METHOD FOR HEAT EXTRACTION FROM GAS-FIRED BOILER AND STEAM BOILER IMPLEMENTING IT Russian patent published in 2000 - IPC

FIELD: steam boilers of thermal power stations with extraction economizers. SUBSTANCE: method may be used in case of increase in heat loads of pre-peak heat-supply systems. Delivery water is heated in extraction economizer partially by exhaust heat of stack gases extracted in vicinity of boiler flue during high-temperature intervals. Water is preheated prior to being supplied to heating economizer by heat partially extracted from blast passed through air heater; thermal capacity of heating economized is enhanced by shutting off feedwater line of boiler main economizer or some of its heat-transfer surfaces. For implementing proposed method, heating economizer is installed upstream of air heater along stack-gas flow path. In the process, heated circuit of air-to-water heat exchanger is connected to pipeline passing delivery water to heating economizer; heating circuit of heat exchanger is inserted in air line passing hot blast air from air heater to boiler furnace; boiler main economizer is provided, in addition, with bypass line. EFFECT: improved thermal capacity of heating economizer. 7 cl, 5 dwg