温度对等离子体热解烃类生成炭黑形貌的影响

The Influence of Temperature on the Morphology of Carbon black Enerated by Thermal Pyrolysis of Hydrocarbon Pyrolysis in Plasma

使用磁旋转电弧等离子体发生器产生均匀的高温热源,通过热解碳氢化合物制备了炭黑颗粒。利用透射电子显微镜(TEM)图像,表征了炭黑聚集体的形貌,计算了聚集体的分形维数、粒度分布和平均粒径,研究了反应温度和原料对炭黑聚集体形貌和微观物理特性的影响。研究结果显示,在1500 K较低温度下所有热解产物均为球形碳颗粒;随着温度的升高,初级粒子粒径减小,分形维数变大,聚集体形态变复杂;甚至在约2500 K高温下在甲烷和乙烯的热解产物中出现石墨烯片层。分析认为,温度和原料影响了初级粒子的成核速率、表面生长和碰撞团聚等过程,从而决定了聚集体的最终形貌。

Carbon black is prepared by hydrocarbons pyrolysis using a magnetically rotating arc at atmospheric pressure.The effect of reaction temperature and hydrocarbons species on the morphology of products are studied.The transmission electron microscopy(TEM)and image postprocessing are applied to characterize the fractal dimension,particle size distribution and average particle size.Results show that all products are spherical carbon particles at lower reaction temperature(1500 K).As the temperature increases,the primary particle size decreases,the frac-tal dimension becomes larger,and the morphology becomes more complex.Additionally,the graphene flakes are obtained by the pyrolysis of meth-ane and ethylene at higher reaction temperature(2500 K).Preliminary analysis indicates that the process of nucleation,surface growth and colli-sions of primary particles are affected by the reaction temperature and hydrocarbons species,which determines morphology of final products.