Crude oil refining mainly includes degumming, deacidification, decoloration and deodorization, with the aim of removing colloid, free fatty acid, pigment and peculiar smell. There are several technical difficulties in production:

1. Fluctuation of raw materials: Different batches of crude oleic acid have great differences in price and colloid, and the fixed parameters are difficult to adapt, resulting in unstable quality of finished products. It is necessary to test batch by batch and adjust the process flexibly.

2. Refining loss: Neutral oil is easily entrained in the deacidification process, and improper control of alkali liquor will increase the loss, reduce the oil yield and compress the profit.

3. Decolorization balance: The amount of white clay needs to be weighed. Add too little, the color is not up to standard; Adding too much will adsorb a lot of neutral oil, increase the cost and accelerate the oxidation of oil. Decolorization should be carried out in vacuum environment as far as possible.

4. Deodorization control: It is difficult to control the temperature under high temperature and high vacuum conditions. It is difficult to remove the odor due to insufficient temperature; When the temperature is too high, the oil is easy to produce trans fatty acids and lose nutrients, and the oil will have a aftertaste in the later stage, so the equipment requires high vacuum tightness.

5. Grease oxidation: Air and metal ions enter the process, and the refined oil is easy to oxidize and shorten the shelf life.

6. Environmental protection operation and maintenance: Soapstock, waste clay and wastewater are generated, and the environmental protection treatment cost is high; Heat exchangers and vacuum components are easy to scale and block, and need regular maintenance.

Edible oil refining is a process with balanced indexes. With stable refining equipment and standardized operation, the oil quality can be stabilized and the loss and operation and maintenance pressure can be reduced.