DETERMINATION OF KINETIC PARAMETERS FOR TRANSESTERIFICATION REACTION OF PALM KERNEL OIL TO PRODUCE FATTY ACID ETHYL ESTER

This study investigated the kinetic parameters and optimization of biodiesel production from palm kernel oil (PKO) via base-catalyzed transesterification with ethanol. The research addressed the challenge of high free fatty acid content in crude PKO through acid-catalyzed esterification pretreatment, reducing the acid value from 13.0 mg KOH/g to below 0.75 mg KOH/g. A Box-Behnken Design was employed to optimize three critical process variables: reaction temperature (45-65°C), KOH catalyst loading (0.75-1.50 wt%), and ethanol-to-oil molar ratio (6:1-9:1). Seventeen experimental runs achieved biodiesel yields ranging from 78.78% to 99.58%, with the highest yield obtained at 55°C, 0.75 wt% catalyst, and 9:1 ethanol ratio. Kinetic analysis revealed that the transesterification followed pseudo-first-order kinetics with respect to triglyceride concentration, with rate constants ranging from 0.00297 min⁻¹ at 45°C to 0.02329 min⁻¹ at 55°C. The activation energy was determined to be 21.72 kJ/mol through Arrhenius analysis, indicating a low energy barrier favorable for industrial applications. Statistical analysis via ANOVA confirmed that catalyst loading (F=38.48, p=0.0004) and temperature (F=21.21, p=0.0025) were the most significant factors affecting yield, while the interaction between catalyst and ethanol ratio was also significant (F=11.09, p=0.0126). The quadratic model showed excellent fit with R²=0.9228 and adequate precision of 11.57. Numerical optimization identified optimal conditions as 47.98°C, 0.937 wt% KOH, and 7.92:1 ethanol ratio, with predicted yield of 97.91% and desirability of 1.000. Fuel property analysis revealed that the produced fatty acid ethyl esters met international biodiesel standards, with density ranging from 816-868 kg/m³ and kinematic viscosity of 4.00-7.68 mm²/s at 40°C. The study demonstrates that PKO is a viable feedstock for biodiesel production when properly pretreated, and provides fundamental kinetic data essential for industrial scale-up and reactor design.