Catalyzed SCR Filter And Emission Treatment Method

摘要

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.

主权项

1. A method for treating emissions produced in an exhaust stream from a diesel engine comprising NOx and particulate matter, the method comprising:
adding ammonia or an ammonia precursor into the exhaust stream and passing the exhaust stream containing the ammonia through a wall flow monolith wherein particulate matter is filtered and a substantial portion of NOx is reduced to N2; wherein the wall flow monolith has a plurality of longitudinally extending passages formed by longitudinally extending 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, the wall flow monolith having a porosity of from 60% to 75% and an average pore size of from 10 to 30 microns; wherein the wall flow monolith comprises a washcoat of SCR catalyst composition that permeates the walls, the SCR catalyst composition comprising a zeolite and base metal component selected from one or more of a copper and iron component, the washcoat permeating the walls at a loading up to 2.4 g/in3, the wall flow monolith providing integrated NOx and particulate removal efficiency when the exhaust stream comprising NOx and particulate matter passes through the wall flow monolith such that particulate matter is trapped on the wall flow monolith.