Research On The Catalystic Oxidation Of Hg~0 By Modified SCR Catalysts And Stabliabiliztion In Coal- Fired Power Plants

At present, the coal-fired power plant aren’t equippted with pollution control device for mercury,even setting aside a separate space. So it is economical and feasible to use the existing devices to control mercury emission. Firstly, these catalysts with different V2O5 content or a second additive modification were prepared on the existing commercial SCR catalyst. And the CeO2 modified SCR catalyst was elected among all prepared catalysts in the simulated flue gas. The results showed the catalytic activity of the catalyst was remarkably increased after the CeO2 modification, and the highest efficiency was obtained from the modified SCR catalyst with 9% Ce loading,40% higher than that of the non-modified SCR catalyst. Besides, the denitration efficiency of SCR catalyst had no effect after doping CeO2.Secondly, aiming at the characteristics of Hg2+ in wet flue gas desulfurization systems due to its Hg2+ reduction, reduction re-emission mechanism of Hg2+ was studied in the simulated WFGD slurry. The effects of several experimental parameters on the reduction were studied, including temperature, initial pH and concentrations of SO32-, et al. In addition, three kinds of precipitants were investigated in the simulated WFGD slurry to prevent the Hg2+ reduction. The results indicated that controlling appropriately temperature, initial pH and concentrations of SO32-, as well as the addition of precipitants, could prevent Hg2+ re-emission.Hg2+ may be reduced Hg0 under a lot of reducing substances existence conditions in desulfurized wastewater, and cause secondary environmental pollution. Finally, the stabilization of mercury was studied in simulation desulfurization wastewater. The following conclusions can be drawed by analyzing the effect of four heavy metal:at the same reaction condition, the DTCR is affected less than the other by the factors, for instance the pH, temperature, et al, whose removal efficiency can be reached to about 80%. Consequently, in response to these coal-fired power plant mercury removal system key issues, it is of great theoretical and practical significance to develop correlation studies.