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Chemical deactivation of V2O5/WO3–TiO2 SCR catalysts by additives and impurities from fuels, lubrication oils, and urea solution: I. Catalytic studies

Paper ID Volume ID Publish Year Pages File Format Full-Text
48388 46505 2008 13 PDF Available
Title
Chemical deactivation of V2O5/WO3–TiO2 SCR catalysts by additives and impurities from fuels, lubrication oils, and urea solution: I. Catalytic studies
Abstract

The influence of the combustion products of different lubrication oil additives (Ca, Mg, Zn, P, B, Mo) and impurities in Diesel fuel (K from raps methyl ester) or urea solution (Ca, K) on the activity and selectivity of vanadia-based SCR catalysts were investigated. Standard V2O5/WO3–TiO2 catalysts coated on metal substrates (400 cpsi) were impregnated with water soluble compounds of these elements and calcined at 400 and 550 °C, in order to investigate the chemical deactivation potential of different elements and combinations of them.It was found that potassium strongly reduced the adsorption equilibrium constant KNH3KNH3of ammonia. At small ammonia concentrations in the feed, only part of the active sites were covered with ammonia resulting in a reduced SCR reaction rate. At high ammonia concentrations, the surface coverage and SCR reaction rate increased, but high SCR activity at concurrent low ammonia emissions was impossible. Calcium caused less deactivation than potassium and did not affect the ammonia adsorption to the same extent, but it lowered the intrinsic SCR reaction rate. Moreover, deactivation by calcium was much reduced if counter-ions of inorganic acids were present (order of improvement: SO42− > PO43− > BO33−). Zinc was again less deactivating than calcium, but the positive effect of the counter-ions was weaker than in case of calcium. The degree of N2O production at T > 500 °C, which is typical for V2O5/WO3–TiO2 catalysts, was not influenced by the different compounds, except for molybdenum, which induced a small increase in N2O formation.

Keywords
Selective catalytic reduction; DeNOx; SCR catalyst; Vanadia; Deactivation; Ammonia adsorption
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Chemical deactivation of V2O5/WO3–TiO2 SCR catalysts by additives and impurities from fuels, lubrication oils, and urea solution: I. Catalytic studies
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 77, Issues 3–4, 10 January 2008, Pages 215–227
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