Thermally Responsive Supports for Enhanced Efficiency in PET Depolymerisation

热响应支撑可提高 PET 解聚效率

• 批准号: EP/Y003667/1
• 负责人: Joseph Wood
• 金额: $ 117.7万
• 依托单位: University of Birmingham
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FY003667%2F1
• 关键词: Thermally; Responsive; Supports; Enhanced; Efficiency

There is an urgent need to devise processes for recycling plastics, with an estimated 460 million metric tonnes of plastics being utilised worldwide in 2019 alone, of which only 10% is recycled globally, the remainder going to incineration, landfill or export. Burning of polymers contribute to CO2 production, causing global warming, and pollution of rivers and oceans occurs through discarding to the environment. Current mechanical and thermal recycling techniques can be used to produce lower grade products such as clothing, insulation, garden and road furniture, but these have inferior colour or mechanical properties, in comparison to virgin polymer, necessitating chemical recycling to produce virgin monomer. The principal polymer selected for study in this proposal is PET, with its wide industrial and consumer applications in bottles, packaging and clothing. In the USA 30 % of PET is currently recycled, in the EU the figure is 52 %, whilst world demand for PET resin is ~23.5 million tonnes and production capacity ~30.3 million tonnes, making a potentially large feedstock for recycling. Virgin PET resin has a much higher value at £1084/tonne compared with used PET bottles priced at £222.50/tonne, making chemical recycling to produce the virgin polymer the more economically attractive route than mechanical or thermal recycling. Chemical recycling of PET can follow a number of routes including reaction with alcohols, glycols, amines and ammonia, sometimes catalysed by basic materials like sodium bicarbonate, or more recently developed ionic organocatalysts or metal salt/organic base dual catalysts. However potential scale up for industrial production is hampered by the difficulties of separating the catalyst from the product mixture and efficient recycling. Also, there is a need to isolate and purify the product BHET from a mixture which may contain contaminants from the polymer, including dyes and additives. This proposal aims to create solutions to these problems by developing supported catalysts and separation technologies to enable a scaled-up process for PET depolymerisation, which could potentially be deployed industrially. Catalyst supports will be developed based on thermally responsive polymers, which can be solubilised to contact the reacting mixture, or solidified via simple temperature cycling to aid recovery by filtration. Key considerations will include understanding the reaction kinetics of the system, including any mass transport resistances, and optimisation of reaction conditions to achieve an attractive rate of reaction. We will experiment with polymer structures to find the optimal catalyst/support combination. In addition to catalyst recovery by temperature cycling, we will study recovery of BHET product via membrane separation. Strategies will include testing of commercial membranes and development of mixed matrix membranes incorporating zeolites to enhance the permeate flow. The proposed technologies will provide more attractive and commercially viable solutions for chemical recycling. In order to realise the benefits of the research, we have engaged Project Partners from across the recycling and polymer production sectors including Dupont Teijin Films and Siemens PSE, and academic collaborator Pennsylvania State University. They will provide, or advise on, samples for depolymerisation, provide software, technical consultation on the work plan, access to facilities and advise on routes to commercialisation and impact delivery as outlined in their letters of support.

迫切需要设计回收塑料的工艺，仅 2019 年，全球就估计使用了 4.6 亿吨塑料，其中只有 10% 在全球范围内回收，其余的则用于焚烧、填埋或燃烧聚合物。产生二氧化碳，导致全球变暖，并且通过丢弃到环境中而污染河流和海洋。目前的机械和热回收技术可用于生产低等级产品，例如服装、绝缘材料、花园和道路家具，但与原始聚合物相比，它们的颜色或机械性能较差，需要化学回收来生产原始单体。本提案中选择用于研究的主要聚合物是 PET，其在瓶子、工业和消费领域有着广泛的应用。目前，美国 30% 的 PET 被回收利用，欧盟这一数字为 52%，而世界对 PET 树脂的需求量约为 2,350 万吨，产能约为 3,030 万吨，是一种潜在的巨大原料。与每吨 222.50 英镑的废旧 PET 瓶相比，原生 PET 树脂的价值要高得多，为 1084 英镑/吨，这使得化学回收生产原生聚合物比机械或热回收更具经济吸引力。 PET 可以遵循多种途径，包括与醇、二醇、胺和氨反应，有时由碳酸氢钠等基本材料或最近开发的离子有机催化剂或金属催化然而，从产物混合物中分离催化剂和有效回收的困难阻碍了工业生产的潜在规模化。此外，需要从可能含有BHET的混合物中分离和纯化产物。该提案旨在通过开发负载型催化剂和分离技术来解决这些问题，从而扩大 PET 解聚工艺的规模，从而有可能在工业上得到应用。将基于热响应聚合物进行开发，该聚合物可以溶解以接触反应混合物，或通过简单的温度循环固化以帮助通过过滤进行回收。关键考虑因素将包括了解系统的反应动力学，包括任何传质阻力。优化反应条件以实现有吸引力的反应速率。除了通过温度循环回收催化剂外，我们还将研究通过膜分离回收 BHET 产品。策略将包括测试商业膜和开发包含沸石的混合基质膜以增强渗透液流量。所提出的技术将为化学回收提供更具吸引力和商业上可行的解决方案。来自回收和聚合物生产领域的合作伙伴，包括杜邦帝人薄膜和西门子 PSE，以及宾夕法尼亚州立大学的学术合作者，他们将提供解聚样品或提供建议，并提供有关工作的软件和技术咨询。如支持信中所述，规划、使用设施并就商业化途径和影响力交付提供建议。