The main purpose of bleaching is to remove coloring matters by absorption to obtain finished product with the desired color, on the other hand, for conventional refining, bleaching serves also to eliminate traces of soap before oil is passed to the final stage of deodorization.
The degummed/neutralised oil is first heated to desired temperature and then bleaching earth is added in adequate quantity controlled by PLC into the OILTEK Oil – Earth mixer under vacuum.
This mixture of oil and earth is then pumped to OILTEK Bleacher where it is agitated by open sparge steam and uniform bleaching takes place.
This is then transferred to Pressure leaf filters where the spent earth ( Cake) is separated and filtered oil again by passing it through polish filters.
The salient features of the process are as follows:
Uniform holding time of the oil-earth mixture in the bleacher
Oil filtration in hermetic leaf filters that requires no maintenance.
Savings of both labor and floor space, as well as in a lower bleaching earth consumption to obtain the same bleaching result.
Accurate and convenient metering of oil and earth for obtaining quickly oil of the desired color.
Filtered oil is kept under vacuum during whole process.
The bleacher is totally maintenance free as there are no mechanical agitators.
Oil content in spent earth (cake) not exceeding 24%.