Siement Turbine Over Hauling Procedure

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Text of Siement Turbine Over Hauling Procedure

S.Rameshkumar

Mechanical Maintenance

Siemens, Wesel, Germany NG90/81/45-4IZ +WK80/90/0-3RHP Turb+SA21LP TurbPage 1 of 75

TURBINE OVERHAULINGScope of Work

INDEX1.0 Work Related Documents :1.1 1.2 List of drawings. Turbine Service Manual Siemens Ref : ESO/0689/86-05-13/KWU/la-mg.

2.0 3.0

Preparation for Inspection. Alignment Checks :3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 Open Bearing pedestal. Uncouple main oil pump. Uncouple Generator. Uncouple LP rotor. Check alignment between the Main Oil Pump and the HP Turbine. Check alignment between the HP Turbine and the LP Turbine. Check alignment between the Generator and the LP Turbine. Check internal alignment of the LP Turbine. Check internal alignment of the HP Turbine.

4.0

Disassembly :4.1 4.2 4.3 4.4 HP Turbine. LP Turbine. Valve blocks. Lube oil system.

5.0 6.0

Non-Destructive Testing. Fact-Finding :6.1 6.2 6.3 6.4 Components, Parts and Individual areas to be inspected. Component / Part findings checklist. List of Fact-Finding Tools, instruments and accessories. List of potential findings.

7.0

Reassembly :7.1 7.2 7.3 7.4 7.5 LP Turbine. HP Turbine. Valve blocks. Alignment checks. Lube oil system.

8.0

Commissioning :

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Turbine Overhauling - Scope of Work

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2.0 PREPARATIONS FOR INSPECTION :

Evaluate latest operating records and related data. Check for availability of spare parts. Perform functional inspection of modular units. Perform leak checks in the form of visual and tactile inspections. Check shaft-line grounding. Check turbine-generator running behavior prior to shutdown; perform vibration measurements. Set up jobsite; ready all scaffolding, tools etc. Measure vacuum reduction rate. Shutdown the system. Cool turbine-generator via turning gear operation. Disconnect oil pumps, with the exception of the lift-oil pump. Remove turbine enclosure. Remove insulation. Remove vibration pickups. Protect ends of cables against damage.

General Recommendations :

Use only Silicon-free lubricants on the oil side. Observe all relevant accident prevention regulations. Observe all relevant fire prevention regulations. Exercise caution in the handling of cleaning agents and acids (Wear protective clothing). Observe manufacturers parts identification system at each step of assembly/disassembly. The following sealants are recommended : For the steam side : Led plate, Birkosit. For the oil side : Hylomar. The followings lubricant is recommended : Gleitmo 160

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3.0 ALIGNMENT CHECKS : 3.1 Open Bearing Pedestal :Procedure :

Record pedestal position indicator readings on the HP Turbine (Z 37, Z 38; View VI, Section U1U1) and LP Turbine (Z 58, Z 60; Detail V4).

Record rotor position indicator readings on the LP turbine (Z 72; Part 3). Remove top of rear bearing pedestal (Z 22) Remove seal rings from the top and bottom halves of the bearing pedestal. Remove center top-half bearing pedestal (Z 15). Remove seal rings from the top and bottom halves of the bearing pedestal. Dismantle and store piping from the front top-half bearing pedestal. Remove front top-half bearing pedestal (Z 1). Remove seal rings from the top and bottom halves of the bearing pedestal. Remove top-half thrust bearing (Z 3). Remove thermocouples (Z 7) from the top and bottom halves. Check and record the rotor position in the bottom-half thrust bearing. Measure and record the alignment dimensions of the HP and LP turbines (cf. assembly data sheet). Remove bottom-half thrust bearing. Measure and record axial movement of the shaft line (cf. assembly data sheet). Reassemble bottom-half thrust bearing

3.2 Uncoupling Main Oil Pump :Procedure :

Remove hall generators (Z 14) Remove enclosure (Z 10; part 60, 65) Check identification markings on the coupling parts (part 100) Remove centerpiece of sleeve. Remove circlip Pull both sleeve sections off of the hubs.

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Evaluation :

Teeth. Clean couplings parts, protect against corrosion and store.

3.3 Uncoupling Generator :Procedure :

Check identification markings on the coupling flanges, bolts and nuts (Z 72.1) remove coupling nuts. Remove coupling bolts. Clean coupling nuts and bolts, protect against corrosion, and store. Turn jack screws in up to contact face. Continue turning the jack screws to push apart the coupling flange. Push the generator rotor up to stop in the positive direction.

3.4 Uncoupling L. P. rotor :Procedure :

Position the lifting fixture (Z 21) Provide metal strips for the support bearing. Check the identification markings on the coupling flange, bolts and nuts (Z 72). Remove coupling nuts. Turn jack screws in up to the contact face. Continue turning jack screws to press the two halves of the coupling flange apart by 3mm. Hand-tighten the coupling nuts.

3.5 Check Alignment between the Main Oil Pump and the HP TurbineProcedure :

Attach measuring instrument. Check and record the alignment between the pump shaft and the turbine rotor.

3.6 Check alignment between the HP Turbine and the LP Turbine Procedure :

Attach measuring instrument. Check and record the alignment between the HP rotor and the LP rotor.

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3.7 Check alignment between the Generator and the LP Turbine Procedure :

Attach measuring instrument. Check and record the alignment between the LP rotor and the Generator.

3.8 Check internal alignment of the LP Turbine Procedure :

Measure and record the exact values at the rear bearing pedestal measuring points (Z 22). Measure and record the exact values at the outer-casing circumferential profile measuring points. Check for full contact between the pedestal support brackets and the base plate (Z 85, 59, 60; Sections F2-F2, F4-F4).

Remove coupling nuts (Z 72). Remove coupling bolts. Clean coupling nuts and bolts, protect against corrosion, and store. Use lifting fixture to support weight of rotor (Z 21). Press coupling flange apart by turning in the jack screws. Push rotor in the positive direction up to 1.0mm ahead of the stop. Install support bearing, take load off of and remove the lifting fixture. Mount rear top-half bearing pedestal.

3.9 Check internal alignment of HP Turbine Procedure :

Measure and record dimension L (assembly data sheet) on the front support bracket seats. Measure and record the exact values at the front and center bearing pedestal measuring points (Z 71, 1, 15).

Measure and record the exact values at the outer-casing circumferential profile measuring points. Check for full contact between the rear support brackets and the base plate (Z 37, 39; Section P3P3).

Mount the center and front top-half bearing pedestals. Disconnect the lift-oil pumps.

4.0 DISASSEMBLY :

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4.1 HP Turbine

Open Outer Casing

Procedure :

Disconnect flange joints of upper steam inlet pipes; support weight of pipes as necessary. Dismantle the upper cross-around piping, incl. swing disk valves; plug openings, store piping, protect valves against corrosion and store.

Remove and store wall temperature sensor (Z 36) Ream out (clean) taper-pin bores (Z 26, Part 14) Bring shoulder bolts into contact with the auxiliary support brackets (Z 38, Section P1-P1, Part 30).

Remove spacer bolts, washers and disk springs from the front support bracket seat (Z 38, Section P1-P1, Parts 39-43).

Insert one each additional washer between the spacer bolts and existing washers, and retighten the spacer bolts.

Loosen joints bolts as per specification. Clean and screw in guide bolts. Clean jack screws; apply lubricant to the threads; screw in. Hitch up the top-half outer casing horizontally onto the proper lifting bosses. Turn in the jack screws to uniformly lift the top half outer casing by approx. 30 mm. Lift off top-half outer casing.

Evaluation :

Joint faces, guides, support brackets seat, spherical washers, L-rings. Protect top-half outer casing against corrosion and store. Protect spherical washers, spacer bolts, washers and disk springs (Z 38; Section P1-P1, Parts 3943) against corrosion and store.

Remove upper spherical washers from the stationary blading carrier (Z 45; Section K1-K3, Part 7) and inner seal ring (Z 37; Section K-K, Part 287); protect against corrosion and store.

Remove joint bolts from the bottom-half outer casing.

Open Stationary Blade Carrier

Procedure :

Sequence items 500, 525, 550 (Z 42).

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Remove spot welds from the joint bolt nuts. Ream out (clean) taper-pin bores. Clean jack screws, apply lubricant to threads; screw in Hitch up top-half stationary blade carrier, thereby maintaining a horizontal position. Turn in jack screws to lift top-half by about 30mm. Lift off stationary blade carrier.

Evaluation :

Joint face, blades, seal strips, spherical washers. Protect top-half stationary blade carrier against corrosion and store.

Open Inner Casing

Procedure :

Remove and store pressure-instrument lines (Z 40, Part 391). Remove spot welds from the joint nut bolts. Ream out (clean) taper-pin bore