Hydrodesulfurization and hydrocracking of Maya crude with P-modified NiMo/Al2O3 catalysts

In the present work we analyze the changes in hydrocracking, hydrodesulfurization, hydrodeasphaltenization, and hydrodesmetallization, during the hydrotreating of Maya crude, when 3.4 wt.% of P2O5 is incorporated by two different routes to a NiMo/Al2O3 catalyst. The catalysts were characterized by nitrogen physisorption, XRD, HRTEM, SEM, and CO adsorption analyzed by FTIR. Additionally, to obtain deeper knowledge on the reaction system, the catalysts were also tested in the HDS of 4,6-DMDBT, and hydrocracking of cumene. NiMo/PAl2O3 shows the highest HDS activity for 4,6-DMDBT, the better hydrogenating properties, and the best performance in all the reactions during hydrotreating of Maya crude. The acidity and porosity of the catalyst are determinant factor for the conversion of atmospheric residue. At similar acidity, the porosity defines the best catalyst and conversely, at similar porosity, acidity will define the activity of the catalyst. However, an excess of acidity in the catalyst can lead to rapid deactivation. NiMo/PAl2O3 displays superior performance compared to NiMo/Al2O3 and NiMoP/Al2O3 because it presents the best combination of acidity, porosity and distribution of the sulfided Ni and Mo phases, which provide the hydrodesulfurization and hydrogenating functions. (C) 2011 Elsevier Ltd. All rights reserved.