PREDICTING BED VOIDAGE IN SOLID-LIQUID FLUIDIZATION

Previously published solid-liquid fluidization data and new experimental data were correlated to develop an explicit expression for bed voidage, s, in solid-liquid systems. Based on the observed deviation between the voidage predicted by the Richardson-Zaki18) equation (sRZ) and the actual voidage, this new correlation assumes the form a £PK + (1 — £pk)8rz exp(b(l — £rz)) whereA = 2.2n 4-8dPjD and B = 2An. sPKis the “packed” bed or the static bed voidage (i.e., s when the superficial liquid velocity, UL, is zero), n is the Richardson-Zaki18) exponent, and dP/D is the particle diameter-to-column diameter ratio. A total of 811 data points were correlated with Reynolds numbers based on terminal velocity, Ret, ranging from 0.7 to 3200. The correlation satisfactorily predicts voidage with a standard deviation of less than 5%. © 1990, The Society of Chemical Engineers, Japan. All rights reserved.