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Environmental Hazards of Coal
Burning Power Plants
Delfin M. Herrera Jr.
BSEE 5-1
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Although coal provides electricity
for our homes, the burning of coal
in power plants is a major causeof environmental pollution and
global warming.
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Global Warming due to Coal Combustion
Carbon dioxide emissions are the
essential outcome of coal combustion in
power plants.
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Acid Deposition Due to Coal Burning
Combustion of coal in power plants
converts them to sulfur and nitrogen
oxides respectively. These oxides, uponreaction with water in the atmosphere,
result in precipitation of acid, sometimes
also called acid rain.
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Particulate Matter and Ground-
Level Ozone The coal-fired power plants release solid
and liquid particles that
remain suspended in the air and appear inthe form of smog
(combination of smoke and fog)
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Mercury Emissions from Coal Burning
Most coal-fired power plants are major
mercury emitters;
mercury is present in coal in small tracesand is released to the
atmosphere during combustion.
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How can we reduce pollution from
coal-fired power plants? 'Clean coal technology' describes a new
generation of energy processes, some
currently available and others beingdeveloped, which have the ability to
sharply reduce air emissions and other
pollutants.
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Among the key options under development
for use alone or in combination are:
- Optimising existing plants so they reduceemissions and increase the amount of electricityproduced with the same amount of coal.
- Continuing to develop and refine best-availablecombustion technology, including circulatingfluidised-bed (CFB) technology, which includessupercritical and ultra supercritical combustion.
This option may also include burning biomass asa fuel, thus reducing the level ofCO2 emissions,and oxy-combustion for collecting CO2-rich fluegas.
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CFB
ACirculating Fluidized Bed is a relatively new and evolvingtechnology that has become a very efficient method of generatinglow-cost electricity while generating electricity with very lowemissions and environmental impacts.
In a Circulating Fluidized Bed combustion process, crushed coal ismixed with limestone and fired in a process resembling a boilingfluid. The limestone removes the sulfur and converts it into anenvironmentally-benign powder that is removed with the ash.
Fluidized bed boilers are capable of burning a wide range of fuelscleanly, including biomass fuels such as wood waste.
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- Gasification - turning coal into a gas and
removing impurities from the coal gas
before it is combusted.
- Carbon capture and storage (CCS) -
capturing the carbon dioxide from the flue
gas and storing it underground or reusing
it
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Etc.
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