CARBON DIOXIDE CAPTURE, STORAGE AND SEQUESTRATION

VIVEK KUMAR

OUTLINE

A. INTRODUCTION Carbon dioxide emission source About Carbon dioxide capture (CCS) Methods of CO

2 capture

Challenges towards CO2 capture

B. CO2 STORAGE

C. CO2 SEQUESTRATION

D. INDUSTRIAL APPROACH

Physical properties of Carbon dioxide

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

Carbon dioxide emissions from various fuel and technology options

Carbon dioxide emission: Worldwide scenario

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

Available methods for CO2 capture

AbsorptionPrimary 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.

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.

Summary sheet for methods of CO2 separation

techniques

Practical issues towards efficient CCS Process

Flue gas composition

Regeneration energy

Flue gas temperature

Oxygen

Sox

Nox

Fly ash

Soot

Waste products

Corrosion

Cost

Why CCS not getting commercialized?

a) Cost of capture > Cost of Fuel

b) Environmental effectiveness

c) Ease of application- CCS plant

performance/ Life/ maintenance

d) Political acceptability

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

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.

B. Industrial acceptance

Challenges towards CO2 capture

1. Cost of capture being more than the cost of fuel2. Flexible environmental policies3. Efficiency loss due to CO2 capture (10-25%)4. Government policy issues5. Unavailability of efficient techno-economical solutions towards CCS

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 thereservoir 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.

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

3.The absence of policy,legislation and a proper regulatory framework is currentlya barrier to the deployment of CO2 geological storage.

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 SinksForests (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)

Geological Sequestration

Problems

Costly to capture and separate CO2 ($65/ton)

Difficult to predict CO2 movement underground

Loss of CO2 to atmosphere???

Industrial overview and Future scope

Non-carbon based energyCombustion based-Hydrogen as a fuel

2 H2 (g) + O2 (g) 2 H2O (g)-Photoelectric-Nuclear Power

Costs:Time for research & development

Renewable EnergySolar

GeothermalHydroelectric

WindOcean tides

Cost:Altered ecology & biodiversityConsider: Fossil fuels incur same costs

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.

Worldwide CO2 capture status

Commercial CO2 plants

(main source: IEA GHG data base, see www.co2sequestration.info)

R&D needs

R&D related to absorbents· Reduce steam consumption and temperature requirement forregenerationo More energy efficient amines required (lower energyrequirement for regeneration, lower regeneration temperature,higher concentration)o Optimise blend of amines· Reduce power consumptiono Develop amines with a higher CO

2 loading that could be

applied at a higher concentration to reduce pump requirementsand equipment sizeo Optimise blend of amines· Decrease loss of amine into the flue gas or CO

2

o Amines with a lower vapour pressure are desirable· Reduce degradation of amineso Develop amines less sensitive to high temperature, SOx, Nox, O

2

o Develop inhibitors, process modifications, membranes· Develop other types of absorbents

Other R&D needs

Other areas for development· Integration possibilities with power plant should be investigatedo Integration between reboiler and reclaimer and IP steamextractiono Use of heat from CO2 compression intercooling for feedwater preheatingo 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 requiremento More efficient packing to reduce absorber pressure drop

· Process optimisation for large scale planto Process modifications, e.g. split flow solvent process (lean and semi-lean solution)o Improve simulation tools used for optimisation to better predict performanceo Investigate possibilities for cost reductions due to economy of scale

· Demonstration of long-term operational availability and reliability on afull-scale power plant using relevant fuels.

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 credit2. Conversion of CO

2 to useful and valuable products such as syn gas, methanol etc.

3.Supply of pure CO2 to beverage industry

4. CO2 heat pumps

COMMERCIAL SCOPE OF CCS

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

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 CO2-loading (mol CO

2/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

SUMMARY

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

Thank You