Comprehensive Optimization Design of the Tail Heating Surface in Utility Boiler

Based on detailed analysis of the traditional utility boiler tail heating surface and the layout scheme of the conventional low-temperature economizer,this paper proposes a new type of power plant boiler tail heating surface optimal layout program. Thereby,hierarchically arrange the air preheater,install the economizer and high-temperature air preheater in the separated flue,fix the two-staged air preheaters in the main flue and the low-temperature economizer between the two-staged air preheaters. In combination with a typical 1000MW unit power station boiler,the heat transfer characteristics and the energy-saving effect of the proposed method are analyzed. Results indicate that the hot air temperature can be increased by nearly 20℃,and the low-temperature economizer can save the extracted steam of the #5 regenerative heater from the steam turbine. The saving of standard coal equivalent( SCE) can reach at 4. 6 g /( kW·h). The annual amount of coal savings can approximate 26,000 tons and 26 million RMB per year( with 5500hours unit running time).