Experimental data and new binary interaction parameters for ethanol-water VLE at low pressures using NRTL and UNIQUAC

Marco Andrés Guevara, Fredy Alejandro Guevara, Luis Carlos Belalcázar


Separation of ethanol from many sources, mainly renewable sources, is commonly achieved by atmospheric distillation. Even so, there is new technologies for ethanol separation and purification: pressure-swing distillation, extractive distillation, adsorption with molecular sieves and vacuum membrane distillation. The design, rating and optimization of these process technologies requires a reliable and universal thermodynamic modeling approach capable of represents the ethanol-water system properties, and in particular the vapor-liquid equilibrium (VLE) near the azeotropic point. This study resume experimental data of VLE for ethanol-water system at vacuum pressures (13.15-101.32 kPa) and its corresponding thermodynamic consistency test results using the Redlich-Kister method. The parameters and constants for the detailed thermodynamic modeling of the ethanol-water system using polar fluid Soave-Redlich-Kwong equation of state (polar-SRK) are resumed, as well as the standard binary interaction parameters for NRTL and UNIQUAC excess Gibbs energy models commonly used for the simulations involved in the chemical process engineering activities. This study contains the regression of new binary interaction parameters in a temperature dependent form compatible with the most process simulation software, for NRTL and UNIQUAC, and its validation using experimental data for azeotropic points at different low pressures with errors of less than 1% for temperature and ethanol molar fraction in vapor phase estimation. The new parameters were tested using isobaric experimental data for VLE at 3 under-atmospheric pressures obtaining correlation coefficient (R2) values of about 1. The calculations were performed using python 3.4® codes developed and supplied by S&SE and Aspen properties® V8.6 provided by the Universidad Nacional de Colombia.


ethanol-water; experimental data; vapor-liquid equilibrium; Azeotropic point; NRTL;UNIQUAC; binary parameters.

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J. Baeyens, Q. Kang, L. Appels, R. Dewil, Y. Lv, and T. Tan, “Challenges and opportunities in improving the production of bio-ethanol,” Prog. Energy Combust. Sci., vol. 47, pp. 60–88, 2015.

A. Gupta and J. P. Verma, “Sustainable bio-ethanol production from agro-residues: A review,” Renew. Sustain. Energy Rev., vol. 41, pp. 550–567, 2015.

M. Petitfrere and D. Vladimir, “Multiphase equilibrium calculations using a reduction method,” Fluid Phase Equilib., vol. 401, pp. 110–126, 2015.

A. F. Cristino, S. Rosa, P. Morgado, A. Galindo, E. J. M. Filipe, A. M. F. Palavra, and C. A. Nieto de Castro, “High-temperature vapour-liquid equilibrium for the water-alcohol systems and modeling with SAFT-VR: 1. Water-ethanol,” Fluid Phase Equilib., vol. 341, pp. 48–53, 2013.

E. C. Voutsas, C. Pamouktsis, D. Argyris, and G. D. Pappa, “Measurements and thermodynamic modeling of the ethanol-water system with emphasis to the azeotropic region,” Fluid Phase Equilib., vol. 308, no. 1–2, pp. 135–141, 2011.

A. Farajnezhad, O. A. Afshar, M. A. Khansary, S. Shirazian, and M. Ghadiri, “Correlation of interaction parameters in Wilson, NRTL and UNIQUAC models using theoretical methods,” Fluid Phase Equilib., vol. 417, pp. 181–186, 2016.

L. Axelsson, M. Franzén, M. Ostwald, G. Berndes, G. Lakshmi, and N. H. Ravindranath, “Perspective: Jatropha cultivation in southern India: Assessing farmers’ experiences,” Biofuels, Bioprod. Biorefining, vol. 6, no. 3, pp. 246–256, 2012.

Y. Dadmohammadi, S. Gebreyohannes, B. J. Neely, and K. A. M. Gasem, “Multicomponent phase behavior predictions using QSPR-generalized NRTL and UNIQUAC models,” Fluid Phase Equilib., vol. 409, pp. 318–326, 2016.

J. A. Sandarusi, A. J. Kidnay, and V. F. Yesavage, “Compilation of parameters for a polar fluid Soave-Redlich-Kwong equation of state,” Ind. Eng. Chem. Process Des. Dev., vol. 25, no. 4, pp. 957–963, 1986.

J. M. Smith, H. Van Ness, and M. M. Abbott, Introduction to Chemical Engineering Thermodynamics, 7th ed. 2005.

M. Llano-Restrepo and J. I. Carrero-Mantilla, “Futility or usefulness of common implementations of the area and slope consistency tests for partial molar properties in binary mixtures,” Fluid Phase Equilib., vol. 398, pp. 72–79, 2015.

B. Daniel, M. Peters, D. Glasser, and D. Hildebrandt, Understanding Distillation Using Column Profile Maps, 1st ed. 2013.

Dormund-Data-Bank, “Dortmund Data Bank,” 2016. [Online]. Available: http://www.ddbst.com/ddb.html.

Chemicals Enigeer´s Guide, “Chemicals Enigeer´s Guide,” 2016. [Online]. Available: http://cheguide.com/. [Accessed: 01-Jun-2016].


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