2MW backpressure steam turbine
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Construction Plan for NG/40/32/0 Turbine
Compiled by: Liu Mengliang
Reviewed by: Fitter Workshop of XXX Mechanical and Electrical Engineering Technology Company
July 9, 2004
Table of Contents
1. Overview ................................................................. 3
2. Basis for Compilation ................................................... 3
3. Preparations before Maintenance ...................................... 3
4. Construction Techniques ................................................... 3
5. Quality Standards for Maintenance ................................... 5
6. Quality Assurance Measures ............................................. 8
7. Commissioning and Acceptance ........................................... 8
8. Safety Measures ............................................................... 8
9. Common Technical Parameters ........................................... 11
10. Construction Tools and Materials ................................... 29
11. Construction Record Forms ........................................... 30
12. Appendix: Contents of Turbine Overhaul ......................... 31
Construction Plan for NG/40/32/0 Turbine
1. Overview
1.1 The NG/40/32/0 turbine is manufactured by Hangzhou Turbine Co., Ltd., and it is a back-pressure type horizontally split steam turbine. The unit consists of the outer and inner casings of the turbine, the nozzle chamber, the guide vane retainer rings, the labyrinth steam seal, the turbine rotor, the front and rear bearing housings along with the radial and thrust bearings, the control system, the safety system, the oil supply system, as well as auxiliary equipment. The main parameters of the turbine are shown in the table below: Table of Turbine Main Parameters. Driven machinery: Normal power – 3855 KW; Speed range – 5821–8149 r/min; Exhaust pressure range – 1.0–1.2 Mpa. Turbine number: Rated speed – 7761 r/min; Inlet pressure – 3.5/3.7 Mpa; Model: Maximum continuous speed – 8149 r/min; Inlet temperature – 420/430 °C; Rated power; Tripping speed – 8964 r/min; Exhaust pressure – 1.1 Mpa/1.2 Mpa. The scope of maintenance for this unit: Overhaul. 1.3 Direct cause of this maintenance: Excessive vibration at the front end of the compressor. 1.4 Key issues to be addressed during this maintenance: air leakage at the mid-plane of the turbine. 1.5 Key issues to pay attention to during this maintenance: If the pipelines of the compressor system need to be disassembled, and since the compressor is a relatively large-scale device, it is necessary to connect the first flanges at the compressor’s inlet and outlet only after the unit has been properly aligned, in order to avoid excessive pipeline forces from affecting the normal operation of the unit. 2. Basis for preparation: 2.1 General Provisions for the Installation, Construction and Acceptance of Mechanical Equipment (GB50231-98) ； 2.2 \"Procedures for the Maintenance and Overhaul of Power Plant Turbines\" (SHS 08001-92) 2.3 \"Certificate of Conformity for Turbine Products\" issued by Hangzhou Turbine Co., Ltd. 2.4 Documentation accompanying the equipment. 3. Preparation before maintenance 3.1 Organize maintenance personnel to study relevant materials, exchange experience in unit maintenance, and become familiar with the construction plan. 3.2 Carry out the preparation of materials (including supplies, spare parts, safety tools, construction equipment, etc.) and the preparation of the site for maintenance work. 3.3 Establish maintenance safety measures and a maintenance quality assurance system. 3.4 The person in charge of maintenance technology shall determine the construction methods and the person in charge of on-site operations; the construction logs filled out by the person in charge of on-site operations must be accurate and timely. 4. Construction procedures
4.1 Preparations before dismantling
4.1.1 All tools and equipment required for maintenance must be readily available; the overhead crane on site must pass the load test.
4.1.2 Power supply and gas supply must be cut off, and all necessary procedures such as draining must be carried out in accordance with regulations, so that conditions for maintenance are met. Only after obtaining a safety work permit can construction proceed. 4.2 Disassembly and Inspection 4.3.1 Remove all pipelines related to maintenance work and seal the pipe ends. 4.4 Remove the coupling cover, short circuits, and oil supply pipe. The oil supply pipe should be removed carefully, without causing any damage or bending. 4.5 Recheck the coaxiality of the unit. 4.6 Remove the governor section. 4.7.1 When removing and inspecting the cylinder bolts, special tools should be used to check for any defects on their surface, to determine their hardness, and to conduct non-destructive testing. 4.8 Disassembly of the cylinder 4.8.1 Insert the cat’s paw shims and cylinder guide rods. 4.8.2 Lift out the upper cylinder block and turn it over. 4.8.3 Check the cylinder split surface for defects such as cracks, erosion, damage, and signs of air leakage; if necessary, develop a repair plan and carry out the repairs accordingly. 4.9 Inspect the slide pin system and measure its clearance. 4.10 Check the torsional support for defects such as cracks and weld failures. 4.11 Remove and inspect the shaft displacement and shaft vibration probes. 4.12 Re-measure the clearances of the thrust pads, gas seal, nozzles, and moving blades. 4.13 Radial and thrust bearings 4.13.1 Remove the upper bearing housing, inspect the radial and thrust bearings, as well as check the clearance of these bearings. 4.13.2 Check whether the contact and wear on the working surfaces of each tile are uniform, and inspect the surface of the bearing alloy for defects such as excessive wear, electrocorrosion, cracks, inclusions, pores, and spalling. 4.13.3 Check whether there are any signs of wear on the inner and outer arcs of the tile body and on the pin holes, and whether the positioning pins are bent or loose. 4.13.4 Check the contact marks and remaining surface height of the thin-walled gasket. 4.14.2 Use specialized tools to lift the rotor horizontally. 4.14.3 Check the shaft journals, blades, shrouds, thrust discs, etc. for any damage, cracks, or other defects; perform non-destructive testing if necessary, and conduct blade frequency analysis. 4.14.4 Check the runout values of various parts of the rotor. 4.14.5 Check the meshing and wear condition of the governor drive gears. 4.14.6 Check the overspeed emergency trip device. 4.15 Diaphragms and nozzles 4.15.1 Check the difference in height between the cylinder and the diaphragm on the horizontal cross-section. 4.15.2 Check the axial clearance between the diaphragm and the cylinder, as well as the condition of the diaphragm support pins. 4.15.3 Remove the partition and inspect the partition labyrinth, ear screws, positioning keys, etc. 4.15.4 Inspect the corrosion, wear, erosion, and cracks of the first-stage baffle distributor as well as those of the baffles and nozzles in other stages, and replace them if necessary. 4.16 Steam seal 4.16.1 Check for wear, cracks, or damaged teeth on the steam seal; replace it if necessary. 4.16.2 Check the spring for cracks and damage, and verify that its elasticity is good. 4.17 Main steam valve, governor valve, and extraction control valve 4.17.1 Disassemble the main steam valve, governor valve, and extraction control valve. 4.17.2 Check the sealing condition between the valve head and seat, and verify whether the seal line remains intact. 4.17.3 Check the valve stem for defects such as bending, seizure, and cracks; repair or replace it if necessary. 4.17.4 Check the valve body and valve cover for cracks, as well as any damage to the contact surfaces. 4.17.5 Inspect and clean the filter screen of the main steam valve, as well as the labyrinth structure of the valve head assemblies of each valve itself. 4.18 Coupling 4.18.1 Use special tools to remove the coupling. 4.18.2 Clean and inspect the roughness and cylindricity of the inner bore of the coupling’s external gear ring as well as the outer circular surface of the shaft end, and measure the fit dimensions of each part. 4.18.3 Clean the shaft, external gear ring, and internal gear ring; check the contact area between the inner hole of the external gear ring and the shaft. 4.18.4 Check radial runout and end face runout. 4.19 Tumble dryer 4.19.1 Inspect and clean all components; replace oil seals, bearings, etc. as necessary. 4.19.2 Check the meshing of the turbine and worm; repair or replace them if necessary. 4.20 Condensing System 4.20.1 Remove the end cover of the condenser, clean it, inspect it; if necessary, perform a leak test or take appropriate actions. 4.20.2 Inspect the ejector nozzles and throats for erosion, cracks, and changes in geometric dimensions. 4.21 Steam extraction check valve. 4.21.1 Inspect and clean the check valve and its cylinder. 4.21.2 The cylinder plunger should be smooth without burrs, the plunger rod should be free of bending, and the “O”-ring seals must be reliable. 4.22 Atmospheric safety valve. Inspect the atmosphere safety valve disc and seat for corrosion, cracks, and sealing conditions. 5. Inspection and Maintenance Quality Standards 5.1 Couplings 5.1.1 Scratches and burrs on the inner surface of the external gear ring as well as on the outer surface of the shaft end must be removed by grinding, with the surface roughness not exceeding Ra0.4. 5.1.2 The fit dimensions and interference amounts of various parts shall comply with the standards specified by the manufacturer. 5.1.3 The radial runout value should be less than 0.03 mm, the end face runout value should be less than 0.02 mm, and the cylindricity deviation should be less than 0.03 mm. 5.1.4 When using hydraulic tools to disassemble and assemble keyless couplings, the maximum expansion oil pressure shall comply with the standards specified by the manufacturer. 5.1.5 The contact area between the inner hole of the external gear ring and the shaft shall be not less than 70% for keyed connections, and not less than 80% for keyless connections; poor contact shall be rectified through lapping. 5.2 Cylinders 5.2.1 After the turbine is shut down, the oil system should continue to operate until the temperature of the cylinder body drops below 60°C before it is stopped. 5.2.2 The insulation layer may be removed only when the temperature of the high-pressure cylinder drops to 150°C. When the insulation layer is in good condition, at an ambient temperature of 25°C, the temperature on the outer surface of the insulation layer should not exceed 50°C. 5.2.3 Schematic diagram of the slip pin system for single-cylinder steam turbines: 5.2.4 The position of the flexible support in the cold state shall conform to the dimensions specified in the diagram. 5.2.5 On the cylinder mating surface, if there are signs of erosion caused by air leakage, surface repair techniques such as plasma spray welding can be used. After repair, the number of grinding spots per 25×25 mm area should be between 20 and 25, and the surface roughness should not exceed Ra0.8. 5.2.6 After tightening 1/3 of the bolts without applying any coating, a feeler gauge with a thickness of 0.03 mm must not be able to be inserted at the high-pressure cylinder; in those areas where it is possible to insert such a gauge, the depth of insertion shall not exceed 1/3 of the effective sealing width of the cylinder joint. 5.2.7 When the cylinders are fastened together, a sealing coating such as refined linseed oil should be applied to the mid-surface; the coating should be applied evenly, with a thickness of generally 0.5 mm. 5.3 Bolts 5.3.1 The cylinder block bolts are generally removed in the order of low-pressure section, medium-pressure section, and high-pressure section; the tightening order is reversed, with two bolts being tightened symmetrically each time. The order of bolt tightening is shown in the diagram. 5.3.2 Bolt tightening is divided into pre-tightening and final tightening ； The final tightening of large-diameter bolts should be carried out using thermal tightening ； During pre-tightening, use a special wrench to tighten the bolts and set the zero position; then, according to the rotation arc length specified in the table, make marks on the corresponding parts of the cylinder. Once the bolts are heated, tighten them to the designated position ； Small-diameter bolts can be tightened directly to the specified position without heating. 5.3.3 Bolts and nuts shall undergo non-destructive testing to confirm the absence of cracks; if necessary, metallographic analysis and mechanical property tests shall be conducted. 5.3.4 Measure the hardness of the bolts; when the hardness of the bolts and nuts is 10% lower than the specified value, they should be replaced. 5.3.5 The threaded portion of the bolt shall be coated with a high-temperature anti-seize agent (usually molybdenum disulfide). After tightening, the distance between the top of the bolt and the top of the nut shall be no less than 5 mm. 5.4 Bearings 5.4.1 Thrust bearings 5.4.1.1 If the bearing alloy contains inclusions, pores, flaking, or peeling, it should be replaced. 5.4.1.2 The tile and positioning pin must not come apart. 5.4.1.3 The thickness of the tiles should be uniform; the maximum difference in thickness among the tiles shall not exceed 0.01 mm or meet the requirements specified in the drawings; otherwise, they should be replaced. 5.4.1.4 Place the bearing housing in its assembled position and check it; the axial clearance should not exceed 0.05 mm. If this value is exceeded, the thickness of the housing’s axial positioning ring should be adjusted, but care must be taken not to make it too tight. 5.4.1.5 The clearance of the thrust bearing and the clearance of the oil baffle shall comply with the specifications in the table; otherwise, adjustments or replacement shall be carried out. 5.4.1.6 The surface roughness of the thrust plate shall not be greater than Ra0.2. 5.4.1.7 The parallelism deviation between the two end surfaces of the thrust plate shall be less than 0.01 mm. 5.4.2 Radial bearings 5.4.2.1 Measure the thickness of the bearing shells; the thickness variation within the same set of shells should be kept within 0.01 mm. 5.4.2.2 If the babbitt layer contains slag inclusions, pores, signs of electrocorrosion, etc., it should be replaced. 5.4.2.3 The contact angle of thin-walled tiles should be within the range of 60–90°, with a maximum of 120°; otherwise, they should be adjusted. 5.4.2.4 There should be a interference fit of 0.000–0.015 mm between the thin-walled tile and its socket. 5.4.2.5 The radial bearing clearance value shall meet the requirements specified in the Turbine Product Certificate of Conformity. 5.5 Rotor 5.5.1 The straightness deviation of the shaft shall not exceed 0.025 mm; otherwise, it should be straightened or replaced with a new one. 5.5.2 The roundness deviation of the shaft journal shall not exceed 0.02 mm, the cylindricity deviation shall also not exceed 0.02 mm, and the surface roughness shall not be greater than Ra0.4. 5.5.3 The end-face and radial runout values of the thrust disc shall be less than 0.015 mm. 5.5.4 Requirements for journal camber: The camber of the front journal in a single-cylinder turbine should be less than 0.05 mm/m, while the camber of the rear journal should be zero, or it should bulge backward by no more than the amount that the front journal bulges forward. 5.5.5 If the blades are damaged or have curled edges, and if cracks or other defects are detected in the blades or blade roots through non-destructive testing, they should be repaired or replaced. 5.5.6 After cleaning the rotor, it is necessary to conduct a dynamic balance test together with the outer gear ring of the coupling; the standards for dynamic balance shall follow the relevant provisions specified in the accompanying documentation. 5.5.7 Unit alignment: The alignment shall be carried out in accordance with the instructions provided by the manufacturer of the driven equipment, and the deviation between the final alignment curve and the cold-state curve adjusted for ambient temperature shall not exceed 0.05 mm. 5.6 Diaphragms 5.6.1 When severe erosion of the stationary diaphragm blades or cracking of the root welds is observed, repair or replacement is required. 5.6.2 The maximum height difference between the cylinder and the mid-plane of the partition (the partition should be lower than the cylinder) shall be greater than 0.10 mm. 5.6.3 The axial clearance between the diaphragms and the diaphragm grooves is generally: 0.05–0.10 mm for welded steel diaphragms, and 0.10–0.20 mm for cast iron diaphragms; the radial clearance is generally 0.05–0.20 mm. 5.6.4 The clearance between the impeller, nozzles, and diaphragms shall meet the requirements specified in the “Certificate of Conformity for Steam Turbine Products”. 5.7 Steam seal 5.7.1 The top of the steam seal piece should be sharp; it must not have any defects such as notches or misalignment, otherwise it should be repaired or replaced. 5.7.2 Springs (sheets) that lack sufficient elasticity, have cracks, or other damage should be replaced. 5.7.3 The steam seal clearance shall meet the requirements specified in the Turbine Product Certification Certificate; if the local clearance is too small, a special scraper can be used to adjust it ； When the steam seal clearance is out of tolerance, repair or replacement can be carried out by peening and scraping the protruding shoulder on its back. 5.8 Control System 5.8.1 When defects such as scoring, dents, wear, corrosion, and cracks occur on the valve stems, valve discs, and valve seats of the main steam valve, throttle valve, and extraction control valve, they shall be repaired or replaced. 5.8.2 The straightness deviation of the valve stem shall be less than 0.015 mm. 5.8.3 Use the rubbing method to check that the contact line between the valve head and the valve seat is intact and uninterrupted, with the width of the contact line not exceeding 1.5 mm. 5.8.4 The allowable gap between the valve stem and the bushing is 0.10–0.13 mm, with a maximum value not exceeding 0.20 mm. 5.8.5 The dimensions of the connecting rods in various parts of the control system shall comply with the specifications provided by the manufacturer. 5.8.6 Adjust the speed control system and protective devices and conduct characteristic tests in accordance with the manufacturer’s specifications. 5.8.7 The governor should be replaced when necessary, and the newly installed governor must be calibrated to specification by a professional manufacturer. 5.8.8 The control needle valve of the ASKANIA regulator should be unobstructed ； The balance spring should not be detached or broken ； The bellows linkage mechanism should be free of damage, and the hard-feedback setter should have reliable performance; otherwise, it should be repaired or replaced. 5.9 The maintenance methods and quality standards for the turning device shall refer to SHS01028—92 \"Maintenance Procedures for Gearboxes\". 5.10 Condensate System 5.10.1 The inspection methods and quality standards for condensers shall refer to SHS01009—92 \"Maintenance and Inspection Procedures for Shell-and-Tube Heat Exchangers\". 5.10.2 The maintenance methods and quality standards for the condensate pump shall refer to SHS01013—92 \"Maintenance and Repair Procedures for Centrifugal Pumps\". 5.10.3 The exhaust pump nozzle should be replaced if its diameter exceeds the design value by 0.5 mm. 5.10.4 The repair and acceptance of the exhaust cooler shall be carried out in accordance with SHS01009—92 \"Maintenance and Repair Procedures for Shell-and-Tube Heat Exchangers\". 5.11 Oil System 5.11.1 The repair and acceptance of seal oil pumps and lubricating oil pumps shall be carried out in accordance with SHS01016—92 \"Maintenance and Repair Procedures for Screw Pumps\" and SHS01013—92 \"Maintenance and Repair Procedures for Centrifugal Pumps\". 5.11.2 Clean the fuel tank, fuel lines, fuel filters, six-way valves, etc., and repair or replace components as necessary. 5.11.3 Circulate and filter or replace the turbine oil; the quality of the oil shall meet the relevant standards specified in the accompanying documents. 5.11.4 After inspection and cleaning, the accumulator capsule shall be pressurized to 0.2 Mpa; it is considered qualified if the pressure remains unchanged after being held at this level for 30 minutes. 5.12 Extraction check valve. The check valve should be flexible and reliable, with a tight seal when closed ； The cylinder plunger should be smooth; any burrs must be ground and polished, with a surface roughness of no more than Ra0.4. The straightness deviation of the plunger rod should be less than 0.02 mm, and all \"O\"-rings must be replaced. 5.13 Atmospheric safety valve: The valve disc and seat of the atmospheric safety valve shall be free from defects such as corrosion and cracks. The surface roughness of the valve seat should not exceed Ra1.6; the actuator should function smoothly, and the water inlet pipe should be unobstructed; otherwise, it should be repaired or replaced. 5.14 Others 5.14.1 High-pressure steam pipes, flanges, and elbows shall be free from defects such as cracks and sand holes; thickness measurements of the pipes shall be taken, and the reduction in wall thickness shall be less than 1/4 of the original wall thickness; otherwise, they shall be repaired or replaced. 5.14.2 The flange grooves of high-pressure pipes and the elliptical steel gaskets should be lapped against each other, with a complete contact line. 5.14.3 Pipe supports and hangers shall be firm and reliable. 5.14.4 The valves of various systems shall be inspected carefully based on their operating conditions, and disassembled for repair or replaced if necessary. 6. Quality assurance measures 6.1 The technical instructions must be detailed and thorough; all construction workers must operate with valid certificates, and they must be fully familiar with the construction site, the construction design drawings, and the construction measures prior to starting work. 6.2 Maintenance shall be carried out strictly in accordance with the manufacturer’s technical standards, and in compliance with the provisions of the \"Code for Maintenance and Repair of Petrochemical Equipment\". 6.3 When removing the fastening bolts of the equipment’s cover, a special wrench must be used; it is not allowed to use inappropriate tools to force the removal. 6.4 When placing large components after disassembly, wooden materials such as planks should be used as a base; ordinary accessories should be stored on shelves lined with rubber, and not placed directly on the ground. 6.5 When lifting various components, do so smoothly and steadily at a slow speed. Use a winch with an appropriate capacity attached to the rope loops in order to adjust the length; for ropes that come into direct contact with the surface of the components, use soft lifting straps or steel cables equipped with protective covers. 6.6 When lifting or reinstalling the large cover of the unit, the guide rods must be installed before any lifting operations can be carried out. 6.7 During assembly, all parts must be glued together with flour to ensure cleanliness; care should be taken when applying grease to the areas that require it. 6.8 For equipment stored outdoors, take proper measures to protect the finished products by implementing Moisture resistance and waterproofing actions ； Equipment and components that cannot be installed in a timely manner must be properly stored to prevent deformation, damage, rust, disarray, or loss. 7. Commissioning and acceptance 7.1 Preparations before commissioning 7.1.1 Verify that all maintenance work has been completed, maintenance records are complete, the quality of the maintenance meets the requirements stipulated in Article 3, oil circulation tests have been passed, conditions for commissioning are met, and a comprehensive commissioning plan is in place. 7.1.2 Start the lubricating oil pump, check whether the oil pipes, coupling covers, and oil seal rings are leaking oil, and take action if necessary. 7.1.3 Verify the oil supply to each lubrication point through the sight glass. 7.1.4 Check that the reset lever operates accurately ； Press the shutdown button and recheck the performance of the emergency trip mechanism. 7.1.5 The safety accessories have passed inspection, are complete and intact; the interlock and alarm system is sensitive and reliable. 7.1.6 Check whether the indication of the cylinder expansion gauge is at zero. 7.1.7 Check whether the turning gear rotates smoothly and freely, and check whether there are any abnormal noises from the rotor. 7.1.8 Warm up the machine in accordance with the manufacturer’s instructions, and check whether the cylinder expansion value matches the data measured before shutdown. 7.2 Commissioning and acceptance criteria 7.2.1 Start up and commissioning shall be carried out in accordance with the operating procedures provided by the manufacturer; during low-speed operation, there should be no abnormalities in the acoustic response, and it shall be checked that the cylinder expansion meets the requirements. 7.2.2 After confirming that there are no abnormalities at the rated speed, conduct an overspeed test. During the overspeed test, the governor and control lever should be disengaged; the speed of the turbine is increased by adjusting the opening of the main steam valve. When the speed reaches 110±1% of the maximum continuous speed, the emergency safety device activates and the turbine stops ； If the tripping speed does not meet the requirements, the machine should be stopped immediately and the flyweight spring adjusted again. The overspeed test should be conducted 3 times; the speed for each test cycle must remain within the specified range, with the maximum deviation between the speeds of the 3 cycles being no more than 1%. 7.2.3 The shaft vibration of the turbine rotor shall not exceed the value of LV calculated by the following formula, or 0.05 mm, whichever is smaller: LV = (12000/N)1/2 × 0.0254. Here, LV represents the maximum amplitude value (peak-to-peak), in mm; N is the maximum continuous rotational speed, in r/min. The shaft displacement shall meet the design specifications. 7.2.4 There are no leaks in the oil, water, and steam pipelines as well as in the valves. 7.2.5 The lubricating oil pressure and the speed control oil pressure meet the specifications set by the manufacturer; the lubricating oil temperature should be maintained within the range of 40±2°C. The temperature of the oil returning to the bearings should not exceed 65°C, while the temperature of the bearing shells should not exceed 70°C. 7.2.6 The speed control system operates smoothly. 7.2.7 Connect the couplings and conduct a load test; the turbine should reach the rated load. 7.3 Acceptance: Once the trial operation is successful and the equipment meets the required standards, the acceptance procedures shall be carried out. The technical documents for acceptance include: a. Maintenance records; b. Records of any major defects in the equipment, structural changes, system modifications, and replacement of components. c. Speed control system tuning records. d. Records of single-unit and combined commissioning tests. 8. Safety Measures 8.1 Construction workers shall wear appropriate personal protective equipment and work only with valid certificates; they must strictly comply with the relevant provisions of the \"Safety Technical Regulations for Petrochemical Construction\" (SH3505－99) during the construction process. 8.2 When lifting the equipment, ensure that the lifting ropes are securely fastened in the correct positions, with a sufficient safety factor ； The lifting station should be positioned accurately, and the legs must be firmly secured. A slinging rope must be used during lifting operations to prevent shaking and rotation. The command signals must be clear and accurate, and no one is allowed to stay or walk within the area where lifting is taking place. 8.3 Scaffolding should be erected at high-altitude work locations as needed for operations. 8.4 When using power tools, three-level protection must be implemented. 8.5 When aligning equipment, construction workers should regularly check whether the head of the hammer is secure, to prevent it from flying off and causing injury while hitting the shims. 8.6 Hazard analysis for maintenance operations is carried out as shown in the table below: Job Hazard Analysis (JHA) Form. Job/Task: Turbine maintenance. Area/Process: Analyst: Date: Month Day, 2004. Sequence Number, Work Steps, Hazards or Potential Incidents, Major Consequences, Existing Safety Controls, Probability (L), Severity (S), Risk Level (R), Recommended Corrective/Control Measures: 1. Determine the maintenance plan – The plan lacks HSE controls; equipment failures or injuries to personnel may occur. Relevant professionals should be organized to develop the plan. 1, 4, 4. The technician should carefully revise the plan. 2. Review the maintenance standards – Failure to review them as required may lead to poor equipment performance and equipment failures. Relevant regulations must be strictly followed. 3, 3, 9. 3. Prepare maintenance tools and assign personnel – Inappropriate tools may cause delays and financial losses. Workers must check the tools carefully. 2, 2, 4. Personnel may not have the necessary qualifications, which can affect the quality of maintenance, delay progress, and result in financial losses. Appropriate personnel should be selected. 2, 2, 4. 4. Fill out the maintenance work order properly – Failure to implement the safety measures specified in the work order may lead to equipment failures or injuries to personnel. Safety measures must be implemented. 1, 3, 3. The technician should supervise and inspect. 5. Disassemble and maintain the equipment – Failure to follow procedures may cause injuries to personnel or damage to the equipment. Maintenance must be carried out strictly in accordance with the plan. 2, 3, 6. The technician should supervise and inspect. 6. Monitor the quality of maintenance – Lack of strict oversight at the site may result in substandard equipment that does not meet usage requirements. Maintenance must be carried out strictly in accordance with the plan. 2, 4, 8. The technician should supervise and inspect. 8. Reassemble the equipment – Inadequate cooperation from workers may lead to injuries. Workers should remind each other during assembly. 2, 3, 6. The technician should supervise and inspect. 9. Testing – Failure to apply lubricant, incorrect rotation direction, or unsuitable testing conditions may cause equipment damage and prevent it from operating properly. Thorough inspections before testing are necessary; testing should only be carried out when all conditions are met. 1, 3, 3. 9. Common technical parameters – The following technical parameters are selected as control indicators for maintenance activities, based on the “General Provisions for the Installation, Construction, and Acceptance of Mechanical Equipment” (GB50231-98), the “Procedures for the Maintenance of Power Station Turbines” (SHS 08001-92), Hangzhou Turbine Co., Ltd.’s “Turbine Product Certification”, and other accompanying documentation related to the equipment. 1. Actual measurement of spindle positioning EI 113.60 EII 122.50 EIII 65.40 EIV 237.80 Axial positioning of the rotor in the cylinder (the axial clearance measurement values of all thrust bearing position benchmarks are expressed in the X+ direction and X- direction) Actual measurement X+ 2.8 X- 1.7 2. Installation guide front end (rear end symmetry) Front/rear Front/rear Front bearing seat Rear bearing seat Front cylinder Rear cylinder 3. Front steam seal assembly clearance requirements Actual measurement SR1 0.20-0.40 0.30 SR2 0.20-0.40 0.30 SA1 1.8-2.2 2.30 SA2 2.55-2.95 2.70 4. Front cylinder cat claw screw assembly clearance requirements Actual measurement S Left 0.11-0.22 0.20 Right 0.16 S1 Left ≥ 1.6 3.20 Right 2.80 S2 Left ≥ 23.6 25.5 Right 25.5 S3 Left 1.1-1.3 1.2 Right 1.2 L Left 25.1 Right 25.2 5. Front outer cylinder guide assembly clearance requirements Actual measurement S 0.01-0.03 0.02 6. Actual measured assembly clearance requirements for front bearing seat guide parts S 0.01-0.03 0.01 7. Actual measured assembly clearance requirements for front bearing seat connecting parts S Front left 0.025-0.035 0.03 Right 0.035 Rear left 0.025-0.035 0.035 Right 0.03 S1 Front left ≥ 1.6 6.2 Right 5.6 Rear left 5.9 Right 5.7 S2 Front left ≥ 22.7 21.9 Right 22.3 Rear left 22.1 Right 22.1 8. Actual measurement requirements for front bearing seat seal ring S 1.5-2.0 1.8 S1 0.043-0.119 0.08 9. Actual measurement requirements for front journal assembly clearance S 0.188-0.238 0.20 D 125 124.82 10. Thermal expansion indication requirements Actual measurement S 0.3-0.5 0.40 11. The thrust bearing assembly clearance requirements Actual measurement SA1 0.33-0.43 0.33 SR1 0.05-0.12 0.08 12. The emergency interrupter assembly clearance requirements Actual measurement R+ 0.8-1.2 1.15 R- 0.8-1.2 0.85 S 0.8-1.0 0.90 13. Actual measured assembly clearance requirements for bearing seat tie rod bolts S left 0.09-0.12 0.10 S right 0.10 14. Actual measured assembly clearance requirements for rear bearing seat guides S 0.01-0.03 0.02 15. Actual measured assembly clearance requirements for rear steam seal SR1 0.20-0.40 0.40 SR2 0.20-0.40 0.40 SA1 3.1-3.9 3.2 SA2 4.6-5.4 5.2 16. Actual measurement clearance requirements for rear cylinder cat claw bolt assembly S Left 0.11-0.22 0.12 Right 0.13 S1 Left 1.1-1.3 1.3 Right 1.3 L Left 11.2 Right 11.9 Seventeen. Actual measurement requirements for assembly clearance of rear cylinder adjustment components S 0.02-0.041 0.03 Eighteen. Actual measurement requirements for rear bearing seat seal ring S 3.2-3.7 3.6 S1 0.043-0.143 0.10 Nineteen. Actual measurement requirements for assembly clearance of rear journal S 0.188-0.238 0.205 D 125 124.81 20. Actual measurement requirements for assembly clearance of eccentric bolts S 0.02-0.029 0.02 21. Actual measurement requirements for manual turning device S+ 5-6 5.4 S- 3-4 3.5 Gasket front 2.4 rear 2.4 22. Actual measurement requirements for assembly clearance of vertical adjustment components S1 0.02-0.06 0.05 S2 0.11-0.17 0.15 23. Actual measurement of internal steam seal assembly clearance requirements SR1 0.30-0.56 0.38 SR2 0.50-0.76 0.6 SA1 1.7-2.3 1.7 SA2 2.7-3.3 2.9 24. Actual measurement of assembly clearance requirements for horizontal adjustment components S 0.025-0.06 0.05 25. Steam chamber assembly gap required measured S 0.02-0.06 0.045 26. Angle ring assembly clearance 1 required measured S1 0.07-0.12 0.12 0.12 0.12 0.12 S2 2.4-3.1 2.4 2.4 2.4 2.4 S3 ≥3.1 4.2 4.1 4.1 4.1 27. Angle ring assembly clearance 2 requires actual measurement S1 ≥0.8 2.8 2.9 2.9 2.9 S2 ≥1.0 2.8 2.8 2.8 2.8 S3 ≥1.25 3.0 3.1 3.0 2.9 28. Guide vane holding ring flow gap level SRLE SRLA SALE SALA Requirements for actual measurement Requirements for actual measurement Requirements for actual measurement Requirements for actual measurement 2/102 0.6-0.87 0.60 5.9 6.25 3/103 0.3-0.56 0.40 0.30-0.56 0.40 2.7 3.75 3.7 4.2 4/104 0.3-0.56 0.40 0.30－0.56 0.40 2.8 3.9 3.8 4.3 5/105 0.3－0.56 0.40 0.30－0.56 0.40 2.8 3.9 3.9 4.35 6/106 0.3－0.56 0.40 0.30－0.56 0.40 2.9 4.1 4.1 4.5 7/107 0.3－0.56 0.40 0.30－0.56 0.40 2.9 4.0 4.2 4.6 8/108 0.3－0.56 0.40 0.30－0.56 0.40 3.0 4.0 4.3 7. Construction machinery and materials No. Name Specification Quantity 1 Kerosene 200Kg 2 Sodium hydrogen phosphate 200Kg 3 Sandpaper 100# 100 sheets 600# 200 sheets 4 Copper sheet δ＝0.05 10Kg δ＝0.10 5Kg δ＝0.15 5Kg δ＝0.50 5Kg 5 Rag 100Kg 6 Plastic cloth white and transparent 200Kg Colored 100m2 7 Lithium-based 3# grease 10Kg 8 Molybdenum disulfide 20Kg 9 PTFE sealing tape 30 rolls 10 Sealant 704 glue 40 boxes 11 Sealant 604 glue 20 boxes 12 Copper rod φ30 1m φ50 1m 13 4 plastic basins 14 Asbestos cloth 30m2 15 Flour 200Kg 16 White solid cloth 50m 11. Construction record form 11.1 Machine disassembly and assembly clearance record 11.2 Machine coupling alignment record 11.3 Machine and equipment single unit test run record (1), Machine and equipment unit test run record (2) 12. Appendix 1: Steam turbine overhaul content 9.1 includes intermediate repair content 9.2 Dismantle and install cosmetic panels and insulation layers 9.3 Check whether the cylinder has cracks, erosion, damage, and whether there are any defects such as leakage marks on the joint surface, deal with it if necessary, check the sliding pin system and cylinder level 9.4 Inspection, Clean the partition and nozzle, adjust the clearance between each part of the partition 9.5 Check, clean or replace some air seals and springs, adjust the air seal gap 9.6 Replace all "O" rings 9.7 Check the rotor radial and end face runout values, shaft straightness, check blades, shrouds, rivets, etc. Whether there are looseness, cracks, fractures, corrosion and other defects, make necessary adjustments according to the specific situation. 9.8 Inspect, clean the cylinder bolts and nuts, and conduct non-destructive testing, and replace them if necessary. 9.9 Perform inspections on the speed governor, extraction regulator, emergency safety device and power transmission mechanism. Inspect, calibrate or replace new parts 9.10 Disassemble and inspect or repair the main air valve, speed control valve and air extraction valve, check the straightness of each valve stem, straighten or replace new parts if necessary 9.11 Inspect, clean the turning device system 9.12 Inspect, clean the fuel tank, energy accumulator, etc.
Compiled by: Liu Mengliang
Reviewed by: Fitter Workshop of XXX Mechanical and Electrical Engineering Technology Company
July 9, 2004
Table of Contents
1. Overview ................................................................. 3
2. Basis for Compilation ................................................... 3
3. Preparations before Maintenance ...................................... 3
4. Construction Techniques ................................................... 3
5. Quality Standards for Maintenance ................................... 5
6. Quality Assurance Measures ............................................. 8
7. Commissioning and Acceptance ........................................... 8
8. Safety Measures ............................................................... 8
9. Common Technical Parameters ........................................... 11
10. Construction Tools and Materials ................................... 29
11. Construction Record Forms ........................................... 30
12. Appendix: Contents of Turbine Overhaul ......................... 31
Construction Plan for NG/40/32/0 Turbine
1. Overview
1.1 The NG/40/32/0 turbine is manufactured by Hangzhou Turbine Co., Ltd., and it is a back-pressure type horizontally split steam turbine. The unit consists of the outer and inner casings of the turbine, the nozzle chamber, the guide vane retainer rings, the labyrinth steam seal, the turbine rotor, the front and rear bearing housings along with the radial and thrust bearings, the control system, the safety system, the oil supply system, as well as auxiliary equipment. The main parameters of the turbine are shown in the table below: Table of Turbine Main Parameters. Driven machinery: Normal power – 3855 KW; Speed range – 5821–8149 r/min; Exhaust pressure range – 1.0–1.2 Mpa. Turbine number: Rated speed – 7761 r/min; Inlet pressure – 3.5/3.7 Mpa; Model: Maximum continuous speed – 8149 r/min; Inlet temperature – 420/430 °C; Rated power; Tripping speed – 8964 r/min; Exhaust pressure – 1.1 Mpa/1.2 Mpa. The scope of maintenance for this unit: Overhaul. 1.3 Direct cause of this maintenance: Excessive vibration at the front end of the compressor. 1.4 Key issues to be addressed during this maintenance: air leakage at the mid-plane of the turbine. 1.5 Key issues to pay attention to during this maintenance: If the pipelines of the compressor system need to be disassembled, and since the compressor is a relatively large-scale device, it is necessary to connect the first flanges at the compressor’s inlet and outlet only after the unit has been properly aligned, in order to avoid excessive pipeline forces from affecting the normal operation of the unit. 2. Basis for preparation: 2.1 General Provisions for the Installation, Construction and Acceptance of Mechanical Equipment (GB50231-98) ； 2.2 \"Procedures for the Maintenance and Overhaul of Power Plant Turbines\" (SHS 08001-92) 2.3 \"Certificate of Conformity for Turbine Products\" issued by Hangzhou Turbine Co., Ltd. 2.4 Documentation accompanying the equipment. 3. Preparation before maintenance 3.1 Organize maintenance personnel to study relevant materials, exchange experience in unit maintenance, and become familiar with the construction plan. 3.2 Carry out the preparation of materials (including supplies, spare parts, safety tools, construction equipment, etc.) and the preparation of the site for maintenance work. 3.3 Establish maintenance safety measures and a maintenance quality assurance system. 3.4 The person in charge of maintenance technology shall determine the construction methods and the person in charge of on-site operations; the construction logs filled out by the person in charge of on-site operations must be accurate and timely. 4. Construction procedures
4.1 Preparations before dismantling
4.1.1 All tools and equipment required for maintenance must be readily available; the overhead crane on site must pass the load test.
4.1.2 Power supply and gas supply must be cut off, and all necessary procedures such as draining must be carried out in accordance with regulations, so that conditions for maintenance are met. Only after obtaining a safety work permit can construction proceed. 4.2 Disassembly and Inspection 4.3.1 Remove all pipelines related to maintenance work and seal the pipe ends. 4.4 Remove the coupling cover, short circuits, and oil supply pipe. The oil supply pipe should be removed carefully, without causing any damage or bending. 4.5 Recheck the coaxiality of the unit. 4.6 Remove the governor section. 4.7.1 When removing and inspecting the cylinder bolts, special tools should be used to check for any defects on their surface, to determine their hardness, and to conduct non-destructive testing. 4.8 Disassembly of the cylinder 4.8.1 Insert the cat’s paw shims and cylinder guide rods. 4.8.2 Lift out the upper cylinder block and turn it over. 4.8.3 Check the cylinder split surface for defects such as cracks, erosion, damage, and signs of air leakage; if necessary, develop a repair plan and carry out the repairs accordingly. 4.9 Inspect the slide pin system and measure its clearance. 4.10 Check the torsional support for defects such as cracks and weld failures. 4.11 Remove and inspect the shaft displacement and shaft vibration probes. 4.12 Re-measure the clearances of the thrust pads, gas seal, nozzles, and moving blades. 4.13 Radial and thrust bearings 4.13.1 Remove the upper bearing housing, inspect the radial and thrust bearings, as well as check the clearance of these bearings. 4.13.2 Check whether the contact and wear on the working surfaces of each tile are uniform, and inspect the surface of the bearing alloy for defects such as excessive wear, electrocorrosion, cracks, inclusions, pores, and spalling. 4.13.3 Check whether there are any signs of wear on the inner and outer arcs of the tile body and on the pin holes, and whether the positioning pins are bent or loose. 4.13.4 Check the contact marks and remaining surface height of the thin-walled gasket. 4.14.2 Use specialized tools to lift the rotor horizontally. 4.14.3 Check the shaft journals, blades, shrouds, thrust discs, etc. for any damage, cracks, or other defects; perform non-destructive testing if necessary, and conduct blade frequency analysis. 4.14.4 Check the runout values of various parts of the rotor. 4.14.5 Check the meshing and wear condition of the governor drive gears. 4.14.6 Check the overspeed emergency trip device. 4.15 Diaphragms and nozzles 4.15.1 Check the difference in height between the cylinder and the diaphragm on the horizontal cross-section. 4.15.2 Check the axial clearance between the diaphragm and the cylinder, as well as the condition of the diaphragm support pins. 4.15.3 Remove the partition and inspect the partition labyrinth, ear screws, positioning keys, etc. 4.15.4 Inspect the corrosion, wear, erosion, and cracks of the first-stage baffle distributor as well as those of the baffles and nozzles in other stages, and replace them if necessary. 4.16 Steam seal 4.16.1 Check for wear, cracks, or damaged teeth on the steam seal; replace it if necessary. 4.16.2 Check the spring for cracks and damage, and verify that its elasticity is good. 4.17 Main steam valve, governor valve, and extraction control valve 4.17.1 Disassemble the main steam valve, governor valve, and extraction control valve. 4.17.2 Check the sealing condition between the valve head and seat, and verify whether the seal line remains intact. 4.17.3 Check the valve stem for defects such as bending, seizure, and cracks; repair or replace it if necessary. 4.17.4 Check the valve body and valve cover for cracks, as well as any damage to the contact surfaces. 4.17.5 Inspect and clean the filter screen of the main steam valve, as well as the labyrinth structure of the valve head assemblies of each valve itself. 4.18 Coupling 4.18.1 Use special tools to remove the coupling. 4.18.2 Clean and inspect the roughness and cylindricity of the inner bore of the coupling’s external gear ring as well as the outer circular surface of the shaft end, and measure the fit dimensions of each part. 4.18.3 Clean the shaft, external gear ring, and internal gear ring; check the contact area between the inner hole of the external gear ring and the shaft. 4.18.4 Check radial runout and end face runout. 4.19 Tumble dryer 4.19.1 Inspect and clean all components; replace oil seals, bearings, etc. as necessary. 4.19.2 Check the meshing of the turbine and worm; repair or replace them if necessary. 4.20 Condensing System 4.20.1 Remove the end cover of the condenser, clean it, inspect it; if necessary, perform a leak test or take appropriate actions. 4.20.2 Inspect the ejector nozzles and throats for erosion, cracks, and changes in geometric dimensions. 4.21 Steam extraction check valve. 4.21.1 Inspect and clean the check valve and its cylinder. 4.21.2 The cylinder plunger should be smooth without burrs, the plunger rod should be free of bending, and the “O”-ring seals must be reliable. 4.22 Atmospheric safety valve. Inspect the atmosphere safety valve disc and seat for corrosion, cracks, and sealing conditions. 5. Inspection and Maintenance Quality Standards 5.1 Couplings 5.1.1 Scratches and burrs on the inner surface of the external gear ring as well as on the outer surface of the shaft end must be removed by grinding, with the surface roughness not exceeding Ra0.4. 5.1.2 The fit dimensions and interference amounts of various parts shall comply with the standards specified by the manufacturer. 5.1.3 The radial runout value should be less than 0.03 mm, the end face runout value should be less than 0.02 mm, and the cylindricity deviation should be less than 0.03 mm. 5.1.4 When using hydraulic tools to disassemble and assemble keyless couplings, the maximum expansion oil pressure shall comply with the standards specified by the manufacturer. 5.1.5 The contact area between the inner hole of the external gear ring and the shaft shall be not less than 70% for keyed connections, and not less than 80% for keyless connections; poor contact shall be rectified through lapping. 5.2 Cylinders 5.2.1 After the turbine is shut down, the oil system should continue to operate until the temperature of the cylinder body drops below 60°C before it is stopped. 5.2.2 The insulation layer may be removed only when the temperature of the high-pressure cylinder drops to 150°C. When the insulation layer is in good condition, at an ambient temperature of 25°C, the temperature on the outer surface of the insulation layer should not exceed 50°C. 5.2.3 Schematic diagram of the slip pin system for single-cylinder steam turbines: 5.2.4 The position of the flexible support in the cold state shall conform to the dimensions specified in the diagram. 5.2.5 On the cylinder mating surface, if there are signs of erosion caused by air leakage, surface repair techniques such as plasma spray welding can be used. After repair, the number of grinding spots per 25×25 mm area should be between 20 and 25, and the surface roughness should not exceed Ra0.8. 5.2.6 After tightening 1/3 of the bolts without applying any coating, a feeler gauge with a thickness of 0.03 mm must not be able to be inserted at the high-pressure cylinder; in those areas where it is possible to insert such a gauge, the depth of insertion shall not exceed 1/3 of the effective sealing width of the cylinder joint. 5.2.7 When the cylinders are fastened together, a sealing coating such as refined linseed oil should be applied to the mid-surface; the coating should be applied evenly, with a thickness of generally 0.5 mm. 5.3 Bolts 5.3.1 The cylinder block bolts are generally removed in the order of low-pressure section, medium-pressure section, and high-pressure section; the tightening order is reversed, with two bolts being tightened symmetrically each time. The order of bolt tightening is shown in the diagram. 5.3.2 Bolt tightening is divided into pre-tightening and final tightening ； The final tightening of large-diameter bolts should be carried out using thermal tightening ； During pre-tightening, use a special wrench to tighten the bolts and set the zero position; then, according to the rotation arc length specified in the table, make marks on the corresponding parts of the cylinder. Once the bolts are heated, tighten them to the designated position ； Small-diameter bolts can be tightened directly to the specified position without heating. 5.3.3 Bolts and nuts shall undergo non-destructive testing to confirm the absence of cracks; if necessary, metallographic analysis and mechanical property tests shall be conducted. 5.3.4 Measure the hardness of the bolts; when the hardness of the bolts and nuts is 10% lower than the specified value, they should be replaced. 5.3.5 The threaded portion of the bolt shall be coated with a high-temperature anti-seize agent (usually molybdenum disulfide). After tightening, the distance between the top of the bolt and the top of the nut shall be no less than 5 mm. 5.4 Bearings 5.4.1 Thrust bearings 5.4.1.1 If the bearing alloy contains inclusions, pores, flaking, or peeling, it should be replaced. 5.4.1.2 The tile and positioning pin must not come apart. 5.4.1.3 The thickness of the tiles should be uniform; the maximum difference in thickness among the tiles shall not exceed 0.01 mm or meet the requirements specified in the drawings; otherwise, they should be replaced. 5.4.1.4 Place the bearing housing in its assembled position and check it; the axial clearance should not exceed 0.05 mm. If this value is exceeded, the thickness of the housing’s axial positioning ring should be adjusted, but care must be taken not to make it too tight. 5.4.1.5 The clearance of the thrust bearing and the clearance of the oil baffle shall comply with the specifications in the table; otherwise, adjustments or replacement shall be carried out. 5.4.1.6 The surface roughness of the thrust plate shall not be greater than Ra0.2. 5.4.1.7 The parallelism deviation between the two end surfaces of the thrust plate shall be less than 0.01 mm. 5.4.2 Radial bearings 5.4.2.1 Measure the thickness of the bearing shells; the thickness variation within the same set of shells should be kept within 0.01 mm. 5.4.2.2 If the babbitt layer contains slag inclusions, pores, signs of electrocorrosion, etc., it should be replaced. 5.4.2.3 The contact angle of thin-walled tiles should be within the range of 60–90°, with a maximum of 120°; otherwise, they should be adjusted. 5.4.2.4 There should be a interference fit of 0.000–0.015 mm between the thin-walled tile and its socket. 5.4.2.5 The radial bearing clearance value shall meet the requirements specified in the Turbine Product Certificate of Conformity. 5.5 Rotor 5.5.1 The straightness deviation of the shaft shall not exceed 0.025 mm; otherwise, it should be straightened or replaced with a new one. 5.5.2 The roundness deviation of the shaft journal shall not exceed 0.02 mm, the cylindricity deviation shall also not exceed 0.02 mm, and the surface roughness shall not be greater than Ra0.4. 5.5.3 The end-face and radial runout values of the thrust disc shall be less than 0.015 mm. 5.5.4 Requirements for journal camber: The camber of the front journal in a single-cylinder turbine should be less than 0.05 mm/m, while the camber of the rear journal should be zero, or it should bulge backward by no more than the amount that the front journal bulges forward. 5.5.5 If the blades are damaged or have curled edges, and if cracks or other defects are detected in the blades or blade roots through non-destructive testing, they should be repaired or replaced. 5.5.6 After cleaning the rotor, it is necessary to conduct a dynamic balance test together with the outer gear ring of the coupling; the standards for dynamic balance shall follow the relevant provisions specified in the accompanying documentation. 5.5.7 Unit alignment: The alignment shall be carried out in accordance with the instructions provided by the manufacturer of the driven equipment, and the deviation between the final alignment curve and the cold-state curve adjusted for ambient temperature shall not exceed 0.05 mm. 5.6 Diaphragms 5.6.1 When severe erosion of the stationary diaphragm blades or cracking of the root welds is observed, repair or replacement is required. 5.6.2 The maximum height difference between the cylinder and the mid-plane of the partition (the partition should be lower than the cylinder) shall be greater than 0.10 mm. 5.6.3 The axial clearance between the diaphragms and the diaphragm grooves is generally: 0.05–0.10 mm for welded steel diaphragms, and 0.10–0.20 mm for cast iron diaphragms; the radial clearance is generally 0.05–0.20 mm. 5.6.4 The clearance between the impeller, nozzles, and diaphragms shall meet the requirements specified in the “Certificate of Conformity for Steam Turbine Products”. 5.7 Steam seal 5.7.1 The top of the steam seal piece should be sharp; it must not have any defects such as notches or misalignment, otherwise it should be repaired or replaced. 5.7.2 Springs (sheets) that lack sufficient elasticity, have cracks, or other damage should be replaced. 5.7.3 The steam seal clearance shall meet the requirements specified in the Turbine Product Certification Certificate; if the local clearance is too small, a special scraper can be used to adjust it ； When the steam seal clearance is out of tolerance, repair or replacement can be carried out by peening and scraping the protruding shoulder on its back. 5.8 Control System 5.8.1 When defects such as scoring, dents, wear, corrosion, and cracks occur on the valve stems, valve discs, and valve seats of the main steam valve, throttle valve, and extraction control valve, they shall be repaired or replaced. 5.8.2 The straightness deviation of the valve stem shall be less than 0.015 mm. 5.8.3 Use the rubbing method to check that the contact line between the valve head and the valve seat is intact and uninterrupted, with the width of the contact line not exceeding 1.5 mm. 5.8.4 The allowable gap between the valve stem and the bushing is 0.10–0.13 mm, with a maximum value not exceeding 0.20 mm. 5.8.5 The dimensions of the connecting rods in various parts of the control system shall comply with the specifications provided by the manufacturer. 5.8.6 Adjust the speed control system and protective devices and conduct characteristic tests in accordance with the manufacturer’s specifications. 5.8.7 The governor should be replaced when necessary, and the newly installed governor must be calibrated to specification by a professional manufacturer. 5.8.8 The control needle valve of the ASKANIA regulator should be unobstructed ； The balance spring should not be detached or broken ； The bellows linkage mechanism should be free of damage, and the hard-feedback setter should have reliable performance; otherwise, it should be repaired or replaced. 5.9 The maintenance methods and quality standards for the turning device shall refer to SHS01028—92 \"Maintenance Procedures for Gearboxes\". 5.10 Condensate System 5.10.1 The inspection methods and quality standards for condensers shall refer to SHS01009—92 \"Maintenance and Inspection Procedures for Shell-and-Tube Heat Exchangers\". 5.10.2 The maintenance methods and quality standards for the condensate pump shall refer to SHS01013—92 \"Maintenance and Repair Procedures for Centrifugal Pumps\". 5.10.3 The exhaust pump nozzle should be replaced if its diameter exceeds the design value by 0.5 mm. 5.10.4 The repair and acceptance of the exhaust cooler shall be carried out in accordance with SHS01009—92 \"Maintenance and Repair Procedures for Shell-and-Tube Heat Exchangers\". 5.11 Oil System 5.11.1 The repair and acceptance of seal oil pumps and lubricating oil pumps shall be carried out in accordance with SHS01016—92 \"Maintenance and Repair Procedures for Screw Pumps\" and SHS01013—92 \"Maintenance and Repair Procedures for Centrifugal Pumps\". 5.11.2 Clean the fuel tank, fuel lines, fuel filters, six-way valves, etc., and repair or replace components as necessary. 5.11.3 Circulate and filter or replace the turbine oil; the quality of the oil shall meet the relevant standards specified in the accompanying documents. 5.11.4 After inspection and cleaning, the accumulator capsule shall be pressurized to 0.2 Mpa; it is considered qualified if the pressure remains unchanged after being held at this level for 30 minutes. 5.12 Extraction check valve. The check valve should be flexible and reliable, with a tight seal when closed ； The cylinder plunger should be smooth; any burrs must be ground and polished, with a surface roughness of no more than Ra0.4. The straightness deviation of the plunger rod should be less than 0.02 mm, and all \"O\"-rings must be replaced. 5.13 Atmospheric safety valve: The valve disc and seat of the atmospheric safety valve shall be free from defects such as corrosion and cracks. The surface roughness of the valve seat should not exceed Ra1.6; the actuator should function smoothly, and the water inlet pipe should be unobstructed; otherwise, it should be repaired or replaced. 5.14 Others 5.14.1 High-pressure steam pipes, flanges, and elbows shall be free from defects such as cracks and sand holes; thickness measurements of the pipes shall be taken, and the reduction in wall thickness shall be less than 1/4 of the original wall thickness; otherwise, they shall be repaired or replaced. 5.14.2 The flange grooves of high-pressure pipes and the elliptical steel gaskets should be lapped against each other, with a complete contact line. 5.14.3 Pipe supports and hangers shall be firm and reliable. 5.14.4 The valves of various systems shall be inspected carefully based on their operating conditions, and disassembled for repair or replaced if necessary. 6. Quality assurance measures 6.1 The technical instructions must be detailed and thorough; all construction workers must operate with valid certificates, and they must be fully familiar with the construction site, the construction design drawings, and the construction measures prior to starting work. 6.2 Maintenance shall be carried out strictly in accordance with the manufacturer’s technical standards, and in compliance with the provisions of the \"Code for Maintenance and Repair of Petrochemical Equipment\". 6.3 When removing the fastening bolts of the equipment’s cover, a special wrench must be used; it is not allowed to use inappropriate tools to force the removal. 6.4 When placing large components after disassembly, wooden materials such as planks should be used as a base; ordinary accessories should be stored on shelves lined with rubber, and not placed directly on the ground. 6.5 When lifting various components, do so smoothly and steadily at a slow speed. Use a winch with an appropriate capacity attached to the rope loops in order to adjust the length; for ropes that come into direct contact with the surface of the components, use soft lifting straps or steel cables equipped with protective covers. 6.6 When lifting or reinstalling the large cover of the unit, the guide rods must be installed before any lifting operations can be carried out. 6.7 During assembly, all parts must be glued together with flour to ensure cleanliness; care should be taken when applying grease to the areas that require it. 6.8 For equipment stored outdoors, take proper measures to protect the finished products by implementing Moisture resistance and waterproofing actions ； Equipment and components that cannot be installed in a timely manner must be properly stored to prevent deformation, damage, rust, disarray, or loss. 7. Commissioning and acceptance 7.1 Preparations before commissioning 7.1.1 Verify that all maintenance work has been completed, maintenance records are complete, the quality of the maintenance meets the requirements stipulated in Article 3, oil circulation tests have been passed, conditions for commissioning are met, and a comprehensive commissioning plan is in place. 7.1.2 Start the lubricating oil pump, check whether the oil pipes, coupling covers, and oil seal rings are leaking oil, and take action if necessary. 7.1.3 Verify the oil supply to each lubrication point through the sight glass. 7.1.4 Check that the reset lever operates accurately ； Press the shutdown button and recheck the performance of the emergency trip mechanism. 7.1.5 The safety accessories have passed inspection, are complete and intact; the interlock and alarm system is sensitive and reliable. 7.1.6 Check whether the indication of the cylinder expansion gauge is at zero. 7.1.7 Check whether the turning gear rotates smoothly and freely, and check whether there are any abnormal noises from the rotor. 7.1.8 Warm up the machine in accordance with the manufacturer’s instructions, and check whether the cylinder expansion value matches the data measured before shutdown. 7.2 Commissioning and acceptance criteria 7.2.1 Start up and commissioning shall be carried out in accordance with the operating procedures provided by the manufacturer; during low-speed operation, there should be no abnormalities in the acoustic response, and it shall be checked that the cylinder expansion meets the requirements. 7.2.2 After confirming that there are no abnormalities at the rated speed, conduct an overspeed test. During the overspeed test, the governor and control lever should be disengaged; the speed of the turbine is increased by adjusting the opening of the main steam valve. When the speed reaches 110±1% of the maximum continuous speed, the emergency safety device activates and the turbine stops ； If the tripping speed does not meet the requirements, the machine should be stopped immediately and the flyweight spring adjusted again. The overspeed test should be conducted 3 times; the speed for each test cycle must remain within the specified range, with the maximum deviation between the speeds of the 3 cycles being no more than 1%. 7.2.3 The shaft vibration of the turbine rotor shall not exceed the value of LV calculated by the following formula, or 0.05 mm, whichever is smaller: LV = (12000/N)1/2 × 0.0254. Here, LV represents the maximum amplitude value (peak-to-peak), in mm; N is the maximum continuous rotational speed, in r/min. The shaft displacement shall meet the design specifications. 7.2.4 There are no leaks in the oil, water, and steam pipelines as well as in the valves. 7.2.5 The lubricating oil pressure and the speed control oil pressure meet the specifications set by the manufacturer; the lubricating oil temperature should be maintained within the range of 40±2°C. The temperature of the oil returning to the bearings should not exceed 65°C, while the temperature of the bearing shells should not exceed 70°C. 7.2.6 The speed control system operates smoothly. 7.2.7 Connect the couplings and conduct a load test; the turbine should reach the rated load. 7.3 Acceptance: Once the trial operation is successful and the equipment meets the required standards, the acceptance procedures shall be carried out. The technical documents for acceptance include: a. Maintenance records; b. Records of any major defects in the equipment, structural changes, system modifications, and replacement of components. c. Speed control system tuning records. d. Records of single-unit and combined commissioning tests. 8. Safety Measures 8.1 Construction workers shall wear appropriate personal protective equipment and work only with valid certificates; they must strictly comply with the relevant provisions of the \"Safety Technical Regulations for Petrochemical Construction\" (SH3505－99) during the construction process. 8.2 When lifting the equipment, ensure that the lifting ropes are securely fastened in the correct positions, with a sufficient safety factor ； The lifting station should be positioned accurately, and the legs must be firmly secured. A slinging rope must be used during lifting operations to prevent shaking and rotation. The command signals must be clear and accurate, and no one is allowed to stay or walk within the area where lifting is taking place. 8.3 Scaffolding should be erected at high-altitude work locations as needed for operations. 8.4 When using power tools, three-level protection must be implemented. 8.5 When aligning equipment, construction workers should regularly check whether the head of the hammer is secure, to prevent it from flying off and causing injury while hitting the shims. 8.6 Hazard analysis for maintenance operations is carried out as shown in the table below: Job Hazard Analysis (JHA) Form. Job/Task: Turbine maintenance. Area/Process: Analyst: Date: Month Day, 2004. Sequence Number, Work Steps, Hazards or Potential Incidents, Major Consequences, Existing Safety Controls, Probability (L), Severity (S), Risk Level (R), Recommended Corrective/Control Measures: 1. Determine the maintenance plan – The plan lacks HSE controls; equipment failures or injuries to personnel may occur. Relevant professionals should be organized to develop the plan. 1, 4, 4. The technician should carefully revise the plan. 2. Review the maintenance standards – Failure to review them as required may lead to poor equipment performance and equipment failures. Relevant regulations must be strictly followed. 3, 3, 9. 3. Prepare maintenance tools and assign personnel – Inappropriate tools may cause delays and financial losses. Workers must check the tools carefully. 2, 2, 4. Personnel may not have the necessary qualifications, which can affect the quality of maintenance, delay progress, and result in financial losses. Appropriate personnel should be selected. 2, 2, 4. 4. Fill out the maintenance work order properly – Failure to implement the safety measures specified in the work order may lead to equipment failures or injuries to personnel. Safety measures must be implemented. 1, 3, 3. The technician should supervise and inspect. 5. Disassemble and maintain the equipment – Failure to follow procedures may cause injuries to personnel or damage to the equipment. Maintenance must be carried out strictly in accordance with the plan. 2, 3, 6. The technician should supervise and inspect. 6. Monitor the quality of maintenance – Lack of strict oversight at the site may result in substandard equipment that does not meet usage requirements. Maintenance must be carried out strictly in accordance with the plan. 2, 4, 8. The technician should supervise and inspect. 8. Reassemble the equipment – Inadequate cooperation from workers may lead to injuries. Workers should remind each other during assembly. 2, 3, 6. The technician should supervise and inspect. 9. Testing – Failure to apply lubricant, incorrect rotation direction, or unsuitable testing conditions may cause equipment damage and prevent it from operating properly. Thorough inspections before testing are necessary; testing should only be carried out when all conditions are met. 1, 3, 3. 9. Common technical parameters – The following technical parameters are selected as control indicators for maintenance activities, based on the “General Provisions for the Installation, Construction, and Acceptance of Mechanical Equipment” (GB50231-98), the “Procedures for the Maintenance of Power Station Turbines” (SHS 08001-92), Hangzhou Turbine Co., Ltd.’s “Turbine Product Certification”, and other accompanying documentation related to the equipment. 1. Actual measurement of spindle positioning EI 113.60 EII 122.50 EIII 65.40 EIV 237.80 Axial positioning of the rotor in the cylinder (the axial clearance measurement values of all thrust bearing position benchmarks are expressed in the X+ direction and X- direction) Actual measurement X+ 2.8 X- 1.7 2. Installation guide front end (rear end symmetry) Front/rear Front/rear Front bearing seat Rear bearing seat Front cylinder Rear cylinder 3. Front steam seal assembly clearance requirements Actual measurement SR1 0.20-0.40 0.30 SR2 0.20-0.40 0.30 SA1 1.8-2.2 2.30 SA2 2.55-2.95 2.70 4. Front cylinder cat claw screw assembly clearance requirements Actual measurement S Left 0.11-0.22 0.20 Right 0.16 S1 Left ≥ 1.6 3.20 Right 2.80 S2 Left ≥ 23.6 25.5 Right 25.5 S3 Left 1.1-1.3 1.2 Right 1.2 L Left 25.1 Right 25.2 5. Front outer cylinder guide assembly clearance requirements Actual measurement S 0.01-0.03 0.02 6. Actual measured assembly clearance requirements for front bearing seat guide parts S 0.01-0.03 0.01 7. Actual measured assembly clearance requirements for front bearing seat connecting parts S Front left 0.025-0.035 0.03 Right 0.035 Rear left 0.025-0.035 0.035 Right 0.03 S1 Front left ≥ 1.6 6.2 Right 5.6 Rear left 5.9 Right 5.7 S2 Front left ≥ 22.7 21.9 Right 22.3 Rear left 22.1 Right 22.1 8. Actual measurement requirements for front bearing seat seal ring S 1.5-2.0 1.8 S1 0.043-0.119 0.08 9. Actual measurement requirements for front journal assembly clearance S 0.188-0.238 0.20 D 125 124.82 10. Thermal expansion indication requirements Actual measurement S 0.3-0.5 0.40 11. The thrust bearing assembly clearance requirements Actual measurement SA1 0.33-0.43 0.33 SR1 0.05-0.12 0.08 12. The emergency interrupter assembly clearance requirements Actual measurement R+ 0.8-1.2 1.15 R- 0.8-1.2 0.85 S 0.8-1.0 0.90 13. Actual measured assembly clearance requirements for bearing seat tie rod bolts S left 0.09-0.12 0.10 S right 0.10 14. Actual measured assembly clearance requirements for rear bearing seat guides S 0.01-0.03 0.02 15. Actual measured assembly clearance requirements for rear steam seal SR1 0.20-0.40 0.40 SR2 0.20-0.40 0.40 SA1 3.1-3.9 3.2 SA2 4.6-5.4 5.2 16. Actual measurement clearance requirements for rear cylinder cat claw bolt assembly S Left 0.11-0.22 0.12 Right 0.13 S1 Left 1.1-1.3 1.3 Right 1.3 L Left 11.2 Right 11.9 Seventeen. Actual measurement requirements for assembly clearance of rear cylinder adjustment components S 0.02-0.041 0.03 Eighteen. Actual measurement requirements for rear bearing seat seal ring S 3.2-3.7 3.6 S1 0.043-0.143 0.10 Nineteen. Actual measurement requirements for assembly clearance of rear journal S 0.188-0.238 0.205 D 125 124.81 20. Actual measurement requirements for assembly clearance of eccentric bolts S 0.02-0.029 0.02 21. Actual measurement requirements for manual turning device S+ 5-6 5.4 S- 3-4 3.5 Gasket front 2.4 rear 2.4 22. Actual measurement requirements for assembly clearance of vertical adjustment components S1 0.02-0.06 0.05 S2 0.11-0.17 0.15 23. Actual measurement of internal steam seal assembly clearance requirements SR1 0.30-0.56 0.38 SR2 0.50-0.76 0.6 SA1 1.7-2.3 1.7 SA2 2.7-3.3 2.9 24. Actual measurement of assembly clearance requirements for horizontal adjustment components S 0.025-0.06 0.05 25. Steam chamber assembly gap required measured S 0.02-0.06 0.045 26. Angle ring assembly clearance 1 required measured S1 0.07-0.12 0.12 0.12 0.12 0.12 S2 2.4-3.1 2.4 2.4 2.4 2.4 S3 ≥3.1 4.2 4.1 4.1 4.1 27. Angle ring assembly clearance 2 requires actual measurement S1 ≥0.8 2.8 2.9 2.9 2.9 S2 ≥1.0 2.8 2.8 2.8 2.8 S3 ≥1.25 3.0 3.1 3.0 2.9 28. Guide vane holding ring flow gap level SRLE SRLA SALE SALA Requirements for actual measurement Requirements for actual measurement Requirements for actual measurement Requirements for actual measurement 2/102 0.6-0.87 0.60 5.9 6.25 3/103 0.3-0.56 0.40 0.30-0.56 0.40 2.7 3.75 3.7 4.2 4/104 0.3-0.56 0.40 0.30－0.56 0.40 2.8 3.9 3.8 4.3 5/105 0.3－0.56 0.40 0.30－0.56 0.40 2.8 3.9 3.9 4.35 6/106 0.3－0.56 0.40 0.30－0.56 0.40 2.9 4.1 4.1 4.5 7/107 0.3－0.56 0.40 0.30－0.56 0.40 2.9 4.0 4.2 4.6 8/108 0.3－0.56 0.40 0.30－0.56 0.40 3.0 4.0 4.3 7. Construction machinery and materials No. Name Specification Quantity 1 Kerosene 200Kg 2 Sodium hydrogen phosphate 200Kg 3 Sandpaper 100# 100 sheets 600# 200 sheets 4 Copper sheet δ＝0.05 10Kg δ＝0.10 5Kg δ＝0.15 5Kg δ＝0.50 5Kg 5 Rag 100Kg 6 Plastic cloth white and transparent 200Kg Colored 100m2 7 Lithium-based 3# grease 10Kg 8 Molybdenum disulfide 20Kg 9 PTFE sealing tape 30 rolls 10 Sealant 704 glue 40 boxes 11 Sealant 604 glue 20 boxes 12 Copper rod φ30 1m φ50 1m 13 4 plastic basins 14 Asbestos cloth 30m2 15 Flour 200Kg 16 White solid cloth 50m 11. Construction record form 11.1 Machine disassembly and assembly clearance record 11.2 Machine coupling alignment record 11.3 Machine and equipment single unit test run record (1), Machine and equipment unit test run record (2) 12. Appendix 1: Steam turbine overhaul content 9.1 includes intermediate repair content 9.2 Dismantle and install cosmetic panels and insulation layers 9.3 Check whether the cylinder has cracks, erosion, damage, and whether there are any defects such as leakage marks on the joint surface, deal with it if necessary, check the sliding pin system and cylinder level 9.4 Inspection, Clean the partition and nozzle, adjust the clearance between each part of the partition 9.5 Check, clean or replace some air seals and springs, adjust the air seal gap 9.6 Replace all "O" rings 9.7 Check the rotor radial and end face runout values, shaft straightness, check blades, shrouds, rivets, etc. Whether there are looseness, cracks, fractures, corrosion and other defects, make necessary adjustments according to the specific situation. 9.8 Inspect, clean the cylinder bolts and nuts, and conduct non-destructive testing, and replace them if necessary. 9.9 Perform inspections on the speed governor, extraction regulator, emergency safety device and power transmission mechanism. Inspect, calibrate or replace new parts 9.10 Disassemble and inspect or repair the main air valve, speed control valve and air extraction valve, check the straightness of each valve stem, straighten or replace new parts if necessary 9.11 Inspect, clean the turning device system 9.12 Inspect, clean the fuel tank, energy accumulator, etc.
Yes, but the information provided by Master ZHOUHUI is also very important