Pyrolysis of liulin coal simulated by GPU-based ReaxFF MD with cheminformatics analysis
Pyrolysis of liulin coal simulated by GPU-based ReaxFF MD with cheminformatics analysis
复制标题
基于 GPU 的 ReaxFF MD 模拟柳林煤热解并进行化学信息学分析
DOI：
10.1021/ef402140n
复制
发表时间：
2014
期刊：
影响因子：
5.3
通讯作者：
Song Wenli
中科院分区：
文献类型：
--
作者：
Zheng Mo;Li Xiaoxia;Liu Jian;Wang Ze;Gong Xiaomin;Guo Li;Song Wenli
在这项研究中，使用了第一个性能显著提高、超过CPU实现的ReaxFFMD程序，研究了中国山西烟煤柳林煤热解的初始化学机理和产物分布。由28个 351个原子组成的柳林煤分子模型是用ReaxFFMD进行模拟的最大煤模型，它是基于实验和经典煤模型相结合而构建的。在1000-2600K温度范围内进行了250ps的ReaxFFMD模拟，考察了温度对柳林煤模型热解产物分布和初始化学反应的影响。C14-C40化合物和气体的生成速率在150-250ps范围内趋于平衡，表明模拟应允许大部分热解反应完成，模拟的产物分布对于理解柳林煤热解的化学反应是合理的。模拟中观察到的产物(气体、焦油和焦炭)随时间和温度的演化趋势与文献报道的实验趋势基本一致。特别是，三种具有代表性的产物(萘、甲基萘和二甲基萘)随温度的演化趋势与Py-GC/MS实验非常一致。为了考察ReaxFFMD模拟中化学反应网络的复杂性，新开发的VARMD(可视化和反应分子动力学分析)生成了裂解模拟的详细化学反应。HO·和H3C·自由基的产生和消耗随时间和温度的变化是合理的，与H2O和CH4的演化过程以及得到的详细化学反应是一致的。观察到六元环结构的数量随着时间和温度的增加而减少，这是因为它们转化为五元环或7-9元环或甚至更大的环结构，这些结构将进一步开放并分解成小碎片。这项工作展示了一种新的方法来研究煤的热解机理，将启用GPU的高性能计算与ReaxFF MD的化学信息学分析相结合。
In this study, the first GPU-enabled ReaxFF MD program with significantly improved performance, surpassing CPU implementations, was employed to explore the initial chemical mechanisms and product distributions in pyrolysis of Liulin coal, a bituminous coal from Shanxi, PRC. The largest coal model ever used in simulation via ReaxFF MD, the Liulin coal molecular model consisting of 28 351 atoms was constructed based on a combination of experiments and classical coal models. The ReaxFF MD simulations at temperatures of 1000–2600 K were performed for 250 ps to investigate the temperature effects on the product profile and the initial chemical reactions of the Liulin coal model pyrolysis. The generation rates of C14–C40compounds and gas tend to equilibrate within 150–250 ps, indicating that the simulation should allow most of the thermal decomposition reactions complete and the simulated product profiles are reasonable for understanding the chemical reactions of the Liulin coal pyrolysis. The product (gas, tar, and char) evolution tendencies with time and temperature observed in the simulations are fairly in agreement with the experimental tendency reported in the literature. In particular, the evolution trends of three representative products (naphthalene, methyl-naphthalene and dimethyl-naphthalene) with temperature are very consistent with Py-GC/MS experiments. The detailed chemical reactions of the pyrolysis simulation have been generated using VARMD (Visualization and Analysis of Reactive Molecular Dynamics), which was newly created to examine the complexity of the chemical reaction network in ReaxFF MD simulation. The generation and consumption of HO·and H3C·radicals with time and temperature are reasonable and consistent both with the evolution of H2O and CH4, and with the detailed chemical reactions obtained as well. The amount of six-membered ring structures was observed to decrease with time and temperature, because of their conversion into 5-membered rings or 7–9-membered rings or even-larger-membered ring structures that will further open and decompose into small fragments. This work demonstrates a new methodology for investigating coal pyrolysis mechanism by combining GPU-enabled high-performance computing with cheminformatics analysis in ReaxFF MD.