JP5940359B2 - Construction method of vertical tank - Google Patents

Description

  The present invention relates to a method for constructing an above-ground vertical tank having an inner tub and an outer tub in which a body portion is cylindrical.

The above-ground vertical tank for storing LNG (liquefied natural gas) is a cylindrical vertical tank having an inner tank for storing LNG and an outer tank for ensuring heat insulation and airtightness. It is common.
Conventionally, in the construction work of a cylindrical body in such a vertical tank construction work, the side plates constituting the body portion are lifted one by one with a crane and arranged one turn, and the side plates are joined by welding. Later, the upper part is assembled in the same manner.

  However, in the conventional method, the side plates are arranged one round and welded together to complete one stage of the body, so that it is not possible to shift to the upper assembly work. Takes a long time and the construction period is prolonged.

  Therefore, in Patent Document 1, a side plate ring corresponding to one stage obtained by dividing the tank side plate (body portion) in the vertical direction is manufactured on the ground, and the side plate ring is lifted by a ring-shaped hanging jig and sequentially stacked on the foundation. Each time a new side plate ring is stacked on an existing side plate ring, a method of repeating the operation of joining both sides to complete the tank side plate is disclosed. And according to this construction method, it is described in Patent Document 1 that not only the construction period can be greatly shortened, but also the accuracy of the tank side plate that is finally completed can be greatly improved as compared with the conventional art.

Japanese Patent Laid-Open No. 11-062303

  However, when constructing a vertical tank having a double shell structure by the tank side plate assembly method described in Patent Document 1, the side plate ring is used until a knuckle plate used as a hanging jig is assembled in a ring shape on the ground. There is a problem that cannot be assembled. In addition, a place for assembling the knuckle plate on the ground and a place for assembling the side plates on the ground are necessary, and a large ground place is required. In addition, this method has a problem that the size of the heavy machinery increases because it is necessary to lift the knuckle plate and the side plate ring at the same time. Furthermore, in this construction method, the side plate of the outer tub cannot be assembled in a ring shape.

  The present invention has been made in view of such circumstances, and in addition to shortening the construction period and improving the construction accuracy compared to the conventional method, a construction method for a vertical tank that enables efficient placement of workers is provided. The purpose is to provide.

In order to achieve the above object, the present invention is a construction method of a vertical tank having an inner tank and an outer tank in which the body portion is cylindrical.
The inner tank side plate constituting the inner tank body and the outer tank side plate constituting the outer tank body are arranged concentrically on the same ground, and one stage of the inner tank body The inner tank side plate ring corresponding to the minute and the outer tank side plate ring corresponding to one stage of the body portion of the outer tank are assembled in parallel.

In the present invention, the following effects can be expected by arranging the inner tank side plate and the outer tank side plate concentrically at the same ground (working field) and assembling the inner tank side plate ring and the outer tank side plate ring in parallel. it can.
a. The steps that have been performed in sequence until now are completed at once, and the construction period can be shortened.
b. Assembling accuracy is improved and quality is improved, for example, the mutual interval between the inner tank side plate ring and the outer tank side plate ring can be confirmed.
c. The peripheral welding of the inner tank side plate ring (outer tank side plate ring) at the construction position and the assembly of the inner tank side plate ring (outer tank side plate ring) at the assembly site can be performed at the same time, and work personnel can be arranged efficiently. .
d. Fewer grounding sites are required.
e. The scaffold for the inner tank side plate and the scaffold for the outer tank side plate can be shared.
f. When welding the inner tank side plate, the outer tank side plate becomes a windbreak.

  Further, in the vertical tank construction method according to the present invention, the inner tank side plate ring and the outer tank side plate ring assembled at the assembly site are stacked on a foundation, respectively, so that the body portions of the inner tank and the outer tank are stacked. When constructing in parallel, after the new inner tank side plate ring is placed on the existing inner tank side plate ring and temporarily joined, the new outer tank side plate ring is immediately placed on the existing outer tank side plate ring. Alternatively, after the new outer tub side plate ring is placed on the existing outer tub side plate ring and temporarily joined, the new inner tub side plate ring is immediately attached to the existing inner tub side ring. You may mount on a tank side board ring.

In this configuration, the following effects can be expected by stacking the prefabricated inner tank side plate ring and outer tank side plate ring at the same time.
a. The circumferential welding of the inner tank side plate ring and the circumferential welding of the outer tank side plate ring can be performed in parallel.
b. When welding the inner tank side plate ring, the outer tank side plate ring becomes a wind shield.

  In the construction method of the vertical tank according to the present invention, the inner tank side plate and the outer tank side plate are arranged concentrically in the same ground assembly, and the inner tank side plate ring and the outer tank side plate ring are assembled in parallel. Not only can the construction period be shortened and the construction accuracy improved compared to the prior art, but also the work personnel can be efficiently arranged.

It is the left half elevation of a ground type vertical tank, and the right half elevation sectional view. (A)-(D) are the schematic diagrams for demonstrating the procedure of the construction method of the vertical tank which concerns on one embodiment of this invention. (E), (F) is a schematic diagram for demonstrating the procedure of the construction method of the vertical tank. (G)-(I) is a schematic diagram for demonstrating the procedure of the construction method of the same vertical tank. (J)-(M) is a schematic diagram for demonstrating the procedure of the construction method of the same vertical tank. It is the top view which showed the condition at the time of assembling an inner tank side board ring and an outer tank side board ring in the same ground assembly. (A), (B) is a schematic diagram for demonstrating the method of temporarily joining the inner tank side plate ring arrange | positioned up and down. It is a process chart of the vertical tank constructed | assembled by the construction method of the vertical tank which concerns on this Embodiment. It is a process chart of the vertical tank constructed by the conventional construction method.

  Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.

A schematic diagram of the above-ground vertical tank 10 is shown in FIG. The left half of the figure shows the appearance of the vertical tank 10, and the right half of the figure shows the inside of the vertical tank 10 with the outer tank 12 partially removed.
The vertical tank 10 has a double shell structure including an inner tank 11 in which LNG and the like are stored, and an outer tank 12 for ensuring heat insulation and airtightness.

The inner tub 11 is generally composed of an upper mirror part 13 and a lower mirror part 14, and a cylindrical body part 15 connecting the upper mirror part 13 and the lower mirror part 14, and has a so-called capsule shape. On the other hand, the outer tub 12 constructed outside the inner tub 11 closes the cylindrical body portion 16, the dome-shaped outer tub roof portion 17 that closes the upper end surface of the body portion 16, and the lower end surface of the body portion 16. It is schematically configured from a dish-shaped outer tank bottom 18.
The material of the inner tank 11 is a stainless steel plate, and the material of the outer tank 12 is a carbon steel plate, which is formed by butt welding of a plurality of steel plates.
The outer tank bottom 18 is fixed on the foundation 20 via a cylindrical outer tank skirt 19. The inner tank 11 is erected on the outer tank bottom 18 via a cylindrical inner tank skirt 21 that covers the lower mirror part 14 of the inner tank 11.

In the space between the inner tank 11 and the outer tank 12, a pipe 27 for receiving and dispensing LNG or the like is disposed. Moreover, in order to suppress heat input from the outside, a cold insulating material 28 is filled in a space between the inner tank 11 and the outer tank 12. As the cold insulation material 28, powdery pearlite is used which is obtained by heating pearlite or obsidian into a porous powder.
A watering device 29 for cooling the vertical tank 10 is disposed outside the outer tub 12.

Next, the construction procedure of the ground type vertical tank 10 will be described with reference to FIGS.
(1) After the foundation 20 made of reinforced concrete is formed at the construction position, the cylindrical outer tank skirt 19 is fixed on the foundation 20 with anchor bolts (not shown) (see FIG. 2A).
(2) The dish-shaped outer tank bottom 18 is constructed on the outer tank skirt 19, and the outer tank bottom 18 and the outer tank skirt 19 are welded and joined (see FIG. 2B).

(3) An inner tank side plate 25 constituting the inner tank skirt 21 and an outer tank side plate 26 constituting the trunk portion 16 of the outer tank 12 are arranged concentrically on the same ground, and the first stage skirt ring 31 and the first-stage outer tank side plate ring 41 are assembled in parallel. Then, the vertical welding between the inner tank side plates 25 and the vertical welding between the outer tank side plates 26 are completed almost at the same time.
(4) After the first stage skirt ring 31 is lifted by the lifting jig 50 and placed on the outer tank bottom 18, the first stage outer tank side plate ring 41 is immediately lifted by the hanging jig 50 and the outer tank bottom. 18 (see FIG. 2C). Then, the lower end of the skirt ring 31 and the lower end of the outer tank side plate ring 41 are welded to the outer tank bottom 18 respectively.

(5) While performing the operation (4) at the construction position, the second-stage skirt ring 32 and the second-stage outer tank side plate ring 42 are installed in the same manner as in (3) at the assembly site. assemble.
(6) The second stage skirt ring 32 is lifted by the lifting jig 50, placed on the first stage skirt ring 31 and temporarily joined, and then the second stage outer tank side plate ring 42 is immediately suspended. It is lifted at 50 and placed on the first-stage outer tank side plate ring 41 and temporarily joined (see FIG. 2D). Then, circumferential welding of the upper end of the first stage skirt ring 31 and the lower end of the second stage skirt ring 32, the upper end of the first stage outer tank side plate ring 41, and the second stage outer tank side plate ring 42. Peripheral welding of the lower end of the is performed in parallel.

(7) In the building site, the lower end plate 36 is arranged in a ring shape using the gantry 51, and the lower end plate 37 is attached to the bottom surface (see FIG. 3E). And after welding a junction part and assembling the lower mirror part 14, the nondestructive inspection of the lower mirror part 14 is implemented.
(8) The lower mirror part 14 is suspended by the suspension jig 50 and the lower mirror part 14 is inserted into the inner tank skirt 21 (see FIG. 3F). Then, the peripheral part of the lower mirror part 14 is placed on the second stage skirt ring 32, and the peripheral part of the lower mirror part 14 and the upper end part of the second stage skirt ring 32 are welded.

(9) While performing the operation (8) at the construction position, the first stage inner tank side plate ring 33 and the third stage outer tank side plate ring 43 constituting the trunk portion 15 are installed at the assembly site. Assemble by the same method as (3).
(10) The first-stage inner tank side plate ring 33 is lifted by the lifting jig 50, placed on the peripheral edge of the lower mirror part 14 and temporarily joined, and then the third-stage outer tank side plate ring 43 is immediately suspended. It is lifted by the jig 50 and placed on the second stage outer tank side plate ring 42 to be temporarily joined (see FIG. 4G). And the circumference welding of the lower end part of the 1st step | paragraph inner tank side plate ring 33 and the peripheral part of the lower mirror part 14, the lower end part of the 3rd step | paragraph outer tank side plate ring 43, and the 2nd step | paragraph of the outer tank side plate ring 42 Peripheral welding of the upper end is performed in parallel.
(11) Thereafter, the second and third inner tank side plate rings 34 and 35 and the fourth and fifth stage outer tank side plate rings 44 and 45 are assembled and stacked in the same manner (FIG. 4 ( H) and (I)).

(12) At the building site, the upper end plate 38 is arranged in a ring shape, and the upper end plate 39 is attached to the top surface (see FIG. 5J). And after welding the junction part and assembling the upper mirror part 13, the non-destructive inspection of the upper mirror part 13 is implemented.
(13) The upper mirror part 13 is hung with the lifting jig 50, the peripheral part of the upper mirror part 13 is placed on the third-stage inner tank side plate ring 35 and temporarily joined, and then the peripheral part of the upper mirror part 13 And the upper end of the third-stage inner tank side plate ring 35 are welded (see FIG. 5K).

(14) In the assembly site, the outer tank side plates 26 are arranged in a ring shape, the sixth stage outer tank side plate ring 46 is assembled, and the outer tank side plates 26 are welded vertically (see FIG. 5L). ). And after assembling the outer tank roof part 17, the outer tank roof part 17 is mounted on the 6th-stage outer tank side board ring 46, the peripheral part of the outer tank roof part 17, and the 6th stage outer tank side board The upper end of the ring 46 is welded.
(15) A pipe 27 is disposed in the space between the inner tank 11 and the outer tank 12. Then, the sixth-stage outer tub side plate ring 46 and the outer tub roof portion 17 are suspended by the hanging jig 50, and the sixth-stage outer tub side plate ring 46 is placed on the five-step outer tub side plate ring 45. Then, after the temporary joining, circumferential welding of the lower end of the sixth stage outer tank side plate ring 46 and the upper end of the fifth stage outer tank side plate ring 45 is performed (see FIG. 5M).

Here, the assembling work of the inner tank side plate ring 30 and the outer tank side plate ring 40 which is performed at the assembly site will be described. In addition, although the case where the inner tank side plate 25 and the outer tank side plate 26 constitute 1/4 of the inner tank side plate ring 30 and the outer tank side plate ring 40, respectively, will be described below, the present invention is not limited thereto.
As shown in FIG. 6, the inner tank side plate 25 divided into four parts in plan view and the outer tank side plate 26 divided into four parts in plan view of the outer tank side plate ring 40 are the same ground. It arranges concentrically with. In that case, the inner tank side board 25 is arrange | positioned inside the outer tank side board 26 (center side of a virtual circle). The scaffold 52 is constructed along the inner tank side plate 25 on the inner side and the outer side of the inner tank side plate 25, and the scaffold 52 is constructed along the outer tank side plate 26 on the outer side of the outer tank side plate 26.
By doing in this way, not only can the assembly of the inner tank side plate ring 30 and the outer tank side plate ring 40 be performed in parallel work, but it is also possible to share the scaffold for the inner tank side plate and the scaffold for the outer tank side plate. it can.

FIG. 7 shows a method of temporarily joining the inner tank side plate rings 30 arranged vertically.
As shown in FIG. 7A, one side of the projecting member 60 made of a rectangular plate is T-welded to the upper end portion and the lower end portion on the inner peripheral surface side of the inner tank side plate ring 30. A hole 60 a for inserting a conical wedge (not shown) is formed in the center of the protruding member 60.
On the other hand, the connecting member 61 that connects the inner tub side plate ring 30 and the inner tub side plate ring 30 includes a strip plate 63 in which rectangular cutouts 63a that open in the short direction are formed on both sides in the longitudinal direction, and a strip plate And a pair of abutment portions 62 that seal the opening of each notch 63a. Each contact portion 62 is provided with a slit 62a into which the protruding member 60 is inserted.

As shown in FIG. 7B, a protruding member 60 protruding from the lower end portion of the upper inner tank side plate ring 30 is inserted into the slit 62a provided in one abutting portion 62 of the connecting member 61 and connected. The protruding member 60 protruding from the upper end of the lower inner tank side plate ring 30 is inserted into the slit 62 a provided in the other contact portion 62 of the member 61, and the pair of contact portions 62 are connected to the inner tank side plate ring 30. It is made to contact | abut to the internal peripheral surface. And the inner tank side board ring 30 arrange | positioned up and down is temporarily joined by inserting a wedge in the hole 60a of the projection member 60 which protrudes from each contact part 62, respectively.
In addition, the method of temporarily joining the outer tank side plate ring 40 arrange | positioned up and down is the same.

  Finally, FIG. 8 shows a process chart (example) when constructing a vertical tank by the construction method of the vertical tank according to the present embodiment, and a process chart when constructing a vertical tank by the conventional construction method (comparison). An example) is shown in FIG. In the embodiment, the idle time hardly occurs between the operations of the inner tank side plate ring and the outer tank side plate ring, but in the comparative example, the idle time of about 10 days occurs between the preceding side plate ring operations. As a result, it can be seen that the working period is shortened by about one month in the example compared to the comparative example. In addition, if the number of steps of the side plate ring is 7 or more, the construction period difference between the example and the comparative example is further widened.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the configuration described in the above-described embodiment, and is within the scope of matters described in the claims. Other possible embodiments and modifications are also included. For example, in the said embodiment, although the inner tank side plate ring is piled up before the outer tank side plate ring, the reverse may be sufficient. Moreover, in the said embodiment, although the inner tank side plate ring and the outer tank side plate ring are piled up alternately, the inner tank side plate ring and the outer tank are hung together with a hanging jig. The side plate rings may be stacked simultaneously.

10: Vertical tank, 11: Inner tank, 12: Outer tank, 13: Upper mirror part, 14: Lower mirror part, 15, 16: Body part, 17: Outer tank roof part, 18: Outer tank bottom part, 19: Outer tank skirt, 20: Foundation, 21: Inner tank skirt, 25: Inner tank side plate, 26: Outer tank side plate, 27: Piping, 28: Cooling material, 29: Sprinkler, 30, 33, 34, 35: Inner tank Side plate ring, 31, 32: Skirt ring, 36: Lower end plate, 37: Lower end plate, 38: Upper end plate, 39: Upper end plate, 40, 41, 42, 43, 44, 45, 46: Outer tank Side plate ring, 50: suspension jig, 51: platform, 52: scaffolding, 60: projection member, 60a: hole, 61: connecting member, 62: abutting portion, 62a: slit, 63: strip-shaped plate, 63a: notch

Claims (3)

In the construction method of the vertical tank having the inner tank and the outer tank whose body part is cylindrical,
The inner tank side plate constituting the inner tank body and the outer tank side plate constituting the outer tank body are arranged concentrically on the same ground, and one stage of the inner tank body A vertical tank construction method comprising assembling in parallel an inner tank side plate ring corresponding to a minute and an outer tank side plate ring corresponding to one stage of the trunk of the outer tank.   The vertical tank construction method according to claim 1, wherein the inner tank side plate ring and the outer tank side plate ring assembled at the assembly site are stacked on a foundation, respectively, and the inner tank and the outer tank body are arranged in parallel. Then, after the new inner tank side plate ring is placed on the existing inner tank side plate ring and temporarily joined, the new outer tank side plate ring is immediately placed on the existing outer tank side plate ring. A construction method of a vertical tank, characterized by being placed.   The vertical tank construction method according to claim 1, wherein the inner tank side plate ring and the outer tank side plate ring assembled at the assembly site are stacked on a foundation, respectively, and the inner tank and the outer tank body are arranged in parallel. When the new outer tank side plate ring is placed on the existing outer tank side plate ring and temporarily joined, the new inner tank side plate ring is immediately placed on the existing inner tank side plate ring. A construction method of a vertical tank, characterized by being placed.

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