Phase equilibria in the system nitrogen-ethane and their prediction using cubic equations of state with different types of mixing rules

The system nitrogen-ethane is of fundamental importance for the examination of nitrogen-alkane systems that exhibit miscibility gaps. The aim of this work is to compare the widely used SRK and PR cubic equation of state with different types of mixing rules with respect to their ability to represent the phase behaviour of this system. We investigated the performance of the van der Waals mixing rule, two composition depending mixing rules and some G(E)-mixing rules in combination with the NRTL and UNIQUAC model. The binary interaction parameters were obtained by fitting only experimental VLE data and then used to test the capability of the different mixing rules to predict the VLLE and to describe the saturation densities. New experimental results for the VLE below 140 K including densities supplement available data sets needed to validate the correlation results. (C) 2004 Elsevier B.V. All rights reserved.