Optimization of biodiesel production from mixture of edible and nonedible vegetable oils

• Mixture of oils were explored as the potential feedstock for biodiesel production.
• Process optimization was done by developing response surface methodology (RSM) models.
• Biodiesel with good fuel properties was produced from mixture of above oils.
• GC and FTIR analysis of biodiesel was also done.
• Good yield of biodiesel (97%) was obtained at optimized conditions.

In the present study, optimization of biodiesel production from mixture of edible and nonedible vegetable oils with low to high free fatty acid (FFA) has been investigated. The selection of oils was based on richness of particular fatty acid in it. The combination of oils has been optimized to get suitable mixture for production of biodiesel. The mixture was analyzed in terms of physical properties and accordingly two step esterification process was applied. For optimization study, the response surface methodology(RSM) based central composite design (CCD) was used in Design of Experiments (DOE) software to optimize the various process variables such as reaction time, methanol to oil molar ratio, reaction temperature and catalyst concentration for biodiesel production . A quadratic model was created for the prediction of the Biodiesel yield. The R2 value of the model was 0.96 which indicates the satisfactory accuracy of the model. The optimum conditions were obtained as follows: reaction temperature of 43.50 °C, methanol to oil molar ratio of 8.8:1, catalyst concentration of 1.9 g/100 cc feed, reaction time of 58.4 min. At these reaction conditions, the predicted and observed biodiesel yield was 97.02% and 97.00%, respectively. These values experimentally satisfied the accuracy of the model. GC and FTIR analysis of biodiesel was also done for biodiesel characterization.