Catalyst – solid sorbent – or support therefor: product or process – Zeolite or clay – including gallium analogs
Reexamination Certificate
2006-08-22
2006-08-22
Langel, Wayne A. (Department: 1754)
Catalyst, solid sorbent, or support therefor: product or process
Zeolite or clay, including gallium analogs
C423S232000, C423S213200, C423S213500, C423S239200, C502S064000, C502S065000, C502S066000, C502S071000, C502S073000, C502S074000, C502S077000, C502S078000, C502S079000
Reexamination Certificate
active
07094722
ABSTRACT:
The activity and durability of a zeolite lean-bum NOx catalyst can be increased by loading metal cations on the outer surface of the zeolite. However, the metal loadings can also oxidize sulfur dioxide to cause sulfate formation in the exhaust. The present invention is a method of suppressing sulfate formation in an exhaust purification system including a NOxcatalyst. The NOxcatalyst includes a zeolite loaded with at least one metal. The metal is selected from among an alkali metal, an alkaline earth metal, a lanthanide metal, a noble metal, and a transition metal. In order to suppress sulfate formation, at least a portion of the loaded metal is complexed with at least one of sulfate, phosphate, and carbonate.
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Balmer-Millar Mari Lou
Panov Alexander G.
Park Paul W.
Caterpillar Inc.
Langel Wayne A.
Liell & McNeil
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