WALL-TO-LIQUID MASS-TRANSFER IN LIQUID-SOLID AND GAS-LIQUID-SOLID FLUIDIZED-BEDS

Rates of mass transfer between a liquid and a surface which is axially immersed in fluidized beds are measured. Liquid-solid and gas-liquid- solid beds of both inert and active conducting particles are considere d. Variables used in the experiments are liquid superficial velocity, particle size, and gas superficial velocity. The wall-to-liquid mass t ransfer coefficients in liquid-solid fluidized beds are increased with the liquid superficial velocity and particle size. The liquid holdup at which the maximum mass transfer occurs, is decreased with particle size. The mass transfer coefficients in gas-liquid-solid fluidized bed s are slightly decreased with the gas superficial velocity. The mass t ransfer coefficients in terms of Chilton-Colburn factor can be well co rrelated with the modified Reynolds number.