Continuous gasification-pyrolysis of fresh palm fruit bunches for biochar production and carbon sequestration

Abstract

The growing need for sustainable alternatives to fossil-derived heating motivates the development of biomass-based thermal systems for waste valorization. This study designed and operated a continuous pyrolysis system integrated with an updraft gasifier-syngas burner, using wood pellets as a renewable heat source to convert fresh palm fruit bunches (FFB) into valuable bio-products. The system replaced LPG heating, enabled direct utilization of undried FFB, and enhanced operational scalability. Stable operation was achieved at 1078 °C with low CO (280 mg Nm⁻³) and particulate emissions (56 mg Nm⁻³). Pyrolysis at 500 °C yielded biochar (9.5 wt%, HHV 28.1 MJ kg⁻¹, with 23 % carbon retention equivalent to 44.7 tCO<inf>2</inf>eq yr⁻¹), pyrolysis oil (21.9 wt%), wood vinegar (40.0 wt%), and gases (28.6 wt%). Techno-economic analysis indicated a net profit of 4.08 EUR h⁻¹ and a short payback period of 1.5–1.9 years. These findings demonstrate that the integrated biomass gasification-pyrolysis system offers a technically feasible and economically attractive solution for low-carbon conversion of palm residues into energy and carbon-rich materials.