褐煤低温氧化分子结构单元变化特性  

Variation characteristics of molecular structure unit during lowtemperature oxidation of lignite coal

作　　者：姬玉成 张英华[1] 黄志安[1,2,3,4] 邵振鲁 高玉坤[1] 肖善林[1] JI Yucheng;ZHANG Yinghua;HUANG Zhi′an;SHAO Zhenlu;GAO Yukun;XIAO Shanlin(State Key Laboratory of High-Efficient Mining and Safety of Metal Mines,Ministry of Education,University of Science and Technology Beijing,Beijing 100083,China;Key Laboratory of Gas and Fire Control for Coal Mines,Ministry of Education,China University of Mining and Technology,Xuzhou 221116,China;State Key Laboratory Cultivation Base for Gas Geology and Gas Control,Henan Polytechnic University,Jiaozuo 454000,China;Work Safety Key Lab on Prevention and Control of Gas and Roof Disasters for Southern Coal Mines,Hunan University of Science and Technology,Xiangtan 411201,China)

机构地区：[1]北京科技大学,金属矿山高效开采与安全教育部重点实验室,北京100083 [2]中国矿业大学,煤矿瓦斯与火灾防治教育部重点实验室,江苏徐州221116 [3]河南理工大学,河南省瓦斯地质与瓦斯治理重点实验室—省部共建国家重点实验室培育基地,河南焦作454000 [4]湖南科技大学,南方煤矿瓦斯与顶板灾害预防控制安全生产重点实验室,湖南湘潭411201

出　　处：《中南大学学报（自然科学版）》2020年第9期2614-2623,共10页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51974015,51904292,51474017);中国矿业大学煤矿瓦斯与火灾防治教育部重点实验室开放基金资助项目(2017CXNL02);河南理工大学河南省瓦斯地质与瓦斯治理重点实验室—省部共建国家重点实验室培育基地开放基金资助项目(WS2018B03);湖南科技大学南方煤矿瓦斯与顶板灾害预防控制安全生产重点实验室开放基金资助项目(E21724)。

摘　　要：为了进一步揭示煤自燃微观反应机理,通过电子自旋共振试验和傅里叶红外光谱试验,对褐煤氧化升温过程中自由基和官能团等分子结构单元的变化进行研究,并对两者的反应路径进行量子化学分析。研究结果表明:在氧化升温过程中,自由基浓度持续增长,220℃时显著增大85.6%,说明低温氧化阶段自由基产生量大于消耗量,自由基总量增加可以提高反应体系的反应活性;过渡产物-COOH含量呈近似指数型增长,220℃时增加72.3%,游离态·OH、氢键自缔合-OH和酚、醇、羧酸-OH这3种基团含量均逐渐降低,20~60℃时是快速降低区;煤中官能团等结构单元与氧气间的链式反应有2种反应路径,即线性路径和交叉/循环路径;线性反应路径通过羟基自由基等关键基团参与的多活性链式位点反应转换到交叉/循环反应路径,这种转换将加快煤自燃反应进程;特定官能团的含量变化是该官能团在不同反应路径中参与的多个反应序列竞争结果的体现,反映了官能团在煤自燃过程中的不同反应机制。In order to further reveal the microscopic reaction mechanism of spontaneous combustion,the variation of free radicals and functional groups of lignite coal samples in the dynamic heating process were investigated by ESR and FT-IR test,and the transformation path of them was analyzed by quantum chemistry method.The results show that,during the process of oxidation and heating,the concentration of free radicals of lignite significantly increases by 85.6%at 220℃,indicating that during the low-temperature oxidation stage,the free radical production is greater than consumption,and the cumulative free radicals can improve the reactivity of the reaction system.The content of intermediate product-COOH increases approximately exponentially by 72.3%at 220℃.The content of three groups(·OH in free state,-OH of hydrogen bond self-association and-OH of phenol,alcohol,carboxylic acid)gradually reducs,and the rapid decline zone is 20−60℃.The complex chain reaction between free radicals/functional groups and oxygen shows two reaction path,namely linear path and cross/cyclic path.Linear path transfers to cross/cyclic path through the chain reaction of multiple active sites,which is triggered by hydroxyl radicals.The variation of the content of certain functional group is the consequence of the competition of several reaction sequences that the functional group participates in different reaction paths,which reveals the different chemical mechanisms of functional groups in coal spontaneous combustion.

关 键 词：自由基 官能团 氧化 升温 量子化学 

分 类 号：TD752[矿业工程—矿井通风与安全]