Particle mass transfer coefficients for cocurrent gas-liquid flow in packed beds.

Abstract

Particle-liquid mass transfer coefficients were determined by measuring the rate of dissolution of benzoic acid into water in a packed bed column with downward cocurrent flows. The packing consisted of 6.35 mm Berl saddles coated with benzoic acid and fluorescent dye mixture. The water flow rate was varied between 2.1 and 98 kg/m2 sec and the air flow rate between 0.33 and 1.77 kg/m2 sec covering the gas continuous, transition, pulsing, and dispersed bubble flow regimes. The effect of the gas flow rate on the mass transfer coefficient is less important in the trickling and dispersed bubble flow regimes and becomes significant in the transition and pulsing flow regimes. Correlations in terms of modified Sherwood number and modified Reynolds number are presented.