Crude oil & Cracking

The different liquids that make up crude oil can be separated by

Fractional distillation because they have different boiling points. This is because the hydrocarbons have different molecule sizes and masses.

Fractional distillation in an oil refinery

Fractional distillation is an example of a physical process - there are no chemical reactions. The fractionating tower is hot at the base and cooler at the top.

Fuel oil

Fuel for big ships

Diesel (oil)

Fuel in diesel engines

Cracking paraffin in a lab

Heat paraffin in test tube. Move Bunsen to and from the paraffin to the catalyst. Alternate between the the two until the paraffin vaporises and catalyst glows red. Heated paraffin vapour cracks and small alleged collect at the end of the tube. Gases travel done tube and are collected through water using a gas jar

Bitumen

Roads and pavement felting

Steps

1. Oil is heated and pumped into the bottom of the tower where is vaporises. 2. As the vaporized oil rises it cools and condenses. 3. Large molecules that have high bp condense at the bottom. 4. Small molecules that have low bp and condense further up the column. 5. The liquids are collected on different trays and are separated into different fractions.

Refinery/Petroleum gases

Bottled gases and chemicals

Crude oil is a

Complex mixture of hundreds of different covalent compounds most of which are hydrocarbons. Crude oil is a non-renewable resource

Cracking

Cracking is a form of thermal decomposition. Smaller hydrocarbons are more in demand than long chain hydrocarbons. This is because they are more flammable and therefore better as fuels.

There are different predictions when crude oil will run out because

Different scientists have Carrie out different tests and experiments. There are also now renewable sources of energy like wind energy from wind turbines

Crude oil

Is a fossil fuel which comes directly from the earths crust. 1. Microscopic plants and animals die and fall to the sea bed. 2 layers of sand and mud form on top. 3. High pressure from above and high temps from below cause oil to form. 4. Oil obtained by drilling

Kerosene (paraffin)

Jet fuels,

Bottom of column

Large molecules High dp Doesn't flow easily Not very volatile Doesn't ignite easily

Uses of petroleum

Make fuels for transport heating and electricity. Used to make plastics and hundreds of petrochemicals

Refining oil in the lap

Mineral wool soaked in petroleum in a test tube. The mixture is heated and the compound with the lowest no evaporates first. This travels in the tube into a tub of cold water where it condenses into a liquid. The liquid obtained is a fraction of crude oil. Once this has all been boiled off the temp will rise and further fractions will be obtained Colours darken. Viscosity increases

Gasoline

Petrol for cars

Conditions for cracking

Silica/lumina catalyst Temp between 600 &700C

What happens during cracking

When cracking it produces a short chain hydrocarbon with a carbon carbon double bond which makes the compounds reactive. They are used to make plastics. Also there are fewer short chained hydrocarbons produced at first

Naptha

chemical feedstock for making plastics dyes drugs explosives, paints