W0_(3) -ZrO_(2)/TiO_(2) -CeO_(2) -MnO_(2)选择性催化还原NO热动力学和反应机理研究  

Kinetics and reaction mechanism of selective catalytic reduction of NO by WO_(3)-ZrO_(2)/TiO_(2)-CeO_(2)-MnO_(2)

作　　者：宋静 金奇杰 计雯钰 徐慕涛 戴毅 徐海涛 SONG Jing;JIN Qijie;JI Wenyu;XU Mutao;DAI Yi;XU Haitao(Nanjing Jiekefeng Environmental Protection Technology Equipment Research Institute Co.,Ltd.,Nanjing 210031,China;Nanjing University of Technology,Nanjing 211816,China)

机构地区：[1]南京杰科丰环保技术装备研究院有限公司,江苏南京211106 [2]南京工业大学环境科学与工程学院,江苏南京211816

出　　处：《电力科技与环保》2022年第1期10-17,共8页Electric Power Technology and Environmental Protection

基　　金：江苏省重点研发计划(BE2018074);南京市科技顶尖专家集聚计划;江苏省国际合作项目(BZ2021018);苏州市科技计划(SGC2020092);江苏省“333高层次人才培养工程”;江苏省优势学科(PAPD)。

摘　　要：工业治理氮氧化物主要应用的是高效稳定的选择性催化还原(selective catalytic reduction,SCR)脱硝技术,为了研究面向垃圾焚烧行业的烟气脱硝催化剂,采用共沉淀法与浸渍法联用,制备得到了WO_(3)-ZrO_(2)/TiO_(2)-CeO_(2)-MnO_(2)催化剂用于NH 3-SCR,研究其热动力学并计算得到其活化能。结果表明,对于WO_(3)-ZrO_(2)/TiO_(2)-CeO_(2)-MnO_(2)催化剂,内外扩散近似消除的条件为:颗粒粒径为0.25~0.38 mm,催化剂质量为0.1~0.2 g,气体流速在667~1000 mL/min。在此条件下,WO_(3)-ZrO_(2)/TiO_(2)-CeO_(2)-MnO_(2)催化剂脱硝时O_(2)和NH_(3)的反应级数均是0级,NO的反应级数是1级。WO_(3)-ZrO_(2)/TiO_(2)-CeO_(2)-MnO_(2)催化剂的表观反应活化能为33.3 kJ/mol,相对低于现有不同催化剂体系的表观反应活化能,因此,其具有优异的NH_(3)-SCR脱除NO的活性。与此同时,低温下-NH^(*)_(2)与单齿亚硝酸盐和双齿硝酸盐反应,生成N_(2)和H_(2)O,遵循Langmuir-Hinshelwood(L-H)机理;同时,NH^(+)_(4)与气相NO发生反应,生成N_(2)和H_(2)O,遵循Eley-Rideal(E-R)机理。高温下主要是NH^(+)_(4)与气相NO快速发生反应,生成N_(2)和H_(2)O,遵循E-R机理。因此,WO_(3)-ZrO_(2)/TiO_(2)-CeO_(2)-MnO_(2)催化剂在低温下同时遵循E-R和L-H机理,而在高温下主要遵循E-R机理。At present,the main application of industrial treatment of NO_(x) is efficient and stable selective catalytic reduction(SCR)denitration technology.In order to study the denitrification catalyst for waste incineration industry,WO_(3)-ZrO_(2)/TiO_(2)-CeO_(2)-MnO_(2)catalyst is prepared by co-precipitation method combines with impregnation method for selective catalytic reduction of NO.The thermodynamics are investigated and its activation energy is calculated.Results show that for WO_(3)-ZrO_(2)/TiO_(2)-CeO_(2)-MnO_(2)catalyst,the conditions for approximate elimination of internal and external diffusion are:particle size of 0.25~0.38 mm,catalyst mass of 0.1~0.2 g,and gas flow rate of 667~1000 mL/min.Under these conditions,when WO_(3)-ZrO_(2)/TiO_(2)-CeO_(2)-MnO_(2)catalyst is used for NH_(3)-SCR,the reaction order of O_(2)and NH_(3) was 0,and the reaction order of NO is 1.It is found that apparent reaction activation energy of WO_(3)-ZrO_(2)/TiO_(2)-CeO_(2)-MnO_(2)catalyst is 33.3 kJ/mol,which is relatively lower than apparent reaction activation energy of different existing catalysts.Therefore,it has excellent catalytic performance for NH_(3)-SCR.Meanwhile,-NH^(*)_(2)reacts with monodentate nitrite and bidentate nitrate at low temperature to generate N_(2)and H_(2)O,so it follows the Langmuir-Hinshelwood(L-H)mechanism.NH^(+)_(4)reacts with gas phase NO to generate N_(2)and H_(2)O,and it follows Eley-Rideal(E-R)mechanism.At high temperature,NH^(+)_(4)reacted quickly with gas phase NO to generate N_(2)and H_(2)O,so that follows E-R mechanism.Therefore,WO_(3)-ZrO_(2)/TiO_(2)-CeO_(2)-MnO_(2)catalyst simultaneously follows E-R and L-H mechanisms at low temperatures,and mainly follows E-R mechanism at high temperatures.

关 键 词：氮氧化物 催化还原 金属氧化物 热力学 活化能 反应机理 高温 稀土 

分 类 号：TK16[动力工程及工程热物理—热能工程] X705[环境科学与工程—环境工程]