Basic workflow of refinery equipment:
Crude oil - degumming (washing) - deacidification (alkali refining) - decolorization (white clay adsorption) - dehydration (heating and drying) - product oil
Small-scale oil refinery machine uses crude oil (peanut oil, rapeseed oil, tea seed oil, soybean oil, sunflower seed oil, flax oil, walnut oil, sesame oil and other edible oils) for hydration, degumming, deacidification, decolorization, and deodorization by heating and stirring.
1. Hydration degumming
Hydration degumming is to use the hydrophilicity of peptizing impurities such as phospholipids, add a certain amount of water or diluted electrolyte solution to crude oil under stirring, so that the peptizing impurities in the crude oil will absorb water and expand, then condense, separate and finally they will be removed. In the process of hydration and degumming, the substances that can be aggregated and precipitated are mainly phospholipids, in addition to proteins, mucus and trace metal ions that are combined with phospholipids.
2. Alkali refining and deacidification
All unrefined crude oils contain a certain amount of free fatty acids, and the process of removing free fatty acids in grease is called deacidification. Methods of deoxygenation include alkali refining, distillation, solvent extraction, and esterification. What are widely used in industrial production are alkali refining and steam distillation (that is, physical refining).
3. Decolorization of fats
Fats by adsorption and decolorization is to use certain substances with strong selective adsorption of pigments (such as bleaching clay, activated clay, activated carbon) to absorb pigments and other impurities in the fats under certain conditions so as to achieve the purpose of decolorization. The grease treated by the adsorbent not only achieves the purpose of improving the oil color and removing the gum, but also can effectively remove some trace metal ions in the grease and some substances that can cause hydrogenation catalyst poisoning, thereby providing good conditions for further hydrogenation, deodorization of grease.
4. Oil deodorization
Oil deodorization is a process that use the difference in volatility between odorous components in oils and triglycerides to remove odorous substances by steam distillation under high temperature and high vacuum conditions. The purpose of the principle of steam distillation deodorization is that water vapor passes through the fat containing odor components and contacts the vapor-liquid surface. The water vapor is saturated with volatile odor components and escapes at the ratio of the partial pressure to achieve deodorization.