Organic Chemistry
Fossil Fuels
Fossil Fuels
• Fossil fuels form the major part of our fuel
resources
• They are derived from the fossil remains of
living organisms which have been altered
by heat and pressure
World Proven Reserves of Crude Oil
20.6 65.4
63.7
44.0
675.7
74.9
89.5
thousand million barrels
World Proven Crude Oil Reserves
North America
6%
Middle East
66%
South & Central
America
9%
Europe
2%
Africa
7%
Former Soviet Union
6%
Asia & Pacific
4%
as percent of 1296 thousand million barrel total
Natural Gas
• Formed in large deposits under the sea,
usually together with petroleum
• 90% methane and needs very little
treatment before use.
• Used mainly for heating houses and energy
production
• Piped from the deposit to the land
Coal
• Vast deposits of coal in the Latrobe Valley
Victoria are used to produce electricity.
Oil
• Crude oil is the petroleum that is pumped
directly from the ground.
– It is a complex mixture of hydrocarbons with
one or two carbon atoms up to a limit of about
50 carbon atoms.
– This is usually not useful, so it must separated
by distillation.
• Crude Oil
• This is a main part of this section due to it being used
widely, all over the world, however is a non-renewable
source. It is a mixture of chemicals that are not chemically
bonded (hence it is a mixture), but are still together.
• A hydrocarbon - A molecule that contains only hydrogen
and carbon
• Alkane - A saturated hydrocarbon
• Mixture - More than one substance chemically bonded
• Crude oil from the ground is separated into usable groups of
hydrocarbons at this refinery. Each petroleum product has a
boiling point range, or "cut," of distilled vapors that collect
in condensing towers.
Petroleum
• Petroleum is a mixture of alkanes,
cycloalkanes, and aromatic hydrocarbons.
– Petroleum is formed from the slow decomposition
of buried marine life, primarily plankton and algae.
• As petroleum is formed it is forced through
porous rock until it reaches an impervious
layer of rock.
– Here it forms an accumulation of petroleum and
saturated the porous rock creating an oil field.
Petroleum
• Petroleum was once used for medicinal
purposes.
– It was first distilled by running through a
whiskey still, in an attempt to make it taste
better.
– The liquid that he obtained burned quite well in
lamps.
– This clear liquid that was obtained from
petroleum distillation was called kerosene.
• Crude oil is a mixture of many different
hyrocarbon lengths and we can use
fractional distillation to separate them into
their separate lengths for their unique uses.
The hydrocarbons in crude oil with longer
lengths (more carbon atoms) are more
viscous and therefore have higher boiling
points. This factor means that using the
fractions boiling points, the fractionating
column can separate out the crude oil
according to the different temperatures it
boils.
• The process is as follows:
• Crude oil is pumped into the distillary vapourised
– It enters the column at 340 degrees celcius where the bitumen or
residue which is the most viscous condenses, coming out of the
bottom
– Oil then condenses slighly higher up the tower at 340 degrees
celcius. It has a 35 molecule length and is fractioned off away from
the rest of the mixture
– Next, diesel condenses at 250 degrees celcius with its 20 molecule
length where it is filtered out
– Kerosene at 180 degrees celcius condenses and is sectioned off
with its 15 molecule length
– Naptha is next to condense at 110 degrees celcius with 10
molecules in it's chain
– Petrol at 40 degrees is sectioned off with 8 molecules
– Finally, refinery gas is sectioned off at the top of the tower with it's
3 molecules. This short molecule length is what makes it a gas.
• Petroleum
products and
the ranges of
hydrocarbons
in each
product.
Composition of Crude Oil
CRUDE OIL
HYDROCARBONS
ALIPHATICS
25%
C1 - C60
AROMATICS
17%
(C6H5)n
NON-HYDROCARBONS
NAPHTHENES
50%
CYCLOALKANES
SULFURS
<8%
NITROGENS
<1%
OXYGENS
<3%
<100PPM
O
SH
N
H
S
METALLICS
COOH
The Uses of Crude Oil
Uses of Crude Oil
Uses of Crude Oil
Gasoline
Kerosene Jet Fuel
Gasoline
Liquefied Refinery Gases
Kerosene
Jet Fuel
Coke
Liquefied Refinery Gases
Coke PETROCHEM ICAL FEEDSTOCKS
Kerosene
PETROCHEMICAL
FEEDSTOCKS
Kerosene
Distillate Fuel Oil
Residual Fuel Oil
Distillate
Fuel Oil
Still Gas
Residual Fuel Oil
Asphalt and Road Oil
Still
Gas
Lubricants
Asphalt and Road Oil
Other
Lubricants
Other
CRUDE
Petroleum delivered from well field
DESALTING
Water washing to remove impurities
Distillation to separate by boiling point ranges
REFINING
REFORMING
Conversion reactions to alter molecular structures
BLENDING
Mixing to obtain maximum commercial
characteristics
Petroleum Refining
GAS
CRUDE
DESALTER
FURNACE
T
O
W
E
R
C1-C4
bp < 50 oF
C5 - C?
LIGHT NAPHTHA
bp 50-200oF
HEAVY NAPHTHA
KEROSENE
ATM. GAS OIL
RESIDUUM
C? - C12
bp 200-400oF
C12 - C16
bp 400-500oF
C15 - C18
bp 500-650oC
> C20
bp >650oF
Distillation – separation by boiling point
Petroleum Reforming
FUEL GAS
GAS
T
O
W
E
R
LIGHT NAPHTHA
TREATER
GASOLINE
HEAVY NAPHTHA
KEROSENE
ATM. GAS OIL
REFORMER
HYDROTREATER
AROMATIC
EXTRACTION
AROMATICS
JET FUELS/KEROSENE
HYDROTREATER
HYDROTREATER
CATALYTIC
CRACKER
DIESEL & FUEL OILS
RESIDUUM
VACUUM GAS OIL
Vacuum
Distillation
CATALYTIC
CRACKER
LUBRICATING OIL
ASPHALT
COKER
COKE
Conversion Reactions
THERMAL
CRACK
C7H15.C15H30.C7H15
C7H16 +
gasoline
C7H14 +
C15H30
gasoline additive
recycle
CATALYTIC
ALKYLATION
CH3CH2CH3
CH2 CH
CH3CH2CH2
CH2 CH3
CH2CH2CH2CH3
COMBINE
82%
POLYMERIZATION
H3C
C
CH2 H3C
CH3
REFORMIING
C
CH2
H3C
CH3
C
18%
H
CH3
CH2
CH3
C
CH3
CH2
CH3
Dehydrogenation
Dehydroisomerization
REARRANGE
Isomerization
ISOMERIZATION
Dehydrocyclization
Hydrocracking
H3C
C
CH
CH3
C
CH3
CH3
Catalytic Reforming – Conversion Reactions
Dehydrogenation of cycloalkanes to aromatics
CH3
CH3
3H2
Dehydroisomerization of cyclopentanes to aromatics
CH3
3H2
Isomerization of alkanes
CH3
CH3CH2CH2CH2CH3
Dehdrocyclization of alkanes
H3C CH CH2 CH3
CH3
CH3CH2CH2CH2CH2CH2CH3
4 H2
Hydrocracking of alkanes
CH3CH2CH2CH2CH2CH2CH3
CH3CH2CH3
CH3CH2CH2CH3
Refining Crude Oil
Review
• Complete the revision questions page 188
(40 – 43)
• Complete the revision questions page 190
(44 – 46)
• Complete the multiple choice questions
pages 191 – 192
• Complete the review questions 2, 3, 4, 7, 8,
10, 11, 13, 15, 17, 18
• Complete the exam practice questions