In order to solve the problem of high NO

x

emission in W-flame boiler

the engineering experience of low nitrogen combustion technology in tangentially fired boiler is used for reference

based on air staged combustion

fuel staged combustion

dense-lean pulverized coal combustion and two-stage combustion air control

a low-nitrogen combustion combined retrofit scheme is proposed and verified by numerical simulation. The scheme has been successfully applied to the retrofit of a 600 MW unit boiler in a power plant. The application results show that the boiler NO

x

emission is reduced by more than 50% under the BMCR working condition after the retrofit

the boiler efficiency is improved

and the operating pressure of the SCR denitrification system is reduced

to a

void the secondary pollution problem caused by ammonia escape caused by excessive ammonia injection.