Optimization and Kinetic Studies on Biodiesel Production from Kusum (<i>Schleichera triguga</i>) Oil Using Response Surface Methodology

Abstract

In the present study, the low-cost non-edible kusum (Schleichera triguga) oil with a substantial amount of free fatty acid (FFA) was utilized for biodiesel synthesis. In pretreatment step, FFA was reduced by the acid catalyzed esterification method. Then, response surface method (RSM) in conjunction with centre composite design (CCD) containing 30 experimental runs were statistically employed for process optimization and kinetic study for the base catalyzed transesterification process. A statistical model predicted highest fatty acid methyl ester (FAME) yield of 97.37% at the optimal values of process parameters as follows: sodium methoxide concentration 0.9 wt% of oil, Methanol to oil molar ratio 9:1, temperature 58.9℃ and reaction time 58.5 min. Using these optimal parameters under experimental conditions in three independent replicates an actual FAME content of 98.14% was obtained which was in reasonable agreement with predicted one. The developed kinetic model suggested a 1.8th order reaction with activation energy of 31.42 kcal mol–1 and frequency factor of 5.53×1019 L mol–1min–1. Furthermore, Important fuel properties of kusum oil biodiesel (KOB) was compared with ASTM 6751 and DIN EN 14214. The viscosity was found to be 5.34 Cst at 40°C and the flash point was 152°C.