2020/10/18 by Ulrich K. Deiters, Ian H. Bell · 1 citation
Engineering · Chemical Engineering · Physics and Astronomy · #Phase Equilibria and Thermodynamics #Thermodynamic properties of mixtures #Advanced Thermodynamics and Statistical Mechanics
paper · pdf · doi:10.1007/s10765-020-02743-3
openalex publication_date 2020/10/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
When applied to asymmetric binary mixtures (e.g., methane + pentane or heavier alkanes, hydrogen-containing mixtures), the GERG equation of state (GERG-2004 or GERG-2008) predicts critical curves with physically unreasonable temperature maxima above the critical temperature of the heavier component. These maxima are associated with physically impossible vapor-liquid equilibria. The phenomenon is probably caused by corrections for critical anomalies that were built into the empirical pure-fluid equations of state forming the foundation of the GERG model. These corrections ensure that the model represents thermodynamic data of pure fluids quite well even close to their critical points. For mixtures, however, the corrections can cause artifacts.