Sulfur free supported MoCx and MoNx catalysts for the hydrotreatment of atmospheric gasoil and its blends with rapeseed oil

Abstract

Generally, the commercial catalysts for hydrotreatment in refineries are supported sulfide transition-metal-based catalysts. However, the co-processing of vegetable oils reduces their hydrodesulfurization (HDS) efficiency by leaching sulfur from the active sites of the catalyst. The present work reports the use of six sulfur-free MoCx and MoNx catalysts (supporter with Al2O3, TiO2 or ZrO2) for the hydrotreatment of atmospheric gasoil (AGO) and co-processing of rapeseed oil (RSO – 5, 10 and 25 wt%). The screening tests were carried out in a fixed bed reactor at industrial operating conditions (330–350 °C, 5.5 MPa, WHSV = 1–2 h−1). Higher reaction temperatures and lower WHSV had a positive effect on catalyst activity and product quality. In case of co-processing, the hydrodeoxygenation reaction mechanism was found to be dominant, producing n-C16 and n-C18 n-alkanes at all AGO/RSO ratios used. Overall, our results suggest that alumina supported catalysts are the most promising materials, exhibiting a combination of excellent stability, high activity and no negative effects on HDS efficiency during AGO/RSO co-processing.