Wu Yunfei, Wang Kechao, Wei Baoyong, Yang He, Jin Lijun, Hu Haoquan
State Key Laboratory of Fine Chemistry, Institute of Coal Chemical Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China.
State Key Laboratory of Fine Chemistry, Institute of Coal Chemical Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China.
Sci Total Environ. 2022 Feb 1;806(Pt 3):151287. doi: 10.1016/j.scitotenv.2021.151287. Epub 2021 Oct 28.
Catalytic fast pyrolysis experiments of low-density polyethylene (LDPE) over HZSM-5 were carried out by using infrared heating technology. The effects of heating rate (1-30 °C/s), pyrolysis temperature (450-650 °C), and mass ratio of catalyst to LDPE (0:100 to 50:100) on product distribution and oil composition in LDPE pyrolysis were investigated, and the fast pyrolysis mechanism was explored. The results indicated that a higher heating rate, namely 20 °C/s, can remarkably enhance the liquid oil yield (93.42%), but the oil is heavy due to about 90% high‑carbon n-aliphatics. The addition of HZSM-5 performed an excellent effect on obtaining high-quality liquid oils, among which the total content of monocyclic aromatic hydrocarbons (MAHs) and iso-aliphatics obviously increase from 0.68% to 70.26%. The optimal HZSM-5/LDPE ratio of 10:100 was identified by considering the cost-effective factor. Furthermore, the lower catalytic temperature is favorable to the generation of light oil components, especially MAHs. The feasible generation paths were proposed, which mainly derived from the secondary reaction of the intermediate formed by initial chain cleavage including cyclization, aromatization, Diels-Alder reaction, as well as isomerization.
采用红外加热技术，在HZSM-5上进行了低密度聚乙烯（LDPE）的催化快速热解实验。考察了加热速率（1-30℃/s）、热解温度（450-650℃）和催化剂与LDPE的质量比（0:100至50:100）对LDPE热解产物分布和油相组成的影响，并探讨了快速热解机理。结果表明，较高的加热速率，即20℃/s，可显著提高液体油产率（93.42%），但由于约90%的高碳正构脂肪烃，油品较重。HZSM-5的加入对获得高质量液体油具有优异效果，其中单环芳烃（MAHs）和异构脂肪烃的总含量从0.68%显著增加至70.26%。综合考虑成本效益因素，确定了最佳的HZSM-5/LDPE比例为10:100。此外，较低的催化温度有利于轻质油组分的生成，尤其是MAHs。提出了可行的生成路径，主要源于初始链断裂形成的中间体的二次反应，包括环化、芳构化、狄尔斯-阿尔德反应以及异构化。
