The application of the GC EOS to fluorinated refrigerant + n-alkane mixtures

MARK D. WILLIAMS-WYNN; FRANCISCO A. SÁNCHEZ; PARAMESPRI NAIDOO; SELVA PEREDA; DERESH RAMJUGERNATH

Barcelona

Congreso; 10th World Congress of Chemical Engineering; 2017

EFCE-Spain group

As a continuation of the study of the vapour-liquid equilibrium (VLE) of homologous binary systems consisting of either trifluoromethane (R-23) or hexafluoroethane (R-116) with an n-alkane, the ability of the GC EOS to describe the phase behaviour was investigated.  Normal, straight-chained alkanes with carbon numbers ranging from 2 to 11, were investigated in this study.  The vapour liquid equilibrium data for these systems have been reported by a number of different authors, within the temperature ranges of (188 to 323) K and with pressures of up to 9.1 MPa.The Group Contribution Equation of State (GC EOS) [1] is particularly useful in the prediction of the fluid properties of homologous series, such as with the n-alkane series.  It has been used to give a good description of binary mixtures of carbon dioxide with n-alkanes with carbon numbers of up to 36 [2].  With the availability of phase equilibrium data for the R-23 or R-116 + n-alkane, it was therefore of interest to determine whether the GC EOS was capable of predicting the behaviour of these similar systems.  This would enlarge the types of systems for which the GC EOS could be used to predict phase behaviour, particularly for hydrofluorocarbon-alkane systems.It was found that the GC EOS could predict the behaviour of the binary systems for the entire homologous series with the regression of the parameters against the phase equilibrium of only a select number of systems.  The GC EOS can therefore be used to obtain good predictions of the phase equilibrium of systems containing R-23 or R-116 with heavier n-alkanes with a good confidence.