Peanuts has high oil yield, usually peanut oil pretreatment machine is adopted to obtain fragrant peanut oil. Fragrant peanut oil has a unique flavor and high nutritional value, it is a very popular and important edible oil in our daily life.
The complete peanut oil pretreatment processing line is:
Cleaning→ classification→ drying→ crushing and peeling→hot roast →cooling→ steam cooking→ peanut oil press machine.
1. Peanut cleaning. There are impurities in peanuts before processing. The residues include mud, stem or leaves, without cleaning, they will influence peanut oil and oil cakes quality, at the same time, they will absorb some fat and reduces oil rate. If there are some sand or metal, there may be accident in the future processing. There are many methods to clean them and it depends. If the impurities are light in weight like grass, stem and leaf, we can choose wind, using air stream to blow them away. If the residues are small in size, we can select them by screen. To the metal material like steel, we choose electromagnet or permanent magnet to separate them.
2. Classification. The sizing screen isolates immature granulocytes, moldy grain, broken grain and other parts of peanut raw materials imperfection.
3. Drying. The air dryer can be used for drying peanut raw materials. Control peanut moisture between 5% -6% after drying, and reduce the temperature of oil particles below 40℃ with cold air quickly.
4. Peanut crushing and peeling. The roll crusher removes the red layer of peanuts, the flat wind suction screen will suck the red layer after peanut crushing. The isolated red peanut mantle can be used as pharmaceutical and chemical raw material. Shelling is to reduce shells absorption to fat and improve oil rate; increase the processing capacity and lower the wearout of press machine; process good quality oil cakes and make them widely used.
5. Hot roast. Send between 25% and 30% of peanut materials to the hot air oven and heat them to 180℃~ 200℃. Roasting temperature is a key factor in producing fragrant peanut oil.
6. Cooling. Rapid cooling is necessary after roasting to prevent oilseeds from sticking and being spontaneous. The crusher breaks the peanut into crushed granules.
7. Steaming and roasting. Vertical steam boiler processes material with a discharge temperature of 108 ~ 112℃, and 5% to 7% humidity, which guarantees a rich peanut oil flavor. The indirect steam pressure of the steam boiler must not be less than 0.6 mPa.
8. Peanut Kernels Cooking. Cooking is one of the important processing steps in oil extraction. We should add 8-10% water before cooking. Peanut after cooked called ripe billet, and the pressing process is called hot press. Peanuts are mainly hot press. The cooking process influences directly on the smooth press, oil rate and oil cake quality. When the moisture content is close to 1-2% and the temperature reaches 120-130℃, peanut is suitable to finish cooking and begin to press.
9. Peanut oil press. Here we adopts screw oil press which is widely used in small sized oil plant. The adoption of the screw oil press machine maintains the press temperature of 135℃, the humidity of 1.5% to 2%, the residue of the peanut press cake from 9% to 10%. Simple operation and high pressure ensures continuous processing.
Crude peanut oil after precipitation and filtration of the vertical leaf filter is sent to the peanut oil refining plant. The peanut oil cake after the oil pressing process is sent to peanut oil solvent extraction plant for secondary extraction. Crude oil extracted after refining is sold as ordinary oil.