Optimization of high-energy density biodiesel production from camelina sativa oil under supercritical 1-butanol conditions

Transesterification of camelina sativa oil to produce fatty acid butyl esters under supercritical 1-butanol conditions was systematically studied at alcohol to oil molar ratios of 20:1-60:1, reaction temperatures of 280-320°C, and reaction times of 20-100 min. The response surface methodology was applied to evaluate the effects of process parameters on the transesterification yield and biodiesel quality. Two mathematic models for different time ranges of 20-60 min and 30-100 min were developed and combined to predict the response over a long reaction time range. The predicted responses agree well with the experimental yields. A maximum biodiesel yield of 87.6% was obtained at a reaction time of 305°C, 1-butanol to camelina oil molar ratio of 40:1, and reaction time of 80 min. The physical properties of butyl biodiesel were evaluated and compared with those of regular diesel. The good cold temperature property (pour point of -19°C) and high calorific value (HHV of 39.97 MJ/kg) make the camelina oil butyl biodiesel an ideal liquid transportation fuel.