诱发煤炭自燃的活性基团排序图谱

Chemical structures of active groups in coal are complicated, their oxidation processes and reaction energies will also change with different structural characteristics. The laws of chemical structures effecting oxidation reaction are a crux about revealing the secret of coal spontaneous combustion. Firstly, Active groups and their structural characteristics of all spontaneous combustion coal will be systematically identified using extraction, infrared, mass spectrometry and other experimental methods. Secondly, the laws will be explored that coal chemical structures effect the oxidation reaction of active groups using density functional theory, and the interaction mechanism of all active groups in coal and O2 will be studied with the effect laws, and the activation energy, released heat and primary product (it is the newly formed active group and gas) of every active group oxidation reaction will be got, so the evolution sequence of active groups can be deciphered that is occurred in coal spontaneous combustion process. Then, sequence map of active groups induced coal spontaneous combustion will be set up like gene map, which is appropriate for all kind of spontaneous combustion coal, and can be used to analysis the process of coal spontaneous combustion. According to the map, the activation energies of coal oxidation reaction can be calculated, the difficulties of coal spontaneous combustion can be decide, the coal spontaneous combustion period can be forecasted with the actual conditions, the research subjects of needing modified activity can be determined to dispense inhibitor, and so on, which will provide theoretical basis and technical support for coal spontaneous combustion fire prevention project.

煤中活性基团的化学结构形态复杂，结构特征不同，氧化反应历程与反应能量也会发生改变，其影响规律是目前揭示煤炭自燃奥秘的症结所在。本项目拟应用萃取、红外、质谱等实验方法，对所有易自燃煤种的活性基团及其结构特性进行系统的辨识；采用密度泛函理论，探寻煤化学结构特征对活性基团氧化反应的影响及规律，结合该影响规律，在同一水平下，剖析煤的所有活性基团与O2化合演变机制，得到各活性基团氧化反应活化能、放热量及其一级产物（即新形成的活性基团和产生的气体）等，破译煤炭自燃过程中活性基团演变序列，像基因图谱那样，构建一个适用于所有自燃煤种的，解析煤炭自燃过程的，煤中所有活性基团与O2化合演变机制信息汇总图谱——诱发煤炭自燃的活性基团排序图谱。根据该图谱计算煤炭氧化反应活化能，判定煤炭自燃难易，结合现场实际条件，预测煤炭自然发火期，确定阻化改性研究对象，配制阻化剂等，为煤炭自燃防灭火工程提供理论依据与技术支持。

煤分子的组成成分种类多、结构复杂化以及无机物的催化或阻化作用不明，导致煤炭自燃诱因难辨。煤的个别活性基团氧化特性不能代表煤的整体特性，活性基团化学结构特征和数量对于分析煤的自燃特性同样至关重要。本项目利用红外、XPS等实验定量分析了煤活性基团种类和数量；搜集了大量煤成分研究资料，归纳总结了煤分子的化学结构特性；采用量子化学理论，分析了煤的所有活性基团与O2反应机理，并分析了化学结构特征对活性基团氧化机理的影响。结果表明：煤活性基团氧化去氢反应活性较大，碳原子上的氢原子数目越少越容易氧化，没有氢原子的碳难氧化；直链型含次甲基的基团组合-CH-CH2-、-CH-CH3、-CH-CH-为易氧化基团，活化能分别为50.27 kJ/mol、52.75 kJ/mol、56.77 kJ/mol，其次是直链型含亚甲基的基团组合-CH2-CH2-、-CH2-CH3（属于氧化基团，活化能分别为68.68 kJ/mol和74 kJ/mol），同时羟基、氨基和硫醚为极易氧化基团（活化能均低于次甲基基团组合），吡啶和吡咯为易吸附型活性基团。但由于煤中这些活性基团含量极少，对煤样氧化反应活化能影响不大。整理所有活性基团氧化信息，绘制了诱发煤炭自燃活性基团排序图谱。利用该图谱，结合煤样活性基团定量结果，通过加权平均法可以求得煤样氧化反应活化能。计算结果与以上分析结论基本吻合，煤样活化能主要受脂肪型次甲基和亚甲基含量影响。诱发煤炭自燃的活性基团排序图谱可以作为一下通用工具，辅助推测任何煤样的氧化反应活化能，这对煤矿防火工程建设意义重大。