Fossil FuelsFormation, Distribution,

Extraction & Purification, Advantages & Disadvantages,

Alternatives

Fossil Fuels Coal Oil (Petroleum) Natural Gas

Formation of Fossil Fuels – common conditions High Organic Production Burial of organic material Reducing conditions – little or no free oxygen Reducing conditions preserve organic matter Coal and Petroleum diverge from here

Formation of Coal Accumulation of land plant material Reducing conditions – coastal and inland

swamps

Formation of Coal

Organic accumulation is greater than destruction (because of reducing conditions)

Organic matter builds up to form peat

Formation of Coal Peat is compressed to form

lignite – brown coal Lignite is compressed and

volatile compounds are lost to form bituminous coal – soft coal

Bituminous coal is further compressed and heated to form anthracite – hard coal

Formation of Petroleum and Natural Gas

Accumulation of organic material – typically marine mud

Burial and preservation of organic material – reducing conditions

Reducing conditions in deep sea or on continental shelves during times of unusual oceanic circulation

Formation of Petroleum and Natural Gas Black, organic-rich mud is buried deeper and

converted to rock – shale With burial, the organic matter is heated When heat is sufficient (but not too great) – in

the range of 100-300 degrees C – the organic matter is “cooked” and oil forms

Process is called thermal maturation

Formation of Petroleum and Natural Gas If heat is greater than 300 degrees C, the liquid

petroleum is further broken down to form natural gas

If heat is too great, even the natural gas is broken down to form carbon dioxide, which has no value as a fuel

Migration and Concentration Petroleum must leave source rock Process is called migration Migration is essential because most source

rocks are too fine-grained to enable easy extraction of the oil

To be economically concentrated, petroleum must migrate to a reservoir rock with a trap

Examples of Petroleum Traps

Petroleum Resources Conditions for source rock

are rare Conditions for maturation

must be just right Migration must not let

petroleum escape to surface

Reservoir rock must be present

Trap must exist before migration occurs

Where did the U.S. Petroleum Industry begin?

In New York! First gas well –

Fredonia, New York

Distribution of Petroleum Economic accumulations of petroleum only

occur when all of these conditions are met These conditions and the sequence of

occurrence do not occur everywhere Conditions are most likely where there are thick

accumulations of sedimentary rock – in sedimentary basins

Some of the world’s most productive sedimentary basins

Saudi Arabia, Kuwait, Alaska – north slope, Texas – Louisiana Gulf Coast, Iraq and Iran, Mexico, Venezuela

Refining of Petroleum Heat and/or chemical treatment to produce: Gasoline Diesel Fuel Kerosene Liquified Propane (LPG) Petroleum bases for plastics

Fractional Distillation

Advantages Highly compact & portable Source of organic molecules &

sulfur Heat-tolerant lubricant Excellent road & roof surfacing Solvents for paint NG – cooking fuel, fertilizer,

detergents, & helium Very economical Replaced whale oil (saved the

whales) Source of advanced technology

Disadvantages Burning releases most CO2 Nonrenewable - 50 to 150 yr National Security - Source

Countries unstable Transportation – spills & leaks Increasing Consumption vs.

Decreasing Production Oil & NG are a carcinogens Contribute to smog Water Pollutant Land Degradation Sulphur & Nitrogen contributes to

air pollution.

Alternatives to Fossil Fuels

Electricity & Heat Solar Wind Water Geothermal Hydrogen Bio-fuels

Transportation Electricity Biofuels Hydrogen

Plastics Algae Corn Sugar Cane & Sugar Beets

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