Selective Catalytic Reduction of Nitric Oxide over Copper Oxide and Cerium Oxide Catalysts

摘要

The selective catalytic reduction of NO with hydrocarbons in an oxygen-containing simulated flue gashas been investigated for a series of copper oxide and cerium oxide catalysts. The activity of aluminasupported catalysts for the reduction of NO by propane has been investigated at temperatures of 600-775 K. Methane was also examined as a reductant, and neither copper oxide/alumina nor ceriumoxide/alumina is active for selective catalytic reduction of NOx with methane up to 775 K. Thepresence of sulfates on the catalyst and the effects of water vapor and/or sulfur dioxide addition to thesimulated flue gas have been examined for both the SCR of NOx by propane and direct decompositionof NO. Both copper sulfate on alumina and cerium sulfate on alumina are substantially less active forpropane SCR than the respective oxides. Both catalyst types are reversibly inhibited by the presence ofwater vapor. The effect of sulfur dioxide in the gas stream appears to be only mildly inhibiting, but sincethe optimum temperature range for propane reduction of NO is the same as the optimum temperaturerange for SO_2 adsorption by copper oxide, the CuO/Al_2O_3 sorbent/catalyst will quickly becomesulfated, even at low flue gas SO2 concentrations.