以软沥青为原料制备有序性中间相焦的研究

【作者】 张海琦；

【导师】 金鸣林；

【作者基本信息】 上海师范大学 ， 工业催化， 2007， 硕士

【摘要】 研究中间相焦的有序性是制备高质量新型炭材料的关键。本课题以煤焦油软沥青SOP为原料,采用带程序升温的多管井式坩埚炉进行热转化反应,研究炭质中间相液相形成机理以及制备有序中间相焦的影响因素。采用高温显微镜连续观察原料在热转化过程中的中间相形成过程;并通过特殊设计的变径管式反应器探索中间相在气流引导下的有序化生成机理,以及原料成分和结构对形成有序性中间相焦的影响。研究结果表明:煤沥青热聚合形成中间相的过程经历三个阶段,即中间相微晶出现初期、中间相微晶堆积形成中间相小球及中间相小球生长期、中间相小球融并形成中间相焦期。随着反应温度的升高,小球的生长速度加快,小球融并将会时间提前进行,最终形成长程无序的细粒镶嵌结构;随着反应温度的下降和时间的延长,中间相有序融并生长更加完善,最终形成长程有序纤维结构。故从促进中间相有序生长的角度,选择相对较低的反应温度,较长的反应时间来制备具有可塑性,即低软化点的中间相预聚体。从热力学角度分析可以发现,热聚合条件下中间相的形成是一个自发过程,而中间相的有序生长是一个非自发过程,需要借助外力的引导作用实现其有序生长。为此,试验设计了一种变径管式单向流反应器,通过热聚合过程中产生的气体的单向流动实现气流对中间相生长的有序的引导作用。变径管式单向流反应器制造气流的原理为:通过变径管底部物料的热裂解产生向上流动的裂解气流,利用中段细径管让气流加速,实现引导细径管中的中间相焦有序生长的作用。此外,试验研究了不同热聚合工艺条件下样品的组成、性质与组织结构变化。通过上述试验研究,为煤沥青资源的深度开发利用、制备高质量针状焦的产业化提供了科学与技术基础。更多还原

【Abstract】 Study on the orderly growth of mesophase coke is the key techniques to develop the needle coke、carbon fibre as well as new carbon materials. Thermal conversion of SOP coal tar pitch to mesophase and ordered mesophase pitch coke was carried out in a multi-tube, well-crucible with programmable temperature control. The courses of thermal polymerization of material to mesophase were continuous observed by high temperature microscope. The mechanism of mesophase liquid crystal to form fiber was studied.The preparation of mesophase concludes the nuclear appearance of mesophase micro-crystal,the growth of mesophase micro-crystal and spheres, as well as the coalescence of mesophase spheres. Along with the increasing of the reaction temperature, the growth rate of mesophase spheres rises up, and the coalescence of mesophase spheres will be ahead of schedule.. In addition, the formation of mesophase coke will be more perfect with the longer reaction time. So, the fitting reaction temperature and time is very important.On the thermodynamics side, the thermal polymerization of coal tar pitch forming mesophase pitch is a spontaneous process, though the ordered growth of mesophase coke is not a spontaneous process, which need function of outside force.The effect of the single flow of pyrolysis gaseous is significant to the ordered growth of mesophase coke. The thermal polymerization of coal tar pitch was carried out in a novel tubular reactor reducing in the central section which contained pneumatic guide structure. The ordered growth of mesophase was guided by the oriented flowing gas stream of reaction tubular to form ordered mesophase coke. Moreover, study on the change with the structure, properties of samples with different treatment conditions is carried out.The fore-mentioned study provides a scientific and technique basis for the further application of coal tar pitch, as well as preparation industrialization of high quality needle coke.更多还原