In its natural state, oil does not have many uses.
That is why we have to refine it. Refining oil means boiling it.
As the temperature rises, different compounds in the oil begin to boil. When a compound begins to boil, we take it out.
For instance, just before the oil reaches 104 degrees Fahrenheit, petroleum gas from the oil starts boiling, so we take it out.
Then, before the oil reaches 752 degrees Fahrenheit, the compound gasoline begins to boil, so we take that out.
The temperature keeps rising and the compounds are taken out as soon as they boil.
This process of refining is called fractional distillation.
In addition to making products, refining oil also creates waste. Refineries must treat the wastes involved in the process of making oil products in order to minimize air and water pollution.