Exploring the potential of chemical recycling using a distributed model in the UK - A life cycle assessment perspective

Abstract

The study investigates the potential of chemical recycling of plastic waste in the UK, specifically through a small-scale, decentralised pyrolysis process that incorporates in-situ upgrading. With rising plastic production and limited capacity for mechanical recycling, chemical recycling (CR) emerges as a complementary solution for handling complex waste streams, such as multi-layered or contaminated plastics. The research focuses on the life cycle assessment (LCA) of a 165 kg/hr plant designed to convert mixed plastic waste (MPW) into naphtha, which can be used as a substitute of virgin petroleum feedstock in the production of plastic films. The LCA evaluates both waste and product perspectives, comparing chemical recycling with conventional waste management methods, including incineration with energy recovery (waste-to-energy) and a mixed end-of-life scenario (waste perspective) and with virgin plastic film (product perspective). Results show that chemical recycling significantly reduces climate change impacts-by 1284 kg CO₂-eq./tonne compared to waste-to-energy and by 430 kg CO₂-eq./tonne against the mixed end-of-life option. From the product perspective, chemically recycled naphtha results in up to 2977 kg CO₂-eq./tonne or 636 kg CO₂-eq./tonne lower impacts compared to virgin plastic production. The study highlights the use of small-scale, decentralised CR plants, however, challenges remain, such as the environmental impacts of by-products. The research concludes that chemical recycling offers a viable pathway to greenhouse gas emissions reductions compared to conventional waste management and virgin plastic production, albeit with interlinked trade-offs observable in other impact categories, highlighting that further optimisation and policy support are essential.