结合TG-TDLAS与ReaxFF MD的烟煤热解CH₄生成机理研究OA

To elucidate the mechanism of methane(CH₄)formation during bituminous coal pyrolysis at the atomic scale,addressing the limitations of traditional experimental methods in capturing reaction pre⁃cursors and microscopic pathways,this study employed a combined approach of thermogravimetric-tune⁃able diode laser absorption spectroscopy(TG-TDLAS)experiments and reaction molecular dynamics sim⁃ulations(ReaxFF MD).First,TG-TDLAS experiments were conducted to obtain the macroscopic tem⁃perature dependence and kinetic behavior of CH₄ generation.Second,based on elemental analysis,infra⁃red spectroscopy,and ¹³C NMR characterization of bituminous coal samples,a molecular model(C₃₀₉H₂₀₃N₃O₁₈)was constructed.ReaxFF MD simulations analyzed the dynamic reaction processes of CH₃ radical cleavage,hydrogen migration,and CH₄ formation at different temperatures.Results indicate that experi⁃mentally measured CH₄ production peaks around 600 ℃ within the 450–750 ℃ range.Simulations reveal the microscopic mechanism:side-chain CH₃ fragments at approximately 1 100 K to form radicals,which subsequently convert to CH₄ by abstracting adjacent hydrogen atoms,peaking at 2 500 K.Both measure⁃ments show high consistency in production trends.The conclusion asserts that this method systematically elucidates,from both macroscopic and microscopic perspectives,that CH₄ generation stems from the equi⁃librium process between precursor fragmentation and hydrogen abstraction.It validates the unique advan⁃tage of ReaxFF MD in revealing the behavior of intermediates within the complex reaction network of coal pyrolysis,providing a theoretical basis for understanding coal spontaneous combustion,pyrolysis path⁃ways,and enhancing energy conversion efficiency.