After low-NOxburner transformation of a supercritical 600 MW swirl-opposed firing boiler

the CO concentration in the tail became high and the NOxemission didn't reach the expectations due improper operation adjustment.The analysis shows that the uneven distribution of oxygen along the width and depth direction of the furnace is the main cause.Thus

according to the structural characteristics of the retrofited burners

the burner parameters were optimized.After that

the CO concentration at rated load reduced from2 000μL/L to lower than 100μL/L

the carbon content in fly ash reduced to below 0.5%

the boiler efficiency increased by 0.8%

and the NOx emission concentration dropped from 400~450 mg/m3 to about250mg/m3.