| 摘要 |
Catalytic articles, systems and methods for treating exhaust gas streams are described. A catalytic article comprising a wall flow filter having gas permeable walls, a hydrolysis catalyst, an optional soot oxidation catalyst, a selective catalytic reduction catalyst permeating the walls, an ammonia oxidation catalyst and an oxidation catalyst to oxidize CO and hydrocarbons is described. Methods of treating exhaust gas streams comprising soot, an ammonia precursor such as urea, ammonia, NOx, CO and hydrocarbons are also provided. |
| 主权项 |
1. A catalytic article to remove emissions from a gas stream containing soot, ammonia, an ammonia precursor, NOx, CO and hydrocarbons, the article comprising:
a wall-flow filter for trapping soot in the gas stream, the filter having an inlet end and an outlet end defining an overall length, gas permeable walls having a thickness formed into a plurality of axially extending inlet channels and outlet channels, each inlet channel having inlet walls, an open inlet end and an outlet plug at the outlet end, each outlet channel having outlet walls, inlet plugs at the inlet end and an open outlet end, with each inlet channel having adjacent outlet channels; a selective catalytic reduction catalyst permeating the gas permeable walls, the selective catalytic reduction catalyst promoting the conversion of NOx in the gas stream to N2 in the presence of excess oxygen; an ammonia oxidation catalyst coating a length of the outlet walls of the outlet channels that promotes the selective oxidation of ammonia to N2 in the gas stream; and an oxidation catalyst coated on a portion of the outlet walls of the outlet channels extending from the outlet end toward the inlet end that promotes the oxidation of CO and hydrocarbons to CO2, wherein there is substantially no overlap of the oxidation catalyst on the ammonia catalyst. |
