Transesterificação do óleo de gergelim em um processo batelada usando etanol supercrítico ; Transesterification of sesame oil in a batch process using supercritical ethanol

With the increase in the environmental problems generated using fossil fuels, the search for more renewable and less harmful fuels alternatives have increased, thereby biodiesel rise as a biodegradable option originated from natural sources. In Brazil, soybean oil is the most used feedstock in biodiesel production, however it is necessary to search for other oilseeds to diversify a production, so the sesame oil appears as a likely raw material. Sesame seeds have a high oil content and it is suitable for a warmer and drier climate. The main way to produce biodiesel is the catalytic transesterification, nevertheless, with the use of alcohol under supercritical conditions it is not necessary to use catalysts making the method simpler. In this work it was proposed the use of sesame oil as feedstock for the transesterification reaction with ethyl alcohol under supercritical conditions. The experiments were conducted in a batch-type reactor with a total volume of 300 mL, varying the temperature from 260-290 ℃, reaction time from 7.5-30 minutes and the oil to ethanol molar ratio from 1:36-1:48. Physical properties of the sesame oil like acidity index, free fatty acid content, kinematic viscosity, density and water content were also analyzed. In addition, a statistical study of the experimental data was carried out with the influence of the variables studied on the yield of ethyl esters. In the end, analysis of oil properties showed that sesame oil has great potential as feedstock for biodiesel production. The highest FAEE yield found was 56.62% at the temperature of 290 ℃, at reaction time of 30 minutes and oil to ethanol molar ratio of 1:48. It was observed that increasing temperature has increased yield without thermal degradation of the esters. The statistical study showed that the effects of temperature, time and the interaction between temperature and molar ratio were significant. ; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) ; Com o aumento dos problemas ambientais gerados pelo uso de ...