COMBINED-CYCLE PLANT Russian patent published in 1998 - IPC

FIELD: power engineering; redesigning and retrofitting of power units at thermal power stations for users of low-potential heat. SUBSTANCE: plant has known members of steam-turbine unit and those of combined-cycle plant 1-17 including steam boiler 1, with air heater 2 and forced-draft equipment 3-9, steam-turbine unit 10 with steam-condensate circuit equipment 11-13, gas-turbine unit 14-16 with exhaust gas duct 17 connected to draft system of boiler, as well as newly introduced components 18-26 including heat exchanger 19, mixer 22, control elements 20, 24, 26, and air ducts 18, 23, 25. Circulating loop 18 is used to control oxidizer flow to power unit in addition to gas-turbine exhaust gas. Introduction of cool air 23 to exhaust gas duct 17 limits temperature in boiler draft system. Boiler bypass 25 functions to ensure deep adjustment of steam-turbine section load and separate operation of gas turbine in case of shut-off of fuel supply to boiler. Exhaust gas dump from gas turbine to boiler is effected over circuit using air as intermediate coolant. EFFECT: improved design and operating characteristics, reduced amount of work and prime cost, especially in redesigning operating steam-turbine units. 3 cl, 1 dwg