Introduction to Coal

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Introduction to Coal
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What is coal?
http//cleantechnica.com

• The 3 Ps of coal formation
• Plants
• Preservation
• Pressure ( temperature)

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1. PLANTS

• Large amounts of plant material accumulate over
  thousands of years, usually in a swamp. (Peat)

www.fieldmuseum.org
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Smithsonian National Natural History Museums
recreation of coal swamp 300 million years ago
Modern-day swamp of the Mississippi River Delta
http//confluence.org/us/la/n30w090v3/pic8.jpg
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2. PRESERVATION

• Dead plant material is very fragile and decays
  easily in the presence of oxygen.
• Swamp waters are ideal for preservation
• stagnant and low in oxygen
• Organisms that might eat the plants can not live
  in those conditions
• Rivers overflow into swamps
• Bury plant material in sand and mud
• Sea level rises and floods the swamps
• Covers plant material with marine mud

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Plants Preservation

• It takes about 10 ft. of dead plant material to
  produce 1 ft. of coal.
• The conditions of the water and plants must be
  just right for enough organic material to
  accumulate

West Virginia Geological Economic Survey
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3. PRESSURE temperature Coalification How
peat becomes coal

• Dead plant material is compressed from above by
  thick, heavy layers of sediment, slowly turning
  the deposits to solid rock
• As it is buried deeper below the earths surface,
  pressure and temperature increase, removing
  moisture and gases, and changing the proportions
  of the 3 main elements CARBON, OXYGEN, and
  HYDROGEN
• Changes are gradual and occur over millions of
  years

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Coal Classification
Kentucky Geological Survey (2006)http//www.uky.e
du/KGS/coal/coalkinds.htm

• Coal is classified into 4 main ranks based on
  chemical composition and which stage of
  development it is in.
• Peat (precursor to coal) ? Lignite ?
  Sub-bituminous ? Bituminous ? Anthracite

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Coals Components
Coal in Pennsylvania ( 2002)

• Carbon, Hydrogen, Oxygen content are important
  for determining rank
• Coal also contains varying amounts of Nitrogen,
  Sulfur, and mineral particles of clay, quartz and
  calcite (ash)

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Distinguishing among ranks of coal
Data compiled from Penn State Coal Database and
Argonne Premium Coal Sample Program
Anthracite
Bituminous

• How do C and heating value change with rank?

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How does oxygen and hydrogen content vary with
rank?
A
B
A
B
Data compiled from Penn State Coal Database
and Argonne Premium Coal Sample Program
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Description Ranks of Coal
Peat Lignite Subbituminous Bituminous Anthracite
lt55 Carbon 55-61.5 Carbon 61.5-64 Carbon 64-86 Carbon gt86 Carbon
4500 BTU/lb 7000 BTU/lb 9,300 BTU/lb 11,250 to 14,350 BTU/lb 13,600 BTU/lb
A brownish-black organic matter that looks very much like decayed wood. It is commonly used for peat moss or garden mulch. Peat is not coal. A brownish-black coal with generally high moisture and ash content and the lowest carbon content and energy value. A dull black coal. It has a littler higher energy value than lignite when it burns. A soft, intermediate grade of coal with carbon content and moisture between that of lignite and anthracite. It is the most common and widely used coal in the United States. The hardest type of coal, consisting of nearly pure carbon. It has the highest heating value and the lowest moisture and ash content.
Pre-Cursor to Coal No Rank Lowest Rank Low-Middle Rank High-Middle Rank Highest Rank
Adapted from American Coal Foundation (2010) and
Coal in Pennsylvania (2002)
What are the distinguishing characteristics or
properties of coal? Which rank(s) of coal
would be best for energy production? Which
rank(s) of coal has the most stored energy?
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What tests could we perform to identify the
different ranks of coal in hand sample?
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More than a black rock!
Coal Through a Microscope (2010)http//geology.co
m/articles/coal-through-a-microscope.shtml
1 mm
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Now, you will identify and compare different
types of coal.

• You will examine four unidentified types of coal(
  1 4)
• Document your visual observations about each
  sample
• Document your observations about the burning
  behavior of each sample
• Identify each sample based on your observations
• Consult the Descriptions and Ranks of Coal and
  Peat sheet