水溶剂效应对煤氧化特性的影响  

Influence of water solvent effect on oxidation characteristics of coal

作　　者：邓存宝[1] 戴凤威[1] 邓汉忠[2] 武司苑 

机构地区：[1]辽宁工程技术大学安全科学与工程学院,辽宁阜新123000 [2]辽宁工程技术大学材料科学与工程学院,辽宁阜新123000

出　　处：《中国安全生产科学技术》2016年第3期88-93,共6页Journal of Safety Science and Technology

基　　金：国家自然科学基金项目(51274112;51174108);国家科技支撑计划项目(2013BAK06B07-2)

摘　　要：水既可以隔绝空气,又可以吸热降温,是防火、灭火的绝好材料。但经过大量的煤矿现场应用及实验研究发现:很多情况下,注水不仅不能预防煤炭自燃灾害,反而易于灾害发生。为了揭示煤矿井下注水易引起煤自燃的原因,应用Gaussian09程序,采用含时密度泛函理论(TD-DFT),在B3LYP/6-31G(d,p)水平上,分析水溶剂效应对煤氧化特性的影响。由计算结果可知:煤各模型的HOMO与O2的LUMO对称性相同,且能级差均小于0.4 e V,符合前线轨道理论提出的反应条件,所以煤HOMO轨道的电子将流向O2未占据的LUMO轨道,从而发生氧化反应,氧化反应剧烈时将引起煤炭自燃;当煤浸泡在水中,煤分子与水分子间将产生静电相互作用,氢键及孔洞能等相互作用,这些相互作用影响了煤分子的核外电子排布,改变了煤的前线轨道能级,煤各模型的HOMO与O2的LUMO能级差比在气相中更小,因此,被水浸泡的煤更容易发生氧化自燃。Water is a good material for fire prevention and extinguishment,which plays the roles of air isolation and heat absorbing for cooling. However,after a large number of field application in coal mine and experimental research,it was found that in many cases,water injection not only cannot prevent the spontaneous combustion of coal,but also be vulnerable to the occurrence of accident. In order to reveal the reason that water injection is easy to cause the spontaneous combustion of coal,through using the Gaussian 09 program,the influence of water solvent effect on oxidation characteristics of coal was analyzed by adopting the time- dependent density functional theory（ TD- DFT） at the B3 LYP / 6- 31G（ d,p） levels. The results showed that the highest occupied molecular orbital（ HOMO） of each coal model and the lowest unoccupied molecular orbital（ LUMO） of O2 have the same symmetry,and both the energy difference are less than 0. 4e V,which are in accord with the reaction conditions proposed by frontier orbital theory. So the electrons on HOMO orbit of coal flow to the unoccupied LUMO orbit of O2,then the oxidation reaction occurs. When the oxidation reaction is intense,it will cause the spontaneous combustion of coal. When coal is soaked in water,electrostatic interaction,hydrogen bond,cavity formation energy and other interactions are produced between coal molecule and water molecule. These interactions will influence the extranuclear electron configuration of coal molecule,and change the frontier orbital energy levels of coal. The energy difference between the HOMO of every coal model and the LUMO of O2 is smaller than that in the gas phase,therefore,oxidation and spontaneous combustion are easy to occur for coal soaked in water.

关 键 词：煤 氧化性 水 溶剂效应 

分 类 号：X936[环境科学与工程—安全科学]