| NOx (nitrogen oxides) are the main pollutants in the atmosphere, its sources include automobile exhaust and flue gas of power plant, and 90%-95% of which is NO. Wet denitration refers to partial catalytic oxidation NO to NO2 first, and then liquid-phase absorption by using of mixture of N2O3. Wet denitration have features of high efficiency, low reaction temperature and does not produce secondary pollutant such as NH3, compared to the existing DeNOx technology of SCR , is a promising method of denitrification. However, due to concentration of NO in flue gas are usually higher and more stable at room temperature and not easily oxidized, therefore, catalysts which have highly efficient and stable NO oxidation are focus points of this article.γ-aluminium oxide doped with Mn- and Fe- were prepared by incipient wetness impregnation. Effects of the metal loading, molar ratios of Mn and Fe and different base neutralization on NO conversion were investigated in a tubular reactor. The results show that Mn-Fe/γ-Al2O3 with 20% loading, metal molar ratio of 1 and tetramethy-lammonium hydroxide for acid-base adjusting got the highest activity at about 66% in the temperature of 300℃, inlet concentration of NO is 300ppm, concentration of O2 is 5% and GHSV is 12000h-1. The phase structure and surface morphology of the mixed oxides were investigated by XRD and SEM, and found that crystal phase of the sample gradually separated, diffraction peaks of Fe2O3 and MnO2 increasingly acute as the loading increases, in other word, active components was permeating into the carrier pores. In addition, samples neutralized by organic base would form high surface dispersity and amorphous state crystal, which increased the NO conversion.A series of Ce-Co-Mn-O mixed oxide catalysts were prepared by the citric acid sol-gel method. The influence of synthetic conditions (citric acid content, Co/Mn, Ce content and calcination temperature), operating conditions (reaction temperature, inlet concentration of NO, concentr- ation of O2 and space velocity) and SO2 on NO catalytic oxidation activity were investigated. The results show that citric acid and metal ion ratio of 1.5, Ce: Co: Mn molar ratio of 2:1:3, catalyst calcined at 450℃, the entrance of NO equal to 300ppm, O2 equal to 5% and space velocity of 12000h-1 had the best catalytic activity(close to 72%). However, when catalyst calcined at 750℃, it got the worst catalytic effect. Results of XRD and BET showed that the effect is due to the small specific surface area and the production of spinel crystals after high-temperature calcination. Images of SEM can be seen a large number of honeycomb- like porous structure existed in the catalyst. EDAX elemental analysis shows that molar ratio of CeCoMnO is 2:1:3:7.5.Through elementary reactions of NO catalytic oxidation in plug-flow tubular reactor, intrinsic kinetic model of Rideal-Elay mechanism and Langmuir-Hinshelwood mechanism were investigated. It is derived the conversion rate equation in the ideal conditions and real gas condition. The influence of different initial O2 concentration on thermal equilibrium conversion was also studied. Without taking into account reverse reaction of NO2, established kinetic model of Ce-Co-Mn-O complex oxides, and using the Arrhenius equation to derive the overall reaction rate equation.Investigated the effect of NOx removal when using deionized water, (NH4)2CO3, sodium humate, NH3·H2O and Na2CO3 for the absorbent material and analysed the possible chemical reactions. The results show that with (NH4)2CO3 and the NH3·H2O as the absorption liquid, NOx removal got the highest efficiency. When concentration of NO2 had a conversion of 53.2%, the removal efficiency climbed up to 80%. In addition, experiments also demonstrated the NO's strong polarity and difficult to dissolve in water, therefore, it's more difficult to absorption of NO than the NO2.
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