HYDRODYNAMICS AND MASS-TRANSFER IN AN UPWARD VENTURI BUBBLE COLUMN COMBINATION

The hydrodynamics and mass transfer characteristics of a venturi/bubble column combination were studied at high liquid superficial velocities of up to 0.35 m/s. The gas hold-up was increased by 50% to 150% and the overall volumetric mass transfer coefficient was tripled when the venturi was used as "gas distributor" instead of a porous distributor. A correlation of the overall volumetric mass transfer coefficient (K(L)a) with the gas hold-up, valid for gas hold-ups as high as 0.3, was proposed for the cylindrical bubble column section. The energy consumption per mole of oxygen transferred was lower than with most distributors and the oxygen transfer rate per unit of reactor volume was higher than in a bubble column with a porous distributor. The venturi/bubble column combination is a compact and efficient system which does not have the operating problems of systems which require internals.