Effect of the separated overfire air location on the combustion optimization and NO reduction of a 600 MW FW down-fired utility boiler with a novel combustion system

A novel combustion system has been applied to a 600 MWe down-fired boiler to reduce NOx emissions without producing an obvious increase in the carbon content of fly ash. The system mainly includes moving fuel-lean nozzles from the arches to the front/rear walls, and re-arranging the staged air, as well as introducing separated-over-fire air (SOFA). This paper evaluates the effects of the SOFA locations (on the arches, on the throat, and on the...