Optimization of Process Variables in the Biodiesel Production from Lophira lanceolata Seed Oil

Abstract

Box-Behnken response surface methodology was employed to optimize the process variables in alkalinecatalysed transesterification of Lophira lanceolata seed oil into biodiesel following initial acid-catalysed esterification. The model equation obtained from regression analysis adequately expressed the relationship between the biodiesel yield and the process variables with R² of 96.05%.The optimization result suggested the best combination of the process variables for optimum biodiesel yield of 85.0% are: reaction temperature (50⁰C); reaction time (120min); amount of methanol (6 cm³/g oil) and catalyst concentration (0.30 mol/dm^-3). Validation yield of 83% compares favorably with the predicted value, showing model reliability in describing the transesterification process. Results of GC-MS analysis of the biodiesel revealed it mainly consists of methyl esters of octadecenoic acid (69.5%), palmitic acid (9.4%) and hexacosanoic acid (5.6%). The biodiesel was very fluid 2.70±0.12 mm/s² with most of it fuel properties in conformity with ASTM standards making it suitable as fuel for diesel engines.

Keywords: Optimization, Lophira lanceolata, transesterification, Biodiesel, Behnken design.