Refining

Refining is a process in which crude oil or other oils are distilled without changing the molecular structure. Because in the petroleum refining process, crude oil must undergo a series of processes to obtain useful petroleum products. Generally speaking, it refers to petroleum refining, that is, cracking crude oil into fuels such as kerosene, gasoline, diesel, heavy oil used in internal combustion engines, and producing chemical raw materials such as olefins and aromatic hydrocarbons. The current refineries are generally oil-based combined refining plant.

The heaviest vacuum residue is produced by solvent deasphalting process to produce deasphalted oil and petroleum asphalt, or delayed coking process to crack heavy oil into fuel oil component and by-product petroleum coke. Lubricating oil refineries produce various kinds of special industrial oils such as engine lubricating oil, mechanical oil, transformer oil and hydraulic oil through solvent refining, solvent dewaxing and supplementary hydrogenation. Hydrogenation processes are now used more in the production of fuel oils and lubricants. In addition, refineries that produce raw materials for petrochemicals also use a hydrocracking process.