17-binu cb-carbondioxide capturing and storage

7/30/2019 17-Binu CB-Carbondioxide Capturing and Storage

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CARBONDIOXIDE CAPTURING AND STORAGE

SEMINAR REPORT

Submitted By:

BINU CB

MECHANICAL ENGINEERING

SREE NARAYANA GURUKULAM COLLEGE OF ENGINEERING

KADAYIRIPPU

MAHATMA GANDHI UNIVERSITY

KOTTAYAM 686 560

2009


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SNG COLLEGE OF ENGINEERING, KADAYIRIPPU

DEPARTMENT OF MECHANICAL ENGINEERING

CERTIFICATE

Certified that the seminar report CARBONDIOXIDE CAPTURING

AND STORAGE is the bonafide work done by BINU CB in partial

fulfillment of award of B.Tech degree in Mechanical Engineering.

Guide:

PP BINU Dr. T P LUKOSE

Lecturer Head of the Department


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ACKNOWLEDGEMENT

First of all I would like to thank God Almighty for all the blessings bestowed

upon me without which the work would not have been a reality.

I express my sincere gratitude to my guide Mr. PP Binu Lecturer, Department of

Mechanical Engineering, Sree Narayana Gurukulam College of Engineering, for his

advice and encouragement which were indispensable for the fulfillment of this

presentation.

I am also thankful to Dr. T.P. Lukose, Head of the Department, Mechanical

Engineering, Sree Narayana Gurukulam College of Engineering for his whole hearted

support.

I express my sincere gratitude to our group tutor Mrs. Jayasree K.S,

Asst.Professor, Department of Mechanical Engineering, Sree Narayana Gurukulam

College of Engineering and also to our staff advisor for his kind co-operation and

guidance for preparing and presenting this seminar.

I am also thankful to all the other faculty members of Mechanical department and

my friends for their help and support.

BINU CB


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ABSTRACT

Approximately one third of all CO2 emissions due to human activity come from fossilfuels used for generating electricity, with each power plant capable of emitting severalmillion tones of CO2 annually. A variety of other industrial processes also emit largeamounts of CO2 from each plant, for example oil refineries, cement works, and iron and

steel production. These emissions could be reduced substantially, without major changesto the basic process, by capturing and storing the CO2. Other sources of emissions, suchas transport and domestic buildings, cannot be tackled in the same way because of thelarge number of small sources of CO2.

Carbon capture and storage (CCS) is an approach to minimize global warming bycapturing carbon dioxide (CO2) from large point sources such as fossil fuel power plantsand storing it instead of releasing it into the atmosphere CCS applied to a modernconventional power plant could reduce CO2 emissions to the atmosphere byapproximately 80-90% compared to a plant without CCS.


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LIST OF FIGURES

Page no

Fig 1.1 Increase in concentration of CO2 in past two centuries....1

Fig 1.2 Increase in global temperature in past 200 years......1

Fig 1.3 Power plants with and with out CCS....2

Fig 2.1 Three main components of the CCS process3

Fig 2.2 The Esbjerg Power Station, a CO2 capture site in Denmark.3

Fig 3.1 The Gibson coal power plant.. .4

Fig 3.2 Global Distribution of large CO2 sources.5

Fig 3.3 Possible storage sites.5

Fig 4.1 CO2 capture process..6

Fig 4.2 Gas turbine combine cycle with post-combustion7

Fig 4.3 Pre-combustion capture of CO28

Fig 5.1 LPG tanker........9

Fig 6.1.1 Geological storage options.11

Fig 6.2.1 Ocean storage methods..12

Fig 6.2.2 CO2 injected into the deep ocean from oil platforms.........12

Fig 8.1 Geological leakage routes14


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LIST OF TABLES

Table 3.1 Profile by process or industrial activity of worldwide large stationary CO2

Sources with emissions of more than 0.1Mt CO2 per year...4

Table 6.1.1 Storage capacity for several geological storage options.11

Table 6.3.1 Principal metal oxides of Earth's Crust. Theoretically up to 22% of this

mineral mass is able to form carbonates...13

Table 8.1 Costs of energy with and without CCS (2002 US$ per kWh)..15


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NOMENCLATURE

CO2 : Carbon dioxide

CCS: Carbon dioxide Capturing and Storage

ECM: Enhanced Coal bed Methane

EOR: Enhanced Oil Recovery

IEA : International Energy Agency

IPCC: Intergovernmental Panel on Climate Change

LPG: Liquefied Petroleum Gas

MEA: Monoethanolamine

NGCC: Natural Gas Combined Cycle

PC: Pulverized Coal


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CONTENTS

ACKNOWLEDGEMENT

ABSTRACT

LIST OF FIGURES

LIST OF TABLES

NOMENCLATURE

1. INTRODUCTION ......1

2.CARBON DIOXIDE CAPTURE AND STORAGE.33. SOURCES OF CO2 EMISSIONS ....................................................................4

4. CO2 CAPTURE ....6

4.1 Post-Combustion Systems..7 4.2 Pre-Combustion Systems7 4.3 Oxy-Fuel Systems...8

5. CO2 TRANSPORTATION..9

6. CO2 STORAGE (SEQUESTRATION).10

6.1 Geological Storage10 6.2 Ocean Storage...12 6.3 Mineral Storage.13

7. RISK OF LEAKAGE..14

8. COST OF CO2 CAPTURE AND STOREGE OPERATIONS............................15

9. CONCLUSION16

REFERENCES.17


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1.INTRODUCTIONCarbon dioxide (CO2) is a greenhouse gas that occurs naturally in the atmosphere.

Human activities are increasing the concentration of CO2 in the atmosphere thuscontributing to Earths global warming. CO2 is emitted when fuel is burnt be it in largepower plants, in car engines, or in heating systems. It can also be emitted by some other

industrial processes, for instance when resources are extracted and processed, or whenforests are burnt.Currently, 30 Gt per year of CO2 is emitted due to human activities.Theincrease in concentration of carbon in the past two hundred years is shown in the Fig 1.1

Fig 1.1 Increase in concentration of CO2 in past two centuries

Fig 1.2 Increase in global temperature in past 200 years.


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One possible option for reducing CO2 is to store it underground. This technique iscalled Carbon dioxide Capture and Storage (CCS).

In Carbon capture and storage (CCS), carbon dioxide (CO2) is capured from largepoint sources (A point source of pollution is a single identifiable localized source of air,water, thermal, noise or light pollution).such as fossil fuel power plants and storing it

instead of releasing it into the atmosphere. Although CO2 has been injected intogeological formations for various purposes, the long term storage of CO2 is a relativelyuntried.

CCS applied to a modern conventional power plant could reduce CO2 emissions tothe atmosphere by approximately 80-90% compared to a plant without CCS.

Fig 1.3 Power plants with and with out CCS.

The section2 presents the general framework for the assessment together with abrief overview of CCS systems. Section 3 then describes the major sources ofCO2, a stepneeded to assess the feasibility of CCS on a global scale. Technological options for CO2capture are then discussed in Section 4, while Section 5 focuses on methods of CO2transport. Following this, each of the storage options is addressed on section 6. Section6.1 focuses on geological storage, Section 6.2 on ocean storage, and Section 6.3 onmineral carbonation ofCO2 section 7 discus the risk of CO2 leakage, The overall costsand economic potential of CCS are then discussed in Section 8, followed by the

conclusion in Section 9.


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3.CARBON DIOXIDE CAPTURE AND STORAGEOne technique that could limit CO2 emissions from human activities into the

atmosphere is Carbon dioxide Capture and Storage (CCS). It involves collecting, at itssource, the CO2 that is produced by power plants or industrial facilities and storing it awayfor a long time in underground layers, in the oceans, or in other materials

The process involves three main steps:

1. capturing CO2, at its source, by separating it from other gases produced by anindustrial process

2. transporting the captured CO2 to a suitable storage location (typically incompressed form)

3. storing the CO2 away from the atmosphere for a long period of time, for instancein underground geological formations, in the deep ocean, or within certain mineralcompounds.

Fig 2.1 The three main components of the CCS process

Fig 2.2 The Esbjerg Power Station, a CO2 capture site in Denmark


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3. SOURCES OF CO2 EMISSIONS SUITABLE FOR CAPTURE AND STORAGE

Several factors determine whether carbon dioxide capture is a viable option for aparticular emission source:

the size of the emission source, whether it is stationary or mobile, how near it is to potential storage sites, and how concentrated its CO2 emissions are.

Carbon dioxide could be captured from a large stationary emission sources such asa power plants or industrial facilities that produce large amounts of carbon dioxide. Ifsuch facilities are located near potential storage sites, for example suitable geologicalformations, they are possible candidates for the early implementation of CO2 captureand storage (CCS).

Small or mobile emission sources in homes, businesses or transportation are notbeing considered at this stage because they are not suitable for capture and storage.

Fig 3.1 The Gibson coal power plant, a good example of a large stationary source.

Process Number of sources Emissions (MtCO2 yr-1

)

Fossil fuels Power 4,942 10,539

Cement production 1,175 932

Refineries 638 798

Iron and steel industry 269 646

Petrochemical industry 470 379

Oil and gas processing N/A 50

Other sources 90 33

Biomass

Bioethanol and bioenergy 303 91

Total 7,887 13,466

Table 3.1 Profile by process or industrial activity of worldwide large stationary CO2 sourceswith emissions of more than 0.1 MtCO2 per year.


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In 2000, close to 60% of the CO2 emissions due to the use of fossil fuels wereproduced by large stationary emission sources, such as power plants and oil and gasextraction or processing industries (see Table 3.1).

Four major clusters of emissions from such stationary emission sources are: the Midwest and eastern USA, thenorthwestern part of Europe, the eastern coast of China and the Indian subcontinent (see Figure 3.2).

Fig 3.2 Global Distribution of large CO2 sources

Many stationary emission sources lie either directly above, or within reasonable distance(less than 300km) from areas with potential for geological storage (see Fig 3.2 & Fig 3.3)

Fig 3.3 Possible storage sites


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4.CO2 CAPTUREThe purpose of CO2 capture is to produce a concentrated stream of CO2 at high

pressure that can readily be transported to a storage site. Although, in principle, the entiregas stream containing low concentrations of CO2 could be transported and injectedunderground, energy costs and other associated costs generally make this approach

impractical. It is therefore necessary to produce a nearly pure CO2 stream for transportand storage. Applications separating CO2 in large industrial plants, including natural gastreatment plants and ammonia production facilities, are already in operation today.Currently, CO2 is typically removed to purify other industrial gas streams. Removal hasbeen used for storage purposes in only a few cases; in most cases, the CO 2 is emitted tothe atmosphere. Capture processes also have been used to obtain commercially usefulamounts of CO2 from flue gas streams generated by the combustion of coal or natural gas.However, there have been no applications of CO2 capture at large (e.g., 500 MW) powerplants.

Three systems are available for power plants: post-combustion, pre-combustion,and oxy fuel combustion systems. The captured CO2 must then be purified and

compressed for transport and storage.

Fig 4.1 CO2 capture process.


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4.1 Post-Combustion Systems

This system separate CO2 from the flue gases produced by the combustion of theprimary fuel in air. These systems normally use a liquid solvent to capture the smallfraction ofCO2 (typically 315% by volume) present in a flue gas stream in which themain constituent is nitrogen (from air). For a modern pulverized coal (PC) power plant or

a natural gas combined cycle (NGCC) power plant, current post-combustion capturesystems would typically employ an organic solvent such as monoethanolamine (MEA).

Fig 4.2 Gas turbine combine cycle with post-combustion

4.2 Pre-Combustion Systems

In this process the primary fuel in a reactor with steam and air or oxygen toproduce a mixture consisting mainly of carbon monoxide and hydrogen (synthesis gas).Additional hydrogen, together with CO2, is produced by reacting the carbon monoxidewith steam in a second reactor (a shift reactor). The resulting mixture of hydrogen andCO2 can then be separated into a CO2 gas stream, and a stream of hydrogen. If the CO2 isstored, the hydrogen is a carbon-free energy carrier that can be combusted to generate

power and/or heat. Although it is costly than post-combustion systems, the highconcentrations ofCO2 produced by the shift reactor (typically 15 to 60% by volume on adry basis) and the high pressures often encountered in these applications are morefavorable for CO2 separation.


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Fig 4.3 Pre-combustion capture of CO2

4.3 Oxyfuel Combustion Systems

This system use oxygen instead of air for combustion of the primary fuel toproduce a flue gas that is mainly water vapour and CO2. This results in a flue gas withhigh CO2 concentrations (greater than 80% by volume). The water vapour is thenremoved by cooling and compressing the gas stream. Oxyfuel combustion requires theupstream separation of oxygen from air, with a purity of 9599% oxygen assumed inmost current designs. Further treatment of the flue gas may be needed to remove airpollutants and non- condensed gases (such as nitrogen) from the flue gas before the CO2is sent to storage. As a method of CO2 capture in boilers, oxyfuel combustion systems arein the demonstration phase. Oxyfuel systems are also being studied in gas turbine

Current post-combustion and pre-combustion systems for power plants couldcapture 8595% of the CO2 that is produced. Higher capture efficiencies are possible,although separation devices become considerably larger, more energy intensive and morecostly. Capture and compression need roughly 1040% more energy than the equivalentplant without capture, depending on the type of system. Due to the associated CO2

emissions, the net amount of CO2 captured is approximately 8090%. Oxyfuelcombustion systems are, in principle, able to capture nearly all of the CO2 produced.However, the need for additional gas treatment systems to remove pollutants such assulphur and nitrogen oxides lowers the level of CO2 captured to slightly more than 90%.


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5. CO2 TRANSPORTATION

After capture, the CO2 must be transported to suitable storage sites. TodayPipelines operate as a mature market technology and are the most common method fortransporting CO2. Gaseous CO2 is typically compressed to a pressure above 8 MPa inorder to avoid two-phase flow regimes and increase the density of the CO2, thereby

making it easier and less costly to transport. CO2 also can be transported as a liquid inships, road or rail tankers that carry CO2 in insulated tanks at a temperature well belowambient, and at much lower pressures.

The first long-distance CO2 pipeline came into operation in the early 1970s. In theUnited States, over 2,500 km of pipeline transports more than 40 MtCO2 per year fromnatural and anthropogenic sources, and it is mainly used for EOR. These pipelines operatein the dense phase mode (in which there is a continuous progression from gas to liquid,without a distinct phase change), and at ambient temperature and high pressure. In mostof these pipelines, the flow is driven by compressors at the upstream end, although somepipelines have intermediate (booster) compressor stations.

In some situations or locations, transport of CO2 by ship may be economicallymore attractive, particularly when the CO2 has to be moved over large distances oroverseas. Liquefied petroleum gases (LPG, principally propane and butane) aretransported on a large commercial scale by marine tankers. CO2 can be transported byship in much the same way (typically at 0.7 MPa pressure), but this currently takes placeon a small scale because of limited demand. The properties of liquefied CO2 are similar tothose of LPG, and the technology could be scaled up to large CO2 carriers if a demand forsuch systems were to materialize.

Road and rail tankers also are technically feasible options. These systemstransport CO2 at a temperature of -20C and at 2 MPa pressure. However, they areuneconomical compared to pipelines and ships, except on a very small scale, and areunlikely to be relevant to large-scale CCS.

Fig 5.1 An LPG tanker-CO2can be transported in the similar way.


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6. CO2 STORAGE (SEQUESTRATION)

Various forms have been conceived for permanent storage of CO2. These formsinclude gaseous storage in various deep geological formations (including salineformations and exhausted gas fields), liquid storage in the ocean, and solid storage byreaction of CO2 with metal oxides to produce stable carbonates.

6.1 Geological Storage.

Also known as geo-sequestration, this method involves injecting carbon dioxide,directly into underground geological formations. Geological formations are currentlyconsidered the most promising sequestration sites, and these are estimated to have astorage capacity of at least 2000 Gt CO2 (currently, 30 Gt per year of CO2 is emitted dueto human activities). Oil fields, gas fields, saline formations, unminable coal seams, andsaline-filled basalt formations have been suggested as storage sites. Various physical(e.g., highly impermeable caprock) and geochemical trapping mechanisms would preventthe CO2 from escaping to the surface. CO2 is sometimes injected into declining oil fieldsto increase oil recovery (enhanced oil recovery).CO2 storage in hydrocarbon reservoirs or

deep saline formations is generally expected to take place at depths below 800 m, wherethe ambient pressures and temperatures will usually result in CO2 being in a liquid orsupercritical state. Under these conditions, the density of CO2 will range from 50 to 80%of the density of water. This is close to the density of some crude oils, resulting inbuoyant forces that tend to drive CO2 upwards. Fig6.1.1 shows some of the methods usedin geological storage.

This option is attractive because the storage costs may be partly offset by the saleof additional oil that is recovered

Unminable coal seams can be used to store CO2 because CO2 adsorbs to thesurface of coal. However, the technical feasibility depends on the permeability of the coalbed. In the process of absorption the coal releases previously absorbed methane, and themethane can be recovered (enhanced coal bed methane recovery). The sale of themethane can be used to offset a portion of the cost of the CO2 storage.

Saline formations contain highly mineralized brines, and have so far beenconsidered of no benefit to humans. Saline aquifers have been used for storage ofchemical waste in a few cases. The main advantage of saline aquifers is their largepotential storage volume and their common occurrence. This will reduce the distancesover which CO2 has to be transported. The major disadvantage of saline aquifers is thatrelatively little is known about them, compared to oil fields.

For well-selected, designed and managed geological storage sites, IPCC estimatesthat CO2 could be trapped for millions of years, and the sites are likely to retain over 99%of the injected CO2 over 1,000 years.


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Fig 6.1.1 Geological storage options.

Reservoir type Lower estimate of storage

capacity (GtCO2)

Upper estimate of storage

capacity (GtCO2)

Oil and gas fields 675a 900a

Unminable coal seams(ECBM)

3-15 200

Deep saline formations 1,000 Uncertain, but possibly 104

Table 6.1.1 Storage capacity for several geological storage options.


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6.2 Ocean Storage

A potential CO2 storage option is to inject captured CO2 directly into the deepocean (at depths greater than 1,000 m), where most of it would be isolated from theatmosphere for centuries. This can be achieved by transporting CO2 via pipelines or shipsto an ocean storage site, where it is injected into the water column of the ocean or at the

sea floor. The dissolved and dispersed CO2 would subsequently become part of the globalcarbon cycle. Fig 6.1.2 shows some of the main methods that could be employed. Oceanstorage has not yet been deployed or demonstrated at a pilot scale, and is still in theresearch phase. However, there have been small- scale field experiments and 25 years oftheoretical, laboratory and modeling studies of intentional ocean storage ofCO2.

Fig 6.2.1 Ocean storage methods.

Fig 6.1.2 CO2can be injected into the deep ocean from oil platforms.

CO2 injection, however, can harm marine organisms near the injection point. It isfurthermore expected that injecting large amounts would gradually affect the wholeocean. Because of its environmental implications, CO2 storage in oceans is generally nolonger considered as an acceptable option


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6.3 Mineral Storage

Through chemical reactions with some naturally occurring minerals, CO2 isconverted into a solid form through a process called mineral carbonation and storedvirtually permanently. This is a process which occurs naturally, although very slowly.

These chemical reactions can be accelerated and used industrially to artificiallystore CO2 in minerals. However, the large amounts of energy and mined minerals neededmakes this option less cost effective.

Earthen Oxide Percent of Crust Carbonate Enthalpy change

(kJ/mol)

SiO2 59.71

Al2O3 15.41

CaO 4.90 CaCO3 -179

MgO 4.36 MgCO3 -117

Na2O 3.55 Na2CO3

FeO 3.52 FeCO3

K2O 2.80 K2CO3

Fe2O3 2.63 FeCO3

21.76 All Carbonates

Table 6.3.1 Principal metal oxides of Earth's Crust. Theoretically up to 22% of thismineral mass is able to form carbonates.


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7. RISK OF LEAKAGE

The risks due to leakage from storage ofCO2 in geological reservoirs fall into twobroad categories: global risks and local risks. Global risks involve the release ofCO2 thatmay contribute significantly to climate change if some fraction leaks from the storageformation to the atmosphere. In addition, ifCO2 leaks out of a storage formation, local

hazards may exist for humans, ecosystems and groundwater. These are the local risks.

Fig 8.1 Geological leakage routes


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8. COST OF CO2 CAPTURE AND STOREGE OPERATIONS

CCS applied to a modern conventional power plant could reduce CO2 emissions tothe atmosphere by approximately 80-90% compared to a plant without CCS. Capturingand compressing CO2 requires much energy and would increase the fuel needs of a coal-fired plant with CCS by about 25%. These and other system costs are estimated to

increase the cost of energy from a new power plant with CCS by 21-91%.

Natural gas

combined cyclePulverized

coalIntegrated gasification

combined cycle

Without capture(reference plant)

0.03 - 0.05 0.04 - 0.05 0.04 - 0.06

With capture and

geological storage

0.04 - 0.08 0.06 - 0.10 0.06 - 0.09

With capture andEnhanced oil recovery

0.04 - 0.07 0.05 - 0.08 0.04 - 0.08

Table 8.1 Costs of energy with and without CCS (2002 US$ per kWh)


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9. CONCLUSION

Large reductions in emissions of CO2 to the atmosphere are likely to be needed toavoid major climate change. Capture and storage ofCO2, in combination with other CO2abatement techniques, could enable these large reductions to be achieved with leastimpact on the global energy infrastructure and the economy. Capture and storage is

particularly well suited to use in central power generation and many energy-intensiveindustrial processes. CO2 capture and storage technology also provides a means ofintroducing hydrogen as an energy carrier for distributed and mobile energy users.

For power stations, the cost of capture and storage is about $50/t ofCO2 avoided.This compares favorably with the cost of many other options considered for achievinglarge reductions in emissions. Use of this technique would allow continued provision oflarge-scale energy supplies using the established energy infrastructure. There isconsiderable scope for new ideas to reduce energy consumption and costs of CO2 captureand storage which would accelerate the development and introduction of this technology


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REFERENCES

1. Department of Trade and Industry (UK), Gasification of Solid and Liquid Fuelsfor Power Generation, report TSR 008, Dec. 1998

2. Department of Trade and Industry (UK), Supercritical Steam Cycles for PowerGeneration Applications, report TSR 009, Jan. 1999

3. Durie R, Paulson C, Smith A and Williams D, Proceedings of the 5thInternationalConference on Greenhouse Gas Control Technologies, CSIRO(Australia)publications, 2000

4. Eliasson B, Riemer P W F and Wokaun A (editors), Greenhouse Gas ControlTechnologies, Proceedings of the 4th International Conference, Elsevier ScienceLtd., Oxford 1999

5. Herzog H, Eliasson B and Kaarstad O, Capturing Greenhouse Gases, ScientificAmerican, Feb. 2000, 54-61

6. Intergovernmental Panel on Climate Change (IPCC), Climate Change 1995 -TheScience of Climate Change, Cambridge University Press, 1996

7. International Energy Agency, Key World Energy Statistics, 1999 edition.IEAGreenhouse Gas R&D Programme, Transport &Environmental Aspects of CarbonDioxide Sequestration, 1995, ISBN 1 898373 22 1

8. IEA Greenhouse Gas R&D Programme, Abatement of Methane Emissions,June1998, ISBN 1 898 373 16 7

9. IEA Greenhouse Gas R&D Programme, Ocean Storage of CO2, Feb. 1999, ISBN1 898 373 25 6

10.IEA Greenhouse Gas R&D Programme, The Reduction of Greenhouse GasEmissions from the Cement Industry, report PH3/7, May 1999

11.IEA Greenhouse Gas R&D Programme, The Reduction of Greenhouse GasEmissions from the Oil Refining and Petrochemical Industry, report PH3/8, June1999

12.www.ipcc.ch13.

www.Greenfacts.org

14.www.ieagreen.org.uk

17-binu cb-carbondioxide capturing and storage

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