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Title: Modeling Species Inhibition and Competitive Adsorption in Urea-SCR Catalysts

Abstract

Although the urea-SCR technology exhibits high NOx reduction efficiency over a wide range of temperatures among the lean NOx reduction technologies, further improvement in low-temperature performance is required to meet the future emission standards and to lower the system cost. In order to improve the catalyst technologies and optimize the system performance, it is critical to understand the reaction mechanisms and catalyst behaviors with respect to operating conditions. Urea-SCR catalysts exhibit poor NOx reduction performance at low temperature operating conditions (T < 150 C). We postulate that the poor performance is either due to NH3 storage inhibition by species like hydrocarbons or due to competitive adsorption between NH3 and other adsorbates such as H2O and hydrocarbons in the exhaust stream. In this paper we attempt to develop one-dimensional models to characterize inhibition and competitive adsorption in Fe-zeolite based urea-SCR catalysts based on bench reactor experiments. We further use the competitive adsorption (CA) model to develop a standard SCR model based on previously identified kinetics. Simulation results indicate that the CA model predicts catalyst outlet NO and NH3 concentrations with minimal root mean square error.

Authors:
; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1039127
Report Number(s):
PNNL-SA-84953
VT0401000; TRN: US201209%%190
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Conference
Resource Relation:
Conference: SAE World Congress and Exhibition, April 24-26, 2012, Detroit, Michigan, SAE Technical Paper 2012-01-1295
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ADSORPTION; CATALYSTS; EFFICIENCY; HYDROCARBONS; KINETICS; PERFORMANCE; REACTION KINETICS; SIMULATION; STORAGE; Hydrocarbon Inhibition, Urea SCR Catalyst, NOx Control, Competitive Adsorption, Modeling, Heavy Duty Diesel

Citation Formats

Devarakonda, Maruthi N, Tonkyn, Russell G, and Lee, Jong H. Modeling Species Inhibition and Competitive Adsorption in Urea-SCR Catalysts. United States: N. p., 2012. Web. doi:10.4271/2012-01-1295.
Devarakonda, Maruthi N, Tonkyn, Russell G, & Lee, Jong H. Modeling Species Inhibition and Competitive Adsorption in Urea-SCR Catalysts. United States. doi:10.4271/2012-01-1295.
Devarakonda, Maruthi N, Tonkyn, Russell G, and Lee, Jong H. Mon . "Modeling Species Inhibition and Competitive Adsorption in Urea-SCR Catalysts". United States. doi:10.4271/2012-01-1295.
@article{osti_1039127,
title = {Modeling Species Inhibition and Competitive Adsorption in Urea-SCR Catalysts},
author = {Devarakonda, Maruthi N and Tonkyn, Russell G and Lee, Jong H},
abstractNote = {Although the urea-SCR technology exhibits high NOx reduction efficiency over a wide range of temperatures among the lean NOx reduction technologies, further improvement in low-temperature performance is required to meet the future emission standards and to lower the system cost. In order to improve the catalyst technologies and optimize the system performance, it is critical to understand the reaction mechanisms and catalyst behaviors with respect to operating conditions. Urea-SCR catalysts exhibit poor NOx reduction performance at low temperature operating conditions (T < 150 C). We postulate that the poor performance is either due to NH3 storage inhibition by species like hydrocarbons or due to competitive adsorption between NH3 and other adsorbates such as H2O and hydrocarbons in the exhaust stream. In this paper we attempt to develop one-dimensional models to characterize inhibition and competitive adsorption in Fe-zeolite based urea-SCR catalysts based on bench reactor experiments. We further use the competitive adsorption (CA) model to develop a standard SCR model based on previously identified kinetics. Simulation results indicate that the CA model predicts catalyst outlet NO and NH3 concentrations with minimal root mean square error.},
doi = {10.4271/2012-01-1295},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2012},
month = {4}
}

Conference:
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