Vapor-Liquid Equilibrium of Ethanol + Isoamyl Alcohol At 50 and 101.3kPa

Vapor-Liquid Equilibrium of Ethanol + Isoamyl Alcohol at 50 and 101.3kPa

Fernando Córdoba¹, Jairo Duran¹, Alvaro Orjuela L¹ Iván Gil¹, Gerardo Rodríguez¹.

¹ Grupo de Procesos Químicos y Bioquímicos, Department of Chemical and Environmental Engineering, Departamento de Ingeniería Química y Ambiental

Abstract

Vapor-liquid equilibrium data for the system Ethanol + Isoamyl alcohol were measured at 50 and 101.3 kPa. A dynamic equilibrium apparatus was used for the measurements (Fischer Labodest VLE-602). Equilibrium data were fitted with UNIFAC Dortmund, NRTL and UNIQUAC models, obtaining a maximum absolute error of 1%. Herrington area test was performed using the criteria of Wisniak (1993) and Kojima et al (2004). Also, Van Ness test was used as modelling capability test for NRTL and UNIFAC Dortmund models. Good thermodynamic consistency was found with both tests. UNIFAC group contribution model was used to predict liquid phase activity coefficients of the systems at pressures under study. Experimental data are in good agreement with UNIFAC predictions. All data sets showed positive deviation from ideality.

Thermodynamic models here obtained can be applied in simulations for analysis and design in processes involving the system investigated. An example for the application of these models is the separation of Fusel Oil, a byproduct of the production of ethanol from sugar cane. Experimental and simulated data are presented in Figure 1.   

Figure 1. Experimental and simulated data with Aspen Plus using NRTL propertie package for Vapor-Liquid Equilibrium of  Ethanol + Isoamyl Alcohol: (Triangle) Experimental data at 101.3 kPa, (circle) Experimental data at 50 kPa, (dashed line) simulated data at 101.3 kPa, (continuous line) simulated data at 50 kPa.

Keywords: UNIFAC, NRTL, Consistency test, Fusel Oil.