Page 28 - TECHNICAL SPECIFICATION FOR PALM OIL REFINING_rev.1 - Copy_Float

OFFER NO. KMIPL/P16E0097R7
100 TPD PHYSICAL REFINERY AND FRACTIONATION
Page No. 28/69

B. Process Description – Dry Fractionation

Fractionation is purest modification process as it is basically a reversible

physical separation process. The Fractionation of the oils or fats is a thermo
mechanical separation process where high & low melting triglycerides are

separated by partial crystallization, followed by filtration.

The dry Fractionation is the most widely used process & it is employed to

separate solid & liquid triglycerides from numerous sources of fat. The key point

in dry fractionation is the selectivity of crystallization which is determined by
the thermal condition & more specifically by the cooling profile. The triglycerides

are characterized by a complex melting & crystallization behavior due to the

existence of multiple crystalline forms (α, β’, β) each from having its specific
physical properties.

Crystallization is complicated by the inter solubility of the triglycerides. Different

components may combine to form mixed crystals, according to nature of the

crystal form. The triglycerides found in the palm oil have different melting
points. At certain temperatures, the lower melting temperature triglycerides will

stay liquid while the higher melting temperature triglycerides will crystallize into

solid, separating the oils into both liquid & solid fractions.

The crystals are separated by filtration. To obtain good separation, the Stearine
crystals must indeed be firm & of uniform spherical size which is a condition

found when they are mainly in the β form. To reach this state, the oil is initially

heated to a temperature above the final melting point of the oil, in order to fully
destroy the crystals that are present in the oil phase.