摘要
煤热解与甲烷二氧化碳重整耦合(CP-CRM)过程是提高焦油产率的重要方法之一。煤的显微组分组成是影响煤热解反应过程的因素之一,N2气氛下的显微组分热解过程已有较为深入的研究,但显微组分在CP-CRM过程中的热解行为规律尚待研究。通过固定床实验探讨不同反应温度和气氛对显微组分热解产物分布规律的影响,对比研究了甲烷二氧化碳重整(CRM)与N2气氛下大柳塔原煤及显微组分热解特性的差异。通过模拟蒸馏、核磁共振和GC-MS等表征方法对焦油进行分析,认识显微组分结构对热解焦油组成的影响。结果表明,在N2气氛下,镜质组和惰质组展现出不同的反应特性,镜质组热解焦油产率明显高于惰质组,主要归结于显微组分结构的差异导致的反应性不同。CRM气氛能显著提高热解焦油的产率,尤其对惰质组的作用效果最明显,使惰质组的焦油产率相比N2气氛提高16%,主要归结于CRM过程产生的自由基参与煤热解反应。焦油组成分析表明,在N2气氛下得到的热解焦油中,镜质组具有较高比例的脂肪类物质,惰质组具有较高比例的芳香类物质; CRM气氛下焦油中单环芳香烃的比例提高,轻质组分中蒽油的相对含量提高最为显著,同时CRM气氛下惰质组产生的焦油中三环、四环芳香烃的比例明显下降。
The integrated process of coal pyrolysis with CO2 reforming of methane(CP-CRM) is one of the most important routes to improve tar yield.The composition of coal macerals is one of the factors affecting the pyrolysis reaction process.However,there is a lack of research on the pyrolysis behavior of macerals in the CP-CRM process.This work studied the differences of pyrolysis characteristics of Daliuta raw coal and its macerals under N_2 and CRM atmosphere.The effects of different reaction temperatures and atmospheres on the distribution of pyrolysis products of macerals were investigated on a fixed bed pyrolysis apparatus.The obtained pyrolysis tar was analyzed by simulated distillation,NMR and GC-MS to understand the effect of the structure of macerals on the composition of tar. The results show that the vitrinite and inertinite exhibit different reaction characteristics under N_2 atmosphere.The tar yield of vitrinite is significantly higher than that of inertinite,which is mainly attributed to the difference in the reactivity caused by the difference in the structure of macerals.The CRM atmosphere could obviously increase tar yield.In comparison,the enhance-ment effect is more pronounced when the inertinite is used,and the tar yield of inertinite is increased by 16% compared with that under N_2 atmosphere,which is mainly ascribed to the participation of free radicals from CRM.The analysis of tar composition shows that the vitrinite pyrolysis tar contains higher aliphatics,while inertinite pyrolysis tar includes more aromatics under N_2 atmosphere.Under the CRM atmosphere,the content of light aromatic hydrocarbons is greatly increased,especially,the content of anthracene oil is most remarkably enhanced,and the content of tricyclic and tetracyclic aromatic hydrocarbons in the inertinite pyrolysis tar is obviously decreased.
引文
[1] WANG Junhong,DU Juan,CHANG Liping,et al.Study on the structure and pyrolysis characteristics of Chinese western coals[J]. Fuel Processing Technology,2010,91(4):430-433.
[2] ZHAO Yunpeng,HU Haoquan,JIN Lijun,et al.Pyrolysis behavior of vitrinite and inertinite from Chinese Pingshuo coal by TG-MS and in a fixed bed reactor[J]. Fuel Processing Technology,2011,92(4):780-786.
[3]孙庆雷,李文,陈皓侃,等.神木煤显微组分热解和加氢热解的焦油组成[J].燃料化学学报,2005,33(4):412-415.SUN Qinglei,LI Wen,CHEN Haokan,et al. Composition of coal tar from pyrolysis and hydropyrolysis of Shenmu coal macerals[J].Journal of Fuel Chemistry and Technology,2005,33(4):412-415.
[4]赵伟,张晓欠,周安宁,等.神府煤煤岩显微组分的浮选分离及富集物的低温热解产物特性研究[J].燃料化学学报,2014,42(5):527-533.ZHAO Wei,ZHANG Xiaoqian,ZHOU Anning,et al. Flotation separation of Shenfu coal macerals and low temperature pyrolysis characteristics of different maceral concentrate[J].Journal of Fuel Chemistry and Technology,2014,42(5):527-533.
[5]孙庆雷,李文,李保庆.神木煤显微组分热解特性研究[J].中国矿业大学学报,2001,30(3):272-276.SUN Qinglei, LI Wen, LI Baoqing. Study on pyrolysis of maceal conentrate from Shenmu coal[J].Journal of China University of Mining&Technology,2001,30(3):272-276.
[6]孙庆雷,李文,李东涛,等.神木煤有机显微组分的结构特征与热转化性质的关系[J].燃料化学学报,2003,31(2):97-102.SUN Qinglei,LI Wen,LI Dongtao,et al. Relationship between structure characteristics and thermal conversion property of Shenmu maceral concentrates[J]. Journal of Fuel Chemistry and Technology,2003,31(2):97-102.
[7]王传格,张妮,陈燕.煤显微组分结构特征及其与热解行为的关系[J].煤炭转化,2011,34(3):11-16.WANG Chuange,ZHANG Ni,CHEN Yan. Relationship between structural characterization of macerals and their thermal behavior[J].Coal Conversion,2011,34(3):11-16.
[8]高松平,王建飞,赵建涛,等.H2气氛下褐煤快速热解过程中CH4逸出规律的分析[J].燃料化学学报,2015,43(5):537-545.GAO Songping,WANG Jianfei,ZHAO Jiantao,et al.Analysis of CH4evolution in fast pyrolysis of lignite under H2atmosphere[J].Journal of Fuel Chemistry and Technology,2015,43(5):537-545.
[9] LIU Jiahe,HU Haoquan,JIN Lijun,et al. Integrated coal pyrolysis with CO2reforming of methane over Ni/Mg O catalyst for improving tar yield[J]. Fuel Processing Technology,2010,91(4):419-423.
[10] JIN Lijun,ZHOU Xun,HE Xinfu,et al. Integrated coal pyrolysis with methane aromatization over Mo/HZSM-5 for improving tar yield[J].Fuel,2013,114:187-190.
[11] HE Xinfu,JIN Lijun,WANG Ding,et al.Integrated process of coal pyrolysis with CO2reforming of methane by dielectric barrier discharge plasma[J].Energy&Fuels,2011,25(9):4036-4042.
[12] DONG Chan,JIN Lijun,LI Yang,et al.Integrated process of coal pyrolysis with steam reforming of methane for improving the tar yield[J].Energy&Fuels,2014,28(12):7377-7384.
[13] WANG Pengfei,JIN Lijun,LIU Jiahe,et al.Analysis of coal tar derived from pyrolysis at different atmospheres[J]. Fuel,2013,104:14-21.
[14] MARIA JosèIglesias,MARIA JosèCuesta,ISABEL Suàrez-Ruiz.Structure of tars derived from low-temperature pyrolysis of pure vitrinites:Influence of rank and composition of vitrinites[J]. Journal of Analytical and Applied Pyrolysis,2001,58:255-284.
[15] DIAZ C,C G Blanco.NMR:A powerful tool in the characterization of coal tar pitch[J].Energy&Fuels,2003,17(4):907-913.
[16] TREVOR J Morgan,ANTHE George,DAVID B Davis,et al.Optimization of1H and13C NMR methods for structural characterization of acetone and pyridine soluble/insoluble fractions of a coal tar pitch[J].Energy&Fuels,2008,22(3):1824-1835.