Improving the Fluidization Hydrodynamics of Cohesive Powder Using Pulsed Flow.

Abstract

Fine powders, despite their advantageous high surface area characteristics, often exhibit poor fluidization behavior due to their inherent cohesiveness. This cohesiveness leads to the evolution of structural irregularities, such as cracks and channels, resulting in unpredictable fluidization behavior and poor gas-solid interphase mixing. This study explores the potential of square-wave pulsed flow to enhance the fluidization of highly cohesive activated carbon powder, which is widely used due to its exceptional adsorptive properties. The effect of pulsation frequencies ranging from 0.025 to 0.25 Hz on fluidization hydrodynamics was assessed by analyzing pressure drop transients across the bed. Our results reveal that pulsed flow effectively delays the onset of structural nonhomogeneities, extending the stable operating range by up to four times compared to that of conventional, unassisted fluidization. High-frequency pulsations showed superior efficacy, highlighting the potential of pulsed flow for improving the fluidization behavior of cohesive powders.