Influence of oil‐atomized air on flow and combustion characteristics in a 300 MW_e down‐fired boiler

Abstract

Abstract A method of admitting oil‐atomized air into a furnace to adjust coal combustion in a down‐fired boiler is described. Experiments with a small‐scale furnace simulating a down‐fired, pulverized‐coal, 300‐MW e utility boiler were carried out at a single‐phase test facility to investigate the influence of oil‐atomized air on the aerodynamic field in the furnace. With the acceleration of oil by secondary air, the primary air/fuel can reach a more distant position with respect to the burner nozzle and the volume of the recirculation zone shrinks. Industrial experiments were also performed in a 300‐MW e full‐scale boiler. The gas temperature distribution along the primary air/fuel flow in the furnace and the gas components in the near‐wall region were measured with the dampers of the oil‐atomized air box open and closed. When open, the oil‐atomized air does not impede the ignition of the primary air/fuel and can carry the primary air/fuel to a position much deeper in the furnace, resulting in a lowered carbon content in the fly ash. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.