Gas-liquid mass transfer in three-phase inverse fluidized bed reactor with Newtonian and non-Newtonian fluids

Liquid-phase volumetric mass transfer coefficients, k(L)a were determined in three-phase inverse fluidized beds of low-density polyethylene (LDPE) and polypropylene (PP) spheres fluidized by a countercurrent How of air and Newtonian (water and glycerol solutions) or non-Newtonian liquids [carboxy methyl cellulose (CMC) solutions]. The effects of liquid and gas velocities, particle size, solid loading and addition of organic additives (glycerol and CMC) on the volumetric mass transfer coefficient, k(L)a were determined. The superficial liquid velocity had a weak effect on the mass transfer whereas the gas flow rate affected the mass transfer positively. k(L)a increased with increase in particle diameter and decreased with increase in initial bed height (solid loading). k(L)a decreased as the concentration of glycerol (viscosity) and CMC increased. Empirical correlations are presented to predict the gas liquid volumetric mass transfer coefficient in terms of operating variables. (C) 2009 Curtin University of Technology and John Wiley & Sons, Ltd.