Modelling Inhibition Effects of Short-Chain Hydrocarbons on a Small-Pore Cu-Zeolite NH3-SCR Catalyst

NH3-SCR currently represents the leading technology for NOx abatement from lean exhaust gases, e.g. from diesel engines. Hydrocarbon (HC) slip onto the SCR catalyst can have a negative impact on its DeNOx performance. In order to better understand hydrocarbon poisoning, the influence of different light HCs on the catalytic activity of a small-pore Cu-zeolite has been investigated in a synthetic gas test rig. Based on these data and on further indications from the literature, an existing SCR kinetic model has been extended to represent major effects of light HCs on the behavior of zeolite SCR catalysts. The developed model is able to describe such effects in a simple but effective way.