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New Insight into SO 2 Poisoning and Regeneration of CeO 2 -WO 3 /TiO 2 and V 2 O 5 -WO 3 /TiO 2 Catalysts for Low-Temperature NH 3 -SCR.
- Source :
-
Environmental science & technology [Environ Sci Technol] 2018 Jun 19; Vol. 52 (12), pp. 7064-7071. Date of Electronic Publication: 2018 May 25. - Publication Year :
- 2018
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Abstract
- In this study, the poisoning effects of SO <subscript>2</subscript> on the V <subscript>2</subscript> O <subscript>5</subscript> -WO <subscript>3</subscript> /TiO <subscript>2</subscript> (1%VWTi) and CeO <subscript>2</subscript> -WO <subscript>3</subscript> /TiO <subscript>2</subscript> (5%CeWTi) selective catalytic reduction (SCR) catalysts were investigated in the presence of steam, and also the regeneration of deactivated catalysts was studied. After pretreating the catalysts in a flow of NH <subscript>3</subscript> + SO <subscript>2</subscript> + H <subscript>2</subscript> O + O <subscript>2</subscript> at 200 °C for 24 h, it was observed that the low-temperature SCR (LT-SCR) activity decreased significantly over the 1%VWTi and 5%CeWTi catalysts. For 1%VWTi, NH <subscript>4</subscript> HSO <subscript>4</subscript> (ABS) was the main product detected after the poisoning process. Both of NH <subscript>4</subscript> HSO <subscript>4</subscript> and cerium sulfate species were formed on the poisoned 5%CeWTi catalyst, indicating that SO <subscript>2</subscript> reacted with Ce <superscript>3+</superscript> /Ce <superscript>4+</superscript> , even in the presence of high concentration of NH <subscript>3</subscript> . The decrease of BET specific surface area, NO <subscript>x</subscript> adsorption capacity, the ratio of chemisorbed oxygen, and reducibility were responsible for the irreversible deactivation of the poisoned 5%CeWTi catalyst. Meanwhile, the LT-SCR activity could be recovered over the poisoned 1%VWTi after regeneration at 400 °C, but not for the 5%CeWTi catalyst. For industrial application, it is suggested that the regeneration process can be utilized for 1%VWTi catalysts after a period of time after NH <subscript>4</subscript> HSO <subscript>4</subscript> accumulated on the catalysts.
- Subjects :
- Adsorption
Catalysis
Temperature
Ammonia
Titanium
Subjects
Details
- Language :
- English
- ISSN :
- 1520-5851
- Volume :
- 52
- Issue :
- 12
- Database :
- MEDLINE
- Journal :
- Environmental science & technology
- Publication Type :
- Academic Journal
- Accession number :
- 29781603
- Full Text :
- https://doi.org/10.1021/acs.est.8b01990