ON THE PREDICTION OF THE GAS-LIQUID CRITICAL LOCUS WITH CUBIC EQUATIONS OF STATE

Seven cubic equations of state have been compared with regard to their applicability to predict the gas-liquid critical state using parameters taken from the vapour-liquid equilibrium data fit. The nitrogen + methane and methane + n-decane systems have been chosen for the study. For the former, the description of the critical state is satisfactory to compare the models and the critical loci show a slight dependence on the model. For the latter, the predicted critical loci strongly depend on the model used. On that example a great flexibility of cubic equations of state in modelling of critical state is proved.