Post on 18-Jan-2016
transcript
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
63.7
89.5
20.6
74.9
65.4
44.0675.7
thousand million barrels
World Proven Crude Oil Reserves
Europe2%
North America 6%
South & Central America
9%
Middle East66%
Asia & Pacific4%
Former Soviet Union6%
Africa7%
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 NON-HYDROCARBONS
ALIPHATICS AROMATICS NAPHTHENES SULFURS NITROGENS OXYGENS METALLICS
25% 17% 50% <8% <1% <3% <100PPM
C1 - C60 (C6H5)n CYCLOALKANESSH
S
NH
O
COOH
The Uses of Crude Oil
Uses of Crude Oil
Gasoline Distillate Fuel Oil
Kerosene J et Fuel Residual Fuel Oil
Liquefied Refinery Gases Still Gas
Coke Asphalt and Road Oil
PETROCHEMICAL FEEDSTOCKS Lubricants
Kerosene Other
Uses of Crude Oil
Gasoline Distillate Fuel OilKerosene Jet Fuel Residual Fuel OilLiquefied Refinery Gases Still GasCoke Asphalt and Road OilPETROCHEMICAL FEEDSTOCKS LubricantsKerosene Other
CRUDE
DESALTING
REFINING
REFORMING
BLENDING
Distillation to separate by boiling point ranges
Water washing to remove impurities
Conversion reactions to alter molecular structures
Mixing to obtain maximum commercial characteristics
Petroleum delivered from well field
Petroleum Refining
GAS
LIGHT NAPHTHA
HEAVY NAPHTHA
KEROSENE
ATM. GAS OIL
RESIDUUM
CRUDE DESALTER FURNACE
C1-C4
bp < 50 oF
C5 - C?
bp 50-200oF
C? - C12
bp 200-400oF
C12 - C16
bp 400-500oF
C15 - C18
bp 500-650oC
> C20
bp >650oF
TOWER
Distillation – separation by boiling point
Petroleum ReformingGAS
LIGHT NAPHTHA
HEAVY NAPHTHA
KEROSENE
ATM. GAS OIL
RESIDUUM
TOWER
FUEL GAS
TREATER
HYDROTREATER
HYDROTREATER
HYDROTREATER
REFORMER AROMATIC EXTRACTION
CATALYTICCRACKER
JET FUELS/KEROSENE
DIESEL & FUEL OILS
GASOLINE
AROMATICS
VacuumDistillation
VACUUM GAS OIL
LUBRICATING OIL
COKER COKE
ASPHALT
CATALYTICCRACKER
Conversion Reactions
gasoline gasoline additive recycle
C7H15.C15H30.C7H15 C7H16 + C7H14 + C15H30CRACK
COMBINE
REARRANGE
THERMAL
CATALYTIC
ALKYLATION
POLYMERIZATION
REFORMIING
ISOMERIZATION
CH3CH2CH3 CH2 CH CH2 CH3CH3CH2CH2 CH2CH2CH2CH3
C H3C
CH3
CH2C H3C
CH3
CH2C H3C
CH3
CH3
C CH2
CH3
H
CH2C CHCH3
CH3CH3
CH3
H3CC
82% 18%
Dehydrogenation
Dehydroisomerization
Isomerization
Dehydrocyclization
Hydrocracking
Catalytic Reforming – Conversion ReactionsDehydrogenation of cycloalkanes to aromatics
Dehydroisomerization of cyclopentanes to aromatics
Isomerization of alkanes
Dehdrocyclization of alkanes
Hydrocracking of alkanes
CH3 CH3
3H2
CH3
3H2
CH3CH2CH2CH2CH3 CHH3C
CH3
CH2 CH3
CH3CH2CH2CH2CH2CH2CH3
CH3
4 H2
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