Removal of NO and fly ash over a carbon supported catalyst: Effects of fly ash concentration and operating time

Abstract

Abstract This study investigated the removal efficiency of NO and fly ash from flue gas over a Cu catalyst supported on modified activated carbon (AC) in a pilot-scale fluidized-bed catalytic reactor. The fly ash came from a coal-fired power plant was used in our experiment. The AC support was pretreated by either HNO 3 (AC–N), H 2 O 2 , H 2 SO 4 , or NaOH. The acidic concentrations in the four catalysts followed the order CuO/AC–N (0.174 mol g − 1 ) > CuO/AC–H (0.138 mol g − 1 ) > CuO/AC–S (0.103 mol g − 1 ) > CuO/AC–Na (0.009 mol g − 1 ). Good dispersion of nanoscale CuO particles was observed over the modified supports having a large total number of acidic sites. Moreover, the increase in the number of phenolic and carboxylic groups may increase the NO removal efficiency over modified CuO/AC catalysts. The results was also suggested that the total number of acidic groups decreased in the reduction of NO over the CuO/AC catalysts due to the adsorption of NH 3 on NO reduction. Simultaneous removal of NO and fly ash in flue gas under different fly ash concentrations and operating times was studied over the CuO/AC–N catalyst. When fly ash (1406–49,108 mg m − 3 ) was added in the flue gas, the removal efficiencies of NO and fly ash over Cu/AC–N were 58%–61% and 82%–86%, respectively. At an operating time of 240 min, the removal efficiency of fly ash was 76%, and the NO removal efficiency decreased slightly to 55%. The NO removal efficiency was inhibited slightly under high fly ash concentration and long operating time.