Optimization Of Low Temperature Flue Gas Waste Heat Utilization System In 300MW Coal Fired Generating Units And Analysis Of Variable Operating Conditions

Boiler flue gas loss is the maximum heat loss,at 4%-8%,so the full use of exhaust heat can receive very substantial energy saving effect.In recent years,research units of domestic and foreign have carried on the in-depth research to recovery and utilization of waste heat from flue gas of coal-fired power plant boiler,and waste heat utilization forms are numerous.By setting the low temperature economizer after the air preheater,the use of waste heat to heat the condensate to improve the steam turbine extraction waste heat utilization form is the most extensive research and application,this way can achieve a certain energy saving effect.This paper takes a typical 330 MW circulation flow in bed unit as an example,in-depth analysis of the boiler tail flue gas heat transfer process of the existence of "energy mismatch" phenomenon,from the viewpoint of energy cascade uti lization theory,using the classical thermodynamic theory,the performance of the series type of low temperature economizer system,parallel type of low temperature economizer system and to enhance the level of low temperature economizer system and efficie nt flue gas heat design and off design system based on the in-depth analysis.The energy saving effects of the four systems are compared,and the operating characteristics of the four kinds of waste heat utilization system under different operating conditi ons are contrasted.In this paper,the thermal performance of the equipment,the energy saving nature of the unit,and the performance of the system are investigated.Based on the actual operation of the flue gas waste heat utilization unit,the limited corrosion rate theory and the maximization of the recovery of flue gas,the idea of low temperature economizer export smoke as far as possible to calculate the dew point of real time flue gas is put forward.An optimized control scheme based on BP neural network algorithm and genetic algorithm is designed,which ensures that the low temperature of the low temperature economizer is the lowest in the absence of low temperature corrosion,and the residual heat is maximized.The results of this study can provide a theoretical basis for the energy saving of 300 MW and above coal-fired units and the design of new units,and provide technical supports for the safe and efficient operation of the unit.