Coal. Coal Facts Most abundant fossil fuel –400 year supply 66% of known coal is located in the U.S. U.S. is 2 nd largest consumer of coal –China is 1.

Coal

Coal Facts• Most abundant fossil fuel

– 400 year supply

• 66% of known coal is located in the U.S.

• U.S. is 2nd largest consumer of coal

– China is 1st!

• Most environmentally damaging fossil fuel.

What is coal?

• Readily combustible rock

• Mostly carbon with small amounts of water and sulfur

Swamp

Coal Formation

– Decomposition of ancient swamp plants• Quick burial • Partially decayed due to anaerobic conditions (some

carbon remains)

– Intense heat & pressure “cooked” remains

– Time – millions of years to form

Formation of Coal

PEATPEAT

LIGNITELIGNITE

garnero101.asu.edu/glg101/Lectures/L37.ppt

BITUMINOUSBITUMINOUS

ANTHRACITEANTHRACITE

garnero101.asu.edu/glg101/Lectures/L37.ppt

Grades of CoalGrades of Coal• Lignite (brown coal)

– Low quality– 4,000 BTU/lb

• Bituminous (soft coal)– Most common– 8,300 – 10,500 BTU/lb

• Anthracite (hard coal)– Highest carbon content – 98%

• (hottest burning)

– Lowest sulfur content– 14,000 BTU/lb

www.uvawise.edu/philosophy/Hist%20295/ Powerpoint%5CCoal.ppt

• The longer it’s been forming, the higher the grade

– Carbon content increases

– Burns hotter & cleaner!

World Coal Deposits – Most abundant where?

U.S. Coal Deposits

Extracting Coal: Surface Mining

-for coal that is buried less than 200 feet deep

- cheaper

• Mountaintop mining

Pictures: http://www.npr.org/blogs/pictureshow/2009/03/removing_mountains.html

• NPR clip – January 2009

Extracting Coal: Underground Mining

• for coal buried 200-1,000 ft. deep

What is it used for?

• Burned to generate electricity– ½ of electricity in US is from coal

• Making steel– used to smelt iron ore into iron

Environmental Concerns

• Surface mining – removes the top of an entire mountain

• Toxic chemicals – (mercury) leach from waste rock into nearby streams

• Pollution, Acid Rain, & Global Warming – depends on the grade of the coal

• http://www.youtube.com/watch?v=Bk-jrbCi7Sc&feature=related

• Tour through a coal mine• http://www.youtube.com/watch?v=fkHfnp2czZQ

• Centralia, PA

Converting Solid Converting Solid CoalCoal

Changing form is slightly better for pollution, but lessens net E

• Coal gasification Synthetic natural gas (SNG)

• Coal liquefaction Synthetic liquid fuels

• http://www.youtube.com/watch?v=l_K8jXrtPZQ• Sequestration and climate change applications

© Brooks/Cole Publishing Company / ITP

www.bio.miami.edu/beck/esc101/Chapter14&15.ppt

CoalCoal

Cons• Dirtiest fuel, highest carbon dioxide

• Major environmental degradation

• Major threat to health

Pros• Most abundant fossil fuel

• Major U.S. reserves• 300 yrs. at current consumption rates

• High net energy yield