Crude Oil Flashcards
What is crude oil
A mixture of hydrocarbons
What do all forms of crude oil contain
Alkanes of varying chain lengths
Small amounts of molecules that also contain other elements
What is a fraction
Collection of molecules which have similar numbers of carbon (similar BPs)
At the top of fractionating column
Smaller molecules (more volatile) Ignite easily Low BP less viscous Lighter in colour
At the bottom of fractionating column
Bigger molecules (less volatile) Less flammable High BP Smokier flame More viscous Darker in colour
How does fractional distillation work in the industry
1) crude oil is heated + turned into a vapour
2) vapour is injected into fractionating tower
3) molecules with high BP condense straight away (forms bitumen)
4) remaining molecules pass further up the tower
5) bubble caps are in place to prevent the liquid fraction running back down the column
6) refinery gases are collected at the top
Main fractions obtained from crude oil
Refinery gases Gasoline Kerosene Diesel Fuel oil Bitumen
Refinery gases
Power generation, bottled gas
Gasoline
Used to power cars
Kerosene
Aviation fuel, paraffin for lighting and heating
Diesel
Road diesel and gas oil, used in motor vehicles
Fuel oil
Marine diesel for ships
Bitumen
Used for roads and roofing
What are fractions burnt as
Fuels (release a lot of energy)
Problems with complete combustion
CO2 produced - greenhouse gas
Problem with incomplete combustion
CO produced
Poisonous as it binds to haemoglobin and reduces ability to carry oxygen around our bodies
Problems with nitrogen and oxygen and sulfur
Causes acid rain
What is cracking
Changing the longer chain alkanes into shorter chain alkanes
What does cracking require
A silica catalyst
600-700 degrees to vaporise the large hydrogen molecules
What does cracking produce
Smaller alkanes and alkenes
