Mn-V-Ce/TiO_2低温催化还原NO性能研究

采用浸渍法制备了NH3选择性催化还原(SCR)NO新型催化剂Mn-V-Ce/TiO2,考察了操作条件对其活性的影响;通过NO、O2、NH3的暂态响应实验分析了在该催化剂上进行SCR反应的机理;对催化剂进行了FT-IR和TG分析,探讨了H2O、SO2对其活性的影响。结果表明,该催化剂具有很好的低温SCR活性,空速5 000 h-1、150℃下的NO转化率达99.2%。170℃下同时通硫、水后的350 min内,活性始终保持在98%;单独通入SO2时,中毒速率较快,但体积分数为8%的H2O对该催化剂的活性没有影响,转化率始终保持在98%以上。该催化剂能应用于不含SO2的燃气锅炉烟气和不含SO2的硝酸尾气等NOx工业废气的低温脱硝。

Catalytic reduction of NO over Mn-V-Ce/TiO 2 catalysts at low reaction temperature

A novel Mn-V-Ce/TiO₂ catalyst for selective catalytic reduction (SCR) of nitric oxide was prepared by impregnation method. The effects of reaction temperature, NO and O2 concentrations, NH₃/NO ratio and space velocity on Mn-V-Ce/TiO₂ catalytic activity were studied. The SCR reaction mechanism on this catalyst was explored with transient response reaction of NO, O₂, and NH₃. The effect of H₂O and SO₂ on the catalyst activity was investigated using FT-IR and TG techniques. Experimental results showed that Mn-V-Ce/TiO₂ catalyst has good SCR activity at low temperature. High NO conversion of over 99.2% were observed at 150℃ and space velocity 5000h^－1. When both SO₂ and H₂O were added in feed gas, the NO conversion could be kept over 98% at 170℃ for 350min. However, it was observed that the loss of catalytic activity was quick when SO₂ was added in feed gas alone; while 8% H₂O alone in feed gas had little negative effect on the catalytic activity, which was always over 98% at this situation.The catalyst is expected to be applied in the removal of NOx from exhaust gas without SO2 at low temperature, such as exhaust gas from nitric acid production process or boilers of natural gas.