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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 (Di), burnout index (Db), combustion performance index (S), reactivity (R), flammability index (C), and index of intensity (Hf). 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 Di (31.17 × 10–8% min−3), Db (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. [ABSTRACT FROM AUTHOR]

Coal is the primary fuel for most Indonesian power plants, causing high CO2 emissions. Since the Paris Agreement prioritizes efforts to reduce CO2 emissions, power generation companies have put great efforts into demonstrating co-firing of coal with biomass. This research is the first study to examine the synergistic effect of combining coal and sorghum during co-firing. To complete this investigation, an experimental setup was carried out utilizing a drop tube furnace equipment that creates ash deposits, followed by X-ray diffraction (XRD) analysis to acquire the crystallinity parameters and characterization. Based on the parameters of derivative thermogravimetry, Rmax, sample residue, root mean square of synergistic occurrence, ash deposit, insufficient crystallinity, amorphous content, and crystal structure, namely C5, C10, C15, C20, and C25 (representing the sorghum ratios of 5 10, 15, 20, and 25%, respectively), the grey relational grade analysis provides recommendations for the implementation of a mixture of coal and sorghum co-firing. The thermogravimetric analysis revealed that 10% of sorghum in the fuel mixture (namely C10) was the best recommendation for mixing with coal in terms of the activation energy (111 kJ mol−1) with an error deviation close to zero. Overall results from thermogravimetric to XRD analyses indicate recommendations for co-firing coal and sorghum in the sequence of C10, C15, C5, C25, and C20. [ABSTRACT FROM AUTHOR]

[Display omitted] • Calliandra calothyrsus and Gliricidia sepium are promising source for biomass fuel. • Combustion characteristics and ash-related issues are investigated. • Gliricidia sepium has better combustion performance than Calliandra calothyrsus. • Ash deposits of both woody biomasses are dominated by Ca, K, and S elements. • Several aggregate particles and low melting minerals are observed. Calliandra calothyrsus and Gliricidia sepium are developed as wood energy forest plantations in degraded land. They have good survivability, are fast to be harvested, and have good calorific value to be utilized as biomass fuel. This study aims to investigate their combustion characteristics by thermogravimetric analysis and their ash-related issues by combustion experiments in drop tube furnace and ash observation. The results show that G. sepium has a better combustion performance with higher values of ignition index, comprehensive combustion index, and flammability index, while C. calothyrsus shows better ash-related issues with less risk in theoretical slagging prediction, clearer metal surface in the fouling area, and less ash deposit formation. The domination of K, Ca, and S elements in the ash deposits of both biomasses results in several sticky aggregate particles and low-melting minerals. This study provides an in-depth understanding of C. calothyrsus and G. sepium combustion for broader utilization. [ABSTRACT FROM AUTHOR]