Palm Oil Bleaching Process

Palm oil bleaching process is a critical stage in the palm oil refining sequence, primarily used to remove pigments (like carotenoids and chlorophyll), trace metals, and oxidation products. This transformation changes the crude palm oil from a deep red/orange to a light yellow color.

Key Steps in the Bleaching Process

Pre-Treatment (Degumming): Before bleaching, crude palm oil is degummed—usually with phosphoric acid—to remove phospholipids and trace metals that interfere with the bleaching agent.
Addition of Bleaching Agent: A bleaching agent, most commonly acid-activated bleaching earth (bentonite or fuller’s earth), is added to the oil. Activated carbon may also be added to help remove darker pigments like chlorophyll.
Mixing and Reaction: The oil and clay mixture is heated to 90–125°C and agitated for 15–45 minutes. This occurs under a vacuum (50–125 mmHg) to prevent oil oxidation and improve the efficiency of the clay.
Filtration: The mixture is passed through a filtration system (such as vertical leaf filters or plate presses) to separate the clean oil from the “spent” clay.
Cooling and Testing: The bleached oil is cooled and tested for quality markers like color and residual phosphorus before moving to the final deodorization stage.

Bleaching Process of Palm Oil Refinery

• To avoid the influence by air and consume less clay, earth bleaching is processed under vacuum;
• The dosage of clay is based on the color requirement of final palm oil;
• Bleached oil is flushed through closed stainless steel filtration discs for less residue in the meal.
• To ensure stable production and easy operation, the filter is controlled automatically.

Factors affecting the palm oil bleaching process

The effectiveness of the palm oil bleaching process depends on several key factors:

• Temperature and Humidity: Crude palm oils were bleached at 105 ° C, for 30 min at 50 mmHg pressure. Afterwards, a deodorization step was performed at 260 ° C, 3 mbar, 1.5% steam for 60 min. You need to carefully control the temperature and humidity during the bleaching process to ensure optimal absorption.
• Quality of Refinery Machines: High-quality refinery machines are crucial for efficient bleaching. Make sure you use reliable and well-maintained equipment.
• Structure and Type of Bleaching Earth: The type and structure of the bleaching earth you use significantly impact the bleaching process. Choose the appropriate bleaching earth to achieve the best results.