Co-Pyrolysis of Oil Palm Mesocarp Fiber and Bituminous Coal Blends via Thermogravimetric Analysis

This study investigates the pyrolysis and co-pyrolysis behavior of oil palm mesocarp fiber (MF) bituminous coal fines (CF) from Ankpa in Nigeria in a thermogravimetric analyzer in nitrogen environment (100 mL/min). Pyrolysis of each feedstock and their blends (MF:CF%: 100:0%, 75:25%, 50:50%, 25:75%, 0:100%) was carried out with temperatures ranging from ambient to 900°C. This was done at heating rates of 5, 10, and 15°C/min. Each feedstock showed two distinct behaviors during the active pyrolysis stages and this trend was maintained in their blends. Increasing the proportion of CF reduced the peak mass loss rate and increased the corresponding peak temperature across all blends and heating rates. Blending with ≥25% MF lowered the peak devolatilization temperature and raised the maximum mass loss rate, indicating a catalytic effect on coal pyrolysis. Higher heating rates shifted decomposition to higher temperatures while intensifying mass loss rates. Residual mass decreased slightly with increasing heating rate but rose with higher CF content. The activation energy for CF was substantially higher than that of MF for all heating rates. In addition, the activation energy for the second-stage reactions of the blends was higher than that of MF but lower than that of CF for all heating rates. The increase in the values of activation energy as the percentage of MF reduces in the blend suggests a progressive reduction in the reactivity of the solid fuel mix. Also, blending with ≥25% MF led to a marked reduction in the activation energy relative to pure CF, affirming the catalytic effect of MF on Ankpa bituminous coal in co-pyrolysis.