Critical points of hydrocarbon mixtures with the Peng-Robinson, SAFT, and PC-SAFT equations of state

Marcelo F. Alfradique, Marcelo Castier

Research output: Contribution to journalArticle

24 Citations (Scopus)


The phase behavior of fluids at high pressures can be rather complex, even for mixtures of relatively simple molecules, such as hydrocarbons. In this work, we use the Hicks and Young algorithm to calculate mixture critical points, comparing five modeling options: Peng-Robinson EOS: (1) original and (2) with parameters fitted from molar volume and vapor pressure data; (3) SAFT EOS; and PC-SAFT EOS: (4) original and (5) with refitted parameters to match pure component critical data. Calculations were carried out for binary hydrocarbon mixtures and 29 multicomponent mixtures. The SAFT EOS provided the worst representation of the systems tested and, interestingly, the conventional cubic EOS provided, in general, the best representation.

Original languageEnglish
Pages (from-to)78-101
Number of pages24
JournalFluid Phase Equilibria
Issue number1
Publication statusPublished - 15 Aug 2007
Externally publishedYes



  • Critical points
  • Equations of state
  • Hydrocarbons
  • Peng-Robinson
  • SAFT

ASJC Scopus subject areas

  • Fluid Flow and Transfer Processes
  • Physical and Theoretical Chemistry

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