Representative drop sizes and drop size distributions in A/O dispersions in continuous flow stirred tank

Abstract

This work presents experimental studies of drop size distributions in aqueous in organic (A/O) dispersions produced in a continuous flow stirred tank agitated by a four-bladed top shrouded turbine with trapezoidal blades. The organic phase is a mixture of n-paraffin, tributyl phosphate (TBP) and di-2-ethyl hexyl phosphoric acid (D2EHPA), the aqueous phase is dilute phosphoric acid. Drop size measurements have been performed for different values of impeller speed, feed phase ratio and mean residence time at two locations in the tank, near the wall. Surfactant stabilization of the dispersion has been used as the drop size measuring technique. Log-normal distributions are found to fit the experimental drop size distributions. Experimental results have been used to obtain the empirical correlations for representative drop sizes — Sauter mean diameter and maximum stable diameter.