Laboratory Investigation of Selective Catalytic Reduction Catalysts: Deactivation by Potassium Compounds and Catalyst Regeneration
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- 作者：Yuanjing Zheng ; Anker Degn Jensen ; and Jan Erik Johnsson
- 刊名：Industrial & Engineering Chemistry Research
- 出版年：2004
- 出版时间：February 18, 2004
- 年：2004
- 卷：43
- 期：4
- 页码：941 - 947
- 全文大小：129K
- 年卷期：v.43,no.4(February 18, 2004)
- ISSN：1520-5045
文摘
The deactivation and regeneration of selective catalytic reduction (SCR) catalysts poisoned bypotassium by a wet-impregnation method was investigated experimentally. Potassium in theform of both chloride and sulfate is a strong poison for the catalyst. The results indicate thatpotassium titrates the active sites for NH3 adsorption. Simply increasing the operatingtemperature or the vanadium content in the catalyst cannot compensate the loss of catalystactivity: Increasing the temperature hardly increases the conversion of NO for the stronglypoisoned catalysts, and catalysts with high vanadium content become active for oxidizing NH3to NO, causing a net NO formation. Deactivated catalysts can be regenerated by differentmethods. Sulfation by gaseous SO2 is efficient provided the poison is first removed by washing.When regenerating by 0.5 M H2SO4, the catalyst regains a higher activity than that of the freshcatalyst at temperatures higher than 300 
C. Heat treatment of the catalyst at 400 C for 2 hafter poisoning to simulate actual operation has no influence on the regeneration by 0.5 M H2SO4.Deactivated catalysts without the heat treatment step regain higher activities than that of thefresh catalyst at all temperatures when regenerated by 1 M NH4Cl. However, the heat treatmentstep has a negative effect on the regeneration by NH4Cl.
C. Heat treatment of the catalyst at 400 C for 2 hafter poisoning to simulate actual operation has no influence on the regeneration by 0.5 M H2SO4.Deactivated catalysts without the heat treatment step regain higher activities than that of thefresh catalyst at all temperatures when regenerated by 1 M NH4Cl. However, the heat treatmentstep has a negative effect on the regeneration by NH4Cl.