1. GAS TURBINE OPERATION AND MAINTENANCE
P2M FTUI
September 2008

2. Operating Factors Affecting Maintenance
Type and quality of fuel
Condensate, contaminants, etc
Starting Frequency
Thermal cycles
Load cycles
Environment
Abrasive and corrosive condition

3. Recommended Inspection Interval
Following table shows the operating hours at which inspection should be performed for operation on gas fuel and continuous duty
Recommended Inspection Interval
Note: (1) Hours mean Ëquivalent Operating Hours”reflecting the operation conditions of Gas Turbines

4. “Roll-in and Roll-out” Procedure
One (1) complete set of hot parts shall be ready for Rolling-in. The parts taken out (Roll-out) shall be reused/repaired/rejuvenated prior to the next inspection

5. Summary of GT Inspection
Procedure
Inspection Items
Combustor Inspection
Dismantling combustor basket
Visual inspection & NDT (1) of fuel nozzles, combustor baskets and transition pieces
Visual inspection of turbine blade row 4 and vane row 1 and 4
Visual inspection of compressor IGV, blade row 1 and vane row 1
Turbine Inspection
Lifting the upper housing of the turbine
Visual inspection and NDT (1) of turbine blades, vanes and seals
Combustor inspection is carried out at the same time
Major Overhaul Inspection
Lifting the upper housing of the turbine and compressor
Lifting the rotor
Visual inspection & NDT (2) of all components from expansion joint of the inlet air to the first expansion joint of the exhaust gas
Inspection of auxiliaries, control systems and instruments
NDT (1) : Non Destructive Test (Penetrant Test) NDT (2) : Non Destructive Test (Penetrant Test, Magnetic Particle test and Ultrasonic test

6. Combustor Inspection No 1. Compressor inlet (1)
No 2. Turbine blade row 4 (1)
No 3. Flame detector and igniter (2)
No 4. Fuel nozzle (2)
No 5. Combustor basket (2)
No 6. Transition piece (2)
(1): Visual Inspection
(2): Roll-in & Roll-out Parts

7. Combustion Inspection Schedule (for one (1) Gas Turbine)

8. Turbine Inspection No 6. Turbine blade (2) No 1. Compressor inlet (1)
No 7. Turbine vane (2)
No 8. Compressor last row and OGV’s blade and diaphragm (1)
No 1. Compressor inlet (1)
No 2. Flame detector and igniter (2)
No 3. Fuel nozzle (2)
No 4. Combustor basket (2)
No 5. Transition piece (2)
(1): Visual Inspection
(2): Roll-in & Roll-out Parts

9. Turbine Inspection Schedule (for one (1) Gas Turbine)

10. Major Overhaul Inspection
No 1. Flame detector and igniter (1)
No 2. Fuel nozzle (1)
No 3. Combustor basket (1)
No 4. Transition piece (1)
No 5. Turbine blade (1)
No 6. Turbine vane (1)
No 7. Compressor blade and diaphragm
No 8. Exhaust turbine and compressor casing
No 9. Compressor blade ring
No 10. Turbine blade ring #1, #2, #3 and #4
Turbine journal brg and thrust brg
Rotor (2)
(1): Visual Inspection
(2): Roll-in & Roll-out Parts

11. Major Overhaul Inspection Schedule (for one (1) Gas Turbine)

12. Routine Maintenance

13. Hot Parts Expected Life Time
The expected life of hot parts has been established based on design strength and the result of past operating experiences. The expected hot parts life hours with qualified repairs are as follows:

14. Definition of “EOH” Equivalent Operating Hours
To calculate hours of operation equivalent to base load continuous duty operation, when operation has been with liquid fuel and/or cyclic duty, it is necessary to segregate the actual hours of operation by duty (fired hours per start) and fuel (gas or oil). These segregated values are then used in the following equation to calculate the hours equivalent to operation at base load with gas fuel.
where,
H = equivalent continuous duty gas fired hours
BHG = base load operating hours with gas fuel
BHO = base load operating hours with distillate oil fuel
PHG = peak load operating hours with gas fuel
PHO = peak load operating hours with distillate oil fuel
CDF = cyclic duty factor, determined from the following table

15. Cyclic Duty Factor Table

16. Hot Parts Life Evaluation
Deterioration
Creep under High Temperature
Low Cycle Fatigue
Metal Loss by Surface Oxidation & Corrosion
Life diagnosis
Load Cycles
Start / Stop Frequency
Fuel Quality
Environment
Maintenance Practice
Life diagnosis procedure is decided based on each customer’s operational conditions

17. Life Evaluation Method
Evaluation for Maximum Use-up
Turbine Blade
Metallurgical Analysis
γ’ phase
Creep Rupture Property
Turbine Vane
Precipitated Carbide
Tensile Property

18. Life Evaluation Process for Turbine Blade

19. Life Evaluation Process for Turbine Vane

20. Life Extension Technology
Reheat Technology
High temp. heating of deteriorated super alloy
Decomposition & re-solution of hypertrophied γ’ phase and intergranular carbide
Standard heat treatment the material
Recovery of mechanical properties

21. Terima Kasih