DROP-SIZE DISTRIBUTION AND AVERAGE DROP SIZE IN A WIRZ EXTRACTION COLUMN

Drop-size distributions and voliume-surface average diameters have bee n measured in a Wirz-II agitated extraction column for six different l iquid-liquid systems as a function of phase flow rates and intensity o f agitation at three positions along the column axis. Experimental dro p-size distributions were compared with three two-parameter theoretica l distribution functions, namely, the log-normal, Gamma, and Weibull. The Gamma function was found to be the most suitable. An empirical cor relation for a dimensionless width of the drop-size distribution is pr esented in terms of the rate of agitation and interfacial tension. The Sauter mean diameter was found to depend on the speed of agitation, p hysical properties of liquid systems, and phase flow rates. It could b e correlated using an additive model involving the ratio of buoyancy t o interfacial forces at low agitation, and a turbulent breakup mechani sm at high agitation, the effect of flow rates being expressed in term s of the dispersed-phase holdup.