PREDICTION OF VLE DATA

Abstract

This dissertation presents an investigation on the prediction of VLE data for binary, ternary and multi-component liquid mixtures. Five mixtures of binary systems namely, acetone-benzene, ethanol-water, ethanol-toluene, water-acetic acid and acetone—chloroform have been used for the calculation of VLE data. Ethanol-water and acetone-chloroform form azeotrope while water-acetic acid show non-ideality in the mixtures. So, they have been included in the investigation. The predictions have been carried out by the use of equation of state and activity coefficient models namely, Margules equation, Van Laar equation, Wilson equation, NRTL equation and UNIQUAC model for low to moderate pressure. As a result of the. comparison of data with the experimental values, UNIQUAC model has been found to predict the VLE data of ethanol-toulene and acetone-chloroform systems with least deviation. Similarly, Wilson equation also offered water-acetic acid and acetone-chloroform VLE data and Margules equation also predicted the VLE data of ethanol-toluene and ethanol-water systems with a least deviation. Binary systems of acetone-methanol and hydrogen—sulphide-n-pentane at high pressure have also been investigated. VLE data at high pressures have been predicted using Peng-Robinson and Soave-Redlich-Kwong equation of state. The predictions have been found to be in good agreement with the experimental values. This approach has also been used for the predictions of VLE data for a ternary systems- Acetylene-ethane-ethylene and also a multi-component system of n-pentane-n-butane-propane-ethane-methane. Comparison of the respective VLE data with the experimental values yielded deviation between this two to be within the acceptable range. Ill The investigation has also been extended to check the validity of each model for the binary systems considered here. This has been carried out by using the Thermodynamic equation of Gibbs-Duhem. As a result, consistent models have been identified for each system.