基于热重的煤热解反应动力学试验研究

Experimental study on coal pyrolysis kinetics based on thermogravimetry analysis

采用热重分析法对4种不同粒径范围内的5种不同煤样进行热解特性试验研究,以考察煤化程度和粒径对煤热解过程的影响规律,同时对其热解动力学进行了特性分析。试验结果表明,煤的热解反应活性随着煤化程度的增加而逐渐降低;煤的传质传热受到粒径影响,煤的热解总失重率随着粒径的增大而减少,但当粒径小于一定数值时,蒙东褐煤、河曲2#煤和孙家沟煤的热解总失重率反而随着粒径的减少略有增加。在热重试验的基础上建立热解反应动力学模型并求解模型参数,把握热解特征和规律,以期在一定程度上对煤炭地下气化提供相应的理论指导。

Experimental study on pyrolysis characteristics of five different coal samples in four different particle size ranges was conducted by thermogravimetric analysis,the influencing rules of coalification degree and particle size on the coal pyrolysis process were investigated,and the pyrolysis kinetics was analyzed.The results showed that the pyrolysis reaction activity of coal decreased with the increase of coalification degree;the mass and heat transfer of coal was affected by the particle size,and the total weight loss rate of coal pyrolysis decreased with the increase of particle size.However,when the particle size was less than a certain value,the total weight loss rate of coal pyrolysis of Mengdong lignite,Hequ 2#coal and Sunjiagou coal slightly increased as the particle size decreased.On the basis of thermogravimetric test,the pyrolysis kinetics model was established and the model parameters were solved to grasp the characteristics and laws of pyrolysis,which provided corresponding theoretical guidance for underground coal gasification to a certain extent.