GAS-LIQUID MASS-TRANSFER IN JET BUBBLE-COLUMN

The jet bubble column consists of a conical entrance section which exp ands to a cylindrical column. Gas and liquid are co-currently introduc ed at the bottom of the column by a small diameter inlet pipe which ac ts like an ejector. The kinetic energy of the gas and liquid jet toget her with the conical geometry at the lower section of the column cause the formation and dispersion of small bubbles. Gas-liquid mass transf er in the jet bubble column (61 cm diameter) was measured by a dynamic response technique, in which a step change was made in the gas phase oxygen concentration and the aqueous dissolved oxygen concentration re sponse was measured at various axial and radial locations. It was foun d that a continuous stirred tank reactor model could be used to evalua te experimental results. The volumetric mass transfer coefficient in t his type of system was found to increase with increasing gas flow rate and was about 1.5 times larger than the values obtained at similar co nditions in conventional bubble columns. Preliminary measurements and calculations indicate negligible effects of liquid velocity and bed he ight on the mass transfer coefficient.