The acid esterification unit is designed to convert oleins coming from glycerine purification (unit 6166P) and/or fatty acids/oil from battery limit to methylesters according to the following reaction:

R-CO-OH + CH3OH   CH3-O-CO-R + H2O
Fatty Acid    Methanol   Methylester   Water

The esterification reaction is accomplished in continuous using a tubular reactor (6191A1) operating at 110-130 °C and 8-10 barg.

The catalyst of the reaction is sulphuric acid (H2SO4), supplied as 98% aqueous solution.


The Desmet Ballestra Acid Esterification Unit allows to totally recovering the oleins produced as by-product of the upstream process unit converting them into methylesters.

The main advantage of this technology is the economical profit resulting from the conversion of low quality by-product (oleins) into a higher profitable product (methylester) to be blended with oil fed to transterification process.