METHOD AND SYSTEM FOR THE COMBINATION OF NON-THERMAL PLASMA AND METAL/METAL OXIDE DOPED Y-ALUMINA CATALYSTS FOR DIESEL ENGINE EXHAUST AFTERTREATMENT SYSTEM

摘要

The present disclosure pertains to a system and method for treatment of oxygen rich exhaust and more specifically to a method and system that combines non-thermal plasma with a metal doped .gamma.-alumina catalyst. Current catalyst systems for the treatment of oxygen rich exhaust are capable of achieving only approximately 7 to 12% NO x reduction as a passive system and only 25-40% reduction when a supplemental hydrocarbon reluctant is injected into the exhaust stream. It has been found that treatment of an oxygen rich exhaust initially with a non-thermal plasma and followed by subsequent treatment with a metal doped .gamma.- alumina prepared by the sol gel method is capable of increasing the NO x reduction to a level of approximately 90% in the absence of SO2 and 80% in the presence of 20 ppm of SO2. Especially useful metals have been found to be indium, gallium, and tin.