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.

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The question is: how to reduce greenhouse

gas emissions?

WHY IS CCS

CO2 is the most important GHG, and anthropogenic CO2

emissions are mainly a consequence of fossil fuelsbeing the most important global energy sources.

Enhanced energy efficiency and increased renewableenergy production will reduce CO2 emissions, butaccording to the International Energy Agency (IEA),energy efficiency and renewable energy do not have thepotential to reduce global CO2 emissions as much asIPCC’s target, i.e. 50 to 80 percent by 2050 [3].

And CO2 Capture and Storage has considered as apotential 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 thatapplies to an array of technologies through which carbondioxide (CO2) is captured at industrial point sources suchas fossil-fuel combustion, natural gas refinining…

Once captured, the CO2 gas is compressed into asupercritical phase and transported to a suitablelocation for injection into a very deep geologic formation.

Once injected, the CO2 is isolated from the drinking watersupplies and prevented from release into theatmosphere.

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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

Subcritical pulverized coal, SCPC

Ultra-supercritical pulverized coal, USCPC

Circulating fluidized bed, CFB

Pre-combustion capture Syngas

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

Adsorption processes have been employed for CO2removal from synthesis gas for hydrogen production. Ithas not yet reached a commercial stage for CO2recovery from flue gases

In the adsorption process for flue gas CO2 recovery,molecular sieves or activated carbons are used inadsorbing CO2. Desorbing CO2 is then done by thepressure swing operation (PSA) or temperature swingoperation (TSA). The TSA technique is less attractivecompared to PSA due to the longer cycle times neededto heat up the bed of solid particles during sorbentregeneration.

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ADSORPTION PROCESS

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.

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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

MEMBRANES

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 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;

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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.

in cases of non-porous membranes they dissolve in the

membrane and diffuse through the membrane.

SOLID SORBENTS

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 post-

combustion systems, and more elaborate sorbent materials are

usually more expensive than commercial alternatives.

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CRYOGENIC SEPARATION BY DISTILLATION

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.

TRANSPORT

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.

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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.

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

Geological storage involves the injection of CO2 into permeable rockformations sealed by impermeable, dense rock units (cap rocks) morethan 800 meters below the Earth’s surface.

Geological storage involves a combination of physical and geochemicaltrapping mechanisms.

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GEOLOGICAL STORAGE OPTIONS

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OCEAN STORAGE

There are three possibilities for using the oceanenvironment to store carbon: in geologicalformations under the seabed, on the seafloor, andin the water column of the deep ocean.

CO2 in the atmosphere gradually dissolves intoocean surface water until an equilibrium isreached.

However, the storage is not permanent. Once inthe ocean, the CO2 eventually dissolves, dispersesand returns to the atmosphere as part of theglobal carbon cycle.

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OCEAN STORAGE

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MINERAL CARBONATION Mineral carbonation is based on the reaction of CO2 with metal

oxide bearing materials to form insoluble carbonates, with calciumand magnesium being the most attractive metals. In nature such areaction is called silicate weathering and takes place on ageological time scale.

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Suitable materials

may be abundant

silicate rocks,

serpentine and

olivine minerals or

industrial residues,

such as slag from

steel production or fly

ash.

MINERAL CARBONATION

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 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 [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 [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

Energy and Environmental Studies, School of Engineering and Applied Science. 1997

[15] U.S. Department of Energy. 2003. Carbon Sequestration [Web Page]. National

Energy Technology Laboratory 2003 [cited January 2003]. Available from

http://www.netl.doe.gov/coalpower/sequestration/

[16] Adams, D., W. Ormerod, P. Riemer, and A. Smith. 1994. Carbon Dioxide Disposal

from Power Stations. Cheltenham, United Kingdom: International Energy Agency

Greenhouse Gas

R&D Program.

[17] Herzog, Howard J., Elisabeth Drake, and Eric Adams. 1997. CO2 Capture, Reuse, and

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Massachusetts Institute of Technology Energy Laboratory, A White Paper.

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