Inhibition Effects of 2,6-Lutidine on the Hydrodesulphurization of Prepared Model Diesel Feedstocks Using CoMo/Al2O3 as Catalyst

Nowadays, streams from the secondary cracking processes present a gradual increment in the nitrogen content. They are used more frequently due to the increase of motor fuels consumption. However, the higher content of nitrogenous compounds negatively affects the desulfurization process, as these compounds act as inhibitors of active sites of a catalyst. Therefore, this study is focused on the effect of the addition of 2,6-Lutidine as a nitrogen component in the hydrodesulphurization of model diesel feedstocks. Totally 15 experiments with three levels of 2,6-Lutidine concentration (0-200-800 mg∙kg-1) under different conditions temperature (350 365-380°C) and pressure (3.0-4.5-6.0 MPa) were performed to evaluate the inhibition effect. All the experiments were carried out in a batch reactor with commercial CoMo/Al2O3 hydrotreating catalyst using hydrogenated gasoil. The model diesel feedstock was prepared by adding sulfur components - dibenzothiophene (DBT), 4-methyldibenzothiophene (4-MeDBT) and 4,6-diethyldibenzothiophene (4,6-diEtDBT) in the known concentrations (200 mg∙kg-1). The final liquid products were characterized in detail using GC PFPD (Gas Chromatography with Pulsed Flame Photometric Detection) methods. The reaction rate constants were calculated by linear regression and the desulfurization process was described. This mentioned procedure could be used for estimation of possible effects of nitrogen contaminants in the industrial process as well as for screening of catalysts activity.