A Comparative Study of Equations of State for Phase Equilibria of Associated Systems

摘要

Three notable equations of state (EOS) are extensively applied to associating mixtures including polymers. The selected EOS are the three groups; a Peng-Robinson EOS with an excess free energy based mixing rules, the hard sphere chain based SAFT model, and the lattice fluid based NLF-HB EOS. To evaluate the applicability of these EOSs, the calculated results were compared for their accuracies in predicting bubble point pressures, vapor mole fractions, and activities based on the identical but various data sets. All models were found generally less accurate in the critical region and for non-polar polymers in polar-but non-associating solvents. Cases in which a model does better or worse were identified and discussed. Also discussed were parameter characteristics and the computation time.