Selective Catalytic Removal of NO from Stationary Sources

摘要

Research on selective catalytic removal of nitric oxide with ammonia to develop catalysts for use under conditions likely to produce flue gases was surveyed. The activity and selectivity of supported vanadium, tungsten, and iron oxide catalysts were studied in a plug-flow and a mixed-flow reactor on a laboratory scale between 370 and 670 K. The effects of the NO/NH3 ratio, space-velocity and oxygen on the reduction reactions, and effects of catalysts on ammonia and sulfur dioxide oxidation were investigated. The catalysts were characterized by conventional techniques. All the catalysts showed relatively high NO conversion. Data show that the NO/NH3 reaction in the presence of oxygen below 575 K is according to the formula 4 NO + 4 NH3 + O2 yields 4N2 + 6 H2O. Selectivity decreases above 625 K because of NH3 oxidation. The rate of the NO/NH3 reaction on the catalysts under dilute gas conditions is markedly increased by the addition of 1% oxygen.