Study of Hydrodynamics and Dry Beneficiation Characteristics of Coal in the Riser of a Circulating Fluidized Bed Reactor

Abstract

Dry beneficiation is an effective way of reducing the ash content of coal especially in the water scarce region. Fast fluidization region was used to carry out some exploratory investigations with raw coal to reduce the ash below a 12% level from a feed ash of 43%. As the coal was fluidized in the riser of a fast fluidized bed, the heavier and coarse particles generally settled at the bottom in a dense zone of the riser while the finer and lighter particles were entrained to the top dilute zone and, using a cyclone, were fed back to the bottom of the circulating fluidized bed (CFB) riser column. Most of the low-ash fine-size coals being lighter moved up to the riser, where most of the beneficiation occurred.