How is crude oil separated into its fractions?

Crude oil is separated into its various fractions through the process of fractional distillation. This method takes advantage of the different boiling points of the constituents of crude oil. When crude oil is heated in a distillation column, it vaporizes, and as the vapor rises, it cools at different temperatures. Each fraction condenses back into a liquid at its respective boiling point, allowing for the collection of various products such as gasoline, kerosene, diesel, and lubricating oils.

This process is efficient because it not only separates the crude oil into fractions but also allows for the recovery of each component in a manner that's tailored for its intended use. Other methods such as filtration and sedimentation would not be suitable for separating liquid mixtures like crude oil, as they rely on solid-liquid interactions or gravitational settling, which are not effective for separating mixtures of liquids with close boiling points. Simple distillation is also not appropriate for this task because it cannot separate components that have boiling points that are close to one another. Thus, fractional distillation is the correct and most effective method for this separation in the petroleum industry.