COAL COMBUSTION CHARACTERISTICS IN A FLUIDIZED BED COMBUSTOR WITH A DREFT TUBE

Abstract

The effects of gas velocity ot draft tuve(3-6Umf), bed temperature(800-900)and excess air ratio(0-30%)on the total entrainment ratem overall combustion efficiency and heat transfer coefficient have been determined in an internally circulating fluidized bed combustor with a draft tube. The total entrainment rate increases with an increase in gas velocity to draft tube, but decreases with increasing bed temperature and excess air ratio. The overall combustion efficiency increases with incrreasing excess air ratio, but decrease with increasing gas velocity to draft tube. The overall combustion efficiency obtained in internally circulating fluidized beds was found to be somewhat higher than that in a bubbling fluidized bed combustor