Hydrogenation And Dehydrogenation Study On Nickel-based Catalyst

Cyclohexane is a very important chemical raw material. Along with the development of environment protection, removal of aromatics from solvent and fuel is of great importance, and one of the most effective ways is hydro-aromatics (HDA). At the present time, the hydrofing catalyst made in China could not meet the great demand of petrochemical development. Thus, it is practically significant to develop a new hydrogenation catalyst with high catalytic performance for removal of aromatics.In this thesis, the supported nickel catalyst has been attempted to use for the hydrogenation of aromatics in fuel oils in order to find an effective catalyst with high activity, selectivity and long lifetime.A series of supported nickel-based catalysts for the hydrogenation have been designed and prepared by the incipient impregnation and the sol-gel methods. The effects of supports, contents of nickel, calcination and reduction temperatures, promoters and preparation methods on the physical and chemical properties of catalysts have been characterized, using the technologies of nitrogen adsorption-desorption (BET), X-ray diffraction (XRD), Sanning electron microscopy (SEM), temperature programmed reduction (TPR)and the activity, selectivity and stability of the catalysts have been evaluated. Based on the thermodynamic and kinetic analyses for the dehydrogenation reaction, the kinetic model of Temkin type has been established, and the related kinetic parameters have been evaluated.It has been found that adding some Ti and Mo, the nickel-based catalyst, supported on SiO₂, prepared by sol-gel method, has showed the better activity and selectivity. compared with industry hydrogenation catalyst, it has better activity and stability ,therefore it will have a bright application future.