crude oil
Post on 03-Dec-2014
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Crude Oil
Key wordsCrude oilCompoundMixtureDistillationHydrocarbonsSaturatedAlkanesCovalent bondEvaporatingCondenseFractional distillationFractionating columnParticulatesCombustionSootBiofuels
• Microscopic plants and animals die and fall to the sea bed
• Layers of sand and mud form on top
• Pressure and high temperature cause oil to form
How crude oil was formed
• Oil obtained by drilling
Oil is a fossil fuelOther fossils fuels are:
Coal and Gas
Non-renewable Renewable
Biofuels – ethanol and biodiesel made from plants
Crude oil is a mixture of a very large number of compounds.
These compounds can be separated by distillation.
Heated Crude Oil
350oC
40oC
Liquid petroleum gas
Naphtha
Petrol (gasoline)
Paraffin
Diesel
Fuel oil
Lubricating oil
Bitumen
Fraction Boiling pt.
< 25oC
25 – 60oC
60 – 180oC
180 – 220oC
220 – 250oC
250 – 300oC
300 – 350oC
> 350oC
Average number of C atoms in chain
3
8
10
12
20
40
80
120
The Fractional Distillation of Crude Oil
Very hot crude oil is pumped intothe fractionating column where the hydrocarbons separate out by their boiling points, rising through the column until they get cold enough to condense. The compounds that condense at a particular temperature are called a FRACTION.
Properties of the fractions
Most of the compounds in crude oil consist of molecules made up of hydrogen and carbon atoms only (hydrocarbons). Most of these are saturated hydrocarbons called alkanes.
Write the chemical formula for these alkanes
In general:
CH4 C2H6
C3H8
C4H10
CnH2n+2
Alkane molecules can be represented in the following forms:
Fuels
Most alkanes are used as fuels to produce useful forms of energy.
When completely burned alkanes form carbon dioxide and water.
Equations for combustion
CH4
methane
+ O2
oxygen
CO2
carbon dioxide
+ H2O
water
2 2
C3H8 + O2 CO2 + H2O
C2H4 + O2 CO2 + H2O2 2
5 3 4
3
Most fuels, including coal, contain carbon and/or hydrogen and may also contain some sulfur.
The gases released into the atmosphere when a fuel burns may include:•carbon dioxide •water (vapour)•carbon monoxide •sulfur dioxide and •oxides of nitrogen. Solid particles (particulates - sometimes called soot) may also be released.
GLOBAL WARMING
ACID RAIN
GLOBAL DIMMING
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