Refining of vegetable oil is
essential for the removal of impurities like gums, waxes, free fatty
acid etc from the oil to impart uniform color by removal of coloring
pigments and to get rid of unpleasant smell. Oil refining is carried out
in two processes- batch operation or continuous operation.
The equipments involve in refining are :
- Neutralizer
In neutralizer the caustic soda reacts with free fatty acids present
in the oil and forms soap stock which is separated out by
centrifugal separator. For complete removal of soap stock, oil is
washed with water. centrifugal separator separates the wash water.
- Degumming Plant
In degumming plant oils are given acidic treatment by which gums are
precipitated and separated out by centrifugal separation.
- Bleacher
For decoloring of oil, bleacher is used. Here the neutralized oil is
treated with bleaching agent for removal of coloring pigments. The
oil is mixed with bleaching earth or other bleaching agents and
heated to certain temperature and pumped to the continuous bleacher
operating under vacuum where an effective bleaching takes place.
- Deodorizer
Deodorizer is an equipment used for deodorization process. In
deodorization process the foul smell of the oil is removed. The feed
pump carries the bleached oil to the deaerator where the pretreated
oil is degassed. Oil is heated in a heat exchanger. The heated oil
is fed to a flash chamber and flows thereafter to an oil distributor
inside falling film deodoriser. The oil descends counter current to
the stripping steam in the form of very thin film and gets
completely deodorised.
