Used engine oil is one of the most common industrial wastes that can not be easily disposed of and is the only polluting factor for the environment and should not be allowed to enter the environment. Today, there are several ways to reuse it, the easiest way is to burn Used Engine Oil in furnaces for energy. However, due to the high price of this waste compared to other petroleum products, its use as a fuel is not cost-effective. The best option would be to recycle Used Engine Oil and recycle it into Engine Base Oil. Therefore, it will return to its original state and can be reused. There are various methods in the world today for recycling used engine oil, the most common of which is an acidic method of recycling. About 75% of countries use acidic methods to recycle base oils.
Recycling Used Engine Oil by Acidic Method:

• As mentioned, this is one of the most common methods. In this method, the Used Engin Oil is heated up to 400 degrees Celsius to evaporate the water and moisture in the oil. Using such methods will also cause light petroleum products with low boiling points in the oil to also evaporate during the boiling process.

• To dissolve metal and solid particles, reduce the temperature of the boiled oil to 35 degrees Celsius and only then add the sulfuric acid 98% to the boiled oil.

• In the next step, to separate sulfuric acid from the oil, the acidic oil is reheated to a temperature of 280 ° C in the vicinity of the Clay, where the pigment soil absorbs the acid in the oil

• At last, the base oil of the engine is separated from the acid sludge through filtration.

• Acid sludge from the process of recycling used engine oil is a bituminous substance with very acidic properties that is equivalent to 27% to 36% of free sulfuric acid.

• This substance has a strong smell and can be considered pollution that severely affects the environment negatively. Hence, it's very dangerous for the environment. This is due to the fact that engine oil is the most expensive petroleum product, in this method, about 20% of the recycling process is converted to acidic sludge.

Use of advanced FEMD-Tech technology in Engine Oil Recycling:
Pre-treatment
In this method, the used engine oil is first passed through a liquid-solid centrifuge. The solids and metal particles in the used engine oil are separated from the oil. The product of this process is 97% of used engine oil along with water and about 3% of solids and metal particles (Ash), which can be used for manufacturing insulation and asphalt strips.
Thin Film Reactor

• Thin film reactor is used to separate the water from the oil, which involves distilling the oil at a very low pressure close to vacuum.

• Thin Film technology uses a microfilter with pores at approximately two microns (2mm) in diameter in a rotating reactor about 11 meters in height.

• In a Thin Film reactor, the water in the oil is separated from the oil under vacuum (on atmospheric pressure) at a temperature of 70 to 85 ° C.

• At this stage, 5% to 7% of the water is separated from the oil, which is completely filtered and purified using the advanced technology of the purification system, and it is used in cooling towers.

FEMD Tech
After separating water from oil, using four reactors (FEMD-Tech) in vacuum conditions
from 190 to 250 ° C in different stages, engine base oil with different degrees (SN 150, SN 350,
SN 500, SN 750) is produced.
Advantages of using advanced FEMD-Tech technology in recycling Used Engine Oil:
A. Environmental benefits:

1. 98% sulfuric acid is not used or produced in the process.

2. Reducing environmental pollution.

3. Using green technology which has a crucial role in efforts to protect the environment.

4. Lack of industrial wastewater.

B- Economic benefits:

1. High efficiency in the production of base oils, spindle oil, and light petroleum products about 93% of input feed.

2. Ability to refine 31,600,000 liters of used engine oil annually and annual production of 29,462,000 liters of various engine base oils and light petroleum products based on international standards.

3.  Converting a large volume of oil waste into a marketable petroleum product.

C. Qualitative benefits:

1. Absence of sulfuric acid in manufactured products.

2. Having the conditions to enter global markets due to having superior quality in the production of engine base oil.

3. Ability to use world-renowned brands in the production of various types of engine oils (multigrade and mono-grade).

4. Lack of Aromatic substances in the base oil due to the use of NMP technology in the molecular separation of heavy particles.

5. Constant quality in all types of products in all stages of production.

D- Advantages of using advanced technology (Strategic High Technology)

1. Considerably convenient maintenance of refinery machines

2. No use of consumables in the short term.

3. As steel microfilters are used in reactors, they do not need to be replaced.