活性炭改性整体催化剂上低温选择性还原NO_x  

Selective catalytic reduction of NO_x with NH_3 by monolithic catalyst MnO_x/AC/C under low temperature in the presence of excess O_2.

作　　者：唐晓龙[1] 郝吉明[2] 易红宏[1] 宁平[1] 李俊华[2] 

机构地区：[1]昆明理工大学环境科学与工程学院,云南昆明650093 [2]清华大学环境科学与工程系,北京100084

出　　处：《中国环境科学》2007年第6期845-850,共6页China Environmental Science

基　　金：国家自然科学基金资助项目(20437010);昆明理工大学人才培养基金项目资助(14118052)

摘　　要：采用浸渍法制备活性炭改性整体催化剂（MnOx/AC／C），以NH3为还原剂，考察了反应温度、O2和NO体积分数等不同条件下低温选择性催化还原NOx性能，并采用XRD、TPD和BET等测试手段对催化剂进行表征．结果表明，MnOx在载体表面呈高度分散，堇青石负载了活性炭层和MnOx后，整体催化剂的比表面积增至88．7m。／g；NO吸附量显著提高，150℃NO转化率〉50％,NO转化率在220℃时达最大值97％，200-280℃均高于80％；在低温时提高反应气氛中的O2和NO体积分数均可明显提高NO转化率；在确保活性组分分散度的前提下提高MnOx负载量将利于进一步提高催化剂的低温催化活性；反应140h后整体催化剂炭层氧化损失率仅为1.25％，具有较好的稳定性．MnOx/AC/C monolithic catalysts were prepared by impregnation AC/C with aqueous solutions of Mn（NO3）2. The selective catalytic reduction （SCR） activities of monolithic catalysts for NOx with NH3 were tested in various conditions, and the activity variation under different experimental conditions were investigated. The BET specific area of MnOx/AC/C was about 88.7m^2/g, while the bared ceramic support was only 5m^2/g, and the adsorption of NO on MnOx/AC/C enhanced greatly. The data of XRD of crushed samples showed that MnOx were in good dispersion over the catalysts. MnOx/AC/C monolithic catalysts showed better activity at low temperature range than traditional vanadium type catalysts. NO conversion reached 50% even at 150℃, and more than 80% occurred in the range of 200-280℃. The maximum NO conversion 97% was observed at 220℃. The NO conversion could be improved by enhancing the concentration of O2 and NO in the feed gas. Besides, trying to get a better balance between the loading amount and dispersion of MnOx over AC/C was benefit to NO reduction. The stability of the monolithic catalyst was well and the loss of AC was only 1.25% after 140h test.

关 键 词：整体催化剂 氮氧化物 氨 选择性催化还原(SCR) 低温 

分 类 号：X511[环境科学与工程—环境工程]