Improved models for the prediction of activity coefficients in nearly athermal mixtures 1 Part II. A theoretically-based GE-model based on the van der Waals partition function

Kontogeorgis, GM; Nikolopoulos, GI; Fredenslund, A; Tassios, DP

dc.contributor.author	Kontogeorgis, GM	en
dc.contributor.author	Nikolopoulos, GI	en
dc.contributor.author	Fredenslund, A	en
dc.contributor.author	Tassios, DP	en
dc.date.accessioned	2014-03-01T01:12:59Z
dc.date.available	2014-03-01T01:12:59Z
dc.date.issued	1997	en
dc.identifier.issn	03783812	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/12311
dc.subject	Alkane solutions	en
dc.subject	Excess properties	en
dc.subject	Free-volume	en
dc.subject	Polymer solutions	en
dc.subject	Statistical mechanics	en
dc.subject.other	Calculations	en
dc.subject.other	Degrees of freedom (mechanics)	en
dc.subject.other	Density (specific gravity)	en
dc.subject.other	Forecasting	en
dc.subject.other	Functions	en
dc.subject.other	Mathematical models	en
dc.subject.other	Mixtures	en
dc.subject.other	Paraffins	en
dc.subject.other	Phase equilibria	en
dc.subject.other	Polymers	en
dc.subject.other	Activity coefficients	en
dc.subject.other	Alkane polymers	en
dc.subject.other	Flory-Huggins formula	en
dc.subject.other	Free volume effect	en
dc.subject.other	van der Waals partition function	en
dc.subject.other	Thermodynamic properties	en
dc.title	Improved models for the prediction of activity coefficients in nearly athermal mixtures 1 Part II. A theoretically-based GE-model based on the van der Waals partition function	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/S0378-3812(96)03145-7	en
heal.identifier.secondary	http://dx.doi.org/10.1016/S0378-3812(96)03145-7	en
heal.publicationDate	1997	en
heal.abstract	This work, which is a continuation of a recent publication on the same topic (G.M. Kontogeorgis, P. Coutsikos, P. Tassios and Aa. Fredenslund, Fluid Phase Equilibria, 92 (1994) 35), presents a new theoretically-based GE-model (Chain-FV) for alkane systems. The model is based on a modified form of the generalized van der Waals partition function and attempts to account for all non-energetic effects of solutions of both short- and long-chain alkanes, including alkane polymers. Both the free-volume effects and the density-dependent rotational degrees of freedom are considered. The resulting GE-model which, despite its derivation from a partition function resembles the Flory-Huggins formula, is suitable for vapor-liquid and solid-liquid equilibrium calculations for nearly athermal polymer solutions as well as for alkane systems. We show that using plausible assumptions for the free-volume and the external-degree-of-freedom parameter, very good predictions are obtained for activity coefficients of asymmetric alkane systems at both concentration ends, for solid-liquid equilibrium calculations, as well as in extreme cases (polymer solutions, activity coefficients of heavy model alkane polymers in short-chain compounds recently available from molecular simulation studies). The predictions of the Chain-FV model are better than the Flory-Huggins and Elbro terms and equivalent to the recently proposed empirical R-UNIFAC and p-FV models. However, unlike the latter two models, the one proposed in this work offers a successful combination of simplicity and accuracy, with a solid theoretical basis.	en
heal.journalName	Fluid Phase Equilibria	en
dc.identifier.doi	10.1016/S0378-3812(96)03145-7	en
dc.identifier.volume	127	en
dc.identifier.issue	1-2	en
dc.identifier.spage	103	en
dc.identifier.epage	121	en