Correlation of VLE data for binary mixtures of 1-alkanols and normal hexane with the Trebble-Bishnoi equation of state

Abstract

Vapour-liquid equilibrium data for six binary systems of primary alcohols (methanol-hexanol) and normal hexane were correlated with both the Trebble-Bishnoi equation of state and the Peng-Robinson EOS. Both equations yielded reasonable results for all of the systems except methanol-hexane where the prediction of liquid-liquid equilibria precluded an accurate fit of the VLE data. For the other five binary systems the average absolute deviation in vapour mole fractions for 98 data points was 0.0197 for the TB EOS and 0.0391 for the PR EOS. Bubble point pressures (60 points) and bubble point temperatures (38 points) were fit with deviations of 5.46% and 1.92 K respectively for the TB EOS while the PR EOS gave deviations of 10.82% and 2.10 K respectively. The binary systems were fit with two generalized interaction parameters for the TB EOS and with one binary-specific interaction parameter for the PR EOS. Vapour pressure and volumetric data for the primary alcohols up to 1-decanol were used to generate component dependent parameters for the TB EOS which were then generalized against molecular weight. Overall errors of 3.72% in vapour pressure were obtained for 237 data points while the PR EOS gave an average of 13.31%. Errors in liquid volumes for 110 data points were 3.15% for the TB EOS and 11.25% for the PR EOS. Vapour volume errors for 85 data points were 7.80% from the TB EOS and 6.48% from the PR EOS.