Edible oil refining equipment can be divided into batch refining equipment, semi-continuous refining equipment and full-continuous refining equipment according to the working principle.
Classification of edible oil refining equipment:
Batch refining equipment: the refining process is carried out in batches, and the production capacity is relatively limited; Suitable for small oil plants;
Semi-continuous equipment: some processes in the refining process, such as degumming and deacidification, are carried out in batches and need to wait; Deodorization section is continuous without waiting, which is suitable for medium-sized oil plants;
Fully continuous oil refining equipment: the oil refining process is fully continuous, with high degree of automation, high productivity and low labor cost, which is suitable for medium and large oil plants.
Process flow of edible oil refining equipment:
Crude oil → alkali refining degumming → decolorization → filtration → deodorization → filtration → refined oil;
1. Hydration degumming
Using the hydrophilicity of colloidal impurities such as phospholipids, a certain amount of water or electrolyte dilute solution is added to crude oil under stirring to make the colloidal impurities in crude oil absorb water, swell, condense and separate. In the process of hydration degumming, phospholipids are the main substances that can coagulate and precipitate except protein, mucus and trace metal ions.
2. Alkali refining and deacidification
All kinds of unrefined crude oil contain a certain amount of free fatty acids. The process of removing free fatty acids from oils and fats is called deacidification. Deacidification methods include alkali refining, distillation, solvent extraction and esterification. Alkali refining and steam distillation are widely used in industrial production.
3. Adsorption decoloration
Oil adsorption decoloration is the use of some substances (such as bleached soil, activated clay, activated carbon, etc. ).) It has a strong selective adsorption effect on pigments, and it can adsorb impurities such as pigments in oils and fats under certain conditions, thus achieving the purpose of decolorization. After the oil is treated with adsorbent, it can not only improve the color of the oil and remove colloid, but also effectively remove some trace metal ions and some substances that can cause hydrogenation catalyst poisoning, which provides good conditions for further refining (hydrodesulfurization) of the oil.
High temperature deodorization
It is a process of removing odor substances by steam distillation at high temperature and high vacuum by using the volatilization difference of odor substances in oil and triglyceride. The principle of steam distillation deodorization (also known as stripping method) is that steam passes through grease containing odor components, and the steam contacts with liquid surface, and the steam is saturated with volatile odor components and escapes according to their partial pressure ratio, thus achieving the purpose of removing odor components.