Method of Forming a Catalyzed SCR Filter
AssigneeBASF Catalysts LLC
InventorsJoseph A. Patchett, Joseph C. Dettling, Elizabeth A. Przybylski
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Abstract
Provided is an emission treatment system and method for simultaneously remediating the nitrogen oxides (NOx), particulate matter, and gaseous hydrocarbons present in diesel engine exhaust streams. The emission treatment system has an oxidation catalyst upstream of a soot filter coated with a material effective in the Selective Catalytic Reduction (SCR) of NOx by a reductant, e.g., ammonia. Also provided is a method for disposing an SCR catalyst composition on a wall flow monolith that provides adequate catalyst loading, but does not result in unsuitable back pressures in the exhaust.
Claims25
A method for disposing an SCR catalyst composition on a wall flow monolith, 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 method comprising:
- immersing the wall flow monolith in an aqueous slurry comprising the SCR catalyst composition from a first direction to deposit the SCR catalyst composition on the inlet passages;
- immersing the wall flow monolith in an aqueous slurry comprising the SCR catalyst composition from a second direction, opposite the first direction, to deposit the SCR catalyst composition on the outlet passages;
- and
- drying and calcining the coated wall flow monolith.
A method for disposing an SCR catalyst composition on a wall flow monolith, 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 method comprising:
- depositing a layer of the SCR catalyst composition on the inlet passages that permeates the walls at a concentration of up to 2.4 g/in3;
- depositing a layer of SCR catalyst composition on the outlet passages that permeates the walls at a concentration of up to 2.4 g/in3;
- drying and calcining the coated wall flow monolith.
Dependencies are inferred from the claim text.