M11-P1 Materials from
the Earth
6th International Junior
Science Olympiad (IJSO)
Dr. Yu-San Cheung
yscheung@cuhk.edu.hk
Department of Chemistry
The Chinese University of Hong Kong
1
Natural Resources(天然資源)
•
•
•
•
Naturally occurring substances
Considered valuable in their relatively unmodified (natural) forms
Values: depending on the amount available and the demand
A commodity is generally considered a natural resource when the
primary activities associated with it are extraction and purification,
as opposed to creation.
• Examples of natural resources:
Air, water, and soil
Biological resources - plants and animals
Raw materials (like minerals)
Space and land
Energy (like wind, geothermal(地熱的), tidal(潮汐的), and
solar energy)
http://en.wikipedia.org/wiki/Natural_resources
http://www.ecofriendlykids.co.uk/NaturalResourcesEarth.html
2
Renewable Resources(再生資源)
• They can restock (renew) themselves, be used indefinitely if
they are not over-harvested.
• If consumed at a rate that exceeds their natural rate of
replacement, the standing stock will diminish and eventually
run out.
• Examples of living renewable resources:
• trees (forests and woodlands) and crops
• fish and livestock
• Examples of non-living renewable resources:
• fresh water
• fresh air
• Flow renewable resources (or simply “flow resources”):
renewable, but needing no regeneration or re-growth
e.g., wind, tidal, and solar energy
http://en.wikipedia.org/wiki/Natural_resources
http://www.ecofriendlykids.co.uk/NaturalResourcesEarth.html
3
Non-renewable Resources (非再生資
• A non-renewable resource is a natural resource that cannot be
re-made, re-grown, or regenerated on a scale comparative to
its consumption.
• Fossil fuels, such as coal, petroleum, and natural gas are often
considered non-renewable resources, as they do not naturally
re-form at a rate that makes the way we use them sustainable.
4
http://en.wikipedia.org/wiki/Natural_resources
Natural Resources and Their
Products
• Forests: timber (for building houses, boats, decks, and furniture;
and making paper)
• Mines: metal products, fossil fuels, salts, jewelry, gravel (for
building roads and concrete)
• Aquaculture(水產養殖): fishes, shrimps, crabs, etc.
5
http://www3.iptv.org/exploremore/land/issues/iss_natu/natural_resources.cfm
Minerals and Their Chemical
Components
Exercise:
Find out the major chemical content in various types of
minerals
6
“Periodic Chart.pdf” in http://www.mii.org/
Common Minerals and Their Uses
Exercise:
Find out the uses of some common minerals.
7
http://www.mii.org/commonminerals.html
Cement & Concrete
Cement: 水泥
Concrete:混凝土
Cement:
• made from limestone, calcium, silicon, iron, and aluminum, plus
lesser amounts of other ingredients
• When water is added to cement, a chemical process occurs as it
dries, allowing it to harden.
Concrete:
• cement + aggregates (e.g., sand, stone)
• Important and widely-used construction material
• Strengthened by steel-rod skeleton
• Annual production: about 6 billion tons
(~1 ton each person on the Earth)
• Life: 50,000 years
8
http://www.wisegeek.com/what-is-the-difference-between-concrete-and-cement.htm
Recycling(循環)
Recycling is the reprocessing of materials into new products.
It can save energy and reduce air pollution.
Exercise:
Find out the environmental effects of recycling.
http://en.wikipedia.org/wiki/Recycling
9
Recycling (循環)
•
•
•
•
•
•
•
•
•
•
•
Aggregates and concrete
Crushed and used as aggregates for new concrete
Batteries
Difficulty: so many types of batteries
Some old types contain mercury and cadmium
Lead-acid battery (mostly used in automobiles): containing lead
Biodegradable waste
Electronics waste (recovering metals)
Various types of metals (e.g., _________________________________)
Paper
Glass
Plastic
Rubber
Textiles
Timber
10
http://en.wikipedia.org/wiki/Recycling
Metals
In chemistry:
• A metal is an element that readily loses electrons to form positive
ions (cations) and the cations are surrounded by a sea of
electrons
• Most metals form ionic bonds with non-metals [but not always,
e.g., in Pb(C2H5)4, there is Pb–CH2CH3 covalent bond]
Physical properties:
• Electrical conducting
• Some hard, some soft, some being liquid


+

+

+

+
+
11
http://en.wikipedia.org/wiki/Metal
Alloys(合金)
• Alloy: a homogeneous mixture of two or more elements, at least
one of the elements is a metal, the resulting mixture has metallic
properties.
• An alloy usually has properties (physical and chemical) different
from those of its components.
Example
The major component of steel is iron and steel is stronger than
iron.
If chromium is added, we have stainless steel which can resist
corrosion.
12
http://en.wikipedia.org/wiki/Alloy
Examples of Alloys
•
•
•
Carbon steel:
iron + carbon (higher carbon content, stronger but more brittle)
Low carbon steel: ~0.05 – 0.3% carbon content
Ultra-high carbon steel : ~1 – 2% carbon content
Stainless steel: steel + chromium (> 10%)
Brass: copper + zinc (typically ~30 – 35%)
•
Bronze: copper + tin (typically 12%)
•
Rose gold: gold + copper: for jewelry
24k: 100% gold (18k: 75% gold) (k = “karat”)
•
Solder:
Conventional: Sn60/Pb40 (60% tin + 40% lead)
Lead-free: e.g., SnAgCu (tin + silver + copper);
different SnAgCu compositions: different melting points
http://en.wikipedia.org/wiki/Carbon_steel
http://en.wikipedia.org/wiki/Stainless_steel
http://en.wikipedia.org/wiki/Brass
http://en.wikipedia.org/wiki/Bronzes
http://en.wikipedia.org/wiki/Rose_gold
13
http://en.wikipedia.org/wiki/Solder
http://en.wikipedia.org/wiki/List_of_alloys
Energy Resources
• Solar energy
• Wind energy
• Water-related:
•
•
•
•
•
hydro power
pumped-storage
tidal power
wave power
Geothermal energy
Biomass energy
Garbage energy
Nuclear energy
Fossil fuels
14
http://home.clara.net/darvill/altenerg/index.htm
Generation of Electrical
Energy(電能)
• Electrical energy is easily transported (from power plants to
individual customers)
• Electrical energy is versatile
• Majority of energy available from Nature: in the form of kinetic
energy and heat energy
• Kinetic energy  electrical energy
• Heat energy  kinetic energy of steam  kinetic energy of
magnet/metal  electrical energy
15
Faraday‘s Law(法拉第定律) of
Induction
• In effect:
Changing magnetic field  electrical current
http://hyperphysics.phy-astr.gsu.edu /Hbase/electric/farlaw.html
• That is, kinetic energy  electrical energy
16
Turbine(渦輪機)
• Flow of fluid (acting on blazes)  rotation of shaft
• Kinetic energy of fluid  kinetic energy of shaft  electrical
energy
17
http://en.wikipedia.org/wiki/Turbine
Solar Energy(太陽能)
• Energy from the Sun
• The Sun is a nuclear reactor, 150 million km away. Only a small
fraction of light energy and heat energy (1 part in 1010) reaches
the Earth, but it is a huge amount to the Earth.
Increasing wavelength
Ultra-violet(UV)
“light”
Visible
Infra-red (IR)
Absorbed and becoming heat energy
• Solar cell: light energy  electrical energy
• Water-heating system:
heat energy  heat energy of water
• Solar furnaces:
heat energy  heat energy of gas  kinetic energy of gas 
electrical energy
http://home.clara.net/darvill/altenerg/solar.htm
18
Exercise:
How is solar energy used for heating water in Hong Kong?
Example:
http://www.cuhk.edu.hk/greencampus/en/communication/sc_sp
ring07.pdf
19
Wind Energy(風能)
• Energy from wind
• Ancient application: sailing
• Used since Middle Ages: windmill
• Electricity generation:
wind  turbine  electricity
(reverse of electric fan operation)
Propeller blades
Wind
Gearbox & generator in
housing which can be rotated
to face the wind
Tower
20
http://home.clara.net/darvill/altenerg/index.htm
Hydro Power(水力)
• Energy from the flow of water:
(potential energy of water  kinetic energy of water  …)
• Ancient application: corn grinding, sailing, war
• Used nowadays to generate 20% of the world’s electricity
Dam
Reservoir
Turbine
Generator
21
http://home.clara.net/darvill/altenerg/index.htm
Pumped Storage Reservoirs
• They are not facilities or methods to generate electrical power.
They are a way of storing energy so that it can be released
quickly when needed.
• Demand for electrical power changes throughout the day.
When the demand is low, extra power not used is wasted.
• A facility is needed
which can store
excess energy
produced, and can
release the stored
energy immediately.
Pumped storage
reservoirs can do the
job.
Turbines
& Pumps
Top
Reservoir
Lower
Reservoir
22
http://home.clara.net/darvill/altenerg/index.htm
Tidal Power(潮汐能)
• Tide: water movement, containing kinetic energy
• Twice a day
• 8 sites in Britain, generating
20% of energy needed
• ~20 potential sites in the world
• Largest one: northern France
Tide coming in
Tide going out
23
http://home.clara.net/darvill/altenerg/index.htm
Off-shore Station
http://www.swanturbines.co.uk/
http://www.marineturbines.com/technical.htm
24
Wave Power
• Wave: generated by wind on sea surface
• Method: reverse of a swimming pool wave machine
Air flowing in and out
Water level going
up and down
25
http://home.clara.net/darvill/altenerg/wave.htm
Geothermal Energy(地熱能)
• The centre of the Earth: ~6000 C
hot enough to melt rock
• A few km down the surface: > 250 C
• Used for thousands of years in some countries for cooking and
heating
• If hot enough to
produce steam 
electricity
• If not: heating
Power station
Cold
water
down
Hot
water
down
Hot region
26
http://home.clara.net/darvill/altenerg/geothermal.htm
Biomass(生物量)
• Energy from organisms (usually plants)
• Example: burning of wood for heat and light
• Extraction of fuel: ethanol by fermentation:
corns / canes  cane sugar  ethanol
• Biodiesel: a fuel made from vegetable oil that runs in any
unmodified diesel engine.
Triglycerides (三酸甘油酯)
(Esters of glycerol with long-chain fatty acids)
27
Triglycerides  Biodiesel
NaOH
+
CH3OH
Glycerol
Glycerol part Fatty acid portions
Methyl
esters of
fatty acid
(Biodiesel)
28
Biodiesel
Recipe: Biodiesel from New Oil
http://www.dancingrabbit.org/biodiesel/newoil.php
Use of Biodiesel in automobiles
Example:
1994 Dodge:
100,000 miles on 100% Rapeseed (芥花籽)
29
Garbage Energy
• Burning garbage: generating heat energy, but serious
pollution (e.g., dioxin)
• Bacterial action: generating landfill gas (mainly methane,
CH4)
30
Basis of Nuclear Physics
& Nuclear Power
31
Testing your knowledge on:
molecules, atoms, and subatomic particles
• A molecule consists of two or more _____ of the same or
different elements.
Examples: ____________________________
• Atoms are the smallest particles of an element.
• Sub-atomic particles: particles that constitute atoms.
___________
___________
___________
Which of these sub-atomic particles make up nuclei?
32
Testing your knowledge on:
molecules, atoms, and subatomic particles
Compare the sizes of:
molecules, atoms, and nuclei.
Exercise (fill-in-the-blank):
Isotopes are atoms of the same _______ but having different
numbers of ________ in their ________.
33
Nuclides(核素)
A nuclear species characterized by specific values of the
atomic number (no. of protons) and the mass number (no. of
protons and neutrons)
1
1H
2
1H
12
6C
13
6C
34
Radioactive(放射性)Substances
Nuclei of some atoms, e.g., 40K, are unstable. They undergo
spontaneous transformation into more stable atoms. The
substance is called radioactive.
Such a transformation process is called radioactive decay. It is
usually accompanied by emitting particles and energy collectively
called radiation.
35
Radioactivity(放射現象)
The phenomena of radioactivity was discovered in 1896. This
radiation was later shown to be separable by electric (or
magnetic) fields into three types: alpha (a), beta (b) and
gamma (g) rays.
Radioactive material
b ray
Electric plate (positive)
+
–
g ray
a ray
Lead block
Electric plate (negative)
Luminescent screen
36
Stability of Nuclides(核穩定性)
• Unstable nuclei are radioactive
• Nuclei consist of proton(s) & neutron(s)
(except __________)
• Forces inside the nuclei:
(1) Repulsive Coulomb force: between protons
(2) Attractive nuclear force: between proton & proton,
neutron & neutron, proton & neutron
• Stability depends on the balance of the two forces
37
Radioactive Decay Products
• Alpha particle (helium-4 nucleus, 4He2+)
• Beta particle (electron)
• Gamma ray / X-ray (electromagnetic radiation)
• Neutron
38
Interaction of Radiation with Cells
• Ionization and atomic excitation causing molecular
rearrangement or formation of free radicals
• Alteration of molecules leads to malfunction of
physiological processes which depend on the
chemical structure
Examples:
inhibition of cell division, denature of enzymes, mutation of
genetic materials
39
Rate of Radioactive Decay
• Half-life (t1/2): the time it takes for half of its original amount
to decay
1  ½  ¼  1/8
 1/16 ….
After n half-lives,
is
left.
For example, after 10 halflives,
1/(210) = 1/1024 (about
0.1%) is left.
1/(2n)
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0
10
20
30
40
50
60
70
80
90
100
40
Half-lives of Some Radionuclides
Each radionuclide has a characteristic t1/2
Radionuclide
81Kr
38K
73Se
131I
60Co
137Cs
14C
129I
235U
40K
Half-life
13 seconds
7.6 min
7.2 hr
8 days
5.3 yr
30 yr
5730 yr
17 million yr
703 million yr
1260 million yr
41
Sources of Radiation
Natural Radiation
• cosmic rays
• terrestrial radiation (including radon)
• food & drinks (40K within body)
Artificial Radiation
•
•
•
•
medical instruments
leakage/disposal
radioactive fallout (weapon testing)
consumer products, e.g., smoke detectors, “glow in
the dark” watches
42
Nuclear Fuel(核燃料)
235U
+n
139Ba
+
94Kr
Ba
+ 3n
n
U
235
Characteristics:
n
• Bombarded by neutron
Kr
• Chain reaction:
Ba
n
an
U
235
This neutron
starts the chain Kr
reaction
But not every neutron can hit
235U
Ba
n
1 neutron in,
3 neutrons out.
n
nucleus.
The reaction may eventually stop.
n
n
U
235
n
n
n
Kr
Ba
n
U
235
n
n
Kr
http://home.att.net/~cat4a/nuclear_III.htm
43
Enriched Nuclear Fuel(核燃料)
To make the chain reaction self-sustaining,
we need to use:
(1) uranium enriched in
235U
(2) super critical mass of the fuel
Natural uranium:
238U
Enriched: 2-3% in
(99.3%) &
235U
235U
(0.7%)
(>85% for bomb)
Methods: centrifugation, diffusion,
and electromagnetic isotopic separation.
44
Critical Mass(臨界質量)
Critical mass: sphere of 600 kg for 15%
Higher
235U
235U
(~40 cm diameter)
percentage: larger/smaller critical mass
Neutron reflector: larger/smaller critical mass
45
http://en.wikipedia.org/wiki/Image:Critical_mass.svg
Nuclear Power Plant(核能發電廠)
http://science.howstuffworks.com/nuclear-power2.htm
Containment Structure
Steam Generator
Steam Line
Reactor
Turbine
Control
Rods
Generator
Cooling Tower
Pumps
Cooling Water
Condensor
Neutron absorber
(e.g., boron, cadmium)
46
http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/control.html
Other Nuclear Fuels
Plutonium-239 & Uranium-233
47
Nuclear Fusion(核聚變)
Heavy nuclei favor fission.
Light nuclei favor fusion.
Examples of nuclear fusions:
2H
+ 3H  4He + n
2H
+ 2H  3He + n
2H
+ 2H  3H + p
48
http://en.wikipedia.org/wiki/Nuclear_fusion
Human-made Nuclear Fusion
In order for a nuclear fusion to occur, two nuclei must be brought
close enough.
But the repulsion between nuclei is huge.
Nuclei must contain high enough energy.
Human-made nuclear fusion:
through nuclear fission in nuclear bomb
49
Nuclear Fusion(核聚變)
in Nuclear Power Plant
Nuclear fusion: more energy released than fission
But …
once started, nuclear fusion is out of controlled and cannot be
stopped.
Nuclear fusion for power generation: to be developed.
Other advantages of fusions over fissions:
• less hazardous products
• source more available (natural abundance of 2H: 0.015%)
50
Accidents of Nuclear Power Plants
• Three Mile Island, USA (1979)
• Chernobyl, Ukraine, in former USSR (1986)
Leakage of highly radioactive materials
On the whole, non-nuclear large-scale industrial accidents result in
higher tolls.
51
Nuclear Weapons &
Nuclear Power Plants
A nuclear power plant does not aim to make nuclear weapons.
But the materials can be used for nuclear weapons.
Concerns:
• 235U: needs extra work to enrich its percentage
• 329Pu: created in a uranium reactor, the percentage of which is
high enough for nuclear weapons
In addition to making a nuclear bomb (which can really explode),
the waste can also used for “dirty bomb”.
More about nuclear proliferation:
http://en.wikipedia.org/wiki/Nuclear_proliferation
52
Advantages & Disadvantages
Advantages
• No CO2 is emitted
• No air is needed
Disadvantages
• In case of accident, the damage is serious
• Using and producing materials, which are the source for
nuclear weapons
• Disposal of nuclear waste: waste cannot be “destroyed”
53
Fossil Fuels(化石燃料)
Industrial Revolution:
increases in the use of fossil fuels
Steam engines (late 1700s): needed fuels
chemical energy (stored in _______) 
heat energy (of _______) 
kinetic energy (of _______) 
kinetic energy (of _______)
to run machines, cars, etc.
54
What are fossil fuels?
Plants, animals, and microorganisms (living millions of years ago)
 death
Remains buried and subjected to high temperatures and
pressures in Earth’s crust
Primarily hydrocarbons, CxHy
“Fossil fuel” sometimes also includes non-biological source such
as tar sand, which is known as mineral fuel.
55
Types of Fossil Fuels(化石燃料)
•
•
•
•
•
Coal
Petroleum (oil)
Natural gas
Tar sands and oil shale
Methane hydrate
56
Carbon Cycle
Exercise:
Find out the carbon distribution in the Nature from internet.
Atmosphere (
Vegetation (
Soils (
)
)
Fossil Fuels & Cement
Production (
)
)
Marine Biota (
)
Surface Ocean (
)
Deep Ocean (
Dissolved Organic Carbon
(
)
Sediments (
)
)
57
http://en.wikipedia.org/wiki/Image:Carbon_cycle_diagram.jpg
Heat Energy Units
• BTU (British Thermal Units) = 1054 – 1060 J
• Quad: quadrillion BTU = 1015 BTU
• Total U.S. energy use: ~100 Quad in 2005
• A barrel of oil (bbl): ~6 million BTU
• 100 Quads: 17 billion barrels of oil
(1 bbl = 42 gallons)
http://en.wikipedia.org/wiki/British_thermal_unit
http://www.opm.state.ct.us/pdpd2/energy/flows94.htm
58
Coals(煤)
•
•
•
•
Plant remains covered by water and mud
Readily combustible
Black or brownish black in color
Mainly composing of carbon, with an assortment of other
elements (e.g., sulfur)
Most abundant of all fossil fuels, the largest single source of fuel
for the generation of electricity world-wide
One of the major sources of carbon dioxide emissions
59
http://en.wikipedia.org/wiki/Coal
Worldwide Coal Production
Exercise:
Find out the worldwide coal production, coal reserves, and major
coal exporters.
60
Processing of Coal
Other than being burnt directly, coal can be further processed to
obtain higher-quality fuel.
• Liquefaction: coal  liquid fuels
e.g., gasoline or diesel
• Gasification: C + steam + O2  synthesis gas (CO + H2)
• Coking (~ 1000 oC): driving off volatile substances to form coke
61
Petroleum(石油)(Oil, Crude Oil)
• Compression and heating of ancient organisms
• Buried at the ocean bottom, where O2 was insufficient
to oxidize all the organic materials
62
Oil Producing and Consuming
Countries
Exercise:
Find out the major oil producing and consuming countries
around the world.
63
Petroleum(石油)
• Hydrocarbon, mostly alkane (saturated CxHy): C5H12 to C18H38
Shorter hydrocarbon: natural gas
Longer hydrocarbon: paraffin wax
• High energy density, easy transportability, relatively high
abundance
• Source of raw material for many chemical products
64
Oil Refinery: Separating Components of
Different Molecular Weights
Exercise:
Find out various oil
refinery products and
their usages.
Very detailed flowchart:
http://en.wikipedia.org/wik
i/Image:RefineryFlow.png
65
http://en.wikipedia.org/wiki/Oil_refinery
Cracking(裂解)
• Breaking down long carbon chains
• By heating & with catalysts
• e.g. CH3CH2CH2CH3 
CH2=CH2 + CH3CH3
66
Knocking of Gasoline(汽油)
• Gasoline is burnt to produce energy in a combustion engine
(e.g., of a vehicle)
• Some gasoline start to burn before they are ignited by sparks.
• This premature ignition produces a “knocking” sound. So it is
sometimes called “knocking”.
• Consequences of knocking:
power loss and engine wearing
67
http://en.wikipedia.org/wiki/Octane_rating
Octane Rating
• Different gasoline have different anti-detonation
• Octane rating: a measure of the anti-detonation (or autoignition resistance) of gasoline and other fuels used in
spark-ignition internal combustion engines.
68
http://en.wikipedia.org/wiki/Octane_rating
Octane Rating
iso-octane: set at 100
n-heptane: set at 0
A mixture of iso-octane and n-heptane:
x% (by volume) in iso-octane, “octane rating”: x.
Example:
84 liters of iso-octane + 16 liters of n-heptane
84% (by volume) in iso-octane
16% (by volume) in n-heptane
Octane Rating: 84
It is found that 1-pentene has the same “knocking” property as
this mixture, so we say that the octane rating of 1-pentene is
84.
69
Octane Rating
Octane rating can be smaller than 0 and larger than 100.
e.g.,
n-octane: -10
benzene: 101
ethane: 108
Octane rating for gasoline for vehicles: 85-90.
70
http://en.wikipedia.org/wiki/Image:09-03-06-Octane.jpg
Anti-knocking Agent
Tetra-ethyl lead (TEL):
• Added to gasoline to increase octane rating
• About 0.05% of TEL in gasoline
• Pb(CH2CH3)4, mostly covalent in nature, not containing Pb4+ and
CH2CH3–
How it works:
• Knocking causes formation of radicals, e.g., CH3, from gasoline
• Chain reaction: these radicals destroy other gasoline molecules
• Pb(CH2CH3)4  Pb(CH2CH3)3 + CH2CH3 (or Pb + 4 CH2CH3 ?)
These radicals from TEL and remove radicals from gasoline
Sometime literatures say that Pb + O2  PbO2
and the PbO2 reacts with the radicals from gasoline
Other anti-knocking agents (also called octane enhancers):
methanol & ethanol
71
Problems of Leaded Gasoline
• Lead is toxic to humans
• It poisons Rh and Pt catalysts in catalytic converters (which
convert NOx and VOC emitted from pipes of vehicles into
harmless substances)
Rh = rhodium
Pt = platinum
Both are metals with catalytic property
72
Natural Gas(天然氣)
• Formation process: similar to that of petroleum
• Components: (%)
methane (CH4): 70 – 90
ethane (C2H6): 5 – 15
propane (C3H8), butane (C4H10): < 5
CO2, N2, helium,
and hydrogen sulfide (H2S): balance
Exercise:
Find out the major natural gas producing and consuming
countries around the world.
73
Tar Sand
• Also called “oil sand” (actually more appropriate)
• A mixture of extremely heavy crude oil, sand or clay, and
water.
• Natural material, nothing to do with tar (man-made)
• Worldwide sources:
Canada, Venezuela, and USA.
74
http://en.wikipedia.org/wiki/Tar_Sands
Oil Shale(油頁岩)
• A fine-grained sedimentary rock containing significant traces
of kerogen (a solid mixture of organic chemical compounds)
that have not been buried for sufficient time to produce
conventional fossil fuels.
• When heated to a sufficiently high temperature a vapor is
driven off which can be distilled to yield a petroleum-like
shale oil, a form of non-conventional oil, and combustible
shale gas.
• Can be burnt directly as a low-grade fuel for power
generation and heating.
• Can be used as a raw material in the chemical and
construction materials industries.
• Reserve: mainly in North America
75
http://en.wikipedia.org/wiki/Oil_shale
Methane Hydrate (Methane Ice)
• Ice that contains a large amount of methane within its crystal
structure
• Total amount: 500-2500 billion tons of carbon
(carbon for all fossil fuel reserves: 5000 billion tons)
• Natural gas hydrates (NGH) vs. liquefied natural gas (LNG) in
transportation:
NGH: stable up to −20 C
LNG: stable up to −162 C
Therefore, there is some interest
in converting natural gas into NGH
rather than LNG for transportation.
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http://en.wikipedia.org/wiki/Methane_hydrates