Hydro-co-processing of a jatropha oil and gas oil blend with a sulfided Ni–W catalyst supported on mesostructured materials Al(x)-SBA-15 type for cleaner hybrid diesel production: Effect of the Al/Si molar ratio

Obtaining cleaner hybrid diesel fractions by hydro-co-processing vegetable oil and gas oil blends requires tailoring intrinsic properties (metal content and acidity) of a solid catalyst. Such catalyst must promote the hydrodesulfurization (HDS), hydrodeoxygenation (HDO), and hydrocracking (HCK) reactions. In that sense, the present research work reports the synthesis (sol–gel and hydrothermal), characterization (N2 physisorption, XRD, HR-TEM, 27Al-MAS-NMR, Pyridine-FTIR, and RAMAN spectroscopy), and catalytic evaluation (6 MPa of H2 initial pressure, 360 °C, and 4 h) for Ni–W/Al(x)-SBA-15 sulfided catalysts during the hydroprocessing of a 20 vol% of Jatropha Curcas L. oil blend with a mixed gas oil (50 vol% LGO and 50 vol% HGO). Metal content of the catalysts was fixed at 2.5 wt% of NiO and 15 wt% of WO3, meanwhile, the Al/Si (x) molar ratio was adjusted in 0.1, 0.05, 0.033, 0.025, and 0.0 to study the effect of aluminum (Al) content during hydroprocessing. Liquid products were analyzed by FTIR, 1H NMR, ESI-MS, Simulated Distillation (ASTM D2887) and ASTM D4294 for S content. The effect of Al incorporation was mainly observed in the hydrotreating reactions (HDO and HDS) rather than HCK reactions. Intermediate Al/Si molar ratios (0.05, and 0.03) promoted the highest sulfur removal of about 13.1 % compared with the 10.7 % and 5.6 % for 0.1 and 0.025 Al/Si molar ratios, respectively. In addition, the highest content of Brønsted (0.05 mmol g−1) and Lewis (1.45 mmol g−1) acid sites was observed for the Ni–W/Al(0.05)-SBA-15 catalyst. Regarding HDO activity, it was the highest (57.3 %) for Ni–W/Al(0.1)-SBA-15 catalyst, and the lowest (30.9 %) for Ni–W/Al(0.025)-SBA-15, and Ni–W/Al(0.0)-SBA.15 sulfided catalysts. Finally, by comparing HDS and HCK activities of Ni–W/Al(0.05)-SBA-15 and Ni–W/Al(0.0)-SBA-15 sulfided catalysts, it was observed that HDS decreased 7.5 % and HCK increased 2.4 % when no Al was incorporated.