基于Gaussian的瓦斯爆炸微观反应机理

Microcosmic mechanism of gas explosion based on Gaussian

为了从微观热力学和动力学角度揭示瓦斯爆炸机理,应用Gaussian软件,采用密度泛函(DFT)理论的B3LYP/6-31G方法对低温阶段瓦斯爆炸自由基链式反应进行定量分析,优化得到各步反应反应物和产物的稳定构型及相应构型参数,计算得到各反应的反应焓变、吉布斯自由能和活化能等重要参数。结果表明:链引发反应CH4+O2→C H3+H O2进行缓慢,反应焓为259.26kJ/mol,吉布斯自由能为210.68kJ/mol,需吸收大量热量才能激发反应进行。CH 2O+O2→HO2+HCO作为链分支在整个反应中起到至关重要的作用,相应的活化能为193.91kJ/mol,对瓦斯氧化加速达到爆炸有决定性意义。该结论对瓦斯爆炸机理的深层次研究及瓦斯爆炸防治提供了理论依据。

In order to reveal gas explosion reaction mechanism in microcosmic dynamics and thermodynamics ways, the chain reaction of gas explosion at low temperature was quantitatively analyzed by using B3LYP/6-31G methods based on Gaussian. The optimized geometries of reactants and products in the reactions were found. Based on these optimized structures, the reaction enthalpy, Gibbs free energy and the activity energy of all species were obtained. The results show that reaction enthalpy is 259.26kJ/mol and Gibbs free energy is 210.68kJ/mol about the chain initiation CH4＋O2→C^.H3＋HO^.2, which reacts slowly and needs absorbing a mass of heat. The activity energy is 193.91kJ/mol about the reaction CH2O＋O2→HO^.2＋HC^.O, which is playing the key role in providing the reactant HO2 and CHO for reaction of the later stage. And the chain branching reaction demonstrates a decisive significance for gas explosion. The results offer the theoretical basis for studying gas explosion mechanism further and controlling gas explosion.