Background: Residue hydroprocessing is the most important processes in the refinery to
obtain transportation fuels from the low quality petroleum resources. But the upgradation of residues is
a difficult task, due to the presence of high contaminants such as sulfur, metals (Ni and V), asphaltenes
and residue carbon, which cause rapid deactivation of the catalysts. The most effective approach to
control catalyst deactivation is the use of the mesoporous alumina as support. Mesoporous γ-aluminas
through a sol-gel method was synthesized without using any surfactant or templates. The synthesized
highly porous aluminas are used to prepare NiMo catalysts for the hydroprocessing of vacuum residues.
Methods: In the present work, an attempt has been made to synthesize large pore mesoporous alumna
with better thermal stability in a very simple way by using different alcoholic solvents. NiMo catalysts
were further prepared using synthesized aluminas using sequential impregnation method. The catalytic
activity has been evaluated using vacuum residue as feed having 21.98wt% asphaltene in a batch
Results: The mesoporous alumina synthesized using isopropanol as solvent had a wide porosity with
appropriate surface area. The number of total acid sites is more for the mesoporous alumina synthesized
using mixture of solvents (isopropanol and butanol). The ratio of octahedral/tetrahedral species in
catalysts prepared by isopropanol is quite high indicating that the presence of weakly bonded octahedral
species in this catalyst is higher than that of catalysts prepared by mixture of solvents. Hydrotreating
activity suggests that due to the presence of high concentration of octahedral species in NiMo/Al2O3
catalysts prepared by isopropanol has high hydrogenation activity and hence shows higher HDM, HDS
and HDAs conversions.
Conclusion: A simple, convenient and effective way is used to synthesize mesoporous alumina as
support for the NiMo hydrotreating catalysts. Residue hydrotreating activity of the catalysts suggests
that the coke formation by NiMo catalysts prepared by isopropanol is very low due to the presence of
large porous structure and high hydrogenation activity of the catalyst. It is also found that the catalyst
having higher total acidity facilitates coke formation.