Drop size distribution and Sauter-mean Drop diameters have been measured in a pilot scale Hanson mixer-settler extraction column for two different liquid-liquid systems.The experiments were carried out for both mass transfer directions. The effects of agitation speed and dispersed phase and continuous phase flow rates have been investigated under a variety of operating conditions. Mean Drop diameter axial profiles show a strong nonuniformity, while Drop size distribution does not change significantly with the column height. Sauter mean diameter and Drop size distribution are strongly affected by agitation speed and interfacial tension. Significant, but weaker are the effects of continuous phase and dispersed phase flow rates. An empirical correlation for mean Drop size as a function of Weber number, dispersed phase holdup, and viscosities ratio is suggested. In a further correlation, the dispersed phase holdup is replaced by flow rates which will certainly be known in a practical case.

A population balance model expressing both Drop breakage and coalescence was developed for poly(vinyl chloride) microsuspension process with the measured Drop size distributions (0. 1–, 1 µ, m) and volume-weighted mean diameter (0. 18–, 0. 22 µ, m) in a pilot scale double-stage high-pressure homogenizer. The prediction of the measured Drop size distributions was satisfactory in terms of incorporating both breakage rate functions due to turbulent inertial and viscous forces with the dominance of breakage rate for inertial forces. However, a reduction in the pressure and the number of passes, and a rise in the dispersed phase volume fraction and premix size distribution resulted in enhancing the anticipated Drop size distribution (D10, D90, and D90/D10). Additionally, as the emulsifier concentration improved, the distribution (D90/D10) increased due to the further decrease in mean D10 Drop size than D90, despite the low emulsifier content. The breakage rate caused by viscous forces at the lowest concentration (CsCs=5 mmol/L) enhanced the predicted distribution (D90 and D90/D10). Due to the important contribution of viscous forces at larger dispersed phase volume fractions (φ, φ, =0. 622), especially when raising the number of passes, the estimated Sauter mean diameter declined and the distribution was further augmented, despite no increase in the mean D10 Drop size. At the same time, the anticipated Sauter mean diameter improved at lower fractions (φ, φ, =0. 443). The stable Droplets with unimodal size distribution (D90/D10 , = , 2. 8) were achieved at above one recycling pass and 13. 5 MPa under second-valve pressure equal to 3 MPa with the minimum effect of changes in dispersed phase volume fraction, emulsifier concentration, and suspension premix distribution.

Sauter mean Drop sizes have been measured in a pulsed packed extraction column for two liquid systems with and without mass transfer conditions. The effects of pulsation intensity, phase flow rates, and interfacial tension on Drop size have been investigated under a variety of operating conditions. The Drop size is influenced mainly by pulsation intensity and interfacial tension. Significant, but weaker, are the effects of continuous and dispersed phase flow rates. A precise correlation is proposed for predicting mean Drop size in terms of operating variables, physical properties of the liquid systems and mass transfer direction. Good agreement between prediction and experiments is found for all operating conditions that were investigated.

Graphical size distribution is widely used in different fields of science and studies related to powders, Droplets, bubbles, and pores. However, in some condition it may also be necessary to express the size distribution quantitatively. In spite of there being several suggested ways to quantify size distribution in the literature, some of these approaches are not applicable for many methods and the rest have other drawbacks. In this study, first, some quantitative size distribution methods (such as the polydispersity index) and their defects are concisely discussed. SPAN seems to be the most generally appropriate method, its parameters are determined from cumulative size distribution data. Nevertheless, some specific results imply that there are still some drawbacks in this method. Next, a new quantitative description of size distribution is presented which is applicable to many different techniques. In this method the characterization value is limited to 0 and 1, where 0 is related to completely polydispersed size distribution and 1 denotes the completely monodispersed size distribution.