NiW/gamma-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 catal ytic cracking (FCC) gasoline using NiW supported on gamma -Al2O3 catalysts prepared by conventional non-dry impregnation (NDI) method and a new one, t he equilibrium deposition filtration, (EDF). The latter has been modified ( MEDF) to produce the required catalyst quantity for its evaluation in a hyd rodesulfurization (HDS) pilot plant. The modification of the typical EDF me thod showed that it is possible to apply the principles of this technique f or practical catalyst preparations. In the first part of this work, the cat alyst preparation methodology and the catalyst characterization results are presented. In the second part, the catalyst evaluation is described, in re lation to a commercial catalyst, concerning their HDS, hydrogenation (HYG) and isomerization (ISO) activities. The main conclusion of this study was t hat the MEDF method is more promising than the conventional NDI method for preparing NiW hydrotreatment catalysts. The catalyst prepared by MEDF exhib ited 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 enhanc ed catalytic activity of the NiW-MEDF catalyst was attributed to the high d ispersity of the supported phases achieved by the corresponding preparation method. (C) 2001 Elsevier Science B.V. All rights reserved.