Power Boiler Operation Principle Part 1 บรรยาย โดย วศ. สหเทพ จ้อยประดิษฐ์ วศ. 8 แผนกวิศวกรรมหม้อน้ า กฟผ. 1 Power Plant Type in EGAT • Combine Cycle Power Plant Hoz. flow Ver. flow Sub. Cri Pressure Sup. Cri Pressure • Thermal Power Plant 2 General knowledge of Combined Cycle Power Plant Configuration of Combined Cycle Power Plant Bypass Stack Main Stack Steam Turbine, Generator, BOP Air Intake Duct Steam Turbine Gas Turbine Generator Generator HRSG 3 Simple Cycle & Combined Cycle Power Plant Combined Cycle Power Plant (CCPP) Simple Cycle Power Plant(SCPP) Gas Turbine Generation Steam Turbine Generation Low temp. exhaust Gas Fuel Air Intake Exhaust Steam Heat Recovery Steam Generator Combustor Compressor Steam Exhaust Hot Gas Air Gas Turbine Generator * SCPP : Simple Cycle Power Plant * CCPP : Combined Cycle Power Plant Steam Turbine Generator 4 HRSG BASIC CONCEPT cold exhaust gas Temp . cold water in hot source (exhaust gas) out steam hot exhaust gas out cold source (water/steam) in height 5 HEAT EXCHANGERS ARRANGEMENT cold exhaust gas cold water economiser drum evaporator superheater hot exhaust gas superheated steam 6 NATURAL CIRCULATION Water (V1) Water + Steam (V2) Steam drum b Natural Circulation by thermosiphon effect, because specific volume V1 < V2 Pa > Pb a Evaporator 7 RANKINE CYCLE • AB : water heating in economizer : 20 % of exchange • BC : water boiling in evaporator :65 % of exchange • CD : steam overheating in superheater :15 % of exchange • DE : steam turbine + generator • EA : condenser + feed pump Work = area Temp. D B A C E Entropy 8 PINCH POINT • • • • Smallest difference of temperature between hot gas and cold water Location at evaporator outlet, where the heat exchange efficiency is the lowest Gas temperature curve swings around pinch point usual value : 8-12°C –< 8°C : need of too much exchange area –> 12°C : low cycle efficiency T SHT Evapo Econo L 9 APPROACH • Difference between the drum • • temperature in drum (saturation) and temperature at economiser outlet Must be positive to avoid steaming, but efficiency is better if approach is small (few degrees) Steaming is controlled by throttling at the outlet of the economiser (location of FW control valve) • Special control valve (flashing) T SHT Evapo Econo L 10 Heat Recovery Steam Generator * The function of DRUM is : Composing of flow circuit for boiler water/steam Separating mixed water/steam inflowing from riser pipe Steam Drum Storage of boiler water discharging solid existing within evaporator system through blowdown Water Evaporator 11 General knowledge about Combined Cycle Power Plant Drum Type & Once-Through Type Drum Circulation Once Through 12 Heat Recovery Steam Generator Design of Drum Type HRSG [ Steam Cycle ] Steam Drums Steam Silencer • Single Pressure • Dual Pressure • Triple Pressure [ Arrangement ] • Horizontal • Vertical [ Circulation ] • Natural • Once through • Forced Outlet Duct & Stack Heating Elements Duct Burner Area Inlet Duct 13 Heat Recovery Steam Generator Horizontal HRSG - Design Features ■ Vertical Tubes Arrangement ■ Horizontal Gas Flow ■ Natural Circulation Evaporators ■ Staggered Tube Arrangement ■ All-Welded Tube-to-Header Construction ■ Internal Insulation and Liners ■ All Welded Cold Outer Casing ■ Integral Support Structure ■ Bottom and Top Support 14 Heat Recovery Steam Generator Vertical HRSG - Design Features ■ Horizontal Tubes Arrangement ■ Vertical Gas Flow ■ Forced Circulation ■ In-Line Tube Arrangement ■ All-Welded Tube-to-Header Construction ■ Internal Insulation and Liners ■ All-Welded Cold Outer Casing ■ Integral Support Structure ■ Top Support 15 Configuration of Thermal Power Plant By Circulation System 16 Configuration of Thermal Power Plant by Firing Arrangement 17 Thermal Power Plant 18 19 Thermal Power Plant 20
© Copyright 2024 ExpyDoc
