Study On The Preparation And Properties Of Manganese Based Low-temperature SCR Catalyst For Denitration In Cement Kiln

With the rapid development of cement industry, the emission of NOX from the cement exhaust gas accounted for the total emission of NOX increases continuously, and then finding a way to control NOX from cement industry must be solved. Because low-temperature selective catalytic redution(SCR) of NOX has attracted interests for its high catalytic activity and energe efficiency, it is very suitable for cement industry to control NOx.However now the activity of low-temperature SCR catalysts is not very high in low-temperatuer range.Furthermore, the reaction and poison mechanisms are not very clear.These lead the SCR can not been used to control NOX from cement plant. In order to solve these problems,the activity and reaction mechanism of the catalyst which used P25nano TiO2as the carrier and MnOx as the active component was investigated.A series of catalysts with different precursors,ratios of Mn/Ti and calcination temperatues were prepared by impregnation method. And then their catalytic activity were compared to choose the highest. At last, we the best catalyst which used Mn(CH3COOH)2as the precursor the ratio of Mn/Ti as0.4calcinated at500℃was got. The91.2%NOX conversion was obtained at180℃.From the characterization of the catalysts by XRD,XPS,TEM,BET and so on, it was found that axsiting form and dispersion of MnOX,surface area and the concentration of lattice oxygen would effect the catalytic activity. Furthermore, the effects on space velocity,concentration of O2and NH3also were investigated and the kinetic study was used to calculate the activity energe which could compare the activity of catalysts.In order to improve the catalytic activity, the transition metel Fe was added to the catalyst. The catalyst was prepared by impregnation method with used P25nano TiO2as the carrier,MnOX as the active componen and FeOx as the catalytic promoter. It was found that the addition of Fe could deeply improve the catalytic activity. Furthermore, a series of catalysts with diffierent ratios of Fe/Ti and calcination temperatues were prepared to find the best. At last, the best catalyst was been found which had ratio of Fe/Ti as0.05calcinated at500℃, above50%NOX conversion was obtained at80℃.From the characterization of the catalysts by XRD,BET and TG-DSC, it was found that addtion of Fe could improve the nano-structure and the dispersion of the active component, which contributed to higher NO removal. Meanwhile, Fe had the cooperation with Mn which could also improve the catalytic activity.