(267g) Phase Behavior Modeling of Gasoline Systems

The vapor pressure of a gasoline is an important physical property that affects the performance of the fuel when it is used in internal combustion engines. A number of vapor pressure test methods have been standardized by the American Society for Testing and Materials (ASTM) to quantify the volatility characteristics of the automotive fuels. The prospect of using rigorous thermodynamic principles in conjunction with physical property models to represent the standard test methods and to assess the volatility characteristics of automotive gasoline is discussed. In particular, the prediction of the Reid vapor pressure and the representation of the differential vaporization behavior of gasoline mixtures are illustrated. Furthermore, a comparison of the performances of different equations of state in representing the phase behavior of mixtures of selected hydrocarbons and oxygenated additives is presented.