(161g) Phase Inversion of a Solid-Stabilized Emulsion: Effect of Particle Concentration

Phase inversion of solid stabilized emulsion could be a potential workaround for the commonly encountered problems in the desalting of crude oil by making water the continuous phase during the processing. In the present work, the effect of particle concentration on the catastrophic phase inversion point was investigated. The phase inversion was systematically triggered by the continuous addition of dispersed phase. During phase inversion, we focused on tracking the droplet morphology evolution by a Particle Vision Microscope (Mettler Teledo), which proved to be a powerful tool to monitor the instable process. The phase inversion was found to occur in a regime where the particles are insufficient to fully cover the oil-water interface. A linear relationship between the particle concentration and the phase inversion point was obtained. Our findings highlighted the fact that the phase inversion always takes place above a critical value expressed as the number of particle per surface area. This always occurred, regardless of the particle concentration. The systematic observation has been explained by relating the particle coverage to the coalescence rate of the system. It has been compared to pure transient coalescence experiments using sudden reduction of impeller speed, without particles.