Semi-batch and continuous production of Pickering emulsion via direct contact steam condensation

Abstract

We propose a versatile strategy for the production of highly stable water in oil Pickering emulsion by direct contact condensation of steam. In contrast to conventional methods that use mechanical energy for creating drops, the condensation of steam brought in contact with a non-aqueous colloidal dispersion is exploited to produce Pickering emulsions in two modes of operation, namely, semi-batch and continuous. As steam that comes in contact with oil condenses into water drops, the particles adsorb to the interface and thus arrest drop–drop coalescence. The adsorption of particles on the drop's surface imparts kinetic stability to the emulsions. The dependence of size of the emulsions as a function of parameters such as steam temperature, flow rate, particle type and particle concentration is investigated. We show that the tailoring of these parameters allows a precise control over droplet size distribution. The flexibility of continuous mode of operation makes it a potential technique for large scale production of emulsions suited for many applications.