Large storage tank vault dismantling process

Abstract

The invention discloses a large storage tank vault dismantling process which comprises the following process steps: step 1, firstly, cutting a reticulated shell into an octagon, then manufacturing reinforcing rods, enabling the reinforcing rods to be hinged to chord members of the reticulated shell, ensuring that the hinged parts can move, fully welding contact parts, and performing coloring detection to be qualified after welding is completed; the length of the component is set out on site, and then an auxiliary supporting system is arranged. In order to solve the problem of transformation of an existing large storage tank, the stability of the storage tank is utilized, a reticulated shell supporting system is built, the dismantling sequence is optimized, a storage tank reticulated shell is divided into dismantling areas finely, the dismantling area of the storage tank reticulated shell is divided, the reticulated shell is divided into a middle area, a walkway plate area, a secondary outer ring area and an outer ring area, and dismantling is conducted in sequence according to the sequence. The dismounting work of the large storage tank vault reticulated shell is efficiently and safely completed in a high-quality mode, original floating discs, wall plates and bottom plate parts reserved by the storage tank are not damaged, the construction quality and the construction period are guaranteed, and the dismounting cost is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of vault removal, in particular to a process for removing the vault of a large storage tank. Background Art

[0002] In order to facilitate the storage of refined oil, it is planned to renovate the existing 50,000m3 storage tanks. The main renovation content is to transform the existing internal floating roof fixed arch storage tanks into external floating roof storage tanks, and to change the arch storage tanks originally used to store diesel and gasoline into external floating plate storage tanks for storing crude oil. The existing internal floating roof fixed arch storage tanks in my country are mainly composed of bottom plate, wall plate, fixed inner floating plate, fixed arch lattice shell and skin. This renovation mainly retains the existing floating plate, wall plate and bottom plate of the storage tank, and removes the fixed arch lattice shell of the storage tank for protection;

[0003] At present, there are no 50,000m3 tank vault renovation and demolition projects in China that can be used as reference. If conventional practices are adopted, scaffolding needs to be erected all over the place first. Since the weight of the tank grid shell is about 106.7 tons, the tank wall is 19.8m high and 60m in diameter, and the maximum height of the grid shell top is 29.8m, at least 35,000 meters of scaffolding and 16,000 fasteners are required. It takes about 80 days to erect and dismantle the full-length scaffolding, which will result in extended construction period, increased labor consumption, and waste of materials. At the same time, the renovation project has a large amount of high-altitude operations and is highly dangerous. During the demolition process, the grid shell is prone to collapse due to imbalance in bearing capacity, causing safety accidents.

[0004] Therefore, we proposed a large tank vault removal process. Summary of the invention

[0005] The purpose of the present invention is to provide a large storage tank vault removal process, which solves the problems raised in the background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a large storage tank vault removal process, comprising the following process steps:

[0007] Step 1: First, the grid shell is cut into an octagon, and then the reinforcement rod is made. The reinforcement rod and the grid shell chord are hinged to ensure that the hinged part can move and the contact part is fully welded. After the welding is completed, it is qualified by coloring test. The length of the component is set out on site, and then the auxiliary support system is set to support the original grid shell. The layout method is to use the center line of the grid shell as the axis, and the rotation angle is 18 degrees along the periphery. Each grid shell is set with 20 auxiliary support systems;

[0008] Step 2: Make two sets of movable working platforms. The length and width of the platform are 1X6m. The platform plate is made of 5mm patterned steel plate or steel plate. Railings are set around to ensure the safety of construction operations. There are no more than 2 workers on each platform, and no more than 10 workers on each tank. There are 6 lifting points on the platform. The movable platform is lifted to the lattice shell removal position by a crane, and the two channel steels at the bottom of the platform are clamped on the chord of the lattice shell, and fixed with the chord by a movable slider. The steel plate is made of the dismantled skin. Two movable platforms are made according to different areas. Different movable platforms are installed according to different areas during construction to meet the needs of safe operation of personnel;

[0009] Step 3: Divide the tank grid shell into demolition areas. Divide the tank grid shell into middle area, walkway plate area, sub-outer ring area, outer ring area, and mark the demolition size. Use a crane to lift each piece away, and perform gas cutting and demolition in sequence to complete all demolition work.

[0010] As a preferred embodiment of the present invention, a fire blanket and a steel springboard are laid in sequence on the inner floating plate at the bottom of the storage tank before dismantling to prevent the cut waste from damaging the floating plate.

[0011] As a preferred embodiment of the present invention, in step three, the patterned steel plate is appropriately bent according to the curvature of the lattice shell arch, and an anti-slip strip is provided on the platform plate.

[0012] As a preferred embodiment of the present invention, in step 2, the height of the railing is 1200 mm and the weight does not exceed 300 kg.

[0013] As a preferred embodiment of the present invention, the support system in step 1 utilizes the original cone plate and the corbel to form a diagonal support structure of the tripod.

[0014] As a preferred embodiment of the present invention, the original grid shell needs to be inspected twice before demolition, before reinforcement and before operation, and the inspection methods are visual and knocking.

[0015] As a preferred embodiment of the present invention, the reinforcement rod in step one is made of channel steel and unequal angle steels that are removed later.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention solves the difficult problem of existing large-scale storage tank transformation, utilizes the stability of the storage tank itself, builds a lattice shell support system, optimizes the demolition sequence, divides the storage tank lattice shell into demolition areas, divides the demolition of the storage tank lattice shell into areas, divides the lattice shell into an intermediate area, a walkway plate area, a secondary outer ring area, and an outer ring area, and demolishes them in sequence, efficiently, safely, and with high quality completes the demolition of the large-scale storage tank vault lattice shell, the original floating plate, wall plate and bottom plate retained in the storage tank are not damaged, the construction quality and construction period are guaranteed, the demolition cost is greatly reduced, and it has significant social and economic benefits and has promotion and reference value. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0019] Figure 1 A schematic diagram of the division of the lattice shell demolition area in a large storage tank vault demolition process of the present invention;

[0020] Figure 2 A diagram of a temporary movable platform for a large storage tank vault removal process according to the present invention;

[0021] Figure 3 A temporary movable platform structure diagram showing the manufacturing and installation of a temporary movable platform for a large tank vault removal process according to the present invention;

[0022] Figure 4 A schematic diagram of a lattice shell structure of a large storage tank vault removal process according to the present invention;

[0023] Figure 5 A schematic diagram of a lattice shell auxiliary support structure for a large storage tank vault removal process according to the present invention;

[0024] Figure 6 A schematic diagram of the central area demolition sequence of a large storage tank vault demolition process according to the present invention;

[0025] Figure 7 A schematic diagram of the removal sequence of the walkway plate area in a large tank vault removal process of the present invention;

[0026] Figure 8 It is a schematic diagram of the sequence of removing the secondary outer ring of a large storage tank vault removal process of the present invention;

[0027] Fig. 9 It is a schematic diagram of the outer ring removal sequence of a large storage tank vault removal process of the present invention. DETAILED DESCRIPTION

[0028] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0029] Example

[0030] A large tank vault removal process

[0031] This process is based on the stability advantages of the storage tank itself and the actual situation on site. It uses the original stress conditions of the storage tank grid shell to add a temporary support system on the cone plate on the top of the storage tank. At the same time, temporary reinforcement measures are added to the center part of the grid shell to build a grid shell support system to improve the stability of the grid shell during the demolition process and avoid the risk of grid shell collapse due to unbalanced force.

[0032] In order to ensure the stability of the tank top grid shell during the demolition process, the original grid shell needs to be inspected twice before demolition, before reinforcement and before operation. The inspection methods are visual and tapping, especially at the nodes of the upper and lower chords of the grid shell. The nodes that are corroded and detached must be reinforced, and the unstable nodes also need to be strengthened to ensure the safety and reliability of the demolition construction.

[0033] Since the walkway slab and the grid shell are not considered to have any use, after the middle area is removed, the force transmission path of the chord rods through the middle area can only be transmitted through the peripheral chord rods, which will cause insufficient strength of the peripheral chord rods. Therefore, it is necessary to add fixing rods before removal to change the force transmission path of the grid shell and ensure the overall stability of the grid shell.

[0034] First, the grid shell is cut into an octagon, and then the reinforcement rod is made. Channel steel 16a can be used. Later, the dismantled unequal angle steel with the model of L180x 110x 10 is used. The reinforcement rod and the grid shell chord are hinged to ensure that the hinged part can move, the contact part is fully welded, and the welding is completed and passed the coloring test. The length of the component is set on site. Before dismantling, an auxiliary support system is required to support the original grid shell. After the auxiliary support system is made and installed, it must pass the coloring test. The layout method is to use the center line of the grid shell as the axis and rotate at an angle of 18 degrees along the periphery. Each grid shell is set with 20 auxiliary support systems. It is a tripod-type inclined support structure made of the original cone plate and the bracket. Its function is to ensure the safety of the grid shell. After calculation and verification, it can be seen that when the middle part of the grid shell is dismantled, the stress ratio of the auxiliary support structure is very low and almost unstressed, indicating that the added diagonal brace plays a role and changes the force transmission path. The general stress ratio of the diagonal brace is about 0.3, which meets the requirements of the specification.

[0035] After the walkway plate ring is removed, the integrity of the lattice shell structure continues to decrease and gradually becomes a cantilever structure. At this time, the auxiliary support structure becomes the main component, and the stress ratio gradually increases. When it reaches the outermost ring, the stress ratio of the auxiliary support structure is about 0.4, and the maximum tension is 15kN. 20 supports are about 30 tons (design value), which is close to the structure's own weight of 20 tons (standard value). This means that the chord no longer transmits force, and the main load is borne by the auxiliary support system. The deflection is not large, with a maximum of 40mm, which meets national standards and ensures that workers will not cause safety hazards due to excessive deflection during operation.

[0036] Two sets of movable working platforms are required for tank dismantling. The length and width of the platform are 1X6m. The platform plate is made of 5mm patterned steel plate or steel plate. Railings are set around to ensure the safety of construction operations. The height of the railing is 1200mm and the weight does not exceed 300kg. There are no more than 2 workers on each platform and no more than 10 workers on each tank. There are 6 lifting points on the platform. When working, the movable platform is lifted to the lattice shell dismantling position by a crane, and the two channel steels at the bottom of the platform are clamped on the chord of the lattice shell, and fixed with the chord by a movable slider. The steel plate can be made of the dismantled skin. Two movable platforms are made according to different areas. Different movable platforms are installed according to different areas during construction to meet the needs of safe operation of personnel. Since the patterned steel plate can be moderately bent according to the curvature of the lattice shell arch, anti-slip strips can be set on the platform plate.

[0037] Since a lot of cutting and lifting operations are required in the process of removing the top plate, a large amount of sparks and cutting waste will be generated during the operation. Therefore, it is necessary to protect the inner floating plate in advance. According to different cutting positions, fire blankets and steel springboards are laid in sequence on the inner floating plate at the bottom of the tank to protect the floating plate and prevent the cutting waste from damaging the floating plate, ensuring that the existing inner floating plate can meet the use requirements after the transformation is completed.

[0038] The tank grid shell is divided into demolition areas. The demolition of the tank grid shell is divided into the middle area, the walkway plate area, the secondary outer ring area, and the outer ring area. The demolition size is marked. Each piece is removed by a crane and then gas cutting and demolition are carried out in sequence. Finally, all the demolition work is completed. The retained tank bottom plate, wall plate and floating plate are not damaged, and the demolition work is completed.

[0039] In summary, the present invention solves the difficult problem of existing large-scale storage tank transformation, utilizes the stability of the storage tank itself, builds a grid shell support system, optimizes the demolition sequence, divides the storage tank grid shell into demolition areas, divides the demolition of the storage tank grid shell into regions, divides the grid shell into an intermediate area, a walkway plate area, a secondary outer ring area, and an outer ring area, and demolishes them in sequence, efficiently, safely, and with high quality to complete the demolition of the large-scale storage tank vault grid shell, the original floating plate, wall plate and bottom plate retained by the storage tank are not damaged, the construction quality and construction period are guaranteed, the demolition cost is greatly reduced, and it has significant social and economic benefits and has a reference value for promotion.

[0040] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention.

[0041] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A large tank vault removal process, characterized in that: The process steps include: Step 1: First, the grid shell is cut into an octagon, and then the reinforcement rod is made. The reinforcement rod and the grid shell chord are hinged to ensure that the hinged part can move and the contact part is fully welded. After the welding is completed, it is qualified by coloring test. The length of the component is set out on site, and then the auxiliary support system is set to support the original grid shell. The layout method is to use the center line of the grid shell as the axis, and the rotation angle is 18 degrees along the periphery. Each grid shell is set with 20 auxiliary support systems; Step 2: Make two sets of movable working platforms. The length and width of the platform are 1X6m. The platform plate is made of 5mm patterned steel plate or steel plate. Railings are set around to ensure the safety of construction operations. There are no more than 2 workers on each platform, and no more than 10 workers on each tank. There are 6 lifting points on the platform. The movable platform is lifted to the lattice shell removal position by a crane, and the two channel steels at the bottom of the platform are clamped on the chord of the lattice shell, and fixed with the chord by a movable slider. The steel plate is made of the dismantled skin. Two movable platforms are made according to different areas. Different movable platforms are installed according to different areas during construction to meet the needs of safe operation of personnel; Step 3: Divide the tank grid shell into demolition areas. Divide the tank grid shell into middle area, walkway plate area, sub-outer ring area, outer ring area, and mark the demolition size. Use a crane to lift each piece away, and perform gas cutting and demolition in sequence to complete all demolition work.

2. A large storage tank vault removal process according to claim 1, characterized in that: Before dismantling, a fire blanket and a steel springboard are laid on the inner floating plate at the bottom of the tank to prevent the cutting slag from damaging the floating plate.

3. A large storage tank vault removal process according to claim 1, characterized in that: In step three, the patterned steel plate is appropriately bent according to the curvature of the lattice shell arch, and an anti-slip strip is set on the platform plate.

4. A large storage tank vault removal process according to claim 1, characterized in that: The height of the railing in step 2 is 1200mm and the weight does not exceed 300kg.

5. A large storage tank vault removal process according to claim 1, characterized in that: In step 1, the support system uses the original cone plate and the bracket to make a diagonal support structure of the tripod.

6. A large storage tank vault removal process according to claim 1, characterized in that: Before demolition, the original grid shell needs to be inspected twice, once before reinforcement and once before operation, using visual and tapping methods.

7. A large storage tank vault removal process according to claim 1, characterized in that: In step 1, the reinforcement rod is made of channel steel and unequal angle steel that is removed later.

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