Calculation of mixture critical diagrams using an equation of state based on the lattice fluid theory

A modified form of the Hicks and Young algorithm was used with the Mattedi- Tavares-Castier lattice equation of state (MTC lattice EOS) to calculate cr itical points of binary mixtures that exhibit several types of critical beh avior. Several qualitative aspects of the critical curves, such as maxima a nd minima in critical pressure, and minima in critical temperature, could h e predicted using the MTC lattice EOS. These results were in agreement with experimental information available in the literature, illustrating the fle xibility of the functional form of the MTC lattice EOS. We observed however that the MTC lattice EOS failed to predict maxima in pressure for two of t he studied systems: ethane + ethanol and methane + n-hexane. We also observ ed that the agreement between the calculated and experimental critical prop erties was at most semi-quantitative in some examples. Despite these limita tions, in many ways similar to those of other EOS in common use when applie d to critical point calculations, we can conclude that the MTC lattice EOS has the ability to predict several types of critical curves of complex shap e.