A Study On Hydrocracking Reaction Of Bicyclic Compound Over Zeolite Catalysts

In order to increase the productivity of the targeted product on the hydrocracking catalysts, and to satisfy with the stringent environmental legislation and the more demands of the middle distillate fractions,the change trend of the hydrocracking reactant and the distribution of the hydrocracking product were investigated on hydrocracking catalysts. Firstly, the activity of four hydrocracking catalysts (catalyst A, catalyst B, catalyst C, and catalyst D) was investigated by the different aromatic content of reactant. The optimum catalyst was gotten according to the reaction results determined. Secondly, the optimum process of the hydrocracking catalysts presulfuration, and the influence of the aromatic hydrocarbon content in reactant and the temperature of the hydrocracking on the catalysts activity were studied on this catalyst and the optimum reaction parameters were got; lastly, the dynamics of the catalysts were investigated at the optimum reaction conditions according to the above analyses.Through the analyses of the VGO hydrogenation cracking reactant composition, the key process of the VGO hydrogenation cracking conversion on the hydrogenation cracking catalysts is the conversion of cycloalkane and aromatics. The thesis studied hydrocracking rules on catalysts by taking decalin and tetralin as probe molecules. The aroma tolerance of catalysts with four different carriers was also studied. The activity of catalysts and hydrocracking products distribution show that catalyst A is optimal.The influences of the hydrocracking catalysts presulfuration, the aromatic hydrocarbon content and the temperature of the reaction on the activity of the catalysts were studied on the catalyst A. The result shows that with the increase in the aromatic hydrocarbon content, the conversion of the model compound decreases, the content of heavy component product increases and the activity and life of the catalysts were rapidly reduced. So the content of the aromatic hydrocarbon in the reactant must be limited to insure the production efficient and chronical. The content of aromatic hydrocarbon in reactant was set limit to 10% according to the analyses data of hydrotreating DaQing VGO reactant composition. Activities of catalysts and the rate constant of the hydrocracking rise with the increasing of the reaction temperature, which lead to the conversion of model compound increases and the complicated composition of the product. Meanwhile the activity of the catalyst decreased with rapidly increased of the dehydrogenation product. Thus the optimum temperature of the reaction is 340℃.Finally, the kinetics of the hydrocracking reaction on the catalyst A under optimum conditions were studied and the rate constant (k) and activation energy (Ea) were ascertained which offered foundations to the improvement of the hydrocracking reaction.