Download The impact of climate change is one of the biggest and most complicated challenges facing society today

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The impact of climate change is one of the biggest and
most complicated challenges facing society today
Emissions of GHG will increase the average global
temperature by 1.1 to 6.4oC by the end of the 21st century
[1], according to the Intergovernmental Panel on Climate
Change (IPCC).
A global warming of more than 2oC increase in global
average temperature will lead to serious consequences.
The question is: how to reduce greenhouse
gas emissions?
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WHY IS CCS
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CO2 is the most important GHG, and anthropogenic CO2
emissions are mainly a consequence of fossil fuels
being the most important global energy sources.
Enhanced energy efficiency and increased renewable
energy production will reduce CO2 emissions, but
according to the International Energy Agency (IEA),
energy efficiency and renewable energy do not have the
potential to reduce global CO2 emissions as much as
IPCC’s target, i.e. 50 to 80 percent by 2050 [3].
And CO2 Capture and Storage has considered as a
potential to reduce global CO2 emissions
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CARBON CAPTURE
& STORAGE
Presented by: Dao Nha Tam
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OUTLINE
 Introduction
 Capture
technologies
 Transport
 Storage
 Conclusion
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WHAT IS CCS
 Carbon
capture and storage (CCS) is the term that
applies to an array of technologies through which carbon
dioxide (CO2) is captured at industrial point sources such
as fossil-fuel combustion, natural gas refinining…
 Once captured, the CO2 gas is compressed into a
supercritical phase and transported to a suitable
location for injection into a very deep geologic formation.
 Once injected, the CO2 is isolated from the drinking water
supplies and prevented from release into the
atmosphere.
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CARBON CAPTURE
CO2 capture refers to the separation of CO2
from the other components in the flue gas or
process stream of a power plant or an
industrial facility.
 CO2 capture technologies have been applied at
small scales to point sources of CO2, with the
CO2 being used for various purposes.
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CAPTURE TECHNOLOGY
Three main approaches are used to capture CO2
from power plants:
 Post-combustion capture  Flue gas
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Pre-combustion capture  Syngas
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Subcritical pulverized coal, SCPC
Ultra-supercritical pulverized coal, USCPC
Circulating fluidized bed, CFB
integrated gasification combined cycle ,IGCC
Oxy-fuel combustion
 In an oxygen-rich environment
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POST-COMBUSTION
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PRE-COMBUSTION
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OXY-FUEL COMBUSTION
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METHODS FOR SEPARATING CO2
Solvent absorption process
 Adsorption process
 Membranes
 Solid sorbents
 Cryogenic separation by distillation or freezing
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SOLVENT ABSORPTION PROCESS
Solvent absorption is currently industry method
for removing carbon dioxide (CO2) from
industrial waste gas and for purifying natural
gas as well as from syngas
 Absorption processes make use of the
reversible nature of the chemical reaction of an
aqueous alkaline solvent, usually an amine,
with an acid or sour gas
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SOLVENT ABSORPTION PROCESS
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ADSORPTION PROCESS
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Adsorption processes have been employed for CO2
removal from synthesis gas for hydrogen production. It
has not yet reached a commercial stage for CO2
recovery from flue gases
In the adsorption process for flue gas CO2 recovery,
molecular sieves or activated carbons are used in
adsorbing CO2. Desorbing CO2 is then done by the
pressure swing operation (PSA) or temperature swing
operation (TSA). The TSA technique is less attractive
compared to PSA due to the longer cycle times needed
to heat up the bed of solid particles during sorbent
regeneration.
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ADSORPTION PROCESS
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PSA processes rely on pressure,
gases tend to be attracted to solid
surfaces, or "adsorbed". The
higher the pressure, the more gas
is adsorbed; when the pressure is
reduced, the gas is released, or
desorbed.
PSA processes can be used to separate gases in a mixture
because different gases tend to be attracted to different solid
surfaces more or less strongly
Adsorbents for PSA systems are usually very porous materials
chosen because of their large surface areas. Typical
adsorbents are activated carbon, silica gel, alumina and zeolite
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MEMBRANES
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Membrane processes are used commercially for CO2
removal from natural gas at high pressure and at high CO2
concentration.
The membrane option currently receiving the most
attention is a hybrid membrane – absorbent (or solvent)
system. These systems are being developed for flue gas
CO2 recovery.
Membranes provide a very high surface area between a
gas stream and a solvent. And the membrane forms a gas
permeable barrier between a liquid and a gaseous phase
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MEMBRANES
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In general, the membrane is not
involved in the separation process.
In the case of porous membranes,
gaseous
components
diffuse
through the pores and are
absorbed by the liquid;
in cases of non-porous membranes they dissolve in the
membrane and diffuse through the membrane.
The selectivity of the partition is primarily determined by the
absorbent (solvent). Absorption in the liquid phase is determined
either by physical partition or by a chemical reaction.
The advantages of this systems are avoidance of foaming,
flooding entrainment and channeling occurring in conventional
solvent absorption systems where gas and liquid flows are in
direct contact.
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SOLID SORBENTS
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The combustion flue gas is put in contact with the sorbent in a
suitable reactor to allow the gas-solid reaction of CO2 with the
sorbent (usually the carbonation of a metal oxide).
The solid can be easily separated from the gas stream and sent for
regeneration in a different reactor. Instead of moving the solids, the
reactor can also be switched between sorption and regeneration
modes of operation in a batch wise, cyclic operation.
Sorbent has to have good CO2 absorption capacity, chemical and
mechanical stability for long periods of operation in repeated cycles.
So, sorbent performance and cost are critical issues in all postcombustion systems, and more elaborate sorbent materials are
usually more expensive than commercial alternatives.
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CRYOGENIC SEPARATION BY DISTILLATION
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Cryogenic separation unit are
operated
at
extremely
low
temperature and high pressure to
separate components according to
their different boiling temperatures.
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Cryogenic separation is widely used commercially for purification of
CO2 from streams that already have high CO2 concentration.
The advantage of this method is producing liquid CO2 or pure CO2 gas
stream in high pressure which would be liquefied more easily.
There are some difficulties for applying this method as well. For dilute
CO2 stream, the refrigeration energy is high. Water has to be removed
before the cryogenic cooling step to avoid blockage from freezing.
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TRANSPORT
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After capture, the CO2 would have to be
transported to suitable storage sites.
Although CO2 is transported via pipelines,
ships, and tanker trucks for enhanced oil
recovery (EOR) and other industrial
operations, pipeline transport is considered
to be the most cost-effective and reliable
method of transporting CO2.
Tanker Transport of CO2
Transporting CO2 via pipelines requires gas
 Supercritical (dense) or liquid state  to reduce its volume.
 Dry, pure stream of CO2  to reduce the risk of pipeline corrosion
Though mixed wet streams of CO2 can be transported they may require
the use of corrosion-resistant steel, which is more expensive than the
materials typically used.
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STORAGE
Various methods have been conceived for the
storage ('sequestration') of carbon dioxide,
including:
 Gaseous storage in various deep porous
geological formations.
 Liquid storage in the deep ocean
 Solid storage by reaction of CO2 with metal
oxides to produce stable.
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GEOLOGICAL STORAGE
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Geological storage involves the injection of CO2 into permeable rock
formations sealed by impermeable, dense rock units (cap rocks) more
than 800 meters below the Earth’s surface.
Geological storage involves a combination of physical and geochemical
trapping mechanisms.
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GEOLOGICAL STORAGE OPTIONS
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OCEAN STORAGE
There are three possibilities for using the ocean
environment to store carbon: in geological
formations under the seabed, on the seafloor, and
in the water column of the deep ocean.
 CO2 in the atmosphere gradually dissolves into
ocean surface water until an equilibrium is
reached.
 However, the storage is not permanent. Once in
the ocean, the CO2 eventually dissolves, disperses
and returns to the atmosphere as part of the
global carbon cycle.
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OCEAN STORAGE
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MINERAL CARBONATION
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Mineral carbonation is based on the reaction of CO2 with metal
oxide bearing materials to form insoluble carbonates, with calcium
and magnesium being the most attractive metals. In nature such a
reaction is called silicate weathering and takes place on a
geological time scale.
Suitable
materials
may be abundant
silicate
rocks,
serpentine
and
olivine minerals or
industrial residues,
such as slag from
steel production or fly
ash.
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MINERAL CARBONATION
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With present technology there is always a net
demand for high grade energy to drive the mineral
carbonation process that is needed for:
(i) the preparation of the solid reactants, including
mining, transport, grinding and activation when
necessary;
(ii) the processing, including the equivalent energy
associated with the use, recycling and possible
losses of additives and catalysts;
(iii) the disposal of carbonates and byproducts
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CONCLUSTION
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Carbon capture and storage technologies could provide a partial
solution to this dilemma by facilitating less costly reductions in
carbon emissions through the continued use of fossil fuels.
Despite significant experience with storage of CO2 and other
substances in underground reservoirs, there is substantial
uncertainty regarding how much CO2 such reservoirs can hold, how
long injected CO2 would remain trapped, and whether injected CO2
would escape from storage reservoirs to other formations.
The effects of ocean storage are even more uncertain, raise
additional environmental concerns, and are more likely to generate
controversy.
Storage of CO2 as carbonates could lessen many of the concerns
related to ocean storage but would generate other environmental
concerns and would entail substantially higher storage costs.
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REFERENCES
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[1] Intergovernmental Panel on Climate Change (IPCC), Climate Change 2007: The Physical
Science Basis, Summary for Policymakers, February 2007, http://www.ipcc.ch/SPM2feb07.pdf.
[2] Intergovernmental Panel on Climate Change (IPCC), Climate Change 2001: Synthesis report.
Cambridge University Press, Cambridge, UK, 2001, http://www.grida.no/climate/ipcc_tar/.
[3] International Energy Agency (IEA), World Energy Outlook 2006, OECD and International
Energy Agency report, Paris, France, 2006.
[4] The EU Technology Platform for Zero Emission Fossil Fuel Power Plants (ZEP), A vision for
Zero Emission Fossil Fuel Power Plants. Directorate-Generale for Research, Brussel, Belgium,
May 2006,
http://www.zero-emissionplatform.eu/website/docs/ETP%20ZEP/ZEP%20Vision.pdf.
[5] A. Stangeland, A Model for the CO2 Capture Potential, Bellona Paper, Oslo, Norway, 2006,
http://www.bellona.no/filearchive/fil_Paper_Stangeland_-_CCS_potential.pdf.
[6] http://www.bellona.org/position_papers/WhyCCS_1.07
[7] World Resources Institute (WRI). CCS Guidelines: Guidelines for Carbon Dioxide Capture,
Transport, and Storage. Washington, DC: WRI, 2008
[8] Greenpeace International: Why carbon capture and storage won’t save the climate, 2008
[9] Intergovernmental Panel on Climate Change: IPCC Special Report on Carbon Dioxide
Capture and Storage, 2005
[10] http://www.vattenfall.com/en/ccs/technology.htm
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REFERENCES
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[11] http://www.co2crc.com.au/publications/all_factsheets.html
[12] Archer, D.E., H. Kheshgi, and E. Maier-Reimer: Multiple timescales for neutralization
of fossil fuel CO2. Geophysical Research Letters, 24(4), 405-408. 1997
[13] Archer, D.E., H. Kheshgi, and E. Maier-Reimer: Dynamics of fossil fuel neutralization
by Marine CaCO3. Global Biogeochemical Cycles, 12(2), 259-276. 1998
[14] Chargin, Anthony, and Robert Socolow. Fuels Decarbonization and Carbon
Sequestration: Report of a Workshop. Princeton, NJ: Princeton University, Center for
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[15] U.S. Department of Energy. 2003. Carbon Sequestration [Web Page]. National
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[16] Adams, D., W. Ormerod, P. Riemer, and A. Smith. 1994. Carbon Dioxide Disposal
from Power Stations. Cheltenham, United Kingdom: International Energy Agency
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[17] Herzog, Howard J., Elisabeth Drake, and Eric Adams. 1997. CO2 Capture, Reuse, and
Storage Technologies for Mitigating Global Climate Change. Cambridge, MA:
Massachusetts Institute of Technology Energy Laboratory, A White Paper.
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