Thesis (M.Eng.)--Chulalongkorn University, 2007

This thesis investigates thermodynamic study of etherification reactions between gasoline from fluidized catalytic cracking and ethanol by using a simulation program, Aspen plus version 11.1. The components of gasoline consist of carbon atom ranging from C4-C7. The group contribution methods (i.e. Ambrose’s method, Joback’s method, Gani’s method and Benson’s method) were applied to estimate the missing parameters (e.g. critical pressure, critical temperature, boiling point, stardard Gibb’s free energy of formation). The preliminary selection of group contribution method shows that Gani’s and Joback’s method are well-predicted for normal boiling point, critical temperature and critical pressure. Moreover Gani’s and Benson’s method showed good agreement with the properties from literatures for standard Gibb’s free energy of formation. Also, when applied the group contribution to Aspen plus simulator, Gani’s and Benson’s method yield the results close to those of experiments. However, Gani’s group contribution method cannot distinguish the properties of some components. The result found that 30 vol% of pure ethanol can be added to react with gasoline in order that the obtained product does not exceed the maximum allowable of ethanol in E10. The optimum etherification temperature for pure ethanol is 70°C.