Mn含量对Mn ZSM-5催化剂脱硝和SO 2氧化性能的影响  

Effect of Mn Content on Denitration and SO2 Oxidation Performance of Mn/ZSM-5 Catalyst

作　　者：肖海平[1] 李建 蒋炎飞 李昕耀 豆朝宗 韩高岩 XIAO Haiping;LI Jian;JIANG Yanfei;LI Xinyao;DOU Chaozong;HAN Gaoyan(School of Energy,Power and Mechanical Engineering,North China Electric Power University,Beijing 102206,China;State Grid Zhejiang Electric Power Research Institute,Hangzhou 310014,China)

机构地区：[1]华北电力大学能源动力与机械工程学院,北京102206 [2]国网浙江省电力有限公司电力科学研究院,浙江杭州310014

出　　处：《环境科学研究》2021年第2期272-278,共7页Research of Environmental Sciences

基　　金：国家自然科学基金项目(No.51206047)。

摘　　要：为研究不同Mn含量对Mn基催化剂上SO2氧化特性的影响,采用湿式浸渍法制备了一系列不同Mn含量的Mn/ZSM-5催化剂,并研究了这些催化剂上SO2的氧化及脱硝特性,利用一系列表征手段研究了Mn/ZSM-5催化剂的物化特性和SO2氧化机理.结果表明:(1)在标准SCR(选择性催化还原)反应中,随着Mn含量和温度的升高,SO2氧化率先增后减,并在300℃时达最大值.(2)在快速SCR反应中,NO2会直接氧化SO2,提高了SO2的氧化率,300℃时SO2氧化率达到最高值(0.76%).(3)脱硝性能试验表明,随着温度的升高,NOx转化率呈先升后降的特征,在快速SCR反应中NO2促进了氧化还原反应的进行,9Mn(Mn含量为9%)催化剂在250℃时NOx转化率达最大值(96.58%),远高于标准SCR反应的NOx转化率.(4)表征结果表明,增加Mn含量提高了晶格氧和Mn4+的含量,使SO2氧化率和NOx转化率均增加;但过高的Mn含量会导致催化剂表面活性物质积聚,导致晶格氧和Mn4+含量下降,从而降低锰基催化剂的氧化还原性能.研究显示,在实际运行温度范围(150~400℃)内,应选择合适的Mn含量的催化剂,保证较高的脱硝效率,降低SO2的氧化率.The effects of Mn content on the SO2 oxidation characteristics of Mn-based catalysts was evaluated by preparing a series of Mn ZSM-5 catalysts with different Mn content using a wet impregnation method.The SO2 oxidation and denitration properties and the physicochemical parameters of these catalysts were examined employing various characterization techniques.The results showed that:(1)During the standard SCR reaction,increasing the Mn content and the initial temperature increased the SO2 oxidation rate to a maximum value at 300℃,above which the rate decreased.(2)During the fast SCR reaction,NO2 directly oxidized SO2,so this compound increased the SO2 oxidation rate.At 300℃,SO2 oxidation reached the highest(0.76%).(3)The NOx conversion rate initially increased and then decreased with increasing temperature.During the fast SCR reaction,the presence of NO2 promoted the redox reaction,and the 9Mn(the mass fraction of Mn loading is 9%)catalyst exhibited the highest NO x conversion rate(96.58%)at 250℃,which is much higher than the NOx conversion rate of the standard SCR reaction.(4)Increasing the Mn loading increased both the lattice oxygen and the Mn 4+concentrations in the material,leading to an increase in the SO2 oxidation rate and NOx conversion rate.However,excessive Mn loading was determined to promote the accumulation of active materials on the catalyst surface while reducing the lattice oxygen and Mn 4+levels.These changes in turn reduced the redox performance of the Mn-based catalyst.In the actual operating temperature range of 150-400℃,a Mn-based supported catalyst should be carefully formulated to ensure high denitration efficiency while minimizing the SO2 oxidation rate.

关 键 词：锰基催化剂 SO 2氧化率 快速SCR反应 脱硝性能 

分 类 号：X511[环境科学与工程—环境工程] TK16[动力工程及工程热物理—热能工程]