甲烷气氛下褐煤热解动力学研究

Thermal Pyrolysis Kinetics of Lignitic Coal in Methane Atmosphere

摘要: 以龙口褐煤为原料，在甲烷气氛下分别进行25℃，40℃，55℃，70℃•min–1四个加热速率下的热重分析(TGA)，发现在热解反应过程中甲烷和煤之间具有协同效应。根据热重数据关联了系列不同挥发度下煤的活化能和指前因子等动力学参数。活化能和指前因子随挥发度的变化而变化，指前因子的对数与活化能之间有很好的直线关系，显示出良好的补偿效应，说明龙口褐煤热解反应由许多不同动力学参数的平行反应组成。用活化能分布模型计算了活化能和指前因子的分布函数，该模型能较好的表达褐煤在甲烷气氛下的热解特性。

Abstract: Thermogravimetric analysis (TGA) was carried out for Longkou lignitic coal with four different heating rate of 25˚C, 40˚C, 55˚C and 70˚C•min–1. The experimental results indicated a synergistic effect during methane and coal. The kinetic parameters, activation energies (E) and pre-exponential factors , of thermal pyrolysis for coal at dif- ferent conversion levels were correlated from the thermogavimetric data. The conversion dependent E and k0 values were obtained. The compensation effect is clearly observed from the straight line of the plot of versus E. It indicated that many parallel reaction with different rate parameters occur simultaneously during the pyrolysis of coal. The distribution functions, and , were then established satisfactorily by the distributed activation energy model (DAEM).