Development of an innovative microwave-based process for recycling end-of-life PVC

卤化塑料如聚氯乙烯是用途广泛的高通用性聚合物。聚氯乙烯占全球塑料总产量的20%。然而，它们的有用特性（如耐用、不导电、耐化学腐蚀）也意味着它们在使用寿命结束后的回收尤其具有挑战性。机械回收是一种低成本的选择，但由于材料的降解，只有有限的回收是可能的。由于高腐蚀性的酸性副产物，PVC目前被排除在化学回收之外，这是一个重大的工艺工程挑战。此外，用于调节pvc性能的添加剂和增塑剂的范围增加了复杂性。因此，在英国，每年约有46万吨pvc垃圾被焚烧或送往垃圾填埋场。最近的法规变化禁止来自垃圾填埋场或焚烧的持久性有机污染物，加上塑料包装税的引入，意味着废物处理者和塑料生产商都迫切需要回收PVC的化学过程。该项目将引领英国首个PVC处理化学回收工厂的发展，以应对不断增长的PVC废物量。Halocycle将开发一种创新的微波热解工艺，用于将PVC解聚成其组成单体。非金属工艺部件本身具有耐酸性能，克服了处理酸性副产物的工程挑战。该工艺将使用电缆颗粒pvc废料原料进行演示，这些废料是从电缆金属提取加工中回收的，目前是不可回收的，作为一个潜在的下游加工步骤，整合到当前的回收工厂工艺中。技术经济分析将验证工艺放大的技术性能和经济效益，支持建立示范工厂以实现该工艺商业化的投资决策。PVC加工成其组成单体为塑料生产提供了有价值的化学基石的可持续供应，避免了对基于化石燃料的替代品的依赖，支持循环经济方法。

Halogenated plastics such as PVC are highly versatile polymers used in a wide range of applications. PVC represents ~20% of all plastics manufactured globally. However, it is their useful properties (e.g. durable, non-conductive, chemically resistant) that also mean they are particularly challenging to recycle at end-of-life. Mechanical recycling is a low-cost option, but due to degradation of material, only a limited number of recycles are possible. PVC is currently excluded from chemical recycling due to the highly corrosive acidic by-products which present a significant process engineering challenge. In addition, the range of additives and plasticisers used to modulate PVCs properties increase complexity. As a result, each year in the UK, ~460,000 tonnes of PVC-waste is incinerated or sent to landfill.Recent regulatory changes prohibiting persistent organic pollutants from landfill or incineration plus introduction of the Plastics Packaging Tax means a chemical process for recycling PVC is urgently needed by both waste handlers and plastic producers.This project will lead the development of the UK's first chemical recycling plant for PVC-processing in response to growing volumes of PVC waste. Halocycle will develop an innovative microwave-pyrolysis process for depolymerisation of PVC into its constituent monomers. Non-metallic process components that are inherently acid-resistant overcome the engineering challenges with handling acidic by-products. The process will be demonstrated using cable granule PVC-waste feedstocks recovered from electrical cable metal extraction processing, currently not recyclable, as a potential downstream processing step for integration into current recycling plant processes.Technoeconomic analysis will validate technical performance and economics of process scale-up, supporting investment decision for a demonstration plant build towards commercialisation of the process. Processing of PVC into its constituent monomers provides a sustainable supply of valuable chemical building blocks for plastic production avoiding reliance on fossil-fuel based alternatives supporting a Circular Economy approach.