ReaxFF动力学分析煤热反应机理

为了从微观角度研究煤的热解机理,找出热解过程中反应路径、中间产物等反应信息,用Reax FF动力学的方法分析煤的热反应机理。阐述了模拟过程中煤分子体系的构建、模拟结果的处理方法,介绍了如何通过监测自由基中间体种类,获得反应过程中常见产物的分布和基元反应,进而解释煤热解、氧化和水热处理等反应过程的机理,并对Reax FF动力学在煤热反应体系中复杂化学反应的研究前景进行展望。通过Reax FF方法可模拟煤的热反应过程,可以获得主要产物的生成路径、产物种类、产物的生成顺序等信息,还可以研究煤热解过程中煤分子间或与其他分子间的相互作用,进而分析热解过程中煤的热反应机理。后续可通过时温等效原理建立模拟温度与实际温度的定量关系,解决Reax FF方法模拟温度与实际温度不对应的问题;通过编写相应的后台程序缩短模拟计算结束后数据的处理时间。

Application of ReaxFF molecular dynamics on coal thermal reaction mechanism

In order to investigate the pyrolysis mechanism of coal and find the reaction path and intermediate products from microscopics,the reactive force field (ReaxFF) molecular dynamics was adopted to study the pyrolysis of coal.The establishment of coal molecules,the processing of the results during simulation were introduced.The mechanism of pyrolysis,oxidation and hydrothermal reaction were explained by the distribution of familiar products and elementary reactions which could be got through detecting the free radicals in the pyrolysis.The application of ReaxFF molecular dynamics on the field was forecast.The generation pathways of main products,the kinds of the products and the generation sequence of the products could be gotten by simulating the thermal reaction of coal through ReaxFF.The interactions between coal molecules and other molecules in the pyrolysis also could be gotten.Quantitative relation between simulation temperature and actual temperature could be figured out by time temperature equivalence principle.A lot of time could be saved by corresponding post processor to process the data in the pyrolysis.