System for NOx reduction in exhaust gases

摘要

Selective catalytic reduction of NOx in combustion gases, especially from diesel engines, utilizes a system incorporating an oxidation catalyst to convert at least a portion of NO to NO2, a particulate filter downstream of the oxidation catalyst, a source of reductant such as NH3 or urea for injection downstream of the particulate filter, and an SCR catalyst located downstream of the point of injection of the reductant. Considerable improvements in NOx conversion are observed.