摘要
研究塑料废弃物的热解特性有助于实现其清洁高效转化利用.借助热重技术总结对比了高密度聚乙烯、低密度聚乙烯和聚丙烯的不同升温速率(10,20,30,40,50 ℃/min)热解及不同催化剂(HZSM-5、Hβ和HUSY)催化热解的特性及规律.升温速率的增长使反应出现热迟滞现象,催化剂的加入对样品热解速率提高的效果也不尽相同.为了提供更有力的理论支持,运用3种动力学分析方法Coats-Redfern(CR)、Flynn-Wall-Ozawa(FWO)和分布式活化能法(DAEM),对样品在不同条件下的动力学参数进行计算和分析.CR模型验证了各热解反应符合一级化学反应模型并发现催化剂可以大幅降低反应活化能;FWO法和DAEM得到的表观活化能数值接近.DAEM模型显示活化能在转化率α增长的过程中先上升再逐步下降,在α=40％～50％时活化能最高,且包含动力学补偿效应.
Abstract
The study on pyrolysis characteristics of plastic waste is in favor of achieving its clean and efficient conversion and utilization.The catalytic pyrolysis characteristics of high-density polyethylene(HDPE),low-density polyethylene(LDPE),and polypropylene(PP),with three different catalysts of HZSM-5,Hβ and HUSY,were investigated by the thermogravimetric experiments at different heating rates of 10,20,30,40,50 ℃/min.The increase of heating rate caused thermal hysteresis,and the different types of catalysts had different effects on the improvement of pyrolysis rates of the HDPE,LDPE,and PP.In order to provide theoretical support,three kinetic modeling analysis methods,including Coats-Redfern(CR),Flynn-Wall-Ozawa(FWO),and distributed activation energy model(DAEM),were used to calculate the kinetic parameters of HDPE,LDPE,and PP pyrolysis under different conditions.CR method verified that each pyrolysis reaction was following the first-order reaction model and found that the catalysts could significantly reduce the activation energy of the reaction.The calculated activation energy by two iso-conversion rate methods,including the FWO method and DAEM,was similar to each other.The DAEM model,including the kinetic compensation effect,showed that the activation energy increased and then decreased as the conversion rate(α)increases,and reached the highest at α=40％～50％.
基金项目
国家自然科学基金(52176197)
国家自然科学基金(52100156)
国家自然科学基金(52322005)
中国科学院合肥大科学中心高端用户培育基金(2021HSC-UE006)
NETL
NSTL
万方数据