Desulfurization of diesel using ion-exchanged zeolites

As the restrictions by governments worldwide on lowering of sulfur content in transportation fuels are getting more stringent, the search for alternatives to conventional hydrodesulfurization process is attracting numerous studies on desulfurization. In the present work, we report studies on sulfur removal to acceptable levels by using adsorption process at room temperature. Y-zeolites, ion exchanged with metal ions that are capable of (pi)-complexation, have been studied for their usefulness in desulfurization of diesel. Studies have been carried out on a model diesel comprising all the major refractory sulfur compounds such as benzothiophene, dibenzothiophene and 4,6 -dimethyl dibenzothiophene and also on commercial diesel. A very high sulfur removal capacity has been observed for Ni-Y (~42mg/g)) and Cu-Y (~31mg/g)zeolites. These along with other ion-exchanged zeolites such as Fe-Y and Zn-Y have been found to effectively remove sulfur from commercial diesel, although the capacity in the later case was lower than that observed with model diesel.