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The effects of regeneration conditions on NOX and NH3 release from NOX storage/reduction catalysts

Paper ID Volume ID Publish Year Pages File Format Full-Text
48763 46521 2007 13 PDF Available
Title
The effects of regeneration conditions on NOX and NH3 release from NOX storage/reduction catalysts
Abstract

A standard protocol developed by the Cross-Cut Lean Exhaust Emissions Reduction Simulations (CLEERS) group was used to investigate the evolution of N-byproduct species and the release of unreduced NOX from a commercial NOX storage/reduction (NSR) catalyst. NH3 was readily formed at temperatures below 375 °C, and the onset of its formation was typically observed coincident with reductant breakthrough. N2O was also observed at these lower test temperatures. The rate of NOX release, as both NO and NO2, increased with increasing temperature due to decreasing nitrate stability. Reduction of NOX necessarily involved the presence of reductant, which was also used to titrate oxygen species from oxygen-storage components such as ceria. Changes in the release of unreduced NOX from the catalyst as a function of temperature were directly attributable to the temperature dependencies of nitrate stability and decomposition, NOX diffusion to the precious metal sites, the rate of the NOX reduction reaction and the rate of reduction of these oxygen-storage components. Furthermore, by accounting for the amount of reductant needed for titration of the oxygen-storage components and the amount of NOX trapped, mass balance calculations were performed and used to estimate the amounts of residual nitrates on the catalyst surface after regeneration. These calculations indicate that only at the lower temperatures were the regenerations not effective enough to remove all the trapped NOX.

Keywords
NOX reduction; NOX storage; Diesel emissions
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The effects of regeneration conditions on NOX and NH3 release from NOX storage/reduction catalysts
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 74, Issues 1–2, 18 June 2007, Pages 117–129
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us