power-plant-basics
- 1. POWER GENERATION PROCESS BASICS
- 2. BOILER / STEAM TURBO-GENERATOR UTILITY PLANT 40% Steam Condenser 20% Stack Lake Steam 6% Aux. Power + Losses 34% Electricity 100% Fuel Air Boiler Steam Turbine Generator Transmission THERMAL EFFICIENCY - 34%
- 3. BOILER / STEAM TURBINE-GENERATOR INDUSTRIAL CO-GENERATION Process Steam 65% 15% Process Plant Stack Steam 5% Aux. Power + Losses 15% Electricity Fuel 100% Air Boiler Steam Turbine Generator Transmission THERMAL EFFICIENCY - 80%
- 4. SIMPLE CYCLE COMBUSTION (GAS) TURBINE 57-62% 100% Fuel Stack Combuster 3% Aux Power + Losses 35-40% Electricity Air Compressor Turbine Generator Transmission THERMAL EFFICIENCY - 35-40%
- 5. GAS TURBINE INDUSTRIAL CO-GENERATION PLANT 20% Stack Stack Supplementary/ Auxiliary Fuel (Optional) Process Steam Process Plant 100% Fuel Combuster Exhaust Gas Air Compressor Turbine Generator Transmission
- 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% Electricity Air 6% Aux. Power + Losses 35-40% Electricity Compressor Turbine Generator Transmission Thermal Efficiency - 45-55%
- 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. CAPTIVE POWER PLANT - FUNCTIONAL BLOCK DIAGRAM Switch Yard System Ash Handling System Station Electrical System Steam & Water Air & Flue Gas BOILER Fuel Preparation Fuel Firing Steam UNIT#2 UNIT#3 TG HP & LP Heaters Supervisory & Control Generator & Electrical Miscellaneous Systems BFP’s & Deaerator System Fuel Handling System DM Plant Station Miscellaneous Systems
- 10. BASIC DIAGRAM OF A BOILER Steam Water Steam / Water System Blowdown Fuel Flue Gas Mixing of Heat Transfer Fuel & Air Surface Furnace Air Ash
- 11. SALIENT FEATURES OF MODERN INDUSTRIAL & UTILITY BOILER • STEAM BOILER • WATER TUBE • SUPERHEATED STEAM • HIGH PRESSURE • WATER COOLED FURNACE • WATER CIRCULATION
- 12. COMBUSTION REQUIREMENTS Sufficient Combustion Air Temperature Fuel Combustion Mixing within above is Time Flammable Ignition Gasified Temperature Range Point Turbulence 3 T’s of Combustion
- 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. 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 Water Down Comers Flue Gas Economiser Feed Water Furnace Flue Gas Water Wall Out to Risers Air Heater Bottom Ring Header Simplified Process Diagram
- 15. BOILER WATER & STEAM SYSTEM Process 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. BOILER WATER & STEAM SYSTEM Major 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. BOILER WATER & STEAM SYSTEM Process 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. AIR & FLUE GAS SYSTEM To Air Cooled PA FAN A To Hot To Cold Guns 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. AIR & FLUE GAS SYSTEM Process 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. AIR & FLUE GAS SYSTEM Major 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. AIR & FLUE GAS SYSTEM Process 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. FUEL PREPARATION SYSTEM - COAL Raw Coal Bunker To Mill Discharge Valves To Hot PA Other Coal Feeder Mills Coal+Air to Burners Mill A Cold PA To Other Mills To Other Mills Seal Air Fans Simplified Process Diagram
- 23. FUEL PREPARATION SYSTEM - GAS/OIL Fuel Gas Supply 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. FUEL PREPARATION SYSTEM Process 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. FUEL PREPARATION SYSTEM Major 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. FUEL PREPARATION SYSTEM Process Regulation • Coal Flow - Raw Coal Feeder Speed • Coal/Air Temperature & Flow - Cold & Hot PA Flows
- 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 Burner CD (4) (1) Fire Ball Scanner Plan C (Corner Designation) LFO?HFO Burner BC B HFO Burner Oil Flame Scanner AB A HEA Igniter AA Typical Corner Arrangement for a Tangentially Fired System
- 28. FUEL FIRING SYSTEM Process Performance Highlights • Fuel Firing - Front / Tangential • Fuel Oil Atomisation - Mechanical / Air / Steam • Flame Ignition • Air Distribution • Fuel Combustion
- 29. FUEL FIRING SYSTEM Major Equipment • Burners • Ignitors • Flame Scanners • Burner Tilt Mechanism • Wind Box • Dampers
- 30. FUEL FIRING SYSTEM Process Regulation • Furnace to Wind Box Differential Pressure • Fuel Air Flows • Fuel Firing • Emergency Shutdown • Flame Monitoring • Oil Support for Coal Flame Stability
- 31. BOILER MISCELLANEOUS SYSTEMS Boiler Auxiliary Cooling Water System • Ensures continuous supply of cooling water to Boiler & it’s auxiliaries • Consists of Overhead Tank, Pumps & Heat Exchangers Chemical Dosing System • Prepares & supplies chemicals for treatment of Boiler Water • Consists of Preparation Tanks, Mixers & Metering Pumps
- 32. DEAERATION & FEED PUMPING SYSTEM Condensate from LP Heater To HP HP Heater Drains Aux. Steam Heaters CRH Steam Deaerator IPT Extraction Aux. Steam Steam for Feed Storage Tank Pegging To HP Bypass Spray Hydrazine T o APRDS Dosing Spray Ammonia Recirculation Dosing Valve M Discharge Valve Boiler Feed Pumps Simplified Process Diagram
- 33. DEAERATION & FEED PUMPING SYSTEM Process Performance Highlights • Boiler Water pre-heating & air removal • Maintain positive Suction Pressure for Feed Pumps • Feed Water Pumping to Boiler
- 34. DEAERATION & FEED PUMPING SYSTEM Major Equipment • Boiler Feed Pumps • Hydraulic Coupling • Deaerator
- 35. DEAERATION & FEED PUMPING SYSTEM Process Regulation • Deaerator Pressure • Deaerator Level • BFP Minimum Recirculation • Feed Pump Speed
- 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. BASIC RANKINE CYCLE T Heat Available for Work Unavailable Heat S
- 39. IMPROVING RANKINE CYCLE • Superheating • Increased Pressure • Decreased Exhaust Pressure • Regenerative Feed Heating • Reheating
- 40. STEAM TURBINE TYPES • Condensing Turbine • Back Pressure Turbine • Regenerative Turbine •Controlled Extraction • No. of Cylinders • Speed - Constant / Variable • Single / Double Flow
- 41. TURBINE STEAM SYSTEM Main Steam ESV CV HP IP Turbine Turbine LP Turbine Cold Reheat Steam Condenser Hot Reheat Steam IV CV Extraction Steam Simplified Process Diagram
- 42. TURBINE STEAM SYSTEM Major Equipment • Turbine - Casing, Rotor & Blades • Emergency Stop Valves • Control Valves • Condenser
- 43. TURBINE STEAM SYSTEM Process Regulation • Steam Admission • Emergency Shutdown
- 44. REGENERATIVE FEED HEATING SYSTEM To From BFP To Boiler Discharge Deaerator LPT CRH Extraction Steam Steam To Deaerator LP HP HTR HTR LPT Condenser IPT Extraction Steam Gland Extrn. Leakoff Steam LP Steam HP HTR Minimum Makeup HTR Recirculation Hotwell LPT Extraction To Condenser LP Drain To GSC HTR CLR HP Condenser LP Flash Flash Tank Tank Condensate Extraction Pump Simplified Process Diagram
- 45. REGENERATIVE FEED HEATING SYSTEM Process Performance Highlights • Pumping of Condensate from Hotwell to Deaerator •Gradual Heating of Feed Water Temperature • Minimise Heat Loss from the Cycle
- 46. REGENERATIVE FEED HEATING SYSTEM Major Equipment • HP Heaters • LP Heaters • Drain Cooler • Condensate Extraction Pumps
- 47. REGENERATIVE FEED HEATING SYSTEM Process Regulation • Hotwell Level • Heater Level • Minimum Flow through CEP & GSC
- 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. TURBINE GOVERNING & CONTROL SYSTEM Process 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. TURBINE GOVERNING & CONTROL SYSTEM Major Equipment • Oil Pumps, Turning Gear & Jacking Oil Pump • Hydraulic Actuators for Turbine Valves • Vacuum Pumps • Gland Steam Pressure Regulator • Oil Coolers & Temperature Regulator
- 51. TURBINE GOVERNING & CONTROL SYSTEM Process Regulation • Speed / Load / Frequency Control • Gland Steam Pressure Control
- 52. TURBINE MISCELLANEOUS SYSTEMS Condenser Cooling Water System • Supplies Cooling Water Condensation of Turbine Exhaust Steam Turbine Auxiliary Cooling Water System • Ensures continuous supply of cooling water to Turbine & it’s auxiliaries • Consists of Overhead Tank, Pumps & Heat Exchangers Chemical Dosing System • Prepares & supplies chemicals for treatment of Condensate • Consists of Preparation Tanks, Mixers & Metering Pumps
- 53. TURBINE MISCELLANEOUS SYSTEMS Condenser Cooling Water System CW Return Header Cooling Condenser Waterbox Tower To A B Unit#2 CW Sump CW Makeup Water CW Supply Header Circulating Water Pumps Simplified Process Diagram
- 54. TURBINE MISCELLANEOUS SYSTEMS Condenser Cooling Water System Major Equipment • Cooling Towers • CW Pumps Process Performance Highlights • Steam Condensation • Cooling of Condenser CW - Cooling Tower / Lake Process Regulation • Condenser Tube Cleaning - Online / Back flushing
- 55. TURBINE BYPASS SYSTEM Main Steam To HPT Feed Water PRV Block Spray Valve Control Valve CRH From HPT HRH To IPT Condensate Condenser Simplified Process Diagram
- 56. TURBINE BYPASS SYSTEM Process 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. TURBINE BYPASS SYSTEM Process Regulation • MS Pressure Reduction & Desuperheating • HRH Steam Pressure Reduction & Desuperheating
- 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. GENERATOR EFFICIENCY & LOSSES • Efficiency = Output Electrical Energy Input Mechanical Energy • Losses - Bearing Loss, Copper Loss & Iron Loss • Typically Efficiency is 90-97%
- 61. GENERATOR & UNIT ELECTRICAL SYSTEM Metering & Protective Relays Seal Generator Oil Transformer 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. 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. GENERATOR & UNIT ELECTRICAL SYSTEM Process 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. GENERATOR & UNIT ELECTRICAL SYSTEM Major 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. GENERATOR & UNIT ELECTRICAL SYSTEM Process Regulation • Field Excitation • Generator Synchrinisation • Voltage Regulation
- 66. POWER PLANT OPERATION & MAINTENANCE
- 67. OPERATION & MAINTENANCE Efficiency Calculations • Boiler Efficiency - Direct / Heat Loss Method • Turbine Heat Rate - Total Heat Supplied/ KWHR • Plant Heat Rate - Heat Supplied/ KWHR
- 68. OPERATION & MAINTENANCE Factors 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. 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. POWER PLANT AUTOMATION & CONTROL
- 71. POWER PLANT AUTOMATION & CONTROL Burner 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. POWER PLANT AUTOMATION & CONTROL Soot Blower Sequential Control • Wall Blowers • Long Retractable Blowers • Air Heater Blowers
- 73. POWER PLANT AUTOMATION & CONTROL Automatic 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. POWER PLANT AUTOMATION & CONTROL Turbine 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. POWER PLANT AUTOMATION & CONTROL Automatic 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. POWER PLANT AUTOMATION & CONTROL Electro-hydraulic Governing System • Speed Control • Load Control • Load Shedding • Initial Pressure Control
- 77. AUTOMATION & CONTROL CRITICAL CLOSED LOOPS • CMC - Boiler Follow / Turbine follow / Coordinated (Utility) • Header Pressure Control (CPP) • Combustion - Fuel / Air Flow • Steam Temperature • Drum Level • Furnace Draft
- 78. AUTOMATION & CONTROL OPEN LOOP CONTROL • Interlocking - Safe Startup / Shutdown • Protection - Emergency Shutdown (Trip) • Sequencial Control - Efficient Startup / Shutdown CRITICAL OPEN LOOPS • ID/FD /PA Fans • BFP
- 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)