Kinetic Study And Cfd Simulation On Multi-Stage Catalytic Removal Of The Exhaust Gases From Acrylonitrile Plant

Acrylonitrile is an important chemical raw material in the petrochemical industry.Most of the domestic manufacturers of acrylonitrile use the propylene ammoxidation process developed by BP.During the production process,the absorption tower will emit a certain amount of organic waste gas,including C3H3N,CO,C3H6 and C3H8.As environmental protection standards become more stringent and standardized,combined catalytic technology capable of synergistically removing multiple pollutant components has become an urgent need for effective treatment of industrial waste gas.In this paper,a large number of literatures and experimental studies have been carried out to determine the best catalysts for the effective removal of acrylonitrile-containing exhaust gases(Cu/ZSM-5 and Pd/Al2O3 zeolite catalysts),and catalysts with different loadings are prepared by impregnation method.The prepared catalyst was characterized by characterization methods such as XRD,SEM and XPS.The catalytic evaluation effect of acrylonitrile-containing exhaust gases on the two catalysts was studied by the independent evaluation device established by the laboratory,and the optimal loading of the catalyst was determined(wt%=5%Cu/ZSM-5 and wt%=0.1%Pd/Al2O3).The optimum combination order for removing acrylonitrile-containing exhaust gases is obtained by changing the order of catalyst combination:the weakly oxidizing catalyst is placed on the front,the acrylonitrile is converted to N2 by selective catalytic oxidation,and the strong oxidizing catalyst is placed on the behind,the hydrocarbon compound is converted to H2O and CO2 by selective catalytic oxidation.In addition,by establishing a kinetic microscopic kinetic model of the combustion reaction of acrylonitrile-containing exhaust gases on Cu/ZSM-5 catalyst,the intrinsic kinetic experimental data is obtained under the premise of eliminating the influence of internal and external diffusion,the kinetic parameters of acrylonitrile-containing exhaust gases on Cu/ZSM-5 catalyst were obtained by using MATLAB analysis software and multi-step Runge-Kutta equation iteration.This paper also uses the computational fluid dynamics tool(CFD)to establish a two-dimensional multi-stage combined catalytic reactor,discusses the reactor parameters such as reactor pressure drop,temperature and component concentration,and provides technical reference for engineering applications.