Advertisement

Emission Control Science and Technology

, Volume 3, Issue 4, pp 275–288 | Cite as

Nitric Oxide Reduction of Heavy-Duty Diesel Off-Gas by NH3-SCR in Front of the Turbocharger

  • T. Rammelt
  • B. Torkashvand
  • C. Hauck
  • J. Böhm
  • R. Gläser
  • O. DeutschmannEmail author
SPECIAL ISSUE: 2017 MODEGAT SEPTEMBER 3-5, BAD HERRENALB, GERMANY

Abstract

This paper investigates the impacts and effects of higher pressure on NH3-SCR of NOx corresponding to positioning the SCR catalyst in front of the exhaust gas turbine, which is an option in heavy-duty and off-road diesel engine applications (1, 2, 3, 4). The influence of applied pressure up to 500 kPa on the selective catalytic reduction (SCR) of nitrogen oxides by NH3 over commercial V2O5/WO3-TiO2-type catalysts (VWT) is studied experimentally and numerically. The model includes a detailed reaction mechanism for standard and fast SCR and a two-dimensional description of the flow field and diffusion in the honeycomb-structured catalyst. The pressure effect on catalytic conversion, residence time, and mass transfer are examined for varying temperature and two different channel sizes, i.e., 25 and 300 cpsi (channels per square inch) at constant mass flux from the engine. Pre-turbo positioning of the catalyst leads to a significant increase in NOx conversion due to higher pressure aside from the positive temperature effect. However, with increasing channel size, diffusional mass transport limits the reaction rate, and reduces the benefit of increased residence time due to the decrease in diffusion rates with increasing pressure. The achievable increase in conversion is transformed into a length reduction of the catalyst.

Keywords

SCR Pre-turbo Diesel engine Aftertreatment 

Notes

Acknowledgements

We gratefully acknowledge the versatile technical and financial support of the Research Association for Combustion Engines e.V. (Forschungsvereinigung Verbrennungskraftmaschinen e.V. FVV) and the participating industrial partners from the automotive sector. We thank the Steinbeis GmbH für Technologietransfer (STZ 240 Reaktive Strömungen) for a cost-free academic license of DETCHEM™.

Notation

AV;Area velocity (m h−1)

V C Catalyst volume (m3)

S C Specific catalyst surface (m2 m−3)

rChannel radius (m)

ρdensity (kg m−3)

uAxial velocity (m s−1)

zAxial coordination (m)

ppressure (Pa)

henthalpy (J kg−1)

vRadial velocity (m s−1)

λThermal conductivity (J m−1 s−1 K−1)

Ttemperature (K)

j i Diffusion flux (mol m−2 s−1)

Y i Mass fraction of species i (–)

k i Reaction rate coefficient

C i Concentration of species i (mol)

θ i Surface coverage with species i (–)

E i Activation energy (kJ mol−1)

RUniversal gas constant (J mol−1 K−1)

τResidence time (s)

V R Volume flow (m3 s−1)

D ij Binary diffusion coefficient (m2 s−1)

N A Avogadro constant

\( {k}_B^3 \)Boltzmann constant

M ij Reduced mass (kg)

\( {\sigma}_{ij}^2 \)Reduced diameter (m)

\( {\Omega}_{ij}^{\left(l,s\right)\ast } \)Reduced collision integral

\( {T}_{ij}^{\ast } \)Reduced temperature(K)

Indices

i,jSpecies number

References

  1. 1.
    R. Bank, B. Buchholz, H. Harndorf, R. Rabe, U. Etzien in "Analyse des Konversionsverhaltens von SCR-Katalysatoren unter den Betriebsbedingungen IMO Tier III konformer Großdieselmotoren", 2. Rostocker Großmotorentagung, 17.-18. September 2012, ISBN 978–3–8169-3153-9Google Scholar
  2. 2.
    Joergl, V., Keller, P., Weber, O., Mueller-Haas, K.: Influence of pre turbo catalyst design on diesel engine performance, emissions and fuel economy. SAE Int. J. Fuels Lubr. 1, 82 (2009)CrossRefGoogle Scholar
  3. 3.
    M. Subramaniam, C. Hayes, D. Tomazic, M. Downey, C. Brüstle, Pre-turbo aftertreatment position for large bore diesel engines—compact & cost-effective aftertreatment with a fuel consumption advantage, SAE Technical Paper 2011–01-0299 (2011)Google Scholar
  4. 4.
    Günter, T., Schäfer, K., Pesek, J., Bertótiné Abai, A., Casapu, M., Deutschmann, O., Grunwaldt, J.-D.: Cu-SSZ-13 as pre-turbine NOx-removal-catalyst: impact of pressure and catalyst poisons. Appl. Catal. B. 198, 548 (2016)CrossRefGoogle Scholar
  5. 5.
    Konstandopoulos, A.G., Kostoglou, M., Beatrice, C., Di Blasio, G., Imren, A., Denbratt, I.: Impact of combination of EGR, SCR, and DPF technologies for the low-emission rail diesel engines. Emiss. Control. Sci. Technol. 1, 213 (2015)CrossRefGoogle Scholar
  6. 6.
    Yuan, X., Liu, H., Gao, Y.: Diesel engine SCR control: current development and future challenges. Emiss. Control. Sci. Technol. 1, 121 (2015)CrossRefGoogle Scholar
  7. 7.
    Nova, I., Colombo, M., Tronconi, E.: Kinetic modeling of dynamic aspects of the standard NH3-SCR reaction over V2O5-WO3 /TiO2 and Fe-zeolite commercial catalysts for the aftertreatment of diesel engines exhausts. Oil Gas Sci. Technol. 66, 681 (2011)CrossRefGoogle Scholar
  8. 8.
    Johnson, T.: Diesel emissions in review. SAE Int. J. Engines. 4, 143 (2011)CrossRefGoogle Scholar
  9. 9.
    Schildhauer, T.J., Elsener, M., Moser, J., Begsteiger, I., Chatterjee, D., Rusch, K., Kröcher, O.: Measurement of vanadium emissions from SCR catalysts by ICP-OES: method development and first results. Emiss. Control. Sci. Technol. 1, 292 (2015)CrossRefGoogle Scholar
  10. 10.
    Brack, W., Heine, B., Birkhold, F., Kruse, M., Deutschmann, O.: Formation of urea-based deposits in an exhaust system: numerical predictions and experimental observations on a hot gas test bench. Emiss. Control. Sci. Technol. 2, 115 (2016)CrossRefGoogle Scholar
  11. 11.
    Kannepalli, S., Bürger, A., Tischer, S., Deutschmann, O.: Model-based optimization of ammonia dosing in NH3-SCR of NOx for transient driving cycle: model development and simulation. Emiss. Control Sci. Technol. (2017).  https://doi.org/10.1007/s40825-017-0072-4
  12. 12.
    Kröcher, O., Elsener, M., Bothien, M.R., Dölling, W.: Pre-turbo SCR - influence of pressure on NOx reduction. MTZ Worldwide. 75, 4 (2014)CrossRefGoogle Scholar
  13. 13.
    Bermúdez, V., Serrano, J., Piqueras, P., Garcia Afonso, O.: Analysis of heavy-duty turbocharged diesel engine response under cold transient operation with a pre-turbo aftertreatment exhaust manifold configuration. Int. J. Eng. Res. 14, 341 (2013)CrossRefGoogle Scholar
  14. 14.
    O. Deutschmann, S. Tischer, S. Kleditzsch, V.M. Janardhanan, C. Correa, D. Chatterjee, N. Mladenov, H.D. Minh, DETCHEM Software package, version 2.3, www.detchem.com, 2013
  15. 15.
    Deutschmann, O.: Modeling of the interactions between catalytic surfaces and gas-phase. Catal. Lett. 145, 272 (2015)CrossRefGoogle Scholar
  16. 16.
    Chan, D., Tischer, S., Heck, J., Diehm, C., Deutschmann, O.: Correlation between catalytic activity and catalytic surface area of a Pt/Al2O3 DOC: an experimental and microkinetic modeling study. Appl. Catal. B Environ. 156-157, 153 (2014)CrossRefGoogle Scholar
  17. 17.
    B. Torkashvand, A. Gremminger, S. Valchera, M. Casapu, J.-D. Grunwaldt, O. Deutschmann: “The impact of pre-turbine catalyst placement on methane oxidation in lean-burn gas engines: An experimental and numerical study”, SAE Technical Paper 2017–01-1019 (2017)Google Scholar
  18. 18.
    Raja, L.L., Kee, R.J., Deutschmann, O., Warnatz, J., Schmidt, L.D.: A critical evaluation of Navier–Stokes, boundary-layer, and plug-flow models of the flow and chemistry in a catalytic-combustion monolith. Catal. Today. 59, 47 (2000)CrossRefGoogle Scholar
  19. 19.
    Kee, R.J., Coltrin, M.E., Glarborg, P.: Chemically Reacting Flow: Theory and Practice. Wiley Interscience, Hoboken (2003)CrossRefGoogle Scholar
  20. 20.
    Tischer, S., Correa, C., Deutschmann, O.: Transient three-dimensional simulation of a catalytic combustion monolith using detailed models for heterogeneous and homogeneous reactions and transport phenomena. Catal. Today. 69, 57 (2001)CrossRefGoogle Scholar
  21. 21.
    Nova, I., Ciardeli, C., Tronconi, E., Chatterje, D., Weibel, M.: Unifying redox kinetics for standard and fast NH3-SCR over a V2O5-WO3/TiO catalyst. AICHE J. 55, 1514 (2009)CrossRefGoogle Scholar
  22. 22.
    Tronconi, E., Nova, I., Ciardelli, C., Chatterje, D., Weibel, M.: Redox features in the catalytic mechanism of the standard and fast-SCR of NOx over V-based catalyst investigated by dynamic methods. J. Catal. 245, 1 (2007)CrossRefGoogle Scholar
  23. 23.
    Kee, R.J., Dixon-Lewis, G., Warnatz, J., Coltrin, M.E., Miller, J.A.: Sandia Report SAND86–8246. Sandia National Laboratories, Albuquerque (1986)Google Scholar
  24. 24.
    Matsuda, S., Kamo, T., Kato, A., Nakajima, F., Kumura, T., Kuroda, H.: Ind. Eng. Chem. Prod. Res. Dev. 21, 48 (1982)CrossRefGoogle Scholar
  25. 25.
    W.S. Kijlstra, N.J. Komen, A. Andreini, E.K. Poels, A. Bliek, Promotion and deactivation of V2O5/TiO2 SCR catalysts by SO2 at low temperature, 11th International Congress On Catalysis - 40th Anniversary, Pts A and B 101, 951 (1996)Google Scholar
  26. 26.
    Baltin, G., Koser, H., Wendlandt, K.P.: Sulfuric acid formation over ammonium sulfate loaded V2O5–WO3/TiO2 catalysts by DeNOx reaction with NOx. Catal. Today. 75, 339 (2002)CrossRefGoogle Scholar
  27. 27.
    Ha Heon Phil, M.P.R., Kumar, P.A., Ju, L.K., Hyo, J.S.: Appl. Catal. B. 78, 301 (2008)Google Scholar
  28. 28.
    Tronconi, E., Cavanna, A., Orsenigo, C., Forzatti, P.: Transient kinetics of SO2 oxidation over SCR-DeNOx monolith catalysts. Ind. Eng. Chem. Res. 38, 2593 (1999)CrossRefGoogle Scholar
  29. 29.
    Svachula, J., Alemany, L.J., Ferlazzo, N., Forzatti, P., Tronconi, E., Bregani, F.: Oxidation of SO2 to SO3 over honeycomb denoxing catalysts. Ind. Eng. Chem. Res. 32, 826 (1993)CrossRefGoogle Scholar
  30. 30.
    Dunn, J.P., Koppula, P.R., Stenger, H.G., Wachs, I.E.: Oxidation of sulfur dioxide to sulfur trioxide over supported vanadia catalysts. Appl. Catal. B. 19, 10 (1998)CrossRefGoogle Scholar

Copyright information

© Springer International Publishing AG 2017

Authors and Affiliations

  1. 1.Institute of Chemical TechnologyUniversität LeipzigLeipzigGermany
  2. 2.Institute of Chemical Technology and Polymer ChemistryKarlsruhe Institute of TechnologyKarlsruheGermany

Personalised recommendations