Studies on Bed Density in a Gas-Vibro Fluidized Bed for Coal Cleaning

摘要

Dry coal beneficiation has played a vital role during the initial stage of coal cleaning in recent years. Successful utilization of a gas–solid fluidized bed for >6 mm coal cleaning motivates scholars to explore the possibility of fine coal cleaning using dry beneficiation methods. In this study, pulsed flow was introduced into a fluidized bed to optimize bubble behavior, thus improving the density stability. The equation of minimum fluidization velocity (Umfp) in a gas-vibro fluidized bed for coal preparation was investigated theoretically. An equation has been proposed for predicting Umfp while considering changes in the friction coefficient (Cf) in the gas-vibro fluidized bed. Based on two-phase theory, the correlation of bed density was determined by analyzing the bubble behavior in the gas-vibro fluidized bed. The theoretical bed density was then compared with experimental data of the bed density and separation density. The predicted bed density in monodisperse and binary dense medium systems was found to be consistent with the experimental results. Overall, the equation of bed density is suitable for estimating the separation density in the gas-vibro fluidized bed.