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Maximising naphtha-range hydrocarbons from thermal pyrolysis of polyolefin-rich mixed plastic waste by split-plot response surface methodology

Year: 2025
Type: article
Abstract: The pyrolysis of polyolefin (PO)-rich mixed plastic waste represents a promising pathway for recycling plastic waste into liquid hydrocarbons, particularly in the naphtha range, for use as a refinery input. However, assessments of naphtha production from complex plastic waste remain limited. This work systematically investigates the batch pyrolysis of a PO-rich mixed plastic waste derived from a sorted household waste stream (DKR-350) using Design of Experiments (DoE) and response surface methodology (RSM). Oil yield, naphtha-range hydrocarbon yield, and other responses were modelled as functions of relevant processing parameters, such as batch time, temperature, and plastic pre-treatment method. Experiments were conducted in a batch autoclave under various process conditions (380–450 °C, 0–4 h, with varying feedstock pre-treatments, gas types, and pressures). Time and temperature were the most critical factors for achieving the highest oil yield (73% at 420 °C and a batch time of 2.6 h). The highest naphtha yield in the experimental design range was 42% (448 °C, 3.1 h), achieved using a feedstock that had been pre-treated by dry-washing. Additionally, this work gives key insights into the pyrolysis mechanism of plastic waste. For instance, the formation of CO and CO 2 was linked to the presence of specific biogenic and non-polyolefinic impurities at various stages during pyrolysis. The composition of the naphtha fraction also becomes increasingly richer in C 5 -C 9 as pyrolysis severity increases. This work explores the potential of pyrolysis as part of the solution to global plastic waste challenges within a more circular economy.
DOI: 10.1016/j.wasman.2025.115094
Language: English
Open Access status: hybrid
Estimated APC paid: $4,450
OpenAlex ID: W4413866699
FWCI: 1.421
Cites: 47
Cited by: 6
Related to: 10