NiW/γ-Al2O3 catalysts prepared by modified equilibrium deposition filtration (MEDF) and non-dry impregnation (NDI) -: Characterization and catalytic activity evaluation for the production of low sulfur gasoline in a HDS pilot plant

The aim of this study was to investigate the desulfurization of fluid catalytic cracking (FCC) gasoline using NiW supported on gamma -Al2O3 catalysts prepared by conventional non-dry impregnation (NDI) method and a new one, the equilibrium deposition filtration, (EDF). The latter has been modified (MEDF) to produce the required catalyst quantity for its evaluation in a hydrodesulfurization (HDS) pilot plant. The modification of the typical EDF method showed that it is possible to apply the principles of this technique for practical catalyst preparations. In the first part of this work, the catalyst preparation methodology and the catalyst characterization results are presented. In the second part, the catalyst evaluation is described, in relation to a commercial catalyst, concerning their HDS, hydrogenation (HYG) and isomerization (ISO) activities. The main conclusion of this study was that the MEDF method is more promising than the conventional NDI method for preparing NiW hydrotreatment catalysts. The catalyst prepared by MEDF exhibited higher HDS activity than that of the NDI one, comparable to that of a commercial CoMo catalyst and the highest HYG and ISO activities. The enhanced catalytic activity of the NiW-MEDF catalyst was attributed to the high dispersity of the supported phases achieved by the corresponding preparation method. (C) 2001 Elsevier Science B.V. All rights reserved.