What should be paid attention to when using a deodorization tower in daily life

Source： Release date： 2026-09-01

Information summary：1、 Normal operation process parameter control (daily production) 1. Vacuum degree (deodorization lifeline) Absolute pressure stability control ≤ 3-4 mbar; Vacuum fluctuations can directly cause incomplete deodorization, oil discoloration, and lingering aftertaste. Check the steam jet pump and circulating cooling water temperature. If the cooling water temperature is too high, it wil

1、 Normal operation process parameter control (daily production)
1. Vacuum degree (deodorization lifeline)
Absolute pressure stability control ≤ 3-4 mbar; Vacuum fluctuations can directly cause incomplete deodorization, oil discoloration, and lingering aftertaste.
Check the steam jet pump and circulating cooling water temperature. If the cooling water temperature is too high, it will directly lower the vacuum; Regularly check the sealing of flanges, manholes, valves, and stuffing boxes to prevent air leakage.
It is strictly prohibited to leak a large amount of air during operation: air enters the tower, causing rapid oxidation of high-temperature grease, deepening of color, and increase in peroxide value.
2. Deodorization temperature
Conventional vegetable oil should be controlled at 240-255 ℃ and not exceed 260 ℃; Insufficient temperature and insufficient deodorization; Excessive temperature can cause trans fatty acids, oil polymerization, and darkening of color.
Compare the temperature at multiple points on the tower, middle, and bottom to avoid local overheating; The decrease in heat exchange efficiency of the heat exchanger should be cleaned up in a timely manner.
3. Direct steam (stripping steam)
Steam must be dry and saturated, without condensation water; Carrying water can cause oil hydrolysis and an increase in acid value.
Control the oil weight by 3-8% for steam extraction, and fine tune according to the level of FFA free fatty acids; The steam is too small and the deodorization is poor. The excessive steam causes the foam in the tower to surge, entrainment and overload of fatty acid trap.
Regularly inspect the steam nozzle inside the tower to prevent scaling and blockage of the nozzle, resulting in uneven distribution of steam stripping and insufficient local deodorization.
4. Liquid level and residence time inside the tower
Strictly control the liquid level inside the tower, neither too high nor too low; If the liquid level is too high, foam will overflow and entrain; The liquid level is too low, the oil retention time is insufficient, and the deodorization is not qualified.
Control the effective residence time of grease in the tower, generally 40-60 minutes; If the residence time is too short, the odor will not be completely removed, and if it is too long, the thermal deterioration of the oil will worsen.
Matching the inflow and outflow of oil, DCS should try to stabilize the load as much as possible and avoid frequent and significant flow adjustments.
5. Prevention and control of foam and mist entrainment
The raw material FFA is too high and the colloid is not removed completely, so foam is easy to form in the tower; Serious foam will bring oil into vacuum system and fatty acid trap.
When foam rises, properly reduce the feed rate, fine tune the direct steam volume, and properly lower the temperature if necessary; Do not forcefully open the direct car.
6. Heat exchange and discharge cooling
After deodorization, the oil must be rapidly cooled in a vacuum environment, and the oil temperature should be lowered to below 80 ℃ before breaking the vacuum; High temperature oil is prone to oxidation and deterioration when exposed to air.
Regularly inspect the heat exchanger and promptly clean up coking if the heat exchange efficiency decreases.
2、 Key points for startup and shutdown operations (prone to errors)
Power-on sequence
1. Start the vacuum system first, and after the vacuum reaches the process indicators, enter the oil;
2. After the oil enters the tower and rises to 100-160 ℃, gradually open the direct steam; Introducing a large amount of direct steam at low temperatures can cause a significant amount of condensed water and hydrolysis of fats and oils.
3. The temperature gradient should be gentle, and rapid and rapid heating is prohibited.
Shutdown sequence (very critical)
1. Stop oil injection first and turn off the direct steam.
2. Maintain high vacuum, drain the oil from the tower, and cool the oil to below 80 ℃ under vacuum.
3. Vacuum breaking is only allowed after the oil temperature has dropped; High temperature state breaks the vacuum, a large amount of air enters, and the oil is directly oxidized and scrapped.
4. Stop the vacuum system again; Ensure proper drainage of the jet pump and condenser.
Emergency shutdown: First cut off the heating, keep the vacuum, and quickly export the hot oil from the tower for cooling. Do not break the vacuum at high temperatures.
3、 Key points of daily inspection (must be checked every shift)
1. Instruments: Maintain operational records of multi-point temperature, vacuum pressure, liquid level, inlet and outlet oil flow rate, and steam pressure on the tower body.
2. Sealing points: manhole, flange, valve, pump packing box, check for air leakage; A small leak can destroy the vacuum.
3. Vacuum system: working status of jet pump, temperature and pressure of circulating water, liquid level of fatty acid trap, timely discharge of fatty acids.
4. Steam system: Check whether there is condensed water in the direct steam pipeline, whether the steam trap is working properly, and prevent water from entering the tower.
5. Pump: The discharge shielding pump is in operation to prevent evacuation and cavitation.
6. Observe the fatty acid trap and sight glass to see if there is a large amount of oil, and determine the situation of mist entrainment.
4、 Maintenance and Regular Maintenance
1. Steam injection pipes and distributors should be regularly cleaned to prevent coking, scaling, and blockage, ensuring even distribution of stripping steam.
2. Fill type deodorization tower, regularly inspect and clean the coking on the surface of the filling material; Coking of fillers will reduce the gas-liquid contact efficiency and deteriorate the deodorization effect.
3. Regularly inspect the thermal oil system, use high-temperature resistant graphite gaskets for high-temperature pipeline gaskets, and ordinary gaskets are prone to failure and air leakage at high temperatures.
4. During long-term shutdown, the residual oil inside the tower should be drained to prevent oil oxidation and coking; The tower body is protected by nitrogen gas to prevent inner wall corrosion.
5. When entering the tower for maintenance, it is necessary to cool down, break the vacuum, ventilate and replace, perform gas detection, and carry out confined space operations with tags and locks.
5、 Common Problems and Risk Reminders
1. Continuous deterioration of vacuum: Priority should be given to identifying the leakage point, followed by checking the working conditions of the cooling water and jet pump.
2. Rebound of oleic acid value in finished products: direct condensation water is carried by steam, and the raw material gum is not completely removed.
3. Deepening of oil color and excessive peroxide value: system leakage, high temperature contact with air; Staying for too long; The temperature exceeds the standard.
4. There is still an odor after deodorization: insufficient vacuum, insufficient temperature, insufficient residence time, and insufficient direct steam volume.
5. Foam entrainment and large amount of oil in the trap: high feed FFA, large foam, high liquid level, large direct steam opening ratio.
6、 Safety precautions
1. High temperature equipment to prevent burns; High temperature grease under negative pressure prevents the risk of thermal spray.
2. It is strictly prohibited to open manholes and handholes under high temperature conditions. Cooling and breaking the vacuum must be completed.
3. The thermal oil pipeline should be strictly guarded against leakage to prevent high-temperature thermal oil from catching fire when exposed to air.

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