Utilization of Metal-Fouled Spent Residue Hydroprocessing Catalysts in the Preparation of an Active Hydrodemetallization Catalyst

Abstract

In the present work, studies were carried out with the objective of utilizing spent residue hydroprocessing catalysts, which contained coke and metal (V and Ni) deposits, in the preparation of active new catalysts that can be used for hydrodemetallization of residual oils. Three types of spent catalysts that contained different levels of vanadium, molybdenum, and nickel were used in the experiments. These catalysts were collected from different reactors (front, middle, and back-end) of an industrial atmospheric residue desulfurization unit. A series of catalysts were prepared by mixing and kneading of spent catalysts with boehmite in different proportions followed by extrusion of the resulting paste. All prepared catalysts were characterized by chemical analysis and by surface area, pore volume, and pore size measurements, and their hydrodesulfurization (HDS) and hydrodemetallization (HDM) activities were evaluated by hydrotreating tests in a fixed-bed reactor using Kuwait atmospheric residue as feed. A commercial HDM catalyst was also tested under the same operating conditions and its HDM and HDS activities were compared with that of the prepared catalysts. The results revealed that the catalysts prepared from spent catalyst/boehmite blends contained vanadium, molybdenum, and nickel. The relative concentrations of these metals (V, Mo and Ni) in the prepared catalysts and other key properties such as surface area, porosity, and crushing strength showed a strong dependence on the amount and the type of spent catalyst used in the preparation. Forty to 60 wt % of spent catalysts could be mixed with boehmite and extruded to produce active HDM catalysts. Catalysts prepared from the spent catalysts with low vanadium content such as those discarded from the back-end reactors of an atmospheric residue desulfurization unit were more active than a reference commercial HDM catalyst for promoting HDM and HDS reactions. The presence of some kind of new active sites involving a combination of the three metals Mo, Ni, and V together with the reasonably high surface area and porosity could be responsible for the high hydrotreating activity of the catalyst prepared by mixing spent catalyst with boehmite.

A novel sequential process of bioleaching and chemical leaching for dissolving Ni, V, and Mo from spent petroleum refinery catalyst

“…Catalyst materials, particularly those used in petroleum refineries, usually contain chemicals such as metals, metal oxides, and metal sulfides, which aid in hydrocarbon transformation to produce a full range of transportation fuels (Marafi and Stanislaus, 2003;Silvy, 2004). These catalysts lose their activity with time, after which they are regenerated and reused (Marafi et al, 2007). However, after a few cycles of regeneration and reuse, the catalysts are discarded as waste, because they are no longer useful for the refining process.…”

Bioleaching kinetics and multivariate analysis of spent petroleum catalyst dissolution using two acidophiles

“…The catalyst materials, especially those used in petroleum refineries, usually contain chemicals such as metals, metal oxides, and metal sulfides, which aid in hydrocarbon transformation to produce a full range of transportation fuels [3]. These catalysts lose their activity with time, and when the same decreased to the acceptable level, they are regenerated and reused [4]. However, after a few cycles of regeneration and reuse, the catalysts are discarded because they are no longer useful for pretreatment.…”

Catalyst deactivation pattern along a residue hydrotreating bench-scale reactor

“…In view of the related profiles of HDC activity and V-deposition, a V-compound could be responsible for the extra acidity observed. Accordingly, Marafi et al found enhanced hydrotreating activity when spent catalysts were regenerated and they suggest the formation of new active sites involving V, Mo, and Ni [48,49].…”