1 Project Overview 1.1 System Introduction The high temperature and high pressure steam pipeline mainly includes the main steam pipeline system and the high and low temperature reheat steam pipeline system. This professional guide is applicable to the installation of the main steam pipeline, the installation of the high and low temperature reheat steam pipeline and the installation of the high and low pressure bypass pipeline . The main steam pipeline of this unit is led out from the outlet of the boiler superheater header, and is led from the steel pipe to the turbine room in two ways to connect to the main steam valve of the steam turbine system; the low temperature reheat pipeline leads from the high pressure cylinder into two ways back to the low temperature of the boiler Reheat header: The high temperature reheat steam pipeline is led out from the outlet of the boiler high temperature reheat header, and is connected to the automatic regulating door of the steam turbine system in two ways by the steel pipe before reaching the turbine room. In order to maintain the safe and stable operation of the boiler and achieve a stable steam pressure, a high-pressure bypass pipeline is provided on the main steam pipeline, and a low-pressure bypass pipeline is provided on the high-temperature reheat steam pipeline. The bypass system starts and stops the unit And variable load operation plays an important role. 1.2 Main system parameters The design pressure of the main steam pipeline is P=13.7Mpa, the design temperature is t=545℃, and the main material of the system is 12Cr1MoV φ377×50 alloy steel pipe. The design pressure of the low-temperature reheat steam pipeline is P=3.04755Mpa, the design temperature t=335.6℃, and the main material of the system is φ660.4×17.5 steel pipe of ST45.8/Ⅲ. The design pressure of the high-temperature reheat steam pipeline is P=2.58Mpa, the design temperature is t=545℃, and the main material of the system is 10CrMo910 φ609.6×20 alloy steel pipe. 1.3 System layout 1.3.1 Main steam pipeline: boiler superheater header outlet (elevation 44.54 meters) → right side of boiler at 37 meters elevation → 27 meters to 15.5 meters in front of the furnace → turbine room (divided into two pipelines with elevation 3.6 meters) → The high-pressure main door of the steam turbine system. 1.3.2 Low-temperature reheat steam pipeline: steam outlet of high-pressure cylinder of steam turbine (8.05m elevation) → turbine room (3.6m elevation) → 14.5m 27.98m layer in front of the furnace → boiler low-temperature reheater inlet header. 1.3.3 High-temperature reheat steam pipeline: boiler high-temperature reheater header outlet (45 meters above sea level) → the right side of the boiler with 39.6 meters above sea level → 39.6 meters to 19.6 meters in front of the furnace → turbine room (two roads with an elevation of 7.6 meters) →Automatically adjust the valve. 1.3.4 High-pressure bypass pipeline: the main steam pipeline in front of the furnace (elevation 15.5 meters) → high-pressure bypass valve (elevation 7.17 meters) → the low-temperature reheat pipeline between the turbines (elevation 3.6 meters). 1.3.5 Low-pressure bypass pipeline: the high-temperature reheat steam pipeline in front of the furnace (elevation 17.3 meters) → low-pressure bypass valve (elevation 7.5 meters) → condenser temperature and pressure reducing device (elevation 6 meters). 1.4 Main engineering volume 1.4.1 Main steam pipeline: total weight 43752Kg DN>80: the pipeline is 129 meters in total, 1 valve in total, and 19 sets of supports and hangers. DN≤80: The pipeline is 120 meters in total, 6 valves in total, and about 40 sets of supports and hangers. 1.4.2 High-temperature reheat steam pipeline: Total weight 22391Kg DN>80: The pipeline is 86.5 meters in total, 1 valve in total, and 13 sets of supports and hangers. DN≤80: The pipeline is 20 meters in total, 4 valves in total, and about 10 sets of supports and hangers. 1.4.3 Low-temperature reheat steam pipeline: total weight 30967Kg DN>80: 67 meters in total pipeline, 2 valves in total, and 10 sets of supports and hangers. DN≤80: There are a total of 100 meters of pipelines, a total of 4 valves, and about 40 sets of supports and hangers. 2 Compilation basis 2.1 Design drawings of Zhongnan Electric Power Design Institute: F0833S-J0501, F0833S-J0502, F0833S-J0503. 2.2 Pipeline DL5031-94 of “Technical Specifications for Construction and Acceptance of Electric Power Construction”. 2.3 Pipeline chapter of “Quality Inspection and Evaluation Standards for Thermal Power Construction”, 2000 edition. 2.4 “Metal Technology Supervision Regulations for Thermal Power Plants” SD107-83. 2.5 “Safety Work Regulations for Electric Power Construction” DL5009.1-2002. 2.6 “Administrative Regulations on Safe Construction of Electric Power Construction”. 3 Operation preparation and conditions 3.1 Operation preparation 3.1.1 The allocation of construction personnel: locksmith: 16; lifting worker: 3; manual worker: 6 people. 3.1.2 The equipment of main tools and tools: chain hoist; angle grinder; grinding wheel cutting machine; beveling machine; hoist; automatic gas cutting machine; spirit level; cutting torch; gantry crane; tank crane; dump truck; impact drill And so on, other machines and tools can be used flexibly according to needs. 3.1.3 The supply of power: oxygen, hydrocarbon gas, and argon gas are supplied in bottles or pipelines, and the construction power supply and electric welding machine are arranged in the combination yard, the main factory building (0 meters, 12 meters, 22 meters, etc.) and Boiler area. 3.1.4 Layout of the construction site: the inspection, cutting, processing, and prefabrication of pipes and fittings are mainly carried out in the pipeline assembly yard. 3.1.5 All construction personnel carefully study the work instructions before construction. 3.1.6 Before construction, all construction personnel are familiar with the construction drawings and on-site construction layout. 3.1.7 Before construction, all construction personnel are familiar with relevant regulations such as pipeline installation technical specifications, operating regulations, and quality acceptance standards. 3.1.8 Before construction, make the combined platform, combine the stool, the corresponding hoop and the welding shed. 3.2 Operating conditions 3.2.1 The materials must be checked and counted, the specifications and quantities must meet the design requirements, the materials must have a certificate of conformity, and the alloy materials must be subjected to spectral inspection before they can be used after they are qualified. 3.2.2 The appearance, wall thickness, metallography, and hardness of steel pipes shall be inspected piece by piece, and the original records shall be kept. 3.2.3 Materials should be waterproof and dustproof, stored separately and clearly marked. 3.2.4 Inconsistent quantities or defects of materials, etc., should be recorded in detail, and the situation should be reported to the technical staff. 3.2.5 The foundation has been checked and accepted, checked, and meets the conditions for security. 3.2.6 The hole through the wall has been inspected and verified that the position meets the design requirements. 3.2.7 The road for material transportation and placement is unobstructed, and the site is clean. 3.2.8 The construction site must have complete fire-fighting facilities. 3.2.9 Make preparations for the measurement and inspection records of all aspects of construction.
4 Operation steps and process requirements 4.1 Operation steps: 4.1.1 Support and hanger preparation: material requisition and inventory → support and hanger pipe preparation and root combination → support and hanger hanging and installation → support and hanger adjustment. 4.1.2 Pipeline installation: requisition and inventory of pipes and fittings→inspection of pipes and fittings (spectrum, thickness measurement, metallography, hardness, etc.)→cutting and groove processing→prefabricated assembly→hanging and installation. 4.1.3 Valve installation: use and check model → appearance inspection → disassembly inspection (spectral record) → hydraulic test and installation adjustment → inspection and cleaning. 4.2 Process requirements 4.2.1 Installation of the S hanger Ø The installation of the support hanger should be based on the position of the pipe, the elevation center and the horizontal center should be aligned, the rooting should be firm, and the connection with the pipe should be firm. Ø The hanger should be installed at the root according to the construction drawings, and the tie rods must be free from bending deformation, the ribs must be complete and well matched with the nuts, and the welding must be firm. Ø The opening of the lifting ring and backing plate at the root of the support and hanger should be made by mechanical drilling technology and cannot be cut with a cutting torch. Ø Pipe fixing brackets should be installed in strict accordance with the design drawings, and two or more fixing brackets shall not be installed on straight pipe sections without compensation devices at the same time. Ø In the laying of several parallel pipelines, the hanger rod of the bracket shall not lift any two pipelines with opposite displacement directions or different displacement values. Ø When temporary supports and hangers are used for pipeline installation, they should be clearly marked, and they should not conflict with the official supports and hangers. They should be removed after the pipeline installation and hydraulic test are completed. Ø When using expansion bolts to fix the roots of the support and hanger on the concrete foundation, the penetration of the expansion bolts must reach the specified depth value. Ø The sliding surfaces of the guide bracket and the sliding bracket should be clean and flat, and the movable parts such as balls, rollers, and supporting rollers should be in good contact with their supporting parts to ensure that the pipeline can expand freely. Ø All the movable parts of the movable support should be exposed and should not be covered by the thermal insulation layer. Ø For pipelines with thermal displacement, the following inspections and adjustments should be made to the supports and hangers in time when they expand due to heat. A: Whether the displacement direction, displacement and guiding performance of the movable support meet the design requirements. B: Whether the tube holder has fallen off. C: Whether the fixing bracket is firm and reliable. D: Whether the installation height of the spring bracket and the working height of the spring meet the design requirements. Ø The setting spring should be installed according to the design requirements. The fixing pin should be removed after the installation of the piping system, and the tightness test and heat preservation. The fixing pin should be completely drawn out and kept properly. Ø Constant force supports and hangers should be installed and adjusted according to design requirements. Ø After the support and hanger are adjusted, the screw threads of each connecting piece must be full, and the locking nut should be locked to prevent loosening. Ø The hole of the hanger bolt and the hole of the spring seat should meet the requirements. Ø The bracket spacing should be installed correctly according to the design requirements. 4.2.2 Pipeline assembly installation Ø The pipeline assembly should consider the convenience of pipe hoisting. Ø The piping assembly should have sufficient rigidity, no permanent deformation should occur after hoisting, and the temporary fixation should be firm and reliable. Ø Before the pipeline is assembled or the assembly is installed, the inside of the pipeline should be cleaned, no debris should be left in the pipeline, and temporarily blocked. Ø The slope direction and slope of the horizontal section of the pipeline should meet the design requirements. Ø The butt weld position of the pipe should meet the design requirements, otherwise it should meet the following requirements: 1) The distance between the weld position and the start point of the elbow shall not be less than the outer diameter of the pipe or not less than 100mm. 2) The distance between the two butt welds of the pipe should not be less than the outer diameter of the pipe and not less than 150mm. 3) The position of the pipe part of the support and hanger shall not overlap with the butt weld of the pipe, and the distance between the weld and the edge of the support and hanger shall not be less than 50mm. For the joints that require heat treatment after welding, the distance shall not be less than 5 times the width of the weld. 4) The pipe interface should avoid the opening positions of drainage, exhaust steam and instrument pipes, and the distance from the edge of the opening should not be less than 50mm. 5) When the pipe passes through the wall or floor, the pipe section located in the wall or floor must not have an interface.
Link to this article：Installation instructions for high-temperature and high-pressure steam pipelines
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