| 摘要 |
A catalyst system for the selective reduction of gaseous NOx in the presence of excess oxygen, having a copper-containing ZSM5 zeolite to which a NOx-containing gas is exposed, and means for introducing a metered volume of finely dispersed, water soluble, oxygen-containing organic compound (alcohol, aldehyde, ketone, ether) into the NOx-containing gas prior to exposure to the Cu-ZSM5 zeolite. Also, a method of treating automotive exhaust gas emissions, having an excess of oxygen, by the steps of: (a) introducing a water soluble, oxygenated organic compound (steam/oxygenate mixture) into the exhaust gas emissions as a reductant and at a location closely adjacent the source of the exhaust gas generation (in an appropriate amount with respect to the NOx); (b) substantially immediately exposing the reductant/emission mixture to a transition metal-exchanged high silica ZSM5 zeolite (SiO2/A12O3 of between 10-50) catalyst at a space velocity in the range of 20-80 K hr-l; and (c) sequentially exposing the effluent of such zeolite catalyst to an oxidation catalyst. 6843L |
