A highly elevated mass transfer rate process for three-phase, liquid-continuous fluidized beds

Average gas holdup and gas-to-liquid mass transfer in three-phase fluidized beds with non-Newtonian fluids were studied. The effects of liquid propert y, gas distributor type and magnetic field intensity on mass transfer coeff icient and overall gas holdup were examined. The volumetric gas-to-liquid m ass transfer coefficient was determined by fitting the oxygen concentration profile data across the bed to the axial dispersion model, The average gas holdup and mass transfer coefficient were all correlated with operating pa rameters including gas velocity and effective viscosity. Experimental results showed that a three-fold increase in mass transfer coe fficient and a two-fold increase in average gas holdup were observed with p roperly designed liquid property and gas distributor. A modified process wa s developed to highly elevate the volumetric gas-to-liquid mass transfer ra te. The bubble coalescing property of three-phase fluidized beds with small particles is eliminated, and its application to biotechnology and enzyme-c atalyzed processes with high gas-to-liquid mass transfer rate could be achi eved. (C) 2001 Elsevier Science B.V. All rights reserved.