The Modification Of Ultrafine Nickel Alloy NiO-MoO₃/Al₂O₃-TiO₂ Catalyst In The Hydrogenation Of Aromatics

According to this work in reproducibility, selectivity and stability of ultra-fine nickel based NiO-MoO₃/Al₂O₃-TiO₂ catalysts, which suited for hydrodearomatics of jet fuel from Nanjing Refinery to produce high quality odorless kerosene, the optimal formulation of the catalysts were selected.The physi-chemical and textural properties of catalysts were characterized by ICP, N₂ adsorption and XRD. The acidity on the catalysts was measured by butyamine-temperature-programmed desorption (C₄H₉NH₂-TPD), and temperature-programmed reduction (TPR) was performed to monitor the reduction behavior of Ni crystallites on surfaces and the interaction of Ni species on supports with hydrogen. In the continuous fixed bed reactor, the deep hydrodearomatics of jet fuel over above-mentioned catalysts were carried out.Compared with other catalysts prepared by conventional methods, the ultra-fine nickel loaded catalysts produced by in-situ sol- gel method had higher performance of hydrodearomatics. In this way, SKC type catalysts had larger specific surface, and more proper pore structure. The surface properties and acid strength of catalysts could be modified by SiO₂ promoter introduced by in-situ sol-gel technology.Applying L₁₆(4³) orthogonal table, SKCX type catalysts with various amounts of promoters were prepared. Depending on the results of activity and stability of the catalysts, based on the total weight of catalysts, from 8.0 to 10.0 wt. % of SiO₂ was chosen. The performance of SKCX type catalysts was improved.At the same time, the hydrogen-uptake ability and activity of the catalysts with certain amounts of promoters were affected by different molar ratios of Ni/Mo.When the weight percentages of NiO and MoO₃ were increased, and molar ratios of Ni/Mo was reduced, the activity, selectivity and lifespan of catalysts were inhanced. Using the catalysts with about 30% of total metal content, aromatics mass fraction of oil products was less than 50μg.g-1. The performance of hydrodearomatics and stability of catalysts were better than ones of commercial catalyst.The effect of dearomation of SKCX type catalysts was influenced by pre-reduction temperature. The reactions of hydrodearomatics in jet fule system were deeply impacted by reaction factors, such as, reaction temperature, reaction pressure, and LHSV, etc. Finally, the reaction conditions were optimized.According to approved compositions, the manufacture of the catalyst was scaled up and 1 tone of catalyst sample was provided for using in pilot plant in Nanjing Refinery. The experimental results showed that the activity, selectivity, and stability of the sample in hydrodearomatics of jet fuel were closed to ones of catalysts made in laboratory.