Power plant-basics

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Power plant-basics

  1. 1. POWER GENERATION PROCESS BASICS
  2. 2. BOILER / STEAM TURBO-GENERATOR UTILITY PLANT 40% Steam Condenser 20% Stack Lake Steam 6% Aux. Power + Losses 34% Electricity100%FuelAir Boiler Steam Turbine Generator Transmission THERMAL EFFICIENCY - 34%
  3. 3. BOILER / STEAM TURBINE-GENERATOR INDUSTRIAL CO-GENERATION Process Steam 65% 15% Process Plant Stack Steam 5% Aux. Power + Losses 15% ElectricityFuel100% Air Boiler Steam Turbine Generator Transmission THERMAL EFFICIENCY - 80%
  4. 4. SIMPLE CYCLE COMBUSTION (GAS) TURBINE 57-62% 100% Fuel Stack Combuster 3% Aux Power + Losses 35-40% ElectricityAir Compressor Turbine Generator Transmission THERMAL EFFICIENCY - 35-40%
  5. 5. GAS TURBINE INDUSTRIAL CO-GENERATION PLANT 20% Stack Stack Supplementary/ Auxiliary Fuel (Optional) Process Steam Process Plant 100% Fuel Combuster Exhaust GasAir Compressor Turbine Generator Transmission
  6. 6. GAS TURBINE 28% COMBINED CYCLE POWER PLANT Steam Condenser 20% Stack Stack Steam Lake Supplementary Fuel (Optional) 100% Fuel Steam Turbine Generator Transmission Combuster Exhaust Gas 12-15% ElectricityAir 6% Aux. Power + Losses 35-40% Electricity Compressor Turbine Generator Transmission Thermal Efficiency - 45-55%
  7. 7. UTILITY PLANT - FUNCTIONAL BLOCK DIAGRAM Switch Yard System Ash Handling System Station Electrical System Boiler Steam & Water System Air & Flue Gas System BOILER Fuel Preparation System Fuel Firing System Boiler Miscellaneous Systems Boiler Feed Pumps & UNIT#2 Deaerator System Turbine Steam System TURBINE- HP & LP Heaters System GENERATOR Turbine Supervisory & Control System Generator & Electrical System Turbine Miscellaneous Systems Turbine Bypass System Fuel Handling System DM Plant Station Miscellaneous Systems
  8. 8. CAPTIVE POWER PLANT - FUNCTIONAL BLOCK DIAGRAM Switch Yard System Ash Handling System Station Electrical System Steam & Water Air & Flue GasBOILER Fuel Preparation Fuel Firing Steam UNIT#2 UNIT#3TG HP & LP Heaters Supervisory & Control Generator & Electrical Miscellaneous Systems BFP’s & Deaerator System Fuel Handling System DM Plant Station Miscellaneous Systems
  9. 9. BOILER FUNDAMENTALS
  10. 10. BASIC DIAGRAM OF A BOILER SteamWater Steam / Water System BlowdownFuel Flue Gas Mixing of Heat Transfer Fuel & Air Surface FurnaceAir Ash
  11. 11. SALIENT FEATURES OF MODERN INDUSTRIAL& UTILITY BOILER• STEAM BOILER• WATER TUBE• SUPERHEATED STEAM• HIGH PRESSURE• WATER COOLED FURNACE• WATER CIRCULATION
  12. 12. COMBUSTION REQUIREMENTS Sufficient Combustion Air TemperatureFuel Combustion Mixing within aboveis Time Flammable IgnitionGasified Temperature Range Point Turbulence 3 T’s of Combustion
  13. 13. BASIC COMBUSTION CHEMISTRY Complete Heat(Air) Oxygen Fuel Flue Gas Products H2 H2O O2 + C CO2 Incomplete Heat Oxygen Fuel Flue Gas Products H2 H2O O2 + C CO2 CO H2 C • Other Combustibles - Sulphur to Sulphur Oxides • Non-combustible - Nitrogen to Nitrogen+Nitrous Oxides • Ash
  14. 14. BOILER WATER & STEAM SYSTEM Hot Reheat Steam Spray Water Main Steam Drum Attemperator Attemperator Cold Final Primary Final Reheat Platen Primary Re Re Super Steam Super Super Heater Heater Heater Spray Heater Heater WaterDownComers Flue Gas Economiser Feed Water Furnace Flue Gas Water Wall Out to Risers Air Heater Bottom Ring Header Simplified Process Diagram
  15. 15. BOILER WATER & STEAM SYSTEMProcess Performance Highlights• Heat Transfer by Radiation and Convection• Boiler Water Circulation - Natural or Controlled• Heat Transfer depends on Heat Transfer Area & Time• Heat Transfer is affected by Fouling, Boiler Pressure, Boiler Water Quality and % MCR Load
  16. 16. BOILER WATER & STEAM SYSTEMMajor Equipment• Economiser - Pre-heats Boiler Feed water• Boiler Drum - Separates water from steam and reduce solids in steam• Water Walls - Absorb heat from flue gas to evaporate boiler water• Superheaters - Heat up steam coming from boiler drum• Reheaters - Heat up steam coming from High Pressure turbine• Attemperators - Reduce superheat from steam
  17. 17. BOILER WATER & STEAM SYSTEMProcess Regulation• Drum Level - Regulation of Feed Water flow• Drum Water Quality - Blow down / Chemical Dozing• Fouling of Heat Transfer Surfaces - Blowdown / Soot Blowing• Main Steam Temperature - Attemperation / Burner Tilt• Hot Reheat Steam Temperature - Burner Tilt / Attemperation• Main Steam Pressure - Regulation of Combustion
  18. 18. AIR & FLUE GAS SYSTEMTo Air Cooled PA FAN A To Hot To ColdGuns PA Header PA Header From Scanner Air Fans FD Fans PA FAN B WINDOX A AH A ESP A P F L R E T I T ID Fan A FURNACE H C N N S Chimney O S S H H H ID Fan B ESP B AH B WINDBOX B FD FAN A FD FAN B Simplified Process Diagram
  19. 19. AIR & FLUE GAS SYSTEMProcess Performance Highlights• Generation of Draft - Natural / Induced / Forced / Balanced• Supply of Air for Transport of Pulverised Coal• Pre-heating of Air• Distribution of Air in Combustion Chamber• Recirculation of Gas• Fan capacity depends on Flow, Density & System Resistance• Fan performance is affected by temperature, density, barometric pressure and speed• Flue Gas Cleaning• Gas flow is restricted by ash deposits on boiler surfaces
  20. 20. AIR & FLUE GAS SYSTEMMajor Equipment• Air Path - Forced Draft Fans, Steam Coil Air Pre-heater, Regenerative Air Pre-heater & Wind-box• Gas Path - Induced Draft Fans and Stack• Gas Recirculation - Gas Recirculating Fans• Flue Gas Cleaning - Mechanical Precipitator, Electrostatic Precipitator and Gas Scrubber• Dampers
  21. 21. AIR & FLUE GAS SYSTEMProcess Regulation• Furnace Draft - ID Fan Inlet Vane Control and/or Variable Speed• Secondary Air Flow - FD Fan Variable Pitch Control• PA Header Pressure - PA Fan Inlet Vane Control• RAPH Cold End Temperature - SCAPH Control• Gas Recirculation - Damper Control
  22. 22. FUEL PREPARATION SYSTEM - COAL Raw Coal Bunker To Mill Discharge Valves To Hot PA Other Coal Feeder MillsCoal+Airto Burners Mill A Cold PA To Other Mills To Other Mills Seal Air Fans Simplified Process Diagram
  23. 23. FUEL PREPARATION SYSTEM - GAS/OILFuel GasSupply To Burners FCV FGTV PRV’s FUEL GAS Atomising Steam/Air PCV Fuel Oil Return Short Long Recirc Recirc PCV Fuel Oil Oil Heater To Burners Supply FCV FOTV Steam Fuel Oil Pumps FUEL OIL Simplified Process Diagram
  24. 24. FUEL PREPARATION SYSTEMProcess Performance Highlights• Coal Pulverizing - Direct / Indirect Firing• Coal Transport and Drying• Fuel Gas Pressure Regulation• Fuel Oil Pumping & Filtering• Fuel Oil Pressure & Viscosity Regulation• Gas Pressure & Oil Pressure/Temperature affect Boiler Load
  25. 25. FUEL PREPARATION SYSTEMMajor Equipment• Coal Mills - Tube Ball / Bowl / Impact• Raw Coal Feeders - Chain / Belt / Rotary / Gravimetric• Coal / Air Dampers, Gates & Discharge Valves• Fuel Oil Pumps & Heaters• Seal Air Fans• Coal Bunkers• Vapour Fans
  26. 26. FUEL PREPARATION SYSTEMProcess Regulation• Coal Flow - Raw Coal Feeder Speed• Coal/Air Temperature & Flow - Cold & Hot PA Flows
  27. 27. FUEL FIRING SYSTEM OFA OFA FF EA F FA (2) (3) Air Damper EF AA E OFA Over Fire Air EA End Air DE FA Fuel Air D AA Aux. Air Front Wall Coal BurnerCD (4) (1) Plan Fire Ball ScannerC (Corner Designation) LFO?HFO BurnerBCB HFO Burner Oil Flame ScannerABA HEA IgniterAA Typical Corner Arrangement for a Tangentially Fired System
  28. 28. FUEL FIRING SYSTEMProcess Performance Highlights• Fuel Firing - Front / Tangential• Fuel Oil Atomisation - Mechanical / Air / Steam• Flame Ignition• Air Distribution• Fuel Combustion
  29. 29. FUEL FIRING SYSTEMMajor Equipment• Burners• Ignitors• Flame Scanners• Burner Tilt Mechanism• Wind Box• Dampers
  30. 30. FUEL FIRING SYSTEMProcess Regulation• Furnace to Wind Box Differential Pressure• Fuel Air Flows• Fuel Firing• Emergency Shutdown• Flame Monitoring• Oil Support for Coal Flame Stability
  31. 31. BOILER MISCELLANEOUS SYSTEMSBoiler Auxiliary Cooling Water System• Ensures continuous supply of cooling water to Boiler & it’s auxiliaries• Consists of Overhead Tank, Pumps & Heat ExchangersChemical Dosing System• Prepares & supplies chemicals for treatment of Boiler Water• Consists of Preparation Tanks, Mixers & Metering Pumps
  32. 32. DEAERATION & FEED PUMPING SYSTEM Condensate from LP Heater To HP HP Heater Drains Aux. Steam Heaters CRH Steam Deaerator IPT ExtractionAux. Steam Steamfor Feed Storage TankPegging To HP Bypass Spray Hydrazine T o APRDS Dosing Spray Ammonia Recirculation Dosing Valve M Discharge Valve Boiler Feed Pumps Simplified Process Diagram
  33. 33. DEAERATION & FEED PUMPING SYSTEMProcess Performance Highlights• Boiler Water pre-heating & air removal• Maintain positive Suction Pressure for Feed Pumps• Feed Water Pumping to Boiler
  34. 34. DEAERATION & FEED PUMPING SYSTEMMajor Equipment• Boiler Feed Pumps• Hydraulic Coupling• Deaerator
  35. 35. DEAERATION & FEED PUMPING SYSTEMProcess Regulation• Deaerator Pressure• Deaerator Level• BFP Minimum Recirculation• Feed Pump Speed
  36. 36. STEAM TURBINE FUNDAMENTALS
  37. 37. LAWS OF THERMODYNAMICS• Conservation of Energy - Heat may be converted in to work and work may be converted in to heat, in accordance with a certain natural proportionality constant (ENERGY CAN NOT BE DESTROYED)• Not all of a given quantity of Heat can be converted in to useful Work, because of irreversbility in the process (ENTROPY OF THE UNIVERSE IS INCREASING)
  38. 38. BASIC RANKINE CYCLET Heat Available for Work Unavailable Heat S
  39. 39. IMPROVING RANKINE CYCLE• Superheating• Increased Pressure• Decreased Exhaust Pressure• Regenerative Feed Heating• Reheating
  40. 40. STEAM TURBINE TYPES• Condensing Turbine• Back Pressure Turbine• Regenerative Turbine•Controlled Extraction• No. of Cylinders• Speed - Constant / Variable• Single / Double Flow
  41. 41. TURBINE STEAM SYSTEMMainSteam ESV CV HP IP Turbine Turbine LP TurbineColdReheatSteam Condenser Hot Reheat Steam IV CV Extraction Steam Simplified Process Diagram
  42. 42. TURBINE STEAM SYSTEMMajor Equipment• Turbine - Casing, Rotor & Blades• Emergency Stop Valves• Control Valves• Condenser
  43. 43. TURBINE STEAM SYSTEMProcess Regulation• Steam Admission• Emergency Shutdown
  44. 44. REGENERATIVE FEED HEATING SYSTEM To From BFP To Boiler Discharge Deaerator LPT CRH Extraction Steam SteamToDeaerator LP HP HTR HTR LPT Condenser IPT Extraction Steam Gland Extrn. Leakoff Steam LP Steam HP HTR Minimum Makeup HTR Recirculation Hotwell To LPT Extraction Condenser LP Drain To GSC HTR CLR HP Condenser LP Flash Flash Tank Tank Condensate Extraction Pump Simplified Process Diagram
  45. 45. REGENERATIVE FEED HEATING SYSTEMProcess Performance Highlights• Pumping of Condensate from Hotwell to Deaerator•Gradual Heating of Feed Water Temperature• Minimise Heat Loss from the Cycle
  46. 46. REGENERATIVE FEED HEATING SYSTEMMajor Equipment• HP Heaters• LP Heaters• Drain Cooler• Condensate Extraction Pumps
  47. 47. REGENERATIVE FEED HEATING SYSTEMProcess Regulation• Hotwell Level• Heater Level• Minimum Flow through CEP & GSC
  48. 48. TURBINE GOVERNING & CONTROL SYSTEM Governing Oil System Turning Gear Jacking Condenser Oil Vacuum System System Lubricating Gland Turbine Oil Steam Drain System System System OIL SYSTEMS VACUUM SYSTEM WARM UP SYSTEM Functional Block Diagram
  49. 49. TURBINE GOVERNING & CONTROL SYSTEMProcess Performance Highlights• Shaft & Bearing Protection• Electro-hydraulic Governing• Maintain Vacuum in Condenser• Supply Steam to Turbine Glands• Warming up of Turbines and their Valves• Emergency Shutdown in case of Unsafe Conditions
  50. 50. TURBINE GOVERNING & CONTROL SYSTEMMajor Equipment• Oil Pumps, Turning Gear & Jacking Oil Pump• Hydraulic Actuators for Turbine Valves• Vacuum Pumps• Gland Steam Pressure Regulator• Oil Coolers & Temperature Regulator
  51. 51. TURBINE GOVERNING & CONTROL SYSTEMProcess Regulation• Speed / Load / Frequency Control• Gland Steam Pressure Control
  52. 52. TURBINE MISCELLANEOUS SYSTEMSCondenser Cooling Water System• Supplies Cooling Water Condensation of Turbine Exhaust SteamTurbine Auxiliary Cooling Water System• Ensures continuous supply of cooling water to Turbine & it’s auxiliaries• Consists of Overhead Tank, Pumps & Heat ExchangersChemical Dosing System• Prepares & supplies chemicals for treatment of Condensate• Consists of Preparation Tanks, Mixers & Metering Pumps
  53. 53. TURBINE MISCELLANEOUS SYSTEMS Condenser Cooling Water System CW Return HeaderCooling Condenser WaterboxTower To A B Unit#2 CW Sump CW Makeup Water CW Supply Header Circulating Water Pumps Simplified Process Diagram
  54. 54. TURBINE MISCELLANEOUS SYSTEMS Condenser Cooling Water SystemMajor Equipment• Cooling Towers• CW PumpsProcess Performance Highlights• Steam Condensation• Cooling of Condenser CW - Cooling Tower / LakeProcess Regulation• Condenser Tube Cleaning - Online / Back flushing
  55. 55. TURBINE BYPASS SYSTEMMainSteam To HPT Feed Water PRV Block Spray Valve Control ValveCRH From HPT HRH To IPT Condensate Condenser Simplified Process Diagram
  56. 56. TURBINE BYPASS SYSTEMProcess Performance Highlights• Enable Boiler Operation for Quick Re-start after Boiler Trip and during Turbine Start-up• Control MS Pressure after Turbine Trip or Sudden Load Throw-off
  57. 57. TURBINE BYPASS SYSTEMProcess Regulation• MS Pressure Reduction & Desuperheating• HRH Steam Pressure Reduction & Desuperheating
  58. 58. GENERATOR FUNDAMENTALS
  59. 59. WORKING PRINCIPLE• Converts Mechanical Energy in to Electrical Energy• Based on Electro-magnetic Induction E = 4.44 O FN volts E - e. m. f. O - Strength of Magnetic Field F - Frequency N - No. of Turns in a Stator Winding Coil F = Pn/120 P - No. of Poles n - Revolution per second of Rotor
  60. 60. GENERATOR EFFICIENCY & LOSSES• Efficiency = Output Electrical Energy Input Mechanical Energy• Losses - Bearing Loss, Copper Loss & Iron Loss• Typically Efficiency is 90-97%
  61. 61. GENERATOR & UNIT ELECTRICAL SYSTEM Metering & Protective Relays Generator Seal Transformer Oil System Generator Hydrogen Synchronising Cooling Sceme System Unit Field Stator Auxiliary Excitation Cooling Water Transformer System System ELECTRICAL SYSTEMS MECHANICAL SYSTEMS Generator Functional Block Diagram
  62. 62. GENERATOR & UNIT ELECTRICAL SYSTEM Isolator 132 KV Bus I 132 KV Bus II Circuit Breaker Unit GT Auxiliary Transformer From 11 kV From Station Station Bus Bus Generator 6.6 kV Unit Bus A 6.6 kV Unit Bus B Key One Line Diagram
  63. 63. GENERATOR & UNIT ELECTRICAL SYSTEMProcess Performance Highlights• Conversion of Mechanical Energy in to Electrical Energy• Field Excitation• Stator Winding Cooling by Distillate / Air• Rotor Winding Cooling by Hydrogen / Air• Hydrogen Sealing by Oil• Synchronisation & Voltage Transformation• Emergency Shutdown in case of Unsafe Conditions
  64. 64. GENERATOR & UNIT ELECTRICAL SYSTEMMajor Equipment• Generator - Stator, Rotor, Armature Windings, Field Windings• Field Excitation - Exciter (DC/AC), Static Rectifying Unit & AVR• Bus Ducts & Transformers• Circuit Breakers & Protective Relays• H2 Cooling - Fans, Dryers & Coolers• Stator Water Cooling - Pumps, Coolers & Overhead Tank• Seal Oil - Pumps, Coolers & Differential Pressure Regulator
  65. 65. GENERATOR & UNIT ELECTRICAL SYSTEMProcess Regulation• Field Excitation• Generator Synchrinisation• Voltage Regulation
  66. 66. POWER PLANTOPERATION & MAINTENANCE
  67. 67. OPERATION & MAINTENANCEEfficiency Calculations• Boiler Efficiency - Direct / Heat Loss Method• Turbine Heat Rate - Total Heat Supplied/ KWHR• Plant Heat Rate - Heat Supplied/ KWHR
  68. 68. OPERATION & MAINTENANCEFactors Affecting Plant Performance• Flue Gas Exit Temperature• Excess Air• Unburnt Fuel• Steam Temperature• Condenser Back Pressure• FW Temperature at Eco Inlet• Auxiliary Power Consumption• Make up Water Flow• Optimum Loading
  69. 69. OPERATION & MAINTENANCE• Start-up & Shutdown Monitoring• Trip Analysis - Boiler / Turbine / Generator• Equipment Run-Hour Monitoring• History Trending• Alarm Management• Division of Operational Responsibilities• Economic Load Allocation & Load Shedding (CPP)
  70. 70. POWER PLANTAUTOMATION & CONTROL
  71. 71. POWER PLANT AUTOMATION & CONTROLBurner Management System• Furnace Purge Supervision• Secondary Air Damper Modulation, On/Off Control and Supervision• Light/Heavy Oil On/Off Control and Supervision• Pulveriser and Feeder On/Off Control and Supervision• Flame Scanning• Overall Boiler Flame Failure Protection• Boiler Trip Protection
  72. 72. POWER PLANT AUTOMATION & CONTROLSoot Blower Sequential Control• Wall Blowers• Long Retractable Blowers• Air Heater Blowers
  73. 73. POWER PLANT AUTOMATION & CONTROLAutomatic Turbine Run-up System• Oil Supply Control - Turning Gear, Auxiliary Oil Pumps, Emergency Oil Pump, Jacking Oil Pump and Lube Oil Temperature• Condensate & Evacuation Control - Condensate Extraction Pumps, Gland Steam Pressure, Vacuum Pumps and Vacuum Breaker Valve• Turbine Control - Steam & Metal Temperature Matching, Warming up of HP ESV & CV, Steam Rolling & Acceleration and Auto Synchroniser
  74. 74. POWER PLANT AUTOMATION & CONTROLTurbine Stress Evaluator• Calculation of Actual and Permissible Thermal Stress Values• Comparison of Actual with Permissible Stress Values and Computation of Available Margin• Optimize Start up, Operation and Shut down
  75. 75. POWER PLANT AUTOMATION & CONTROLAutomatic Turbine Tester• Safety Devices - Remote Trip, Over-speed, Low Vacuum and Thrust Bearing• HP/IP Valves - HP Stop and Control Valves, and IP Stop and Control Valves
  76. 76. POWER PLANT AUTOMATION & CONTROLElectro-hydraulic Governing System• Speed Control• Load Control• Load Shedding• Initial Pressure Control
  77. 77. AUTOMATION & CONTROLCRITICAL CLOSED LOOPS• CMC - Boiler Follow / Turbine follow / Coordinated (Utility)• Header Pressure Control (CPP)• Combustion - Fuel / Air Flow• Steam Temperature• Drum Level• Furnace Draft
  78. 78. AUTOMATION & CONTROLOPEN LOOP CONTROL• Interlocking - Safe Startup / Shutdown• Protection - Emergency Shutdown (Trip)• Sequencial Control - Efficient Startup / ShutdownCRITICAL OPEN LOOPS• ID/FD /PA Fans• BFP
  79. 79. POWER PLANTINSTRUMENTATION
  80. 80. POWER PLANT INSTRUMENTATION• Temperature - T/C & RTD• Pressure• Level - DP / Displacement / Hydra Step Drum Level Indicator• Flow - DP / Annubar / Mag-flow• Turbine Supervisory - Vibration/ Expansion/ Axial Shift/ Eccentricity• Steam & Water Analysers - Conductivity/ pH/ DO2/ Silica• Gas Analysers - O2/ CO2/ CO (in Flue Gas) Pollution Monitor H2 Purity (in Generator)

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