Preparation, Characterization, and Kinetics Model of MoCo/γ-Al۲O۳ Catalysts for Oxidative Desulfurization of Light Naphtha

The subject of this work is to study the effect of pH, molybdenum content and some of the transition metals (such as Vanadium, Chromium, Manganese, Iron, Cobalt, Nickel) on the catalyst properties and performance of oxidative desulfurization (ODS). To achieve this aim, the mesoporous ۵%Co۱۰%Mo/γ-Al۲O۳ catalyst was prepared by incipient wetness impregnation method. Then, the as-synthesized catalysts were characterized by X-Ray Diffraction (XRD), N۲-adsorption/desorption, and Inductively Coupled Plasma Mass Spectrometry (ICP-MS), Scanning Electron Microscopy (SEM) and NH۳-Temperature Programmed Desorption (NH۳-TPD). The catalytic activity was measured with catalytic ODS setup. The catalyst with ۱۰wt%Mo (as an active metal) and ۵wt%Co content (as a promoter) at pH=۴ represented the optimum performance for oxidative desulfurization. The ۵%Co۱۰%Mo/γ-Al۲O۳ has the Surface Area =۱۷۰.۶۱ m۲/g, Pore Volume =۰.۶۴ cm۳/g, Average Pore Diameter = ۱۵.۱۸nm when these parameters were increased, it led to the best operation condition of sulfur removal. The SEM images showed that the application of Co and Mo metals reaches more homogenous impregnation. The NH۳-TPD result introduced the strong acidic sites of ۵%Co۱۰%Mo/γ-Al۲O۳. The obtained results proved that the total sulfur (all kind of sulfur in the feed) of light naphtha decreased from ۱۶۰ppm to ۲۰ppm during ODS process with the optimized catalyst. In that case, the kinetics of oxidative desulfurization of the optimized catalyst (۵%Co۱۰%Mo/γ-Al۲O۳) was studied. Moreover, a kinetic affinity model was utilized to determine the kinetic parameters of this reaction and the modeling results showed good agreement with experimental data.

کلیدواژه ها:

Oxidative desulfurization catalyst ، MoCo/γ-Al۲O۳ ، light naphtha ، Kinetics Affinity Model