| 摘要 |
Treating diesel motor exhaust gas containing nitric oxide and hydrocarbons, comprises: (a) adding ammonia or a compound that can be decomposed to ammonia in the exhaust gas stream containing nitric oxide and hydrocarbons; (b) leading over e.g. nitric oxide or an exhaust stream containing the compound over a first inflow side arranged selective catalytic reduction (SCR) catalyst, and at least partially oxidizing hydrocarbons contained in the exhaust gas; and (c) leading over exhaust gas resulting from step (b) over a second, downstream arranged SCR catalyst, and storing the excessive ammonia. Treating diesel motor exhaust gas containing nitric oxide and hydrocarbons, comprises: (a) adding ammonia or a compound that can be decomposed to ammonia from a source that does not belong to the exhaust gas system in the exhaust gas stream containing nitric oxide and hydrocarbons; (b) leading over the nitric oxide, hydrocarbons and ammonia, or an exhaust gas stream containing the compound over a first inflow side arranged SCR catalyst, which catalyzes the comproportionation of the nitric oxide with ammonia at 300-500[deg] C, and simultaneously at least partially oxidizing hydrocarbons contained in the exhaust gas; and (c) leading over the exhaust gas resulting from the step (b) over a second, downstream arranged SCR catalyst, which catalyzes the comproportionation of the nitric oxide with ammonia at 150-400[deg] C, and simultaneously storing the excessive ammonia. An independent claim is included for an exhaust gas purification device for reducing nitric oxide in the meager exhaust gas from combustion engines, comprising a device (1) for the addition of ammonia or the compound in the nitric oxide containing exhaust gas stream from a source (2) that does not belong to the exhaust gas system, and the source for ammonia or the compound, a first SCR catalyst (3) and neither vanadium- nor zeolite-compounds, and a second, vanadium-free SCR catalyst (4) and a copper replaced zeolite compound. |
