盐/碱热介质对聚乙烯废塑料热解特性的影响

Effect of Salt/Alkali Medium on Pyrolysis of Polyethylene Waste Plastics

为研究盐/碱热介质对高密度聚乙烯(HDPE)废塑料热裂解特性的影响,在废塑料中分别添加ZnCl_2、NaOHNa_2CO_3、KOH、ZnCl_2-KCI,以介质塑料质量比为4:1进行干混,利用热重(TG)分析技术研究了HDPE在不同介质中的热解过程,并采用Coats-Redfern法对HDPE废塑料的各热解过程进行线性拟合,然后通过线性回归曲线计算各热解过程的动力学参数。结果表明:盐/碱介质对HDPE的热解较为明显,使HDPE废塑料热裂解的失重区间变窄,最大失重温度降低,其中KOH对该热解反应的影响尤为明显;HDPE的各热解过程符合一级反应动力学;二元混合熔融介质比单组分熔融盐/碱更能降低反应的活化能。

To explore the influence of salt/alkali on the pyroiysis characteristics of HDPE,some salt/alkali,i.e.ZnCI_2,NaOH-Na_2CO_3,KOH,ZnCI_2-KCI,was added in the HDPE and mixed as a mass ratio of 4：1,and the pyroiysis process of HDPE pyroiysis in each medium was investigated by thermogravimetry（TG）technique.A Coats-Redfern method was used to linear fit each pyroiysis process of HDPE,and from the linear regression curve the kinetic parameters of the pyroiysis process can be obtained.The results show that：the thermal decomposition of HDPE is significantly reduced by the salt/alkali medium,which caused the loss of HDPE plastic waste to narrow,and the maximum weight loss temperature decreases,and the effect of KOH on the pyroiysis is obvious.The pyroiysis process of HDPE is in accordance with the first order reaction kinetics,and the activation energy of the two component mixed molten media is Iower than that of the single component molten salt/alkali.