Valorization of Garden Biomass and Plastic Waste into High-Calorific Biochar for Energy Co-Firing

¹ Institute of Sustainable Energy, Universiti Tenaga Nasional, 43000 Kajang, Selangor, Malaysia.
² Department of Mechanical Engineering, College of Engineering, Universiti Tenaga Nasional, 43000 Kajang, Selangor, Malaysia.
³ Faculty of Chemical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor, Malaysia
⁴ Department of Chemical and Environmental Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
⁵ Sustainable Process Engineering Research Centre, Faculty of Engineering, Universiti Putra Malaysia, 43000 UPM Serdang, Selangor, Malaysia.

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

This study examines the technical feasibility of co-processing garden waste with polyethylene (PE) waste in order to generate high-calorific biochar through slow pyrolysis at 500 °C for a duration of 60 minutes. Calorific value (CV) research revealed that the GW:PE biochar mix attained a maximum CV of 24.14 MJ/kg, with a fixed carbon content of 70.98% and a minimal ash level of 12.4%. These findings demonstrate a significant improvement in energy density and combustion properties relative to raw biomass. The energy performance of GW:PE biochar was benchmarked against Melawan sub-bituminous coal, demonstrating equivalent fuel quality and underscoring its appropriateness for co-firing applications. Proximate and final investigations confirmed the synergistic role of PE in improving biochar quality while preserving advantageous combustion characteristics. The results highlight co-pyrolysis as a viable method for waste valorization and sustainable bioenergy generation. This technique converts various waste streams into energy-dense solid fuels, adhering to circular economy principles and offering a viable alternative to fossil fuel reliance.