Bolaleman
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 Posted: Tue Oct 07, 2008 1:54 pm Post subject: Clean Coal Power - An Illusion? |
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In the USA about half of the electricity is produced from burning
coal. Actually, more than 40 percent of its carbon dioxide (CO2)
emissions are escaping into the atmosphere and contributing to the
greenhouse effect.
Now there is a new technology available, called the "oxyfuel process".
The trick: coal is not burned any more in normal air but in a blend of
pure oxygen and CO2. By stripping out the nitrogen and other gases
from the air, the burning coal produces mostly water vapor and nearly
pure carbon dioxide. After condensing the water, the CO2 can be
bottled and pumped underground (in this case, into an old natural gas
field to get even more methane out of the ground). One of the problems
is that stripping nitrogen out of air requires a good chunk of the
energy produced by the burning of the coal in the first place. After
all, nitrogen makes up 78 percent of the air we breathe.
This doesn´t sounds too bad but the question here is how safe and
permanent a geologic storage of the CO2 is. What happens if there is a
leak? Is it possible to store CO2 for thousands of years without any
environmental problems (this gas can interfere with groundwater and
contaminate it with heavy metals, for instance). How real is the
possibility that the CO2 reacts with the rocks to create permanent
storage as carbonate minerals?
For me there are still a lot of open questions and it is probably too
early to talk about "Clean Coal Power".
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