HOLDUP STRUCTURE IN HIGHLY VISCOUS NEWTONIAN AND NON-NEWTONIAN LIQUIDS IN BUBBLE COLUMNS

Abstract

Abstract Gas holdup structures in highly viscous glycerine and CMC solutions are studied in a 0.305 m diameter batch bubble column. The fractional gas holdups are determined using the dynamic gas disengagement method. Empirical correlations for the gas holdup based on data covering wide ranges of viscosities in Newtonian and pseudoplastic non-Newtonian solutions are presented. For highly viscous pseudoplastic solutions in small diameter columns, the gas holdup has a square root dependence on the diameter of the column. The absence of small bubbles is suggested to be a reason for the very low volumetric mass transfer coefficients in highly viscous solutions, reported in the literature.