From waste heterogeneity to circular resources: A review of thermal and catalytic pyrolysis of mixed and contaminated plastics

Résumé fourni par la source

In real-world waste streams, plastics are intermixed and contaminated with food residues, paper fibers, biomass, fillers, metals, dyes, and multilayer packaging, which constrains mechanical recycling. Pyrolysis is the principal thermochemical route proposed for these streams, and catalytic pyrolysis is credited with an impurity tolerance that proves conditional and feed-specific rather than general. This review organizes the evidence into a chain from feed heterogeneity to circular-resource suitability and grades it across six dimensions, including reporting completeness and feed realism. Catalysts are assessed on measured state, deactivation and regeneration, and products on declared reporting bases rather than headline yields. Within the assembled evidence, controlled dose-response studies quantify product responses but not measured catalyst state or contaminant-specific deactivation. Two findings follow. Reported yields are frequently not comparable because feed and product bases, mass-balance closure conventions, and the treatment of gas and catalyst mass differ across studies and are often undeclared, and two widely cited additive-deviation results are not reproducible from their own sources. And a produced liquid is not yet a circular resource: on real contaminated feeds, high yield and high heating value coexist with certified-method specification failures and with contaminant concentrations exceeding compiled industrial thresholds by one to four orders of magnitude, so product suitability must be assessed separately from product quantity. Implementation therefore depends on end-use-specific acceptance requirements, chain-of-custody attribution, conditional alignment with the Sustainable Development Goals, and the carbon intensity of process energy and hydrogen rather than on liquid yield.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.