Fractional Distillation of Crude Oil Flashcards
Why is crude oil so valuable to humans?
We depend on it to provide us with fuels for transport, heating and for the manufacture of a wide range of chemicals
How is crude oil formed?
2
It was formed mainly from the bodies of tiny sea creatures that died millions of years ago.
These remains were covered in layers of mud and silt which allowed bacteria to decompose the remains, turning them into crude oil and natural gas
Why does crude oil have to be refined?
When it is pumped from under the ground or sea if is a thick, black liquid with an unpleasant smell that doesn’t burn easily
What is fractional distillation?
The separation of crude oil into a number of useful parts by heating crude oil and separating its various parts based on their boiling points
What are fractions of substances?
The substances produced from fractional distillation which are separated as groups of compounds with similar boiling points
What is first done to crude oil when its purchased?
It is analysed by refinery chemists to determine its quality
What is done to the crude oil after its quality has been analysed?
It is heated in a furnace to a temperature of about 600 degrees Celsius which boils the crude oil and allows it to partially turn to vapour
What happens to the crude oil after it has been heated in a furnace?
It enters the bottom of the fractionating column
What is found inside the fractionating column which separates the vapour?
Trays
What are found on the trays in a fractionating column?
Bubble caps
What are the functions of the bubble caps on the trays of a fractionating column?
(4)
They slow down the rate at which the vapour rises through the fractionating column
They allow the vapour to pass through the trays
They increase the contact time between the vapour and the liquids in the column
These three functions help to achieve a better separation of the substances in the mixture
What parts of the fractionating column are kept at a constant high temperature?
The bottom of the column is kept at a high temperature and this decreases as you move up the column
What effect does the decreasing temperature as you move up the column have on the separation of substances?
(2)
The larger hydrocarbon molecules with higher boiling points turn to liquids nearer the bottom of the column
The smaller hydrocarbon molecules remain vaporised and rise up the column until they reach a temperature equal to their boiling point where they then condense to a liquid
What happens to the hydrocarbon molecules after they have condensed in the fractionating column?
They are collected in the trays which are connected to an outlet which can then be attached to a tank or pipes
List the eight different fractions beginning with the heaviest
Bitumen Fuel oil Lubricating oil Diesel oil (gas oil) Kerosene (paraffin oil) Naptha Petrol (light gasoline) Refinery gas (petroleum gas)
At what temperature does bitumen condense to a liquid?
Above 500 degrees Celsius
What are the uses of bitumen?
3
It is the black tar used to surface a road
It can be used for waterproofing
It can be used for roofing
At what temperature does fuel oil condense to a liquid?
At approximately 450 degrees Celsius
What are the uses of fuel oil?
3
Fuel in ships,
Fuel in power stations
Fuel in heating plants
At what temperature does lubricating oil condense to a liquid?
At approximately 400 degrees Celsius
What are the uses of lubricating oil?
It is mainly used as a lubricant to reduce the wear and tear in engines
At what temperature does diesel oil/gas oil condense to a liquid?
300 degrees Celsius
What are the uses of diesel oil/gas oil?
5
Fuel in trucks
Fuel in buses
Fuel in trains
Fuel in cars
Domestic heating
At what temperature does kerosene/paraffin oil condense to a liquid?
At approximately 200 degree Celsius
