煤田地质与勘探2024，Vol.52Issue(7)：132-143,12.DOI:10.12363/issn.1001-1986.24.01.0024
陕北富油煤分子模型构建及其热解提油分子动力学特性
Molecular modeling of tar-rich coals from northern Shaanxi and their molecular dynamic characteristics in the process of pyrolysis for tar extraction
摘要
Abstract
[Objective]The pyrolysis process and mechanism of tar-rich coals remain unclear due to their complex struc-tures.Therefore,it is necessary to investigate the structure-activity relationship between their structure and the distribu-tions of their pyrolytic products and determine the mechanism behind their pyrolysis for tar extraction.[Methods]Fo-cusing on typical tar-rich coals from northern Shaanxi Province,this study calculated and constructed the molecular model of the coals using characterization methods such as carbon-13 nuclear magnetic resonance(13C NMR),Fourier transform infrared spectroscopy(FTIR),and X-ray photoelectron spectroscopy(XPS),determining the molecular for-mula at C444H380O74N8S.Based on the molecular model,this study examined the pyrolytic product distributions,pyrolys-is characteristics,and tar production mechanism of the tar-rich coals using the reactive force field molecular dynamics(ReaxFF MD).[Results and Conclusions]The results reveal that the tar-rich coals from northern Shaanxi Province ex-hibit substantial hydrogen-rich structures,such as aliphatic side chains and bridge bonds,tending to decompose into volatile constituents like tar and gas when heated.The product distributions during the pyrolysis of tar-rich coals are sig-nificantly influenced by the temperature and heating rate.At a simulated pyrolysis temperature of 1 500 K,the tar-rich coals underwent partial reactions,yielding volatile constituents with a mass fraction of 7.8%.As the simulated pyrolysis temperature rose to 2 000 to 3 000 K,molecular and radical fragments moved more intensely,accompanied by more pro-nounced secondary reactions.With an increase in the heating rate,gas products decreased,whereas tar products in-creased first and then decreased.At heating rates between 100 and 200 K/ps,the tar-rich coals were partially pyrolyzed,leading to mass fractions of volatile constituents below 36%.As inferred from the distributions of pyrolytic products,the mechanism behind the pyrolysis of tar-rich coals from northern Shaanxi Province is that the hydrogen-rich structures in tar-rich coal macromolecules break under heating,forming radical fragments,which are further pyrolyzed to produce light tar,heavy tar,and gas.关键词
富油煤/煤热解/分子模拟/热解温度/升温速率/模型构建/富氢结构Key words
tar-rich coal/coal pyrolysis/molecular simulation/pyrolysis temperature/heating rate/model construction/hydrogen-rich structure分类
化学化工引用本文复制引用
郭伟,杨盼曦,俞尊义,杨甫,王晶,马丽,李红强,杨伯伦,吴志强..陕北富油煤分子模型构建及其热解提油分子动力学特性[J].煤田地质与勘探,2024,52(7):132-143,12.基金项目
自然资源部煤炭资源勘查与综合利用重点实验室开放基金项目(SMDZ-2023-Z020) （SMDZ-2023-Z020）
陕西省创新能力支持计划项目(2023-KJXX-004,2022KXJ-126) （2023-KJXX-004,2022KXJ-126）
