氢等离子体裂解煤制乙炔结焦物形成机理  

Coking Mechanism During the Process of Acetylene Preparation from Coal Pyrolysis in Hydrogen Plasma

作　　者：方世东[1] 李绪奇[2] 赵颖[2] 陈龙威[1] 沈洁[1] 孟月东[1] 

机构地区：[1]中国科学院等离子体物理研究所,合肥230031 [2]合肥工业大学医学工程学院,合肥230009

出　　处：《高电压技术》2013年第7期1590-1595,共6页High Voltage Engineering

基　　金：国家自然科学基金(11205201)~~

摘　　要：为研究氢等离子体裂解煤制乙炔过程中的结焦物形成机理,用扫描电子显微镜(SEM)和X射线衍射(XRD)对反应器内混合段和反应段结焦物进行了分析。结果表明不同位置的结焦物形貌和石墨化程度不同:混合段结焦物以碳纳米管和碳微球为主,石墨化程度最高;第一反应段结焦物中碳微球颗粒较大,石墨化程度较高;第二反应段结焦物中有炭黑颗粒,石墨化程度较低。结合化学平衡理论分析,推测了结焦物不同的原因是裂解产物经历了不同途径形成结焦:混合段中煤粉颗粒、气态碳、固态碳,在壁面形成结焦;第一反应段中气态碳的气相沉积对壁面结焦影响增加;第二反应段结焦以固相吸附而形成。对不同挥发份的煤进行了实验,发现挥发份高的煤结焦严重。因此为减少或抑制结焦物形成,应选用低挥发份煤。For further understanding the mechanism of coking,we analyzed coke samples at the mixing section,the first reaction section,and the second reaction section of a reactor by scanning electron microscope（SEM） and X-ray diffraction（XRD）.The results show that the micro structural aspects and the degree of graphitization of the cokes at different locations were different.The coke samples at the mixing section were dominated by carbon nanotubes and carbon microbeads,with the highest degree of graphitization among the three sections;at the first reaction section,the particles of carbon microbeads in sample were relatively coarse,and the degree of graphitization was relatively high;and at the second reaction section,the coke samples contained carbon black particles,but the degree of their graphitization was relatively low.In combination with chemical equilibrium theoretical analysis,it was speculated that the cause of different cokes was that the pyrolysis product had undergone different ways of formation of carbon deposits.The coal powder particles,gaseous carbon,solid-state carbon,and ionic carbon at the mixing section were on the wall surface;the effect of vapor deposition of gaseous carbon at the first reaction section on the coke on wall surface increased;the coke at the second reaction section took place in the form of solid-state adsorption.By conducting pyrolysis of coal with two different kinds of volatiles,it was found that the coking of the coal with high volatiles content was severe.In order to reduce or inhibit coke formation,low volatile coal should be adopted.

关 键 词：氢等离子体 裂解 煤 乙炔 结焦物 石墨化 

分 类 号：TQ221.242[化学工程—有机化工]