Progressive Conversion Model Applied to the Physical Activation of Activated Carbon from Palm Kernel Shells at the...

Palm kernel shells, an abundant agro-industrial residue in countries like Ecuador, can be valorized through their conversion into activated carbon for industrial applications. This study investigates the physical activation of carbonized palm kernel shells using both a Nichols furnace at the pilot scale and a rotary kiln at the industrial scale. The progressive conversion model was used to explain how the activation process works and to calculate the reaction rate constants for CO₂ (kr_CO2) and H₂O (kr_H2O). The experimental results demonstrated that activation in an H₂O-rich atmosphere significantly enhanced porosity development and iodine index compared to CO₂ alone. Additionally, the study confirmed that activation kinetics are primarily controlled by the chemical reaction rather than mass transport limitations, as indicated by the negligible effect of particle size on gasification rates. At 850 °C, the reaction rate constants were calculated to be kr_CO2 = 0.75 (mol·cm^-3·s)^-1 and kr_H2O = 8.91 (mol·cm^-3·s)^-1. The model's predictions closely matched the experimental data, validating its applicability for process optimization at both the pilot and industrial scales. These findings provide valuable insights for improving the efficiency of activated carbon production from palm kernel shells in large-scale operations.