What factors affect palm oil refinery deodorization effect?

Palm oil deodorization is a process to remove odorous components from oils and fats by steam distillation under high temperature and high vacuum according to the difference of volatility between odorous components and triglycerides under the same conditions. According to palm oil deodorization principle, raising temperature, raising vacuum, increasing water vapor consumption and prolonging deodorization time are all helpful to deodorization, and are effective means to improve deodorization effect.

Deodorization tower in palm oil refinery plant

(1) Deodorization temperature control of palm oil refinery plant: High temperature helps to remove odor and shorten time. Experiments show that the deodorization time can be reduced by half if the deodorization temperature is increased by 17 degrees C. However, excessive temperature will result in hydrolysis or thermal polymerization of some oils, thus reducing the nutritional value and oxidative stability of oils and fats. However, too low temperature can not achieve the purpose of deodorization, and the smoke point of deodorized oil is lower. Generally, the deodorization temperature can be controlled from 230 250 C. The high temperature of palm oil deodorization can be produced by heating the heat conducting oil in the heat conducting furnace. At high temperature, it can destroy the thermosensitive pigments in the grease at the same time and play the role of thermal decolorization.

Note: After palm oil deodorization process, deodorized palm oil must be cooled below 70 C under vacuum condition to break the vacuum for fine filtration. Otherwise, the peroxide value of oil will increase and the oil color will redden due to oxidation.

(2) Deodorization residual pressure control of palm oil refinery plant: According to palm oil deodorization principle, direct steam injection is proportional to pressure. High vacuum can reduce the amount of direct steam, the loss of oil hydrolysis, and the distillation partial pressure, which is conducive to the volatilization of odor components and free fatty acids. At present, the absolute pressure of oil deodorization is generally between 600 and 133 pa.

For a specific deodorization system, if a multi-stage steam jet pump is used, its vacuum degree and pumping rate can not be adjusted flexibly. In order to ensure a stable vacuum effect, it is very important to ensure the working steam pressure to reach the design pressure. However, if other conditions of the steam jet pump operation, such as the change of cooling water temperature, the working steam pressure should also be adjusted accordingly. If the water temperature is high in summer, the working steam pressure should be increased correspondingly; if the water temperature is low in winter, the vacuum and the amount of air extraction needed for deodorization can still be satisfied by reducing the steam pressure properly. This can not only reduce the amount of working steam, but also ensure a stable working effect.

(3) Direct (stripping) steam consumption control of palm oil refinery plant: stripping steam acts as a carrier during deodorization to remove volatile components from oils and fats. Therefore, the more direct steam injected per unit time, the higher the steam flow rate, and the more conducive to the removal of odorous components in oils and fats. However, excessive steam can induce neutral oil to be carried out and atomized, resulting in increased oil refining loss.

(4) Deodorization time control of palm oil refinery plant: Deodorization time is related to steam injection. Generally, the amount of steam injection is more, and the deodorization time is shorter. Appropriate prolongation of deodorization time is conducive to the removal of odorous substances and thermosensitive pigments, but deodorization time is too long, will produce thermal polymerization of oil at high temperature, will lead to tar odor of oil and fat. Therefore, on the premise of guaranteeing deodorization effect, intermittent deodorization time is generally controlled at 4 h or semi-continuous continuous deodorization time is controlled at 25 ~ 100 min.