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

Abstract

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 critical points of binary mixtures that exhibit several types of critical behavior. Several qualitative aspects of the critical curves, such as maxima and minima in critical pressure, and minima in critical temperature, could be predicted using the MTC lattice EOS. These results were in agreement with experimental information available in the literature, illustrating the flexibility 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 the studied systems: ethane + ethanol and methane + n-hexane. We also observed that the agreement between the calculated and experimental critical properties was at most semi-quantitative in some examples. Despite these limitations, in many ways similar to those of other EOS in common use when applied to critical point calculations, we can conclude that the MTC lattice EOS has the ability to predict several types of critical curves of complex shape

Behavior of the Thermodynamic Properties of Binary Mixtures near the Critical Azeotrope

“…For the formulation of any thermodynamic surface for binary mixtures [13][14][15] we need the analytical relations of the critical parameters as a function of the concentration and the reason we present this work is to make researcher aware of the critical point azeotropy misunderstanding. Therefore, whenever there is a need to formulate a descriptive global equation of state for azeotropic binary mixtures we need to give a special attention of this special point.…”

Liquid Phase Density, Sound Speed, and Vapor Pressure of Linear Alkanes Using the Mattedi–Tavares–Castier Equation of State

“…Therefore, among the properties cited hitherto, only calorimetric properties are not used, mainly because of our previous results . Therefore, vapor pressure, density, and speed of sound are the focus of this work, which assesses the performance of the MTC EOS ,− in their calculation for all linear alkanes in the range C2–C20, after a prescreening of parameter fitting strategies based on n -hexane. These results are compared to those from the literature for the PC-SAFT EOS, which has been recently claimed by the authors to be a good model for the same properties and compounds considered in this paper.…”