Experimental Investigation of In-situ Biodiesel Production from Castor Seeds (Ricinus communis) Using Combination of Microwave and Ultrasound Intensification

Abstract

The current research work aims to develop novel substitute technique to produce non-edible fatty acid-based biodiesel fuel via the amalgamation of in-situ and process intensification (PI) technique (combination of microwave and ultrasound) with an objective to develop environmental friendly and industrially viable economic process. Ground castor seeds with methanol as solvent have been used in the presence of homogeneous catalyst (KOH) for transesterification reaction. Response surface methodology using central composite design (CCD) was adopted for design of experiments and to analyze the effect of factors (oil/methanol molar ratio, catalyst concentration, reaction temperature, and reaction time) on biodiesel yield. Maximum yield of 44.88 (±0.37) % was obtained under favorable process conditions of: Oil/methanol molar ratio (1:350), catalyst amount (1.74%, w/w), reaction temperature (43 °C), and reaction time (30 min). Regression equation has been developed for the model having a coefficient of determination (R2), and adjusted coefficient of determination equal to 0.9737 and 0.9507, respectively. Thermo-physical fuel properties of castor oil methyl esters (COME) were estimated and compared with ASTM and DIN standards.