2. OUTLINE
A. INTRODUCTION
Carbon dioxide emission source
About Carbon dioxide capture (CCS)
Methods of CO2 capture
Challenges towards CO2 capture
B. CO2 STORAGE
C. CO2 SEQUESTRATION
D. INDUSTRIAL APPROACH
4. FOSSIL FUEL??
Fossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead
organisms.
Levels (proved reserves) during 2005–2007
Coal: 997,748 million short tonnes (905 billion metric tonnes), 4,416 billion barrels (702.1 km3) of
oil equivalent
Oil: 1,119 billion barrels (177.9 km3) to 1,317 billion barrels (209.4 km3)
Natural gas: 6,183–6,381 trillion cubic feet (175–181 trillion cubic metres), 1,161 billion barrels
(184.6×109 m3) of oil equivalent
Flows (daily production) during 2006
Coal: 18,476,127 short tonnes (16,761,260 metric tonnes), 52,000,000 barrels (8,300,000 m3) of
oil equivalent per day
Oil: 84,000,000 barrels per day (13,400,000 m3/d)
Natural gas: 104,435 billion cubic feet (2,960 billion cubic metres), 19,000,000 barrels (3,000,000
m3) of oil equivalent per day
Years of production left in the ground with the current proved reserves and flows above
Coal: 148 years
Oil: 43 years
Natural gas: 61 years
5. Carbon dioxide emission: Worldwide scenario
Carbon dioxide emissions from various fuel and technology options
6. Carbon Dioxide Emission source
A. Power plants: Combustion of fossil fuel e.g. coal and
hydrocarbons with air or oxygen, or with a combination of
oxygen and steam, such as SR (steam reforming), POX (partial
oxidation) of hydrocarbons Fermentation of grain for the
production of beer, or ethanol for spirits
B. Off-gases from petroleum refineries, oxidation of ethylene,
and automotive combustion
C. Cement and Steel production
D. Urea production and Hydrogen generation
E. Natural gas wells
F. Vehicular emission
7. Available methods for CO2 capture
Absorption
Primary amines, including monoethanol amine (MEA) and diglycolamine (DGA).
Secondary amines, including diethanol amine (DEA) and diisopropyl amine
(DIPA).
Tertiary amines, including triethanol amine (TEA) and methyldiethanol amine
(MDEA).
Cryogenic are chiefly aimed for IGCC configurations and for combustion in
oxygen/recycled CO2. In this process, CO2is separated from the other gases by
condensing it out at cryogenic temperatures.
Membrane based gas separation uses the difference in the interaction between
the membrane material and various components gases of flue gas. This selective
affinity for one gas causes it to permeate faster thus achieving its separation.
Some examples of viable membranes materials are polymer membranes,
palladium membranes, facilitated transport membranes and molecular sieves.
The use of polyphenyleneoxide and polydimethyl siloxane membranes for gas
separation; polypropylene membranes for gas absorption and ceramic based
membrane systems have their own advantages and limitations.
8. Gas-solid adsorption adsorb CO2on a bed of adsorbent materials such as zeolite, alumina or
activated carbon. Various techniques employed for CO2separation include-Pressure Swing
Adsorption (PSA), Vacuum Pressure Swing Adsorption (VPSA), Thermal (or temperature) Swing
Adsorption (TSA), Electric swing and washing processes. In PSA, CO2adsorbed on the surface is
released by lowering the bed pressure. In VPSA, vacuum is applied to further pull the CO2out of the
bed. The regeneration cycles are short (usually requiring a few seconds). In TSA, the saturated bed
is heated to release the adsorbed CO2. Electric swing and washing are the commonly used
regeneration methods applied after the evolution of IGCC (Integrated Gasification Combined Cycle)
supported power plants.
10. Practical issues towards efficient CCS Process
Flue gas composition
Regeneration energy Why CCS not getting
Flue gas temperature commercialized?
Oxygen
Sox
a) Cost of capture > Cost of Fuel
Nox
b) Environmental effectiveness
Fly ash
Soot c) Ease of application- CCS plant
Waste products performance/ Life/ maintenance
Corrosion d) Political acceptability
Cost
11. Challenges towards CO2 capture
A. Material/Adsorbent
High CO2 adsorption capacity-High surface area, favorable pore
characteristics
selectivity towards CO2 to capture in presence of component
gases-Functionalization
Economical- Low cost synthesis, inexpensive template
Operative under flue gas conditions- Thermal and Hydrothermal
stability
Regenerative and capable of being operated for multicycle-
Efficiency with good Mechanical stability
12. Adsorbents/ Materials being explored so far.....
Zeolites: 13X, DDZ-70, 4A etc.
Aluminophosphates (AlPO, SAPO)
Silica gel
Activated Carbon
Mesoporous adsorbents (MCM-41, SBA-15, KIT-5 etc.)
Enzymatic approach
Alumina
Low cost adsorbents derived from flyash, rice husk and other cheap natural
sources
Hydrotalcites, metal loaded adsorbents etc.
13. Challenges towards CO2 capture
B. Industrial acceptance
1. Cost of capture being more
than the cost of fuel
2. Flexible environmental
policies
3. Efficiency loss due to CO2
capture (10-25%)
4. Government policy issues
5. Unavailability of efficient
techno-economical solutions
towards CCS
14. CO2 STORAGE
The main mechanisms that trap CO2 in the subsurface are the following:
—trapping as a result of the buoyancy of CO2 compared with water or brine,
in structural or stratigraphic traps beneath cap rocks,
—trapping as a residual saturation along the CO2 migration path within the
reservoir rock,
—dissolution into the native pore fluid (most commonly brine),
—reaction of acidified groundwaters with mineral components of the
reservoir rock, and
—adsorption onto surfaces within the reservoir rock, e.g. onto the
carbonaceous macerals that are the principal components of coal.
15. CO2 storage: Issues
1. Sedimentary basins do not occur in every country in the world. Nor are all
sedimentary basins suitable for CO2 storage.
2. Typical physical conditions for geological CO2 storage: One tonne of CO2 at a
density of 700 kg m−3 occupies 1.43 m3, but at 0°C and 1 atmosphere, 1 tonne of CO2
occupies approximately 509 m3.
3. Storage mechanisms:
The main mechanisms that trap CO2 in the subsurface are the following:
I) trapping as a result of the buoyancy of CO2 compared with water or brine, in
structural or stratigraphic traps beneath cap rocks, ii) trapping as a residual saturation
along the CO2 migration path within the reservoir rock, iii) dissolution into the native
pore fluid (most commonly brine), iv) reaction of acidified groundwaters with mineral
components of the reservoir rock, and v) adsorption onto surfaces within the reservoir
rock, e.g. onto the carbonaceous materals that are the principal components of coal.
4. Storage capacity
5. CO2 leakage
16. CO2 SEQUESTRATION
Sequestration
To set off or apart; separate; segregate
Why sequester CO2?
Removal from atmosphere reduces the impact that anthropogenic CO2
emissions has on global warming.
Natural Carbon Dioxide Sinks
Forests (terrestrial sequestration via photosynthesis)
There are three major steps involved in carbon sequestration:
1. Separate and capture CO2 from the flue gases and exhaust of power
plants, refineries, oil sands operation and heavy oil upgrading facilities,
cement plants, steel plants, ammonia plants and other chemical plants.
(EOR)
2. Concentrate it for transportation to and storage in distant reservoir
locations. (In deep Ocean)
3. Convert it into stable products by biological or chemical means or
allow it to be absorbed by natural sinks such as terrestrial or ocean
ecosystem. (Chemical feedstock)
19. Industrial overview and Future scope
Non-carbon based energy
Combustion based
-Hydrogen as a fuel
2 H2 (g) + O2 (g) 2 H2O (g)
-Photoelectric
-Nuclear Power
Costs:Time for research & development
Renewable Energy
Solar
Geothermal
Hydroelectric
Wind
Ocean tides
Cost:Altered ecology & biodiversity
Consider: Fossil fuels incur same costs
20. Worldwide CO2 capture status
Kansai Electric Power Company and Mitsubishi Heavy Industries have been eveloping
sterically hindered amines, the most well known are called KS-1 and KS-2. These amines
have the advantage of a lower circulation rate due to a higher CO2 loading differential, a
lower regeneration temperature and a lower heat of reaction. They are also non-corrosive
to carbon steel at 130°C in the presence of oxygen. A first commercial plant using KS-1
for Petronas Fertiliser Kedah Sbn Bhd’s fertilizer plant in Malaysia has been in operation
since 1999 (Mimura et al., 2001).
The membrane technology was developed by Aker Kvaerner and used in gas separation
applicationswithin the oil and gas industry (Herzog and Falk-Pedersen, 2001). Scale-up
to sizes required to capture CO2 from large power plants is considered to be a difficult
issue.
22. R&D needs
R&D related to absorbents
· Reduce steam consumption and temperature requirement for
regeneration
o More energy efficient amines required (lower energy
requirement for regeneration, lower regeneration temperature,
higher concentration)
o Optimise blend of amines
· Reduce power consumption
o Develop amines with a higher CO2 loading that could be
applied at a higher concentration to reduce pump requirements
and equipment size
o Optimise blend of amines
· Decrease loss of amine into the flue gas or CO2
o Amines with a lower vapour pressure are desirable
· Reduce degradation of amines
o Develop amines less sensitive to high temperature, SOx, Nox, O2
o Develop inhibitors, process modifications, membranes
· Develop other types of absorbents
23. Other R&D needs
Other areas for development
· Integration possibilities with power plant should be investigated
o Integration between reboiler and reclaimer and IP steamextraction
o Use of heat from CO2 compression intercooling for feedwater preheating
o Find integration possibilities for use of heat from flue gas cooler, lean amine
solution cooler, reflux condenser and CO2 dryer (e.g. district heating, feed
water preheating etc.)
· Reduced flue gas blower requirement
o More efficient packing to reduce absorber pressure drop
· Process optimisation for large scale plant
o Process modifications, e.g. split flow solvent process (lean and semi-lean
solution)
o Improve simulation tools used for optimisation to better predict performance
o Investigate possibilities for cost reductions due to economy of scale
· Demonstration of long-term operational availability and reliability on a
full-scale power plant using relevant fuels.
24. COMMERCIAL SCOPE OF CCS
The efficiency losses due to CO2 capture are relatively modest when one considers
the environmental gains, i.e., nearly 100% CO2 capture, no SOx, NOx and particulate
matter emissions.
In fact, both plants (NG and SG) require no smokestack. Furthermore, both plants
produce salable byproducts: argon and nitrogen.
The captured CO2 may also derive an economic revenue if it is used for enhanced
oil recovery or as a chemical feedstock, or if the plant is avoiding a carbon tax.
Where CCS can be utilized?
1. Carbon credit
2. Conversion of CO2 to useful and valuable products such as syn gas, methanol etc.
3.Supply of pure CO2 to beverage industry
4. CO2 heat pumps
25. Instruments to control carbon emissions
A. Cap and Trade scheme
B. Carbon Tax
C. Hybrid: Long term emission certificates coupled with
central bank of carbon
D. Baseline and Credit
E. Feebate
F. Emission performance standard
G. CO2 purchase contract
26. SUMMARY
1. Post-combustion carbon dioxide capture technologies can already be used under
certain conditions and pre-combustion separation uses technologies that are well
established in other industrial sectors, such as fertiliser generation and hydrogen
production. However, alternative technologies are being explored to further drive down
costs and improve overall energy efficiency. New research has demonstrated how some
new methods could reduce the cost of carbon capture by 20-30 per cent whilst also
producing hydrogen, which could be used to fuel cars.
2. Important considerations for choice of absorbent include CO 2-loading (mol CO2/mol
amine), high solvent concentration in the aqueous solution, heat of reaction, heat of
vaporization, reaction rate, the temperature level required for regeneration, corrosion
issues and also cost.
3. Adsorption > Absorption > Membrane separation > Cryogenic separation
27. Conclusions
STAGE 1:Need to develop efficient adsorbents/search for a functional
molecule
1a: Evaluation of adsorption performance of adsorbents/ functional
molecules
1b: Characterization of adsorbents
1c: Measurement of adsorption kinetics and equilibrium curves
1d: Evaluation of adsorbent thermodynamics and dynamic (cyclic)
performance
(Observations in terms of: 1. Adsorption capacity, 2. Cyclic performance, 3.
Heat transfer coefficient (W/m2K) optimization, 4. Specific cooling power
(W/kg)and efficiency)
STAGE 2: Selection of efficient coating method: 1. Dip coating, 2. Spray
coating, 3. Wet impregnation, 4. Sol-gel synthesis, 5. In-situ functionalization,
6. Hydrothermal synthesis, 7. Microwave synthesis, Direct or in-situ synthesis
over honeycomb substrate ( fined tubes, foams, fibres, etc), 8. Other possible
route
STAGE 3: Commercialization