沥青热解模型  

Pyrolysis model of pitch

作　　者：任呈强[1] 李铁虎[1] 宋发举[1] 

机构地区：[1]西北工业大学材料学院

出　　处：《化学工程》2007年第7期27-30,共4页Chemical Engineering(China)

基　　金：国家自然科学基金资助项目(50472081)

摘　　要：沥青是制备炭材料的重要前驱体之一,深入理解其炭化行为有助于控制炭产品性能。采用峰值分离的方法对沥青的DTG曲线进行分解,得到3个部分交叠的温度区间,用三阶段连续伪组分反应动力学模型拟合发现,3个阶段均是一级反应。并对2.5 K/m in至10 K/m in加热速率下的热质量损失曲线进行计算,结果与实验数据吻合良好。对炭化过程中挥发分形成的气泡的生长动力学进行理论计算,结果表明,气泡的直径随温度升高单调增加,沥青的热解质量损失率是气泡生长的控制因素。相同热解温度下,气泡外围的液体径向速度随加热速率的增加而成倍增加,因此加热速率应该遵循'两头快,中间慢'的原则。Pitch is one of the most important precursors of the carbon materials. A deep understanding of the carbonization behaviors is helpful to better controlling the performances of the final products. Three partly overlapping temperature stages from the DTG curve of pitch were obtained by peak separation. Three series reactions of three pseudo-compositions were proposed to model them. The result shows that pyrolysis in each stage is first-order reaction. The calculated TG curves agree well with experimental data when the heating rate are increased from 2.5 K/min to 10 K/min. The dynamic of bubble growth caused by the volatiles during pyrolysis of pitch was theoretically calculated. It indicates that with the increase of heating rate, the diameter of bubble monotonously increases. The mass loss rate of pitch is the controlling factor to the bubble growth. The radical velocity of liquid around the bubble rapidly increases with heating rate at the medium temperature of the pyrolysis. It suggests that the heating schedule should be programmed as low rate in the medium temperature stage but high rate in the other temperature stages.

关 键 词：沥青 热解 动力学 气泡 

分 类 号：TQ520.1[化学工程—煤化学工程]