How does crude oil get separated into gasoline, kerosene, and lubricating oils?

Crude oil is separated into various components, including gasoline, kerosene, and lubricating oils, primarily through a process called fractional distillation.

The Distillation Process

Crude oil is heated in a furnace to temperatures between 315 and 400 °C (600 and 750 °F) and then fed into a tall fractionating column. Inside the column, the oil vaporizes and rises through a series of trays. As the vapors rise, they cool and condense at different levels based on their boiling points. Lighter constituents, such as those used for gasoline, collect near the top, while heavier components remain lower in the column.1

Specific Fractions

• Gasoline: This is derived from the lighter fractions of crude oil. During distillation, light straight-run naphtha is typically withdrawn as an overhead product.1
• Kerosene: Often referred to as a middle distillate, kerosene is withdrawn as a sidestream from the column, typically with a boiling range of 150–245 °C (300–475 °F).12
• Lubricating Oils: The residue remaining at the bottom of the column is often further distilled under vacuum conditions to produce the heavy oils required for manufacturing lubricating oils.1