Abatement of NOx in exhaust gases.

摘要

Abatement of nitrogen oxides in an industrial exhaust gas is effected by reduction of the nitrogen oxides with ammonia in the presence of a catalyst that contains a crystalline zeolite having a silica to alumina ratio of at least 50 and a Constraint Index of 1 to 12. The catalyst may be virgin catalyst or catalyst previously used for the conversion of a hydrocarbon or for the conversion of methanol to hydrocarbon.