Study On The NO Conversion And Resistance To SO₂of Mn Based Catalysts

Emissions of nitrogen oxides （NOx） in fuel combustion are one of the mostnotorious gaseous pollutants that cause a variety of environmentally harmful effectssuch as the formation of ozone depletion, photochemical smog and acid rain, whichendanger human health. Selective catalytic reduction （SCR） of NOxto N2is one of themost effective methods for denitrification of flue gas, among which catalyst is the keyelement of the DeNOxsystem. More attention to manganese oxide-based catalysts hasbeen paid due to their excellent catalytic reduction of NOxby NH3（NH3-SCR） at alow temperature in recent years.In this thesis, manganese nitrate and and manganese acetate were used in themanganese oxide-based catalyst supported on titanium dioxide by impregnation andsol-gel method, in order to study the performance of element Mn. The Mn-Ce/TiO₂catalyst maintained a smooth catalytic performance at150-350℃;The NOxconversion of Mn-Ce-W/TiO₂and Mn-Ce-W-V/TiO₂catalysts could reach90%at170℃; For Cu played a positive role on catalytic performance at high temperature,when Cu reacted with Ce, it had a negative effect to catalytic performance at Lowtemperature, high catalytic performance point of Mn-Ce-W-V-Cu/TiO₂catalyst movedto a higher temperature. In all, Mn exhibited an active performance for lowtemperature selective catalytic reduction of NO with NH3. the SCR catalysts preparedby sol-gel method have high activity.The TiO₂carrier supported V2O5with different metal oxides（Fe、V、Co、Ce） wasprepared by impregnation. The catalytic activity was investigated by using the methodof temperature progressing and urea was used as reductant. The results of activityactive test, it shows that NO conversion on Fe-Mn-Ce/TiO₂is100%at150⁴00℃,which performes much better than that on V-Mn-Ce/TiO₂and Co-Mn-Ce/TiO₂. Andthe complex catalyst Fe-Mn-Ce/TiO₂shows high resistance to SO₂, on which NOconversion is above80%at150⁴00℃.The catalytic samples were characterized by BET, XRD, TPD and XPStechniques. The research results showed that the larger BET surface area of thecatalysts may contribute to improve catalyst activity; there is not a linear relationship between peak temperature or peak area and activity; The active components in thesurface of two kinds of catalysts is existed in the form of grain. The more V4+existedin the catalyst surface, the higher NO conversion was obtained.