Activation Energy Determination of Palm Kernel Shell Thermochemical Conversion in the Devolatilization Zone Using Volatile State Vyazovkin Isoconversional Method

ABSTRACT

The involvement of ash amount ( m _f ) in biomass pyrolysis kinetic calculations in the devolatilization zone leads to the temperature deviation from the specified heating rate in the isoconversional system. Several methods applicable to temperature variations have been developed to account for the impact of such temperature deviations. This study combines devolatilization and isoconversional principles to evaluate the activation energy of palm kernel shell pyrolysis using volatile state Vyazovkin isoconversional method. The calculations were performed by observing the conversion (α) and volatile release yield (α′) in the devolatilization zone. Verification was then conducted on the results of the temperature integral p(x) using both linear and non‐linear methods. Based on these findings, the activation energy using the isoconversional method has been determined according to the DTG curve trajectory. Following the results, the activation energy of moisture release as well as hemicellulose, cellulose, and lignin decomposition at each temperature using volatile state (Eαʹ) is 24.09–30.79 kJ mol ⁻¹ (376.31–396.88 K), 125.22–153.50 kJ mol ⁻¹ (504.34–570.64 K), 152.19–170.45 kJ mol ⁻¹ (573.51–631.60 K), and 24.35–103.34 kJ mol ⁻¹ (641.23–652.89 K). In the meantime, using solid state (Eα) is acquired at 22.13–25.49 kJ mol ⁻¹ (377.59–393.25 K), 138.22–177.26 kJ mol ⁻¹ (524.49–570.24 K), 185.56–212.02 kJ mol ⁻¹ (574.60–631.99 K), and 25.26–279.05 kJ mol ⁻¹ (642.18–714.02 K). This method is expected to address certain inconsistencies in the current determination of activation energy, specifically by involving linearization and solid‐state approach.