What is the principle of solvent extraction used in cooking oil processing industry?

Solvent extraction technology is widely used in various industry. In cooking oil processing industry, it is one of main method to extract oil from oil seeds. Its principle is liquid-solid extraction, using organic solvent to extract oil from oil seeds, because of oil more easily soluble in organic solvents, and the oil residual rate can be less than 1%.

In cooking oil processing industry, the solvent usually used is N-hexane, which is circulating used in the cooking oil solvent extraction plant. The detailed steps is as following:

Four steps in cooking oil solvent extraction plant

The first step: Spraying the N-hexane on oil seeds or oil pressing cakes that have been pretreated ahead.

The second step: Using D.T.D.C system to make the wet meal drying, and recycle the N-hexane to condensate recovery system.

The third step: Through evaporating and stripping, the N-hexane is also recycled to condensate recovery system.

The last step: Condensate and recycle the N-hexane to reuse.

Solvent extraction technology used in cooking oil processing industry can be divided into three kinds of processes.

1. Directly leaching method:

Suitable for oil seeds with a low oil content, like soybeans, after pretreatment, the soybeans will be directly sent into cooking oil solvent extraction plant.

2. Pre-squeezing-leaching method:

Suitable for oil seeds with oil content more than 30%, like groundnut seeds, it should be pressed by cooking oil press machine firstly, and then the pressing cake with relatively high oil content will be sent to cooking oil solvent extraction plant.

3. Puffing-leaching method:

To making rice bran oil, usually use puffing-leaching method. It is an oil-making method that has arisen in the world in the 1990s. The oil seeds are firstly extruded by puffing machine and then sent into cooking oil solvent extraction plant. This process has many advantages such as low investment, low power consumption, good leaching effect, strong ability and short leaching time, also it is the future development direction of the cooking oil processing industry.

Rice bran pretreatment and puffing process before leaching

Some people think solvent extraction technology belongs to chemical method, and the oil got from cooking oil solvent extraction plant is unhealthy. Here, I must declare that solvent extraction is physical method, because it don't have real chemical reaction. In addition, the oil got whether from pressing plant or solvent extraction plant must be sent to edible oil refinery plant, and then the oil can be qualified the national standards.

If you want to use solvent extraction technology to make cooking oil, please tell us what your oil seeds is and how many tons per day you want to process. In addition, I have to remind you that considering cost and economic benefit, more than 30tpd input capacity is suitable to use solvent extraction technology. Henan Doing Company can provide you technical support and factory price machines. Welcome to contact us!