Solids-stabilized oil-in-water emulsions: Scavenging of emulsion droplets by fresh oil addition

Abstract

A novel method for breaking up solids-stabilized oil-in-water emulsions was investigated on the basis of a simple concept. Kaolinite clay particles were used as the stabilizing solids, whose wettability (contact angle) was varied by controlling the amount of asphaltene adsorption on the clay particles. A light mineral oil (Bayol-35) was used as the dispersed phase. It was found that the contact angle of the treated clay particles, measured across the water phase, increased with increasing asphaltene concentration. The prepared emulsion (oil) droplet size increased significantly with increasing clay contact angle. The demulsification process was conducted in a 1 1 beaker equipped with baffles, under stirring action. The method of scavenging emulsion oil droplets by the use of large fresh oil droplets proved to be effective. The demulsification was enhanced with increasing amount of fresh oil added. The demulsification was more effective for emulsions stabilized with clays having larger contact angles. An increase in the rotational speed of the stirrer also enhanced the demulsification process.