Data driven temperature dependence of EOS parameters

A. Deák, S. Kemény, I. Farkas

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1 Citation (Scopus)


Using three kinds of experimental data (pc, Vc and Tc at the critical state or ps, Vsv and VsL at different temperatures for saturation data) three parameters of the EOS may be directly determined and the temperature dependence of the parameters may be established from thermodynamic conditions of vapour - liquid critical point or vapour - liquid phase equilibria respectively. The principle was demonstrated on the BACK EOS. Examples of argon and n-alkanes were used to demonstrate the idea. It was found, that there are two parameter sets of the BACK equation that satisfy the critical or saturation conditions for certain pure compounds. The BACK equation is able to reproduce experimental Zc values for compounds above Zc = 0.2764 (that is, for argon, methane, ethane), but it is improper for higher alkanes. In case of n-alkanes we found that there is no simple function for T dependence of BACK parameters. Parameter values obtained in the way demonstrated may be useful to give initial values for parameter estimation from experimental (e.g., VLE) data.

Original languageEnglish
Pages (from-to)97-105
Number of pages9
JournalFluid Phase Equilibria
Issue number1-2
Publication statusPublished - Dec 1 1997



  • Critical state
  • Equation of state
  • Vapour - liquid equilibria

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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