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VWT - SCR Catalyst to Meet BS-IV Emission Standards and Beyond
ISSN: 0148-7191, e-ISSN: 2688-3627
Published January 09, 2013 by The Automotive Research Association of India in India
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Technologies for exhaust aftertreatment of diesel engines are driven by emission standards and Selective Catalytic Reduction (SCR) will play a key role in complying with the requirements, particularly for the heavy duty vehicles. Amongst the variety of catalysts for the SCR reaction, the Vanadium-Tungsten-Titanium-Based (VWT) system is preferred over the base metal doped zeolite because of the established advantages of wide temperature window, robust and durable performance and resistance to sulfur exposure.
While the basic chemical reactions involved in ammonia-SCR are well known, the challenge lies in identifying the right combination of substrate and wash coat formulation to meet with customer specific requirements. An insight into the relevant materials properties of the substrates as well as the bulk surface properties of the wash coat such as its ammonia storage capacity, V2O5 dispersion and stability are important.
Typically the VWT-SCR technology is operated upto a upper limit of 450°C. This paper reports the optimization of a VWT formulation which can be used upto > 500°C. The influence of different operating parameters such as NO2/NOx ratio, NH3/NOx ratio, oxygen content, space velocity has been studied. In addition, the suppression of the undesirable formation of N2O on an optimized catalyst formulation is also reported. Effects of poisonous elements such as Na, K, Zn, etc on the SCR performance are also studied. The database generated over a wide range of operating parameters forms the basis to evolve the design criteria for offering customer specific solutions with demonstrated performance and durability.
CitationNarkhede, V., Kumar, D., Cursetji, R., Siddiquie, T. et al., "VWT - SCR Catalyst to Meet BS-IV Emission Standards and Beyond," SAE Technical Paper 2013-26-0056, 2013, https://doi.org/10.4271/2013-26-0056.
- EPA and NHTSA Greenhouse Gas Emissions Standards and Fuel efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles 76 2011 57106 www.gpo.gov/fdsys/pkg/fr-2011-09-15/pdf/2011-20740.pdf
- Gekas Ioannis et.al. Urea-SCR Catalyst System Selection for Fuel and PM Optimized Engines and a Demonstration of a Novel Urea Injection System SAE Paper No. 0289-01-2002 2002 10.4271/0289-01-2002
- Majewski W.A. Selective Catalytic Reduction Ecopoint Inc. DieselNet Technology Guide
- Long , R.Q. , Chang , M.T. , Yang , R.T. Enhancement of activities by sulfation on Fe-exchanged TiO 2 -pillared clay for selective catalytic reduction of NO by ammonia Appl. Catal. B Environ. 33 97 107 2001
- Kompio P. G. W. A. , Brückner A. , Hipler F. , Auer G. , Löffler L. , Grünert W. A new view on the relations between tungsten and vanadium in V 2 O 5 -WO 3 /TiO 2 catalysts for the selective reduction of NO with NH 3 Journal of Catalysis 286 237 247 2012
- Chen J.P. , Yang R.T. Selective catalytic reduction of NO with NH 3 on SO 2 =TiO 2 superacid catalyst J. Catal. 139 277 288 1993
- Cejka J. , Corma A. , Zones S. Zeolites and Catalysis: Synthesis, Reactions and Applications 1 WILEY-VCH Verlag GmbH and Co. KGaA Weinheim, Germany 2010
- Nicosia D. , Nicosia D. , Elsener M. , Kröcher O. , Jansohn P. Basic investigation of the chemical deactivation of V 2 O 5 /WO 3 -TiO 2 SCR catalysts by potassium, calcium, and phosphate Topics in Catalysis 42 333 336 2007
- Kamasamudram K. , Currier N.W. , Chen X. , and Yezerets A. Overview of the practically important behaviors of zeolite-based urea-SCR catalysts, using compact experimental protocol Catalysis Today 151 212 222 2010
- Schmieg S.J. et al Thermal durability of Cu-CHA NH 3 -SCR catalysts for diesel NOx reduction Catalysis Today 184 252 261 2012
- Kamasamudram , K. , Henry , C. , Currier , N. , and Yezerets , A. N 2 O Formation and Mitigation in Diesel Aftertreatment Systems SAE Int. J. Engines 5 2 688 698 2012 10.4271/2012-01-1085