The crude methylester coming from transesterification (unit 6163T) contains a significant amount of methanol and glycerine together with sodium methylate, soaps and other contaminants as residue.
While methylester and glycerine are practically insoluble forming a clear interface, methanol is soluble in both phases and therefore it causes a mixed layer of glycerine in the methylester phase and vice versa.
The glycerine separation unit is designed to minimize methanol content in the crude methylester in order to separate as more effectively the glycerine from the crude product.
To achieve this goal, the crude methylester is heated and flashed under vacuum and then settled in order to allow the glycerine removal. The evaporated methanol is then recovered by condensation.
The Desmet Ballestra Glycerine Separation Unit is essential to maximize the glycerine removal from crude methylester in order to ease the downstream purification of the product.