木质素与高密度聚乙烯共热解特性研究

生物质与塑料共热解是一种非常有效的生物质利用方法之一,但由于生物质结构的复杂性,共热解过程的机理尚不明晰。木质素是生物质的主要组分之一,本文通过热重-质谱联用仪和裂解器-气相色谱质谱仪研究其与高密度聚乙烯共热解过程,获取共热解特性及热解产物分布特性,以揭示共热解过程机制。结果显示,木质素与高密度聚乙烯共热解过程存在协同效应,使得热解失重速率加快,热解固体残渣含量减少。共热解过程有利于CH₄、H₂O、CO和C₂H₄的生成,抑制CO₂的生成。同时,酚类、醇类和糖类等含氧化合物产量减少,烷烃和烯烃类化合物产量增加。结果表明,共热解过程会发生氢转移现象,氢与木质素衍生热解产物结合发生反应,从而抑制含氧化合物的生成,促进烷烃类和烯烃类化合物生成。

Study on the Co-Pyrolysis Characteristics of Lignin and High-Density Polyethylene

The co-pyrolysis of biomass and plastics is one of the most effective methods of biomass utilization, while the mechanism of the co-pyrolysis process is still unclear due to the complexity of the biomass structure. In this work, the co-pyrolysis process of lignin (one of the main components of biomass) and high-density polyethylene was studied by thermogravimetric mass spectrometer and pyrolysis-gas chromatography coupled to mass spectrometer. The co-pyrolysis characteristics and pyrolysis product distribution were obtained, and the mechanism of co-pyrolysis process was also proposed. The results showed that a synergistic effect existed in the co-pyrolysis process of lignin and high-density polyethylene, which accelerated the rate of weight loss and reduced the content of pyrolysis solid residues. And the co-pyrolysis process was conducive to the formation of CH₄, H₂O, CO and C₂H₄, while inhibited the formation of CO₂. At the same time, the yields of oxygenated compounds such as phenols, alcohols and sugars decreased, and the yields of alkanes and alkenes increased. The above results indicated that hydrogen transfer could occur in the co-pyrolysis process, and hydrogen would react with the lignin-derived pyrolysis products, thereby inhibiting the generation of oxygenated compounds and promoting the production of alkanes and alkenes.