A new purification methodology was developed to solve the
problems of extensive soap formation during ethyl ester production.
The key step is a first neutral washing. This step is followed
by a second extraction carried out with water saturated with
CO2, which is less corrosive than other mineral acids. The amount
of ethyl esters obtained using sodium methoxide dissolved in
methanol as catalyst is approximately 104% relative to the oil fed
to the system. This maximum limit was obtained combining the
transesterification with the esterification of the fatty acid recovered
from the glycerine and washing water streams.