Low-NO_x Combustion Technology Optimization On 600MW Tangential Firing Boiler Of Shenhua Coal

With the development of Chinese society environmental consciousness,the environmental emissions standards of thermal power units also become increasingly stricter,the thermal power plants are in urgent need of better technology to control and reduce NO_X(nitrogen oxide)emission,to meet further requirements of reducing NO_X emission.At present,among the technologies of NO_X emission control,the air-staged combustion technology is used the most commonly in the thermal coal-fired boilers,because of better emission reduction,low investment costs,and smaller scope of renovation.This paper will introduce the research on optimization of air-staged combustion technology in tangentially fired boiler,by analyzing the main effect factors that control the NO_X generation of air-staged combustion technology,we propose some technical measures to realize further NO_X emission reduction,while it has little effect on the main operation indexes of the boiler.It includes reducing the height of the main combustion zone,to prolong the reduction reaction time of pulverized coal in the furnace at high load,and controlling the excess air coefficient at low load,at the same time,it can effectively control the problems of coking and high-temperature corrosion.Also we validate the feasibility of the optimized program through numerical simulation trials and hot trials.After transform in NO.2 boiler of one power plant,the NO_X emission value is not more than 100mg/m~3(dry state,6%oxygen amount)at high load,and not more than 150mg/m~3(dry state,6%oxygen amount)under full load,the boiler efficiency is better than the design target.The optimized program has transform application prospect in the same type of four corner tangentially fired boilers.