Comprehensive analysis on potential factors of ethanol in Karanja biodiesel production and its kinetic studies

Biodiesel is the potential substitute to petroleum diesel due to its renewable nature as it is derived from bio-based feedstocks. Both methanol and ethanol have been used as alcohol in transesterification reaction, but as methanol is normally derived from fossil resources, biodiesel produced cannot be termed as completely renewable. As per policies of government of India, Ethanol is being promoted as potential biofuel because it is derived from biomass feedstock. Along with its direct use as biofuel, ethanol can also be incorporated as solvent alcohol in transesterification reaction. This work is an attempt to investigate the potential of ethanol in Karanja biodiesel production by analysis of kinetics of transesterification and its comparison with methanol transesterification. The result of experimental investigation shows that maximum yield of 88.7% and 77% was obtained for methanolysis and ethanolysis respectively at reaction temperature 60 °C, 9:1 molar ratio (alcohol to oil), 1.25 wt.% catalyst loading (KOH) and reaction time of 120 min. It was observed that rate constant and activation energy was 0.007105 min−1 and 20.19 kJ/mol for methanolysis respectively whereas same for ethanolysis was 0.006294 min−1 and 23.35 kJ/mol for ethanolysis. This shows that transesterification reaction proceeds slower when ethanol is used and more energy is required. Fuel properties of ethyl ester of Karanja Oil were found to be superior as compared to corresponding methyl ester. Still it is viable option from Indian prospective because Government of India is promoting the use of ethanol as a potential source of biofuel due to its renewable nature.