- 1Sourcing Custom Palm Fractions→
- 2Step 1: Homogenization & Thermal Conditioning→
- 3Step 2: Controlled Cooling & Crystallization→
- 4Step 3: Membrane Filtration & Squeezing→
- 5Logistics & Bulk Sourcing of Palm Fractions→
- 6Sourcing Sustainable & Certified Fractions→
- 7Fraction Properties Comparison→
- 8Frequently Asked Questions (FAQ)→
Dry fractionation is the core physical process used to separate refined palm oil into its liquid (olein) and solid (stearin) components. Unlike seed oils that remain liquid at room temperature, palm oil contains a balanced ratio of saturated and unsaturated fatty acids, making it semi-solid. By utilizing controlled thermal crystallization and high-pressure membrane filtration without the use of chemical solvents, dry fractionation allows refiners to produce customized fractions for frying, baking, and industrial applications. This technical guide explores the engineering stages, crystallization physics, and quality metrics of dry fractionation.
Sourcing Custom Palm Fractions
Because palm oil naturally crystallizes over a wide temperature range, refiners must fractionate the oil to meet specific customer requirements. Importers in cold climates require liquid olein fractions that remain clear, whereas margarine manufacturers require solid stearin fractions to provide structural plasticity. Working with an established global bulk palm oil supplier ensures access to a full range of customized melting point fractions.
📚 Upstream Milling Link
Fractionation begins with high-quality crude oil. To understand how palm fruits are harvested and pressed to minimize acidity before refining, read our guide on the palm oil milling process.
Step 1: Homogenization & Thermal Conditioning
The first step in dry fractionation is thermal homogenization. Refined, bleached, and deodorized (RBD) palm oil is heated to 70°C to 75°C and held for several hours. This ensures that any pre-existing fat crystal networks are completely melted, creating a uniform isotropic liquid. Failing to homogenize the oil leads to uncontrolled crystal growth during the cooling phase, reducing separation efficiency.
Refining quality is also heavily dependent on raw material freshness. Refining plants source high-quality feedstocks from a registered crude palm oil supplier to minimize processing loss.
Step 2: Controlled Cooling & Crystallization
The homogenized oil is pumped into large crystallization vessels equipped with cooling jackets and slow-speed agitators. The cooling program is carefully managed according to a pre-defined temperature profile, slowly reducing the oil temperature from 70°C to approximately 18°C–22°C over a 12 to 24-hour cycle.
During this slow cooling, high-melting-point saturated triglycerides (such as tripalmitin) begin to nucleate and grow into solid crystals, while low-melting-point unsaturated triglycerides remain liquid. The agitator speed is kept very low (typically 5 to 10 rpm) to prevent breaking the fragile crystal aggregates. Refinement details can be reviewed with a specialized RBD palm olein supplier.
Step 3: Membrane Filtration & Squeezing
Once crystallization is complete, the crystal slurry is pumped into a high-pressure membrane chamber filter press. The filter press consists of multiple vertical plates lined with filter cloths and flexible membranes.
- Filtration: The slurry is pumped into the press chambers at low pressure. The liquid olein passes through the filter cloths and is collected, while the solid stearin crystals are retained in the chambers, forming a filter cake.
- Squeezing: High-pressure water or air (6.0 to 15.0 bar) is inflated behind the membranes, squeezing the stearin filter cakes. This expels remaining entrained liquid olein from the crystals, maximizing separation yields.
- Discharge: The filter plates open, and the solid stearin cakes drop into a melting tank below, heated to 60°C for storage and shipping.
Logistics & Bulk Sourcing of Palm Fractions
Transporting different palm oil fractions requires careful temperature management during transit. Saturated stearin fractions must be kept warm to prevent solidifying inside pipes and tanks, whereas liquid olein must be protected from cold crystallization. Importers should partner with a reliable bulk palm oil supplier to coordinate flexitanks equipped with steam heating pads or ISO tanks.
Additionally, modern logistics planning must account for seasonality and geographic temperature profiles. Refiners adjust cloud point settings based on whether they are exporting to a Malaysia palm oil supplier or a Western distributor.
Sourcing Sustainable & Certified Fractions
With environmental regulations tightening in Europe and North America, buyers must verify that their palm olein and stearin fractions are sustainably produced. Sourcing from a certified sustainable palm oil supplier ensures compliance with the Roundtable on Sustainable Palm Oil (RSPO) and EUDR deforestation due diligence rules.
Importers should select specific cloud point grades based on regional climates to prevent crystallization in transit. Compare CP8 and CP10 specifications at our refined palm oil supplier comparison page.
Fraction Properties Comparison
The table below summarizes the typical chemical and physical differences between palm olein and palm stearin fractions obtained from dry fractionation:
| Specification Parameter | Liquid Fraction (Palm Olein) | Solid Fraction (Palm Stearin) |
|---|---|---|
| Yield from RBD Palm Oil | 70% – 80% | 20% – 30% |
| Iodine Value (IV) | Min 56.0 (typically 56.0 – 60.0) | Max 48.0 (typically 30.0 – 40.0) |
| Slip Melting Point | 20°C – 24°C | 48°C – 56°C |
| Saturated Fatty Acids | 40% – 45% (Lower Saturation) | 56% – 65% (High Saturation) |
| Primary Applications | Frying oil, household cooking oil | Shortening, margarine, soap noodles |
Frequently Asked Questions (FAQ)
Does dry fractionation involve chemical solvents?
No. Dry fractionation is a purely physical process that relies on controlled cooling to crystallize the solid fats followed by high-pressure mechanical filtration. No chemical solvents or additives are used, ensuring a clean, food-grade final product.
What is double fractionation and what does it produce?
Double fractionation involves fractionating liquid palm olein a second time under lower temperatures (typically 12°C–15°C). This removes remaining high-melting-point stearin crystals, producing a super olein fraction (such as CP6) with min 60.0 IV that remains clear in colder climates.
Why is slip melting point critical for palm stearin contracts?
The slip melting point determines the hardness and plasticity of the stearin fraction. Margarine and shortening manufacturers specify precise slip melting point ranges to ensure their final spreads maintain correct consistency under regional temperatures.
Request Bulk RBD Palm Olein FOB / CIF Price Quotes
PalmAzia exports premium Malaysian RBD Palm Olein CP8 and CP10 in 21.5 MT Flexitanks, ISO Tanks, Drums, and Bottled Formats from Port Klang and Pasir Gudang.