(50c) Pilot Experiments of a Novel Catalytic Distillation Process for Sulfur Removal of FCC Gasoline

The environmental restriction regarding sulfur content in transportation fuels is currently one of the most important issues. Since major sulfur compounds in gasoline come from the fluid catalytic cracking (FCC) naphtha cut, sulfur removal of FCC naphtha is, therefore, essential for attaining the clean gasoline.

This paper will present pilot experiments of a novel catalytic distillation process for sulfur removal of FCC naphtha in a column packed with structural catalytic distillation cells containing Amberlyst35 resins. In comparison to the conventional hydrodesulfurization, this process can be conducted under mild conditions (Pressure of the catalytic distillation column is 100kPa and temperature of the bottom is lower than 150℃) and will consume lesser hydrogen.

In this process, thiophene and methyl-thiophenic compounds react with low carbon alkenes to form higher boiling point thiophenic derivatives, as well as mercaptans are etherified to higher boiling point alkyl-sulfides. Then, the higher boiling point sulfides are removed from light fractions by distillation and concentrated in the heavy fractions. Consequently, the sulfur free light cut is obtained from the top of distillation column. the fraction cut point can be raised from 75℃ to 120℃, which will prevent olefins (with boiling point below 120℃) from saturation at the condition of hydrodesulfurization and avoid octane number loss with deeper desulfurization. This study would be of useful references to further industrial application of desulfurization of FCC gasoline.