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Characterization of preparation factor influence on Ni-Mo/Al/sub 2/O/sub 3/ hydrotreating catalysts

Thesis/Dissertation ·
OSTI ID:7152097

This work was undertaken to better understand the catalyst structures of the nickel-promoted molybdena on alumina (Ni-Mo/Al/sub 2/O/sub 3/) catalyst, to provide improved design principles, and to establish simple activity oriented tests. Industrial production routes were used to prepare a series of catalysts with various MoO/sub 3/ and NiO contents: 10-20 and 0-7 wt%, respectively. Calcination, in the range of 300-700/sup 0/C, was attempted in the laboratory. Also studied were selected commercial catalysts as development references. Catalysts characterization was accomplished through combined thermal (TGA, TPR), surface (XPS), reactivity (thiophene HDS), adsorption (DOC), as well as a magnetic and acid extraction studies. A structural scheme, describing all the identified Ni and Mo phases, was established. In addition, this scheme presents the resemblance between the sulfided Mo structure and oxidic monolayer, which explains why the original activity can be returned and, in some cases, enhanced after severe regeneration procedures. Guides to an optimized catalyst were also proposed. The impregnation sequence-first Ni and then Mo- was though to be important in preparing more active catalysts, having smaller Mo islands and more tetrahedral Ni. For a ..gamma..-Al/sub 2/O/sub 3/ support of 250 m/sup 2//g surface area, the optimal NiO and MoO/sub 3/ loadings were deduced to be 1.0-1.5 and 16-18 wt% respectively. Calcination at 500/sup 0/C was found to yield the most tetrahedral Ni.

Research Organization:
Houston Univ., TX (USA)
OSTI ID:
7152097
Country of Publication:
United States
Language:
English