The Influence of Heterogeneity of Polyolefin Waste and Alu-PEX Laminates on the Composition and Yield of Pyrolysis Gas: A Comparative Analysis with RDF

The composition and type of polymers used as feedstocks in the pyrolysis of plastic waste determine the decomposition process and the proportions of the final products. This paper examines the effect of feedstock heterogeneity on pyrolysis efficiency and pyrolysis gas composition. Four types of plastic waste were considered: real polyolefin waste of municipal origin, LDPE, Alu-PEX laminates, and an alternative refuse-derived fuel (RDF). Low-temperature pyrolysis (450 °C) was conducted in a laboratory reactor, and the gas composition was analyzed using GC-TCD/FID gas chromatography, which allowed for the determination of light hydrocarbons, oxygenates, and sulfur content. Compared to RDF, both municipal and LDPE polyolefin wastes produced gas with a higher calorific value and a predominance of light C1–C4 hydrocarbons, while Alu-PEX laminates produced gas rich in C1–C2 and low in sulfur, suitable for direct use. RDF was characterized by increased CO2 and non-flammable gas production and significantly higher sulfur content, requiring advanced purification. The results emphasize the importance of feedstock segregation and standardization and demonstrate that pyrolysis of polyolefins and Alu-PEX laminates can provide higher-quality energy gas than RDF, supporting the circular economy and energy self-sufficiency of industrial installations.