What refining process uses a catalyst to convert heavy hydrocarbons into lighter fuels?

Fluid catalytic cracking uses a catalyst to convert heavy hydrocarbons into lighter fuels.

In an FCC unit, heavy gas oils are heated and contacted with a finely powdered catalyst. The catalyst promotes the breaking, or cracking, of large hydrocarbon molecules into smaller molecules, including gasoline-range hydrocarbons, light olefins, and gases.

The catalyst becomes coated with carbon, called coke, during the reaction. It is continuously moved to a regenerator, where air burns off the coke and restores the catalyst’s activity. The regenerated catalyst then returns to the reactor.

FCC is different from hydrocracking, which uses hydrogen at high pressure and usually produces cleaner, more saturated products. FCC became especially important because gasoline demand encouraged refiners to turn heavier fractions into valuable transport fuels.