煤氧化-热解进程的增失重阶段与动力学三因子分析

Analysis on the weight increment and weight loss stage and the kinetic triplet during the oxidation- pyrolysis process of coal

为分析煤氧化-热解进程的增失重阶段与动力学三因子,根据同一氧体积分数、5种不同升温速率下煤氧化-热解的TG-DTG曲线,探讨了煤氧化-热解进程经历的增失重阶段,基于Popescu法计算了不同阶段的动力学三因子。结果表明实验煤样的氧化-热解进程可分为失水失重、氧化增重、燃烧失重和燃尽恒重4个阶段。失水失重、氧化增重和燃烧失重阶段的反应机理分别为Mample单行法则、三维扩散模型和相边界反应的收缩球体模型;活化能分别为54.128 k J·mol-1、152.252 k J·mol-1和134.458 k J·mol-1;指前因子的自然对数分别为16.832 s-1、32.597s-1和18.365 s-1。

In order to analysis the weight increment and weight loss stage and the kinetic triplet during the oxidation-pyrolysis process of coal, based on the TG-DTG curves of coal oxidation-pyrolysis under the same oxygen volume fraction and five different heating rates, the weight increment and weight loss stage in the oxidation-pyrolysis process of coal was studied, and the kinetic triplet were calculated by the Popescu method. The result showed that the oxidation-pyrolysis process of coal sample can be separated into four stages which are respectively the weight loss stage by water loss, the weight increment stage by oxidation, the weight loss stage by combustion and the con- stant weight stage after burnout. The reaction mechanisms of the first three stages are respectively the single line law of Mample, the three dimensional diffusion model and the shrink sphere model of phase boundary reaction. The activation energies are respectively 54. 128 kJ ·mol^-1, 152. 252 kJ ·mol^-1 and 134. 458 kJ ·mol^-1, and the natural logarithm of the pre-exponential factors are respectively 16. 832 s^-1, 32. 597 s^-1 and 18. 365 s^-1.