A Review on the Palm Oil Waste Thermal Degradation Analysis and Its Kinetic Triplet Study

The rising use of palm oil has increased palm oil waste. Several organisations repurpose the palm oil waste from the extraction process by altering its molecular structure through thermal degradation. This review paper aims to provide an overview of the various degradation methods (pyrolysis, torrefaction, gasification, and hydrothermal) used on palm oil waste, as well as the factors (particle size, pretreatment, and heating rate) that influence degradation and the behaviours (conversion, heating zone, activation energy, pre-exponential factor, and reaction model) that are observed during degradation. The paper also compares and contrasts the thermal degradation latest research in this field from 2018 to 2022, highlighting the advantages and disadvantages of different degradation techniques and identifying research gaps and future recommendations. The review also identified that the activation energy for degradation tends to increase with increasing heating rate and that the conversion of feedstocks to products can be improved through the pretreatment and the waste particle size optimisation. For the reaction model of palm oil waste, the first-order reaction model is often used to describe the degradation of empty fruit bunches (EFB) during pyrolysis, while the 3-dimensional (3D) diffusion (Jander) model is commonly used for oil palm shell (OPS) and the reaction order for mesocarp fibre (MF) varied between studies.