Thermal and Catalytic Pyrolysis of Real Plastic Solid Waste as a Sustainable Strategy for Circular Economy

The management of plastic waste is a serious environmental problem, therefore numerous strategies have been explored to reuse/recover these materials, avoiding their disposal in landfills. In particular, research has focused on thermochemical conversion processes and especially on pyrolysis processes. Therefore, in this study, a real Plastic Solid Waste (PSW) from COREPLA (Italian national consortium for collection, recycling, and recovery of plastic packaging), deprived of PET, PVC, and PTFE was used as feedstock for batch thermal and catalytic pyrolysis tests. The experiments were performed in a micro-reactor under nitrogen flow, using ɣ-alumina as catalyst. The effects of a variation in pyrolysis temperature (450–650°C) on the gaseous, condensable, and solid products were assessed. The thermal and catalytic pyrolysis tests of LDPE at 550°C were also investigated, as a representative surrogate of the plastics materials found in PSW. Preliminary results highlight that gas and condensate yields increase with pyrolysis temperature (with or without γ– alumina). The condensate products of all experiments were an oily wax made up mainly of long-chain aliphatic hydrocarbons (mostly diesel-like fraction, C12-C20). The qualitative composition of gaseous and condensable products differs between thermal and catalytic tests. However, the alumina leads to a higher formation of aromatic hydrocarbons.