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Gas turbine
The document discusses gas turbines used at an NFL power plant in Vijaipur. It provides details on the models, ratings, and loads of three gas turbine generators (GTGs). It then discusses heavy duty gas turbines from GE in terms of their configurations, frame sizes, speeds, and applications. The rest of the document goes into extensive technical details about the components, workings, inspections, and factors that influence gas turbines, including compressors, combustion systems, turbines, bearings, and more.
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Gas turbine
- 1. GAS TURBINES Presented by. . . Prem Baboo
- 2. GAS TURBINES ATN.F.L. VIJAIPUR GTG-1 & 2: PG-5361 P RATING at 45OC on NG & Naphtha Base / Peak Load: 17225 / 19237 KW & 16990 / 18980 KW GTG-3 : PG-5371 PA RATING at 35OC on NG & Naphtha: Base / Peak Load: 19970 / 21910 KW & 19740 / 20950 KW GT(PAC) : M-5261 RA
- 3. HEAY DUTY GASTURBINES MS5000 SINGLE and TWO shaft configurations for both Generator drive and Mechanical drive. MS5001 and MS6001 are Gear-Box driven units that can be applied in 50 Hz and 60 Hz. Beyond Frame 6 all are direct drive units. MS7000 series for 60 Hz >>>3600 RPM. MS9000 series for 50 Hz >>>3000 RPM.
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- 5. Generator Applications 35,800 ~345,600 HP (26,000 ~ 255,600 kW)
- 6. Mechanical Drives 14,520 ~108,990HP (10,828 ~ 80,685 kW)
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- 11. Compressor Draws in air& compresses it Combustion Chamber Fuel pumped in and ignited to burn with compressed air Turbine Hot gases converted to work Can drive compressor & external load
- 12. Compressor Draws in air& compresses it Combustion Chamber Fuel pumped in and ignited to burn with compressed air Turbine Hot gases converted to work Can drive compressor & external load
- 13. Compressor Draws in air& compresses it Combustion Chamber Fuel pumped in and ignited to burn with compressed air Turbine Hot gases converted to work Drive compressor & external load
- 14. Theoretical and ActualBrayton Cycle
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- 18. Factors Affecting GasTurbine Performance Since the gas turbine is an air-breathing engine, its performance is changed by anything that affects the density and / or mass flow of the air intake to the compressor Ambient Air Temperature Site Elevation / Atmospheric Pressure Humidity Inlet and Exhaust Losses Fuels Turbine Cooling ( . . . air extraction )
- 19. EFFECT OF AMBIENTTEMPERATURE CURVES ARE DIFFERENT FOR DIFFERENT MODELS AND CYCLE
- 20. EFFECT OF ATMOSPHERICPRESSURE AIR FLOW & OUTPUT DECREASES ::::::: AS SITE ELEVATION INCREASES
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- 22. EFFECT OF INLET &EXHAUST LOSSES
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- 28. METHOD TO IMPROVETHE EFFICIENCY
- 29. GAS TURBINE MANILYCAN BE DIVIDED IN TO 4 SUB-SECTION ACCSSORY COMPARTMENT MAIN GAS TURBINE LOAD GEAR COMPARTMANT GENERATOR AND EXCITER
- 30. MAJOR COMPONENTS OF GASTURBINE INLET SYSTEM COMPRESSOR COMBUSTION SYSTEM TURBINE EXHAUST BEARINGS
- 31. INLET SECTION Consists ofinlet plenum which inducts air into the compressor inlet casing
- 32. COMPRESSOR SECTION COMPRESSOR SECTIONCONSISTS OF Inlet Casing Forward Casing Aft Casing Discharge Casing Blading Compressor Rotor
- 33. INLET CASING The inletsection directs the flow of outside air from the air inlet equipment into the compressor blading. Contains the inlet guide vane assembly. The No #1 Bearing assembly and the low pressure air seals.
- 34. INLET GUIDE VANE IGVpermits fast, smooth acceleration of the turbine without compressor surge. A hydraulic cylinder mounted on a base cross member actuates the IGV through a large ring gear and multiple small pinion gears.
- 35. FORWARD CASING It containsstator blading for stages 0 through 3. Bleed air from the fourth rotor stage can be extracted through four ports which are located about the aft section of the compressor casing.
- 36. AFT CASING It containsthe stator blading for stages 4 through 9. Bleed air from 10th rotor stage (between 9th and 10th stator stages) can be extracted through four ports.
- 37. DISCHARGE CASING It containsstator blading for stages 10 through 16 and Exit guide vane stages 1 and 2. Provides the mounting surface for the combustion chambers. Supports the inner case assembly.
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- 43. COMBUSTION SECTION THE COMBUSTIONSYSTEM CONSISTS OF Ten Combustion Chambers. Fuel Nozzles. Cross fired tubes. Transition pieces. Combustion Liners. Spark plugs and Flame detectors.
- 44. GAS TURBINE COMBUSTIONSYSTEM
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- 46. FUEL NOZZLE Dual fuel Gasand HSD Liquid fuel atomization is with air Purge air provision for liquid path
- 47. CROSS FIRE TUBES Carriesflame from Chambers No #1 & # 2 to all other chambers during start up and to unfired Combustion Chambers
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- 49. Spring Seal Body Cross fire tube collar CoolingHoles SUBLEVEL COMPONENTS Cap Assembly Fuel Nozzle Collar Liner Stopper
- 50. Fuel Nozzles Combustion Components Rotor Nozzles Buckets OVER VIEWOF GAS TURBINE TP Location
- 51. FWD Frame FWD Mount TP body AFT Mount Float seals SubLevel Components . . .
- 52. TURBINE SECTION II ndSTAGE NOZZLE I st STAGE BUCKETS I st STAGE NOZZLE TRANSTION PIECE
- 53. Power nozzles providethe mechanism of converting energy of burned gases into kinetic energy that drives the turbine. The power nozzles are located at turbine Section of the unit. Hot combustion gases hit the nozzle to accelerate and change direction. NOZZLE
- 54. GAS TURBINE NOZZLE FIRSTSTAGE NOZZLE SECOND STAGE NOZZLE
- 55. Support ring Stg 1Bucket Stg 2 Diaphragm Stg 2 Nozzle Stg 2 Bucket Stg 1 Shroud Stg 2 Shroud
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- 58. EXHAUST CASING Exhaustcasing directs exhaust gases to Exhaust Duct Contains Bearing No # 2 assembly Acts as a Diffuser to push exhaust gases into Exhaust Duct
- 59. BEARINGS Gas turbine issupported on two nos elliptical journal bearings Bearing 1 at compressor inlet casing Bearing 2 at exhaust casing end Bearing 1 also consists of active and non active thrust bearings
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- 61. ACCESSROY COMPARTMENT STARTINGDEVICE ( DIESEL ENGINE) TORQUE CONVERTER HYDRAULIC RATCHET MECHANISUM JAW CLUTCH AUXILLARY LUBE OIL AND EM LUBE OIL PUMP AUXILLARY HYDRAULIC OIL PUMP LUBE OIL TANK FLOW DIVIDER HIGH PRESSURE LIQUID FUEL FILTER ACCESSORY GEAR BOX
- 62. ACCESSORY GEAR BOX PROVIDES DRIVE TO MOST OF THE SUPPORTS SYSTEM REQUIRED FOR CONTROL AND PROPER FUNCTIONOING OF GAS TURBINE LIKE MAIN LUBE OIL PUMP MAIN HYDRAULIC OIL PUMP ATOMISING AIR COMPRESSOR LIQUID FUEL FORWARDING PUMP MECHANICAL OVERSPEED TRIP MECHANISUM
- 63. CUT VIEW OFACCESSORY GEAR BOX
- 64. OTHER SUPPORT SYSTEM COOLINGWATER SYSTEM FIRE PROTECTION SEALING AND COOLING AIR SYSTEM
- 65. COOLING AND SEALINGAIR PARTS OF THE TURBINE WHICH ARE COOLED BY AIR ARE : The first and second stage turbine wheel forward and aft faces. First and Second stage Nozzles. Turbine shell and support struts. Combustion liners. Transition pieces. Pressurising the bearing oil seals.
- 66. COOLING AND SEALINGAIR CIRCUIT
- 68. 4th STAGE EXTRACTION Thisair cools the shell surrounding the first and second stage nozzle , First stage nozzle and turbine wheels. Also cools the support struts which are in hot gas stream of exhaust frame.
- 69. 10th STAGE EXTRACTION Airis fed through the second stage nozzle partition for cooling the aft surface of the first stage turbine wheel and forward surface of the second stage turbine wheel. Seal air for bearing #1 and #2. To avoid pulsation / surging during start up / shutdown
- 70. SURGING Compressor Inlet VolumeFlow is proportional to Speed Q ~ N Compressor Power is proportional to third Power of Speed P ~ N3 Total Pressure Ratio is proportional to Speed squared P2 / P1 ~ N2 Fan Laws
- 71. The Reason forusing 10th stage Bleed on this type of Axial Compressor, can be made more clear when we look at Compressor running at 100% and 50% of speed At 100% Speed IN OUT V1 = 100 m3/sec V2 = ??? P1 = 1 bar P2 = 11.5 bar k = 1.4 Poisson’s Law: P1 x V1 k = P2 x V2 k 1 x 100 1.4 = 11.5 x V2 1.4 V2 = 17.5 m3 / sec At 50% Speed IN OUT V1 = 50 m3/sec V2 = ?? P1 = 1 bar P2 = 11.5 =2.875 bara k = 1.4 4.0 Poisson’s Law: P1 x V1 k = P2 x V2 k 1 x 50 1.4 = 2.875 x V2 1.4 V2 = 23.52 m3 / sec
- 72. Compressor Characteristics with IGVand 10th Stage Bleed
- 73. COMPRESSOR 17th STAGEAIR Channelled internally to the forward surface of the first stage turbine wheel. This air flow provides a source of cooling air for the first stage wheel and is exited into the exhaust stream.
- 75. SHROUDS Shrouds primaryfunction is to provide a cylindrical surface for minimising buckets tip clearances. To provide high thermal resistance between hot gases and the comparatively cool shell. By accomplishing this the shell cooling load is drastically reduced and shell diameter is controlled. Shell roundness is maintained, and the important turbine Clearance are assured. FIRST STAGE SHROUDS SECOND STAGE SHROUDS
- 76. Spring Seal Damage Body Damage XFTCollar Damage Stopper Damage Fuel Nozzle Collar Damage TBC Damage Ovality POSSIBLE DEFECTS IN COMBUSTION LINERS Cowl Cap Damage
- 77. AFT End bracket damage Creep deflection AFTEnd body damage Seal damages TP Body damage Spring seal mark damage in inner body Inner / Outer Slot damage TBC Coating damage Side Slot damage Possible defects in Transition Pieces
- 78. COMPRESSOR ROTOR BLADEFAILURE
- 80. Typical Damage Corrosionon leading edge, trailing edge and both side walls. Oxidation Erosion on the partitions and pressure side walls. Cracks at both pressure and suction side of the segment as well as both side walls.
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- 82. To ensure Unitavailability at full potential performance & to avoid unforeseen failures, taking in to consideration of the operational limiting factors, GE has recommended specified inspection intervals (GER 3620G). Combustion Inspection HGP Inspection Major Inspection. INSPECTION
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- 89. COMBUSTION INSPECTION FUEL NOZZLES CROSSFIRE TUBES COMBUSTION LINERS TRANSITION PIECES CHECK VALVES SERVICING BORESCOPIC INPSECTION OF TURBINE SECTION
- 90. HOT GAS PATHINSPECTION COMBUSTION INSPECTION SCOPE + ALL STAGES NOZZLES AND BUCKETS SHROUDS TARNSITION PIECES NOZZLE DIAPHRAGMS WHEEL SPACE SEALS 6 POINT CHECK OF COMP. ROTOR
- 91. MAJOR INSPECTION HGPI ,CI SCOPE + COMPRESSOR ROTOR AND STATOR BLADE ALL BEARINGS LOAD GEAR BOX ACCESSORY GEAR BOX INELT / EXHAUST SYSTEM
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- 93. MAJOR FACTORS INFLUENCING MAINTENANCEAND EQUIPMENT LIFE FUEL FIRING TEMPERATURE CYCLIC EFFECTS STEAM / WATER INJECTION Maintenance COST & Equipment LIFE are influenced by key SERVICE FACTORS
- 94. • Fuel Liquidfuel has high bulk density and releases high radiant thermal energy. This would over heat the parts resulting in early thermal fatigue failure. Liquid Fuel contains impurities (Na, K, Va) which would accelerate Hot Corrosion besides erosion. One hour of liquid fuel operation is equivalent to 1.5 hours of Gas operation at base load.0 1 2 3 4 7 9 11 13 15 20 Fuel Percent Hydrogen by Weight in Fuel IntervalReductionFactor Residual Distillates Heavy Light Natural Gas
- 95. Permissible Maximum concentration ofcontaminants Fuel, Air and Steam / Water (Na + K ) < 1 PPM Pb < 1 PPM V < 0.5 PPM Na & K can be desalted, but V cannot be removed Mg added to counter it in Ratio Mg : V :: ( < 3.1 : 1) Heavier Hydrocarbon Fuel Release higher Radiant Thermal Energy Contains corrosive elements Na, K, V and Pb Accelerates Hot Corrosion SPECIFICATION of Fuel Specific Gravity < 0.96% Water content < 1.00%
- 96. • Firing TemperatureHigher Firing Temperature (Peak Load) releases higher thermal energy resulting in distortions & Creeping of components. One hour of peak load operation is approximately equivalent to 6 hours of Base load operation.
- 97. INCREASING 56o C FIRING TEMPERATURE OUTPUT increases 8 ~ 13 % SIMPLE CYCLE EFFICIENCY increases by 2 ~ 4 %
- 98. • Cyclic effectsNormal cyclic operation of start, operation & shutdown itself can cause cyclic stress, the severity is phenomenal in the case of emergency start & trips. This would result in cracks more so in combustion parts. One emergency trip cycle is approximately equivalent to 8 normal shutdown cycles.
- 99. CYCLIC EFFECTS Temperatureresponds quickly on edges Results in Thermal stresses Compressive strain during start-up acceleration and also at Full load Tensile strain during shut down
- 101. Steam / WaterInjection Steam or Water Injection used for control of emission or augmented power causes higher dynamic pressure and higher transfer of heat to Bucket & Nozzle resulting in higher metal temperature of these components.
- 102. STEAM / WATERINJECTION PURPOSE For emissions control Power augmentation CHANGES HEAT TRANSFER PROPERTIES Higher Gas Conductivity . . . Higher Heat Transfer . . Higher Metal Temp . . . . . . Reduced Part Life
- 104. PURPOSE OF COATINGSON GT COMPONENETS • Protection against erosion and hot corrosion. • Enhance the surface properties of base material. • Provide an Insulating Layer that reduces the underlying base material temperature.
- 105. COATINGS ON GASTURBINE COMPONENTS . . . COMPRESSOR COMPONENTS COMBUSTION COMPONENTS HOT GAS PATH COMPONENTS GECC -1 Coating – GE Cold Coating on Blades for Corrosion Resistance
- 106. AISI 403 STAINLESS SACRIFICIAL UNDERCOAT CERAMIC TOP COAT TwoLayer System Base Coat:Aluminum Filled Base Material ForOxidation Protection TopCoat :Ceramic ForCorrosion Resistant GECC1 ROTOR COATING . . . }3 Mils thick
- 107. Benefits Extend ComponentLife Longer LastingCompressor Efficiency Fouling hasless tendency tostick Easier to remove fouling Protect parts from Environment during prolonged periods of Inactivity GECC1 ROTOR COATING . . .
- 108. GECC1coatingon Rotor • Assembledrotors •Un-stackedrotors Blade &Wheels StatorBlades IGVs GECC1 ROTOR COATING . . .
- 109. COATINGS ON GASTURBINE COMPONENTS . . . COMPRESSOR COMPONENTS COMBUSTION COMPONENTS HOT GAS PATH COMPONENTS TBC COATING ID of Combustion Liners AND Transition Pieces HARD FACE COATING Mating surfaces of : X fire tube & X fire tube collar Fuel Nozzle & Nozzle collar Fuel Nozzle Tip, Bull Horns
- 110. “NiCrAlY Coatings” followed byCERAMIC (Zirconia, ZrO2) MCrAlY increase the adherence of the oxide layer to the substrate (base Ni alloy) COMPOSITION MCrAlY (M = metal) based bond coating 18% Chromium, 22% Cobalt, 12% Aluminum and 0.5% Yttrium Temperatures in Gas Turbine around 1350° Melting point of these Nickel alloys is about (1200~1315°C)!
- 112. COATINGS ON GASTURBINE COMPONENTS . . . COMPRESSOR COMPONENTS COMBUSTION COMPONENTS HOT GAS PATH COMPONENTS • Diffusion Coating Pt-Al (up-to 1983) ( Electroplating of --- ……….Platinum 0.006 mm > Al by Diffusion Packing ) • PLASMAGUARD GT-29 / GT-29 PLUS / GT-29 IN-PLUS • GT-33 IN-COAT™ and GT-33 IN-PLUS™ •PLASMA GUARD GT-43 / GT-20 (low temperature) for SHROUDS
- 114. Coatings on Shrouds…… see the difference with uncoated shrouds HOT GAS PATH COMPONENTS . . .
- 115. MATERIAL OF CONSTRUCTION Combustion Liner Transition Piece 1st Stage Nozzle 1st Stage Bucket 2nd Stage Nozzle 2nd Stage Bucket IGV’s Compressor Rotor Blades Compressor Stator Blades RA-333 Hastelloy-X Hastelloy-X Nickle-base super alloy o FSX-414 Cobalt-base super alloy GTD-111/GT-29+Coating Nickle-base super alloy N-155 Iron-base super alloy U-500 Nickle-base S-Alloy GTD-450 Precipitate Hardened Martensitic Steel o GTD-450 / AISI-403 o AISI-403
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