Like the evolution of the planet, life and technology, the oil refining industry has been growing in complexity since its founding in 1859. Refinery industry facilities include physical and chemical processes. Physical changes, such as salting, distillation, filtration and evaporation, are related to separation. Chemical changes such as isomerization, hydrogenation, oxidation and polymerization are related to chemical reactions. The operating units of refinery industry facilities are related to process units. The main purpose of refinery units is to extract useful materials from crude oil. An oil refinery and a petrochemical plant are like living organisms that are highly interdependent.