煤颗粒燃烧过程氧化机理及有机氮转化的分子模拟：以宁东红石湾煤为例

doi:10.11949/0438-1157.20190657

化工学报 ›› 2020, Vol. 71 ›› Issue (2): 799-810.DOI: 10.11949/0438-1157.20190657

煤颗粒燃烧过程氧化机理及有机氮转化的分子模拟：以宁东红石湾煤为例

杨慧芳(),关海莲,李平(),夏英,王凤,徐文静,白红存,郭庆杰

省部共建煤炭高效利用与绿色化工国家重点实验室，化学国家级实验教学示范中心，宁夏大学化学化工学院，宁夏银川 750021

收稿日期:2019-06-12 修回日期:2019-09-09 出版日期:2020-02-05 发布日期:2020-02-05
通讯作者: 李平
作者简介:杨慧芳（1993—），女，硕士研究生，Yhf_NXU@163.com
基金资助:
宁夏自然科学基金项目(2018AAC03013);宁夏大学区级大学生创新实验(Q2018107490096);宁夏回族自治区科技重大专项(2018BCE01002);宁夏回族自治区国内一流学科建设项目(NXYLXK2017A04)

Molecular modeling of oxidation mechanism and organic nitrogen conversion in coal particle combustion: a case study on HSW coal of Ningdong

Huifang YANG(),Hailian GUAN,Ping LI(),Ying XIA,Feng WANG,Wenjing XU,Hongcun BAI,Qingjie GUO

State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering, National Demonstration Center for Experimental Chemistry Education, College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, Ningxia, China

Received:2019-06-12 Revised:2019-09-09 Online:2020-02-05 Published:2020-02-05
Contact: Ping LI

摘要/Abstract

摘要：

煤燃烧是煤炭资源有效利用的重要方式之一。从原子分子水平上识别煤燃烧的机理，系统把握反应条件的影响，揭示含氮污染物迁移转化的路径对于煤炭高效清洁利用具有重要意义。以前期构建的宁东红石湾煤分子结构模型为基础，采用反应分子动力学模拟方法对煤大分子结构聚集态模型进行燃烧反应模拟，考察化学当量比和反应温度对燃烧过程中结构演变、燃烧反应物和产物的影响，探究有机氮转化路径。研究发现，随着反应不断进行，煤结构的断裂变化非常明显。不同化学当量比和不同温度下煤燃烧的结果表明，化学当量比越大、燃烧温度越高时，O₂分子消耗速度越快，CO₂的生成量也越多。对燃煤过程中含氮气体分子数量的分析表明，HCN是重要的含氮中间产物，NO、NO₂是主要含氮气体产物。本研究还建立了煤燃烧过程中有机氮的转化路径，获得了HCN、NO和NO₂的演变过程。

关键词: 模型, ReaxFF MD, NO_x, 氮转化, 煤燃烧

Abstract:

Coal combustion is one of the important ways for effective utilization of coal. Identifying the mechanism of coal combustion from the atomic and molecular level, systematically grasping the influence of reaction conditions, revealing the path of migration and transformation of nitrogenous pollutants is of great significance for the efficient and clean utilization of coal. Based on the molecular structure model of Ningdong Hongshiwan coal constructed in the previous period, the combustion reaction simulation of coal macromolecular structure aggregation model was carried out by reactive molecular dynamics simulation method. The effects of chemical equivalent and reaction temperature were investigated to explore the coal structural evolution, combustion reactants and products in the combustion process. The organic nitrogen conversion pathway was also revealed. It was found that the fracture change of the coal structure was obvious with the continuous reaction. The results of coal combustion at different stoichiometric ratio and temperature indicated that the larger the stoichiometric ratio and also the higher the combustion temperature, the faster the O₂ molecule consumption rate and the more CO₂were produced. From the analysis of nitrogen-containing molecules in the coal combustion process, it was found that HCN was an important nitrogen-containing intermediate, and NO and NO₂ were the main nitrogen-containing products. Besides, the transformation pathway of organic nitrogen was obtained in coal combustion process, and the evolution of HCN, NO and NO₂ were established.

Key words: model, ReaxFF MD, NO_x, nitrogen conversion, coal combustion

中图分类号:

TQ 530

杨慧芳, 关海莲, 李平, 夏英, 王凤, 徐文静, 白红存, 郭庆杰. 煤颗粒燃烧过程氧化机理及有机氮转化的分子模拟：以宁东红石湾煤为例[J]. 化工学报, 2020, 71(2): 799-810.

Huifang YANG, Hailian GUAN, Ping LI, Ying XIA, Feng WANG, Wenjing XU, Hongcun BAI, Qingjie GUO. Molecular modeling of oxidation mechanism and organic nitrogen conversion in coal particle combustion: a case study on HSW coal of Ningdong[J]. CIESC Journal, 2020, 71(2): 799-810.

图/表 7

图1 不同化学当量比下煤燃烧的可视化过程棕色—C；白色—H；红色—O；蓝色—N

Fig.1 Visualization process of coal combustion under different stoichiometric ratios

图2 不同化学当量比下O2（a）、CO2（b）、CO（c）以及H2O（d）分子数量随时间变化

Fig.2 Time evolution of O2 (a), CO2 (b), CO (c) and H2O (d) with different stoichiometric ratios

图3 不同化学当量比下HCN(a)、NO（b）、NO2（c）以及NOx（d）随时间的变化

Fig.3 Time evolution of HCN (a), NO (b), NO2 (c) and NOx(d) with different stoichiometric ratio

图4 不同温度下煤燃烧的可视化过程棕色—C；白色—H；红色—O；蓝色—N

Fig.4 Visualization process of coal combustion at different temperatures

图5 不同温度下O2（a）、CO2（b）、CO（c）以及H2O（d）随时间变化

Fig.5 Time evolution of O2 (a), CO2 (b), CO (c) and H2O (d) at different temperature

图6 不同温度下HCN（a）、NO（b）、NO2（c）以及NOx（d）随时间的变化

Fig.6 Time evolution of HCN (a), NO (b), NO2 (c) and NOx(d) at different temperature

图7 煤燃烧过程中氮的转化路径

Fig.7 Transformation path way of nitrogen during coal combustion

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煤颗粒燃烧过程氧化机理及有机氮转化的分子模拟：以宁东红石湾煤为例

Molecular modeling of oxidation mechanism and organic nitrogen conversion in coal particle combustion: a case study on HSW coal of Ningdong

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