Cylinder surface-to-liquid mass transfer in three-phase fluidized beds

In the present study, the cylinder surface-to-liquid mass transfer coeffici ent was measured in three -phase fluidized beds of 82 mm O. D., with glass beads(average diameter; 2.2-5.2 mm) and alumina beads (average diameter; 0. 75-3.0 mm) as fluidized particles, using the limiting current method. One o f the cylinder electrodes used was vertically inserted along the centerline of the fluidized beds and the other was horizontally set in the transverse direction of the column cross section. The outside diameter of the two ele ctrodes was commonly 20 mm. The effect of operating conditions such as liqu id velocity, gas velocity and particle diameter on the mass transfer coeffi cient was investigated. Unified correlations were developed from the measured surface-to-liquid mas s transfer coefficients for the liquid-solid and three-phase fluidized beds in terms of the modified Colburn j-factor, or in terms of the specific pow er group based on the energy dissipation rate per unit mass of liquid. The presence of an analogy was confirmed between the mass transfer and heat tra nsfer through the liquid film on the cylinder surface.