Microkinetic Modeling of Lean NO<sub>x</sub> Trap Storage and Regeneration [electronic resource].
- Published
- Washington, D.C. : United States. National Nuclear Security Administration, 2011.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy - Physical Description
- 84 pages : digital, PDF file
- Additional Creators
- Sandia National Laboratories, United States. National Nuclear Security Administration, and United States. Department of Energy. Office of Scientific and Technical Information
Access Online
- Restrictions on Access
- Free-to-read Unrestricted online access
- Summary
- A microkinetic chemical reaction mechanism capable of describing both the storage and regeneration processes in a fully formulated lean NOx trap (LNT) is presented. The mechanism includes steps occurring on the precious metal, barium oxide (NOx storage), and cerium oxide (oxygen storage) sites of the catalyst. The complete reaction set is used in conjunction with a transient plug flow reactor code (including boundary layer mass transfer) to simulate not only a set of long storage/regeneration cycles with a CO/H2 reductant, but also a series of steady flow temperature sweep experiments that were previously analyzed with just a precious metal mechanism and a steady state code neglecting mass transfer. The results show that, while mass transfer effects are generally minor, NOx storage is not negligible during some of the temperature ramps, necessitating a re-evaluation of the precious metal kinetic parameters. The parameters for the entire mechanism are inferred by finding the best overall fit to the complete set of experiments. Rigorous thermodynamic consistency is enforced for parallel reaction pathways and with respect to known data for all of the gas phase species involved. It is found that, with a few minor exceptions, all of the basic experimental observations can be reproduced with the transient simulations. In addition to accounting for normal cycling behavior, the final mechanism should provide a starting point for the description of further LNT phenomena such as desulfation and the role of alternative reductants.
- Report Numbers
- E 1.99:sand2011--9090
sand2011--9090 - Subject(s)
- Note
- Published through SciTech Connect.
12/01/2011.
"sand2011--9090"
"456672"
Richard S. Larson; V. Kalyana Chakravarthy; Josh A. Pihl; C. Stuart Daw. - Funding Information
- AC04-94AL85000
View MARC record | catkey: 24046948