Reversible and irreversible deactivation of Cu-CHA NH3-SCRcatalysts by SO2 and SO3
| Autor: | Yasser Jangjou, Peter S. Hammershøi, William S. Epling, Ton V. W. Janssens, Anker Degn Jensen |
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| Rok vydání: | 2018 |
| Předmět: |
Sulfur oxides
Process Chemistry and Technology Dry gas Deactivation chemistry.chemical_element Selective catalytic reduction 02 engineering and technology Activation energy 010402 general chemistry 021001 nanoscience & nanotechnology Photochemistry 01 natural sciences Sulfur Catalysis 0104 chemical sciences chemistry.chemical_compound chemistry Cu-CHA Regeneration NH3-SCR 0210 nano-technology Zeolite NOx General Environmental Science |
| Zdroj: | Hammershøi, P S, Jangjou, Y, Epling, W S, Jensen, A D & Janssens, T V W 2018, ' Reversible and irreversible deactivation of Cu-CHA NH 3-SCR catalysts by SO 2 and SO 3 ', Applied Catalysis B: Environmental, vol. 226, pp. 38–45 . https://doi.org/10.1016/j.apcatb.2017.12.018 |
| ISSN: | 0926-3373 |
| DOI: | 10.1016/j.apcatb.2017.12.018 |
| Popis: | Sulfur oxides are a common source for the deactivation of Cu-exchanged CHA zeolite based catalysts used for NOx reduction in diesel exhausts by selective catalytic reduction with NH3 (NH3-SCR). Since water and possible formation of SO3 affect the deactivation of Cu-CHA catalysts, the deactivation in the presence of SO2 or a mixture of SO2 and SO3 was studied by measuring the SCR activity in wet and dry gas at 200 and 550 °C. The estimated S-content in the catalysts before and after 4 h regeneration at 550 °C in NO, NH3, O2 and H2O was related to the deactivation. The deactivation can be divided into two parts: a reversible deactivation that is restored by the regeneration treatment, and an irreversible part. The irreversible deactivation does not affect the activation energy for NH3-SCR and display a 1:1 correlation with the S-content, consistent with deactivation by Cu-sulfate formation. The reversible deactivation results in a lower activation energy and a deactivation that is larger than expected from the S-content. The presence of SO3 at 200 °C leads to higher reversible and irreversible deactivation, but has no significant impact at 550 °C. Furthermore, the irreversible deactivation is always higher when exposed at 200 °C than at 550 °C, and in wet conditions, compared to a dry feed. The deactivation is predominantly reversible, making regeneration at 550 °C a realistic approach to handle S-poisoning in exhaust systems. |
| Databáze: | OpenAIRE |
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