Technical Challenges in the Integration of DPF and SCR Aftertreatment – Review from a Systems Perspe

Maruthi  Devarakonda, Pacific Northwest National Laboratory

Urea-SCR catalysts and diesel particulate filters (DPFs) are proven technologies in reducing the NOx and particulate emissions from diesel engines respectively. These are being considered as the technologies to meet the US 2010 emission standards of NOx (0.2 gm/bhp-hr) and particulate matter (PM – 0.01 gm/bhp-hr). To decrease the overall volume of the catalysts and the costs of the precious metals in the catalysts to burn the harmful pollutants (CO, HC, NOx and PM) in the exhaust, researchers have been investigating to develop an integrated NOx/PM aftertreatment system on a single substrate. One such technology involves the combination of urea-SCR and DPF catalytic converters for a heavy duty application. Though considerable knowledge is attained in understanding the catalyst components from a steady state perspective, more fundamental understanding is necessary through laboratory/engine testing to develop an integrated system. This talk presents a review on SCR and DPF catalysts individually, while looking at other technologies that were researched in the past for simultaneous NOx/PM control in diesel engines. Technical observations on the integrated system from a systems and modeling perspective will be summarized and recommendations for the future will be presented.

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