High pressure phase equilibrium measurements of long chain alcohols in supercritical ethane

Abstract

High pressure phase equilibrium measurements of long chain 1-alcohols (1-decanol through 1-docosanol) in supercritical ethane and their prediction are presented. The data were measured in a high pressure view cell above the melting points of these alcohols, i.e. between 308 and 356 K, and with 1-alcohol mass fractions ranging from 0.0173 to 0.648. The results show a linear relationship between the phase transition pressure and the system temperature. The phase transition pressure increases with increasing molecular mass of 1-alcohol at constant temperature and composition. Furthermore, a linear relationship exists between the phase transition pressure and the number of carbon atoms of the 1-alcohol, making it easy to predict phase transition by simple interpolation within the experimental boundaries. Additionally, the state-of-the-art sPC-SAFT EOS model, as now typically included in process simulators, is unable to predict the phase equilibria, although it tends to give better results than the classic Peng Robinson EOS.