Abstract

This study examines the optimal conditions and effective heat integration strategies for the synergistic co-pyrolysis of oil palm empty fruit bunches (EFB) and rubber wood sawdust (RWS), with a focus on sustainable energy recovery and waste valorization. Optimal co-pyrolysis parameters, determined via response surface methodology (RSM), were identified as a temperature of 850 °C, biomass particle size of 0.35 mm, and an EFB-to-RWS ratio of 55:45, achieving a maximum non-condensable gas (NCG) yield of approximately 57 % by weight. NCG exhibited notable heating values between 10.36 and 18.73 MJ/m³, with the highest HHV (18.73 MJ/m³) obtained at 850 °C for pure EFB at 0.85 mm particle size, though yielding a comparatively lower NCG mass fraction (∼46 %). Aspen Plus simulations validated these experimental results and demonstrated significant efficiency improvements through heat integration. Specifically, internal heat recovery via a heat exchanger significantly reduced external heating requirements from 537.64 kW to merely 7.64 kW, and cooling demands from − 595.55 kW to − 65.55 kW. The NCG stream, produced at a volumetric flow rate of approximately 0.3287 m³/s (863.52 kg/h), offered substantial surplus energy potential (3,405–6,157 kW), highlighting its suitability for clean combustion, combined heat and power generation, and district heating applications. Overall, the integrated approach confirms co-pyrolysis as a highly adaptable, efficient, and environmentally favorable method, aligned closely with circular economy principles and flexible biomass resource management.