Thermogravimetric Kinetics of Catalytic and Non-Catalytic Pyrolytic Conversion of Palm Kernel Shell with Acid-Treated Coal Bottom Ash

The catalytic and non-catalytic pyrolytic conversion kinetics of palm kernel shell (PKS) with untreated (as received) and H2SO4-treated coal bottom ash as catalyst were investigated in this study. Flynn-Wall-Ozawa (FWO) and distributed activation energy model (DAEM) isoconversional kinetic models were exploited to evaluate the kinetic parameters. The study was conducted using thermogravimetric analysis at 10, 20, 30, and 50 °C/min heating rates. The activation energy (Ea) and pre-exponential factor (A) for non-catalytic PKS decomposition for DAEM ranged from 74.39 to 217.05 kJ/mol and 4.77E+01 to 1.99E+14 s−1 at different conversions while for the untreated ash, the ranges were 103.84–402.53 kJ/mol and 7.35E+03–1.04E+29 s−1. In the decomposition with treated ash, Ea and A were 81.79–191.07 kJ/mol and 1.61E+02–1.20E+12 s−1 for 7 wt% ash and 74.41–137.35 kJ/mol and 4.91E+03–4.53E+08 s−1. Values of Ea and A obtained for FWO followed the same pattern and are in close agreement with that obtained using DAEM. The use of 10 wt% acid-treated ash reduced the activation energy compared with the non-catalytic process by about 33.05% while the untreated ash increased the activation energy. The kinetic parameters were determined satisfactorily using the first-order reaction mechanism.