Effect Of Promoters On The Denitrification Activity And Sulfur Resistance Of Fe-Mn Catalysts At Low Temperature

Reducing NOx emissions from flue gas is an important issue in environmental management currently.The catalyst with TiO₂ as support and Fe-Mn as active component has excellent NH3-SCR activity but poor SO2 resistance at low temperatures.Promoters were used to improve the NH3-SCR activity and SO2 resistance of 0.1Fe-0.1Mn/TiO₂ catalyst.The mechanism of promoter-modification on the catalytic performance was discussed in detail.The promotive effect of different promoters impregnation doping on the performance of 0.1Fe-0.1Mn/TiO₂ catalyst is from Pr > La > Sm > Co > Sm Co.The influence of preparation methods on the Pr modified catalyst was investigated.The low-temperature activity from high to low is as follows: impregnation > sol-gel > coprecipitation.Pr-modified 0.1Fe-0.1Mn-x Pr/TiO₂ catalysts with high activity and excellent SO2 and H2 O resistance were prepared by the impregnation method and used for the NH3-SCR at low-temperatures.Pr can inhibit Fe Ox and Mn Ox crystallization and stabilize the high valence states of Fe and Mn,maintaining the catalyst's high activity and stability.Doping with Pr diminished the ammonium sulfate deposition and alleviated the sulfation,improving the catalysts' sulfur resistance.The presence of H2 O can prevent the sulfation of metal ions and make SO2 poisoning reversible.0.1Fe-0.1Mn/TiO₂?x La?catalyst of La modified TiO₂ support prepared by the solgel method significantly improved the SO2 resistance,which was better than 0.1Fe-0.1Mn-0.02La/TiO₂ catalyst prepared by impregnation method.La doping can inhibit the growth of TiO₂ grains,make TiO₂ support appear obvious layered structure,produce more mesopores,improve the specific surface area of the catalyst,which is conducive to the decomposition of ammonium sulfate,and ease the sulfation of Fe,Mn,and Ti.La can weaken the deposition of ammonium sulfate on the surface of the catalyst,reduce the degree of sulfation of active components,so that it maintains high SO2 resistance activity of the catalyst.Figure 36;Table 5;Reference 132...