Emission Control Science and Technology

, Volume 4, Issue 3, pp 172–197 | Cite as

Development and Validation of a Two-Site Kinetic Model for NH3-SCR over Cu-SSZ-13. Part 2. Full-Scale Model Validation, ASC Model Development, and SCR-ASC Model Application

  • Rohil DayaEmail author
  • Chintan Desai
  • Bruce Vernham
Special Issue: 2017 CLEERS October 3 - 5, Ann Arbor, MI, USA


We present herein the final part in the development and validation of a two-site kinetic model for NH3-SCR over Cu-SSZ-13. To predict tailpipe emissions accurately, it was necessary to combine the kinetic model of the SCR catalyst developed in part I (Daya et al. 2018), with a reaction-diffusion model of the dual-layer ammonia slip catalyst (ASC). This dual-layer ASC model was developed following a three-step process, including development of the kinetic models of the individual layers, followed by parameterization of a parallel pore diffusion model of the dual-layer ASC. Reactor-scale validation of the dual-layer ASC model confirmed the kinetic model accuracy and highlighted the significance of intra-porous diffusion. Following this, the SCR model developed in part I of this paper was validated on an engine dynamometer through comprehensive steady-state experiments with inlet NH3 to NOx ratio (ANR) sweeps. The final SCR and ASC models were then evaluated on cold and hot heavy-duty transient (HDT) cycles, to examine the capability of predicting tailpipe NOx, NH3 slip as well as storage-based dynamics. Overall cycle-averaged NOx conversion was predicted within 3% using these models. Validated models have significant application in model-based control as well as improving catalyst design through improved functional understanding. The present Cu-SSZ-13 SCR model was simulated using the four-step SCR protocol (Kamasamudram et al. Catal. Today 151(3):212–222) to calculate the intra-catalyst dynamic capacity. These numerical experiments showed that the dynamic capacity decreases upon hydrothermal aging but leads to higher NOx conversion under standard and fast SCR conditions at 250 °C. This increase in NOx conversion is due to more uniform NH3 storage along the length of the catalyst, leading to higher NH3 utilization near the rear of the aged catalyst. Similar numerical experiments on the dual-layer ASC model demonstrated intra-layer washcoat distributions causing NO slip during transient drive cycles for both hydrothermal aging conditions.


Global Kinetic Model Dual-Layer ASC Model Intra-Porous Diffusion Drive Cycle Validation Hydrothermal Ageing 



effective diffusivity m2/s


species bulk diffusivity m2/s


Knudsen diffusivity m2/s


washcoat pore diameter m


washcoat tortuosity


washcoat porosity



The authors would like to acknowledge Cormetech Inc. for executing the test protocol, supplying the reactor data, and assisting with the reactor setup description. Furthermore, the Gamma Technologies Aftertreatment support team helped us with useful discussions and continuous assistance with modeling work.

Supplementary material

40825_2018_94_MOESM1_ESM.docx (2.5 mb)
ESM1 (DOCX 2596 kb)


  1. 1.
    Mondt, J.R.: Cleaner Cars: the History and Technology of Emission Control since the 1960s. (2000)Google Scholar
  2. 2.
    Johnson, T., Joshi, A.: Review of vehicle engine efficiency and emissions (No. 2017–01-0907). SAE Technical Paper. (2017)Google Scholar
  3. 3.
    Sharp, C., Webb, C.C., Yoon, S., Carter, M., Henry, C.: Achieving ultra low NOX emissions levels with a 2017 heavy-duty on-highway TC diesel engine-comparison of advanced technology approaches. SAE Int. J. Engines. 10(2017-01-0956) (2017)Google Scholar
  4. 4.
    Koebel, M., Madia, G., Elsener, M.: Selective catalytic reduction of NO and NO2 at low temperatures. Catal. Today. 73(3), 239–247 (2002)CrossRefGoogle Scholar
  5. 5.
    Yim, S.D., Kim, S.J., Baik, J.H., Nam, I.S., Mok, Y.S., Lee, J.H., et al.: Decomposition of urea into NH3 for the SCR process. Ind. Eng. Chem. Res. 43(16), 4856–4863 (2004)CrossRefGoogle Scholar
  6. 6.
    Nova, I., Tronconi, E. (eds.): Urea-SCR Technology for deNOx after Treatment of Diesel Exhausts. Springer, New York (2014)Google Scholar
  7. 7.
    Kamasamudram, K., Yezerets, A., Currier, N., Castagnola, M., Chen, H.Y.: New insights into reaction mechanism of selective catalytic ammonia oxidation technology for diesel aftertreatment applications. SAE Int. J. Engines. 4(2011–01-1314), 1810–1821 (2011)CrossRefGoogle Scholar
  8. 8.
    Chi, J.N.: Control challenges for optimal NOx conversion efficiency from SCR aftertreatment systems (No. 2009–01-0905). SAE Technical Paper. (2009)Google Scholar
  9. 9.
    Jabłońska, M., Palkovits, R.: Copper based catalysts for the selective ammonia oxidation into nitrogen and water vapour—recent trends and open challenges. Appl. Catal. B Environ. 181, 332–351 (2016)CrossRefGoogle Scholar
  10. 10.
    Park, S.J., Jin, S.Y.: Effect of ozone treatment on ammonia removal of activated carbons. J. Colloid Interface Sci. 286(1), 417–419 (2005)CrossRefGoogle Scholar
  11. 11.
    Girard, J.W., Cavataio, G., Lambert, C.K.: The influence of ammonia slip catalysts on ammonia, N2O and NOx emissions for diesel engines (No. 2007–01-1572). SAE Technical Paper. (2007)Google Scholar
  12. 12.
    Colombo, M., Nova, I., Tronconi, E.: A simplified approach to modeling of dual-layer ammonia slip catalysts. Chem. Eng. Sci. 75, 75–83 (2012)CrossRefGoogle Scholar
  13. 13.
    Scheuer, A., Votsmeier, M., Schuler, A., Gieshoff, J., Drochner, A., Vogel, H.: NH3-slip catalysts: experiments versus mechanistic modelling. Top. Catal. 52(13–20), 1847–1851 (2009)CrossRefGoogle Scholar
  14. 14.
    Scheuer, A., Hauptmann, W., Drochner, A., Gieshoff, J., Vogel, H., Votsmeier, M.: Dual layer automotive ammonia oxidation catalysts: experiments and computer simulation. Appl. Catal. B Environ. 111, 445–455 (2012)CrossRefGoogle Scholar
  15. 15.
    Sukumar, B., Dai, J., Johansson, A., Markatou, P., Ahmadinejad, M., Watling, T., ..., Szailer, T.: Modeling of dual layer ammonia slip catalysts (ASC) (No. 2012–01-1294). SAE Technical Paper. (2012)Google Scholar
  16. 16.
    Colombo, M., Nova, I., Tronconi, E., Schmeißer, V., Bandl-Konrad, B., Zimmermann, L.: NO/NO 2/N 2 O–NH 3 SCR reactions over a commercial Fe-zeolite catalyst for diesel exhaust aftertreatment: intrinsic kinetics and monolith converter modelling. Appl. Catal. B Environ. 111, 106–118 (2012)CrossRefGoogle Scholar
  17. 17.
    Shrestha, S., Harold, M.P., Kamasamudram, K.: Experimental and modeling study of selective ammonia oxidation on multi-functional washcoated monolith catalysts. Chem. Eng. J. 278, 24–35 (2015)CrossRefGoogle Scholar
  18. 18.
    Shrestha, S., Harold, M.P., Kamasamudram, K., Kumar, A., Olsson, L., Leistner, K.: Selective oxidation of ammonia to nitrogen on bi-functional Cu–SSZ-13 and Pt/Al 2 O 3 monolith catalyst. Catal. Today. 267, 130–144 (2016)CrossRefGoogle Scholar
  19. 19.
    Gao, F., Kwak, J.H., Szanyi, J., Peden, C.H.: Current understanding of cu-exchanged Chabazite molecular sieves for use as commercial diesel engine DeNOx catalysts. Top. Catal. 56(15–17), 1441–1459 (2013)CrossRefGoogle Scholar
  20. 20.
    Colombo, M., Nova, I., Tronconi, E., Schmeißer, V., Bandl-Konrad, B., Zimmermann, L.: Experimental and modeling study of a dual-layer (SCR+ PGM) NH 3 slip monolith catalyst (ASC) for automotive SCR aftertreatment systems. Part 1. Kinetics for the PGM component and analysis of SCR/PGM interactions. Appl. Catal. B Environ. 142, 861–876 (2013)CrossRefGoogle Scholar
  21. 21.
    Colombo, M., Nova, I., Tronconi, E., Schmeißer, V., Bandl-Konrad, B., Zimmermann, L.R.: Experimental and modeling study of a dual-layer (SCR+ PGM) NH 3 slip monolith catalyst (ASC) for automotive SCR after treatment systems. Part 2. Validation of PGM kinetics and modeling of the dual-layer ASC monolith. Appl. Catal. B Environ. 142, 337–343 (2013)CrossRefGoogle Scholar
  22. 22.
    Scheuer, A., Drochner, A., Gieshoff, J., Vogel, H., Votsmeier, M.: Runtime efficient simulation of monolith catalysts with a dual-layer washcoat. Catal. Today. 188(1), 70–79 (2012)CrossRefGoogle Scholar
  23. 23.
    Daya, R., Desai, C., Vernham, B.: Development and validation of a two-site kinetic model for NH3-SCR over Cu-SSZ-13. Part 1. Detailed global kinetics development based on mechanistic considerations. Emission Control Science and Technology. (2018).
  24. 24.
    Bissett, E.J.: An asymptotic solution for washcoat pore diffusion in catalytic monoliths. Emission Control Sci Technol. 1(1), 3–16 (2015)CrossRefGoogle Scholar
  25. 25.
    GT-Suite Exhaust Aftertreatment Application Manual v2017Google Scholar
  26. 26.
    Fuller, E.N., Schettler, P.D., Giddings, J.C.: New method for prediction of binary gas-phase diffusion coefficients. Ind. Eng. Chem. 58(5), 18–27 (1966)CrossRefGoogle Scholar
  27. 27.
    Hindmarsh, A.C.: LSODE and LSODI, two new initial value ordinary differential equation solvers. ACM Signum Newslett. 15(4), 10–11 (1980)CrossRefGoogle Scholar
  28. 28.
    Centeno, M.A., Carrizosa, I., Odriozola, J.A.: In situ DRIFTS study of the SCR reaction of NO with NH 3 in the presence of O 2 over lanthanide doped V 2 O 5/Al 2 O 3 catalysts. Applied Catalysis B : Environ. 19(1), 67–73 (1998)Google Scholar
  29. 29.
    Chatterjee, D., Burkhardt, T., Weibel, M., Nova, I., Grossale, A., Tronconi, E.: Numerical simulation of zeolite-and V-based SCR catalytic converters (No. 2007–01-1136). SAE Technical Paper. (2007)Google Scholar
  30. 30.
    Deb, K., & Jain, H.: An evolutionary many-objective optimization algorithm using reference-point-based nondominated sorting approach, part I: Solving problems with box constraints. IEEE Trans. Evol. Comput. 18(4), 577–601 (2014)Google Scholar
  31. 31.
    Nelder, J.A., & Mead, R.: A simplex method for function minimization. Comput. J. 7(4), 308–313 (2014)Google Scholar
  32. 32.
    Kamasamudram, K., Currier, N.W., Chen, X., Yezerets, A.: Overview of the practically important behaviors of zeolite-based urea-SCR catalysts, using compact experimental protocol. Catal. Today. 151(3), 212–222 (2010)CrossRefGoogle Scholar
  33. 33.
    Partridge Jr, W.P., Choi, J.S., Parks, I.I., James, E., Currier, N., Yezerets, A., ..., Kamasamudram, K.: Cummins/ORNL-FEERC CRADA: NOx control & measurement technology for heavy-duty diesel engines (No. ORNL/TM-2017/76). Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Fuels, Engines and Emissions Research Center. (2017)Google Scholar
  34. 34.
    Joshi, S.Y., Kumar, A., Luo, J., Kamasamudram, K., Currier, N.W., & Yezerets, A.: New insights into the mechanism of NH 3-SCR over Cu-and Fe-zeolite catalyst: apparent negative activation energy at high temperature and catalyst unit design consequences. Appl. Catal. B Environ. (2018)Google Scholar

Copyright information

© Springer Nature Switzerland AG 2018

Authors and Affiliations

  1. 1.Isuzu Technical Center of AmericaPlymouthUSA

Personalised recommendations