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 (Ug), ratio of bed volume to liquid (reactor) volume (Vb/Vr), and liquid recirculation velocities (Ulr). Gas phase holdup (g) is found to increase with increase in Ug for all Vb/Vr ratios with and without liquid recirculation. Without liquid recirculation, g decreased with increase in Vb/Vr ratio upto a certain Vb/Vr ratio for all Ug values and then increases with further increase in Vb/Vr ratios. While with liquid recirculation, g is found to be higher than the case of without liquid recirculation. Liquid phase holdup (l) and solid phase holdup (s) are both found to decrease with increase in Ug for all Vb/Vr ratios with and without liquid recirculation. Regression analysis based mathematical correlations are developed to predict g for different Ug, Vb/Vr, and Ulr 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.