Control of NO and Hg0 emissions by SCR catalysts from coal-fired boiler.

CuO/γ-Al 2 O 3 and CuO–MnO 2 –Fe 2 O 3 /γ-Al 2 O 3 catalysts were synthesized by impregnation method. Their performances for selective catalytic reduction (SCR) were explored in a 200 MW coal-fired power plant boiler tail flue. The effects of catalyst amounts, NH 3 /NO molar ratios, abrasion resistance, catalyst regeneration and the catalytic efficiencies for Hg 0 oxidation were also discussed here. The optimum temperature range for the SCR of NO over fresh catalysts was 300 ~ 400 °C. In the optimum temperature range, the efficiencies of the two catalysts were over 80%, with a maximum efficiency of nearly 90% obtained at 350 °C. Reducing the catalyst amounts to half did not change the efficiency dramatically. The highest SCR activity was obtained with NH 3 /NO molar ratios ranging from 1.0 to 1.2. Abrasion resistance test indicates that the mechanical strength of the catalysts can bear the industrial scale and long-term erosion of fly ash. The activities of the catalysts remained constant during a 200 h test. Meanwhile, the catalysts were able to maintain excellent NO reduction efficiency after three times recycling. CuO/γ-Al 2 O 3 and CuO–MnO 2 –Fe 2 O 3 /γ-Al 2 O 3 achieved 40% and 80% Hg 0 oxidation efficiency, respectively. The present study provides a promising catalyst for NO and Hg 0 removal for coal-fired power plants. [ABSTRACT FROM AUTHOR]