Monday, May 4, 2009
9-29
Biodiesel production from castor oils: Optimization of alkaline ethanolysis and scale up
Nívea De Lima da Silva, Department of Chemical Process – School of Chemical Engineering, State University of Campinas, Cidade Universitária, Campinas, 13083970, Brazil, César B. Batistella, Chemical Engineering School, State University of Campinas - UNICAMP, Albert Einstein, 500, Campinas, , 13081-970, Brazil, M.R. Wolf Maciel, Faculty of Chemical Engineering, State University of Campinas (UNICAMP), P.O. 6066, Campinas-SP, 13081-970, Brazil, and Rubens Maciel Filho, Department of Chemical Process, School of Chemical Engineering, State University of Campinas, Cidade Universitária, SAO Paulo, Brazil.
This work presents the biodiesel production from castor oils with bioethanol in the presence of sodium ethoxide and sodium hydroxide as catalyst. The studied variables were reaction temperature, catalyst concentration, and ethanol: castor oil molar ratio. The experimental design was used in the process optimization because this methodology permitted a careful examination of the process variables. A real model that described the biodiesel conversion in terms of temperature, molar ratio ethanol/castor oil was identified. A small scale up was realized with a batch stirrer reactor and these results were compared with the magnetic agitation. A conversion of 99 %wt of ethyl ester was obtained at 30°C with 1%wt of catalyst after 30 minutes of reaction. The kinetic study of the transesterification ration was realized. The apparatus used for the experiment was a 1-L jacketed reactor, equipped with a variable speed agitator. The temperature of the reactor was controlled and maintained at 30, 40, 50, 70 °C . The reaction time was 30 minutes and samples were collected and analyzed in an HPSEC (High performance size-exclusion chromatography). The castor oil molecular weight was determined using the gas chromatography analysis and vapour pressure osmometry technique (VPO).