This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Investigation of Urea Deposits in Urea SCR Systems for Medium and Heavy Duty Trucks
Technical Paper
2010-01-1941
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
With increasing applications of urea SCR for NOx emission reduction, improving the system performance and durability has become a high priority. A typical urea SCR system includes a urea injector, injector housing, mixer, and appropriate pipe configurations to allow continuous urea injection into the exhaust stream and evaporation of urea solution into gaseous products. Continuous operation at various conditions with high NOx reduction is possible, but one problem that threatens the life and performance of these systems is urea deposit. When urea or its byproducts become deposited on the inner surfaces of the system including walls, mixers, injector housings and substrates it can create concerns of backpressure and material deteriorations. In addition, deposits as a waste of reagents can negatively affect engine operation, emissions performance and DEF economy.
Urea deposit behavior is explored in terms of heat transfer, pipe geometry, injector layout and mixing mechanisms. Two geometrical configurations of urea SCR systems are studied to evaluate heat transfer between urea and system and cooling of pipe wall where deposits can form. Multiple influencing factors such as wall temperature, urea injection rate, mixer and etc. are evaluated. Considerations on general urea test and mapping techniques are given. Necessary analytical predictions such as CFD spray modeling and theoretical formulas are performed and evaluated.
Recommended Content
Authors
Citation
Zheng, G., Fila, A., Kotrba, A., and Floyd, R., "Investigation of Urea Deposits in Urea SCR Systems for Medium and Heavy Duty Trucks," SAE Technical Paper 2010-01-1941, 2010, https://doi.org/10.4271/2010-01-1941.Also In
References
- BlueCat Adblue Material Safety Data Sheet. [MSDS] 2005
- Dong, H. Shuai, S. Wang, J. “Effect of Urea Thermal Decomposition on Diesel NOx-SCR Aftertreatment Systems,” SAE Technical Paper 2008-01-1544 2008 10.4271/2008-01-1544
- Zheng, G. Palmer, G. Salanta, G. Kotrba, A. “Mixer Development for Urea SCR Applications,” SAE Technical Paper 2009-01-2879 2009 10.4271/2009-01-2879
- Way, P. Viswanathan, K. Preethi, P. Gilb, A. et al. “SCR Performance Optimization Through Advancements in Aftertreatment Packaging,” SAE Technical Paper 2009-01-0633 2009 10.4271/2009-01-0633
- Rajadurai, S. “Improved NOx Reduction Using Wiremesh Thermolysis Mixer in Urea SCR System,” SAE Technical Paper 2008-01-2636 2008 10.4271/2008-01-2636
- Birkhold, F. Meingast, U. Wassermann, P. Deutschmann, O. “Analysis of the Injection of Urea-Water-Solution for Automotive SCR DeNOx-Systems: Modeling of Two Phase Flow and Spray/Wall-Interaction,” SAE Technical Paper 2006-01-0643 2006 10.4271/2006-01-0643
- Anspach, B. Brauer, J. Colson, J. Higgins, S. Schaber, P.M. Thielen, D. 2004 Thermal decomposition (pyrolysis) of urea in an open reaction vessel Thermochemica Acta 424 131 142