Preparation And Characterization Of Manganese-Based Catalysts

Nitrogen oxides, are one of the main pollutants atmospheric environment, cancause acid rain, photochemical smoke and a series of questions of damaging the earth.The control of nitrogen oxide emissions was increased by the state and will inevitablybecome more stringent. In recent years, selective catalytic reduction （SCR） of NO_xtechnology is economic and efficient, and it has high denitration efficiency, goodselectivity. It is used widely in the flue gas denitration of Coal-fired power plants.Catalyst is key in SCR technology, currently, most of the SCR catalysts are imported inChina. In monolithic catalysts which used TiO₂as carrier, TiO₂account for about80%of the total weight of catalysts. There are problems like insufficient use of highly activecomponent and high costs in this method.Based on improving these shortcomings of the catalysts, this paper has thefollowing work: Manganese-based catalysts are modified by WO₃﹑MoO₃toinvestigate the de-NO_x applications of tungsten supported manganese based catalysts. Acomposite support TiO₂/Al₂O₃was modified by MnO₂has been prepared via staticimpregnation method and used for the preparation of manganese-based SCRcatalyst.The catalysts were characterized by the X-ray diffraction method, SEM andBET technology. The activity for NO catalytic removal by NH₃has beenevaluated.During this process, the effect of preparation methods, temperature and anumber of factors to flue gas conditions have been researched.The results indicate that, compared to the catalysts supported on TiO₂（T）, thecatalysts supported on TiO₂-Al₂O₃（TA） have higher surface area and pore volume,which were beneficial to decentralize of active component MnO_x. The effects oftemperature, initial NO concentration, space velocity and NH₃/NO ratio on the SCRreaction have been investigated. The prepared catalyst showed a good activity, the NOconversion can be more than95%under the condition of350℃⁴00℃, the spacevelocity of10000h-1and NH₃/NO of0.8¹. Meanwhile, manganese-based catalystsshow the good catalytic activity and excellent stability at high temperature.Theemissions of nitrogen oxides was controlled effectively and showed great potential forpractical application.