A method for repairing a settler

Abstract

The present invention discloses a settler maintenance method, which relates to the technical field of maintenance technology for large-scale refining equipment, comprising step one, prefabrication in the early stage; step two, dismantling and hoisting; and step three, installation and hoisting. The present invention can perform faster and better maintenance on settlers of a refinery production device, ensure maintenance quality, shorten maintenance period, and further reduce cost and labor intensity, mainly through the three steps of prefabrication in the early stage, dismantling and hoisting, and installation and hoisting.

Description

Technical Field

[0001] The present invention relates to the technical field of overhaul processes for large-scale refining and chemical equipment, and more particularly to the technical field of overhaul methods for settlers. Background Art

[0002] The settler is a critical piece of equipment in the refinery's catalytic cracking unit. It sits atop the first regenerator, 28 meters above the ground, with its gas stripping section extending approximately 10 meters into the vessel. After years of operation, its components have suffered from corrosion, wear, perforation, fracture, and blockage, necessitating repair or replacement. However, due to the outdated tools used in the original maintenance process, repairs relied entirely on manual handling and piecemeal installation. Many large components had to be prefabricated in sections, then installed, assembled, and welded inside the vessel. The cramped space inside made the operation challenging. Too many people would be unable to maneuver, while too few would make it difficult to move the workpiece. This delayed the work and made it difficult to ensure the quality of installation, assembly, and welding.

[0003] At the same time, the existing settler maintenance process mainly involves opening a manhole, and workers entering to cut the damaged parts into sections, which are then carried out manually and delivered to the surface. Then, prefabricated new parts are brought in and welded one by one. This not only wastes time, manpower and financial resources, but also cannot guarantee quality. Summary of the Invention

[0004] The purpose of the present invention is to solve the above technical problems and provide a settler maintenance method to ensure maintenance quality, shorten maintenance period, and further reduce cost and labor intensity.

[0005] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0006] A settler maintenance method comprises the following steps:

[0007] Step 1: Pre-production

[0008] 1.1. On-site prefabrication of the platform foundation and steel frame: According to the device layout and settler drawings, a square frame is made and the degree marks are made on the top for prefabrication work; large steel plates are laid on the prefabrication site as the platform foundation; the frame is placed on the platform foundation;

[0009] 1.2. Prefabrication of head;

[0010] 1.3. Prefabrication of the gas manifold: Roll the sheet metal into a cylinder; cut the sections according to the dimensions of each section, and trim the bevels to ensure the distance between the longitudinal welds; hoist the manifold onto the header, check whether the pre-drawn riser corresponds to the actual one, and perform drilling and polishing based on the actual one; insert the riser into the manifold and connect it to the header at the bottom; complete the lining of the manifold; 100% of the butt welds of the oil and gas manifold undergo RT testing, passing Level II; 100% of the fillet welds connecting the riser and manifold undergo PT testing, passing Level I;

[0011] 1.4. Prefabrication and Installation of Cyclone Separators: After the cyclones arrive on site, pre-assemble the coarse cyclones and coarse cyclone inlet distributors and check their fit. Allow for expansion during installation of the center tube and top cyclone distributor. Lift the top cyclone distributor and center tube onto the prefabricated frame and position them according to the pre-drawn degree lines. Transfer the top cyclone to the installation location using a manual hoist. Complete the welding of the top cyclone to the riser pipe and top cyclone DC distributor. During assembly, strictly control their verticality and horizontality. Use a theodolite to monitor verticality during welding.

[0012] Step 2: Dismantle and hoist: weld a lifting lug on the top of the original head, remove the bolts of the manhole of the settler; open all the manholes and loading and unloading doors of the settler; set up a scaffolding inside the settler to the top of the settler; remove the lining of the weld between the sinker head and the cylinder; fix the lower end of the sinker head weld with an annular ring; install two sets of H-shaped steel on the upper and lower heads respectively. When the lifting weight of the crane reaches 20T, use a 40T jack to loosen the head top, and then use the crane to add force to complete the lifting; remove the valves, vent lines, instrument lines, control valves and other pipelines that hinder the lifting of the sinker; remove the two expansion joints below the oil and gas riser. After the distillation tower is fixed, two expansion joints are connected. After the expansion joints are stopped, supports are installed after they are retracted. The girth weld at the top of the oil and gas riser is removed, and the oil and gas riser and the oil and gas manifold at the top of the settler are disconnected. The pipe fittings are hoisted to the ground. The cyclone riser on the top of the settler head is removed by cutting and removing it directly from the bottom of the original weld. The hexagonal oil and gas manifold is hoisted out as a whole and moved to the ground. Before cutting the head, mark the original head degree and cut along the center line of the head weld. When cutting, leave a 100mm range in each of the four directions and do not cut temporarily. The upper head and top swivel are hoisted and removed as a whole. After the old equipment is hoisted to the ground, it is leveled with a crane.

[0013] Step 3, installation and hoisting: the scaffolding is erected to the bottom of the coarse cyclone separator inlet, and the position of the coarse cyclone and coarse cyclone inlet distributor is reserved; the head weld is based on the weld centerline, aligned with an infrared level, and cut and polished; the hoisting of the head, top cyclone, center pipe and oil and gas collecting pipe is completed; the circumferential weld of the coarse cyclone separator inlet and the center pipe connecting pipe section is assembled and welded to ensure the verticality of the coarse cyclone separator and the horizontality of the inlet, and finally heat treatment and radiographic inspection are performed, and level II is qualified; the internal pressure pipe, loose steam pipe and other internal pipelines are reinstalled according to the status when they were dismantled. Note that the groove of this part of the pipeline must be polished during welding, and welding must be carried out in accordance with the welding process assessment and process card requirements; after the installation quality and welding quality are accepted, impurities and dirt on the grille are removed, and isolation measures are removed.

[0014] Furthermore, in step 1.1, the specific steps for on-site prefabrication of the platform foundation and steel frame are as follows:

[0015] 1.1.1. Steel plates are laid and welded on the prefabrication site to serve as the platform foundation;

[0016] 1.1.2. Cut the frame columns, beams, sweeping supports, and connecting plate inclined tubes, and make sure to leave a cutting line when cutting;

[0017] 1.1.3. Assemble the two door-type frames. Strictly control the design dimensions of the frames. After assembling, connect the scissor frame. The scissor frame must be in a free state when installing. After installation, complete the welding of the two door-type frames.

[0018] 1.1.4. Draw a ground pattern on the foundation platform, and place the two welded door frames sideways on the platform foundation. The two door frames should be parallel and perpendicular to the ground pattern, ensuring that the two frame beams are in a straight line at 90 degrees to the columns.

[0019] 1.1.5. When installing other beams, scissor braces and sweeping braces, and assembling the main and secondary beams of the roof frame, the beam surface must be flat. When joining the beams and secondary beams, the welding shrinkage should be considered. The spacing between beams can be appropriately increased. After the frame assembly is completed, the length, horizontal and vertical dimensions should be checked. If they do not meet the requirements, they should be corrected.

[0020] 1.1.6. Complete the welding of the entire frame and place it upright on the platform foundation;

[0021] 1.1.7. The welding of steel frame and top plate must be performed by qualified welders, and no missing welds or reduced weld height are allowed;

[0022] 1.1.8 When lifting the steel frame column assembly, lift it up from both the top and bottom simultaneously. The main hook is at the upper lifting point. The auxiliary hook is mainly used to prevent the bottom of the steel frame column from dragging on the ground. The main hook slowly lifts the assembly straight. During the straightening process, always keep the crane hook vertical. When the assembly is about to be vertical, it should be pulled with a rope to prevent the assembly from swinging violently at the moment of being lifted into the air and causing accidents.

[0023] 1.1.9. If the steel frame is not level after installation, install inclined irons under the foundation to level it. After leveling, weld the reserved steel plate at the bottom of the column to the bottom plate of the steel column;

[0024] 1.1.10. All welds are subjected to PT testing before the frame is erected.

[0025] Furthermore, in step 1.2, the specific steps of prefabrication of the head are:

[0026] After the head is measured on site, holes are drilled and reinforcement rings are installed according to the drawings. At the same time, the head lifting lugs and lifting pipe lifting lugs (a total of eight) are welded and polished, and PT testing is performed. After passing the on-site inspection, the degree lines are drawn on the head and the distributor pendant is installed.

[0027] Furthermore, in step 1.3, the specific steps of prefabrication of the head are:

[0028] 1.3.1. Roll the sheet into a cylinder;

[0029] 1.3.2. Cut the length of the cylinder sections according to the size of each section and repair the bevel to ensure that there is sufficient distance between the longitudinal welds;

[0030] 1.3.3. Pair the cylinder sections with the repaired interfaces into two groups. After the two interfaces are connected with tie rods, weld them. Use double-sided welding, with one side doing the base treatment and the other side doing the root cleaning and covering. Use J507R welding material. After welding, perform 100% RT inspection and pass the level II test.

[0031] 1.3.4. The two sets of semi-cylinder sections that have been inspected are transported to the site, welded, and inspected. The four riser assembly positions are pre-drawn below them according to the drawings.

[0032] 1.3.5. Hang the manifold onto the head, check whether the pre-drawn riser circle corresponds to the actual one, and make holes and polish according to the actual one;

[0033] 1.3.6. Insert the riser into the manifold, connect the bottom to the head and weld;

[0034] 1.3.7. Complete the lining work of the collecting pipe.

[0035] Furthermore, in step 1.4, the specific steps of cyclone prefabrication installation are:

[0036] 1.4.1. After the cyclone arrives at the site, the acceptance work shall be carried out: observe the product size, material, weld quality and lining condition;

[0037] 1.4.2. Pre-assemble the coarse-twist and coarse-twist inlet distributor and check their fit.

[0038] The beneficial effects of the present invention are as follows:

[0039] 1. This invention aims to address the various shortcomings of existing processes, enabling faster and better overhaul of settlers in oil refinery production facilities, ensuring overhaul quality, shortening overhaul periods, and further reducing costs and labor intensity. Based on practical applications, compared to existing technologies, this invention offers a wider range of applications, better results, lower costs, and ease of implementation and operation. It can be used for overhauling large-scale equipment in various industries, including oil refining and chemical engineering. The following uses the overhaul of a settler in an oil refinery as an example to illustrate the application and effectiveness.

[0040] 2. The settler of the catalytic cracking unit at a refinery is located atop the first regenerator, 32 meters above the ground. Its gas stripping section extends approximately 12.5 meters into the first regenerator. The first major overhaul relied entirely on manual handling and piecemeal installation. Many large components had to be prefabricated in sections, then installed, assembled, and welded inside the first regenerator. This involved 106 people, took 48 days, and cost a total of 12.0066 million yuan. The second major overhaul, with a similar workload, required only 28 people and a single crane, and completed the entire work in just 18 days, costing only 7.66 million yuan. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A schematic diagram of a settler overhaul process and method, cyclone prefabrication and assembly;

[0042] Figure 2 A settler overhaul process and method, schematic diagram of cyclone group hoisting;

[0043] Figure numerals: 1-steel frame, 2-scissors support, 3-oil and gas pipe, 4-head, 5-cyclone separator, 6-crane, 7-jib, 8-lifting eye, 9-manual hoist, 10-regenerator, 11-fixed cylinder, 12-wire rope. DETAILED DESCRIPTION

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0045] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0046] It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings. In addition, the terms "first," "second," etc. are used only to distinguish the descriptions and are not to be understood as indicating or implying relative importance.

[0047] In the description of the embodiments of the present invention, it should be noted that the terms "inside", "outside", "upper", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0048] Example 1

[0049] This embodiment provides a settler maintenance method, comprising the following steps:

[0050] Step 1: Pre-fabrication

[0051] 1.1. On-site prefabrication of the platform foundation and steel frame: According to the device layout and settler drawings, a square frame is made and the degree marks are made on the top for prefabrication work; large steel plates are laid on the prefabrication site as the platform foundation; the frame is placed on the platform foundation;

[0052] 1.2. Prefabrication of head;

[0053] 1.3. Prefabrication of the gas manifold: Roll the sheet metal into a cylinder; cut the sections according to the dimensions of each section, and trim the bevels to ensure the distance between the longitudinal welds; hoist the manifold onto the header, check whether the pre-drawn riser corresponds to the actual one, and perform drilling and polishing based on the actual one; insert the riser into the manifold and connect it to the header at the bottom; complete the lining of the manifold; 100% of the butt welds of the oil and gas manifold undergo RT testing, passing Level II; 100% of the fillet welds connecting the riser and manifold undergo PT testing, passing Level I;

[0054] 1.4. Prefabrication and Installation of Cyclone Separators: After the cyclones arrive on site, pre-assemble the coarse cyclones and coarse cyclone inlet distributors and check their fit. Allow for expansion during installation of the center tube and top cyclone distributor. Lift the top cyclone distributor and center tube onto the prefabricated frame and position them according to the pre-drawn degree lines. Transfer the top cyclone to the installation location using a manual hoist. Complete the welding of the top cyclone to the riser pipe and top cyclone DC distributor. During assembly, strictly control their verticality and horizontality. Use a theodolite to monitor verticality during welding.

[0055] Step 2: Dismantle and hoist: weld a lifting lug on the top of the original head, remove the bolts of the manhole of the settler; open all the manholes and loading and unloading doors of the settler; set up a scaffolding inside the settler to the top of the settler; remove the lining of the weld between the sinker head and the cylinder; fix the lower end of the sinker head weld with an annular ring; install two sets of H-shaped steel on the upper and lower heads respectively. When the lifting weight of the crane reaches 20T, use a 40T jack to loosen the head top, and then use the crane to add force to complete the lifting; remove the valves, vent lines, instrument lines, control valves and other pipelines that hinder the lifting of the sinker; remove the two expansion joints below the oil and gas riser. After the distillation tower is fixed, two expansion joints are connected. After the expansion joints are stopped, supports are installed after they are retracted. The girth weld at the top of the oil and gas riser is removed, and the oil and gas riser and the oil and gas manifold at the top of the settler are disconnected. The pipe fittings are hoisted to the ground. The cyclone riser on the top of the settler head is removed by cutting and removing it directly from the bottom of the original weld. The hexagonal oil and gas manifold is hoisted out as a whole and moved to the ground. Before cutting the head, mark the original head degree and cut along the center line of the head weld. When cutting, leave a 100mm range in each of the four directions and do not cut temporarily. The upper head and top swivel are hoisted and removed as a whole. After the old equipment is hoisted to the ground, it is leveled with a crane.

[0056] Step 3, installation and hoisting: the scaffolding is erected to the bottom of the coarse cyclone separator inlet, and the position of the coarse cyclone and coarse cyclone inlet distributor is reserved; the head weld is based on the weld centerline, aligned with an infrared level, and cut and polished; the hoisting of the head, top cyclone, center pipe and oil and gas collecting pipe is completed; the circumferential weld of the coarse cyclone separator inlet and the center pipe connecting pipe section is assembled and welded to ensure the verticality of the coarse cyclone separator and the horizontality of the inlet, and finally heat treatment and radiographic inspection are performed, and level II is qualified; the internal pressure pipe, loose steam pipe and other internal pipelines are reinstalled according to the status when they were dismantled. Note that the groove of this part of the pipeline must be polished during welding, and welding must be carried out in accordance with the welding process assessment and process card requirements; after the installation quality and welding quality are accepted, impurities and dirt on the grille are removed, and isolation measures are removed.

[0057] Example 2

[0058] This embodiment is a further optimization based on the embodiment 1, specifically:

[0059] In step 1.1, the specific steps for on-site prefabrication of the platform foundation and steel frame are as follows:

[0060] 1.1.1. Steel plates are laid and welded on the prefabrication site to serve as the platform foundation;

[0061] 1.1.2. Cut the frame columns, beams, sweeping supports, and connecting plate inclined tubes, and make sure to leave a cutting line when cutting;

[0062] 1.1.3. Assemble the two door-type frames. Strictly control the design dimensions of the frames. After assembling, connect the scissor frame. The scissor frame must be in a free state when installing. After installation, complete the welding of the two door-type frames.

[0063] 1.1.4. Draw a ground pattern on the foundation platform, and place the two welded door frames sideways on the platform foundation. The two door frames should be parallel and perpendicular to the ground pattern, ensuring that the two frame beams are in a straight line at 90 degrees to the columns.

[0064] 1.1.5. When installing other beams, scissor braces and sweeping braces, and assembling the main and secondary beams of the roof frame, the beam surface must be flat. When joining the beams and secondary beams, the welding shrinkage should be considered. The spacing between beams can be appropriately increased. After the frame assembly is completed, the length, horizontal and vertical dimensions should be checked. If they do not meet the requirements, they should be corrected.

[0065] 1.1.6. Complete the welding of the entire frame and place it upright on the platform foundation;

[0066] 1.1.7. The welding of steel frame and top plate must be performed by qualified welders, and no missing welds or reduced weld height are allowed;

[0067] 1.1.8 When lifting the steel frame column assembly, lift it up from both the top and bottom simultaneously. The main hook is at the upper lifting point. The auxiliary hook is mainly used to prevent the bottom of the steel frame column from dragging on the ground. The main hook slowly lifts the assembly straight. During the straightening process, always keep the crane hook vertical. When the assembly is about to be vertical, it should be pulled with a rope to prevent the assembly from swinging violently at the moment of being lifted into the air and causing accidents.

[0068] 1.1.9. If the steel frame is not level after installation, install inclined irons under the foundation to level it. After leveling, weld the reserved steel plate at the bottom of the column to the bottom plate of the steel column;

[0069] 1.1.10. All welds are subjected to PT testing before the frame is erected.

[0070] In step 1.2, the specific steps for prefabrication of the head are:

[0071] After the head is measured on site, holes are drilled and reinforcement rings are installed according to the drawings. At the same time, the head lifting lugs and lifting pipe lifting lugs (a total of eight) are welded and polished, and PT testing is performed. After passing the on-site inspection, the degree lines are drawn on the head and the distributor pendant is installed.

[0072] In step 1.3, the specific steps for prefabrication of the head are:

[0073] 1.3.1. Roll the sheet into a cylinder;

[0074] 1.3.2. Cut the length of the cylinder sections according to the size of each section and repair the bevel to ensure that there is sufficient distance between the longitudinal welds;

[0075] 1.3.3. Pair the cylinder sections with the repaired interfaces into two groups. After the two interfaces are connected with tie rods, weld them. Use double-sided welding, with one side doing the base treatment and the other side doing the root cleaning and covering. Use J507R welding material. After welding, perform 100% RT inspection and pass the level II test.

[0076] 1.3.4. The two sets of semi-cylinder sections that have been inspected are transported to the site, welded, and inspected. The four riser assembly positions are pre-drawn below them according to the drawings.

[0077] 1.3.5. Hang the manifold onto the head, check whether the pre-drawn riser circle corresponds to the actual one, and make holes and polish according to the actual one;

[0078] 1.3.6. Insert the riser into the manifold, connect the bottom to the head and weld;

[0079] 1.3.7. Complete the lining work of the collecting pipe.

[0080] In step 1.4, the specific steps for cyclone prefabrication installation are:

[0081] 1.4.1. After the cyclone arrives at the site, the acceptance work shall be carried out: observe the product size, material, weld quality and lining condition;

[0082] 1.4.2. Pre-assemble the coarse-twist and coarse-twist inlet distributor and check their fit.

[0083] Example 3

[0084] This embodiment is a further optimization based on the embodiment 1, specifically:

[0085] In step 2, the specific steps for dismantling and lifting are as follows:

[0086] 2.1. Stop the device and complete the replacement;

[0087] 2.2. Weld the lifting lugs on the top of the head and remove the bolts of the manhole of the settler;

[0088] 2.3. Open all manholes of the settler, and at the umbrella cap below the wing valve, roll the plate to make a cylinder and place it above the umbrella cap. Then lay a circular steel plate on the cylinder for isolation, pre-build a layer of scaffolding, and remove the manhole grille and beams.

[0089] 2.4. Set up the inner frame to the top of the settler for cleaning the coke, removing the lining and cutting the weld seam of the head;

[0090] 2.5. Remove the lining within the weld between the settler head and the cylinder;

[0091] 2.6. Add a ring to the lower end of the weld of the settler head to fix it, so as to avoid large deformation after the head is cut off and it cannot be assembled with the new head;

[0092] 2.7. During hoisting, in order to prevent the crane from excessively pulling the load, causing the load to suddenly bounce up and cause setbacks, which may lead to accidents, two sets of H-shaped steel are installed on the upper and lower heads. When the crane's lifting weight reaches 20 tons, use a jack to loosen the head, and then use the crane to add force to complete the hoisting.

[0093] 2.8. Cutting of the coarse cyclone separator inlet inside the settler. This weld is removed for protection and a correction amount is reserved.

[0094] 2.9. Remove the valves, vent lines, instrument lines, control valves and other pipelines on the top of the settler that hinder the lifting of the settler;

[0095] 2.10. Remove the top valve bolts and hang the valve group connecting vent pipe to the ground;

[0096] 2.11. Cut off the top platform connection and hoist the platform to the ground;

[0097] 2.12. The oil and gas riser is fixed with two expansion joints at the bottom. The distillation tower is connected with two expansion joints. Channel steel or steel plate is used to support the expansion joint. After parking, the expansion joint is contracted and then supported.

[0098] 2.13. The oil and gas riser is supported and fixed with a pair of north-south spring hangers above the support, which is in the east-west direction.

[0099] 2.14. Cut off the girth weld at the top of the oil and gas riser, disconnect the oil and gas riser and the oil and gas manifold at the top of the settler; and hoist the pipes to the ground;

[0100] 2.15. Cut off the top platform of the settler and hoist it to the ground;

[0101] 2.16. Cut off the cyclone separator riser pipe on the top cover of the settler, remove the circumferential weld directly from the lower part of the original weld; hoist the hexagonal oil and gas manifold down as a whole and hoist the oil and gas manifold to the ground;

[0102] 2.17. Removal of the center tube positioning ring;

[0103] 2.18. Before cutting the head, mark the original head degree and cut along the center line of the head weld. Leave a certain non-cutting range in each of the four directions when cutting. Cut this position after the hoisting conditions are met. Then cut the head weld on the settler and make the degree transfer mark before cutting;

[0104] 2.19. Remove the inner frame to facilitate rough installation, ensuring that the dismantled section is disconnected from the reused equipment;

[0105] 2.20. The upper head and top rotation are hoisted and removed as a whole. After the old equipment is hoisted to the ground, it is leveled with a crane tail;

[0106] 2.21. Dismantle and separate the old equipment and transport them away from the site;

[0107] 2.22. Roughly rotate and remove the center tube and hoist it to the ground.

[0108] Example 4

[0109] This embodiment is a further optimization based on the embodiment 1, specifically:

[0110] In step three, the specific steps for installation and lifting are as follows:

[0111] 3.1. Build the scaffolding to the entrance of the coarse cyclone separator and reserve the positions for the coarse cyclone and coarse cyclone inlet distributor;

[0112] 3.2. Correct the inlet groove of the coarse cyclone separator of the old equipment and complete the grinding. The groove should be flush. At the same time, the coarse cyclone support should be replaced. After welding, perform PT testing.

[0113] 3.3. Complete the coarse cyclone inlet distributor and coarse cyclone hoisting work, place the coarse cyclone main body on the coarse cyclone fixing bracket and connect it to the cylinder. After the coarse cyclone is hoisted into place, install the coarse cyclone pull rod and fix it with points. Reserve the installation position of the center pipe in the middle. First connect the coarse cyclone separator and the inlet pipe mouth. The misalignment should not exceed 3mm. And control its verticality and horizontality. Then assemble the inlet distributor and coarse cyclone. The elevation of the cyclone separator inlet should have a deviation of no more than 5mm.

[0114] 3.4. The head weld should be aligned with the weld centerline as the reference, and then cut and polished with an infrared level. Leveling and alignment should be done in two or more directions at right angles to each other in the same plane, and the levelness should be measured with an infrared level. If the deviation is large, hand grinding and adjustment are required.

[0115] 3.5. Complete the installation of the head, top rotation, center pipe and oil and gas manifold. When assembling the head, first place the guide plate on the upper mouth of the cylinder, and align it with the original equipment cylinder according to the degree mark reserved during the previous disassembly. The head welding adopts the form of double-sided welding, with one side bottoming and the other side root cleaning and covering. The welding material is J507R, and the weld is subjected to 100% RT inspection;

[0116] 3.6. Erect scaffolding to the top;

[0117] 3.7. Assemble and weld the girth weld of the connecting pipe section between the coarse cyclone separator inlet and the central pipe to ensure the verticality of the coarse cyclone separator and the horizontality of the inlet. Finally, perform heat treatment and flaw detection.

[0118] 3.8. Install the material legs to ensure their verticality and concentricity;

[0119] 3.9. Install the leg bracket and the rough-spin bracket and fix them. The center line of each layer of tie rod should be on the same horizontal plane with an inclination of no more than 2mm. Complete the top-spin and rough-spin tie rod connecting plates by welding. The connecting plates should have air holes reserved. The tie rods should be welded firmly to the corresponding connecting plates. Do not assemble them forcefully during welding to ensure the designed position and distance between them.

[0120] 3.10. Weld the material legs and supports and perform heat treatment;

[0121] 3.11. Allowance should be left when cutting the slugs. Depending on the actual situation, remove the excess slugs before installing the wing valve. During installation, adjust the center of the wing plate of the wing valve to the tangent or centripetal direction of the wing valve distribution circle. The wing valve outlet installation direction: the wing valve is in the tangent direction of the circle. Depending on the actual situation on site, place the frame level vertically against the radial side of the wing valve. Use a jack to adjust the verticality of the two radial sides of the wing valve with the wall of the settler as the fulcrum. When the bubble at the upper end of the frame level is stable in the center position, spot weld the two positions of the wing valve pipe outlet.

[0122] After spot welding, measure the inclination angle of the wing plate again. If the angle between the wing plate and the vertical line has not changed, proceed to the next step of base welding. If there is a deviation, grind off the spot welding part and repeat the assembly step until there is no deviation.

[0123] 3.12. Complete the installation of the center tube positioning ring support;

[0124] 3.13. Reinstall the internal pressure pipes, loose steam pipes and other internal pipelines according to the state when they were dismantled;

[0125] 3.14, lining restoration;

[0126] 3.15. Dismantle scaffolding;

[0127] 3.16, Manhole platform and grille restored;

[0128] 3.17. Top operating platform restored;

[0129] 3.18. Restore the top valve, vent line, instrument line, and control valve of the settler;

[0130] 3.19. Remove the oil and gas riser supports;

[0131] 3.20. After the installation quality and welding quality are accepted, remove impurities and dirt on the grille and remove the isolation measures;

[0132] 3.21. Reinstall the manhole and conduct a test run.

Claims

1. A settler maintenance method, characterized in that: The steps include: Step 1: Pre-fabrication 1.

1. On-site prefabrication of the platform foundation and steel frame: According to the device layout and settler drawings, a square frame is made and the degree marks are made on the top for prefabrication work; large steel plates are laid on the prefabrication site as the platform foundation; the frame is placed on the platform foundation; 1.

2. Prefabrication of head; 1.

3. Prefabrication of the gas manifold: Roll the sheet metal into a cylinder; cut the sections according to the dimensions of each section, and trim the bevels to ensure the distance between the longitudinal welds; hoist the manifold onto the header, check whether the pre-drawn riser corresponds to the actual one, and perform drilling and polishing based on the actual one; insert the riser into the manifold and connect it to the header at the bottom; complete the lining of the manifold; 100% of the butt welds of the oil and gas manifold undergo RT testing, passing Level II; 100% of the fillet welds connecting the riser and manifold undergo PT testing, passing Level I; 1.

4. Prefabrication and Installation of Cyclone Separators: After the cyclones arrive on site, pre-assemble the coarse cyclones and coarse cyclone inlet distributors and check their fit. Allow for expansion during installation of the center tube and top cyclone distributor. Lift the top cyclone distributor and center tube onto the prefabricated frame and position them according to the pre-drawn degree lines. Transfer the top cyclone to the installation location using a manual hoist. Complete the welding of the top cyclone to the riser pipe and top cyclone DC distributor. During assembly, strictly control their verticality and horizontality. Use a theodolite to monitor verticality during welding. Step 2: Dismantling and lifting: Weld a lifting lug on the top of the original head and remove the manhole bolts of the settler; open all manholes and loading and unloading doors of the settler; set up scaffolding inside the settler to the top of the settler; remove the lining at the weld between the settler head and the cylinder; fix the lower end of the settler head weld with an annular ring; install two sets of H-shaped steel on the upper and lower heads respectively. When the crane lifting weight reaches 20T, use a 40T jack to loosen the head top, and then use the crane to add force to complete the lifting; remove the valves, vent lines, instrument lines, control valves and other pipelines on the top of the settler that hinder the lifting of the settler; The oil and gas riser is fixed with two expansion joints at the bottom, and the distillation tower is connected with two expansion joints. After the tower is shut down, the expansion joints are contracted and then supported. Remove the girth weld at the top of the oil and gas riser, disconnect the oil and gas riser and the oil and gas manifold at the top of the settler; and hoist the pipe fittings to the ground; remove the cyclone separator riser pipe on the top of the settler head by cutting and removing it directly from the bottom of the original weld; hoist the hexagonal oil and gas manifold as a whole and move it to the ground; Mark the original head degree before cutting, cut along the center line of the head weld, and leave 100mm in each of the four directions without cutting; hoist and remove the upper head and top rotation as a whole, hoist the old equipment to the ground, and level it with a crane; Step 3, installation and hoisting: the scaffolding is erected to the bottom of the coarse cyclone separator inlet, and the position of the coarse cyclone and coarse cyclone inlet distributor is reserved; the head weld is based on the weld centerline, aligned with an infrared level, and cut and polished; the hoisting of the head, top cyclone, center pipe and oil and gas collecting pipe is completed; the circumferential weld of the coarse cyclone separator inlet and the center pipe connecting pipe section is assembled and welded to ensure the verticality of the coarse cyclone separator and the horizontality of the inlet, and finally heat treatment and radiographic inspection are performed, and level II is qualified; the internal pressure pipe, loose steam pipe and other internal pipelines are reinstalled according to the status when they were dismantled. Note that the groove of this part of the pipeline must be polished during welding, and welding must be carried out in accordance with the welding process assessment and process card requirements; after the installation quality and welding quality are accepted, impurities and dirt on the grille are removed, and isolation measures are removed.

2. A settler maintenance method according to claim 1, characterized in that: In step 1.1, the specific steps for on-site prefabrication of the platform foundation and steel frame are as follows: 1.1.

1. Steel plates are laid and welded on the prefabrication site to serve as the platform foundation; 1.1.

2. Cut the frame columns, beams, sweeping supports, and connecting plate inclined tubes, and make sure to leave a cutting line when cutting; 1.1.

3. Assemble the two door-type frames. Strictly control the design dimensions of the frames. After assembling, connect the scissor frame. The scissor frame must be in a free state when installing. After installation, complete the welding of the two door-type frames. 1.1.

4. Draw a ground pattern on the foundation platform, and place the two welded door frames sideways on the platform foundation. The two door frames should be parallel and perpendicular to the ground pattern, ensuring that the two frame beams are in a straight line at 90 degrees to the columns. 1.1.

5. When installing other beams, scissor braces and sweeping braces, and assembling the main and secondary beams of the roof frame, the beam surface must be flat. When joining the beams and secondary beams, the welding shrinkage should be considered. The spacing between beams can be appropriately increased. After the frame assembly is completed, the length, horizontal and vertical dimensions should be checked. If they do not meet the requirements, they should be corrected. 1.1.

6. Complete the welding of the entire frame and place it upright on the platform foundation; 1.1.

7. The welding of steel frame and top plate must be performed by qualified welders, and no missing welds or reduced weld height are allowed; 1.1.8 When lifting the steel frame column assembly, lift it up from both the top and bottom simultaneously. The main hook is at the upper lifting point. The auxiliary hook is mainly used to prevent the bottom of the steel frame column from dragging on the ground. The main hook slowly lifts the assembly straight. During the straightening process, always keep the crane hook vertical. When the assembly is about to be vertical, it should be pulled with a rope to prevent the assembly from swinging violently at the moment of being lifted into the air and causing accidents. 1.1.

9. If the steel frame is not level after installation, install inclined irons under the foundation to level it. After leveling, weld the reserved steel plate at the bottom of the column to the bottom plate of the steel column; 1.1.

10. All welds are subjected to PT testing before the frame is erected.

3. A settler maintenance method according to claim 1, characterized in that: In step 1.2, the specific steps of prefabrication of the head are as follows: after on-site measurement of the head, holes are drilled according to the drawings and reinforcement rings are installed. At the same time, the head lifting ears and lifting pipe lifting ears (a total of eight) are welded and polished, and PT testing is performed. After they are transported to the site for inspection and pass, degree lines are drawn on the head and the distributor pendant is installed.

4. A settler maintenance method according to claim 1, characterized in that: In step 1.3, the specific steps for prefabrication of the head are: 1.3.

1. Roll the sheet into a cylinder; 1.3.

2. Cut the length of the cylinder sections according to the size of each section and repair the bevel to ensure that there is sufficient distance between the longitudinal welds; 1.3.

3. Pair the cylinder sections with the repaired interfaces into two groups. After the two interfaces are connected with tie rods, weld them. Use double-sided welding, with one side doing the base treatment and the other side doing the root cleaning and covering. Use J507R welding material. After welding, perform 100% RT inspection and pass the level II test. 1.3.

4. The two sets of semi-cylinder sections that have been inspected are transported to the site, welded, and inspected. The four riser assembly positions are pre-drawn below them according to the drawings. 1.3.

5. Hang the manifold onto the head, check whether the pre-drawn riser circle corresponds to the actual one, and make holes and polish according to the actual one; 1.3.

6. Insert the riser into the manifold, connect the bottom to the head and weld; 1.3.

7. Complete the lining work of the collecting pipe.

5. A settler maintenance method according to claim 1, characterized in that: In step 1.4, the specific steps for cyclone prefabrication installation are: 1.4.

1. After the cyclone arrives at the site, the acceptance work shall be carried out: observe the product size, material, weld quality and lining condition; 1.4.

2. Pre-assemble the coarse-twist and coarse-twist inlet distributor and check their fit.

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