内蒙古褐煤大分子结构模型优化与高温燃烧机理的分子动力学模拟研究  

Molecular dynamics simulation study on optimisation of macromolecular structure model and high-temperature combustion mechanism of Inner Mongolia lignite

作　　者：贾进章[1,2] 田昊 贾鹏 赵丹 王东明 宋海龙[1,2] JIA Jinzhang;TIAN Hao;JIA Peng;ZHAO Dan;WANG Dongming;SONG Hailong(College of Safety Science and Engineering,Liaoning Technical University,123000 Fuxin,China;Key Laboratory of Mine Thermo-motive Disaster and Prevention,Ministry of Education,Liaoning Technical University,123000 Fuxin,China;Faculty of Civil Engineering and Architecture,Zhanjiang University of Science and Technology,524000 Zhanjiang,China)

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]辽宁工程技术大学矿山热动力灾害与防治教育部重点实验室,辽宁阜新123000 [3]湛江科技学院建筑工程学院,广东湛江524000

出　　处：《煤炭转化》2025年第2期35-46,共12页Coal Conversion

基　　金：国家自然科学基金项目(52174183,52374203);辽宁省博士科研启动基金计划项目(2023-BS-203).

摘　　要：在分子水平上了解褐煤的高温燃烧机理是至关重要的。通过工业分析和元素分析,XPS,^(13)C NMR核磁共振实验和表征数据构建了内蒙古褐煤大分子结构模型并对其进行了结构优化,基于反应力场分子动力学(ReaxFF MD)模拟,利用AMS软件研究了其在2500 K~4000 K高温下的燃烧行为,重点分析了4000 K高温下的燃烧特性。通过ReaxFF MD的模拟结果得出了褐煤高温燃烧过程中的主要气体和自由基产物的反应占比,确定了褐煤高温燃烧的主要气相产物(CO_(2),CO,H_(2)O,O_(2))和活性物种(·O,·H,·OH,·CHO,·CH_(2)O,·CHO_(2))。通过MS软件的Dmol^(3)模块,重点分析了主要燃烧产物的静电式分布和扩散特性。结果表明:内蒙古褐煤的燃烧过程包括多种复杂的物理化学相互作用;通过静电势分布和扩散特性分析发现,自由基在燃烧链反应中生成和消耗对燃烧过程的维持至关重要(特别是·OH和·H),电势分布显示出明显的高活性特征,扩散特性表现出高扩散性和高迁移性,表明高温环境下的扩散和反应活性对燃烧效率和链反应的延续起到了关键作用,进一步揭示高温可以有效促进自由基的生成和消耗,从而优化燃烧效率并减少污染物的生成。ABSTRACT It is crucial to understand the high temperature combustion mechanism of lignite at the molecular level.In this study,the macromolecular structure model of lignite from Inner Mongolia was constructed and structurally optimized through proximate and ultimate analyses,XPS,and ^(13)C NMR experimental data,and the combustion behavior of lignite was investigated at high temperatures of 2500 K−4000 K based on reactive force field molecular dynamics(ReaxFF MD)simulations using AMS software with a focus on combustion properties at 4000 K.The combustion characteristics at 4000 K were analyzed,and the reaction percentages of the main gases and radical products in the high-temperature combustion process of lignite were derived from the simulation results of ReaxFF MD and,the main gas-phase products(CO_(2),CO,H_(2)O,and O_(2))and reactive species(·O,·H,·OH,·CHO,·CH_(2)O,and·CHO_(2))in the high-temperature combustion of lignite were determined.The electrostatic distribution and diffusion characteristics of the main combustion products were analyzed by focusing on the Dmol^(3) module of MS software.The results indicate that the combus tion process of Inner Mongolia lignite includes a variety of complex physicochemical interactions.Through the analysis of electrostatic potential distribution and diffusion characteristics,it was found that the generation and consumption of free radicals in the combustion chain reaction are crucial for the maintenance of the combustion process,especially for the·OH and·H radicals.The potential distribution show obvious high-activity characteristics,and the diffusion characteristics demonstrated high diffusivity and high mobility,indicating that the diffusion and reactivity in high-temperature environments plays a key role for the combustion efficiency and the continuation of the chain reaction.It is further revealed that high temperature can effectively promote the generation and consumption of free radicals,thus optimising the combustion efficiency and reducing the generation

关 键 词：褐煤燃烧 大分子结构模型 REAXFF MD 模拟 高温燃烧 自由基动力学 

分 类 号：TQ534[化学工程—煤化学工程]