Bituminous coal combustion in a full-scale start-up ignition burner: Influence of the excess air ratio

A start-up ignition burner has been proposed to reduce oil fuel consumption during the firing-up process and partial-load operation. To investigate the influence of different excess air ratios on bituminous coal combustion in the start-up ignition burner, full-scale reacting-flow experiments were performed for an experiment setup. The ignition burner was identical to that normally used in an 800 MWe utility boiler. Gas temperature distributions in the burner were obtained for excess air ratios of 0.56, 0.75, 0.98 and 1.14 (corresponding to primary air velocities of 17, 23, 30 and 35 m/s). Coal burnout and the release of C and H were observed at the exit of the burner nozzle. Gases such as O2 and CO were measured at the center of the burner. A change in resistance was obtained within the burner.