Biodiesel purification method

1- PROCESS FOR PURIFICATION OF BIODIESEL, obtained from the transesterification of castor seed oil in the presence of ethanol and an alkaline catalyst characterised by separating the glycerine formed during the transesterification reaction, in a drastically reduced time, comprising the steps of:

• partially removing by evaporation the excess of ethanol present in the mixture of esters which is composed of 60% to 80% of alkydic esters, 5% to 15% of glycerine, and 15% to 30% of ethanol, using a heating bath to keep the mixture warm;
• adding to the mixture resulting from the evaporation of the ethanol approximately 0.7% of water and 2% to 5% of n-hexane, whilst homogenising it;
• transferring the homogenised mixture to a decanting vessel provided with electrodes, promoting contact between said mixture and the glycerine stock existing in the decanting vessel, in a proportion of 10:1 to 5:1 by volume;
• applying an alternating electrical current, provided by the operation of high voltage converters, preferably in the range 1 to 5 KV, in order to promote the electrostatic separation of the glycerine.