竹材非等温热解动力学

Non-isothermal kinetics of pyrolysis of bamboo

利用热重分析技术对竹材在高纯N2条件下,从室温至1273K进行了非等温热解分析,研究了升温速率(5、10、20和40K/min)对热解过程的影响,探讨了其热解机理。研究表明,竹材非等温热解过程主要分为失水干燥、快速热解和缓慢分解三个阶段组成,其中第二阶段是整个过程的主要阶段,析出大量挥发分造成明显失重。升温速率对热解过程有显著影响,随着升温速率的增加,最大热解速度增大,对应的峰值温度升高,热滞后现象加重,热解各阶段向高温侧移动。热解机理满足一维扩散Parabolic法则,反应机理函数为g(α)=α2。不同升温速率下活化能为75.32-82.99kJ.mol-1,指前因子为1.17×105-1.12×106min-1。

The non - isothermal thermal degradation of bamboo was carried out in high pure nitrogen atmosphere from room temperature to 1273K, and the influence of heating rates of 5, 10,20 and 40K/min on the pyrolysis was investigated by thermogravimetric method. The mechanism of the thermal degradation was discussed. The results indicate that the non - isothermal thermal degradation process of bamboo has three distinct stages ： dehydration, rapid pyrolysis and slow weight - loss. The second stage plays an important role in the whole process in that a huge amount of released volatile caused the distinct weight loss of bamboo. The heating rates show remarkable influence on the thermal degradation process. With the increasing of heating, rate of the maximum decomposition rate and its corresponding temperatures of bamboo increase. The TG curve and DTG peak shifted to higher temperature due to the increase in thermal Lag. The thermal degradation mechanism of bamboo is suitable for I D diffuse Parabolic principle and the reaction mechanism function is g（a） = a2. The activation energies range from 75.32 to 82.99 kJ ·mol ^-1and the pre -exponential factors vary from 1.17 × 10^5 to 1.1 ×10^6min^-1 at different heating rates.