fractional distillation

Describe the process of fractional distillation

1. Crude oil is heated to vaporise it into a gas and passed into the fractionating column.

2. As the gas rises up the column, it cools down, as the column is cooler at the top. 

3. When the hydrocarbons reach a temperature lower than their boiling point, they condense into a liquid. This liquid is collected in trays and drained out.

4. The longer chain hydrocarbons condense lower down the fractionating column (where it is hotter) because they have higher boiling points.

5. The shorter chain hydrocarbons condense at the top of the column because they have lower boiling points.

Why do short chain hydrocarbons stay as a gas much longer than long chain

Because they have much lower boiling points so they we stay as a gas much longer as they rise up column until they reach a cool enough temperature to condense into liquid

Why do long chain hydrocarbons quickly condense back into a liquid

Long chain hydrocarbons have the highest boiling points so they will quickly condense back into a liquid and drain column early on because the column isn’t hot enough to keep them in their gaseous state

What are some examples of long chain hydrocarbons and short chain hydrocarbons

Long chain hydrocarbons- bitumen and heavy fuel oil

Short chain hydrocarbons - diesel , kerosene, petrol

What is crude oil

Crude oil is a fossil fuel deep under the ground and contains a mixture of different compound consisting mainly of hydrocarbons

How is crude oil formed

1. Crude oil is formed from the remains of dead plants and animals, particularly plankton.

2. These organic remains were covered by mud and sand, and buried in the earth.

3. Over millions of years, these organic remains were compressed under a lot of heat and pressure.

4. The heat and pressure chemically changed the organic remains into crude oil.

NOTE

Because crude oil takes so long to form it’s a finite resource (non renewable)

What is the properties of shorter chain hydrocarbons

They are most flammable so make the best fuels

Why are long-chain hydrocarbons bad fuels?

They are not very flammable or volatile. This means they are hard to combust for energy.

Fractionating column

What can crude oil be used for

Provide the fuel for most transport - diesel oetrol kerosene heavy fuel oil and LGP are used to fuel cars trains planes

What does the petrochemical industry use some of hydrocarbons from crude oil for

Use as a feedstock to make new compounds for use in things like polymers , solvents , lubricants and detergents