MASS TRANSFER COEFFICIENTS BETWEEN GAS AND LIQUID PHASES IN PACKED COLUMNS

enhances the probability of the bubble coalescence and makes bubble larger.On the other hand, in the present study the dimention of the apparatus is far larger than that of the distributor and the depth of the liquids is shallow.Therefore, the probability of the bubble coalescence over the distributor is less than that of the Houghton et al.'s case, because the circulation of the liquid in the apparatus makes bubbles easy to apart each other.This fact is recognized when the porous plate distributor is used for liquid of group A and C in the bubble column with continuous liquid flow. SummaryBubbles which have been just generated from the porous plate are small and have an equal size, but sometime coalescence of these small bubbles occurs at a location slightly removed from the distributor, where the gas holdup is very large.Therefore, large and wide size distribution of bubbles are observed.This occurs easily in pure water and pure solvents.The surface active substances in water and solvents obstruct this coalescence of bubbles.In concentrated inorganic salt solutions, this obstruction is also recognized.For the extreme cases when no coalescence is observed and the coalescence occurs at the maximumrate, the correlations of the average bubble diameter and the conditions of bubble generation are obtained.