稻壳与聚氯乙烯共热解的特性及动力学

在热重分析仪中进行了稻壳和聚氯乙烯（PVC）的共热解实验，结果显示:在共热解时稻壳开始剧烈热解的温度相比单独热解时大幅度降低，由350℃降至300℃，表明掺入PVC降低了稻壳的热解温度。在升温速率为20℃/min，稻壳和PVC比例为2∶1（质量比）时，混合热解协同效应最明显。3种动力学分析方法均证明共热解现象的存在。利用Coats-Redfern法进行动力学分析，发现共热解活化能普遍较单独热解时低，表明PVC与稻壳共热解有明显的相互作用。利用Ozawa法进行分析，发现转化率为20%~60%阶段下共热解平均活化能值为37.60 kJ/mol，低于稻壳单独热解的平均活化能41.45 kJ/mol。Friedman法分析结果显示对应转化率下共热解活化能均低于稻壳单独热解活化能。稻壳和PVC共热解倾向于反应动力学控制。

CHARACTERISTICS AND KINETICS OF CO-PYROLYSIS OF RICE HUSK AND PVC

Rice husk and polyvinyl chloride (PVC) pyrolysis experiments were carried out in a thermogravimetric analyzer and corresponding kinetic analysis was carried out. It was found that the temperature of the first pyrolysis peak of rice husk in co-pyrolysis was significantly lower than that of mono-pyrolysis of rice husk, from 350℃ to 300℃, indicating that the adding of PVC elevated the pyrolysis of rice husk. When the heating rate was 20℃/min and the ratio of rice husk to PVC was 2∶1, the rate of co-pyrolysis was the highest. Three kinetic analysis methods were more powerful in explaining the existence of the phenomenon of co-pyrolysis. The Coats-Redfern method demonstrated that the co-pyrolysis activation energy was generally lower than that of mono-pyrolysis. The Ozawa method displayed that, in the pyrolysis conversion from 20% to 60%, the average activation energy of the co-pyrolysis was 37.60 kJ/mol, lower than that of mono-pyrolysis of rice husk, 41.45 kJ/mol. In the Friedman method, the activation energy of co-pyrolysis at the corresponding conversion rate was lower than that of mono-pyrolysis of rice husk. The result showed that co-pyrolysis performed as a reaction kinetic control process.