芦竹燃烧动力学不同反应机理的研究

Combustion kinetics of donax linn

利用热重分析仪进行了芦竹的燃烧试验,采用Coats-Redfern法分析热重曲线,研究不同升温速率(10,20,30℃/min)对燃烧过程的影响。结果表明,芦竹燃烧过程可分为3个阶段,即水分析出、挥发分析出与燃烧及焦炭表面燃烧三个阶段。主要反应集中在第二和第三反应阶段。随着升温速率的增大,最大失重速率增大,三个阶段向高温方向偏移。挥发分析出与燃烧及焦炭表面燃烧阶段的反应机理均满足随机成核A3模型,挥发分析出及燃烧阶段的活化能平均值为21.49 k J/mol,频率因子变化为1.31×10~3~1.83×10~3min^(-1);焦炭表面燃烧阶段的活化能平均值为47.15 k J/mol,频率因子变化为325×10~3~74.9×10~3min^(-1)。

The combustion reactions of donax linn were carried out using the thermogravimetric apparatus,The TG and DTG curves with heating rates of 10,20,30 ℃ / min were used to analysis the combustion characteristic by Coats-Redfern method. The results show that the combustion process of donax linn could be separated into three stages： dehumidification,devolatilization,combustion of volatile and char. The main reactions occur during the second and the third stage. As the heating rate increased,the maximum rate of weight loss was also increased. The TG curve and the peaks in DTG curve shift to higher temperatures due to the heating rate increased. The devolatilization stage and the combustion of volatile and char stage can be described commendably by the model of A3. The activation energies are 21. 49 k J / mol and47. 15 k J / mol,and the pre-exponential factors vary from 1. 31 × 103~ 1. 83 × 103min- 1in the devolatilization stage and vary from 325 × 103~ 74. 9 × 103min- 1in the combustion of volatile and char stage.