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Investigation of Urea-SCR at Low Temperatures

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Abstract

This paper addresses the NOx removal from diesel exhaust by using urea-SCR technique with focus on critical operating conditions, particularly low temperatures. The investigations were performed on a special laboratory test bench enabling the supply of aqueous urea solution (“AdBlue”) or gaseous NH3 to practical model exhaust. The SCR tests were made with a commercial V2O5/WO3/TiO2 honeycomb catalyst showing very similar performance between 250 and 400 °C when dosing AdBlue and NH3. However, below 200 °C the activity of urea-SCR was clearly lower than that of NH3-SCR due to incomplete conversion of urea and formation of deposits covering the reactor wall. ATR-IR analyses evidenced that these residues consist of urea as well as cyanuric acid originated from side-reactions of isocyanic acid. Furthermore, ramping the temperature upon urea-SCR forced the deposits towards consecutive reactions mainly resulting in cyanuric acid. Consequently, our study provides insights into the dynamic decomposition behavior or urea-related residues relevant for reliable SCR process in diesel exhaust.

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Authors and Affiliations

  1. Institute of Energy Process Engineering and Chemical Engineering, Chair of Reaction Engineering, Technical University of Freiberg, Fuchsmuehlenweg 9, 09596, Freiberg, Germany

    A. Roppertz, S. Füger & S. Kureti

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  1. A. Roppertz
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  2. S. Füger
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  3. S. Kureti
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Correspondence to S. Kureti.

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Roppertz, A., Füger, S. & Kureti, S. Investigation of Urea-SCR at Low Temperatures. Top Catal 60, 199–203 (2017). https://doi.org/10.1007/s11244-016-0597-8

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  • DOI: https://doi.org/10.1007/s11244-016-0597-8

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