Extension of the PPR78 model (predictive 1978, Peng–Robinson EOS with temperature dependent kij calculated through a group contribution method) to systems containing aromatic compounds

In a previous paper [J.N. Jaubert, F. Mutelet, Fluid Phase Equilib. 224 (2004) 285–304], we started to develop a group contribution method aimed at estimating the temperature dependent binary interaction parameters (kij(T)) for the widely used Peng–Robinson equation of state (EOS). In this approach, the kij between two components i and j is a function of temperature (T) and of the pure component critical temperatures (Tci and Tcj), critical pressures (Pci, Pcj) and acentric factors (ωi, ωj). Because our model relies on the Peng–Robinson EOS as published by Peng and Robinson in 1978 and because the addition of a group contribution method to estimate the kij makes it predictive, this model was called PPR78 (predictive 1978, Peng–Robinson EOS). In our previous paper, six groups were defined: CH3, CH2, CH, C, CH4 (methane) and C2H6 (ethane). It was thus possible to estimate the kij for any mixture of saturated hydrocarbons (n-alkanes and branched alkanes), whatever the temperature. In this study, the PPR78 model is extended to systems containing aromatic compounds. To do so, two new groups were added: CHaro and Caro.