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 st ! 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
PEATLIGNITE garnero101.asu.edu/glg101/Lectures/L37. ppt garnero101.asu.edu/glg101/Lectures/L37. ppt
BITUMINOUS ANTHRACITE garnero101.asu.edu/glg101/Lectures/L37. ppt garnero101.asu.edu/glg101/Lectures/L37. ppt
Grades 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 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: /03/removing_mountains.html /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
Tour through a coal mine Centralia, PA
Converting Solid Coal Changing form is slightly better for pollution, but lessens net E Coal gasification Synthetic natural gas (SNG) Coal liquefaction Synthetic liquid fuels Sequestration and climate change applications
© Brooks/Cole Publishing Company / ITP 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