Emulsion and Soft Colloid Transport in Porous Media and Confined Systems

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Emulsion droplets are examples of soft colloids. Oil-water emulsions are commonly found in produced water in oil field applications. These emulsions pose numerous challenges in treatment of produced water, where one attempts to destabilize and separate the oil and water into two phases. Conversely, emulsions and soft colloids are used in several process engineering applications where they need to remain stable even under the influence of shear or other destabilizing forces. Our proposed research focuses on the flow of such emulsions or deformable colloids in highly constricted channels or pores under the influence of electric field and/or pressure. The droplets can deform and break, or coalesce under the influence of shear and electrical forces during such flows. Furthermore, the walls of the constricted channels can impose forces on these emulsion droplets. The short-term objectives of the proposed research are to develop mechanistic understanding of the various electrical, fluid dynamic, and colloidal effects influencing the flow, deformation, and stability of emulsion droplets and deformable colloids. The theoretical modeling studies proposed here will build on our past experience in modeling colloid transport, thin film drainage, and droplet deformation under electrical forcing. These models will employ the governing equations of fluid flow, electric fields, and charged species distribution to determine the mobility of the droplets or soft particles. Subsequently, these models will be incorporated into a macroscopic colloid transport model to predict the macroscopic transport behavior of the emulsion or soft colloidal dispersion through a packed bed of collectors. The various theoretical models will be validated by comparing their results against suitably designed microfluidic and column chromatography experiments. The research outcomes are expected to provide a fundamental mechanistic understanding of the pertinent modes of emulsion transport in porous media, and will help develop more efficient techniques for filtration, de-emulsification, flotation, separation, and ultimately, produced water treatment. Nine graduate students will be trained through this program.