Effect of Parameters on Performance of Two-Stage Swirl-Flow Fluidized Bed Coal Combustors

Operating and design parameters which give the significant effect on the performance of the two-stage swirl-flow fluidized bed combustor were discussed. The combustion experiments of anthracite coal with a wide size distribution were carried out to investigate the influence of the various parameters on the performance in the laboratory scale combustor. The parameters considered were swirler nozzle diameter, number of swirler nozzles, combustor diameter of the upper stage and swirler nozzle velocity. The trapping rate of fines in the upper stage increased with reducing the swirler nozzle diameter and with increasing the number of swirler nozzles and the combustor diameter of the upper stage. At constant superficial gas velocity for the upper bed, the trapping rate of fines in the upper stage showed a maximum at the swirler nozzle velocity between 18 m/s and 24 m/s. The combustion efficiency improved as the result of the increase in the trapping rate and of the decrease in the carryover rate.