Local ammonia storage and ammonia inhibition in a monolithic copper-beta zeolite SCR catalyst

Journal Article · Sun Jan 01 00:00:00 EST 2012 · Applied Catalysis B

DOI:https://doi.org/10.1016/j.apcatb.2012.07.019· OSTI ID:1048149

Auvray, Xavier P ^[1]; Partridge, Jr, William P ^[2]; Choi, Jae-Soon ^[2]; Pihl, Josh A ^[2]; Yezerets, Alex ^[3]; Kamasamudram, Krishna ^[3]; Currier, Neal ^[3]; Olsson, Louise ^[1]

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1. Chalmers University of Technology, Sweden
2. ORNL
3. Cummins, Inc

Selective catalytic reduction of NO with NH{sub 3} was studied on a Cu-beta zeolite catalyst, with specific focus on the distributed NH{sub 3} capacity utilization and inhibition. In addition, several other relevant catalyst parameter distributions were quantified including the SCR zone, or catalyst region where SCR occurs, and NO and NH{sub 3} oxidation. We show that the full NH{sub 3} capacity (100% coverage) is used within the SCR zone for a range of temperatures. By corollary, unused NH{sub 3} capacity exists downstream of the SCR zone. Consequently, the unused capacity relative to the total capacity is indicative of the portion of the catalyst unused for SCR. Dynamic NH{sub 3} inhibition distributions, which create local transient conversion inflections, are measured. Dynamic inhibition is observed where the gas phase NH{sub 3} and NO concentrations are high, driving rapid NH{sub 3} coverage buildup and SCR. Accordingly, we observe dynamic inhibition at low temperatures and in hydrothermally aged states, but predict its existence very near the catalyst front in higher conversion conditions where we did not specifically monitor its impact. While this paper addresses some general distributed SCR performance parameters including Oxidation and SCR zone, our major new contributions are associated with the NH{sub 3} capacity saturation within the SCR zone and dynamic inhibition distributions and the associated observations. These new insights are relevant to developing accurate models, designs and control strategies for automotive SCR catalyst applications.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fuels, Engines and Emissions Research Center (FEERC)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1048149
• Journal Information: Applied Catalysis B, Vol. 126; ISSN 0926-3373
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AMMONIA
BUILDUP
CAPACITY
CATALYSTS
MONITORS
OXIDATION
PERFORMANCE
SATURATION
SELECTIVE CATALYTIC REDUCTION
STORAGE
TRANSIENTS
ZEOLITES
SCR
Ammonia
NO
NH3 Capacity
NH3 Inhibition
Distributed Reactions
Spatially Resolved Capillary Inlet Mass Spectrometry
SpaciMS
Cu-Beta
zeolite