| Summary: | 碩士 === 靜宜大學 === 應用化學研究所 === 98 === The vapor-liquid equilibria (VLE) were then measured by mixing the fuel oxygenates that might be used as an octane number enhancer with one of the gasoline components. In the experiments, two oxygenates used were tetrahydropyran and 2-propanol and the gasoline component was 2,2,4-trimethylpentane. The vapor-liquid equilibria were measured at 101.3 kPa for three binary systems (2-propanol + tetrahydropyran , 2-propanol + 2,2,4-trimethylpentane, and tetrahydropyran + 2,2,4-trimethylpentane) and one ternary system(2-propanol + tetrahydropyran + 2,2,4-trimethylpentan).
Both the equation with fugacity coefficients and the equation based on the modified Raoult’s law were used to calculate the activity coefficients of liquid mixtures in the experimental systems. The vapor-phase fugacity coefficients were calculated using the Soave- Relich-Kwong equation of state. The results from the analysis of the experimental VLE data found a minimum boiling azeotrope on 2-propanol + tetrahydropyran and 2-propanol + 2,2,4- trimethylpentane binary systems but not on the ternary system. In the thermodynamic consistency, the binary systems were tested using Kojimas method and the direct test method of Van Ness, and the ternary data were tested using the McDermott-Ellis method modified by Wisniak and Tamir.
The liquid activity coefficients in binary systems were correlated using the Margules, Wilson, NRTL and UNIQUAC models. The models with the best-fitted parameters were used to predict the ternary VLE data. The excess molar Gibbs free energy and the deviation the equilibrium boiling temperature of binary systems were correlated using the Redlich-Kister equation; for the ternary system, the excess molar Gibbs free energy and the average deviation in the boiling temperature were correlated with the equations of Jasinski and Malanowski, Cibulka, Singh et al., Pintos et al., Calvo et al., and other related equations.
|
|---|
