Effect of pH and Concentrated Salt on the Droplet Size and Mass Transfer Coefficient in a Stirred Liquid-Liquid Reactor

Abstract

This work addressed liquid-liquid mass transfer for actual industrial conditions of high pH with coexisting salt. The Sauter mean diameter was determined from the direct measurement of a chlorobenzene droplet size using a borescope system. At a high NaOH concentration, the droplet size decreased significantly due to the reduced density difference between two phases, and it further decreased when NaOH and NaCl coexisted. A Sauter mean diameter correlation with a density difference term was proposed, and it successfully predicted the experimental results. To determine the mass transfer coefficient, the solubility and the concentration gradient of chlorobenzene in the aqueous phase were measured under various conditions. As the NaOH and NaCl concentration increased, the solubility of chlorobenzene and the rate of change of chlorobenzene concentration in the aqueous phase both decreased, but the decrease in solubility was more pronounced. Thus, the mass transfer coefficient increased with the NaOH and NaCl concentration.