Table of Contents
Journal of Thermodynamics
Volume 2011, Article ID 251075, 11 pages
http://dx.doi.org/10.1155/2011/251075
Research Article

Vapor-Liquid Equilibrium of Carbon Dioxide + Ethanol: Experimental Measurements with Acoustic Method and Thermodynamic Modeling

1Centro de Tecnologia, Escola de Química Bloco E Sl E-201, Federal University of Rio de Janeiro, Avenida Horácio Macedo, 2030, 21941-909 Ilha do Fundão, RJ, Brazil
2Centro de Tecnologia, COPPE-PEQ-UFRJ, Avenida Horácio Macedo, 2030, Bloco G S-l G-119, 21941-909 Ilha do Fundão, RJ, Brazil
3Departamento de Engenharia Química, Universidade Estadual de Maringá, Avenida Colombo, 5790, Bloco D-90, 87020-900 Maringá, PR, Brazil

Received 25 November 2010; Revised 22 February 2011; Accepted 15 March 2011

Academic Editor: Felix Sharipov

Copyright © 2011 Ana Mehl et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Phase behavior of systems composed by supercritical carbon dioxide and ethanol is of great interest, especially in the processes involving supercritical extraction in which ethanol is used as a cosolvent. The development of an apparatus, which is able to perform the measurements of vapor-liquid equilibrium (VLE) at high pressure using a combination of the visual and the acoustic methods, was successful and was proven to be suited for determining the isothermal VLE data of this system. The acoustic method, based on the variation of the amplitude of an ultra-sound signal passing through a mixture during a phase transition, was applied to investigate the phase equilibria of the system carbon dioxide + ethanol at temperatures ranging from 298.2 K to 323.2 K and pressures from 3.0 MPa to 9.0 MPa. The VLE data were correlated with Peng-Robinson equation of state combined with two different mixing rules and the SAFT equations of state as well. The compositions calculated with the models are in good agreement with the experimental data for the isotherms evaluated.