The effects of H2O and SO2 on the behaviour of CuSO4-CeO2/TS for low temperature catalytic reduction of NO with NH3.

The catalyst CuSO4-CeO2/TiO2-SiO2 (CuSO4-CeO2/TS), for low temperature catalytic reduction (LT-SCR) of NO with NH was prepared by the impregnation method. The impacts of H2O and SO2 on the catalyst were investigated. Experiments showed that H2O brought down the catalyst's activity at low reaction temperature. However, this negative effect of H2O could be mostly eliminated with a raised temperature of above 220 degrees C. In a 10-hour experiment on the catalyst's resistibility to SO2 poisoning, NO conversion increased slightly by the promoting effect of SO2. The same catalyst underwent continuous examination with both SO2 and H2O in the feed gas; NO conversion of around 90.2% was maintained for 37 hours, showing better performance than CuSO4-CeO2/TiO2. This suggested that SiO2 in the TiO2-SiO2 catalyst supported the supression of the oxidization of SO2 to SO3. Therefore, the formation of ammonium sulphate over the catalyst and the sulphation of CeO2 in the catalyst were greatly alleviated, leading to a better resistibility of the catalyst to SO2 poisioning. After the 37 hours, the catalyst activity began to fall, and an irrecoverable deactivation of the catalyst was observed.