ABSTRACT
A. Stanislaus, M. Marafi, and M. Absi-Halabi Petroleum Technology Department, Petroleum, Petrochemicals & Materials Division, Kuwait Institute for Scientific Research, P.O.Box 24885, 13109-SafatKuwait
I. ABSTRACT
Due to environmental concerns increasing emphasis has been placed in recent years on the development of processes for the rejuvenation of spent residual oil hydrotreating catalysts, which are deactivated by deposition of metals(e.g. vanadium) and coke. In the present work, the influence of foulant metal removal by chemical leaching on catalyst characteristics and performance was investigated as part of a research program on the rejuvenation of spent residual oil hydrotreating catalysts. The results revealed that the surface area and pore volume increased substantially with increasing vanadium extraction and the HDS activity showed a parallel increase. More than 85% of the catalyst initial HDS activity was recovered by removal of about 35% vanadium from the catalysts, although all carbon deposits remained on the catalyst. Extraction of more vanadium up to 90% by repeated extraction did not lead to further appreciable increase in surface area and activity. These results have been explained in terms of the location of vanadium as determined by electron microprobe analysis in the spent and treated catalysts and its role in catalyst deactivation.
