Catalytic Reduction of NOx in Diesel Exhaust

Catalytic reduction of NOx from diesel engine exhaust by the addition of saturated hydrocarbons, or diesel fuel has been demonstrated using a newly developed copper containing catalyst system.

Fundamental interactions between NOx, oxygen and hydrocarbons over the copper based catalysts have been studied in relation to NOx reduction by hydrocarbon additions and in relation to hydrocarbon oxidation. The different NOx reduction characteristics of the various hydrocarbons, were revealed. Based on this work, the catalyst system and the hydrocarbon spray system have been designed to effectively reduce NOx over a wide exhaust temperature range.

In laboratory experiments, the newly developed catalyst system combined with a diesel fuel or heavy saturated hydrocarbon spray system effectively reduces NOx by 20%-30% over an exhaust temperature range of 350°C - 550°C.