Unlocking Hydrocarbon Potential from Metallized Multi-Layer Plastics: A Kinetic and Product Evolution Study

This study explores the thermal decomposition behavior, kinetic parameters, and product evolution of metallized multi-layered plastics (MLPs). Thermogravimetric analysis (TGA) revealed a three-stage, diffusion-controlled decomposition process, best described by the three-dimensional Ginstling–Brounshtein model, attributable to the complex layered structure of MLPs. The apparent activation energy ranged from 183.47 to 218.42 kJ mol⁻¹, higher than that of polypropylene (PP), high-density polyethylene (HDPE), polystyrene (PS), and polyurethane (PU), but lower than polyamide (PA) and polyethylene terephthalate (PET). The maximum decomposition rate occurred between 457.10°C and 486.63°C, following first-order kinetics. Pyrolysis at 500°C yielded a fuel oil, which, after hydro-processing, produced hydrocarbons in the C₅–C₄₀ range, with 97.55% falling within the C₅–C₁₈ fraction, comprising 45.72% paraffins and 37.80% aromatics. Densification of MLPs effectively suppressed the carryover of metallized layers, while chemical treatment removed suspended carbon and reduced fuel oil viscosity before hydro-processing. These findings elucidate the decomposition and product formation mechanisms of metallized MLPs and offer a comparative evaluation against conventional plastics (types 1–7) concerning fuel oil yield and composition.