2. WHAT IS CARBON CAPTURE AND
STORAGE?
• CCS is a technology that will attempt to
prevent large quantities of CO2 from
being released into the atmosphere from
the use of fossil fuels in power generation
and other industries.
• It is often regarded as a means of
mitigating the contribution of fossil fuel
emissions to global warming.
5. CAPTURING CARBON
• There are essentially three ways to
capture the carbon dioxide from a
power plant:
• Before the fuel is burned
(precombustion),
• After the fuel is burned (postcombustion),
or
• By burning the fuel in more oxygen
and storing all the gases produced as
a result (oxyfuel).
6. PRECOMBUSTION
In precombustion, the aim is
to remove the carbon from
coal
fuel before it's burned. The
coal is
reacted with oxygen to
make syngas (synthesis gas),
a mixture of carbon monoxide
and hydrogen gases. The
hydrogen can be removed
and either burned directly as
fuel or compressed and
stored for use
in fuel-cell cars. Water is
added to the carbon monoxide
to make carbon dioxide (which
is stored) and additional
hydrogen, which is added to
the hydrogen previously
7. POSTCOMBUSTION
• In postcombustion, we're
trying to remove carbon
dioxide from a power
station's output after a
fuel has been burned.
That means waste gases
have to be captured and
scrubbed clean of their
CO2 before they travel up
smokestacks. The
scrubbing is done by
passing the gases
through ammonia, which
is then blasted clean with
steam, releasing the CO2
for storage.
8.
9. OXYFUEL
• Power plants don't produce pure CO2:
because there's often not enough oxygen
for complete combustion they produce
other pollutant gases as well.
• One way to purify the exhaust is to blow
extra oxygen into the furnace so the fuel
burns completely producing relatively pure
steam and CO2.
• Once the steam is removed (by cooling
and condensing it to make water), the
CO2 can be stored.
11. • Storing carbon dioxide under Earth's
surface is called geo-sequestration and
uses things like worked out oil fields,
aquifers, or other rock formations deep
underground.
• Oil companies already pump CO2 into
underground rocks to flush oil to the
surface.
• Storing CO2 in the oceans.
• Storing CO2 by reacting it with
minerals, though that requires a lot
more energy.
12. MAJOR STORAGE SITES IN THE
WORLD
• Sleipner,
Norwegian North
Sea
• Altmark, Germany
• Weyburn, Canada
• In Salah, Algeria
• Miranga, Brazil
• Hontomin, Spain
• Hastings, Texas,
USA
13. ADVANTAGES
• CCS applied to a modern conventional
power plant could reduce CO2 emissions
to the atmosphere by 80-90 % compared
to a plant without CCS.
• The solvents used to capture CO2 from
the flue gases will remove some
nitrogen oxides and sulphur oxides.
14. DISADVANTA
GES
• Increase significantly the emissions of
acid gas pollutants.
• Capturing and compressing C02 requires
much energy and would increase the fuel
needs of a coal-fired plant with CCS by 25-
40%.
• These and other system costs are
estimated to increase the cost of energy
from a new power plant with CCS by 21-90
%.
15. CARBON CAPTURE:
ENVIRONMENTAL
IMPACTS
• In ocean storage carbon dioxide reacts
with water to form acid, so the oceans
could become significantly more acidic .
• Another difficulty is that the CO2 would
also eventually return to the
atmosphere.
• In addition to the global climate change
impact of CO2 returning to the
atmosphere, leakages pose local risks
to health and ecosystems.
