钒钛基SCR催化剂K中毒酸洗再生研究

Regeneration of K poisoned commercial SCR catalyst by acid washing

以国内某燃煤电厂钒钛基选择性催化还原(SCR)脱硝催化剂为研究对象,对采用浸渍法模拟K中毒的催化剂进行酸洗再生,对再生前后的催化剂进行结构表征,并结合SCR脱硝模拟实验对催化剂表观活性进行评价,分析酸洗对再生催化剂性能的影响。结果表明:酸洗后催化剂活性接近新鲜催化剂,这与催化剂表面吸附氧得到一定程度的恢复有关;酸洗可有效洗去催化剂表面的毒性元素K,而不改变催化剂晶体结构;红外显示Brφnsted酸位是SCR反应NH3的活性吸附位。催化剂经酸洗后酸性位得到部分恢复,但其强度降低,稳定性下降。

The regeneration effect of acid washing on K poisoned SCR catalyst was studied.The experimental catalysts from one power plant in Guangdong province were dipped into KNO3 solution to simulate poisoning.The catalysts before and after regeneration were characterized byvarious methods.Results show that the activity of the catalyst recovered greatly after regeneration,this is partially attributed to the recovery of oxygen adsorbed in the catalyst surface.The toxic element K can be washed away effectively by acid without changing the crystal structure of the catalyst.FTIR results show that Brφnsted acid sites,which was partially recovered after regeneration,are the active chemisorbed sites for NH3 in SCR reaction.However,the stability of regenerated catalyst had declined for the decrease of acid intensity.