Prediction of aliphatic and aromatic oil-water interfacial tension at temperatures 100 degrees C using COSMO-RS

摘要

As a contribution to the 9th Industrial Fluid Property Simulation Challenge on predicting interfacial tension between water and a set of non-polar oils at temperatures up to 170 degrees C we have used our first principles based model, which is based on density functional theory and uses COSMO-RS implicit solvent model thermodynamics. Our calculations predict that the oil-water interfacial tension starts to drop significantly for alkanes at temperatures above similar to 100 degrees C, and the oil-water interfacial tension drops significantly with increased temperature already above similar to 25 degrees C for aromatic oils. In the range 110-170 degrees C, the interfacial tension drops almost linearly with temperature at a rate of about -0.082 mN/m/K for dodecane and -0.147 mNimiK for toluene. Our method predicts that for any mix of dodecane and toluene, a linear interpolation of the interfacial tension with respect to the composition is a good approximation. The agreement of our predictions with the experimental data was overall satisfying, apart from a significant difference in the temperature dependence of the dodecane-water interfacial tension. We provide results derived from other experimental measurements suggesting that the large decrease measured by the challenge organizers may be erroneous. (C) 2017 Elsevier B.V. All rights reserved.