According to the characteristics of circulating fluidized bed(CFB)boilers

optimization on selective non-catalytic reduction(SNCR)denitrification system applying urea as the reducing agent was conducted.Numerical simulation results indicate that

spraying the injecting reducing agent from the upper side of the separator inlet to the inner side can result in higher reducing agent's efficiency;decreasing the urea solution concentration from 50%to 10%

the SNCR system can be operated without heat tracing system;the metering pump can make the flow rate control more accuracy for the reducing agent solution with small flow rate.The optimized SNCR system was applied in four 130t/h CFB boilers of a power plant.The measurement shows that

denitrification efficiency of the SNCR system reaches up to more than 50%

when the orignial NOx emission ranges from 120mg/m3 to 130mg/m3

and the construction cost and operation cost of the system are only 32yuan/kWh and 0.145fen/kWh

respectively.