Study On Process Of Ethylene Epoxidation On Silver Catalysts

The intrinsic kinetics experiments of ethylene epoxidation on commercial silver catalysts, YS-X, were proceed in an isothermal integral reactor under the conditions:2MPa, 200～255℃, gas composition C2H425～31%, CO2 7～12%, O25～-8% and without depressant. The intrinsic kinetics equation was obtained with Marquardt optimization method. The statistic tests proved that the calculated data of model was in agreement with the experimental data and the intrinsic kinetics model was reliable. The results could provide theoretical basis for catalyst engineering design.Based on the study of kinetics, research on the improvement of catalyst thermal conductivity and selectivity was conducted. The commercial silver catalyst andγ-Al2O3 particulates were wrapped in three-dimensional microfibous networks by using the papermaking/sintering processes. Ni microfibrous-structured commercial silver catalyst and Ni microfibrous-structured loading silver catalyst were prepared. The reaction of ethylene epoxidation over the two monolithic catalysts was carried out. The results showed that there was no ethylene oxide produced in the process and ethylene was converted to carbon oxide by oxidation. The causes of poor catalytic activity were found through various characterization methods (e.g., XRD,SEM,BET). The commercial silver catalyst particulates were easily deactivated in the process of roasting. High specific surfaceγ-Al2O3 particulates contributed to the contribution of silver, but resulted in high diffusion resistance and further oxidation of the products. If the preparation of carriers and catalysts can be improved, Ni microfibrous-structured packings will display the huge superiority.