Effects On Catalysts For Catalytic Cracking By The Parameters Change Of Reaction-regeneration System

On the condition that environmental protection, saving and to increase refinery economicprofits are advocated, a new type of highly efficient catalysts, the optimization of catalyticcracking craft and energy system have been the most studied. However, to improve the effectof heavy oil catalytic cracking, not only catalysts with higher performance, but theimprovement in its corresponding operating process and energy system is also very important.Reasons for deactivation of catalysts have been analyzed in this paper from the basictheory of catalytic cracking reaction. On catalytic cracking unit which is the load of catalyticcracking reaction, the technical process of catalytic cracking reaction is introduced in detail.Through the comparative analysis in advantages and disadvantages of stream and dry gas aspre-lifting gases in actual production, dry gas pre-lifting technology is feasible and beneficial.That is the burning situation of catalysts to the energy change of reactor-regenerator system isdiscussed in this paper, thus to optimize energy system.The physicochemical characterization and micro-activity test to the catalysts includingfresh catalyst and the catalysts pre-lifted by100%dry gas,50%dry gas and50%steam,100%steam, respectively, have been carried on in the paper. The differences in properties ofcatalysts under different pre-lifting conditions (catalyst activity, crystallinity, framework Si/Alratio, pore structure, catalyst carbon deposition, acidic sites distribution etc.) are furtherstudied.Through discussion to the burning situation of catalysts, favorable regeneration canensure catalyst activity, improve the yield of light oil and decrease catalyst consumption etc.The results of test to catalyst activity show that the activity of the regenerated catalystpre-lifted by dry gas was higher and came down more slowly as a function of the catalyststime on stream, which means longer service time of catalyst. The results of XRD and IR showthat the catalyst pre-lifted by dry gas has higher framework of Si/Al ratio and keeps bettercrystallinity. The results of BET show that the catalyst pre-lifted by dry gas has larger poreradius can benefit for big molecular catalytic cracking reaction. The analysis results of cokeshow that the coke content which is one of the main factors to impact catalyst activity is lessunder dry gas pre-lifting condition. It can be concluded that dry gas pre-lifting technology canresist coke to lengthen the regenerated period of catalyst. The results of NH3-TPD show thatthe catalyst pre-lifted by dry gas with larger strong acid content and less weak acid content isin agreement with the result of XRD. The weak-medium acid decreased much more under drygas pre-lifting condition in catalysis. Furthermore, the properties of catalyst pre-lifted by100%dry gas are the best.