Utilization of Agro-waste and Non-conventional Eruca sativa Seed Oil for Getting Optimized Process to Acquire Better Yield of Biodiesel by Using Response Surface Methodology (RSM)

Abstract

The Response Surface Methodology (RSM) based on Central Composite Rotatable Design (CCRD), was used to evaluate four trans-esterification reaction parameters i.e. reaction temperature, catalyst concentration, reaction time and methanol-to-oil molar ratio in order to obtain high and better yield. A 24 full factorial CCRD was applied, using four different variables at five levels; each parameter leads to 30 experiments to yield Eruca sativa oil-methyl esters (EOMEs). The molar ratio of methanol to oil and catalyst concentration were the most significant (P < 0.5) factors affecting the yield of EOMEs. A linear relationship was recorded between observed and predicted values (R2 = 0.97). Using multiple regression analysis, a quadratic polynomial equation was recognized for methyl ester yield (MEY). The quadratic terms of molar ratio and catalyst concentration showed a significant impact on yield. The interaction terms of molar ratio and catalyst concentration with reaction time revealed positive influence on MEY (P < 0.05). The optimal reaction conditions for transesterification of oils were catalyst concentration of 0.8%, reaction temperature 65 °C, CH3OH to oil ratio of 6:1 and reaction time 120 min leading to production of 95.88% Eruca oil MEY. The RSM was found to be a suitable technique for optimizing transesterification process, and manufactured fuel properties were within the ranges of EN 14214 and ASTM D6751 standards.