Life-Cycle Analysis of Recycling of Post-Use Plastic to Plastic via Pyrolysis).

All of these outputs are contaminated with unwanted chemicals from the waste plastic feedstock or compounds formed in the pyrolysis process. Of these outputs generally only the pyrolysis oil is considered as a potential feedstock for plastic manufacture and must be subject to energy intensive and expensive clean-up and upgrading. [...] This leads to the formation of highly toxic compounds in the reactor such as PCDD/DF which can be carried through and contaminate the final hydrocarbon product whether it is fuel or feedstock for plastic production. [...] Pyrolysis oil or ‘pyroil’ derived from mixed, post-consumer plastic waste is a complex mix of hydrocarbons heavily contaminated with chemicals from the plastic waste feedstock to the pyrolysis plant, as well as a range of other contaminants formed in the pyrolysis process under heat and pressure. [...] - Claims of reduced GHG emissions for pyrolysis derived plastic rely heavily on counterfactual arguments about GHG savings from not sending the plastic waste to traditional end of life (EOL) disposal options – i.e. landfill and incineration. [...] 2017) conducting an LCA on the conversion of plastic waste to fuel using pyrolysis. This study was also funded by the American Chemistry Council and many of its assumptions with respect to GHG emissions are used as the basis for this study. [...] The plastics and chemical industry have been heavily promoting the use of highly flexible Mass Balance allocation schemes to claim determined recycled content of final plastic products made using a fraction of pyrolysis oil. [...] The only current identified uses of pyrolysis wax from plastic waste are asphalt additives for pavement construction and potential feedstock to manufacture chemicals (Ong et al. 2023). [...] Char is also produced as a residual and may account for 10% of the initial input. [...] They even allocate GHG savings in their counterfactual assessment for mixed plastic waste GHG emissions avoided by sending the waste to pyrolysis plants and not to traditional EOL management such as landfills and incinerators. However, pyrolysis plants have technical limitations on the types of plastic they can accept, and this common claim is now totally refuted, by both independent authors a [...] However, and a perfect example of the imbalance within the study, no consideration or assessment is given to practical EOL management for the residues from the pyrolysis process. These solid wastes are mainly hazardous waste (IPEN/Beyond Plastic 2023).