Crude Fractional Distillation And Cracking Flashcards
What is crude oil formed from and what is it
It’s a fossil fuel formed from the remains of plants and animals mainly plankton that does millions of years ago and were buried in the mud
Why do we use fractional distillation
To alert water crude oil into fractions
Called hydrocarbon fractions
What’s the first step of fractional distillation
The oil is heated until most of it is tuned into a gas
The gas enters the fractionating column and the remaining liquid is drained away
What’s the gradient in the column
A temperature gradient
It’s hits at the bottom and gets cooler as you go up
What hydrocarbons are separated first and why
The longer hydrocarbons which have high boiling points therefore they will condense back into liquids and drain out fo the column
Why do the shorter hydrocarbons drain out near the top
They have lower boiling pints so will condense at the lower temperatures
What is the crude oil separated into
Different fractions which each fraction containing a mixture of hydrocarbons which have similar carbon atoms which similar boiling points
Why does the petrochemical industry use crude oil
As feedstock to make new compounds for use in things like polymers, solvents, lubricants and detergents
Why do you get a large variety of products of crude oil
Carbon atoms can bond together to form different groups which contain similar compounds with many properties in common
What is cracking and why is it used
It means splitting up long chained hydrocarbons into more useful short chained hydrocarbons which are flammable and make good fuels
What happens to the long chained molecules that come out from fractional distillation
They are turned into smaller and more useful ones by cracking
What molecules does cracking make
Alkanes and Alkenes
What type of reaction is cracking
A thermal decomposition reaction
It means breaking down molecules by heating them
What do you do first to the hydrocarbon in catalytic cracking
You heat the hydrocarbon to vaporise it (turn it into a gas)
What happens to the vapour in cracking
And what does this do to the molecules
It’s passed over a hot powdered aluminium oxide catalyst
The long chain molecules split apart on the surface of the specks of the catalyst
