Effect of system parameters on phase holdups for an inverse fluidized bed

Abstract

Phase holdups for an inverse fluidized bed (IFB) have been studied using low density polypropylene (PP) particles for different system parameters viz. superficial gas velocities (U_g), ratio of bed volume to liquid (reactor) volume (V_b/V_r), and liquid recirculation velocities (U_lr). Gas phase holdup (e_g) is found to increase with increase in U_g for all V_b/V_r ratios with and without liquid recirculation. Without liquid recirculation, e_g decreased with increase in V_b/V_r ratio upto a certain V_b/V_r ratio for all U_g values and then increases with further increase in V_b/V_r ratios. While with liquid recirculation, e_g is found to be higher than the case of without liquid recirculation. Liquid phase holdup (e_l) and solid phase holdup (e_s) are both found to decrease with increase in U_g for all V_b/V_r ratios with and without liquid recirculation. Regression analysis based mathematical correlations are developed to predict e_g for different U_g, V_b/V_r, and U_lr values. Average absolute percent deviations of the developed correlations are found to be 7.90 and 7.39 which are less compared to the data available in the literature. Thus this study on phase holdups gives a clear insight providing a basis for the design of a three phase
IFB reactor.