Co-pyrolysis of oil palm empty fruit bunch and polypropylene: Synergistic effects on blending ratios and product quality

¹ Department of Mechanical and Biosystem Engineering, Faculty of Agricultural Engineering and Technology, IPB University (Bogor Agricultural University), IPB Darmaga Campus, PO BOX 220, Bogor, West Java 16680, Indonesia.
² Research Center for Energy Conversion and Conservation, National Research and Innovation Agency (BRIN), Indonesia

^* Corresponding author: novi024@brin.go.id; obiefarobie@apps.ipb.ac.id

Abstract

The increasing accumulation of oil palm empty fruit bunches (EFB) and polypropylene (PP) waste necessitates sustainable management solutions. This study investigates the co-pyrolysis of EFB and PP in a fixed-bed reactor at temperatures ranging from 400 to 600 °C, utilizing blending ratios of 100:0, 75:25, 50:50, 25:75, and 0:100. The results revealed notable synergistic effects, particularly at a 75:25 EFB:PP ratio, which yielded 50.35% bio-oil, the highest gas yield (28.95%), and reduced biochar formation compared to pure EFB. The bio-oil composition showed increased aliphatic compounds and reduced oxygenated compounds, making intermediate ratios such as 75:25 ideal for balancing hydrocarbons and oxygenates. The char derived from co-pyrolysis maintained adequate porosity for applications such as adsorption, catalysis, and energy storage. Gaseous products such as CO₂, methane, and ethylene demonstrate a high energy potential, underlining the suitability of co-pyrolysis for industrial and energy applications. These findings confirm that co-pyrolysis is an efficient waste-to-resource strategy, optimizing bio-oil, char, and gas quality while addressing both biomass and plastic waste challenges.