Prediction of the critical properties of n-alkanes and their mixtures with two versions of SAFT equation of state

Abstract

Two versions of statistical associating fluid theory (SAFT) equation of state (EoS), namely modified SAFT-BACK and original SAFT, were used to calculate the critical temperatures and pressures of 10 n-alkanes (from $$c_{1}$$ to $$c_{10}$$ ). The obtained results were compared with the available experimental data to assess the predictive power of these EoSs in the critical region. The absolute average percentage deviation (AAD %) of the results obtained from the modified SAFT-BACK model indicated that this EoS had a good performance in the prediction of the critical points of the n-alkanes, but the deviation resulting from the original SAFT EoS reflected the limitations of the latter EoS in representing the critical region. Moreover, the critical temperatures for binary mixtures of n-alkane were calculated using both the original SAFT and the modified SAFT-BACK models and the results were compared with the data predicted by the correlation relations. The modified SAFT-BACK model showed a very good performance, while the original SAFT model did not yield an appropriate prediction of the critical temperatures of n-alkane binary mixtures.