Variation characteristics of molecular structure unit during low-temperature oxidation of lignite coal

被引：0
|
作者：
Ji Y. [1 ]
Zhang Y. [1 ]
Huang Z. [1 ,2 ,3 ,4 ]
Shao Z. [2 ]
Gao Y. [1 ]
Xiao S. [1 ]
机构：
[1] State Key Laboratory of High-Efficient Mining and Safety of Metal Mines, Ministry of Education, University of Science and Technology Beijing, Beijing
[2] Key Laboratory of Gas and Fire Control for Coal Mines, Ministry of Education, China University of Mining and Technology, Xuzhou
[3] State Key Laboratory Cultivation Base for Gas Geology and Gas Control, Henan Polytechnic University, Jiaozuo
[4] Work Safety Key Lab on Prevention and Control of Gas and Roof Disasters for Southern Coal Mines, Hunan University of Science and Technology, Xiangtan
来源：
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | 2020年 / 51卷 / 09期
基金：
中国国家自然科学基金;
关键词：
Free radicals; Functional groups; Heating process; Oxidization; Quantum chemistry;
D O I：
10.11817/j.issn.1672-7207.2020.09.027
中图分类号：
学科分类号：
摘要：
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. © 2020, Central South University Press. All right reserved.
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页码：2614 / 2623
页数：9
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