Water-In-Oil Emulsification: A Physicochemical Study

Abstract

ABSTRACT This paper summarizes the results of a study that examined the basic mechanism by which asphaltenes, resins, and waxes stabilize water-in-oil emulsions. Experiments were conducted on the emulsification behavior of model oils that contained alkane and aromatic components and emulsifying agents. Results clearly demonstrate the importance that the physical state of an emulsifying agent has upon its ability to stabilize emulsions. It was found that, to be effective, emulsifiers, asphaltenes, resins, and waxes must be in the form of finely divided, submicron particles. In addition, it was shown that the solvency strength of an oil, which is determined by its alkane and aromatic components, controls the solubility/precipitation behavior of these emulsifiers. The chemical composition of the oil determines not only the amount and size of precipitated particles, but also the composition and wetting properties of the particles. All these factors were shown to influence emulsification. The use of a solubility model, using the Hildebrand-Scatchard equation, to predict the physicochemical conditions that favor water-in-oil emulsification, is discussed.