A new analytical formulation for the generalized corresponding states model for thermodynamic and surface properties in pure fluids

• Published in: Chemical engineering science 2006-08, Vol.61 (15), p.5107-5113
• Main Authors: Kiselev, S.B., Ely, J.F.
• Format: Article
• Language: English
• Subjects: Applied sciences; Chemical engineering; Chemical thermodynamics; Chemistry; Exact sciences and technology; General and physical chemistry; General. Theory; Interface; Phase equilibria; State equation; Supercritical fluid; Theory of liquids; Thermodynamic properties
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/j.ces.2006.03.044

In a previous study [Kiselev, S.B., Ely, J.F., 2003. Generalized corresponding states model for bulk and interfacial properties of pure fluids and fluid mixtures. Journal of Chemical Physics 119(16), 8645–8662] we developed a formulation of the generalized corresponding states (GCS) model which incorporated critical region non-analytic behavior via a parametric crossover function. The parametric variable in that model was obtained from the crossover modification of the sine model originally proposed by Fisher et al. [1999. Trigonometric models for scaling behavior near criticality. Physical Review B 59(22), 14533–14545]. In this work we have developed a new version of the GCS model that incorporates an analytical sine (ANS) model solution which greatly simplifies the application of the resulting equation of state (EOS). Similar to the original GCS/CRS model, the new GCS/ANS model contains the critical point parameters and acentric factor as input and yields a very accurate description of the PVT- and VLE-surfaces of one-component fluids in a wide range of thermodynamic states, including the nearest vicinity of the critical point. The GCS/ANS model reproduces the saturated pressure and liquid density data with an average absolute deviation (AAD) of about 1% and the vapor density with AAD of about 2–3%. In the one phase region for ρ ⩽ 2 ρ c the model reproduces the PVT data with an AAD less then 2% and for liquid densities where ρ ⩾ 2 ρ c with an AAD of about 1–2%. In combination with the density functional theory (DFT), the GCS/ANS–DFT model is also capable of reproducing the surface tension of one-component fluids (polar and non-polar) with high accuracy.