Thermogravimetric analyses (TGA) of three oil palm biomass pyrolysis: Kinetics and reaction mechanisms

Abstract Oil palm biomass generated from the plantation site (i.e., oil palm trunk (OPT) and oil palm frond (OPF)) are an attractive source for pyrolysis given their abundant availability. Despite this potential, there is no comprehensive study on the pyrolysis of OPT and OPF. In this work, the pyrolysis of OPT, OPF, and PKS are compared and analysed by thermogravimetric analysis (TGA). The kinetics and reaction mechanisms of these biomass during pyrolysis were determined using Kissinger-Akahira-Sunose (KAS) model-free method and Šesták-Berggren function. Pyrolysis of the three oil palm biomass is complex and exhibits different thermal behaviours and strong overlapping reaction between the pseudo-components, which can be attributed to their different constituents. The apparent activation energy of OPT, OPF, and PKS are 17.83-116.58, -45.36-225.60, and 56.50-90.42 kJ mol-1. The variation in the apparent activation energy indicates that pyrolysis of the three oil palm biomass involves multiple reaction mechanisms. Thermal decomposition of the pseudo-hemicellulose and pseudo-cellulose in the three oil palm biomass are co-controlled by two reaction mechanisms, i.e., phase boundary reaction and nucleation, with phase boundary reaction as the dominant mechanism.