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DEVELOPMENT OF MULTI-TASK CATALYSTS FOR REMOVAL OF NOx AND TOXIC ORGANIC COMPOUNDS DURING COAL COMBUSTION [electronic resource].

Published
Washington, D.C. : United States. Dept. of Energy, 2002.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
Physical Description
52 pages : digital, PDF file
Additional Creators
United States. Department of Energy and United States. Department of Energy. Office of Scientific and Technical Information
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Summary
The work performed during this project focused on the identification of materials capable of providing high activity and selectivity for the selective catalytic reduction of nitric oxide with ammonia. The material surface characteristics were correlated with the catalytic behavior of our catalysts to increase our understanding and to help improve the DeNOₓ efficiency. The catalysts employed in this study include mixed oxide composite powders (TiO₂-Cr₂O₃, TiO₂-ZrO₂, TiO₂-WO₃, TiO₂-SiO₂, and TiO₂-Al₂O₃) loaded with varying amounts of V₂O₅, along with 5 different commercial sources of TiO₂. V₂O₅ was added to the commercial sources of TiO₂ to achieve monolayer coverage. Since the valence state of vanadium in the precursor solution during the impregnation step significantly impacted catalytic performance, catalysts were synthesized from both V{sup +4} and V{sup +5} solutions explain this phenomenon. Specifically, the synthesis of catalysts from V{sup 5+} precursor solutions yields lower-performance catalysts compared to the case of V{sup 4+} under identical conditions. Aging the vanadium precursor solution, which is associated with the reduction of V{sup 5+} to V{sup 4+} (VO₂⁺ → VO{sup 2+}), prior to impregnation results in catalysts with excellent catalytic behavior under identical activation and operating conditions. This work also added vanadia to TiO₂-based supports with low crystallinity. These supports, which have traditionally performed poorly, are now able to function as effective SCR catalysts. Increasing the acidity of the support by incorporating oxides such as WO₃ and Al₂O₃ significantly improves the SCR activity and nitrogen selectivity. It was also found that the supports should be synthesized with the simultaneous precipitation of the corresponding precursors. The mixed oxide catalysts possess Broensted and Lewis acid sites of comparable strength over a wide range of temperatures. Catalysts prepared from aged vanadium precursor solutions also demonstrated a wider temperature window for optimum operation.
Report Numbers
E 1.99:fg26-97ft97274--04
fg26-97ft97274--04
Subject(s)
Other Subject(s)
Note
Published through SciTech Connect.
02/04/2002.
"fg26-97ft97274--04"
Panagiotis G. Smirniotis; Robert G. Jenkins.
National Energy Technology Lab., Pittsburgh, PA (US)
National Energy Technology Lab., Morgantown, WV (US)
Type of Report and Period Covered Note
Final; 09/30/1997 - 10/31/2001
Final For Grant; 09/30/1997 - 10/31/2001
Funding Information
FG26-97FT97274
View MARC record | catkey: 13833576