LaMnO_(3)/生物炭催化剂低温NH_(3)-SCR催化脱硝性能研究  

Study on the catalytic denitrification performance of low-temperature NH_(3)-SCR over LaMnO_(3)/biochar catalyst

作　　者：范孝雄 郝丽芳[1] 范垂钢[1] 李松庚[1] FAN Xiaoxiong;HAO Lifang;FAN Chuigang;LI Songgeng(State Key Laboratory of Multi-phase Complex System,Institute of Process Engineering,Chinese Academy of Science,Beijing 100190,China;Sino Danish College,University of Chinese Academy of Science,Beijing 100049,China)

机构地区：[1]中国科学院过程工程研究所多相复杂系统国家重点实验室,北京100190 [2]中国科学院大学中丹学院,北京100049

出　　处：《化工学报》2023年第9期3821-3830,共10页CIESC Journal

基　　金：国家重点研发计划项目(2019YFC1906704);国家自然科学基金项目(21978305)。

摘　　要：以La-Mn钙钛矿氧化物为活性组分,生物炭为载体,利用浸渍法制备负载型脱硝催化剂LMO/BCNA。利用固定床反应装置考察了催化剂的催化活性以及耐硫耐水性能,100~250℃范围内,NO转化率>80%,N2选择性>90%,225℃时NO转化率最高,为95.8%,对应的N2选择性为95.4%。与氧化物相比,负载型催化剂的催化活性大幅提升,同时也扩宽了工作温度区间;生物炭载体的引入,减弱了催化剂对H2O、SO_(2)的吸附,增强了耐硫耐水性能。应用稳态动力学方法构建催化反应动力学模型,在实验条件范围且O_(2)含量为5%时,催化NH_(3)-SCR反应过程中NO、O_(2)、NH_(3)的反应级数分别为0.66、0、0,并得到LMO/BCNA催化的反应活化能为25.52 kJ/mol,低于商用钒钨钛催化剂的化学反应活化能(40~94 kJ/mol)。Selective catalytic reduction with ammonia(NH_(3)-SCR)is one of the most widely adopted technology to reduce the emission of nitrogen oxides.The activity and stability of catalyst plays a major role in the denitration process,and the increasing requirements for low working temperature,strong SO_(2)/H2O resistance capability have stimulated the development of new type NH_(3)-SCR catalyst.In this work,La-Mn perovskite oxide as active component and porous biochar as support were introduced to a biochar-supported catalyst,LMO/BCNA.The catalytic performance and SO_(2)/H2O resistance of catalysts was tested in a fixed bed reactor.NO conversion achieved over 80%and N2 selectivity was over 90%within the temperature range of 100—250℃,and the highest NO conversion reached 95.8%with N2 selectivity of 95.4%at 225℃.Compared to LMO,LMO/biochar catalyst significantly improved denitration efficiency and widened working temperature window due to the synergistic catalytic effect of biochar.The introduction of biochar carrier weakens the catalyst’s adsorption of H2O and SO_(2),and enhances sulfur and water resistance.The kinetic model was built based on steady-state dynamics.On the test conditions and the presence of 5%O_(2),the NH_(3)-SCR reaction order with respect to NO,O_(2)and NH_(3)was 0.66,0 and 0,respectively.Accordingly,the activation energy for LMO/BCNA was 25.52 kJ/mol,which was much lower than that for commercial vanadium-wolframium-titanium catalysts of 40—94 kJ/mol.

关 键 词：脱硝 生物炭 钙钛矿氧化物 选择性催化还原 稳态动力学 

分 类 号：X511[环境科学与工程—环境工程]