Gas-liquid-interphase mass transfer coefficients kLa were measured for CO2-air-water and H2-air-water systems in a trickle bed with gas and liquid flowing cocurrently downward. Glass heads with diameters dp 0.0065

0.00475 and 0.00154 m were packed in a column of 0.042 m inside diameter. The gas-phase superficial velocities uG were 0.12-0.56m/s

and the liquid-phase superficial velocities uL were 0.003-0.04m/s. The volumetric mass transfer coefficients kL. were correlated with the physical properties of liquid(Sc number)

packing size

and flow conditions of gas and liquid

Three flow regimes obtained from the mass transfer study agreed with those obtained from fluid flow. The following correlations were obtained by regression analysis. Trickle-flow regime: Pulse-flow regime: