RAPID

Separation of liquid mixtures, frequently by distillation, consumes large amounts of energy in the chemical and process industries. This project proposes to develop, test, and demonstrate a continuous-flow, scalable, nonthermal, nonequilibrium liquid separation for the test case of ethanol + water that uses ultrasound, and avoids the heat transfer losses and azeotropic bottleneck of distillation. The basis of the separation is straightforward. When ultrasound passes through a nominally quiescent liquid with a free surface above, droplets are produced and form a mist. Previous work in this area shows that in aqueous ethanol solutions, removal of these droplets using a carrier-gas flow provides a liquid in which ethanol is significantly enriched relative to the initial bulk solution. Successful deployment of this technology could result in significant savings in energy and capital costs for this high-volume separation, and will lay the groundwork for similar separations in a broad class of other binary (and probably multi-component) systems, including those forming azeotropes.