Comparison of Mixing Technologies for the Production of Concentrated Emulsions

Abstract

The generation of surfactant stabilized water-in-oil emulsions has been studied using different mixing technologies ranging from a simple magnetic stirrer in a beaker to continuous processing with static mixers. Experiments were conducted with a diesel cut as the continuous phase, distilled water as the dispersed phase, and a mixture of three non-ionic surfactants as used in the patented formulation of Aquazole™. It is shown that water droplets in the submicron range can be obtained by means of very low energy input if the appropriate physical chemistry conditions prevail. As a result, at dispersed phase concentrations over 35%, the droplet size depends mostly on the surfactant concentration and is insensitive to the mixing technology used. When the dispersed phase concentration is further increased, stable dense packed emulsions with large particle diameter are produced and behave as gels. The physical chemistry parameters derived from the batch experiments are successfully applied to fine emulsion production using static mixers under creeping flow conditions.