Studies on Esterification Optimization of High FFA Content Pongamia Oil Using Box–Behnken Design

Biodiesel is one of the several alternative fuels, which can be used without any modification in diesel engine. The nonedible Pongamia pinnata oil (PPO) possessing high free fatty acid (FFA) content has been investigated as a potential source of biodiesel production in the present study owing to its abundant availability in India. A two-step biodiesel production method can be employed via acid esterification of free fatty acids followed by base-catalyzed transesterification reaction. In the present study, the FFA of PPO is reduced to less than 1.5% and the process parameters of the esterification reaction have been investigated and optimized using Box–Behnken design (BBD) of response surface methodology (RSM) in lieu of Trial and Error method. The parametric effects of methanol to oil molar ratio, the catalyst concentration, and reaction time were investigated on acid value and yield %. The optimum conditions obtained from regression models were found to be 6.58:1 methanol to oil ratio, 2 wt% catalyst loading, and 2 h of time.