Synthesis and characterization of copper-zirconia based catalysts for DeNOx in biomass fired units
Advancing the chemical engineering fundamentals
Catalysis - II (T2-13b)
Keywords: SCR, Biomass, Copper, ZrO2, deactivation
Synthesis and characterization of copper-zirconia based catalysts for DeNOx in biomass fired units
S. B. Rasmussen*1,2,4 J. Due-Hansen1, A. Kustov1, A.D. Jensen2; P. Simonsen3;
R. Fehrmann1, M.Yates4, J. Blanco4
1) CSG & Dep. of Chemistry, DTU, DK-2800 Kgs. Lyngby, Denmark;
2) CHEC, Dep. of Chemical Engineering, DTU, DK-2800 Kgs. Lyngby, Denmark
3) Dong ENERGY, Teglholmen, A.C. Meyers Vænge 9, DK-2450 København
4) Instituto de Catálisis y Petroleoquímica, CSIC, c/ Marie Curie 2, Cantoblanco, 28049 Madrid, Spain
Vanadium based (V2O5/TiO2) SCR catalysts are commonly used for removal of NOX from fossil fuel fired power plant flue gases. When biomass is fired alone or in combination with conventional fossil fuels, the traditional catalyst suffers from rapid deactivation due to poisoning, where Lewis bases such as potassium oxides and or chlorides from the combusted biomass eliminate the catalytically active V-OH (Brønsted) acid centres on the catalyst surface. This has lead to an investigation of alternative materials, such as acidified zirconia based carriers with other active transition metal oxide centres. One possible way to increase catalyst resistance to alkaline poisons is the use of supports, having high or super-acidic properties which would interact more strongly with potassium than vanadium species. Among suitable oxide supports, zirconia and titania are the most attractive because they show high acidity along with high thermal and hydrothermal stability. In this work we report results on a CuO-ZrO2-SO4 system - a candidate catalyst material for use as a potassium resistant catalyst in biomass fired power plants. Our results indicate that dimeric or oligomeric Cu-species were responsible for the catalytic activity. The catalytic system has an optimal loading of around 3wt.% CuO, since higher metal oxide content leads to loss of selectivity. Activity measurements and EPR spectroscopy have demonstrated that potassium attack occurs on the active sites. However, this is expected to be at a slower rate than the corresponding deactivation mechanism of the traditional V2O5/TiO2 SCR catalyst.
Presented Thursday 20, 11:00 to 11:20, in session Catalysis - II (T2-13b).
