MnO_(x)/Ce-ZrO_(2)低温SCR催化剂的镁中毒及再生实验  

Experimental study on magnesium poisoning and regeneration of MnO_(x)/Ce-ZrO_(2)low-temperature SCR catalyst

作　　者：安风霞 陈辉 张强 AN Fengxia;CHEN Hui;ZHANG Qiang(China Energy Science and Technology Research Insititute Co.,Ltd.,Nanjing,210023,China;College of Energy and Environment,Southeast University,Nanjing,210096,China)

机构地区：[1]国家能源集团科学技术研究院有限公司,南京210023 [2]东南大学能源与环境学院,南京210096

出　　处：《环境化学》2025年第3期1074-1082,共9页Environmental Chemistry

基　　金：国家重点研发专项(2022YFC3701504)资助.

摘　　要：锰基氧化物在低温下去除NO的高活性和高选择性得到了较多的研究,MnO_(x)/Ce-ZrO_(2)低温催化剂具有很好的抗H_(2)O和SO_(2)性能,但烟气中存在的碱土金属(Mg、Ca)会造成催化剂的中毒.为了深入探究碱土金属(Mg)对催化剂性能的影响和中毒催化剂的再生机理,并进一步对中毒催化剂进行再生实验,探究其再生机理,采用共沉淀法制备了MnO_(x)/Ce-ZrO_(2)催化剂,并用浸渍法模拟不同负载量的碱土金属Mg对催化剂中毒程度的影响.结果表明,Mg的添加会导致催化剂中毒,且负载量越大,中毒程度越深.运用BET、XRD、H_(2)-TPR、NH_(3)-TPD、XPS等手段对新鲜催化剂和中毒催化剂进行了表征.结果表明,虽然Mg中毒后的催化剂晶型未发生变化,但其比表面积和Lewis酸位酸量降低、氧化还原能力减弱、表面吸附氧浓度减少,导致催化剂的失活.对Mg负载量为0.2的催化剂的再生实验表明,酸洗后脱硝活性有了很大程度的恢复,在180℃之后甚至超过了新鲜催化剂的效率.BET和NH_(3)-TPD结果表明,酸洗之后的中毒催化剂的比表面积和表面酸度基本恢复到新鲜催化剂的水平,这是催化剂活性恢复的主要原因.The high activity and high selectivity of manganese-based oxides in removing NO at low temperature have been studied.MnO_(x)/Ce-ZrO_(2)low temperature catalyst has good anti-H_(2)O and SO_(2)performance,but the alkali soil metals(Mg,Ca)existing in flue gas will cause the poisoning of catalyst.In order to further explore the influence of alkali soil metal(Mg)on the performance of catalyst,and the regeneration mechanism of poisoning catalyst,and further explore the regeneration mechanism,MnO_(x)/Ce-ZrO_(2)catalyst was prepared by precipitation method,and the influence of alkali soil metal Mg on the degree of poisoning.The results showed that the addition of Mg can cause catalyst poisoning,and the deeper the load is.BET,XRD,by other means,H_(2)-TPR,NH_(3)-TPD,XPS and so on.The results showed that although the crystal form of the catalyst did not change after Mg poisoning,its specific surface area and Lewis acid amount,reduced redox capacity,and reduced surface adsorbed oxygen concentration led to the inactivation of the catalyst.Regeneration experiments with the catalyst with a Mg load of 0.2 showed a substantial recovery of denitrification activity after acid wash,even exceeding the efficiency of the fresh catalyst after 180℃.BET and NH_(3)-TPD results show that the specific surface area and surface acidity of the poisoned catalyst are basically restored to the level of fresh catalyst,which is the main reason for the recovery of catalyst activity.

关 键 词：SCR 催化剂 失活 中毒 再生 碱土金属. 

分 类 号：X-1[环境科学与工程] O6[理学—化学]