Influence of the Backpressure on Urea Sprays Generated by an Air-Blast Atomizer for Large-Scale SCR-Applications
Published January 15, 2019 by SAE International in United States
Downloadable datasets for this paper availableAnnotation of this paper is available
In 2016, the latest step of emission standards for marine ships came into operation. As the emission limit for nitric oxides has decreased to approximately 25% of the former values, selective catalytic reduction (SCR) will play an important role to fulfil those limits. SCR is an established method in the field of trucks and heavy diesel cars, but applying it to ships requires further research and development. The demands on ship engines are different, not only due to the large scales but also because the engineering process is strongly based on numerical simulations. To allow the validation of simulations at well-defined conditions and to investigate the fundamental processes, e.g. of the injection of urea solution for marine applications, a high pressure hot gas test rig was built up at the ITV. The current work focuses on the injection of urea solution by an air-blast atomizer. The spray breakup is the initial part of the urea decomposition, which is why reliable validation data is needed for modelling and simulating the respective spray and chemical processes. Therefore, the role of the atomization air flow rate in combination with different hot gas pressures was studied. The pressure influence is of particular interest, due to the possibility to install an SCR-system upstream the turbocharger of a marine engine. High speed shadowgraphy was applied to investigate the primary breakup of the urea spray. The breakup phenomena are discussed and combined with droplet spectra, which were measured by phase-Doppler anemometry (PDA). Apart from obtaining validation data, the study gives answers to the guiding question how to obtain acceptably fine sprays by using minimal atomization air under various circumstances.
CitationHöltermann, M., Wichmar, J., and Dinkelacker, F., "Influence of the Backpressure on Urea Sprays Generated by an Air-Blast Atomizer for Large-Scale SCR-Applications," SAE Technical Paper 2019-01-0046, 2019, https://doi.org/10.4271/2019-01-0046.
Data Sets - Support Documents
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|[Unnamed Dataset 2]|
- Nakajima, F. and Hamada, I. , “The State-of-the-Art Technology of NOx Control,” Catalysis Today 29:109-115, 1996, doi:10.1016/0920-5861(95)00288-X.
- Koebel, M., Elsener, M., and Kleemann, M. , “Urea-SCR: A Promising Technique to Reduce NOx Emissions from Automotive Diesel Engines,” Catalysis Today 59:335-345, 2000, doi:10.1016/S0920-5861(00)00299-6.
- International Maritime Organization (IMO) , “Prevention of Air Pollution from Ships,” www.imo.org, accessed July 2018.
- Team Tec , “Rules and Regulations,” https://www.teamtec.no/wp-content/uploads/2017/01/ECA_Map-e1485424586546.jpg, accessed July 2018.
- Birkhold, F., Meingast, U., Wassermann, P., and Deutschmann, O. , “Modeling and Simulation of the Injection of Urea-Water-Solution for Automotive SCR DeNOx-Systems,” Applied Catalysis B 70:119-127, 2007, doi:10.1016/j.apcatb.2005.12.035.
- Grout, S., Blaisot, J.-B., Pajot, K., and Osbat, G. , “Experimental Investigation on the Injection of an Urea-Water Solution in Hot Air Stream for the SCR Application: Evaporation and Spray/Wall Interaction,” Fuel 106:166-177, 2013, doi:10.1016/j.fuel.2012.09.022.
- Lauer, T. , “Preparation of Ammonia from Liquid AdBlue - Modeling Approaches and Future Challenges,” Chemie Ingenieur Technik 90(6):783-794, 2018, doi:10.1002/cite.201700107.
- Kim, J., Ryu, S., and Ha, J. , “Numerical Prediction on the Characteristics of Spray-Induced Mixing and Thermal Decomposition of Urea Solution in SCR System,” in ASME 2004 Internal Combustion Engine Division Fall Technical Conference, 2004, 165-170, doi:10.1115/ICEF2004-0889.
- Spiteri, A., Dimopoulos Eggenschwiler, P., and Liao, Y. , “Comparison of Pressure and Air-Assisted Atomizers for Urea-SCR Injection in Diesel Engine Exhaust,” Bargende, M., Reuss, H.C., and Wiedemann, J. (eds), 14. Internationales Stuttgarter Symposium. Proceedings, (Wiesbaden, Springer Vieweg, 2014).
- Kaario, O., Vuorinen, V., Zhu, L., Larmi, M. et al. , “Mixing and Evaporation Analysis of a High-Pressure SCR System Using a Hybrid LES-RANS Approach,” Energy 120:827-841, 2017.
- Kaario, O., Sarjovaara, T., Ranta, O., Hulkkonen, T. et al. , “Comparing Breakup Models in a Novel High Injection Pressure SCR System Using Polyhedral Meshing,” SAE Technical Paper 2014-01-2816, 2014, doi:10.4271/2014-01-2816.
- Sandelin, K. and Peitz, D. , “SCR under Pressure-Pre-Turbocharger NOx Abatement for Marine 2-Stroke Diesel Engines,” presented at in 28th CIMAC World Congress on Combustion Engines, Helsinki, Finland, June 6-10, 2016.
- Durst, F. and Zare, M. , “Laser Doppler Measurements in Two-Phase Flow,” in Proceedings of the LDA Symposium Copenhagen (1975), 1975, 403-429.
- Kapulla, R. and Najera, S.B. , “Operation Conditions of a Phase Doppler Anemometer: Droplet Size Measurements with Laser Beam Power, Photomultiplier Voltage, Signal Gain and Signal-to-Noise Ratio as Parameters,” Measurement Science and Technology 17(1):221-227, 2006, doi:10.1088/0957-0233/17/1/034.