ESTIMATION OF COALESCENCE AND BREAKAGE RATE CONSTANTS KUHNI COLUMN

A simplified population balance model is presented to describe the hyd rodynamics of the dispersed phase within a Kuhni column. This model is fitted to experimental axial drop size distribution profiles by the o ptimization of expressions for the breakage and coalescence rate coeff icients. Thus, over the experimental range of study correlations for t hese rate coefficients are developed respectively as breakage, Br-ij = 3.0N(u(ij)/H-s) exp[(-1.8 x 10(-4)DF(phi))/(N(2)d(i)(5/3))], and coal escence (h lambda)(ij) = 0.640(u(ij)/H-s)phi(j)(-1.3)v(i)(0.56). These expressions indicate that the breakage and coalescence rate coefficie nts are much less dependent upon rotor speed than suggested by correla tions in the literature for turbulent stirred tanks. In contrast, as s uggested by Gourdon et al. (Chem. Eng. J. 1991, 46, 137), these coeffi cients are correlated with the drop residence time, which in turn is d etermined by the individual droplet velocities.