ANALYSIS OF ZERO-REFERENCE-PRESSURE EOS G(E) MODELS/

An analysis of EoS/G(E) models, which are based on matching the EoS-de rived expression for. the excess Gibbs free energy G(E) With that from a G(E) model at zero pressure, is presented with the focus on the mos t successful and winery used of these models, MHV2 and PSRK. It shows why zero-reference-pressure models do not reproduce exactly the G(E) m odels at zero pressure and the ensuing implications on the prediction of asymmetric systems. The development of EoS/G(E) models that reprodu ce exactly the G(E) model is discussed However, such reproducibility a t zero pressure is impossible for systems containing components with r educed temperatures higher than about 0.9. Therefore, extrapolation sc hemes that allow treatment of such systems are examined.