Resumen de Experimental data and new binary interaction parameters for ethanol-water VLE at low pressures using NRTL and UNIQUAC
Marco Andrés Guevara Luna, 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.
