The Experimental Study On Catalytic Reduction Of NO Using Iron Oxide Impregnated Activated Char

With the development of our economic, the environmental pollution problem is getting worse and worse. The air pollution problems caused by NOX coming from the utilization of coal severely affected the atmospheric environment and human life.In order to control NOX emissions, a viable and low-cost sorbent was prepared for the removal of nitrogen oxides in the flue gas.In this paper, char-supported iron oxide catalysts from co-gasification of corncob and lignite were used for catalytic reduction of NO in flue gas. Flue gas denitrification experiments were carried out in a fixed-bed reactor at 100, 150, 200 and 300 °C by using simulated flue gas containing NO. The physical and chemical properties of the sorbents were analyzed by X-ray diffraction(XRD), Scanning electron microscope(SEM) and Fourier transform infrared(FTIR) and Inductively Coupled Plasma(ICP). The reactions mechanism has been discussed.Results showed that biomass–lignite chars impregnated with iron oxide had a high reactivity during catalytic reduction of NO. The highest catalytic performance was achieved at corncob to lignite ratio of 5:5. Synergetic effects between lignite and biomass during co-gasification were attributed to the potassium migration from biomass to lignite char which improved the efficiency of NO removal. Char implanted iron catalyst had a better dispersion of iron oxide compared with biomass and lignite implanted iron catalyst, resulting in improving the denitrification efficiency. Char impregnated iron catalyst promoted a great number of active sites and large active surface area leading to the NO conversion capacity increased by about 19 times. The catalysts had the highest denitrification efficiency at 300 °C, the denitrification efficiency at 100 ?, 150 ?, 200 ? decreased successively.With the addition of O2, O2 was chemisorbed on the surface of the active char, generating a large number of C[O], resulting in the formation of more active sites, which improve the sample denitrification efficiency. After the addition of water vapor, H2 O and C reacted to form CO, which promoted the active sites on char surface faster turnovered, making the denitrification efficiency reduced after the first increase. Among the three particle sizes of 0.075~0.125 mm, 0.5~0.9mm, 1~2mm, the smaller particle size of sorbent, the higher denitrification efficiency.