Spatially resolved in situ measurements of transient species breakthrough during cyclic, low-temperature regeneration of a monolithic Pt/K/Al2O3 NOx storage-reduction catalyst

Choi, Jae‐Soon; Partridge, William P.; Daw, C. Stuart

doi:10.1016/j.apcata.2005.06.025

Cited by 87 publications

(36 citation statements)

References 25 publications

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“…Previous research has shown that gradients in surface chemistry and temperature on NSR catalysts form during operation [14,15]. As part of the cycle involves sorption, there is an expected NO X -species surface concentration gradient along the length of the catalyst bed, or monolith channel, and indeed such gradients have been inferred from gas species measurements inside a monolith channel during the trapping phase [14,15].…”

Section: Introductionmentioning

confidence: 99%

“…As part of the cycle involves sorption, there is an expected NO X -species surface concentration gradient along the length of the catalyst bed, or monolith channel, and indeed such gradients have been inferred from gas species measurements inside a monolith channel during the trapping phase [14,15]. Temperature gradients also form from reactions at the lean-to-rich or rich-to-lean phase transitions, between residual O 2 or reductant on the surface reacting with incoming reductant and O 2 .…”

Section: Introductionmentioning

confidence: 99%

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Spatially-Resolved Calorimetry: Using IR Thermography to Measure Temperature and Trapped NOX Distributions on a NOX Adsorber Catalyst

et al. 2008

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Spatial-and time-resolved temperature distributions over a Pt/Ba/Al 2 O 3 model NO X storage/reduction (NSR) catalyst were measured using infra-red thermography. The heat generated during regeneration was correlated to surface nitrate reduction, thereby revealing the concentration of surface nitrates at specific locations along the catalyst. The results demonstrate that there is more nitrate formation at upstream positions relative to downstream, or from front to back of the catalyst, with short trapping times. However, as more NO X was trapped on the catalyst during longer trapping times, it was found that the largest amount of NO X was trapped slightly downstream of the inlet, evolving to a local maximum in amount trapped. Applying infrared (IR) thermography to this system resulted in a spatially resolved calorimetry method via the correlation of temperature to the distribution of sorbed nitrate species along the catalyst.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Spatially-Resolved Calorimetry: Using IR Thermography to Measure Temperature and Trapped NOX Distributions on a NOX Adsorber Catalyst

et al. 2008

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“…There has also been work using IR thermography to observe spatial variations in temperature over catalysts [2] and is a less intrusive method. In terms of gas-phase concentration measurements, Oak Ridge National Laboratory has been developing spatially resolved capillary-inlet mass spectrometry (SpaciMS), which is a method to measure transient gas-phase concentration profiles [3,4].…”

Section: Introductionmentioning

confidence: 99%

Spatially-Resolved Temperature and Gas Species Changes in a Lean-Burn Engine Emissions Control Catalyst

Russell

Epling

Hess

et al. 2010

Ind. Eng. Chem. Res.

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SummaryInfra-red thermography and spatially-resolved capillary inlet mass spectrometry (SpaciMS) have been used to characterize hydrocarbon oxidation reactions occurring along a Pt/Al 2 O 3 monolith-supported catalyst, before and after thermal degradation. The combined techniques clearly show reaction location, and therefore catalyst use, and how these change with thermal aging. Two modes of thermal degradation were applied, one where the entire catalyst was exposed to one temperature and one where the upstream portion of the catalyst was exposed to high temperature. Results from both will be presented and compared.

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“…The necessity for ultra-fast responding gas analysis has been also addressed by other researchers. As an example, Choi et al [16,17] employ fast mass spectroscopy to study the regeneration events at various monolith positions. The regeneration presented in figure 6 was performed after saturation at 300°C.…”

Section: Regenerationmentioning

confidence: 99%

Modeling of the NO x trap and experimental validation using ultra-fast NO x analyzers

2007

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The present paper employs and validates a NO x trap model which attempts an optimum compromise between complexity and predictive accuracy. It is shown that using the same set of kinetic data, the model is able to predict the storage rates and the maximum storage amounts as function of temperature. Moreover, the model predicts with reasonable accuracy the NO breakthrough during rich-mode regeneration and the spontaneous/thermal NO 2 release when the temperature is increased in a saturated catalyst. The experimental findings highlight the importance of transient O 2 adsorption/desorption phenomena which are incorporated in the model. The use of ultra-fast responding NO/NO x analyzers was necessary for the study and modeling of the transient operation following inlet composition switches.

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Spatially resolved in situ measurements of transient species breakthrough during cyclic, low-temperature regeneration of a monolithic Pt/K/Al2O3 NOx storage-reduction catalyst

Cited by 87 publications

References 25 publications

Spatially-Resolved Calorimetry: Using IR Thermography to Measure Temperature and Trapped NOX Distributions on a NOX Adsorber Catalyst

Spatially-Resolved Calorimetry: Using IR Thermography to Measure Temperature and Trapped NOX Distributions on a NOX Adsorber Catalyst

Spatially-Resolved Temperature and Gas Species Changes in a Lean-Burn Engine Emissions Control Catalyst

Modeling of the NO x trap and experimental validation using ultra-fast NO x analyzers

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