Gn. Escobedo-alvarado et al., Modeling of solid-supercritical fluid phase equilibria with a cubic equation of state-G(ex) model, J SUPERCR F, 21(2), 2001, pp. 123-134
Equations of state (EOS) are an important tool for the correlation and pred
iction of thermodynamic properties and phase behavior of pure substances an
d mixtures. Therefore EOS are widely used in design, simulation and optimiz
ation of chemical processes. In particular, cubic EOS are routinely used in
the chemical and petrochemical industries to calculate phase equilibria an
d thermophysical properties. This approach proves to be simple and accurate
for engineering calculations. However, when these equations are used with
the classical van der Waals mixing rules they do not perform well for highl
y polar, asymmetric and/or associating mixtures. Consequently, numerous mix
ing rules have been proposed to extend the capabilities of cubic EOS. Recen
tly, several mixing rules have been developed that contain excess Gibbs ene
rgy (G(ex)) models. The Wong-Sandler mixing rule belongs to this group, and
has been successfully used to describe the phase behavior of mixtures that
involve both polar and associating fluids. Here we consider the applicatio
n of this mixing rule to solid-supercritical fluid phase equilibria as solv
ent extraction with supercritical or near-critical fluids has been proposed
as an alternative to conventional separation processes. While these system
s generally involve constituents that are of very different molecular natur
e (i.e. asymmetric mixtures), the EOS model considered here successfully de
scribed binary and ternary solid-supercritical fluid mixtures. (C) 2001 Els
evier Science B.V. All rights reserved.