| 摘要 |
PURPOSE:To obtain a catalyst excellent in heat resistance, having high activity at a low temp. and used for removing NOx with hydrocarbons as a reducing agent in an oxidizing atomsphere cont,g. excess oxygen. CONSTITUTION:Three kinds of catalysts respectively consisting of an alumina- based oxide, that is, Rh/Mg-Al2O3, Co/Mg-Al2O3 and Ag/Mg-Al2O3 are used. A catalyst bed 4 in a reaction tube 3 is packed. with Co/Mg-Al2O3 as a 1st layer 1 and Rh/Mg-Al2O3 as a 2nd layer 2 to form a catalyst bed having a two-layered structure. Since the two kinds of catalysts are laminated, a wider effective reaction temp. region can be ensured and a directional property can be imparted to a flow of gas. |
