Engine oil is a commonly used lubricant in vehicles. It can reduce the generation of friction heat in internal combustion engines and is also conducive to heat conduction. Waste engine oil refers to waste lubricating oil that has been replaced and contaminated by impurities, oxidized or thermally decomposed during the use of various vehicles, ships and other machinery.
 
Waste engine oil contains a large amount of impurities, which will accelerate the wear of mechanical equipment and cause serious corrosion to the equipment. Waste acid and heavy metals in waste engine oil can cause symptoms such as anemia and nausea, and even affect the human nervous system. Studies have shown that 500 g of waste engine oil can pollute 1000t of clean water, which is equivalent to polluting the water consumption of 7 people for about a year. Pour or burn waste engine oil not only wastes resources, but also causes serious environmental pollution and even harms human health. Fully and reasonably utilize waste engine oil to regenerate it into refined engine oil or refine it into fuel oil, which can not only alleviate the contradiction of oil shortage in my country, but also promote environmental protection and turn waste into treasure, creating considerable economic benefits. Therefore, the regeneration and utilization of waste engine oil is very important.
 
At present, the main methods for regenerating waste oil are solvent refining and hydrotreating. The regenerated oil obtained by these two methods can be used as lubricating oil base oil in the engine. The solvent refining method mainly extracts and separates the ideal components and non-ideal components in the oil according to the different solubility of the extractant. The solvent refining method is widely used in production practice because it has the advantages of low requirements for equipment and instruments, simple operation, high yield, and the solvent can be recycled multiple times.
 
The principle of solvent refining is to extract and separate according to the different solubility of the solvent in the ideal components and non-ideal components in the lubricating oil. Commonly used solvents are furfural, phenol and nmp (n-methylpyrrolidone).
 
LCT centrifugal extractor. The raw oil and NMP extractant are injected into the centrifugal extractor in a certain proportion. With the help of the rotation of the drum, the two phases are quickly mixed and dispersed through the impeller to complete the mixed mass transfer process. The mixed liquid enters the drum under the action of the vortex disk. Under the action of centrifugal force, the two-phase liquid is quickly separated and discharged from the body through different outlets to complete the two-phase separation.