systems for treating exhaust gas and exhaust gas, and method for treating an exhaust gas stream.

摘要

exhaust gas treatment systems for treating a nox containing engine exhaust gas stream are described. the exhaust gas treatment system comprises an engine, a catalyst system comprising a catalytic selective reduction article comprising two zones, an upstream zone comprising first iron-promoted molecular sieves and a downstream zone comprising second sieves promoted molecular compounds. The catalyst system is effective for reducing high levels of nox in the exhaust gas stream. Also disclosed are methods for treating engine exhaust gas streams, which comprises treating engine exhaust gas streams containing high nox levels with catalyst systems that include catalytic selective reduction articles having two zones.