CIESC Journal ›› 2020, Vol. 71 ›› Issue (2): 811-820.DOI: 10.11949/0438-1157.20191156

• Energy and environmental engineering • Previous Articles     Next Articles

Pyrolysis characteristics and kinetics analysis of Qinghua coal, Ningxia based on chemical bonding characteristics of macerals

Ning MAO1,Qiang WANG1,Yan YANG1,Dunxin XU2,Wei FENG1,Jinpeng ZHANG1,Hongcun BAI1(),Qingjie GUO1   

  1. 1.State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering, College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, Ningxia, China
    2.Ningxia Kingho Coal Chemical Group Co. , Ltd. , Wuzhong 751100, Ningxia, China
  • Received:2019-10-10 Revised:2019-11-08 Online:2020-02-05 Published:2020-02-05
  • Contact: Hongcun BAI

基于显微组分化学键特征的宁夏庆华煤热解特性及动力学分析

毛宁1,王强1,杨妍1,徐敦信2,冯炜1,张金鹏1,白红存1(),郭庆杰1   

  1. 1.宁夏大学省部共建煤炭高效利用与绿色化工国家重点实验室,化学化工学院,宁夏 银川 750021
    2.宁夏庆华煤化集团有限公司,宁夏 吴忠 751100
  • 通讯作者: 白红存
  • 基金资助:
    宁夏高校项目(NGY2016064);宁夏重点研发计划重大科技项目(2018BCE01002);宁夏高等学校一流学科建设项目(NXYLXK2017A04)

Abstract:

X-Ray photoelectron spectroscopy and Fourier transform infrared spectroscopy were used to characterize the functional group types, surface structure element valence distribution and chemical bond occurrence characteristics of Ningxia Ningdong Qinghua coal. Then the mass loss behavior of vitrinite and inertinite of Qinghua coal at different pyrolysis temperatures and the changes of key gas components were investigated by means of the thermogravimetry coupled with mass spectrometry (TG-MS). Furthermore, the differences of pyrolysis behavior between vitrinite and inertinite were discussed from the point of view of chemical bonding breaking and pyrolysis kinetics based on Coats-Redfern model. The results show that the pyrolysis weightlessness peaks of Qinghua coal macerals at different temperatures are in good agreement with the information of corresponding chemical bond breaking. The TG curves of different macerals of Qinghua coal are similar, but the mass loss rate of vitrinite is always higher than that of inertinite at the same pyrolysis temperature. In the fast pyrolysis stage, vitrinite exhibits greater mass loss rate and also maximum mass loss rate than inertinite. The main reason is that the relative content of aliphatic functional groups in vitrinite is higher, and more Cal—Cal bonds would break down during the fast pyrolysis stage. The order of activation energy and frequency factor of three main pyrolysis stages of Qinghua coal macerals at different pyrolysis temperatures is: fast pyrolysis stage > fast polycondensation stage > slow pyrolysis stage. In the fast pyrolysis stage, the average activation energies of vitrinite and inertinite are both about 75 kJ/mol, but the frequency factor of vitrinite is higher.

Key words: fuel, pyrolysis, kinetic theory, coal macerals, chemical bond characteristics

摘要:

通过X射线光电子能谱和傅里叶红外光谱表征宁夏宁东庆华煤不同显微组分的官能团种类、表面结构元素价态分布及化学键赋存特征。采用热重-质谱联用考察庆华煤镜质组和惰质组在不同热解温度下的失重行为和关键气体组分变化。进一步基于Coats-Redfern模型从化学键断裂特征和反应动力学角度探讨煤镜质组和惰质组的热解行为差异。结果表明,庆华煤显微组分的热解失重峰与相应化学键断裂信息能够很好地吻合。不同显微组分的热重曲线变化趋同,但相同热解温度下镜质组的失重率始终高于惰质组。快速热解阶段镜质组较惰质组表现出更大的失重率和最大失重速率。其主要原因在于镜质组的脂肪族官能团相对含量更高,快速热解阶段会发生更多的Cal—Cal断裂。不同热解温度下庆华煤显微组分三个主要热解阶段的活化能和频率因子大小次序为:快速热解阶段>快速缩合阶段>缓慢热解阶段。在快速热解阶段,镜质组和惰质组的平均活化能均约为75 kJ/mol,但镜质组的频率因子更高。

关键词: 燃料, 热解, 动力学理论, 煤样显微组分, 化学键特征

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