2002 Volume 45 Issue 5 Pages 279-287
Hydrocracking of Arabian heavy vacuum residue was investigated over alumina-supported nickel molybdenum catalyst (Ni-Mo/Al2O3), unsupported nickel molybdenum catalyst (Ni-Mo) and unsupported molybdenum catalyst (Mo), under hydrogen at 8MPa (cold charge)and at 410°C, using a swing micro-autoclave of 140ml inner volume. Using Ni-Mo/Al2O3, asphaltene (Asp.) was cracked almost completely to yield hexane soluble fraction (HS), increasing with reaction time, to a maximum of 60% at reaction time of 4h. The remaining HS in the reaction had a higher H/C value, much lower sulfur concentration and lower nitrogen concentration compared to the HS in the feedstock. However, ca. 30% of HS remained after 4h reaction, suggesting that the fraction stable against thermal cracking was concentrated. Ni-Mo showed lower activity for Asp, cracking and lower yield of distillable fraction (VD) than Ni-Mo/Al2O3. Fresh Ni-Mo showed higher activity for 1-methylnaphthalene hydrogenation than fresh Ni-Mo/Al2O3, but spent Ni-Mo showed lower hydrogenation activity than Ni-Mo/Al2O3 suggesting that Ni-Mo loses hydrogenation activity fairly rapidly in the above reaction. Using Mo catalyst, comparable yield of VD and higher yield of Asp. were obtained compared to using Ni-Mo/Al2O3, and a similar amount of tetrahydrofuran insoluble fraction compared to the thermal reaction.