Effect of H2O on NH3 Storage in an Fe-SCR catalyst
Michael Smith, University of Michigan
Concepts for combinations of multiple types of catalysts are becoming more common in catalyst systems. One combination is an LNT – SCR combination where the LNT will release NH3 during a regeneration to be used by the SCR catalyst for further NOx reduction. This involves rich lean cycling of the exhaust stream which can vary the H2O/CO2 level in the exhaust from 6% to 15%. Throughout literature it has been stated and established that H2O has adverse effects on NH3 storage on an SCR catalyst. This is especially problematic because the less NH3 stored on the catalyst the less NOx can be converted. This study will examine the how different H2O/CO2 levels will effect NH3 storage on an Fe-SCR catalyst, and a global modeling approach to capture these effects.