Characterization, Kinetics, and Thermodynamics Analysis of Palm Kernel Oil Extraction

Abstract

The inefficiency frequently encountered in oil extractors can be attributed to the insufficient availability of kinetics and thermodynamic data during the design phase. This study examined the kinetics and thermodynamics involved in the extraction of oil from palm kernel seeds. The mass transfer kinetic power model and the laws of thermodynamics were applied to describe the kinetics and the thermodynamics of the oil extraction process, respectively. The physicochemical parameters of the palm kernel oil extracted were determined according to the methods recommended by the Association of Official Analytical Chemists. The results showed that a maximum oil yield of 48.56% was obtained from the dried palm kernels under optimum conditions of 70 °C, a particle size of 2.0 mm, and an extraction duration of 90 min, using 250 ml of n-hexane. The oil extraction process was found to follow second-order kinetics, whose rate constant is dependent on temperature, and the activation energy (Ea) was 54.69 kJ/mol. The thermodynamic parameters of the extraction process were an enthalpy change (ΔH) of 24.94 kJ/mol, an entropy change (ΔS) of 0.08 kJ/mol, and negative values of Gibbs’ free energy change (ΔG) at each prevailing temperature value. The results of the thermodynamic study implied that the palm kernel oil extraction process is endothermic and requires a constant supply of energy for effective and efficient extraction. Also, the physicochemical properties of the oil showed that it is edible and also suitable for use in soap production, pharmaceutical industries, and as a feedstock in the production of biodiesel.