外卖塑料包装热解动力学研究——基于无模型和模型拟合法

在非等温条件下对外卖包装中的塑料组分进行热重实验，结果显示单组分聚丙烯（PP）、高密度聚乙烯（HDPE）和聚苯乙烯（PS）及其混合物（PP/HDPE/PS）的热解过程一步完成.针对混合塑料的复杂热解反应过程，提出了一种无模型方法和模型拟合法结合逐步获得完整动力学参数的方法，使结果更具可信度.采用无模型方法（K-A-S、F-W-O和Starink）研究了单组分及其混合物热解过程的动力学参数，得到PP、HDPE、PS和PP/HDPE/PS热解过程的平均活化能（E）分别为224.7，238.5，194.1和179.3kJ/mol.在升温速率为20K/min条件下，以无模型方法得到的活化能和模型拟合法（Malek和C-R）结果作为逻辑判定依据，总结了单组分及其混合物的热解机理均属于随机成核随后生长.分析了动力学参数间存在的补偿效应，并构建了补偿效应方程.本论文的研究可为外卖塑料垃圾热解工艺参数的优化和热解反应器的设计提供有力的支撑.

Pyrolysis kinetics study of takeaway plastic packaging—Based on model-free and model-fitting method

Thermogravimetric analysis for components of takeaway plastic packaging was carried out under non-isothermal conditions. The results showed that the pyrolysis processes of the single components of PP, HDPE, PS, and the mixture (PP/HDPE/PS) were finished in one step. For the complex pyrolysis reaction with mixed plastics, a model-free method combined with the model-fitting method was proposed to obtain the complete set of kinetic parameters, which made the results more reliable. The kinetic parameters of a single component and the mixture in the pyrolysis process were studied with model-free methods (K-A-S, F-W-O and Starink). In pyrolysis processes, the average activation energy (E) of PP, HDPE, PS and PP/HDPE/PS reached 224.7, 238.5, 194.1 and 179.3kJ/mol, respectively. Based on the activation energy obtained by the model-free method and the results of model fitting (Malek and C-R), the pyrolysis mechanism of a single component and the mixture was random nucleation followed by growth when the heating rate was 20K/min. Moreover, the compensation effect between the kinetic parameters was analyzed to establish the compensation effect equations. This study can provide support for the optimization of the pyrolysis process parameters of takeaway plastic waste and the design of the pyrolysis reactor.