A Perturbed-Chain SAFT Equation of State Applied to Mixtures of Short- and Long-Chain n‑Alkanes

• Main Author: Nasrifar, Khashayar
• Format: Article
• Published: American Chemical Society Publication 2013
• Subjects: TP Chemical technology
• Online Access: http://eprints.utp.edu.my/9838/1/2013-PCSAFT-N.pdf; http://eprints.utp.edu.my/9838/

ABSTRACT: A simplified hard-chain dimer theory is employed with perturbed-chain statistical associating fluid theory (PCSAFT) in calculating the vapor pressures and saturated liquid volumes of pure n-alkanes from methane to n-eicosane. Compared to the original PC-SAFT, the developed model is in better agreement with the experimental vapor pressures and saturated liquid volumes of n-alkanes along the vapor−liquid coexistence curve and the critical properties from n-butane toward longer n-alkanes. Predicting the vapor−liquid equilibria (VLE) of binary mixtures containing methane and a long-chain n-alkane, the new model describes the mixtures more accurately than PC-SAFT. With no binary interaction parameter, the model adequately describes the experimental VLE data, in particular, near the critical points. In the prediction of the VLE of mixtures containing ethane, propane, n-hexane, and a long-chain n-alkane, the differences between the two models become less appreciable.