Biofuel production using tire waste in fast pyrolysis: A life cycle assessment study

Despite exceeding 2 billion units annually, the management of waste tires remains a global challenge. Pyrolysis, a thermochemical conversion process, offers a potential waste-to-energy solution with valuable byproducts. However, concerns regarding its environmental sustainability, particularly emissions associated with sulfur content, persist. The aim of this study is to evaluate the environmental impacts of a large-scale pyrolysis reactor processing waste tires using life cycle assessment (LCA) as an environmental impact tool. In this study, using heating fuel oil (HFO) and non-condensable gas (NCG) as heating methods, two pyrolysis scenarios were investigated in terms of their environmental performance. The LCA identified abiotic depletion and acidification as key environmental concerns. The HFO scenario has shown a 15% greater impact on abiotic depletion and a 78% greater impact on acidification compared to the NCG scenario. This difference has been attributed to the higher sulfur content in HFO. Nevertheless, both pyrolysis scenarios have shown positive environmental benefits regarding marine and freshwater ecotoxicity compared to conventional alternatives. These findings support the potential of pyrolysis for sustainable waste tire management while highlighting the need for further optimization to minimize sulfur-related emissions. The findings of this study can be used as a roadmap towards adapting clean technologies such as pyrolysis as a waste management strategy for policymakers by applying holistic system boundaries and regulated pyrolysis production.