TRANSITIONAL DROP SIZE DISTRIBUTIONS IN GAS AGITATED LIQUID-LIQUID DISPERSIONS

Transitional drop breakage in lean gas-agitated liquid-liquid dispersions is described and a generalized correlation for predicting drop size distribution as a function of time is presented. Experiments were performed with three ternary dispersed phase systems: linseed oil+trichloroethylene-water-air, cottonseed oil+trichloroethylene-water-air and dibenzyl ether-water-air. The results show that dispersed phase viscosity has a significant impact on the rate at which steady state drop size distributions obtain. However, initial drop size, energy dissipation rate and other physical properties of the dispersed liquid phase do not appear to have a significant impact on the rate at which steady state is reached. A similarity variable, Z = K′ t [V/Vvs] [μd/μc]0.2936, which facilitates the prediction of transient drop size distributions is identified and transitional drop size distributions are expressed as a Weibull distribution in this variable. All three dispersions behaved similarly. The derivative properties of the distribution model are consistent with erosive breakage. All results are compared with stirred tank analogues. © 1990.