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The Refining Process

As mentioned previously, a barrel of crude oil has a mixture
of all sorts of hydrocarbons in it. Oil refining separates everything
into useful substances. Chemists use the following steps:
1. The oldest and most common way to separate things into
various components (called fractions), is to do it using the
differences in boiling temperature. This process is called fractional
distillation. You basically heat crude oil up, let it vaporize and then
condense the vapor.
2. Newer techniques use chemical processing on some of the
fractions to make others, in a process called conversion. Chemical
processing, for example, can break longer chains into shorter ones.
This allows a refinery to turn diesel fuel into gasoline depending
on the demand for gasoline.
3. Refineries must treat the fractions to remove impurities.
4. Refineries combine the various fractions (processed,
unprocessed) into mixtures to make desired products. For example,
different mixtures of chains can create gasolines with
different octane ratings.
The products are stored on-site until they can be delivered to
various markets such as gas stations, airports and chemical plants.
In addition to making the oil-based products, refineries must also
treat the wastes involved in the processes to minimize air and
water pollution.
In the next section, we will look at how we separate crude oil
into its components.

Fractional Distillation

The various components of crude oil have different sizes,
weights and boiling temperatures; so, the first step is to separate
these components. Because they have different boiling
temperatures, they can be separated easily by a process

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