Comprehensive Guide to Palm Oil Refining: Key Process Parameters and Optimization Strategies

Palm oil refining is a critically intricate operation, where precision in process control ensures product quality and operational sustainability. From crude oil to consumer-grade refined oil, the refinement involves four pivotal stages: degumming, neutralization (deacidification), bleaching (decolorization), and deodorization. The nuanced management of each phase determines the final oil’s color, acidity, and odor profile, thereby directly impacting market acceptance and regulatory compliance.

1. Degumming: Eliminating Phospholipids for Stability

Degumming targets the removal of phospholipids, mucilage, and trace impurities that can accelerate oil spoilage. Maintaining a treatment temperature between 60–70°C with precise hydration levels—commonly 3–5% water content—is essential. Overhydration risks emulsification, complicating subsequent phases, while underhydration leaves residual gums causing turbidity.

The typical phospholipid content reduction from an initial 800–1200 ppm to below 10 ppm post-degumming ensures optimized neutralization efficiency. The use of automated water dosing within industrial-scale lines, such as those manufactured by the Qeé Group employing stainless steel reactors, enhances uniformity across batches and reduces operator error.

2. Deacidification (Neutralization): Reducing Free Fatty Acids (FFA)

The neutralization step involves caustic soda (NaOH) addition to react with free fatty acids, forming soaps that are subsequently separated. Controlling the NaOH concentration, typically 20–25%, and dosing at a ratio of 0.3–0.5% by oil weight ensures FFA levels drop from an initial 5–6% to less than 0.1%—a critical threshold for meeting food safety standards.

Key parameters include:

• Reaction temperature: 70–80°C
• Mixing intensity: 200–300 rpm to ensure total NaOH-oil interaction
• Vacuum level: Atmospheric to slight vacuum (100–500 mbar) during separation

Employing Qeé Group’s automated control panels facilitates real-time monitoring of pH and temperature, enabling rapid adjustment and reducing typical acid value deviations by 15-20% compared to manual systems.

3. Bleaching: Color and Impurity Removal

The bleaching phase uses activated clay or carbon to adsorb pigments (carotenoids, chlorophyll) and residual metals. Key variables that must be optimized include clay dosage (1.5–3% by weight) and contact temperature (95–105°C). Insufficient clay results in poor color removal, while overdosing increases oil loss and costs.

A vacuum of 50–100 mbar is critical during bleaching to minimize oxidation risk. This step's efficacy is often quantified by a L*a*b* color scale, targeting a shift in L* (lightness) by +10 units and significant reductions in a* and b* values to ensure the oil’s visual appeal.

4. Deodorization: Eliminating Off-Odors and Volatiles

Deodorization is usually carried out under high vacuum (1–5 mbar) and temperatures ranging from 210–250°C. The process removes volatile compounds responsible for undesirable odors and flavors such as aldehydes and ketones. Duration is generally maintained between 2 to 4 hours, balancing completeness of deodorization and mitigating thermal degradation risks.

Automated deodorizer sections integrated in modern stainless steel systems maintain consistent vacuum and steam stripping flow rates, reducing batch variability and increasing throughput by approximately 10–15%.

Equipment Material and Automation: Enhancing Quality Assurance

Using stainless steel (SS316 or higher grade) for all contact surfaces in the refining system minimizes metal contamination, which can catalyze oxidation and discoloration. Stainless steel’s corrosion resistance also supports a longer equipment lifespan and simplifies sanitary maintenance.

The integration of advanced automation control systems—featuring programmable logic controllers (PLC) and human-machine interfaces (HMI)—affords operators with comprehensive oversight. This results in reduced human error, consistent batch-to-batch quality, and optimized resource utilization. Factories employing such technology report productivity improvements of up to 12% and quality compliance rates rising beyond 98.5%.

Practical SOP for Quality Troubleshooting

In case of abnormal color darkening after bleaching:

• Check clay dosage: Adjust to manufacturer’s optimal level (typically 2.2%)
• Verify bleaching temperature: Keep within 95-105°C window
• Inspect vacuum integrity: Repair leaks to maintain 50–100 mbar

For elevated acid values post-neutralization:

• Analyze NaOH concentration and dosing accuracy
• Ensure homogenized mixing during neutralization
• Confirm rapid and efficient soap skimming to prevent recontamination

Data-Driven Insights for Continuous Improvement