This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Experimental Investigation of Novel Ammonia Mixer Designs for SCR Systems
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 3, 2018 by SAE International in United States
Annotation ability available
Meeting Euro 6d NOx emission regulations lower than 80 mg/km for light duty diesel (60 mg/km gasoline) vehicles remains a challenge, especially during cold-start tests at which the selective catalyst reduction (SCR) system does not work because of low exhaust gas temperatures (light-off temperature around 200 °C). While several exhaust aftertreatment system (EATS) designs are suggested in literature, solutions with gaseous ammonia injections seem to be an efficient and cost-effective way to enhance the NOx abatement at low temperature. Compared to standard SCR systems using urea water solution (UWS) injection, gaseous NH3 systems allow an earlier injection, prevent deposit formation and increase the NH3 content density. However non-uniform ammonia mixture distribution upstream of the SCR catalyst remains an issue. These exhaust gas/ NH3 inhomogeneities lead to a non-optimal NOx reduction performance, resulting in higher than expected NOx emissions and/or ammonia slip. Thus, efficient mixers upstream of the SCR are crucial for the overall EATS performance. In the experimental study reported in this article, planar laser induced fluorescence (PLIF) is used to quantify mixing performance of four novel CFD optimized static mixers in an optically accessible flow bench. The variation of boundary conditions and the change of exhaust line configurations (e.g. w/wo DOC upstream, w/wo DPF downstream) show a major effect on the mixing process and subsequently the homogeneity of the ammonia-exhaust gas mixture (for example: drop in uniformity index from UI = 0.95 to UI = 0.60 for a blade mixer design). This points out the need to purposefully design and optimize static mixers for a specific exhaust line configuration.
CitationSchiffmann, P., Lecompte, M., and Laget, O., "Experimental Investigation of Novel Ammonia Mixer Designs for SCR Systems," SAE Technical Paper 2018-01-0343, 2018, https://doi.org/10.4271/2018-01-0343.
- Balland, J.,Parmentier, M., andSchmitt, J., “Control of a Combined SCR on Filter and Under-Floor SCR System for Low Emission Passenger Cars,” SAE International Journal of Engines 7(3), 2014, doi:10.4271/2014-01-1522.
- Sharp, C.,Webb, C.,Yoon, S.,Carter, M. et al., “Achieving Ultra Low NOX Emissions Levels with a 2017 Heavy-Duty on- Highway TC Diesel Engine - Comparison of Advanced Technology Approaches,” SAE International Journal of Engines 10(4), 2017, doi:10.4271/2017-01-0956.
- Fulks, G.,Fisher, G.,Rahmoeller, K.,Wu, M. et al., “A Review of Solid Materials as Alternative Ammonia Sources for Lean NOx Reduction with SCR,” SAE Technical Paper 2009-01-0907, 2009, doi:10.4271/2009-01-0907.
- Paul, E. L.,Atiemo-Obeng, V. A.,Kresta, S. M., “Handbook of Industrial Mixing: Science and Practice” ISBN: 978-0-471-26919-9
- Thakur, R.K.,Vial, C.,Nigam, K.D.P.,Nauman, E.B. et al., “Static Mixers in the Process Industries-a Review,” Chemical Engineering Research and Design 81(7):787-826, 2003ISSN 0263-8762, http://dx.doi.org/10.1205/026387603322302968.
- Lecompte, M.,Raux, S., andFrobert, A., “Experimental Characterization of SCR DeNOx-Systems: Visualization of Urea-Water-Solution and Exhaust Gas Mixture,” SAE Technical Paper 2014-01-1524, 2014, doi:10.4271/2014-01-1524.
- Kowatari, T.,Hamada, Y.,Amou, K.,Hamada, I. et al., “A Study of a New Aftertreatment System (1): A New Dosing Device for Enhancing Low Temperature Performance of Urea-SCR,” SAE Technical Paper 2006-01-0642, 2006, doi:10.4271/2006-01-0642.
- Nishioka, A.,Amou, K.,Yokota, H., andMurakami, T., “AUrea-Dosing DeviceFor Enhancing Low-Temperature Performance by Active-Ammonia Production in an SCR System,” SAE Technical Paper 2008-01-1026, 2008, doi:10.4271/2008-01-1026.
- Tenneco Automotive Operating, “Exhaust Gas Additive/Treatment System and Mixer for Use Therein,” U.S. Patent, Pub.No. US2009266064A, Oct 29, 2009
- Audi Ag, “Statischer Mischer Fuer Eine Abgasanlage Einer Brennkraftmaschine,” German Patent, Pub.No. DE102007012790B4, Sep 18, 2008
- Bosch Corp, “exhaust Gas Purification Apparatus for Internal Combustion Engine,” U.S. Patent, Pub. No. US2010083643A, Sept. 18, 2008
- IAV Gmbh, “Static Mixer Melangeur Statique Statischer Mischer,” German patent. Pub.No. WO2015DE100182, Nov 12, 2015
- Peugeot Citroen Automobiles SA, “Ligne D'echappement Pour Moteur A Combustion, Dotee D'un Organe De Guidage D'un Melange Entre Des Gaz D'echappement Et Un Agent Reducteur,” French Patent, Pub. No. FR2971546B, Aug 17, 2012
- Peugeot Citroen Automobiles SA, “Device for Mixing a Main Gas Flow and a Secondary Gas Flow Dispositif Pour Le Melange Entre Un Flux Gazeux Principal Et Un Flux Gazeux Auxiliaire,” French Patent, Pub. No. WO11086259A1, Jul 21, 2011
- Liebherr Machines Bulle SA, “Vorrichtung Zur Abgasnachbehandlung Einer Brennkraftmaschine Mit Einem Abgasstromverwirbler. Device for an Internal Combustion Engine Aftertreatment with a Abgasstromverwirbler,” Swiss Patent, Pub. No. CH710416A, May 31, 2016
- Gadelius KK, “Mixing Apparatus,” Japanese patent, Pub. No. JP61057225A, Mar 24, 1986
- Hitachi Ltd, “Apparatus for Mixing Gas,” Japanese Patent, Pub. No. JP2008049306A, Mar 6, 2008
- Kleen Air Systems Inc, “Ammonia Injection in Nox Control,” U.S. Patent, Pub. No. US5992141A, Nov 30, 1999
- Alano, E.,Jean, E.,Perrot, Y.,Brunel, J. et al., “Compact SCR for Passenger Cars,” SAE Technical Paper 2011-01-1318, 2011, doi:10.4271/2011-01-1318.
- Zheng, G.,Palmer, G.,Salanta, G., andKotrba, A., “Mixer Development for Urea SCR Applications,” SAE Technical Paper 2009-01-2879, 2009, doi:10.4271/2009-01-2879.
- Padula, G.,Schiffmann, P.,Lecompte, M., andLaget, O., “Computational Fluid Dynamics Study of Gaseous Ammonia Mixing in an Exhaust Pipe Using Static Mixers,” SAE International Journal of Engines 10(4), 2017, doi:10.4271/2017-01-1018.
- Schiffmann P.,Laget O.,Lecompte M.; “Gaseous Ammonia Mixer Optimization for SCR Systems: A Combined Experimental and Numerical Approach,” SIA Powertrain; 16 & 17 May, 2018 - Rouen, Normandy - France.
- Cordier M.,Lecompte M.,Raux S.,Ricordeau V.,Chérel J.; “Optical characterization of Urea Water Solution along an exhaust pipe”; SIA Powertrain; Rouen 1.& 2. June 2016
- Winter, René. Fluorescent Tracers for Air-Sided Concentration Profile Measurements at the Air-Water Interface. Dissertation, 2011.
- Hole, O.M., “Measuring Ammonia: Development and Application of Measurement Techniques for the Detection of Ammonia,” Lund Report on Combustion Physics, 2013.