PULVERIZED COAL BURNER, PULVERIZED COAL BOILER AND METHOD OF BURNING PULVERIZED COAL

摘要

The present invention is directed to a burner forpulverized coal. The burner has a coal duct for pulverizedcoal and primary combustion air and a secondary combustion airduct such that the coal, primary air and secondary air mixoutside the outlet nozzles of the duct in a mixing zone wherecombustion occurs. Coal distribution means in the coal ductcreate, adjacent the outlet nozzle, at least one outer zone offlow spaced from the coal duct axis and at least one innerzone of flow nearer the coal duct axis. These are means fordecreasing flow in the outer zone relative to the flow in theinner zone, prior to entering the mixing zone. To achievegood mixing, and promote NOx reduction, the coalconcentration in the outer zone is higher than in the innerzone.