CHARACTERIZATION OF HYDROCARBON LIQUID BYPRODUCT FROM POLYETHYLENE WAX PRODUCTION: GC–MS COMPOSITION AND FUEL PROPERTY EVALUATION

The increasing production of polyethylene wax through thermal degradation of high-molecular-weight polyethylene generates a liquid hydrocarbon fraction as a by-product, the composition and potential utilization of which remain insufficiently studied. In the present work, the chemical composition and physicochemical properties of this liquid fraction were comprehensively investigated in order to evaluate its potential industrial applications. The sample was obtained during the thermal cracking of polyethylene and subsequently fractionated by atmospheric distillation up to 220 °C. Molecular composition was determined using gas chromatography–mass spectrometry (GC–MS), while fuel-related properties were evaluated through measurements of octane number, cetane number, and low-temperature characteristics according to relevant ASTM methods. GC–MS analysis revealed that the liquid fraction is predominantly composed of paraffinic hydrocarbons in the carbon number range C8–C26, with the major contribution originating from C10–C16 compounds. Linear alkanes were identified as the dominant components, accompanied by smaller amounts of branched alkanes and minor quantities of olefins formed during polyethylene chain scission. The obtained hydrocarbon distribution indicates that the investigated product belongs to the middle-distillate range typically associated with kerosene–diesel type fuels. Fuel property analysis showed that the liquid exhibits a cetane number of approximately 42, confirming its favorable ignition characteristics for compression ignition engines. Low-temperature measurements indicated a cloud point of −16 °C and a pour point of −27 °C, which are typical for paraffin-rich hydrocarbon mixtures. The results suggest that the investigated liquid fraction cannot be directly classified as a standard commercial fuel but may serve as a promising blending component for kerosene and diesel fuels after appropriate upgrading and purification. In addition to fuel applications, several alternative utilization pathways were identified, including use as an industrial solvent, feedstock for further cracking or pyrolysis processes, raw material for paraffin production, precursor for surfactants and synthetic lubricants, and potential heat-transfer fluid for industrial reactors. The findings highlight the potential of polyethylene cracking liquids as valuable secondary hydrocarbon resources and contribute to the development of more efficient and circular utilization strategies for polymer-derived hydrocarbon streams.