Developed by: TESSE Graduate Student Fellows Penn State University Introduction to Coal

What is coal?  The 3 P’s of coal formation:  Plants  Preservation  Pressure (& temperature)

 Large amounts of plant material accumulate over thousands of years, usually in a swamp. (Peat) 1. PLANTS

Smithsonian National Natural History Museum’s recreation of coal swamp 300 million years ago Modern-day swamp of the Mississippi River Delta

 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 PRESERVATION 2. PRESERVATION

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

 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 earth’s 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 3. PRESSURE & temperature 3. PRESSURE & temperature Coalification: How peat becomes coal

Coal Classification  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 Kentucky Geological Survey (2006)

Coal’s Components  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) Coal in Pennsylvania ( 2002)

Distinguishing among ranks of coal How do %C and heating value change with rank? Anthracite Bituminous Data compiled from: Penn State Coal Database and Argonne Premium Coal Sample Program

A A B B How does oxygen and hydrogen content vary with rank? Data compiled from: Penn State Coal Database and Argonne Premium Coal Sample Program

Description & Ranks of Coal PeatLigniteSubbituminousBituminousAnthracite <55% Carbon % Carbon % Carbon64-86% Carbon>86% Carbon 4500 BTU/lb7000 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 RankLow-Middle RankHigh-Middle RankHighest Rank 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? Adapted from American Coal Foundation (2010) and Coal in Pennsylvania (2002)

What tests could we perform to identify the different ranks of coal in hand sample?

More than a black rock! Coal Through a Microscope (2010) through-a-microscope.shtml 1 mm

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