Influence Of Calcination Temperature On So(2)Resistance Of Mn-Fe-Sn/Tio(2)Catalysts At Low-Temperature

The Mn-Fe-Sn/TiO2(MFST) catalysts for NO and Hg co-removal with SO(2)resistance at low temperature were prepared by the impregnation method under different calcination temperatures (300, 400, 500, and 600 degrees C). The influences of calcination temperatures on SO(2)resistance and of SO(2)concentration on both denitration and demercuration performances of the Mn-Fe-Sn/TiO(2)catalysts were investigated in a fixed-bed reaction system. Surface physicochemical characteristics and SO(2)resistance mechanism of MFST catalysts were analyzed by means of Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), H-2-temperature-programmed reduction (H-2-TPR), and X-ray photoelectron spectroscopy (XPS). The results showed that the NO and Hg(0)removal efficiency of the MFST catalysts was not affected by reaction temperature between 200-280 degrees C in the absence of SO2. However, the NO and Hg(0)removal efficiency was affected mostly in SO2-containing atmosphere. Appropriate calcination temperature can alleviate SO(2)poisoning and improve catalytic activity. When the calcination temperature was below 500 degrees C, MFST catalysts have good resistance to the SO2, and it was found that at calcination temperature of 400 degrees C, the NO and Hg(0)removal efficiency had the minimum decay from 95% to 70% and 99% to 93% at 700 ppm SO2, respectively, which was higher than that of other catalysts. That was mainly due to the abundant BET surface area and pore parameters and the high ratio of Mn4+/(Mn4++ Mn3+), Fe3+/(Fe3++ Fe2+), and O-alpha/(O-alpha+ O-beta) on catalyst surface. At lower calcination temperature (<= 400 degrees C), the metal active ingredient did not calcined sufficiently that made the NO and Hg(0)removal efficiency declined. While at higher calcination temperature (>400 degrees C), the catalyst tended to agglomeration and MnO(2)was converted into Mn(2)O(3)gradually. Furthermore, doping Fe and Sn can effectively reduce the consumption of Mn4+, which greatly improved the catalytic activity and the SO(2)resistance.