Overview of Techniques and Approaches to CO2 Capture

by Alain Bill

ALSTOM Power

www.ieagreen.org.uk

Presentation to UNECE Carbon Sequestration WorkshopGeneva, 19 November 2002

CO2 Capture Overview

IEA Greenhouse Gas R&D ProgrammeThe need for emission reductions Power generation and capture of CO2

Other sources of CO2

Overview of costsConclusions

IEA Greenhouse Gas R&D Programme

KoreaJapanFranceFinlandDenmarkCECCanadaBelgiumAustralia

VenezuelaUSAUKSwitzerlandSwedenNorwayNew ZealandNetherlands

Sponsors: ALSTOM Power Technology, BP, ChevronTexaco, EniTecnologie, EPRI, ExxonMobil, RWE, Shell, TotalFinaElf

IEA Greenhouse Gas Programme Objectives:

Evaluate technologies for the abatement of greenhouse gas emissionsCommunicate results Develop targets for researchFacilitate R&D and demonstration projects

Tackling climate change Background

Rising levels of greenhouse gases in the atmosphere are changing the climateTo avoid dangerous changes, will need to stabilise greenhouse gas concentrationsIPCC1 has indicated that deep reductions (>60%) will be required in global emissions To stabilise atmospheric concentrations of greenhouse gases, will eventually need zero netemissions

1 Intergovernmental Panel on Climate Change

Technology Options Stabilise atmospheric CO2 levels by

Reducing energy useSwitching to different fuels

Natural gas in place of coalRenewable energy - e.g. wind, biomassNuclear power

Sequestering CO2Enhance natural sinks for CO2

Capture and storage of CO2

Capture and storage of CO2 Overview

Capture and storage could deliver deep reductions in CO2 emissions Uses technology proven in other applicationsComplementary to other mitigation optionsThere is no magic bullet to solve the problem of climate change

Capture and storage of CO2

Power generation post-combustion capture

StorageCO2Separation

N2, H2O to atmosphere

CO2

Fossil fuelcombustion

Flue gases

PowerGeneration

Compression

Post-combustion capture Current status

Power generation: PF and NGCC in general use

CO2 separation: Amine-scrubbing e.g. mono-ethanolamine (MEA)Experience >60 yearsMainly in reducing atmospheresIn use today, capturing CO2 for soft drinks

Emission ReductionCO2 Emissions (kg/kWh)

00.10.20.30.40.50.60.70.8

Natural Gas Coal

Without captureWith capture

Power Generation Efficiency

0

10

20

30

40

50

60

Gas combinedcycle

Pulverised coal

WithoutcaptureWithcapture

%, LHV

Cost of Electricity Generation

012345678

Gas Coal

WithoutcaptureWithcapture

US c/kWh

$2/GJ $1.5/GJ 10% discount rate

Cost of Electricity Generation

012345678

Gas Coal

WithoutcaptureWithcapture

US c/kWh

$1/GJ$5/GJ 10% discount rate

Post combustion capture Amine scrubbing

Could make deep reductions in emissionsIncreases generating costs by 50 - 90%Reduces energy efficiency by 8 -13 % pointsSolvent degrades, especially in oxidising environment

To improve, try changing:Method of capturing CO2

Power generation cycle

CO2 Capture Separation techniques

Solvent Absorption Chemical solvent e.g. MEAPhysical solvent e.g. SelexolTM

CO2 Capture Separation techniques

Solvent Absorption Chemical solvent e.g. MEAPhysical solvent e.g. SelexolTM

Adsorption on a solid Pressure Swing Adsorption (PSA)Temperature Swing Adsorption (TSA)

CO2 Capture Separation techniques

Solvent Absorption Chemical solvent e.g. MEAPhysical solvent e.g. SelexolTM

Adsorption on a solid Pressure Swing Adsorption (PSA)Temperature Swing Adsorption (TSA)

Membranes Solvent assisted membrane demonstrated

CO2 Capture Separation techniques

Solvent Absorption Chemical solvent e.g. MEAPhysical solvent e.g. SelexolTM

Adsorption on a solid Pressure Swing Adsorption (PSA)Temperature Swing Adsorption (TSA)

Membranes Solvent assisted membrane demonstrated

CryogenicsOther concepts

Power Generation Cycles Options

Using established technology:Pre-combustion decarbonisation

New concepts:Alter combustion conditions

Power Generation with Capture Pre-combustion decarbonisation: coal

IGCC with shift

CO2Separation

H2

CO2GasifierCoal

Shift Reactor Storage

GT CC

Air SeparationUnit

O2 N2

Power Generation with Capture Pre-combustion decarbonisation: gas

Combination of known technologies

CO2Separation

H2/N2

CO2Partial Oxidation*

Naturalgas

Shift Reactor Storage

GT CC* or Autothermal reformer

or Steam reformer

Pre-combustion decarbonisation Current status

Based on near-commercial technologyAdditional component = shift reactorGas turbine must be capable of using H2-rich fuelNOx emission control

CO2 separation Physical solvent well established in this type of duty

Power Generation with Capture Alter combustion conditions

Recycle CO2 or H2Oor Partial recycle of CO2

CO2 or H2O

StorageCO2

Air SeparationUnit

O2

SeparationFossil fuelcombustion

PowerGeneration

Altered combustion conditions Current status

Research currently in Canada, Japan, etcFocussed mainly on boilers

Partial recycle - doubles CO2 concentrationCO2 separation - solvent absorption

Full recycle Produces concentrated CO2 streamCO2 separation - essentially removal of waterRequires ASUSubstantial development work required

*Natural gas at 2$/GJ, 10% discount rate

Post combustion

Partial recycle

Cost of avoidance($/tCO2)

32 3929

Precombustion

Efficiency (lhv) 48% 48%47%

Cost of electricity (c/kWh)* 3.1 3.43.2

Economics of capture Gas-fired plant

Additional generating costs

Gas @ $2/GJ Coal @ $1.5/GJ

Gas Coal CoalPost combustion Pre-combustion

c/kWh

0

1

2

3

Transport/storage

Captureplant

Powerplant

Fuel

Other Potential Applications Capture and storage of CO2

Power generationThe “conventional” application

Major energy using industrye.g. Oil refining

Manufacture of decarbonised fuel for transporte.g. H2 from natural gas

Conclusions CO2 capture and storage

Can be delivered using known technologyWould make deep reductions in emissionsCost comparable with other options

Conclusions CO2 capture and storage

Can be delivered using known technologyWould make deep reductions in emissionsCost comparable with other options

Opportunities for actionReduce cost to encourage early applicationDemonstrate full-scale applicationEnsure minimal environmental impactVerify amount of CO2 stored