KINETIC MODEL OF ALGAL BIODIESEL PRODUCTION UNDER SUPERCRITICAL METHANOLYSIS

A model for the supercritical trans-esterification reaction of algae is developed to study the effect of the operating parameters on the process kinetics. A well-mixed batch reactor equation was used to express the lab scale reactor. The model is based on experimental data described in a previous study. The experimental work were designed to study the effect of reaction time between 5-50 min; reaction temperatures of 423-573K, and methanol to dry algae volume/weight (vol./wt.) ratios of 12:1-40:1. The fitting of the data indicated that the reaction is a forward first order reaction in terms of triglycerides. Two parameters were introduced to consider the effect of methanol to algae ratio and reaction time. The activation energy is 9.91 kJ/mol. Excellent fitting between the experimental results and model prediction is observed. The model shows that the optimum methanol to algae ratio and reaction time were 26 and 27 min. respectively. The triglyceride at the model optimum conditions at 600K is almost completely converted to biodiesel.