煤系针状焦煅烧过程中焦炭微晶结构的演变规律  

Evolution of coke microcrystalline structure during calcination process of coal-based needle coke

作　　者：程俊霞[1] 朱亚明[1] 高丽娟[1] 赵雪飞[1] CHENG Jun-xia;ZHU Ya-ming;GAO Li-juan;ZHAO Xue-fei(College of Chemical Engineering,University of Science and Technology Liaoning,Anshan 114051,China)

机构地区：[1]辽宁科技大学化工学院,辽宁鞍山114051

出　　处：《燃料化学学报》2020年第9期1071-1078,I0004,共9页Journal of Fuel Chemistry and Technology

基　　金：国家自然科学基金(U1361126);辽宁省自然科学基金(20180551218);辽宁省教育厅项目(2017LNQN04);辽宁科技大学优秀人才培养项目(2018RC07);辽宁科技大学青年基金(2016QN25,2017QN06);辽宁科技大学开放基金(USTLKFSY201701)资助。

摘　　要：以煤系针状焦的生焦为原料,在2和5℃/min的升温速率下进行煅烧,采用FT-IR、XRD、Raman光谱等分析手段研究煅烧过程中针状焦微晶结构的演变规律。结果表明,随着煅烧温度的升高,针状焦中碳微晶的直径La、炭微晶的高度Lc、晶体中的片层含量N以及每层中平均碳原子数n、趋于规整的石墨微晶含量Ig逐渐升高。但是受挥发分逸出和生焦收缩的影响,Lc出现了明显的“拐点”。新增片层与原有片层间存在的随机“层错”,导致层间距d002的波动。相同温度下升温速率越快,晶格尺寸越小,片层含量N及每层平均碳原子数n越少,Lc出现“拐点”的温度越靠后。理想石墨微晶含量(IG/Iall)随温度的升高逐渐增加;而具有缺陷的石墨微晶间在煅烧过程中不断相互转化,最终发育为理想石墨微晶。碳网平面上C-C键平均键长α则随着煅烧温度的升高明显增加。The evolution of the microstructure of needle coke during calcination process has been determined by FT-IR,XRD,and Raman spectroscopy,in which the needle cokes were obtained by calcination at heating rates of 2 and 5℃/min with the coal-based green needle coke as the raw materials,respectively.The results show that the diameter of carbon microcrystal L a,the height of carbon microcrystal L c,the lamella content in the crystal(N),the average carbon number in each layer(n),and the content of tending regular graphite micro crystals(I g)in the needle coke increase gradually with the rising of the calcination temperature.However,the value of L c appears an"inflection point"due to the escape of volatiles and shrinkage of green needle coke.The layer spacing d 002 fluctuates due to the random"layer fault"between the new layer and the original layer.The higher the heating rate,the smaller the characteristic carbon microcrystal parameters(L a,L c,N,and n)of needle coke,and the latter the temperature of"inflection point"for L c appears.Also,the content of perfect graphite microcrystallite(I G/I all)increases gradually with the increasing of temperature,and the defective graphite microcrystallites transforms to each other continuously during calcination process,finally being developed into the graphite microcrystals.The average bond length α of C-C bond in the carbon planes would become larger with the increase of calcination temperature.

关 键 词：煤系针状焦 XRD RAMAN 微晶结构 C-C键平均键长 

分 类 号：TQ52[化学工程—煤化学工程]