Palm Oil Deodorization Process

2026-05-08 07:40:05

Deodorization is the final and critical step in palm oil refining, transforming bleached palm oil into Refined, Bleached, and Deodorized Palm Oil (RBDPO). It is a physical stripping process that uses steam distillation under high vacuum and temperature to remove volatile impurities, odors, and free fatty acids (FFAs).

The Process Steps

Deaeration: Before heating, air is removed from the bleached oil under a vacuum to prevent oxidation and preserve oil quality.

Preheating: The deaerated oil is heated using heat exchangers, often recovering heat from outgoing hot deodorized oil to save energy.

Steam Stripping: High-pressure “live” steam is injected into the oil at temperatures between 240–260°C under a high vacuum (typically 2–6 mbar). The steam acts as a carrier, vaporizing and carrying away FFAs, aldehydes, and ketones that cause off-flavors.

Heat Bleaching: The oil is held at high temperatures for a specific period (25–100 minutes for semi-continuous systems) to thermally destroy heat-sensitive pigments like carotenes, resulting in a lighter-colored oil.

Cooling and Polishing: The oil is cooled to below 45°C and passed through polishing filters to remove any remaining trace impurities before storage.

Deodorization of Palm Oil

Palm oil deodorization is mainly a physical refining process belongs to steam deodorization. High pressure steam is introduced as a kind of stripping agent to remove various volatile components. The deodorization of palm oil usually processed at high temperature (>200°C) and low pressure.

In deodorization process of palm oil refinery, before deodorizing, the bleached palm oil is deaerated and heated firstly. Our palm oil deodorizer equipment employs a combined methodology. The bottom part designed for consistent quality, while the upper part is designed to remove free fatty acids. Through heat exchanger, the oil is cooled and ready for storage. In palm oil deodorization, the FFA level is first reduced from 3–5% to below 0.5% in a structured packing. And then the oil enters the deodorizer. As a kind of co-product of refinery plant, the free fatty acids are collected and stored.

What factors affect palm oil refinery deodorization effect?

Temperature Control
Temperature is the primary driver of the deodorization process, as it determines the vapor pressure of the free fatty acids (FFAs) and odoriferous compounds. While higher temperatures (typically 240–260°C) accelerate the stripping process and facilitate “heat bleaching” to remove carotenes, excessive heat can trigger the formation of trans-fatty acids and glycidyl esters. Precise control is necessary to maximize impurity removal without degrading the oil’s nutritional value or natural antioxidants like Vitamin E.

Vacuum Pressure
The vacuum level is critical for lowering the boiling points of the volatile components, allowing them to evaporate at temperatures below their normal boiling points. Maintaining a high vacuum (usually below 3 mbar) protects the oil from oxidation by removing oxygen from the system. A deeper vacuum increases the relative volatility of the impurities, which improves stripping efficiency and significantly reduces the amount of steam required for the process.

Stripping Steam Injection
Direct steam injection serves as the mechanical vehicle for carrying away vaporized impurities. As the steam bubbles through the hot oil, it creates a large surface area for mass transfer, allowing volatile odors and acids to migrate into the steam phase. While increasing the steam rate improves the deodorization effect, it must be balanced to prevent “entrainment,” where droplets of valuable neutral oil are swept away into the distillate, leading to unnecessary production losses.

Residence Time
Residence time refers to the duration the oil is exposed to the high-temperature, high-vacuum environment. Adequate time is required for the chemical reactions involved in heat bleaching and the physical migration of volatiles to the oil-steam interface. However, modern refinery designs aim to minimize this duration using packed towers; shorter residence times at high temperatures help prevent the development of “off-flavors” caused by thermal decomposition and reduce overall energy consumption.

Feedstock Pre-treatment
The success of the deodorization stage is heavily dependent on the quality of the oil entering the system from the degumming and bleaching stages. If the oil still contains high levels of soaps, gums, or mineral traces, these can act as catalysts for oxidation during the high-heat deodorization phase. Ensuring that the bleached oil is clean and low in moisture allows the deodorizer to focus strictly on removing flavors and odors rather than correcting previous refining failures.

Surface Area and Mass Transfer
The mechanical design of the deodorizer, specifically the contact area between the oil and the stripping steam, dictates the rate of purification. Modern systems often use thin-film or packed-column designs to maximize the surface-to-volume ratio. By spreading the oil into a thin layer or fine droplets, the distance volatiles must travel to escape the liquid is reduced, significantly increasing the “deodorization effect” compared to traditional bulk-tank methods.

Palm Oil Deodorization Process

Palm Oil Deodorization Process

The Process Steps

Deodorization of Palm Oil

What factors affect palm oil refinery deodorization effect?

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