Plastics are common in our daily lifestyle, notably in the packaging of goods to reducing volume, enhancing transportation efficiency, keeping food fresh and preventing spoilage, manufacturing healthcare products, preserving drugs and insulating electrical components. Nonetheless, massive amounts of non-biodegradable plastic wastes are generated and end up in the environment, notably as microplastics. The worldwide industrial production of plastics has increased by nearly 80% since 2002. Based on the degree of recyclability, plastics are classified into seven major groups: polyethylene terephthalate, high-density polyethylene, polyvinyl chloride, low-density polyethylene, polypropylene, polystyrene and miscellaneous plastics. Recycling technologies can reduce the accumulation of plastic wastes, yet they also pollute the environment, consume energy, labor and capital cost. Here we review waste-to-energy technologies such as pyrolysis, liquefaction and gasification for transforming plastics into clean fuels and chemicals. We focus on thermochemical conversion technologies for the valorization of waste plastics. This technology reduces the diversion of plastics to landfills and oceans, reduces carbon footprints, and has high conversion efficiency and cost-effectiveness. Depending on the conversion method, plastics can be selectively converted either to bio-oil, bio-crude oil, synthesis gas, hydrogen or aromatic char. We discuss the influence of process parameters such as temperature, heating rate, feedstock concentration, reaction time, reactor type and catalysts. Reaction mechanisms, efficiency, merits and demerits of biological and thermochemical plastic conversion processes are also discussed.

塑料在我们的日常生活中很常见，尤其是在货物包装中，以减小体积，提高运输效率，保持食物新鲜和防止变质，制造保健产品，保存药物和绝缘电气组件。尽管如此，仍然产生了大量不可生物降解的塑料废料，并最终进入环境，特别是作为微塑料。自2002年以来，全球塑料工业产量增长了近80％。根据可回收程度，塑料可分为七个主要类别：聚对苯二甲酸乙二酯，高密度聚乙烯，聚氯乙烯，低密度聚乙烯，聚丙烯，聚苯乙烯和杂项塑料。回收技术可以减少塑料废物的积累，但它们也污染环境，消耗能源，人工和资本成本。在这里，我们回顾了将热能转化为清洁燃料和化学制品的热能转化，液化和气化等废物转化为能源的技术。我们专注于热化学转化技术，用于废塑料的增值。这项技术减少了塑料向垃圾填埋场和海洋的转移，减少了碳足迹，并具有很高的转换效率和成本效益。根据转换方法的不同，塑料可以选择性地转换为生物油，生物原油，合成气，氢气或芳烃。我们讨论了温度，加热速率，原料浓度，反应时间，反应器类型和催化剂等工艺参数的影响。反应机理，效率，