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
dewaxing to remove compounds that form crystalline materials
at low temperature.
hydrogenation to eliminate compounds that would easily
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.