Transcript Fossil Fuels: Types and Use

Fossil Fuels: Types
and Use
Outline
Origins and Types
 Exploration and Development
 Production
 Use
 The Environment

Photosynthesis
Radiant energy
 Chlorophyll, turning sunlight into
carbohydrates.
 Combines radiant energy, CO2 and
H2O, and produces O2 and
carbohydrates.
 Carbon and Oxygen cycles.
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Fossil Fuel Origins
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The organic (carbon-based) remnants of
ancient life.
 Anaerobic bacteria: Bacteria that thrive
where there is NO Oxygen broke down the
remains into molecules of hydrocarbons of
various sizes.
 Overburden: Pressure and heat from the
sediment and rock above the deposits helped
the process of refining the material into fuel.
Coal

There are various types of coal that
reflect the long process by which it is
made.
– Peat – compressed dead leaves in bogs.
– Lignite – dirty, brown coal, can still see bits
of leaves.
– Bituminous and Sub-bituminous.
– Anthracite – the oldest, hardest, cleanest
coal.
Carbon-based fuels
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Hydrocarbons: molecules of carbon and
hydrogen, mostly carbon.
Anthracite is nearly 90% carbon atoms –
Lignite, less than 50%.
Natural Gas, made of methane (CH4), has a
relatively low carbon content.
A “clean” burn of such fuels produces CO2
and H2O (Carbon dioxide and water).
Contributes to the “Greenhouse” effect.
Trace Elements in Fossil fuels
Carbon and hydrogen aren’t alone.
 Coal and oil contain up to 2% Sulfur.
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– Produces Sulfur dioxide, SO2, upon burning,
leading to acid rain.
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Other non-combustible materials producing
ash or soot – particulates.
 Coal even has uranium in it, the stuff of atom
bombs.
– Presently, more radioactive materials are
introduced into the environment by the burning of
coal than by nuclear power production.
Fossil fuel deposits
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Coal lies in great beds usually just under the surface.
Oil and Natural Gas are typically found where the
rock above has formed a natural cap, or dome.
– Geologic entrapment.
Fossil Fuel Exploration and
Recovery
Use Seismic data to map the underground –
looking for domes of rock that might hold oil
and gas.
 Drilling
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– Exploratory wells -- 1 in 9 is successful in US.
– Primary recovery – natural pressure – 15% of
deposit.
– Secondary recovery – pump water or gas to force
oil out – 15% more.
– Tertiary recovery – techniques to reduce viscosity
and surface tension – 10%
Methods of Further Refining
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Coal can be further
processed to obtain
synthetic liquid or
gas fuels.
 Natural Gas can be
compressed into a
liquid.
 Oil is refined into
numerous different
products.
Cooling and
Condensing
As it rises…
Gasoline Additives
Lead – enhances “octane” rating.
 MTBE – an oxygenate to reduce
Carbon monoxide emissions – now
suspected of being a carcinogen.
 Ethanol – corn or sugar cane turned into
alcohol to improve octane, make the
fuel cleaner, make the farmers happy.
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Natural Gas – the next big thing.
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Natural gas burns cleaner.
 Less carbon per weight.
 New turbine designs use the natural gas to
run a turbine, and then heat up water to run a
traditional steam generator – Efficiencies of
45% or more.
 Natural gas is cheaper 3.5 to 1 compared to
coal, 1.75 to 1 compared to gasoline.
Outlook
Still the easiest and cheapest fuel
around.
 Technologies are being developed to
increase yields, enhance efficiency and
reduce pollution.
 The biggest obstacles remain that they
are non-renewable, carbon-based
resources.
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