Optimization and Reaction Kinetics of the Production of Biodiesel From Castor Oil

Ricinus communis, commonly known as the castor plant, has been cultivated for millennia as a source of oil for lamps and other applications. The seeds of the castor plant contain 35% to 55% oil. The major fatty acid component of castor oil is ricinoleic acid, which comprises 90% of the fatty acids present in castor oil. Ricinoleic acid is a monounsaturated, 18-carbon fatty acid with a hydroxyl functional group at C-12. This hydroxyl group causes castor oil to be highly polar, simplifying the mixing of the oil with methanol for the biodiesel reaction. Castor oil is more viscous than typical oils, which poses problems in the resulting biodiesel. A study of the esterification reaction kinetics of converting the castor oil into biodiesel was performed to determine reaction kinetics. This information can be used to engineer a biodiesel production facility with castor oil as a feedstock. Factors considered in the kinetics study included reaction temperature, catalyst concentration, ratio of methanol to oil, and reaction time. The resulting biodiesel was tested for compliance with appropriate ASTM standards. Production of biodiesel from castor oil would provide two benefits: (1) a biodiesel feedstock oil that does not diminish the food supply, and (2) reduce the US dependency on foreign oil by providing a domestic alternative to petroleum diesel.