A Modified van der Waals Mixture Theory for Associating Fluids: Application to Ternary Aqueous Mixtures

Document Type : Research Note

Authors

1 Chemical Engineering, Department, Faculty of Engineering, University of Isfahan, Isfahan, I.R. IRAN

2 Chemical Engineering Department, Amirkabir University of Technology, Tehran, I.R. IRAN

3 Chemical Engineering Department, Faculty of Engineering, University of Isfahan, Isfahan, I.R. IRAN

Abstract

In this study a simple and general chemical association theory is introduced. The concept of infinite equilibrium model is re-examined and true mole fractions of associated species are calculated. The theory is applied to derive the distribution function of associated species. As a severe test the application of presented theory to the van der Waals mixture model is introduced in order to perform Vapor-Liquid Equilibrium (VLE) calculations of aqueous ternary mixtures. The calculations are shown to be consistently improving the prediction over the non-associating case. Also, well known empirical models of NRTL and UNIQUAC are applied on the studied systems and their results are compared with proposed model.  

Keywords

Main Subjects


[1] Prausnitz J.M., Lichtenthaler R.N., Gomes de Azevedo E., "Molecular Thermodynamics of Fluid-Phase Equilibrium", 3rd Ed., Prentice Hall International:New York, (1999).
[2] Muller E.A., Gubbins K.E., Molecular-Based Equations of State for Associating Fluids: A Review of SAFT and Related Approaches, Ind. Eng. Chem. Res., 40, p. 2193 (2001).
[3] Asprion N., Hasse H., Maurer, G., Thermodynamic and IR Spectroscopic Studies of Solutions with Simultaneous Association and Solvation, Fluid Phase Equilibria, 205, p. 195 (2003).
[4] Nose A., Hojo M., Hydrogen Bonding of Water-Ethanol in Alcoholic Beverages, Bioscience and Bioengineering, 102, p. 269 (2006)
[5] Nikolic A., Jovic B., Csanady S., Petrovic S., N–HO Hydrogen Bonding: FT IR, NIR and H-NMR Study of N-Methylpropionamide-Cyclic Ether Systems, J. Molecular Structure, 834-836, p. 249 (2007).
[6] Wenzel H., Krop E., Phase equilibrium by Equation of State: a Short-Cut Method Allowing for Association, Fluid Phase Equilibria, 59, p. 147 (1990).
[7] Aghamiri S.F., Mansoori G.A., Modarress H., A Genralized Chemical Associating Theory of Mixtures, Z. Physik. Chem. Bd., 205, p. 211 (1998).
[8] Aghamiri S.F., Modarress H., Mansoori G.A., A New Theoretical Approach to the Hydrogen Bonded Fluids Based on the Conformal Solution Theory, J. phys. chem. B, 105, p. 2820 (2001).
[9] Mohsen-Nia M., Modarress H., Association Equation of State (AEOS) Based on Aggregate Formation for Pure Substance, Chemical Physics, 336, p. 22 (2007).
[10] Kudelkova L., Lovland J., Vonka P., Crossover EOS Versus Classical EOS for Pure Fluids, Fluid Phase Equilibria, 218, p. 103 (2004).
[11] Perakis C., Voutsas E., Magoulas K., Tassios D., Thermodynamic Modeling of the Vapor-Liquid Equilibrium of the Water/Ethanol/CO2 System, Fluid Phase Equilibria, 243, p. 142 (2006).
[12] Vafaie-Sefti M., Mousavi-DehghaniS.A., Application of Association Theory to the Prediction of Asphaltene Deposition: Deposition Due to Natural Depletion and Miscible Gas Injection Processes in Petroleum Reservoirs, Fluid Phase Equilibria, 247, p. 182 (2006).
[13] Breitholz A., Yoo K., Lim J.S., Lee Ch.S., Kang J.W., Liquid-Liquid Equilibrium Correlations Using Lattice Fluid Equation of State with Hydrogen Bonding, Journal of Industrial and Engineering Chemistry, 14 (2), p. 219 (2008).
[14] Perfetti E., Thiery R., Dubessy J., Equation of State Taking into Account Dipolar Interactions and Association by Hydrogen Bonding. I: Application to Pure Water and Hydrogen Sulfide, Chemical Geology, 251 (1-4), p. 58 (2008).
[15] Nickmand Z., Aghamiri S.F., A New Modified van Laar Model for Associating Mixtures, Journal of  Dispersion  Science and Technology, 31 (12), p. 1638 (2010).
[16] Nickmand Z., Aghamiri S.F., A New Association Term for SAFT Equation of State, Journal of Dispersion Science and Technology, 31 (11), p. 1591 (2010).
[17] Anderko A., Phase Equilibria in Aqueous Systems from an Equation of State Based on the Chemical Approach, Fluid Phase Equilibria, 65, p. 89 (1991).
[18] Touba H., Mansoori G.A., Equations of Sstate for Associating Fluids (Based on the Analytic Chain Association Theory), Fluid Phase Equilibria, 119, p. 51 (1996).
[19] Hill, T.L., "An Introduction to Statistical Thermodynamics",Dover:New York, (1986).
[20] Elliott, J.R. and Lira, C. T., "Introductory Chemical Engineering Thermodynamics", Prentice Hall, UpperSaddleRiver, N. J., (1999).
[21] Walas, S.M., "Phase Equilibria in Chemical Engineering", Butterworth: Boston, (1985).
[22] Gmehling J., Onken U., Arlt W., "Vapor-Liquid Equilibrium Data Collection, Aqueuse Organic Systems, Chemistery Data Series", Vol. 1, Part 1a, Behrens, D. and Eckermann, R., Ed., DECHEMA: Frankfurt (1981).