Introduction to Deacidification in Oil Refining Plants
The deacidification process in oil refining plants is essential for removing free fatty acids (FFA) from crude oil obtained through pressing or solvent extraction. FFA causes unpleasant odors, accelerates rancidity, and reduces oil stability, making deacidification a critical step in edible oil refining.
Why is Deacidification Necessary?
- Prevents rancidity by reducing FFA-induced oxidation.
- Improves taste and odor for better consumer acceptance.
- Enhances oil stability for longer shelf life.
- Prepares oil for downstream processes (decolorization, deodorization, hydrogenation).
Without proper deacidification, high FFA levels can damage refining equipment and increase production costs.
Deacidification Methods in Oil Refining Plants
1. Alkali Refining (Chemical Deacidification) – Most Common Method
Alkali refining neutralizes FFA using caustic soda (NaOH) or other alkaline solutions, converting FFA into soap stock, which is then separated.
Working Principle:
- FFA reacts with alkali: FFA + NaOH → Soap (sodium soap) + Water
- The soap adsorbs impurities (phospholipids, pigments) and is removed via centrifugation or sedimentation.
Advantages of Alkali Refining:
- Highly effective for high-FFA oils (e.g., palm oil, soybean oil).
- Removes impurities (phospholipids, proteins, and pigments).
- Improves oil color and stability.
Disadvantages:
- Oil loss due to saponification.
- Requires wastewater treatment (soap stock disposal).
2. Physical Refining (Steam Distillation) – For Low-FFA Oils
- Uses high-temperature steam (200-250°C) under vacuum to volatilize FFA.
- Suitable for palm oil, coconut oil, and other low-phospholipid oils.
Advantages:
- No chemical usage, eco-friendly.
- Higher oil yield (no soap formation).
Disadvantages:
- Not suitable for high-phospholipid oils (e.g., soybean, rapeseed).
- Requires precise temperature control.
3. Enzymatic Deacidification (Emerging Technology)
- Uses lipase enzymes to break down FFA into glycerol and fatty acids.
- Eco-friendly but slower and costlier than traditional methods.
Key Equipment in Oil Deacidification Plants
1. Disc Centrifuge – Core Separation Equipment
The disc centrifuge is crucial for separating soap stock from neutralized oil.
- Structure & Working Principle:
Components: Drum, discs, transmission system, water distribution device. - Process:
- Oil-alkali mixture enters the drum (top or bottom).
- Centrifugal force separates soap (heavy phase) from oil (light phase).
- Clean oil is discharged via centripetal pump, while soap stock is removed separately.
Advantages:
- High separation efficiency (up to 99%).
- Continuous operation for large-scale refining.
2.Neutralization Reactor & Mixers
- Phosphoric/citric acid pretreatment converts non-hydratable phospholipids.
- Alkali mixer ensures uniform FFA neutralization.
3.Vacuum Dryer (For Moisture Removal)
- Removes residual water after washing to prevent oxidation.
Choosing the Right Deacidification System
| Production Scale | Recommended System |
|---|---|
| Small (1-10 TPD) | Batch Alkali Refining |
| Medium (20-50 TPD) | Semi-Continuous |
| Large (50+ TPD) | Fully Continuous Centrifugal System |
Benefits of Efficient Deacidification
- Higher-quality edible oil with improved flavor & shelf life.
- Reduced refining losses & chemical costs.
- Compliance with food safety standards (FFA < 0.1%).
- Enhanced efficiency in downstream refining (bleaching, deodorizing).
The deacidification process in oil refining plants is vital for producing high-quality edible oil. Whether using alkali refining, physical refining, or enzymatic methods, proper FFA removal ensures stability, taste, and marketability.
Need a customized deacidification solution? Contact our experts for disc centrifuge systems, batch refining, or continuous processing setups!