Comparative pyrolysis kinetics of oil palm biomass residues via thermogravimetric analysis (TGA)

Abstract

This study investigates the pyrolysis kinetics of three oil palm biomass residues, empty fruit bunch (EFB), mesocarp fiber (MF), and palm kernel shell (PKS), using thermogravimetric analysis (TGA). Model-free methods including Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO), along with the model-fitting Coats-Redfern (CR) approach, were employed to determine kinetic parameters. The maximum activation energies obtained were 213.38 kJmol⁻¹, 210.78 kJmol⁻¹, and 193.35 kJmol⁻¹, for EFB, MF and PKS respectively, using the KAS method at conversion factors of 0.7, 0.4, and 0.7, respectively. PKS demonstrated the lowest activation energy, indicating more favorable decomposition characteristics. The CR method revealed that first-order (F1) kinetics dominated the reaction mechanism for EFB and MF, while second-order (F2) kinetics prevailed for PKS, correlating with their respective cellulose and lignin contents. Among diffusion models, the three-way transport Jander equation (D3) exhibited the lowest activation energies (35.50–37.47 kJmol⁻¹), suggesting its significance in char combustion. These findings provide essential kinetic data for optimizing thermochemical conversion processes of oil palm biomass residues.