Study On Molding And Performance Of MnO_x-CeO₂/TiO₂Catalytic Material For SCR Of NO_x With NH₃at Low Temperature

Nitrogen oxide is one of the atmospheric pollutants. In2011, nitrogen oxideemission has already up to24.04million tons in China. So the emission reduction ofnitrogen oxide is extremely urgent. At present, the nitrogen oxide emission in cementkilns is about2.20million tons every year, accounting for about10%of the nationalnitrogen oxide emission. The selective catalytic reduction technology is the mostpromising denitration technology in the cement kilns, which has great significance fornitrogen oxide emission reduction in cement kilns. The key of selective catalyticreduction technology is the low temperature denitration catalytic material. Currently,there are a lot of researchs on MnO_x-CeO₂/TiO₂low temperature denitration catalyticmaterial, but they are concentrated on the powdered catalytic material activity. Themolding process of the catalytic material also not perfect, and the molding processparameters is not clear. It had hindered the application of MnO_x-CeO₂/TiO₂low-temperature denitration catalytic material in actual industria.The molding process and performance of MnO_x-CeO₂/TiO₂catalytic materialwere researched in this paper. First,the powdered catalytic materials were preparedusing aqueous solutions of three manganese salt as well as cerous nitrate andTiO₂（anatase） powder by impregnation method, and acquired the best processparameters of powdered catalytic material. Second, the sheet catalytic materials wereprepared by different methods, and acquired the relationship between molding processparameters and performances. Last, the honeycomb catalytic material was prepared,and the denitrationin activity under different operating conditions were tested.The results showed that, the powdered catalytic material had good activity at lowtemperature, which used manganese acetate as precursor and calcined at450℃, andthe denitrification rate could reach to83%at150℃. When the sheet catalyticmaterials were prepared by impregnation-molding method, binder and calcinedtemperature had significant effects on performance of catalytic materials, and the bestprocess parameters were that binder was silica sol, molding pressure was4MPa,calcined temperature was400℃, and the denitrification rate could reach to81%at180℃. When the sheet catalytic materials were prepared by molding-impregnationmethod, dipping time had significant effects on performance of catalytic materials,and the best process parameters were that dipping temperature was80℃, singledipping time was15h and dipping time was3times, and the denitrification rate couldreach to82%at120℃. The honeycomb catalytic material was prepared by extrusionmolding method. When NOx concentration was500¹500ppm, space velocity was9000⁴5000h^-1and the ratio of NH₃/NO_x was0.8¹.2:1.0, the honeycomb catalytic material had good low temperature activity, and the denitrification rate could be up to80%at180℃.