Where Does Gasoline Come From?
Most gasoline is obtained from crude oil or petroleum, the oil that comes from oil wells. Crude oil is a fossil fuel. That means it was created from the remains of tiny plants and animals that lived millions of years ago.
Those remains were covered with layers of sediment that were subjected to high pressures and temperatures for millions of years to produce the mixture of liquid hydrocarbons we call petroleum.
Hydrocarbons are organic chemical compounds made up of hydrogen and carbon molecules. Petroleum consists of hydrocarbon chains of all sorts of different lengths. The overall length of a particular hydrocarbon chain depends upon the number of carbon molecules present.
Crude oil is made up of a mixture of hydrocarbons that can be turned into a wide variety of products. For example, very short chains of one to four carbons form the petroleum gases known as methane, ethane, propane, and butane.
Hydrocarbon chains of five to seven carbons form solvents, including dry cleaning fluids and paint solvents. The gasoline we use for automobile fuel is made up mainly of hydrocarbon chains with seven to eleven carbons.
The hydrocarbon chains that are longer than twelve carbons are used for heavier fuel oils, including kerosene, diesel fuel, and heating oil; lubricating oils, such as engine oil; and solid forms of petroleum, including paraffin wax, tar, and asphalt.
Distillation occurs at an oil refinery. The gasoline is separated from petroleum by a process called “cracking.” At an oil refinery, a “cracking” unit heats the crude oil until most of it changes to a vapor.
The vapor is then passed over chemicals called catalysts. This causes the gasoline to separate from the rest of the petroleum. The vaporized gasoline is then drawn off and cooled back to a liquid state. Special additives are mixed with the gasoline to make it burn more smoothly in an automobile engine.
Once crude oil has been refined into gasoline, it’s usually pumped via a pipeline to large regional storage terminals. From these terminals, gasoline can be loaded into tanker trucks for delivery to specific gas stations where you purchase it for use in your automobile!