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US 10,258,972 B2Granted
Catalyzed SCR filter and emission treatment system
AssigneeBASF SE
InventorsJoseph A. Patchett, Joseph C. Dettling, Elizabeth A. Przybylski
Life of this patent
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Abstract
Provided is a catalyst article for simultaneously remediating the nitrogen oxides (NOx), particulate matter, and gaseous hydrocarbons present in diesel engine exhaust streams. The catalyst article has a soot filter coated with a material effective in the Selective Catalytic Reduction (SCR) of NOx by a reductant, e.g., ammonia.
Claims13
An emission treatment system for treatment of an exhaust stream comprising NOx and particulate matter, the emission treatment system comprising:
- (a) a diesel oxidation catalyst comprising a platinum group metal dispersed on a refractory oxide support positioned downstream from a diesel engine;
- (b) an injector in fluid communication with and downstream of the oxidation catalyst, wherein the injector periodically meters ammonia or an ammonia precursor into the exhaust stream;
- and
- (c) a catalyst article in fluid communication with and downstream of the injector, the catalyst article comprising a wall flow monolith and a catalytic material contained within the wall flow monolith, wherein the wall flow monolith has a wall porosity of at least 50% and comprises a plurality of longitudinally extending passages formed by longitudinally extending porous walls bounding and defining said passages, wherein the passages comprise inlet passages having an open inlet end and a closed outlet end, and outlet passages having a closed inlet end and an open outlet end, and wherein the catalytic material comprises a zeolite and a base metal selected from copper and iron present in an amount of from about 0.1 to 30 percent by weight of the total weight of base metal plus zeolite, the zeolite having pores connected in three dimensions and a silica to alumina ratio of at least about 10, the wall flow monolith having integrated NOx and particulate removal efficiency when exposed to diesel engine exhaust and ammonia or an ammonia precursor.
1 more element
A method for treating emissions produced in an exhaust stream from a diesel engine comprising NOx and particulate matter, the method comprising:
- (a) passing the exhaust stream through a diesel oxidation catalyst comprising a platinum group metal dispersed on a refractory oxide support such that a portion of NO is oxidized to NO2 to provide an NO2-enriched exhaust stream;
- (b) metering, at periodic intervals, ammonia or an ammonia precursor into the NO1-enriched exhaust stream using an injector in fluid communication with and downstream of the oxidation catalyst:
- and
- (c) subsequently passing the exhaust stream treated with ammonia or an ammonia precursor through a catalyst article such that particulate matter is filtered and a substantial portion of NOx is reduced to N2, the catalyst article comprising a wall flow monolith and a catalytic material contained within the wall flow monolith, wherein the wall flow monolith has a wall porosity of at least 50% and comprises a plurality of longitudinally extending passages formed by longitudinally extending porous wails bounding and defining said passages, wherein the passages comprise inlet passages having an open inlet end and a closed outlet end, and outlet passages having a closed inlet end and an open outlet end, and wherein the catalytic material comprises a zeolite and a base metal selected from copper and iron present in an amount of from about 0.1 to 30 percent by weight of the total weight of base metal plus zeolite, the zeolite. having pores connected in three dimensions and a silica to alumina ratio of at least about 10, the wall flow monolith having integrated NOx and particulate removal efficiency when exposed to diesel engine exhaust and ammonia or an ammonia precursor.
1 more element
Dependencies are inferred from the claim text.