碱金属离子对吡咯热解生成NO_x前驱物HCN机理的影响  

Effect of alkali metal ions on the formation mechanism of HCN as NO_x precursor during pyrrole pyrolysis

作　　者：刘吉[1] 陆强[1] 蒋晓燕[1] 胡斌[1] 董长青[1] 杨勇平[1] LIU Ji;LU Qiang;JIANG Xiaoyan;HU Bin;DONG Changqing;YANG Yongping(National Engineering Laboratory for Biomass Power Generation Equipment,North China Electric Power University,Beijing 102206,China)

机构地区：[1]华北电力大学生物质发电成套设备国家工程实验室,北京102206

出　　处：《煤炭学报》2018年第9期2633-2638,共6页Journal of China Coal Society

基　　金：国家重点基础研究发展计划(973)资助项目(2015CB251501);北京市科技新星资助项目(Z171100001117064);煤燃烧国家重点实验室开放基金资助项目(FSKLCCA1706)

摘　　要：为了解碱金属离子对煤热利用过程中NO_x污染物形成的影响,针对煤中含氮模型化合物吡咯,在吡咯常规非催化热解机理的研究基础上,采用密度泛函理论B3LYP/6-31+G(d,p)方法,研究了碱金属离子(Na^+,K^+)对吡咯催化热解反应机理和路径的影响。结果表明,碱金属离子能显著促进吡咯热解生成HCN路径中的内部氢转移反应、协同开环反应和协同裂解反应的发生,但对分子异构化反应的影响较小。Na^+和K^+均能降低吡咯热解生成HCN决速步的活化能,从而可促进HCN的形成,且两种碱金属离子的催化作用能力为Na^+>K^+。Pyrrole is selected as the N-containing model compound for the investigation of the effect of alkali metal ions(Na^+,K^+)on NOx formation during coal thermal utilization process.Based on conventional non-catalytic mechanism studies,the density functional theory(DFT)method and B3LYP/6-31+G(d,p)basis set are adopted to elucidate the pyrolysis mechanism and pathways of pyrrole.The calculation results indicate that both Na^+and K^+show significant effects on the internal hydrogen transfer,ring-opening and concerted decomposition reactions,while rarely influence the internal hydrogen isomerization reaction.It is found that the alkali metal ions(Na^+and K^+)can promote the formation of HCN from pyrrole through decreasing the activation energy of the rate-determining step.In addition,Na+exhibits a better catalytic activity than K^+.

关 键 词：吡咯 热解机理 密度泛函理论 碱金属离子 HCN 

分 类 号：TQ530[化学工程—煤化学工程]