Biodiesel has attracted growing attention worldwide in recent years. The production of biodiesel from biomass involves separation and purification steps. The method generally used, the aqueous washing, has major disadvantages such as the generation of wastewater and forming emulsions. The objective of present work is to investigate the biodiesel purification using carbon dioxide, which in supercritical conditions has properties capable of separating glycerol phase of esterified phase (biodiesel), providing higher quality products and less waste. In this study, two simulations were used for analysis and investigation of purification of crude palm oil biodiesel. Both configurations conventionally designed the project process via ethylic route by basic catalysis to the reaction step. The "case 1" used a fractional distillation column for separating excess ethanol and a liquid-liquid column extraction using water as solvent for the separation of glycerol. The "case 2" applied a fractionating column in countercurrent, used for the glycerol separation step, carbon dioxide as supercritical solvent and for separating excess of ethanol, a flash vessel in the final purification of biodiesel. The simulator employed was Aspen HYSYS V8.4 that used binary parameters, adjusted with the equations of state of Soave-Redlich-Kwong (SRK) and Redlich-Kwong-Aspen (RK-ASPEN) to study systems, performed the simulations appropriately. The supercritical CO2 proved to be efficient in the separation of glycerol, given that biodiesel produced with this purification technology met the ANP main standards rules.
|
