Fractionation

Dry Fractionation process

Dry Fractionation is a physical process without any chemical change to the incoming oil. In opposition to other fractionation processes: Solvent Fractionation and Detergent Fractionation there is no use of chemical additives, no yield loss (no effluent) and no contamination.

The quality of fractionation plant lies in its ability to separate in selective way the different triglycerides, so we reach targeted composition of olein and stearin.Unfortunately the interaction among various component of palm oil (over 40 glycerides), design of the crystallizer (mechanical and thermodynamic), the process control, as well as the filtration influence drastically this operation.

The process can be described as follow: the hot oil, with fully melted di- and triglycerides we cool down until reaching super-saturation . When this one is sufficient, the super-cooled oil enters the phase of nucleation ( creation of crystal germs ), followed by crystals growing phase. One may think that the high melting point (MP) triglycerides (TAG) will crystallize first as nuclei, than the lower melting point TAG will join and so on, until we create slurry of so called “stearin” crystals, suspended in liquid “olein” . But is far from that simple.

We face very complex exothermic, polymorphic crystallisation process, where the dynamic of crystallisation is not fully related to the melting points. Furthermore, the inter-solubility of various triglycerides affects the selectivity of the crystals build-up. The temperature control of oil and water (but not only !) has a critical influence during nucleation stage, as well as during crystals growth.

Due to all these factors that make this process so fragile and sensitive, we can understand that the term of “art of crystallisation” is well justified.

The KCS dry fractionation plant

This know-how is in big part the result of some 12 years of project engineering by Fractionnement Tirtiaux S.A. (Belgium). Elaborating fractionation plants for palm oil, butter, fish oil, with various types of crystallizers and filters, together with R&D department, has given us very complete view on this complex technology.

Main sections of KCS dry fractionation modern plant:

• Active Loading – transfers the oil from the storage farm , or buffer tank to crystallizer. During this operation crystallized oil melts, but also we “anticipate” nucleation stage.
• Crystallizer – cools the oil precisely to the recipe in order to achieve selective crystallisation and optimal growth of crystals during holding time until the olein has reached targeted quality.
• Membrane filter – physical separation between “ olein ” and “ stearin ”trough filter cloths, installed on various types of filter plates
• Process control – MCC and PLC control panels with highly developed computer SCADA system to supervise and control the plant operation.

Whole installation is equipped with necessary water and oil pumps, buffer tanks and additional utility equipment (cooling towers, chillers, air compressors, etc).