The crude vegetable oils such as Soyabean Oil, Sunflower Oil, Mustard Oil, Rice Bran Oil from expeller or Solvent Extraction Plant in addition to Glycerides and fatty acids, contains other impurities which may be removed prior to neutralization . These impurities may be grouped as follows :-
- Solid Impurities
- Mucilaginous material, phosphates peroxides etc.
- Volatile Impurities (Water solvent ether etc.)
It is therefore important to remove these impurities prior to purification/refining. If these impurities are not filtered out before refining, following inconveniences are often encountered during the lengthy refining cycle :
- Formation of, difficult to process sludge in storage tanks
- Higher oil losses during the neutralization stage because fines act as emulsifying agent
- Slowing down of the processing cycle in all cases where neutralization is carried out in centrifugal separators because these are unable to expel the solid materials which rapidly clog the bowls requiring the operation to be stopped for cleaning.
As can be easily understood, the solid foreign matter should be separated prior to storage and refining of oil. This operation is technically referred to as ‘Desliming ‘ and though it has world wide acknowledgement as essential step to ensure good keeping properties of the oil. It was hardly ever done because until recently simple, efficient and economical was not available.
For this filtration Horizontal Pressure Leaf Filter is found most simple and economical filtration equipment. SHARPLEX have Carried out extensive trials with different crude oils. It is observed that with suitable pre-coat material it is very easy to filter out all impurities with Horizontal Pressure Leaf Filter. Moreover SHARPLEX Horizontal Pressure Leaf Filter are automatic and cake after filtration can be dried by compressed air and dislodged by pneumatic vibrator.
Another advantage is you do not require filter cloth at all. Operation is easy allows visual inspection of the filter cake discharge.
For crude oil filtration the filter screen has to be carefully selected in respect to the quality of solids present and type of crude oil to be filtered. Our expertise in this application enables us to specify the right type of screen for various oils to be filtered. The actual filter cycle comprises of following steps :
- Pre – coating
- Re-circulation till clarity
- Filtration
- Draining
- Drying the solids
- Dislodging of cake
The filter cake is subsequently returned to the solvent extraction plant or expellers in order to remove oil as much as possible which is retained in the filter cake.
Conclusion
- Filtration of crude oil to remove all solids material makes downstream processing easier.
- The use of totally enclosed, hermetic Horizontal Pressure Leaf Filter will reduce labour and improve house keeping
- Lower neutralization losses gives more yield of oil.
- Lower consumption of bleaching earth during bleaching operation.
- Oil can be stored for a long time thus observing high standards of keeping quality.
- Incase of lecithin manufacturing good quality food grade lecithin can be obtained.
