Co-combustion performance of oil palm biomass with coal: thermodynamics and kinetics analyses

Abstract

This paper comprehensively assesses oil palm biomass and coal blends, focusing on evaluating thermodynamic and kinetics parameters. The experimental approach employs thermogravimetric differential thermal analysis (TG–DTA) with varying heating rates of 5, 10, 15, and 20 K min⁻¹. Laboratory tests are conducted on six blended samples of different coal and oil palm biomass ratios. The evaluation encompasses key combustion parameters, including ignition index (D_i), burnout index (D_b), combustion performance index (S), reactivity (R), flammability index (C), and index of intensity (H_f). Additionally, thermodynamic parameters such as a change in enthalpy (ΔH), change in Gibbs free energy (ΔG), and change in entropy (ΔS) are analyzed. The results demonstrate that the optimal co-combustion material is a blend of 76% low-rank coal, 19% medium-rank coal, and 5% oil palm fronds, identified as L80M20F. This blend exhibits superior combustion performance, as evidenced by the highest values for D_i (31.17 × 10^–8% min⁻³), D_b (28.91 × 10^–11% min⁻³ K⁻¹), and R (39.18 × 10⁴ mg min⁻¹). Furthermore, it displays the lowest ΔH of 73.11 kJ mol⁻¹ and ΔS of − 0.0452844 J mol⁻¹ K⁻¹, along with the highest ΔG of 179.77 kJ mol⁻¹. The accuracy of these findings is confirmed through verification with the Gram–Charlier peak function, which yields a negligible margin of error. In conclusion, this study provides crucial insights for decision-makers by assessing combustion and thermodynamic parameters of oil palm biomass and coal blends. The L80M20F, identified as the optimum blended fuel, showcases its potential to enhance combustion efficiency and contribute to the energy transition toward net-zero emissions.