The oil deodorization tower is core equipment in the oil refining process, designed to remove off-flavor substances (e.g., free fatty acids, aldehydes, ketones, alcohols, hydrocarbons) from crude oil, while also eliminating trace heavy metals, peroxides and heat-sensitive pigments. It is a key device for the finishing process after oil decolorization and deodorization.

Classified by operation mode, it includes batch-type, semi-continuous and continuous deodorization towers. Among them, continuous deodorization towers (e.g., tray-type, packed-type) are mainstream in large-scale oil processing due to high treatment efficiency and controllable energy consumption. Classified by heating method, it has direct steam heating and heat-conducting oil heating types, adapting to refining line demands with different capacities (50-1000 tons per day).

Working Principle

The oil deodorization tower is based on the vacuum steam distillation principle:

1. Vacuum environment: A high vacuum (residual pressure usually 2-6 mbar) is maintained inside the tower, which significantly reduces the boiling point of off-flavor substances (e.g., the boiling point of free fatty acids drops from above 260℃ under normal pressure to 180-240℃), avoiding oil oxidation and cracking caused by high temperature;
2. Steam stripping: Superheated direct steam is introduced into high-temperature (180-250℃) oil. As steam bubbles pass through the oil layer, they form azeotropes with off-flavor substances and carry low-molecular-weight off-flavor components into the gas phase;
3. Separation and discharge: Off-flavor substances in the gas phase are extracted by a vacuum pump together with steam, removed after condensation and separation, while the deodorized oil is discharged from the bottom of the tower to complete the deodorization process.

Advantages

1. Thorough deodorization effect: The content of free fatty acids in oil can be reduced to below 0.05%, and the removal rate of off-flavor substances is ≥98%, making the oil meet the sensory standards of national first-grade oil (no off-flavor, pure taste);
2. Improved oil quality: It simultaneously removes peroxides, trace heavy metals and heat-sensitive pigments, reduces oil acid value and peroxide value, and extends the shelf life of oil;
3. Controllable energy consumption: Continuous deodorization towers adopt waste heat recovery and staged heating design, with high utilization rates of steam and thermal energy, reducing energy consumption by 30%-40% compared with batch-type ones;
4. Strong adaptability: Parameters such as vacuum degree, temperature and steam volume can be adjusted to meet the deodorization needs of different oils (soybean oil, rapeseed oil, peanut oil, corn oil, etc.);
5. Stable operation: Continuous deodorization towers feature high automation and controllable oil residence time, avoiding oil quality degradation caused by local overheating and ensuring good product consistency;
6. Good environmental performance: The extracted odorous gas can be matched with condensation recovery and incineration treatment systems, without direct emission of harmful gases, complying with environmental protection requirements.