heat dissipation / reinforcement ring member is provided on the outer periphery of the support skirt. A structure connected by cones is described.

JP 2001-153298 A

In the support structure of the vertical cryogenic liquid storage tank disclosed in Patent Document 1 described above, the support skirt made of stainless steel, which is resistant to low temperatures but relatively expensive, reaches from the lower end of the inner tank to the foundation and is constant. It was arranged with the plate thickness of, and was over-spec.
In addition, at the height position with the support skirt, the bottom plate of the outer tub is connected to the inside of the support skirt via an intermediate member, and the cone is connected to the outside of the support skirt via a heat dissipation and reinforcing ring. The intermediate member interposed between the support skirt and the bottom plate of the outer tub and the heat dissipating / reinforcing ring member interposed between the support skirt and the cone may be narrow, so that there is a support skirt. A plurality of members are concentrated at the height position, and there is a problem that the structure of the portion is complicated.
Further, as described above, a plurality of members are concentrated at a certain height position of the support skirt, and these members must be welded to each other, so that a welding operation in a narrow space is forced, and workability is poor. There was also a problem.

  The present invention has been made in view of such problems, and it is possible to eliminate the overspec of the support skirt and simplify the structure in the vicinity of the portion supporting the outer tub of the support skirt to improve the workability. Provided is a vertical cryogenic liquid storage tank support structure that can be realized.

  In the support structure for the vertical cryogenic liquid storage tank according to the present invention, the inner tank for storing the cryogenic liquid is supported on the foundation via the support skirt, and the outer tank surrounding the inner tank is supported by the support skirt. In the support structure of the vertical cryogenic liquid storage tank, the support skirt is divided into an upper inner tank skirt part and a lower outer tank skirt part, and the thickness of the inner tank skirt part is equal to that of the outer tank skirt part. An annular plate which is set to be smaller than the plate thickness and serves also as a heat radiating plate is interposed between the inner tank skirt portion and the outer tank skirt portion.

According to the support structure of the vertical cryogenic liquid storage tank, the support skirt is divided into an upper inner tank skirt part and a lower outer tank skirt part, and the strength of the inner tank skirt part and the outer tank skirt part, respectively. It is possible to make the plate thickness suitable for. That is, the inner tank skirt portion can be set to a certain plate thickness, and the outer tank skirt portion can be set thicker than the plate thickness of the inner tank skirt portion.
An annular plate that also serves as a heat sink is interposed between the inner tank skirt part and the outer tank skirt part, and cold heat transmitted from the inner tank skirt part to the outer tank skirt part is actively transmitted to the outside through this annular plate. To be exhaled.

The annular plate includes an inner projecting portion projecting inward from the support skirt and an outer projecting portion projecting outward from the support skirt, and a bottom plate of the outer tub is supported by the inner projecting portion. In addition, a cone extending downward from the side plate of the outer tub is supported by the outer overhanging portion.
Since the annular plate supports the bottom plate of the outer tub and the cone extending downward from the side plate of the outer tub, the load on the bottom plate and the side plate of the outer tub is directly received by the annular plate, and the inner tub and the outer tub. The load on the side plate and the like is transmitted to the outer tank skirt through the annular plate, and further transmitted from the outer tank skirt to the foundation.
Further, the portion of the annular plate where the bottom plate of the outer tub is supported and the portion where the cone extending from the side plate of the outer tub is supported are separated from each other and from the joint portion with the support skirt.

The inner tank skirt portion is preferably made of stainless steel, and the outer tank skirt portion is preferably made of carbon steel.
The inner tank skirt, which must be used at extremely low temperatures, is made of stainless steel that is relatively expensive and exhibits high strength even at low temperatures, while the outer tank skirt that does not lower the operating temperature is relatively inexpensive. Use carbon steel with sufficient strength. That is, optimal materials are used for the inner tank skirt and the outer tank skirt according to the temperature range to be used.

According to the first aspect of the present invention, since the plate thickness is changed at the upper and lower portions of the support skirt, the overspec, which is a drawback of the prior art, can be solved. For example, when stainless steel, which is relatively expensive, is used for the inner tank skirt portion, the material cost associated with reducing the plate thickness is greatly reduced, and many advantages can be obtained. Moreover, since the structure of the part vicinity which supports the outer tank of a support skirt is simplified, workability | operativity improves.
Also, the annular plate interposed between the inner tank skirt part and the outer tank skirt part positively radiates the cooling heat transmitted from the inner tank skirt part to the outer tank skirt part. It is possible to prevent the outer tank skirt portion from becoming cold and condensing due to cold heat.
It is possible to reduce the on-site man-hours by manufacturing the outer tank skirt in advance at the factory, making it into a block, and carrying it to the site.

  According to the invention which concerns on Claim 2, the location where the bottom plate of the outer tub in the annular plate is supported and the location where the cone extending from the side plate of the outer tub is supported are separated from each other and also from the joint portion with the support skirt. Therefore, when welding the bottom plate and the cone of the outer tank to the annular plate, and when welding the annular plate to the outer tank skirt part and the inner tank skirt part, the welded parts interfere with each other and are affected by heat. Can be avoided. Moreover, since the welding locations are separated from each other, workability when welding them is improved. Furthermore, since the structure in the vicinity of the portion supporting the outer tub of the support skirt is simplified, the workability is further improved.

  According to the third aspect of the invention, the inner tank skirt portion is made of stainless steel that is relatively expensive and exhibits high strength even at low temperatures, and the outer tank skirt portion is carbon steel having sufficient strength while being relatively inexpensive. Therefore, the cost can be reduced without difficulty while maintaining a predetermined strength.

It is the side view which carried out the cross section of a part which shows the whole embodiment of the support structure of the vertical type cryogenic storage tank concerning the present invention. It is sectional drawing which shows the principal part of the said embodiment.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows an overall sectional view of a supporting structure of a vertical cryogenic liquid storage tank in a medium-sized cryogenic storage tank of 200 to 2400 KL used for LNG, liquid oxygen, liquid nitrogen, etc., and FIG. FIG.
In FIG. 1, reference numeral 1 denotes an inner tank for storing a low-temperature liquid such as LNG, liquid oxygen, or liquid nitrogen. The inner tank 1 includes an upper end plate 2, a lower end plate 3, and side plates 4 that connect the upper and lower end plates 2, 3. Formed with. The inner tank 1 is supported on the foundation 6 through a cylindrical support skirt 5.

  The support skirt 5 is formed to have a diameter substantially the same as the diameter of the side plate 4 of the inner tank 1, and a base plate 7 at the lower end thereof is fixed to an anchor bolt (not shown) provided on the foundation 6.

  An outer tub 10 is provided outside the inner tub 1 so as to surround the inner tub 1, and a cold insulating material layer 11 is formed between the inner and outer tubs 1, 10 and filled with pearlite grains and the like.

  The outer tub 10 includes a roof 12, a side plate 13, an inverted truncated cone cone 14 connecting the lower end of the side plate 13 and the support skirt 5, a bottom plate 15 provided in the support skirt 5, the cone 14 and the bottom plate. 15 is formed of a ring-shaped outer tank annular plate 16 interposed between the two.

  A pipe (not shown) for receiving liquid and discharging BOG is connected to the upper part of the inner tank 1, and the pipe extends to the outside of the outer tank 10 through the cold insulation material layer 11. Further, a pipe (not shown) for feeding and discharging liquid is connected to the bottom of the inner tank 1, and the pipe extends to the outside of the outer tank 10 through an opening formed in the support skirt 5.

Next, a structure for supporting the outer tub 10 on the support skirt 5 will be described in detail with reference to FIG.
The support skirt 5 is divided into an upper inner tank skirt portion 18 and a lower outer tank skirt portion 19. The outer tank annular plate 16 is interposed between the inner tank skirt part 18 and the outer tank skirt part 19 which are divided into the upper and lower parts.
The outer tank annular plate 16 has a structure projecting to both the inside and the outside of the support skirt 5. That is, the outer tank annular plate 16 includes an inner projecting portion 16A projecting inward from the support skirt 5 and an outer projecting portion 16B projecting outward from the support skirt 5.

  A reinforcing ring 20 is attached to the lower part of the side plate 13 of the outer tub 10, and the outer peripheral portion of the cone 14 is attached to the reinforcing ring 20, and the inner peripheral portion of the cone 14 is connected to the outer overhanging portion 16 B of the outer tank annular plate 16. It is attached. That is, the outer peripheral portion of the cone 14 is supported by the outer overhanging portion 16B.

  The outer peripheral portion of the bottom plate 15 of the outer tub 10 is positioned below the lower end plate 3 of the inner tub 1 in consideration of the heat insulation between the bottom plate 15 and the bottom of the cold insulation material layer 11. It is attached to the inner overhanging portion 16A. That is, the inner peripheral portion of the bottom plate 15 of the outer tub 10 is supported by the inner overhanging portion 16A.

    The inner tank skirt portion 18 of the inner tank 1 and the support skirt 5 is made of a material that is resistant to cryogenic temperatures, such as SUS304, and the outer tank 10, the reinforcing ring 20, the cone 14, the outer tank skirt portion 19, and the outer tank annular plate 16 are Carbon steel that is relatively inexpensive and strong is used. Further, the plate thickness Wa of the inner tank skirt portion 18 is set to be smaller than the plate thickness Wb of the outer tank skirt portion 19. For example, the plate thickness Wa of the inner tank skirt portion 18 is set to 18 mm, and the plate thickness Wb of the outer tank skirt portion is set to 20 mm.

Next, the operation of the support structure for the vertical cryogenic liquid storage tank of the embodiment will be described.
The cryogenic liquid L is accommodated in the inner tank 1 in a state in which nitrogen gas is sealed in the cold insulation material layer 11 between the inner and outer tanks 1 and 10 until a predetermined pressure is reached for respiration against changes in the outside air temperature and the outside air pressure.
The stored low-temperature liquid L is surrounded by the cold insulation material layer 11 through the inner tank 1, and thus is kept at a sufficiently low temperature.

  Here, the support skirt 5 is divided into an upper inner tank skirt part 18 and a lower outer tank skirt part 19, and the inner tank skirt part 18 and the outer tank skirt part 19 are respectively plate thicknesses suitable for each application. And is made of different materials. That is, in this embodiment, the plate thickness Wa of the inner tank skirt portion 18 is set to be smaller than the plate thickness Wb of the outer tank skirt portion 19, and the inner tank skirt portion 18 is manufactured by SUS304. The outer tank skirt portion 19 is made of carbon steel. Thus, since the support skirt 5 is made of different materials while changing the plate thickness at the upper and lower portions, it is possible to eliminate the overspec that is a drawback of the prior art.

That is, a load of the cryogenic liquid L stored in the inner tank 1 and the inner tank is applied to the upper inner tank skirt portion 18 of the support skirt 5, and the inner tank skirts 19 are applied to the lower outer tank skirt portion 19. In addition to the load of the portion 18 and the low temperature liquid L, the load of the outer tub 10 and the cold insulation material layer 11 is also applied. Here, when the support skirt 5 is formed integrally, the thickness thereof is determined by the plate thickness Wb of the outer tank skirt portion 19 to which a large load is applied. That is, the plate thickness Wa of the inner tank skirt portion must be set to the same plate thickness Wb as the plate thickness Wb of the outer tank skirt portion 19 even if it is not necessary to set the plate thickness as thick as strength. This is clearly an over-design. In particular, when these supporting skirt portions are made of, for example, expensive stainless steel, the cost is greatly increased. However, in this embodiment, since the plate thickness Wa of the inner tank skirt portion 18 is set to be smaller than the plate thickness Wb of the outer tank skirt portion 19, excessive design can be avoided and the cost can be reduced without difficulty. It is possible to reduce the weight of the entire support structure.
In addition, SUS304, which is relatively expensive and exhibits high strength even at low temperatures, is used for the inner tank skirt portion 18 that is forced to be used at low temperatures, and is relatively inexpensive for the outer tank skirt portion 19 where the use temperature is not so low. However, carbon steel having sufficient strength is used, and also in this respect, cost can be reduced while avoiding excessive design.

The support skirt 5 is divided into an upper inner tank skirt part 18 and a lower outer tank skirt part 19, and an outer tank annular plate 16 is interposed between the inner tank skirt part 18 and the outer tank skirt part 19. The outer tub annular plate 16 supports the bottom plate 15 of the outer tub and supports the cone 14 extending downward from the side plate 13 of the outer tub. Therefore, the vicinity of the outer tub support portion of the support skirt 5 can be simplified compared to the support structure in which the outer peripheral portion of the bottom plate of the outer tub described in the prior art and the inner peripheral portion of the cone of the outer tub are concentrated in one place. At the same time, workability can be improved.
In addition, it is possible to reduce the number of man-hours at the site by manufacturing the outer tank skirt portion 19 at the factory in advance and carrying them into the block in a blocked state.

  In addition, the outer tank annular plate 16 interposed between the inner tank skirt part 18 and the outer tank skirt part 19 positively radiates the cooling heat transmitted from the inner tank skirt part 18 to the outer tank skirt part 19 to the outside. It is possible to avoid a situation in which the outer tank skirt portion 19 is condensed due to the influence of the cold heat from the inner tank skirt portion 18.

  Further, in this embodiment, the outer tank annular plate 16 is configured to include an inner overhanging portion 16A projecting inward from the support skirt 5 and an outer overhanging portion 16B projecting outward from the support skirt 5 to form an inner overhang. Since the bottom plate 15 of the outer tub is supported by the portion 16A and the cone 14 is supported by the outer overhanging portion 16B, the portion of the outer tub annular plate 16 where the bottom plate 15 of the outer tub is supported and the cone 14 of the outer tub are The portions to be supported are separated from each other and from the joint portion with the support skirt. For this reason, when the outer tank bottom plate 15 and the cone 14 are welded to the outer tank annular plate 16, respectively, and when the outer tank annular plate 16 is welded to the inner tank skirt portion 18 and the outer tank skirt portion, the welded portions are connected to each other. Can be avoided from being affected by heat and the welded portions are separated from each other, so that the workability when welding them is improved.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, this invention is not limited to this embodiment, The change of the structure of the range which does not deviate from the summary of this invention, etc. are included.
For example, in the above-described embodiment, the outer tank skirt portion 19 has a simple ring shape. However, the outer tank skirt portion is not limited to this shape, and the outer tank skirt portion is shaped to reinforce a required portion with a reinforcing member such as a rib as necessary. May be.
Moreover, in the said embodiment, although the inner tank skirt part 18 is manufactured by SUS304, it is not restricted to this, It is not limited to this, By the steel material which has required intensity | strength also in the low temperature conditions at the time of a liquid storage tank Needless to say, the outer skirt skirt portion 19 may be manufactured using the same material.

DESCRIPTION OF SYMBOLS 1 Inner tank 4 Side plate 5 Support skirt 6 Foundation 10 Outer tank 11 Cold insulating material layer 13 Side plate 14 Cone 15 Bottom plate 16 Outer tank annular plate (annular plate)
16A Inner overhanging part 16B Outer overhanging part 18 Inner tank skirt part 19 Outer tank skirt part L Cryogenic liquid

Claims (3)

In the support structure of the vertical cryogenic liquid storage tank, the inner tank for storing the cryogenic liquid is supported on the foundation via the support skirt, and the outer tank surrounding the inner tank is supported by the support skirt.
The support skirt is divided into an upper inner tank skirt part and a lower outer tank skirt part, and the plate thickness of the inner tank skirt part is set to be smaller than the plate thickness of the outer tank skirt part. And
A support structure for a vertical cryogenic liquid storage tank, wherein an annular plate serving also as a heat sink is interposed between the inner tank skirt part and the outer tank skirt part. The annular plate includes an inner overhang portion projecting inward from the support skirt, and an outer overhang portion projecting outward from the support skirt,
The vertical low temperature according to claim 1, wherein a bottom plate of the outer tub is supported by the inner overhanging portion, and a cone extending downward from a side plate of the outer tub is supported by the outer overhanging portion. Support structure for liquid storage tank. 3. The vertical cryogenic liquid storage tank support structure according to claim 1, wherein the inner tank skirt portion is made of stainless steel and the outer tank skirt portion is made of carbon steel.

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