Oil Refining Review

Oil Refining Review

Most lubricating oils are currently obtained from distillation of crude petroleum. Due to the wide variety of petroleum constituents, it is necessary to separate petroleum into portions (fractions) with roughly the same qualities.

General scheme of the refining process. The refining process can be briefly described as follows:

Crudes are segregated and selected depending on the types of hydrocarbons in them.
The selected crudes are distilled to produce fractions. A fraction is a portion of the crude that falls into a specified boiling point range.

Each fraction is processed to remove undesirable components. The processing may include:

a.) Solvent refining to remove undesirable compounds.
b.) Solvent dewaxing to remove compounds that form crystalline materials at low temperature.
c.) Catalytic hydrogenation to eliminate compounds that would easily oxidize.
d.) Clay percolation to remove polar substances.

The various fractions are blended to obtain a finished product with the specified viscosity. Additives may be introduced to improve desired characteristics.