Britannica Sources used in this answer

How is crude oil refined into gasoline, diesel fuel, jet fuel, and heating oil?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

petroleum production A semisubmersible oil production platform operating in water 1,800 metres (6,000 feet) deep in the Campos basin, off the coast of Rio de Janeiro state, Brazil.

Crude oil is refined into products like gasoline, diesel, jet fuel, and heating oil through a combination of physical separation and chemical conversion processes.12

Separation

The primary method for separating crude oil is fractional distillation. Crude oil is heated and pumped into a tall fractionating column, where it separates into various "sidestreams" based on boiling points. Lighter components rise to the top, while heavier components remain at the bottom. This process yields intermediate products such as naphtha, kerosene, and gas oils, which serve as the foundation for final fuel products.3

Conversion

Because distillation alone cannot meet the high demand for transportation fuels, refineries use conversion processes to chemically alter molecular structures. Key methods include:2
* Cracking: This process breaks heavy, large hydrocarbon molecules into lighter, more valuable ones like gasoline and diesel.4
* Hydrocracking: Using hydrogen and catalysts at high pressures, this process converts heavy gas oils into high-quality jet fuel, diesel, and gasoline.54
* Reforming: Often used to improve the quality of naphtha, turning it into high-octane gasoline.5

These processes allow refineries to maximize the yield of essential fuels from crude oil.62