Abstract:

Polyolefin plastics account for more than half of the world's plastics and have an extremely long natural degradation time due to their stable hydrocarbon chain structure. The accumulation of plastic waste leads to serious environmental disasters such as "white pollution" and "microplastics". It is of great importance to focus on the chemical up-recycling of polyolefin waste. This paper summarized the characteristics of catalytic recycling of polyolefins including catalytic pyrolysis, hydrocracking and hydrogenolysis. An overview of the mechanism of formation of value-added products (e.g., aromatics, light olefins and lubricants) commonly used catalysts, and the relationship between structure and activity of catalysts in the cracking process was presented. Meanwhile, process intensification methods for producing high-value products were introduced, including intensification of the reaction process based on reactor design and intensification of the separation process based on the design of efficient separation materials. It was expected that controllable low-temperature pyrolysis and high-value recovery of waste polyolefins can be achieved through the development of high-efficiency catalysts and research on intensification technologies in reaction and separation processes.

Key words: waste polyolefin, chemical upgrade recycling, catalytic cracking, high-value utilization, process intensification

摘要：

占全球塑料产量一半以上的聚烯烃，由于其稳定碳氢链结构，极难降解，废弃后带来了严重的“白色”污染和“微塑料”问题。研究废弃聚烯烃的可控化学回收，实现其资源化和升级循环利用，具有重要的意义。本文重点总结了聚烯烃催化裂解的方法、特点及过程机理，包括催化热解、加氢裂化和氢解；梳理了高值裂解产物如芳烃、轻质烯烃、润滑油等的生成机制以及裂解过程中常用的催化剂种类及其催化构效关系；讨论和介绍了裂解反应以及高值产物生成的过程强化手段，包括基于反应器设计的反应过程强化、基于高效分离材料设计的分离过程强化等方面的研究进展。通过高效催化剂的设计及反应和分离过程强化技术的研究，有望实现废弃聚烯烃低温可控裂解及产物的高值化利用。

关键词: 废弃聚烯烃, 化学升级回收, 催化裂解, 高值化利用, 过程强化