Due to their many, varied and valuable properties plastics are used in almost every area of modern society. Despite this, the use of plastics comes with two key concerns: the dependency of plastics on finite fossil fuels and the generation of plastic waste which, when improperly managed, pollutes the environment, harms wildlife, and represents significant economic resource loss. A proposed solution is to transition to a plastics circular economy. In a circular economy, waste is phased out; materials are kept in use, and natural systems are regenerated. In the context of plastic waste, chemical recycling processes have the potential to support a circular economy. Chemical recycling processes recycle plastics which cannot be recycled via established methods. The processes also produce valuable hydrocarbon chemicals, which can be used to manufacture new plastics, avoiding the need for virgin fossil fuels. In addition to the concerns around plastic use and waste, there are many other sustainability concerns facing humankind. In particular, the impact of climate change. In this thesis, Life Cycle Assessment (LCA) was used to explore the potential of chemical recycling implementation in future plastic waste management systems. The research presented here found that chemical recycling will likely have a lower climate change impact than current landfill and incineration options for plastics. As well as produce potentially valuable chemicals which could replace fossil fuels. Thus, supporting sustainable, circular system development. However, chemical recycling processes rely heavily on fossil fuel combustion to supply process heat. In addition, the technology currently requires specific plastic mix compositions to operate optimally. Thus, future R&D should focus on alternative heat supplies and reducing the sensitivity of the recycling process to plastic waste variations. This thesis emphasised the importance of holistic, systems thinking in technology development. It was concluded that sustainability issues should not be addressed in isolation because complex systems with multiple variables (e.g. fuel type, technology availability and economics) influence the effectiveness of circular economies. Therefore, a holistic systems thinking approach is essential to securing the transition to a sustainable, circular economy.
Chemical Recycling of Plastic Waste: A Life Cycle Approach: (Alternative Format Thesis)
Furlong, R. (Author). 11 Oct 2023
Student thesis: Doctoral Thesis › PhD