ANALYSIS OF NOx CONVERSION USING A QUASI 2-D NH 3 -SCR MODEL WITH DETAILED REACTIONS

Event
SAE International Powertrains, Fuels and Lubricants Meeting
Authors Abstract
Content
We have constructed a quasi-2-dimensional NH₃-SCR model with detailed surface reactions to analyze the NOx conversion mechanism and reasons for its inhibition at low temperatures. The model consists of seven detailed surface reactions proposed by Grozzale et al., and calculates longitudinal gas flow, gas phase-catalyst phase mass transfer, and mass diffusion within the catalyst phase in the depth dimension. Using the model, we have analyzed the results of pulsed ammonia (NH₃) feed tests at various catalyst temperatures, and results show that ammonium nitrate (NH₄NO₃) is the inhibitor in NH₃-SCR reactions at low temperatures. In addition, we found that cutting the supply of NH₃ causes decomposition of NH₄NO₃, providing surface ammonia (NH₄+), which rapidly reacts with adjacent NOx, leading to an instantaneous rise in nitrogen (N₂) formation. However, the decomposition rate of NH₄NO₃ depends on the catalyst temperature; hence, an optimum addition of reductants, depending on the NH₄NO₃ formation/decomposition rate (and thus catalyst temperature) is required to maximize the NOx conversion efficiency of SCR catalysts.
Meta TagsDetails
DOI
https://doi.org/10.4271/2011-01-2081
Pages
7
Citation
Kusaka, J., Shimao, H., Yano, H., Murasaki, T. et al., "ANALYSIS OF NOx CONVERSION USING A QUASI 2-D NH 3 -SCR MODEL WITH DETAILED REACTIONS," SAE Int. J. Fuels Lubr. 5(1):352-358, 2012, https://doi.org/10.4271/2011-01-2081.
Additional Details
Publisher
Published
Aug 30, 2011
Product Code
2011-01-2081
Content Type
Journal Article
Language
English