Process optimization of KOH catalyzed biodiesel production from crude sunflower-mahua oil

Abstract

The aim of the present work is to optimize process parameters to maximize biodiesel conversion from equal proportion of mixed crude sunflower-mahua oil (CSMO) through sequential esterification-transesterification reaction using KOH as catalyst. In this study, free fatty acid (FFA) was analyzed in mixed CSMO and found to be 9.8%. So, esterification was performed using sulfuric acid as catalyst to minimize the FFA. When FFA reached 3.5% (w/w), transesterification was performed for maximum biodiesel conversion through methanolysis. Plackett–Burman design (PBD) was used to screen the significant factors to maximize biodiesel production. Then, response surface methodology (RSM) based Box–Behnken design (BBD) was employed to develop a model relating independent and dependent process parameters. Finally, generalized reduced gradient (GRG) was performed to find optimal solution for biodiesel production. The optimization results revealed that the maximum FFA conversion of 93.34% was achieved at FFA of 3.52% (w/w), molar ratio of alcohol to oil of 8.61, mass ratio of catalyst to oil of 1.45%, reaction time of 23.5 h and reaction temperature of 63.9 °C, and the results were within ±1.4%. Thus, mixed CSMO could be utilized as prospective feedstock for biodiesel production.

Keywords:

• Mixed crude sunflower-mahua oil
• biodiesel
• esterification
• transesterification
• optimization

Acknowledgement

The authors would like to thank the managements of Vels Institute of Science, Technology & Advanced Studies, Chennai and Kumaraguru College of Technology, Coimbatore, India for the kind support and continuous cooperation for carrying out research.

Disclosure statement

No potential competing interest was reported by the authors.