Coal
Use of Coal - Past, Present and Future
Formation
Defined as coal is a
chemically and physically heterogeneous, “combustible,” sedimentary rock
consisting of both organic and inorganic material.
Found in seams
coal formed
in situ (that is, where the vegetation grew and fell
Peat bogs- vegetation accumulated
Microbial action break down material
swamps become submerged and were
covered by sedimentary deposits
cycle repeats to form multiple seams
Tectonic and diagenetic processes #
peat → lignite → subbituminous coal → bituminous coal → anthracite
Microbial degradation of cellulose -> conversion of lignin to humic substances -> condensation into coal
decrease in moisture and volatile matter
Classification
proximate
analysis gives the relative amounts of moisture, volatile matter, ash
ultimate analysis
gives the amounts of carbon, hydrogen, nitrogen, sulfur, and oxygen comprising
the coal
Coal Rank
Lignite -> bituminous -> anthracite
Coal Type
Vitrinite, extrinite and inertinite
Microscopic contents called macerals
Vitrinite group macerals are derived from the humification of woody
tissues
Exinite group macerals were derived from plant resins, spores, cuticles,
and algal remains
inertinite group macerals were derived
mostly from woody tissues, plant degradation products, or fungal remains
Different ranks of recoverability
Total, measured, indicated, inferred and recoverable
Most abundant fossil fuel in the world
Variable reserves changing with estimation
2001 estimates at 1083 billion tonnes- around 203 years worth
US(25%), RUSSIA AND CHINA MOST RESERVES
Russia has extensive resources but inaccessible locations
The Dontesk basin used for steaming and coking
Kansk-Achinsk basin used in power stations
Coal consumption fell to 730 million short tons in 2016, the third consecutive year of declining coal consumption
Coal usage in the USA is falling
China however still high as has been increasing up until 2013 with 2015 at 3,732 MT
. Over a third of all housing units were heated by coal in 1950
but only 0.2% were coal heated in 1999.
Coal decreased as oil and gas increased
only 20 million tonnes exported