A pipeline construction platform and purging method for thermal power units

Abstract

This invention discloses a construction platform and purging method for pipelines in thermal power units. The construction platform includes supports, support plates, a lower arc-shaped plate, and an upper arc-shaped plate. Four supports are used, with support plates positioned between them. First pillars penetrate both ends of the support plates, and reinforcing plates are installed at the ends of two of the first pillars. First displacement blocks are slidably connected to the reinforcing plates, and second pillars penetrate the first displacement blocks. A top plate is installed on top of the second pillars, and a second displacement block is slidably connected to the top plate. A lower arc-shaped plate is installed on top of the second displacement blocks, and an upper arc-shaped plate is installed above the lower arc-shaped plate. This invention utilizes BIM modeling and modular assembly to optimize construction procedures, significantly reducing the risks of overlapping operations and high-altitude work, effectively ensuring construction safety. By adding a sealing valve between the target plate frame and the purging pipeline, the steam pipeline is completely isolated from the target plate device when removing the target plate, avoiding the safety hazard of steam leakage and burns to construction personnel during target plate replacement. It is convenient to use, simple to operate, and easy to promote.

Description

Technical Field

[0001] This invention relates to a pipeline purging method, and more particularly to a pipeline construction platform and purging method for thermal power units, belonging to the technical field of temporary pipeline installation for steam purging. Background Technology

[0002] During the installation of thermal power units, the blowing of superheaters, reheaters, and steam pipelines is an important process before the thermal power units are put into operation. Its purpose is to use steam as power to blow clean the relevant steam pipelines and equipment to remove various impurities accumulated inside during manufacturing, transportation, storage, and installation, so that qualified steam can enter the steam turbine, thereby preventing pipe bursts and damage to the steam turbine flow passage during unit operation, improving the safety and economy of the unit, and ensuring the safe operation of the unit.

[0003] Currently, with the increase in unit capacity and parameters, the number of once-through boilers is gradually increasing. The blowdown of once-through boilers all adopts pressure-stabilized blowdown, which puts forward higher requirements on the installation quality of temporary pipelines and the safety of the purging target plate device. In response to the conventional steam purging temporary pipeline installation technology and process, we have focused on reforming and innovating the construction process and methods. We have adopted BIM modeling + modular assembly to form a mature and effective set of technical achievements. Through practical application, it has significantly reduced the installation period, reduced the construction difficulty, improved the project quality, and saved construction costs, achieving good results. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a construction platform and purging method for pipelines of thermal power units. By using BIM modeling technology to simulate the construction in advance, the installation period is reduced, the construction difficulty is reduced, the project quality is improved, and the construction cost is saved, which has achieved good results.

[0005] The technical solution adopted by this invention to solve the technical problem is as follows:

[0006] A pipeline construction platform for thermal power units includes a support, a support plate, a lower arc plate, and an upper arc plate (12). There are four supports, and a support plate is set between the supports. A first support column passes through both ends of the support plate, and a reinforcing plate is set at the ends of the two first support columns. A first displacement block is slidably connected to the reinforcing plate. A second support column passes through the first displacement block. A top plate is set at the top of the second support column. A second displacement block is slidably connected to the top plate. A lower arc plate is set at the top of the second displacement block. An upper arc plate is set above the lower arc plate.

[0007] A crossbar is provided between the brackets, and the support plate is fixedly connected to the crossbar by a clamp.

[0008] The first support column is fixedly connected to the support plate by bolts, and the reinforcing plate is located outside the bracket and is fixedly connected to the first support column by bolts.

[0009] There are two top plates, located above the support frame. The second support column is fixedly connected to the first displacement block by bolts, and the second displacement block is fixedly connected to the top plate by bolts.

[0010] The lower arc-shaped plate has screws at both ends, the upper arc-shaped plate passes through the screws, and a matching nut is screwed onto the end of the screw.

[0011] The method for purging pipelines of a thermal power unit includes the following steps:

[0012] S1. Prepare the materials required for construction and inspect them. Since most of the materials are reused, and most pipe fittings have straight sections of varying lengths, a multi-functional elbow measuring ruler is needed to quickly measure the bending radius and straight section length of the elbows.

[0013] S2. Use BIM modeling technology to check the temporary pipeline installation route and input the actual length data of each material into BIM. Simulate the assembly of different materials in BIM to achieve reasonable reuse of each material. After the modeling is completed, pre-assemble each module on the ground. Divide the pipeline into different pipe segment modules according to the actual situation and number each pipe segment module for on-site installation.

[0014] S3. Cut materials according to module dimensions using a full-diameter multi-purpose plasma pipe beveling machine to cut bevels; before pipe construction, clearly explain the direction and amount of thermal expansion of the entire pipe section, and thoroughly clean the inside of the pipe; during butt jointing, use pipe alignment tools for quick alignment; pipe sections 10-15mm from the weld edge should be thoroughly derusted and oil-free to expose the metallic luster; temporary pipes should be naturally aligned with dummy valves and permanent pipes, and forced alignment is not allowed;

[0015] S4. In front of the target plate, all temporary pipes should be internally derusted to ensure that the inside of the pipes is clean and free of debris. All welding should be done with argon arc welding for the root pass. After welding, the weld joint should be heat treated. During heat treatment, no external force should be applied to the vicinity of the weld joint or the pipe.

[0016] S5. Disconnect the four main steam drain pipes and the one drain pipe before the high-pressure bypass valve between the manual valve and the pneumatic drain valve, connect them to a temporary pipe and connect them to the high-pressure side of the φ159x7 drain header pipe along with the two drain pipes before the temporary control valve, and discharge them to the outside of the turbine hall expansion end; disconnect the four high-temperature reheat steam drain pipes and the four low-temperature reheat steam drain pipes between the manual valve and the pneumatic drain valve, connect them to the low-pressure side of the φ159x7 drain header pipe along with the drain pipe before the particle collector, discharge them to the outside of the turbine hall expansion end and reinforce them, the wall thickness should not be less than 6mm, and the slope of the temporary drain pipe should be 3‰;

[0017] S6. The target plate of the temporary exhaust pipe shall be installed on the straight pipe section, with the straight pipe section before and after the installation being no less than 5 meters, and close to the permanent pipe. The target plate device shall be installed on the straight pipe section of the temporary pipe and close to the end of the permanent pipe. The length of the straight pipe section before the device shall be no less than 5 times the pipe diameter, and the length of the straight pipe section after the device shall be no less than 3 times the pipe diameter.

[0018] S7. When installing drain pipes, their layout and direction should be reasonable, and they should have a slope of 3‰; all drain pipe interfaces to the turbine drain expansion tank should be completely isolated during the blowdown process.

[0019] S8. Install one 0-1MPa pressure measuring point and one 0-600℃ temperature measuring point 500mm away from the exhaust port on the temporary exhaust pipe. The signals are led to the DCS for easy observation and recording.

[0020] S9. Erect two frames around the target plate location; Dimensions of the target plate inspection platform: 3 meters wide, 4 meters long, and 1.2 meters above the target plate axis. Ramps are erected on both sides to facilitate personnel going up and down.

[0021] S10. Erect scaffolding 10m long, 5m wide and 10m high around the silencer to prevent debris blown out of the blowpipe from splashing everywhere; the silencer and the external pipeline are hoisted and connected by a 25T truck crane; the silencer foundation should be flat and compacted, installed firmly, with room for movement to avoid large vibrations; place two 5T beaters under the silencer, and install Y-direction guide devices and anti-backward limit devices on the beaters;

[0022] S11. When installing valves, check whether the valve switches are flexible and the indication is correct. Clean the valve thoroughly and keep it closed to prevent debris from entering. When welding valves, do not close them to prevent overheating and deformation. The inlet and outlet directions of the valves must be consistent with the direction indicated by the arrows on the valve body.

[0023] S12. Before pouring the main platform, plan the route of the blow pipe in advance and embed steel plates according to the route. Pour the blow pipe together with the platform. When constructing the blow pipe support, the I-beams can be directly welded to the embedded iron to enhance the strength of the support.

[0024] S13. Weld clamps on both sides of the support to better limit the reaction force, linear displacement and angular displacement of the steam flow during pipeline blowing; weld limiting supports at the outlet of the high-pressure main steam valve and reheat steam valve, and weld sliding supports at the intermediate pipe section.

[0025] S14. When fabricating the support, leave an appropriate expansion gap on the left, right and top sides of the pipe and the support. The temporary support is only allowed to expand in the direction of steam flow and is not allowed to move in the opposite direction. During the blowing process, carefully observe the load-bearing condition of the pipe and the support and check the free expansion of the pipe.

[0026] S15. The steam pipeline is purged in two stages. The first stage of purging adopts a pressure-stabilizing purging method. As the separator pressure gradually rises, the temporary control valve is gradually opened. When the separator pressure rises to 7.5MPa, the steam flow rate reaches 920-1000t / h, and the first stage of purging begins. The first stage of pressure-stabilizing purging is performed once. After 1-2 hours of pressure stabilizing purging, the main steam temporary control valve is gradually closed. The separator pressure is reduced to 5.0MPa, and the bypass pipeline is purged once. After the above purging is completed, the boiler is shut down according to the normal shutdown procedure.

[0027] S16. After the first stage of pressure stabilization and blowdown shutdown, the particle collector shall be removed during this period, and the system shall be restored to prepare for the second stage of blowdown. Depending on the water quality, it shall be decided whether to drain all water. If water is drained, the condenser, deaerator, condensate pump inlet filter, and feedwater pump inlet filter shall be manually cleaned.

[0028] S17. After the particle collector is removed, the second stage of steam blowing begins; the second stage of steam blowing adopts a pressure-stabilized steam blowing method. As the separator pressure gradually rises, the temporary control valve gradually opens. When the separator pressure rises to 7.5MPa, the steam flow rate reaches 920-1000t / h, and the second stage of steam blowing begins. After stabilizing the pressure and blowing for 1-2 hours, the target plate is replaced using a pressure-reducing steam blowing method. If the target plate is qualified, the combustion rate is gradually reduced, the temporary control valve for steam blowing is closed, and the separator pressure is reduced to 5.0MPa. The bypass pipeline is then purged once. After the steam blowing is completed, the boiler is shut down according to the normal shutdown procedure.

[0029] S18. After the blowdown is completed, wait for the system temperature to drop below the safe temperature, dismantle the temporary system and restore the pipeline according to the requirements of the formal system. Each weld joint should be supervised and inspected by four parties and recorded with signatures.

[0030] The construction method for a temporary pipeline construction platform for steam purging of a thermal power unit requires the following steps when hoisting the pipeline bend:

[0031] S1. First, install a temporary pipeline construction platform for steam purging of thermal power units at the elbow. Then, move the top plate above the elbow joint and use a lifting device to lower the elbow onto the lower arc plate. Finally, fix the elbow with the upper arc plate.

[0032] S2. Move the second displacement block to align the lower end of the elbow with the pipe. After alignment, perform welding. Once welding is complete, remove the upper and lower arc plates.

[0033] The positive and beneficial effects of this invention are:

[0034] 1. This invention facilitates the alignment and welding of pipe bends by setting up a construction platform for thermal power unit pipelines; at the same time, it supports the bends and prevents swaying and instability when the pipeline is in a semi-suspended state during construction. It is convenient to use and simple to operate.

[0035] 2. This invention uses BIM modeling technology to accurately and quickly determine the temporary pipeline installation route. The length data of each material is input into the BIM. By simulating the assembly of different materials in the BIM, each material can be reused rationally. After the modeling is completed, each module is pre-assembled on the ground. According to the actual situation, the pipeline is divided into different pipe segment modules, and each pipe segment module is numbered for on-site installation, making construction more convenient and faster, reducing labor intensity and saving costs.

[0036] 3. This invention pre-plans the route of the blowdown pipeline and pre-embeds steel plates according to the route, which are then poured together with the platform. During the construction of the blowdown pipeline support, the I-beams can be directly welded to the embedded iron to enhance the strength of the support. Based on the pipeline layout and its stress calculation, as well as the characteristics of different types of supports, the principle of support selection is determined, which standardizes and rationalizes the construction and selection of supports, greatly improves the installation progress, and results in a neat, simple, uniform, and beautiful appearance.

[0037] 4. By adding a sealing valve between the target plate frame and the purging pipe, the present invention completely isolates the steam pipe from the target plate device when the target plate is removed, avoiding the safety hazard of steam leakage and burns to construction personnel during the target plate replacement process, and greatly improving the operating efficiency and safety of the target plate device. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the structure of the present invention;

[0039] Figure 2 This is a schematic diagram of the support plate of the present invention;

[0040] Figure 3 This is a schematic diagram of the fixture of the present invention;

[0041] Figure 4This is a distribution diagram of the temporary unblocking pipes according to the present invention;

[0042] Wherein: 1-bracket, 2-crossbar, 3-support plate, 4-clamp, 5-first support column, 6-reinforcing plate, 7-first displacement block, 8-second support column, 9-top plate, 10-second displacement block, 11-lower arc plate, 12-upper arc plate, 13-screw. Detailed Implementation

[0043] The invention will be further explained and described below with reference to the accompanying drawings:

[0044] Example 1, see Figures 1-3 A pipeline construction platform for thermal power units includes a support 1, a support plate 3, a lower arc plate 11, and an upper arc plate 12. There are four supports 1, and the support plate 3 is arranged between the supports 1. The two ends of the support plate 3 are penetrated by a first support column 5, and a reinforcing plate 6 is arranged at the ends of two first support columns 5. A first displacement block 7 is slidably connected to the reinforcing plate 6. A second support column 8 is penetrated through the first displacement block 7. A top plate 9 is arranged on the top of the second support column 8. A second displacement block 10 is slidably connected to the top plate 9. A lower arc plate 11 is arranged on the top of the second displacement block 10, and an upper arc plate 12 is arranged above the lower arc plate 11.

[0045] A crossbar 2 is provided between the brackets 1, and the support plate 3 is fixedly connected to the crossbar 2 by a clamp 4.

[0046] The first support column 5 is fixedly connected to the support plate 3 by bolts, and the reinforcing plate 6 is located outside the bracket 1 and is fixedly connected to the first support column 5 by bolts.

[0047] There are two top plates 9, located above the support 1 respectively. The second column 8 is fixedly connected to the first displacement block 7 by bolts, and the second displacement block 10 is fixedly connected to the top plate 9 by bolts.

[0048] The lower arc plate 11 has screws 13 at both ends, the upper arc plate 12 passes through the screws 13, and a matching nut is screwed onto the end of the screws 13.

[0049] In the above description, the clamp consists of two arc-shaped plates, which are distributed symmetrically at the top and bottom. One arc-shaped plate is fixedly connected to the bottom of the support plate, and screws are provided on both sides of the bottom of the arc-shaped plate. The other arc-shaped plate is sleeved on the screws of the upper arc-shaped plate and fixed by matching nuts.

[0050] In the above description, the position of the clamp corresponds to the position of the crossbar.

[0051] In the above description, the top plate extends out from both sides of the support.

[0052] In the above description, through holes are drilled at both ends of the top plate, and guide cylinders are installed at the through holes; through holes are drilled on the first displacement block, and guide cylinders are installed above the through holes; tightening bolts are respectively installed on the outside of the two guide cylinders.

[0053] Example 2, see Figure 4 The above-described method for purging pipelines in a thermal power unit includes the following steps:

[0054] S1. Prepare the materials required for construction and inspect them. Since most of the materials are reused, and most pipe fittings have straight sections of varying lengths, a multi-functional elbow measuring ruler is needed to quickly measure the bending radius and straight section length of the elbows.

[0055] S2. Use BIM modeling technology to check the temporary pipeline installation route and input the actual length data of each material into BIM. Simulate the assembly of different materials in BIM to achieve reasonable reuse of each material. After the modeling is completed, pre-assemble each module on the ground. Divide the pipeline into different pipe segment modules according to the actual situation and number each pipe segment module for on-site installation.

[0056] S3. Cut materials according to module dimensions using a full-diameter multi-purpose plasma pipe beveling machine to cut bevels; before pipe construction, clearly explain the direction and amount of thermal expansion of the entire pipe section, and thoroughly clean the inside of the pipe; during butt jointing, use pipe alignment tools for quick alignment; pipe sections 10-15mm from the weld edge should be thoroughly derusted and oil-free to expose the metallic luster; temporary pipes should be naturally aligned with dummy valves and permanent pipes, and forced alignment is not allowed;

[0057] S4. In front of the target plate, all temporary pipes should be internally derusted to ensure that the inside of the pipes is clean and free of debris. All welding should be done with argon arc welding for the root pass. After welding, the weld joint should be heat treated. During heat treatment, no external force should be applied to the vicinity of the weld joint or the pipe.

[0058] S5. Disconnect the four main steam drain pipes and the one drain pipe before the high-pressure bypass valve between the manual valve and the pneumatic drain valve, connect them to a temporary pipe and connect them to the high-pressure side of the φ159x7 drain header pipe along with the two drain pipes before the temporary control valve, and discharge them to the outside of the turbine hall expansion end; disconnect the four high-temperature reheat steam drain pipes and the four low-temperature reheat steam drain pipes between the manual valve and the pneumatic drain valve, connect them to the low-pressure side of the φ159x7 drain header pipe along with the drain pipe before the particle collector, discharge them to the outside of the turbine hall expansion end and reinforce them, the wall thickness should not be less than 6mm, and the slope of the temporary drain pipe should be 3‰;

[0059] S6. The target plate of the temporary exhaust pipe shall be installed on the straight pipe section, with the straight pipe section before and after the installation being no less than 5 meters, and close to the permanent pipe. The target plate device shall be installed on the straight pipe section of the temporary pipe and close to the end of the permanent pipe. The length of the straight pipe section before the device shall be no less than 5 times the pipe diameter, and the length of the straight pipe section after the device shall be no less than 3 times the pipe diameter.

[0060] S7. When installing drain pipes, their layout and direction should be reasonable, and they should have a slope of 3‰; all drain pipe interfaces to the turbine drain expansion tank should be completely isolated during the blowdown process.

[0061] S8. Install one 0-1MPa pressure measuring point and one 0-600℃ temperature measuring point 500mm away from the exhaust port on the temporary exhaust pipe. The signals are led to the DCS for easy observation and recording.

[0062] S9. Erect two frames around the target plate location; Dimensions of the target plate inspection platform: 3 meters wide, 4 meters long, and 1.2 meters above the target plate axis. Ramps are erected on both sides to facilitate personnel going up and down.

[0063] S10. Erect scaffolding 10m long, 5m wide and 10m high around the silencer to prevent debris blown out of the blowpipe from splashing everywhere; the silencer and the external pipeline are hoisted and connected by a 25T truck crane; the silencer foundation should be flat and compacted, installed firmly, with room for movement to avoid large vibrations; place two 5T beaters under the silencer, and install Y-direction guide devices and anti-backward limit devices on the beaters;

[0064] S11. When installing valves, check whether the valve switches are flexible and the indication is correct. Clean the valve thoroughly and keep it closed to prevent debris from entering. When welding valves, do not close them to prevent overheating and deformation. The inlet and outlet directions of the valves must be consistent with the direction indicated by the arrows on the valve body.

[0065] S12. Before pouring the main platform, plan the route of the blow pipe in advance and embed steel plates according to the route. Pour the blow pipe together with the platform. When constructing the blow pipe support, the I-beams can be directly welded to the embedded iron to enhance the strength of the support.

[0066] S13. Weld clamps on both sides of the support to better limit the reaction force, linear displacement and angular displacement of the steam flow during pipeline blowing; weld limiting supports at the outlet of the high-pressure main steam valve and reheat steam valve, and weld sliding supports at the intermediate pipe section.

[0067] S14. When fabricating the support, leave an appropriate expansion gap on the left, right and top sides of the pipe and the support. The temporary support is only allowed to expand in the direction of steam flow and is not allowed to move in the opposite direction. During the blowing process, carefully observe the load-bearing condition of the pipe and the support and check the free expansion of the pipe.

[0068] S15. The steam pipeline is purged in two stages. The first stage of purging adopts a pressure-stabilizing purging method. As the separator pressure gradually rises, the temporary control valve is gradually opened. When the separator pressure rises to 7.5MPa, the steam flow rate reaches 920-1000t / h, and the first stage of purging begins. The first stage of pressure-stabilizing purging is performed once. After 1-2 hours of pressure stabilizing purging, the main steam temporary control valve is gradually closed. The separator pressure is reduced to 5.0MPa, and the bypass pipeline is purged once. After the above purging is completed, the boiler is shut down according to the normal shutdown procedure.

[0069] S16. After the first stage of pressure stabilization and blowdown shutdown, the particle collector shall be removed during this period, and the system shall be restored to prepare for the second stage of blowdown. Depending on the water quality, it shall be decided whether to drain all water. If water is drained, the condenser, deaerator, condensate pump inlet filter, and feedwater pump inlet filter shall be manually cleaned.

[0070] S17. After the particle collector is removed, the second stage of steam blowing begins; the second stage of steam blowing adopts a pressure-stabilized steam blowing method. As the separator pressure gradually rises, the temporary control valve gradually opens. When the separator pressure rises to 7.5MPa, the steam flow rate reaches 920-1000t / h, and the second stage of steam blowing begins. After stabilizing the pressure and blowing for 1-2 hours, the target plate is replaced using a pressure-reducing steam blowing method. If the target plate is qualified, the combustion rate is gradually reduced, the temporary control valve for steam blowing is closed, and the separator pressure is reduced to 5.0MPa. The bypass pipeline is then purged once. After the steam blowing is completed, the boiler is shut down according to the normal shutdown procedure.

[0071] S18. After the blowdown is completed, wait for the system temperature to drop below the safe temperature, dismantle the temporary system and restore the pipeline according to the requirements of the formal system. Each weld joint should be supervised and inspected by four parties and recorded with signatures.

[0072] The following steps are required when hoisting and installing pipe elbows:

[0073] S1. First, install the temporary pipeline construction platform for steam purging of thermal power unit at the elbow. Then, move the top plate to the top of the elbow joint and use the lifting equipment to lower the elbow onto the lower arc plate 11. Then, fix the elbow with the upper arc plate 11.

[0074] S2. Move the second displacement block 10 to align the lower end of the elbow with the pipe. After alignment, perform welding. Once welding is complete, remove the upper and lower arc plates.

[0075] The commonly used target plate devices described above include flange-mounted direct-shaft type, manual tandem-shaft type, and pneumatic type. Flange-mounted direct-shaft target plate devices require a long time to disassemble the flange and replace the target plate, and the control door must have good airtightness to prevent gas leaks and injuries. Manual tandem-shaft type target plates require sufficient space on both sides of the pipeline for replacement, have a long replacement time, and result in significant steam leakage. Pneumatic target plate devices use a drive cylinder piston to move the target plate shaft up and down, causing steam leakage when passing through the bushing. The purging target plate uses a self-developed fully sealed safety target plate device. This device remotely controls the insertion and removal of the target plate. By adding a sealing valve between the target plate frame and the purging pipeline, the steam pipeline is completely isolated from the target plate device when removing the target plate, avoiding the safety hazard of steam leakage and burns to construction personnel during target plate replacement, greatly improving the operating efficiency and safety of the target plate device.

[0076] In the above description, when pre-embedding the support base, the previous steam blowing pipe supports were fixed to the main unit platform foundation or nearby beams and columns using expansion bolts. The fixing force was too small, and the expansion bolts were often pulled out during the blowing process, causing deformation of the supports and pipes, which endangered the safe operation of the unit. In order to ensure the strength and adhesion of the supports and the connection method with the foundation, the route of the blowing pipe was planned in advance before the main unit platform was poured, and steel plates were pre-embedded according to the route and poured together with the platform. During the construction of the blowing pipe supports, the I-beams and embedded iron can be directly welded to enhance the strength of the supports.

[0077] This invention adopts BIM modeling and modular assembly to optimize the construction process, greatly reducing the dangers of cross-operations and high-altitude operations, and effectively ensuring construction safety. By adding a sealing valve between the target plate frame and the purging pipe, the steam pipe is completely isolated from the target plate device when the target plate is removed, avoiding the safety hazard of steam leakage and burns to construction personnel during target plate replacement. It is convenient to use, simple to operate, and easy to promote.

Claims

1. A purging method for a pipeline construction platform for a thermal power unit, comprising a pipeline construction platform for a thermal power unit, the pipeline construction platform for a thermal power unit comprising a support (1), a support plate (3), a lower arc plate (11) and an upper arc plate (12), wherein there are four supports (1), and a support plate (3) is provided between the supports (1), a first support column (5) is passed through both ends of the support plate (3), and a reinforcing plate (6) is provided at the ends of the two first support columns (5), a first displacement block (7) is slidably connected on the reinforcing plate (6), a second support column (8) is passed through the first displacement block (7), a top plate (9) is provided at the top of the second support column (8), a second displacement block (10) is slidably connected to the top plate (9), a lower arc plate (11) is provided at the top of the second displacement block (10), and a lower arc plate (11) is provided above the lower arc plate (11). An upper arc plate (12) is provided; a crossbar (2) is provided between the brackets (1), and the support plate (3) is fixedly connected to the crossbar (2) by a clamp (4); the first support column (5) is fixedly connected to the support plate (3) by bolts, and the reinforcing plate (6) is located outside the bracket (1) and is fixedly connected to the first support column (5) by bolts; there are two top plates (9), which are located above the bracket (1), and the second support column (8) is fixedly connected to the first displacement block (7) by bolts, and the second displacement block (10) is fixedly connected to the top plate (9) by bolts; both ends of the lower arc plate (11) are provided with screws (13), the upper arc plate (12) passes through the screws (13), and a matching nut is screwed at the end of the screws (13), characterized in that, Includes the following steps: S1. Prepare the materials required for construction and inspect them. Since most of the materials are reused, and most pipe fittings have straight sections of varying lengths, a multi-functional elbow measuring ruler is needed to quickly measure the bending radius and straight section length of the elbows. S2. Use BIM modeling technology to check the temporary pipeline installation route and input the actual length data of each material into BIM. By simulating the assembly of different materials in BIM, the goal is to make reasonable secondary use of each material. After modeling is completed, each module is pre-assembled on the ground. The pipeline is divided into different pipe segment modules according to the actual situation, and each pipe segment module is numbered for on-site installation. S3. Cut materials according to module dimensions using a full-diameter multi-purpose plasma pipe beveling machine to cut bevels; before pipe construction, clearly explain the direction and amount of thermal expansion of the entire pipe section, and thoroughly clean the inside of the pipe; during butt jointing, use pipe alignment tools for quick alignment; pipe sections 10-15mm from the weld edge should be thoroughly derusted and oil-free to expose the metallic luster; temporary pipes should be naturally aligned with dummy valves and permanent pipes, and forced alignment is not allowed; S4. In front of the target plate, all temporary pipes should be internally derusted to ensure that the inside of the pipes is clean and free of debris. All welding should be done with argon arc welding for the root pass. After welding, the weld joint should be heat treated. During heat treatment, no external force should be applied to the vicinity of the weld joint or the pipe. S5. Disconnect the four main steam drain pipes and the one drain pipe before the high-pressure bypass valve between the manual valve and the pneumatic drain valve, connect them to a temporary pipe and connect them to the high-pressure side of the φ159x7 drain header pipe along with the two drain pipes before the temporary control valve, and discharge them to the outside of the turbine hall expansion end; disconnect the four high-temperature reheat steam drain pipes and the four low-temperature reheat steam drain pipes between the manual valve and the pneumatic drain valve, connect them to the low-pressure side of the φ159x7 drain header pipe along with the drain pipe before the particle collector, discharge them to the outside of the turbine hall expansion end and reinforce them, the wall thickness should not be less than 6mm, and the slope of the temporary drain pipe should be 3‰; S6. The target plate of the temporary exhaust pipe shall be installed on the straight pipe section, with the straight pipe section before and after the installation being no less than 5 meters, and close to the permanent pipe. The target plate device shall be installed on the straight pipe section of the temporary pipe and close to the end of the permanent pipe. The length of the straight pipe section before the device shall be no less than 5 times the pipe diameter, and the length of the straight pipe section after the device shall be no less than 3 times the pipe diameter. S7. When installing drain pipes, their layout and direction should be reasonable, and they should have a slope of 3‰; all drain pipe interfaces to the turbine drain expansion tank should be completely isolated during the blowdown process. S8. Install one 0-1MPa pressure measuring point and one 0-600℃ temperature measuring point 500mm away from the exhaust port on the temporary exhaust pipe, and lead the signals to the DCS for easy observation and recording; S9. Erect two frames around the target plate location; Dimensions of the target plate inspection platform: 3 meters wide, 4 meters long, and 1.2 meters above the target plate axis. Ramps are erected on both sides to facilitate personnel going up and down. S10. Erect scaffolding 10m long, 5m wide and 10m high around the silencer to prevent debris blown out of the blowpipe from splashing everywhere; the silencer and the external pipeline are hoisted and connected by a 25T truck crane; the silencer foundation should be flat and compacted, installed firmly, with room for movement to avoid large vibrations; place two 5T beaters under the silencer, and install Y-direction guide devices and anti-backward limit devices on the beaters; S11. When installing valves, check whether the valve switches are flexible and the indication is correct. Clean the valve thoroughly and keep it closed to prevent debris from entering. When welding valves, do not close them to prevent overheating and deformation. The inlet and outlet directions of the valves must be consistent with the direction indicated by the arrows on the valve body. S12. Before pouring the main platform, plan the route of the blow pipe in advance and embed steel plates according to the route. Pour the blow pipe together with the platform. When constructing the blow pipe support, the I-beams can be directly welded to the embedded iron to enhance the strength of the support. S13. Weld clips on both sides of the support to better limit the reaction force, linear displacement and angular displacement of the steam flow during pipeline blowing; Weld limit brackets at the outlets of the high-pressure main steam valve and reheat steam valve, and weld sliding brackets at the intermediate pipe section; S14. When fabricating the support, leave appropriate expansion gaps on the left, right and top sides of the pipe and the support. The temporary support is only allowed to expand in the direction of steam flow and is not allowed to move in the opposite direction. During the blowing process, carefully observe the load-bearing condition of the pipe and the support and check the free expansion of the pipe. S15. The steam pipeline is purged in two stages. The first stage of purging adopts a pressure-stabilizing purging method. As the separator pressure gradually rises, the temporary control valve is gradually opened. When the separator pressure rises to 7.5MPa, the steam flow rate reaches 920-1000t / h, and the first stage of purging begins. The first stage of pressure-stabilizing purging is performed once. After 1-2 hours of pressure-stabilizing purging, the main steam temporary control valve is gradually closed. The separator pressure is reduced to 5.0MPa, and the bypass pipeline is purged once. After the above purging is completed, the boiler is shut down according to the normal shutdown procedure. S16. After the first stage of pressure stabilization and blowdown shutdown, the particle collector shall be removed during this period, and the system shall be restored to prepare for the second stage of blowdown. Depending on the water quality, it shall be decided whether to drain all water. If water is drained, the condenser, deaerator, condensate pump inlet filter, and feedwater pump inlet filter shall be manually cleaned. S17. After the particle collector is removed, the second stage of steam blowing begins. The second stage of steam blowing adopts a pressure-stabilized steam blowing method. As the separator pressure gradually rises, the temporary control valve is gradually opened. When the separator pressure rises to 7.5MPa, the steam flow rate reaches 920-1000t / h, and the second stage of steam blowing begins. After stabilizing the pressure and blowing for 1-2 hours, the target plate is replaced by a pressure-reducing steam blowing method. If the target plate is qualified, the combustion rate is gradually reduced, the temporary control valve for steam blowing is closed, the separator pressure is reduced to 5.0MPa, and the bypass pipeline is purged once. After the steam blowing is completed, the boiler is shut down according to the normal shutdown procedure. S18. After the blowdown is completed, wait for the system temperature to drop below the safe temperature, dismantle the temporary system and restore the pipeline according to the requirements of the formal system. Each weld joint should be supervised and inspected by four parties and recorded with signatures.

2. The purging method for a pipeline construction platform of a thermal power unit according to claim 1, characterized in that: The following steps are required when hoisting and installing pipe elbows: S1. First, install a temporary pipeline construction platform for steam purging of thermal power unit at the elbow. Then, move the top plate to the top of the elbow joint and use the lifting tool to lower the elbow onto the lower arc plate (11). Then, fix the elbow with the upper arc plate (12). S2. Move the second displacement block (10) to align the lower end of the elbow with the pipe. After the alignment is completed, perform welding. After the welding is completed, remove the upper and lower arc plates.

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