Phase Equilibrium and Emulsion Stability on Ethyl Biodiesel Production

Liquid-liquid equilibrium data was measured for ethyl soybean oil biodiesel + glycerol + ethanol ternary system at 300.15 K and compared with data obtained from literature. Thermodynamic model UNIQUAC was used to correlate experimental data at 300.15, 323.15 and 343.15 K. Results show that the model was capable to correlate experimental liquid-liquid equilibrium behavior for the system studied. Two systems were considered in order to investigate emulsion stability. The first one is composed by all the transesterification reaction products before and after glycerol enriched phase separation. It can be observed that remove glycerol enriched phase after the reaction avoid the formation of stable emulsion in the presence of water. The second system contains only purified biodiesel with 5, 10 and 20 % (v/v) of water. The emulsions stability decrease with an increase on water content.