Roll-type storage tank unfolding installation construction method and roll-type storage tank

Abstract

The invention discloses a construction method for unfolding and installing a package type storage tank, which comprises the following steps of: firstly, paving, welding and installing a tank bottom on a foundation, gradually unfolding a drum-shaped tank wall on the tank bottom, performing positioned welding with a bottom plate in the unfolding process, welding a positioning fixture on the outer side of the bottom plate, adjusting a wall plate to a proper radian by utilizing the elasticity of the wall plate, a steel wire rope chain block and the like, and fixing the wall plate on the bottom plate; redundant parts of vertical butt welding seams of the wallboards are cut off according to a drawing, then the width of the vertical welding seams at the connecting positions of the wallboards, the radian of the wallboards, overall vertical positioning of the wallboards and the like are adjusted through a welding seam adjusting clamp and other conventional clamps, and assembly welding of the wall boards of the tank barrel is completed. The welding quality of the tank wall can be guaranteed, aloft work is reduced, the construction period of the tank wall is shortened, the construction cost is reduced, the construction efficiency is improved, and the problems of tank wall deformation and safety in the installation process are effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of large storage tank construction, in particular to a coiled storage tank unfolding installation construction method and a coiled storage tank. BACKGROUND

[0002] Traditional storage tank construction is to cut steel plates on the construction site, roll them into shape by a coiling machine, and then use the "normal installation method" or "inverted installation method" to connect and weld them into a tank wall piece by piece through on-site welding. This method not only consumes time and effort, but also is limited by weather conditions, and is prone to problems such as uneven welding quality and low work efficiency. With the development of technology and the improvement of industrialization level, the industry has higher requirements for construction efficiency and quality control. In this context, the wall plate is integrally welded into a tank wall on the ground, and the coiled and formed tank wall is transported to the storage tank foundation for on-site unfolding installation process, which becomes a new idea to solve the traditional construction problems. The tank wall is integrally precast and coiled into a cylinder and then transported to the construction site, and how to unfold the tank wall at the construction site is a major difficulty. SUMMARY

[0003] The purpose of the present application is to provide a coiled storage tank unfolding installation construction method to improve the construction efficiency of the tank wall.

[0004] To achieve the above purpose, according to one aspect of the present application, a coiled storage tank unfolding installation construction method is provided, comprising: Step one, install and fix the storage tank bottom plate on the foundation, and mark the wall plate reference line on the bottom plate and arrange the positioning blocks at intervals; Step two, reinforce the tank wall coiled cylinder which is precast and fixed on the center frame; the reinforcement includes setting an internal support structure inside the center frame, and setting at least one longitudinal reinforcing structure on the outside of the tank wall coiled cylinder; Step three, hoist the reinforced tank wall coiled cylinder to above the bottom plate and keep it in a vertical state; remove the initial constraint of the tank wall coiled cylinder, position and connect the starting end of the outermost wall plate with the pre-set starting position on the bottom plate, and pull a diagonal brace at the top of the tank wall coiled cylinder; Step four, use a crane to move the tank wall coiled cylinder clockwise or counterclockwise along the foundation, and use a drop chain to apply a pulling force opposite to the unfolding direction of the tank wall coiled cylinder, so that the tank wall coiled cylinder is gradually unfolded; during the unfolding process, the unfolded tank wall segments are adjusted in arc at intervals, and the lower edge is positioned and connected with the bottom plate; Step five, when the tank wall coiled cylinder is unfolded to the last circle, separate the center frame from the tank wall coiled cylinder, and cut off the reserved excess at the butt joint of the tank wall coiled cylinder; Step six, correct the overall shape of the completely unfolded tank wall, and weld the vertical seams between adjacent wall plates.

[0005] In a preferred embodiment, in step two, the internal support structure includes multiple support steel pipes inserted into and fixed to the central frame along the length of the tank wall drum. The bottom of the support steel pipes is provided with a limiting block to prevent the tank wall drum from axially dislodging, and the top of the support steel pipes is provided with lifting lugs for connecting hoisting equipment.

[0006] In a preferred embodiment, the number of supporting steel pipes is four, which are evenly arranged around the circumference of the central frame.

[0007] In a preferred embodiment, in step two, the longitudinal reinforcing structure is an I-beam, which is installed near the pre-set weld seam on the outer side of the tank wall roll.

[0008] As a preferred embodiment, three anchor points are welded to the inner side of the tank wall at the top, middle, and bottom, and fixed with chain hoists; three lifting lugs are welded to the I-beams on the outer side of the tank wall as anchor points for the chain hoists and fixed with chain hoists.

[0009] In a preferred embodiment, in step three, when the diagonal bracing is installed on the top of the tank wall roll, an anchor point is welded on the inner and outer sides of the top of the tank wall roll, and the diagonal bracing is installed by steel wire rope. The outer diagonal bracing is connected to the ground anchor point, and the inner diagonal bracing is connected to the anchor point welded on the bottom plate.

[0010] In a preferred embodiment, in step four, the chain hoist on the inside of the tank wall is replaced with a new anchor point every time the tank is extended a certain distance; every time the tank is extended a certain distance, anchor points are welded on the inner and outer sides of the top of the tank wall and steel wire ropes are pulled; this process is repeated until the tank wall is fully extended.

[0011] In a preferred embodiment, during step four, when the tank wall roll is unrolled, a clamp is welded at a predetermined interval on the bottom plate inside the tank wall and a wedge is driven in to adjust the curvature of the tank wall and perform a positioning spot weld.

[0012] In a preferred embodiment, in step five, the separated central frame is repositioned and fixed at the center of the storage tank as a temporary support column for the subsequent installation of the tank top structure.

[0013] According to another aspect of the present invention, a roll-type storage tank is provided, wherein the tank wall is constructed using the method described above.

[0014] Compared with the prior art, the beneficial effects of this invention patent are as follows: Compared to traditional methods of inverted and upright installation of tank walls, this invention offers a novel method for tank wall construction. All tank wall panels are assembled into a single unit in the factory, then rolled onto a circular steel frame and transported to the construction site. At the construction site, the rolled tank wall is simply unrolled using lifting equipment, tooling, and a chain hoist; on-site panel assembly is unnecessary. This invention ensures high-quality welding, reduces high-altitude work, shortens the construction cycle, lowers construction costs, and improves efficiency. It can reduce the installation time of similar tank walls to approximately two-thirds of other traditional methods and effectively solves the problems of tank wall deformation and safety during installation. Detailed Implementation

[0015] The basic concept of this invention is to first lay and weld the tank bottom on the foundation, then gradually unfold the cylindrical tank wall on the tank bottom. During the unfolding process, it is positioned and welded to the bottom plate. Positioning clamps need to be welded to the outside of the bottom plate. The elasticity of the wall panel and steel wire rope chain hoists are used to adjust the wall panel to a suitable curvature. The excess part of the vertical butt weld of the wall panel is removed according to the drawings. Then, weld adjustment clamps and other conventional clamps are used to adjust the width of the vertical weld at the wall panel connection, the curvature of the wall panel, and the overall vertical positioning of the wall panel, etc., to complete the assembly and welding of the tank body wall panels.

[0016] Based on the above embodiments, a typical embodiment of the present invention provides a method for the unfolding and installation of roll-up storage tanks. Taking a chemical complex project in the Baltic Sea region of Russia undertaken by China National Chemical Engineering Second Construction Co., Ltd. as an example, the project includes six non-standard storage tanks. The tank walls are integrally spliced ​​and welded in the factory, then rolled up onto a circular frame and transported to the construction site. During construction, the rolled-up tank walls are unfolded and installed onto the base plate. The six storage tanks are: two 3000m³ stainless steel tanks with a diameter of 18.98m and a height of 11.92m; two 1000m³ stainless steel tanks; one 1000m³ carbon steel tank with a diameter of 10.43m and a height of 11.92m; and one 500m³ carbon steel tank with a diameter of 8.53m and a height of 8.94m. The walls of stainless steel storage tanks are 8mm thick, while those of carbon steel storage tanks are 7mm thick. Since the walls are relatively thin, preventing deformation of the tank walls during the unfolding process is a major challenge. The tank walls arrive in a rolled-up state, which also presents a challenge in unfolding them.

[0017] This implementation method mainly includes base plate installation and fixing, tank wall roll fixing, tank wall hoisting, starting point positioning, tank wall unfolding, center column disassembly and tank wall docking.

[0018] Floor installation and anchoring The tank bottom plate is installed and fixed on the basis, and the wall panel baseline is marked on the bottom plate and positioning blocks are arranged at intervals.

[0019] The tank bottom plate consists of a middle plate and edge plates. The edge plates are laid first. Considering the shrinkage of the edge plate welds, the bevel gap is strictly controlled when assembling the butt welds of the edge plates, ensuring that the gap is larger on the inside and smaller on the outside. Anti-deformation measures are taken before welding, and two gantry blocks are installed at both ends of the edge plates. The butt welds of the edge plates are welded first, with the welds extending 300mm from the outside. Only after passing the inspection can the next step of construction be carried out.

[0020] When laying the intermediate panels, use a crane to place the base plates on the foundation according to the overlapping sequence shown in the drawings. After the intermediate panels are laid, use clamps to press and secure the joints according to the welding sequence. If the entire continuous seam cannot be assembled on the same day, the remaining un-tack-welded seams must be reinforced with connecting plates to prevent changes in the weld gap caused by thermal expansion and contraction.

[0021] The overlap joint between the middle plate and the edge plate is reserved as an expansion joint when welding the bottom plate. This reserved joint will be welded after the fillet weld between the tank wall and the bottom plate is completed.

[0022] Base plate fixing: Before installing the tank wall panels, weld the tooling clamps 3 to the edge of the base plate 1 to fix the base plate 1 to the foundation 2, preventing the wall panels from dragging the base plate during hoisting. Mark the wall panel baseline on the tank bottom plate and arrange the positioning blocks 4. The distance between the two positioning blocks 4 should be controlled within the range of 600~700mm.

[0023] Tank wall reel anchoring The prefabricated tank wall roll fixed on the central frame is reinforced; the reinforcement includes setting an internal support structure inside the central frame and setting at least one longitudinal reinforcement structure on the outside of the tank wall roll.

[0024] The internal support structure includes multiple support steel pipes inserted into and fixed to the central frame along the length of the tank wall drum. The bottom of each support steel pipe is equipped with a limiting block to prevent the tank wall drum from axially dislodging, and the top of the support steel pipe is equipped with lifting lugs for connecting lifting equipment. The longitudinal reinforcement structure is an I-beam, located near the pre-set weld joint on the outer side of the tank wall drum.

[0025] The tank wall arrives in a rolled shape, with a central frame made of angle steel. The central frame is welded to one edge of the rolled tank wall. Therefore, before hoisting, the tank wall is pre-fabricated to securely fix it to the central frame and enhance its structural stability. Four DN150 support steel pipes are inserted into the central frame as the main load-bearing supports during hoisting. The support steel pipes are welded to the central frame, and 20mm thick steel plates are welded to the bottom and top of each support steel pipe. Lifting lugs are welded to the top of each support steel pipe's steel plate, and limiting blocks are welded to the bottom of each support steel pipe's steel plate to prevent the rolled tank wall from falling off the central frame during hoisting.

[0026] Because the tank walls are relatively thin, in order to prevent severe deformation of the tank walls during the unfolding process, an I18 I-beam is welded on the outside of the tank wall near the joint weld as a longitudinal reinforcement structure using a discontinuous welding method. At the same time, three lifting lugs are welded on the I-beam as anchor points for the chain hoist, with evenly distributed positions, as a safety measure when the tank wall is unpacked.

[0027] When the tank wall arrives, it is rolled up on the central frame without stress relief. During the unwinding process, it will automatically unwind to a certain extent like a spring, which will cause difficulties in subsequent hoisting and also pose a huge safety hazard. To prevent this from happening, anchor points are welded at the top, middle and bottom of the inner side of the tank wall and fixed with chain hoists; three lifting lugs are welded on the I-beams on the outer side of the tank wall as anchor points for the chain hoists and fixed with chain hoists.

[0028] Tank wall hoisting Using a 130-ton crawler crane as the main crane and a 50-ton truck crane as the auxiliary crane, the tank wall roll was first lifted from a horizontal position to a vertical position using a lifting method.

[0029] The main crane lifts the tank wall roll up close to the bottom plate of the storage tank, cuts open the fixing points welded on the factory packaging, and simultaneously loosens the three chain hoists that were pre-installed on the outside. After loosening to a certain extent, an anchor point is welded on the loosened inside of the tank wall. The bottom chain hoist of the three chain hoists is then loosened and connected to this anchor point. At this point, the remaining two chain hoists on the outside are completely removed.

[0030] Starting point positioning Draw the starting point of the tank wall on the bottom plate of the storage tank in advance, and also draw the corresponding starting point on the tank wall.

[0031] Use an auxiliary crane to lift the loosened outer wall panel slightly so that it is removed from the limiting block under the central frame. Then, locate the starting point for the connection between the tank wall and the bottom plate. Weld a temporary steel plate at the starting point, align it, and spot weld it in place. At the same time, weld an anchor point on the inside and outside of the top of the tank wall, and connect and install diagonal braces with steel wire ropes. The outer side is reliably connected to the ground anchor point, and the inner side is connected to the anchor point on the bottom plate. Connect the bottom of the steel wire rope with turnbuckles to facilitate the adjustment of the steel wire rope length.

[0032] Tank wall unrolling After the starting point is located, a chain hoist anchor point is welded within a height of 0.5~1m on the outside of the tank wall drum. According to the design drawings, the tank wall is laid out clockwise along the foundation, and the chain hoist is pulled in the opposite direction. While the chain hoist is being pulled, the main crane lifts the tank wall drum and moves it slowly clockwise along the foundation, while slowly releasing the chain hoist set on the lower inside of the tank wall.

[0033] After unfolding a certain distance, the main crane stops moving. Anchor points are welded on both the inner and outer sides of the tank wall near the top, and secured with wire ropes to prevent the tank wall from tilting. A new anchor point is welded on the lower inner side of the tank wall near the un-unfolded area, and a chain hoist is installed to prevent the tank wall from spreading under stress. A new anchor point is welded on the outer side of the tank wall drum at a height of 0.5 to 1m for connecting the chain hoist.

[0034] During the tank wall unfolding process, a clamp is welded at certain intervals on the bottom plate inside the tank wall as needed, wedges are driven in, the curvature of the tank wall is adjusted, and positioning spot welding is performed.

[0035] Repeat the above steps, replacing the inner chain hoist with a new anchor point every time the tank is extended a certain distance; weld anchor points on both the inner and outer sides of the top of the tank wall every time the tank is extended a certain distance, and pull steel wire ropes; repeat this process until the tank wall is fully extended.

[0036] Center column disassembly When the tank wall roll is unrolled to the last ring of the wall panel, the three chain hoists that were pre-installed on the inner wall are released simultaneously. Then, the connection point between the central frame and the tank wall is cut, the central frame is hoisted to the center of the tank, adjusted and fixed, and used as the central support for the construction of the tank top plate. The last ring of the tank wall is then adjusted into place.

[0037] Tank wall butting After the tank wall is unfolded, scaffolding work platforms are erected on both sides of the joint between the wall panels.

[0038] The curvature of the entire tank wall is corrected by adjusting the internal and external steel wire ropes. The circumference of the tank is measured according to the dimensions on the drawings. After the quality department checks and confirms the measurement, the reserved allowance at the interface of the tank wall is cut off, and staggered joints are formed between each plate.

[0039] On both sides of the butt joint on the inner and outer sides of the wall panel, weld vertical weld positioning plates from top to bottom, one plate approximately every 500mm. Insert positioning wedges between the positioning plates and the wall panel to ensure the wall panel is accurately positioned for installation. Then, fix vertical weld adjustment plates between the corresponding two vertical weld positioning plates at the wall panel connection point to adjust the width of the vertical weld and the curvature of the wall panel. After adjustment and confirmation that everything is correct, weld the vertical welds from top to bottom. Once the inspection is passed, the wall panel installation and construction are complete.

[0040] Before welding, the verticality of the tank wall should be measured and positioned to avoid the inability to adjust after welding.

[0041] The scope of protection claimed by this invention is not limited to the specific embodiments described above. For those skilled in the art, this invention can have various modifications and alterations. Any modifications, improvements, and equivalent substitutions made within the concept and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for installing a roll-out storage tank, characterized by, The method comprises the following steps: Step 1: install and fix the tank bottom plate on the foundation, and mark the wall plate reference line on the bottom plate and arrange the positioning blocks at intervals; Step 2: reinforce the tank wall coil on the center frame, which comprises arranging an internal support structure inside the center frame and arranging at least one longitudinal reinforcing structure outside the tank wall coil; Step 3: hoist the reinforced tank wall coil to above the bottom plate and keep it in a vertical state, remove the initial constraint of the tank wall coil, position and connect the starting end of the outermost circle of wall plates with the preset starting position on the bottom plate, and pull a diagonal brace at the top of the tank wall coil; Step 4: move the tank wall coil along the foundation clockwise or counterclockwise by using a crane, exert a traction force opposite to the unfolding direction of the tank wall coil by using a chain fall, and gradually unfold the tank wall coil; during the unfolding process, adjust the curvature of the unfolded tank wall segment at intervals and position and connect the lower edge of the tank wall segment with the bottom plate; Step 5: when the tank wall coil is unfolded to the last circle, separate the center frame from the tank wall coil, and cut off the reserved excess at the butt joint of the tank wall coil; Step 6: correct the overall shape of the completely unfolded tank wall, and weld the vertical weld seams between adjacent wall plates.

2. The method according to claim 1, wherein: In step 2, the internal support structure comprises a plurality of support steel pipes inserted into the center frame along the length direction of the tank wall coil and fixed, the bottom of the support steel pipe is provided with a limiting block for preventing the tank wall coil from being axially separated, and the top of the support steel pipe is provided with a lifting lug for connecting a hoisting device.

3. The method according to claim 2, wherein: The number of support steel pipes is four, which are arranged uniformly in the circumferential direction of the center frame.

4. The method according to claim 1, 2 or 3, wherein: In step 2, the longitudinal reinforcing structure is an I-beam arranged near the preset group welding seam outside the tank wall coil.

5. The method of claim 4, wherein: Anchors are welded on the inner side of the tank wall at three positions, i.e., upper, middle and lower positions, and are fixed by using a chain fall; three anchors are welded on the I-beam outside the tank wall as anchoring points of the chain fall and are fixed by using a chain fall.

6. The method according to claim 5, wherein: In step 3, when the diagonal brace is pulled at the top of the tank wall coil, an anchor point is welded on the inner and outer sides of the top of the tank wall coil respectively, and a diagonal brace is pulled by using a steel wire rope; the outer side of the diagonal brace is connected with a ground anchor point, and the inner side of the diagonal brace is connected with an anchor point welded on the bottom plate.

7. The method according to claim 5 or 6, wherein: In step 4, a new anchor point is replaced every time the tank wall is unfolded by a certain distance; an anchor point is welded on the inner and outer sides of the top of the tank wall every time the tank wall is unfolded by a certain distance, and a steel wire rope is pulled; the above steps are repeated until the tank wall is completely unfolded.

8. The method according to claim 7, wherein: In step 4, an anchor point is welded on the inner side of the bottom plate of the tank wall at intervals and a wedge is driven in every predetermined distance during the unfolding process of the tank wall coil, so as to adjust the curvature of the tank wall and position and spot weld.

9. The method according to claim 1 or 8, wherein: In step 5, the separated center frame is repositioned and fixed in the center of the storage tank as a temporary support column for subsequent installation of the tank top structure.

10. A roll pack storage tank characterized by, The tank wall is built by using the method according to any one of claims 1 to 9.