Solid‐liquid mass transfer in packed beds with cocurrent gas‐liquid downflow

Local instantaneous solid‐liquid mass transfer coefficients were measured in two‐phase gas‐liquid downflow through packed columns for 3 × 3 mm and 6 × 6 mm cylinders. An electrochemical technique was used. Liquid flow rates from 3.0 to 26.6 kg/m2·s and gas flow rates from 0.07 to 1.16 kg/m2·s covered the gas‐continuous, ripple, and pulse flow regimes. Time‐averaged mass transfer coefficients in trickle flow and in pulse flow for the pulse proper and the base (outside the pulse) were found to increase with increasing gas and liquid rates. Correlations are presented in terms of liquid phase Reynolds numbers and in terms of Kolmogoroff numbers. The mass transfer coefficients in the pulse were found to correspond closely to the coefficients that would be attained in the dispersed bubble flow regime.