co2 emission comparison wp3 final english

8/4/2019 Co2 Emission Comparison WP3 Final English

1/30

Carbon Dioxide Capture from Coal-FiredPower Plants in China

Summary Report for NZEC Work Package 3September, 2009

Preparedby:

DoosanBabcockEnergyLimited JacquelineGIBSONandDiemoSCHALLEHN

TsinghuaUniversity,

DepartmentofChemicalEngineeringZHENGQueandCHENJian

TsinghuaUniversity,

DepartmentofThermalEngineering, Key

LaboratoryforThermalScienceandPower

EngineeringofMinistryofEducation

WANGShujuan

GreengenCo.Ltd,Beijing CAOJiang

ImperialCollegeLondon,

MechanicalEngineeringDepartment,

EnergyTechnologyforSustainable

DevelopmentGroup

JonGIBBINSandMathieuLUCQUIAUD

NorthChinaElectricPowerUniversity,KeyLabofConditionMonitoringandControl

forPowerPlantEquipmentofMinistryof

Education

YANGYongping,XUGangandDUANLiqiang

TsinghuaUniversity,BPCleanEnergy

Research&EducationCentreXUZhaofeng

WuhanUniversity HUJicaiandLIJi

ZhejiangUniversity,StateKeyLaboratoryof

CleanEnergyUtilization

FANGMengxiang,YANShuipingandLUO

Zhongyang


2/30

ii

050

100150200250

300350400

Advanced

supercrit

800MW

Oxyfiring Postcom

MEA

Postcom

aqueous

ammonia

Precom

IGCC

Precom

polygen

Existing

600MW

supercrit

Postcom

MEA

Postcom

aqueous

ammonia

Existing

300MW

subcrit

Postcom

MEA

Postcom

aqueous

ammonia

0

200

400

600

800

1000

Advanced

supercrit

800MW

Oxyfiring Postcom

MEA

Postcom

aqueous

ammonia

Precom

IGCC

Precom

polygen

Existing

600MW

supercrit

Postcom

MEA

Postcom

aqueous

ammonia

Existing

300MW

subcrit

Postcom

MEA

Postcom

aqueous

ammonia

0

5000

10000

15000

20000

Advanced

supercrit

800MW

Oxyfiring Postcom

MEA

Postcom

aqueous

ammonia

Precom

IGCC

Precom

polygen

Existing

600MW

supercrit

Postcom

MEA

Postcom

aqueous

ammonia

Existing

300MW

subcrit

Postcom

MEA

Postcom

aqueous

ammonia

0

10

20

30

40

50

Advanced

supercrit

800MW

Oxyfiring Postcom

MEA

Postcom

aqueous

ammonia

Precom

IGCC

Precom

polygen

Existing

600MW

supercrit

Postcom

MEA

Postcom

aqueous

ammonia

Existing

300MW

subcrit

Postcom

MEA

Postcom

aqueous

ammonia

NetEfficiency

(%L

HV)

CostofElectricity

(RMB/MWh)

Power plant net efficiencies with and without CO2 capture

Cost of electricity with and without CO2 capture, 85% load factor, 10% discount rate, tax not includedCoal costs: 16 RMB/GJ / 32 RMB/GJ

Capital expenditure

CAPEX = Total Installed Cost + 10% contingency + 7% owners costs, financing costs and taxes not included

Relativetonewbuildadvancedsupercritical

pulverisedcoalplant

Relativeto

existing600MW

supercritical coal

plant

Relativeto

existing300MW

subcritical coal

plant

CAPEX(RMB/kW)

CostofAbat

ement

(RMB/tCO2)

Cost of abatement

ExecutiveSummary

ThisreportdrawsonthecaptureplantcasestudiesbyNZECWorkPackage3partnerstopresent,in

aunifiedandconsistent form,the technicalandeconomicperformanceofpowergenerationwith

CO2 capture in China. Complementary work on performance calculations by Chinese and UK

partnershasbeencombinedwhereappropriatetogiveestimatedfinaloverallplantefficienciesand

CO2emission levels. Estimatedcapitalcostshavebeenusedtoderive levelisedcostsofelectricity

andemissionabatementcostsonaconsistentbasis.

Advancednewbuildcapturetechnologiesthathavestilltobedemonstrated,oxyfiring,post

combustionwithaqueousammoniaandprecombustioncaptureonIGCC,arepredictedtoachieve

similarpowerplantefficienciesof35.6,35.7and36.8%respectively. CAPEXvaluesfortheseplants

areapproximately9000to10000RMB/kWnet,withanestimated+/ 30%uncertainty. Levelised

costsofelectricityfortheseoptionsareestimatedtohavearangeofapproximately370410

RMB/MWhforacoalcostof16RMB/GJandapproximately40%higherforacoalcostof32RMB/GJ.

Costsofabatementarecalculatedrelativetothestandardalternativeplantthatwouldbebuilt,an

advancedsupercriticalplant. Sincethecostofabatementisbasedonthedifferencesbetweenrelativelylargernumbersthereismorevarianceintheresults,fromanestimated140RMB/tCO2for

oxyfiringto200RMB/tCO2forIGCC+CCS. Thesevaluesare,however,verysensitivetoestimatesfor

captureplantcosts,particularlytheadditionalcapitalcosts,andshouldberegardedaspreliminary.

PostcombustioncapturewithanMEAbased solvent,anolder technology, ispredicted tohavea

generally less favourableperformance.Polygenerationofelectricityandmethanolalsoappears to

havealowefficiencyandhighcapitalcosts,butthemethanolproductionisnottakenintoaccount.


3/30

iii

Table of contents1.Backgroundandsupportingcasestudyreports 1

1.1Backgroundandscope 1

1.2Contributingreports 1

2. PowergenerationfromnewbuildpulverisedcoalplantswithCCS(DB,DCE,DTE,IMP,NCEPU,ZJU) 2

2.1Advancedsupercriticalbaseplantfornewbuildcasestudieswithandwithoutcapture 2

2.2CO2captureusingoxyfiring(DB,ZJU) 5

2.3 Post-combustion CO2 capture (DCE, DTE, IMP, NCEPU, ZJU) 6

2.3.1 MEApostcombustioncapturesystem(DCE) 6

2.3.2Aqueousammoniapostcombustioncapturesystem(DTE) 7

2.3.3Thermalintegrationbetweenthepowerplantsteamcycleandpostcombustioncaptureunitsandcalculationofoverallplantefficiencyandcostwithcapture(DCE,DTE,IMP,NCEPU,ZJU) 8

3. PostcombustioncapturefromexistingChinesepowerplants(NCEPU) 11

3.1Chinese600MWsupercriticalunit 11

3.2Chinese300MWsubcriticalunit 11

3.3PerformancewithoutandwithCO2capture 11

4. ElectricpowergenerationwithprecombustionCO2capture(GG,THCEC) 12

4.1Background 12

4.2GS1 2400MWIGCCusingTPRIgasifierwithCCS(GG) 14

4.3GS2 1400MWpolygenerationsystemwithCCS(THCEC) 15

5. SummaryofCO2captureperformancefordifferentplanttypes 17

AppendixACasestudybasis 21

AppendixBTabulatedsummaryoftechnicalandeconomicperformance 23ofcoalfiredpowerplantswithCO2captureunderChineseconditions

AppendixC CO2captureusingmembranegasabsorptiontechnology 24

AppendixD LevelisedcostoftransportingCO2asafunctionofmassflowrate 26


4/30

1

1.Backgroundandsupportingcasestudyreports

1.1 Background and scope

ThisreportdrawsonthefollowingcaptureplantcasestudiesbyNZECWorkPackage3partners.

Salientfeaturesofthesestudiesarepresentedinthissummaryreportbutfordetailedinformation

readersshouldrefertotheoriginalsource(s). Theseareindicatedinthetextbytheappropriate

partnerabbreviationsshowninbracketsaftersectionheadings.

Theprincipalpurposeofthisreportistopresentinaunifiedandconsistentformthetechnicaland

economicperformanceofthemaincapturecasestudies. Complementaryworkonperformance

calculationsbyChineseandUKpartnershasbeencombinedwhereappropriatetogivefinaloverall

plantefficienciesandCO2emissionlevels. Estimatedcapitalcostshavebeenusedtoderivelevelised

costsofelectricityandemissionabatementcostsonaconsistentbasis. Thesearepresentedin

graphicalandtabulatedforms.

1.2 Contributing NZEC Work Package 3 Reports

Partner

Abbreviation

FullName ReportTitle

DB DoosanBabcockEnergyLimited JRGibsonandDSchallehn, ChinaUKNear

ZeroEmissionsCoal(NZEC)Oxyfiring

Options

DCE TsinghuaUniversity, Departmentof

ChemicalEngineering

QueZhengandJianChen,Costestimationfor

CO2CapturewithaMEAabsorptionprocess

DTE TsinghuaUniversity,Departmentof

ThermalEngineering, KeyLaboratory

forThermalScienceandPower

EngineeringofMinistryofEducation

WangShujuan,CarbonDioxideCaptureUsing

MDEAandAmmoniaSolutions

GG GreengenCo.,Ltd,Beijing CaseStudyforIGCCPowerPlantInChina

(withCCS)

IMP ImperialCollegeLondon,Mechanical

EngineeringDepartment,Energy

TechnologyforSustainable

DevelopmentGroup

MathieuLucquiaud, Steamcyclecalculations

forcapturereadysteamcycleandretrofits

withMEA,ammoniaandMDEAsolvents

NCEPU NorthChinaElectricPowerUniversity,

KeyLabofConditionMonitoringand

ControlforPowerPlantEquipmentof

MinistryofEducation

YongpingYang,GangXuandLiqiangDuan,

CarbonDioxideCapturefromExistingCoal

FiredPowerPlantinChina

THCEC TsinghuaUniversity,BPCleanEnergy

Research&EducationCentre

XUZhaofeng, Polygenerationusingtwo

stageslurrygasifierwithCCS

WHU WuhanUniversity HuJicaiandLiJi,CO2Transport

ZJU ZhejiangUniversity,StateKey

LaboratoryofCleanEnergyUtilization

MengxiangFang,ShuipingYanand

ZhongyangLuo,CarbonDioxideCapturefrom

aNewbuiltUltraSupercriticalPCPowerPlant


5/30

2

UsingHollowFibreMembraneContactors

2. PowergenerationfromnewbuildpulverisedcoalplantswithCCS(DB,DCE,

DTE,IMP,NCEPU,ZJU)

2.1 Advanced supercritical base plant for new build case studies with and withoutcapture (DB)

Newbuild, pulverised coal (PC) capture studies are based on Advanced Supercritical (ASC) Boiler

Turbine (BT) technology. Advanced supercritical boilers are already operating in China, with an

estimated Total Installed Cost of 5000 RMB/kW based on Chinese partners experience. Present

stateoftheart advanced supercritical boiler/turbine technology is used, with steam turbine inlet

conditionsof280bar/ finalsuperheat temperatureof600C/ final reheat temperatureof610C,

givinganefficiencyforthesiteandcoalsspecifiedof43.9%LHVnet. Emissionscontrolsconsistof

DeNOx,particulateremovalandDeSOxplant. Aunitwithanoutputof824.3MWnetisusedasthe

base case fornew build pulverised coaloptions with capture. This size ofunit is typical fornew

advanced supercriticalboilers planned in Europe and alsogives PC capture options with net MW

outputsthatareclosetothelimitingsizeforIGCC+CCSoptions. LargerPCbaseunits(e.g.10001200

MW)arefeasibleandarelikelytobebuiltinChina,buttheoutputoftheIGCC+CCSunitislimitedby

thesizeofthelargestgasturbinesavailable.

AblockflowdiagramforthebasecaseASCPCplant isshown inFigure21. Abriefdescriptionof

eachoftheunitsidentifiedintheblockflowdiagramisgivenbelow,withasubsectionaddinghow,if

atall,itmightneedtobemodifiedforuseinaPCbasedcaptureplant. Thebasecaseunitburnscoal

inairandsoalsodothepostcombustioncapturecases;thebaseplantdesignremainsessentially

unmodified for theseapart from theTurbine Island. Foroxyfiringcapture, thecoal isburntusing

oxygen insteadofair,mixedwith recycledcombustionproductsat theburners tomoderate flame

temperatures. Foroxyfiringcapturecertainaspectsofsometheunits inthebaseplantdesignwill

havetobechangedwhileotherswouldbeusedunaltered,asindicated.

Boiler:Theadvancedsupercriticalboiler isbasedonthestateoftheartDoosanBabcockTwoPass

single reheat BENSON boiler with Posiflow Technology, Balanced Draught, and Gas Biasing for

reheatsteamtemperaturecontrol.

Coalandashhandling:Aconventional system isemployed,withthedesignofthefurnacebottom

ash and fly ash systems from the boiler and downstream particulate removal systems following

modern conventional air fired power generation plant practice which aims to minimise tramp air

ingress.

PulverisedFuelMillingPlant: Coalwillbemilledusingconventionalpulverisers. Inthiscase,tube


6/30

3

mills are selected to pulverise the coal to a suitable fineness (typically >80% passing through

75microns). Ifthecoalsareinclinedtowardssubbituminouscoalsthenrollerorballmillscouldbe

substituted.

Modifications

for

capture

cases: Inanypulverisedfuelcombustionplantwithadirectfiringsystem

the primary gas supplied to the mill is required to both dry the asfired coal and to convey the

pulverisedcoalfromthemilltotheburners. Inthecaseofairfiring,hotcombustionairissupplied

from theair/gasheater,and in the caseofoxyfiring, fluegas is recycled from theFGDoutletand

passesthroughagas/gasheater. Theabilityoftheprimarygastodrythefuelisdrivenbytwofactors,

theoveralltemperatureandheatcapacityofthegasenteringthemill,and itsmoisturecontent.In

bothoxyfiringandair firingthetemperatureoftheprimarygas issimilar,althoughthevolumetric

heat capacity of recycled flue gas is greater than that of air due to the higher density of CO2

comparedtonitrogen.Whenoperatinginairfiringmodethemoistureinthecombustionair(i.e.its

relativehumidity) is low,making thedryingprocesseasierastheairhasahighcapacity toabsorb

evaporatingmoisture. Foroxyfiringoperationtherawrecycledfluegastypicallyhasasubstantially

highermoisturecontentwhich limits thedrying capacity.This reduction indrying capacity canbe

mitigatedbybothincreasingthemilloutlettemperature(althoughtherearepracticallimitstothis)

andbyreducingthemoisturecontentoftherecycledfluegas.

TurbineIsland: Stateoftheartadvancedsupercriticalturbinetechnologywillbeutilized.

Modificationsforcapturecases: Thiswillbeusedwithoutmodificationfromtheairfiringdesignfor

oxyfiring, but with provision for steamextractionafter the intermediatepressure (IP) cylinder for

postcombustioncapture (see section2.3.3below). Rejectedheat from the captureequipment is

usedtominimisethesteamextractionforfeedwaterheatingforallcaptureoptions.

DeNOx: New build plant is required to meetNOx emissions regulations (450mg/Nm3 @ 6%O2).

TechnologiesbasedonprimaryNOxreductionmeasures,(lowNOxburnersandoverfireair (OFA)),

andsecondarymeasures,(SelectiveCatalyticReduction(SCR)),canbeused.

Modificationsforcapturecases: DeNOxplantisnotarequirementwithintheoxyfiringboilerisland

astheNOxiscapturedinthedownstreamcompressionplant. However,DeNOxplantwillneedtobe

installedforpostcombustioncapturecaseswithairfiring.

ESP:Particulateremovalplantisessentialtobothmeetdustemissionlevellimits,asdefinedbythe

applicable environmental legislation, and to protect downstream flue gas fans and blowers from

excessiveerosion.ElectrostaticPrecipitators(ESP)areusedintheNZECbasecase.

Modifications forcapturecases: Whenoperating inoxyfiringmode theparticulateremovalplant

ensuresthattheFGRstreamsarerelativelydustfree.Theproposedoxyfiringandpostcombustion


7/30

4

plants both also utilise an ESP. Previous studies have shown that, as a direct result of the

performanceoftheairheater/gasgasheatermodule,theoperatingtemperatureoftheelectrostatic

precipitator (ESP) is increased during oxyfiring operation to typically between 160C and 200C.

Normally higher temperatures lead to less gas residence time in the ESP with a resulting loss in

particulatecollectionefficiency. However,oxyfiring fluegashasahigherdensitythanairfired flue

gasandthismitigatesthelossinefficiencyarisingfromtheincreasedtemperature.

DeSOx: ForairfiringanFGDisrequiredtomeetemissionslegislation.

Modificationsforcapturecases: Particularattentionwillbegiventoachievingaveryhighlevelof

removal(


8/30

5

2.2 CO2 capture using oxyfiring (DB, ZJU)

Overall,thekeyfeaturesofoxyfiring vsairfiringare:

IncorporationofanairseparationunitforremovalofN2tosupplyanearlypureO2stream

intotherecycledfluegasforthecombustionprocess.

Recirculationoffluegasbacktotheboiler(viaanFGDfortheNZECcoals)providinga

transportmediumforthepfandtomaintaintheradiativeandconvectiveheattransfer

characteristicsofthefurnaceandboiler.

Incorporationofgasgasheatersinsteadofconventionalairpreheatingarrangements.

Incorporationofafluegascoolerandcondensertorecoverheatintothesteamcycle

condensateandfeedwaterpreheatingsystems.

CO2compressionandinertsseparationplant,incorporatingadditionalsulphurremoval

Thisisconsideredalowriskapproachforanoperatorneedingtobeabletomaintainelectrical

outputbecausetheplantdesignsretainfullairfiringcapability,minimisingcommercialandtechnical

riskshouldtheoxyfiringcomponentsbeunavailable,byallowingcontinuedgenerationifthe

oxyfiringplantisoutofservice. Itisenvisagedthatanairfiringcapabilitywillonlybeappliedtothe

initialdemonstrationplants,however,astherearesignificantcostsassociatedwithretainingthison

anoxyfiringplant.


9/30

6

Thisconfigurationthusoffersanevolutionaryapproachfromwellknownandunderstoodplant:

Theplantisdesignedwithoperationalandpracticalexperienceofairfiring.

Similaritiesindesignandoperationtoconventionalairfired,pulverisedcoalpowerplants

foreachofthemajorplantsystemsandcomponents.

Newplantsystems(ASU,compressors)andcomponentsarewellprovendesignsand

commerciallyavailableattherequiredcapacities.

TheoxyfiringcasestudybyDoosanBabcockhasshownthatforanadvancedsupercriticalpower

plantdesignedtocaptureCO2thepenaltyintermsofcycleefficiencyis8.3percentagepoints

comparedwithanairfiredcasewithnoCO2capture,givingafinalefficiencyof35.6%LHVnet.This

penaltyhasbeenmitigatedbyrecoveringheatwithinthesystemtooffsettheadditionalpower

consumptionoftheCO2compressionplantandairseparationunit. Anapproximateestimateisthat

capitalcostsforsuchanoxyfiringplantwillbe48%higheronaRMB/kWbasisthanfora

conventionalairfiredplant(butbasedonUKexperience,ratherthandirectChinesemarketcosting),

givingaTotalInstalledCostof7390RMB/kWforanassumedbaseplantTIC(basedonestimates

fromChinesepartners)of5000RMB/kW. UnlikepostcombustionCO2capturesystems,oxyfiring

plantsdonotneedtomakeupanyCO2capturesolventlosses,sothisfairlysignificantcontribution

torunningcostsisavoided.

2.3 Postcombustion CO2 capture (DCE, DTE, IMP, NCEPU, ZJU)

PostcombustionCO2capturebasedontheuseofmonethanolamine(MEA)solutionswasstudiedin

conventional packedabsorbercolumns(DCE)andinmembranecontactors(ZJUalsoseeAppendix

C). Whilethelatterofferpotentialadvantagesforgasandsolidshandling,theselectedmembrane

materialswerelimitedtomorediluteMEAsolutions(20%w/w)thanthepackedcolumns(30%w/w).

Thismeantthattheperformanceofthemembranesystemwasworseandthereforenoresultsare

reportedinthedetailedcostcomparison;additionalworkisneededonthisnovelapproachifitisto

havethepotentialofbecomingcompetitivewithotheroptions. Similarly,theuseof

methyldiethanolamine(MDEA)inaconventionalpackedcolumn,examinedbyDTE,isalsonot

reportedinthissummarysinceitdidnotappeartoofferanysignificantadvantageoverMEA.


10/30

7

TheuseofaqueousammoniaasaCO2solventwasalsostudiedbyDTE. Whilestillrequiringfurther

developmentworkthisapproachappearstohavethepotentialtooffersignificantadvantagesin

termsofreducedenergypenaltyandcapitalcosts. Ithasthereforebeenincludedinthecomparative

analysisasapossibleexampleofthebenefitsthatimprovedpostcombustioncapture,usingthisor

othersecondgenerationsolvents,maybeabletodeliver,comparedwithplantsusingdesignsbased

ontheindustrystandardMEAsolvent.

2.3.1 MEApostcombustioncapturesystem(DCE)

AschematicflowdiagramfortheMEAcaptureprocessisshowninFigure22.

Figure22 ProcessflowdiagramforMEAcapture

TheconventionalMEAprocessisatemperatureswingabsorptionprocess.TheremovalofCO2from

fluegasisachievedbycontactingthefeedfluegasinanamineabsorberwithanaqueoussolutionof

analkanolamineatalowtemperature,wherethecarriersolution,anaqueousaminesolution

absorbsCO2toformcarbamateorbicarbamateionsandbecomeaCO2richsolution.Meanwhile,

CO2isremovedfromthefluegas.Inasolventregenerator,theCO2richsolutionthenliberatesthe

dissolvedCO2atanelevatedtemperaturetoreversetheabsorptionreactionandbecomesalean

solution.AhighpurityCO2streamisreleasedfromthesolventregeneratorandisthencompressed

to110atmospheres.TheregeneratedCO2leanaminesolutionisthencooledandrecycledtothe

amineabsorberfromthesolventregeneratorforfurtherCO2removal. Boththermalenergyand

electricalenergy,thelatterprincipallyforsolventpumping,fluegasblowersandCO2compression,

arerequiredtoruntheMEAcaptureprocess. Inthisstudyastandardvalueof150kWhpertonneof

CO2capturedisestimatedtoberequiredfortheelectricalenergyinput.


11/30

8

2.3.2Aqueousammoniapostcombustioncapturesystem(DTE)

AsshowninFigure23asimilarflowdiagramisusedforpostcombustioncaptureusingaqueous

ammoniasolutionsbut,becauseofthevolatilityoftheammonia,acondensermustbeprovided

insidethestripper.Theleansolutionfromthestripperiscooledbytherichsolutionandfurtherin

anexternallycooledheatexchangerinordertoreachthedefinedabsorberinlettemperature.In

addition,becauseofthevolatilityofammonia,theN2leavingtheabsorptioncolumnandtheCO2

leavingthedesorptioncolumnwillcontainsomeNH3. Additionalwaterwashingcolumnsareused

toabsorbthisNH3.

The CO2 absorber for ammonia capture is similar to SO2 absorbers (i.e. flue gas desulphurisation

plants FGD)and isdesignedtooperatewithaslurryfeed.Thefluegasflowsupwards incounter

current to the slurry containing a mix of dissolved and suspended ammonium carbonate and

ammoniumbicarbonate;90%oftheCO2fromthefluegasiscapturedintheabsorber.TheCO2rich

slurry from the absorber contains mainly ammonium bicarbonate as the dispersed solids, which

dissolves as the temperature increases in the heat exchanger to about 80C before it enters the

stripper.

Figure23Processflowdiagramforaqueousammoniacapture


12/30

9

2.3.3Thermalintegrationbetweenthepowerplantsteamcycleandpostcombustioncaptureunits

andcalculationofoverallplantefficiencyandcostwithcapture(DCE, DTE, IMP, NCEPU,

ZJU)

Effectiveintegrationbetweenthebasepowerplantandthepostcombustioncaptureequipmentis

essentialtokeeptheefficiencypenaltytoaminimum. AsshowninFigure24,lowpressuresteam

forsolventregenerationisextractedfromthecrossoverpipebetweentheintermediatepressure(IP)

andlowpressure(LP)turbinecylindersandheatrecoveredfromthecaptureplant(principallyfrom

initialCO2cooling)andfromtheCO2compressorintercoolersisrecoveredandusedforcondensate

heat(avoidingtheneedtoextractsteamfromtheLPturbine).

Thesteamturbineshavebeendesignedwithanintermediatepressure(IP)turbinecapableof

operatingwithafloatingoutletpressure,adesignthat(withslightlydifferentmodifications) is

suitableforbothcapturereadysteamplantsandnewbuildpowerplantsthatarecapableofflexible

operation. AfloatingIPturbinehastheadvantageofavoidingthethrottlinglossesofacontrolled

extractionsystemwithavalveattheLPturbinewhentheplantisoperatingwithcapturewhilenot

affectingtheplantefficiencywithoutcapture.TheIPturbineoutletpressureishigherthanthe

operatingpressureofthesolventreboilerwhentheplantdoesnotcaptureCO2.WhenCO2is

capturedsteamisextractedandsenttothesolventreboilertheIPoutletpressuredropstothe

pressurerequiredtofeedthesolventreboiler.

LPsteamextractionforfeedwaterheatingisreducedto10%ofthenoncapturevaluebyheating

boilercondensateusingheatrecoveredfromcoolingtheCO2afterthestripperandcompressor

stages. CalculatedpowerplantperformancewithoutandwithCO2captureisshowninTable21

below.

Tocalculatetheperformanceofthenewbuildpostcombustioncapturecasesthebasecase

advancedsupercriticalplantwasassumedtobemodifiedslightlytooperatewiththesteamcycle

showninFigure24. WhenthesteamrequiredforoperatingtheCO2captureplants,determinedby

modellingthecapturesystemsdescribedin2.3.1and2.3.2(andinmoredetailinDCEandDTEcase

studyreports)isextractedfromthesteamcycle,andalsotakingintoaccounttheheatrecoveryfrom

thecaptureandcompressionprocessesforcondensateheating,thepoweroutput(calculatedusing

gPROMSmodelsasdescribedintheImperialreport),fallstothevaluesshowninTable21below.

AdditionalelectricalpowertorunthecaptureplantsfansandpumpsandtheCO2compressors,

calculatedfromthespecificvaluespertonneofCO2captured foundinthecasestudies,hasalsoto


13/30

10

besubtractedtogivethereducedcaptureplantnetoutputsandnetefficienciesshowninTable21

below.

Table21Performanceofnewbuildadvancedsupercriticalpowerplant

without/withpostcombustionCO2capture

andprincipalenergyrequirementassumptions

Solvent MEA NH3

WITHOUTCAPTURE

Netplantpoweroutput(MWe) 824.3 824.3

Efficiency(%LHVnet) 43.9 43.9

IPturbineoutletpressure(bara) 9.34 25.53

WITHCAPTURE

IPturbineoutletpressure(bara) 4.17 12.57

Solventreboilersteampressure(bara) 3.67 12.06

Heatforsolventregeneration(MJ/kgCO2) 3.54 3.23

Turbineoutputpowerloss(MWe) 116.0 129.1

Captureandcompressionelectricity

requirements(kWh/tCO2)

150 43.4

Capture/compressionplantpowerconsumption

(MWe)

86.1 25.0

Netplantpoweroutput(MWe) 621.5 670.3

Efficiency(%LHVnet) 33.1 35.7


14/30

11

1

1

2

2 0

0

HPIP

condenser

LP LP

Heatrecoveryfrom

captureprocess

Solventreboiler

Desuperheater

Floatingpressure

Relocatedeaerator

steamextraction

3

3

4

4

Figure24 Steamturbine/captureplantintegrationwithafloatingintermediatepressureturbine

Themainadditionalassumptionsandestimatingproceduresforpostcombustioncaptureplant

capitalcostsareshowninthesummaryoftechnicalandeconomicperformanceinAppendixB. The

assumedadditionalchargesforthecaptureandcompressionequipmentandthe,relativelyminor,

modificationstothebaseplantarebasedontheNCEPUcasestudyresults. Aconservative

assumptionhasbeenmadethatthesecaptureandcompressionequipmentcosts(expressedas

RMB/kWthermal)willbethesameirrespectiveofthebaseplantsize(acrosstherangecoveredin

WP3),becauseofuncertaintiesregardingtheactualsizeoftheindividualabsorbersandstrippers

thatcouldbeused(currentlyconsideredtobelimitedto300400MWelectricaloutputequivalent).

Iflargercaptureequipmentunitsizesprovetobefeasibleinthefuturethensomeconsequent

economiesofscalewouldbeexpected,althoughtheeffectonoverallplantcostswouldbelimited

sincethecaptureequipmentitselfisestimatedtobeonly2025%ofthetotalpowerplantcapital

costwithCO2capture.


15/30

12

3. Post combustioncapturefromexistingChinesepowerplants(NCEPU)

InordertoevaluatetheimpactofCO2captureonexistingpulverisedcoalfiredChinesepower

stations,thecostandperformanceof600MWesupercriticaland300MWesubcriticalPCpower

plantswith90%CO2captureandcompressionusingMEAandaqueousammoniawerealso

estimated2.

3.1 Chinese 600MW supercritical unit

Theexampleplantusedasareference600MWsupercriticalunitforthiscasestudywasNo.1unitof

GuiGangpowerplant,locatedatGuangxi,PRChina. Thesteamgeneratorintheseplantsisa

tangentiallycoalfired,supercriticalpressure,controlledcirculation,andradiantreheatwallunit,

designedtogenerateabout1677.5t/hofsteamatnominalconditionsof24.2MPaand566Cwith

reheatsteamheatedto566C.Theunitisconfiguredinaconventionaltypedesignandis

representativeinmanywaysofalargenumberofcoalfiredunitsinusethroughoutbothChinaand

worldwidetoday.

3.2 Chinese 300MW subcritical unit

No.2unitofDaqipowerplantwasusedasareference300MWsubcriticalunit.TheDaqipulverised

coalpowerplantislocatedinNeimengguprovince,PRChina. Theunitisdesignedtogenerateabout

935t/hofsteamatnominalconditionsof16.7MPaand537Cwithreheatsteamheatedto537C.

3.3 Performance without and with CO2 capture

MEAandaqueousammoniatechnologyidenticaltothatusedfornewbuildcapturecaseswas

assumedtoberetrofittedtotheexistingplants. CalculatedperformancewithoutandwithCO2

captureisshowninTable31. Thecaptureefficiencypenaltyforthe600MWsupercriticalplantis

estimatedtobeslightlyhigherthanthatforthe300MWsubcriticalpowerplantwithasimilarCO2

captureprocess.Comparedto300MWsubcriticalunitsthe600MWsupercriticalunitshavehigher

steamtemperaturesandpressuresandhenceasmallersteamflowrateperMWgenerated.When

theCO2captureprocessisretrofittedthedecreaseinsteamflowwillthereforeberelativelylarger

forthesupercriticalplant,resultinginworseoperatingconditionsinthelowpressurecylinderofthe

steamturbine.

2

Amorespecialisedcase,inwhichanexistingsubcriticalpowerplantisrebuilttouseadvancedsupercriticalsteamconditionsandalsoconvertedtooxyfiringcaptureatthesametime,isdescribedintheDoosanBabcock

oxyfiringcasestudyreport.


16/30

13

Table31EstimatedperformanceforexistingPCplantswith90%CO2capture

600MW

no

capture

600MW

MEA

capture

600MW

ammonia

capture

300MW

no

capture

300MW

MEA

capture

300MW

ammonia

capture

Netoutput,MWe 574.09 398.01 435.61 295.13 202.42 225.23

NetPlantLHV

Efficiency(%)40.28 27.93 30.56 38.15 26.17 29.12

Efficiencypenalty

(%points) 12.35 9.72 11.98 9.03

4. Electricpowergenerationwithpre combustionCO2capture(GG,THCEC)

4.1 Background

Precombustioncapturetechnologyisbasedoncoalgasificationandmaybeimplementedasan

IntegratedGasifierCombinedCycle(IGCC)plantforelectricityproductiononlyorasapoly

generationsystem(forexample,hydrogenelectricitycoproduction,methanolelectricity

coproduction). Inallsuchsystems,thecoalwillfirstreactwithoxygentogeneratesyngaswhich

mainlyconsistsofCOandH2,andthentheCOinthesyngaswillbeconvertedintoCO2andH2ina

shiftreactor.ThemixtureofCO2andH2isrelativelyeasytoseparatebecauseitisathighpressure.

Precombustioncapturetechnologyhasthemeritofimposingalowerenergypenaltyandcapital

costincreasethanpostcombustioncapturewhencaptureisimplemented,butdoesrequirea

gasifierbasedpowerplant,whichcurrently,forpurepowergeneration,ismoreexpensivethana

pulverisedcoalpowerplantinChina.

InrecentyearsChinahasbuiltmanycoalgasificationprojects,mainlyforcoaltooil,coaltochemical

andpolygenerationconversionplants.AccordingtoarecentTHCECstudy,thereareapproaching

100largescalegasiferscurrentlyinoperationinChina. MostofthesearelicensedShellorGE

gasifiers,but4unitsaredomesticallydesignedslurryfeedgasifiers.In2005,Chinabuiltamethanol

electricitypolygenerationsysteminShandongprovince.Thepolygenerationprojectproduces

240,000tonnes/yrmethanoland60MWelectricityandhasbeensupportedbyaMOST863

programfordemonstratingdomesticslurrygasifiers.IGCCandprecombustionCO2capture

technology(basedonIGCC)arenowunderdevelopmentinChina.In2004,ChinaHuanengGroup

(CHNG)announcedtheGreenGenprojectandfoundedtheGreenGenCompanywithsevenother

ofthelargestenergycompaniesinChina.GreenGensgoalistodevelopanddemonstratean


17/30

14

IGCC+CCSprojectinChinaasoneofthekeytechnologyoptionsforChinaselectricityindustrytouse

totackleclimatechange. Nowtherearemorethan10IGCCpowerplantsproposedinChina,

includingTianjinIGCCdemonstrationpowerplant,whichisownedbytheGreenGenCompanyand

receivedapprovalfromNDRCinMay,2009.AsChinasfirstIGCCplant,itwillstartoperationin2011

andwillbethebasisforafutureIGCC+CCSdemonstrationprojectinChina.

InWorkPackage3twoprecombustionCO2capturecaseshavebeenstudiedindetail,anIGCCwith

CCSsystemusingadryfeedChinesegasifierdesignandachemicalelectricitypolygenerationplant

withCCSusingaslurryfeedChinesegasifierdesign. ParallelfeasibilitystudiesconfirmedthatShell

gasifiertechnologycouldalsobeappliedsatisfactorilytothecoalsbeingused.

Table

2

1

Pre

combustion

Capture

Case

Studies

Case GS1 GS2

Configurations 2400MW

IGCC+CCS

400MW

IGCC+0.3Mt/yr

methanol

Gasification 2TPRI 3Multinozzle

Gasturbine 29FA 19FA

ASU Lowpressure Lowpressure

Chemical

product

Methanol

Shift Twostage OptimisedforMeOH

CO2Separation Selexol Rectisol

CO2Removal

efficiency

90%(overallfor

powerplant)

86.4%(ofCO2at

separationpoint)

4.2 GS1 2400 MW IGCC using TPRI gasifier with CCS (GG)

TheflowdiagramoftheIGCC+CCSplantisshowninFigure41.TheIGCC+CCSsystemconsistsofa

coaldryingandmillingsubsystem,gasificationsubsystem,cleanupsubsystem,watergasshift(WGS),

CO2capturesystem,airseparationunit(ASU), gasturbine(GT), heatrecoverysteamgenerator

(HRSG)andsteamturbine(ST).


18/30

15

ThedrycoalpowderistransportedintothegasifierbynitrogenfromtheASU. OxygenfromtheASU

andsteamfromtheHRSGwillalsobeinjectedintothegasifierwheretheywillreactwiththecoal

powder. Slagproducedinthegasifierfallsdownintotheslagremovalsystemandcanbeusedas

constructionmaterial.Rawsyngasisquenchedwithdustfreecoldsyngasandentersthesyngas

cooler(SGC). IntheSGC,thesyngasiscooleddownthroughtwoheatexchangerswhichcan

producesaturatedsteamattwopressurelevels(highpressureandmediumpressure).Thesaturated

steamgeneratedintheSGCwillbesenttothesteamcyclesystemofthepowerisland.Thecooled

syngasisthendedustedinthedrysolidremovalsystem(DSR)andsplitintotwosubstreams.One

partisrecycledforthesyngasquench,theotherissenttothewetscrubbingsystemwhichremoves

hydrochloricandhydrofluoricacids.ThereactiontoconvertCOtoCO2happensinthewatergas

shift(WGS)unit.TheoutletstreamcomponentsoftheWGSreactoraremainlyCO2andH2.Thenthe

gasentersthesulphurremovalunitandCO2captureunit.SeparatedCO2iscompressedanddried.

TheremainingH2richgas,dilutedwithN2fromtheASU,entersthegasturbineswithcompressedair

fromtheGTcompressortogenerateelectricpower.

TheO2fromtheindependentASUisfedtothegasifier.SomeN2fromtheASUisusedforcoal

feeding,butthebulkoftheN2isinjectedintotheGTcombustortocontrolNOxemissions.Hotflue

gasfromthegasturbinepassesthroughtheheatrecoverysteamgenerator(HRSG).TheHRSGhas

sectionstoraisesteamatthreepressures(HP/IP/LP)andforreheating.Producedsteamissentto

thesteamturbine.Boththesteamturbineandthegasturbinegenerateelectricpower.


19/30

16

TPRI GASIFIER

ASU

Wet

Scrubber

SulfurRecovery

(claus-scottunit)

Gas

Turbine

SYNGAS

COOLER

WGS

HT LT

Acid Gas

Removal

CO2

RemovalHRSG

Dry Solid

RemovalCoal

O2

N2

QUENCHGAS

Air

N2 N2

Steam cycle(steam tubien)

Steam Steam

Steam

Water

Sulfur

O2

H2S

Drying and

compression

CO2

CO2

Poweroutput

Stack

Flue gas

WN

Air

Figure41 DiagramofCaseGS1IGCC+CCSSystem

The2400MWIGCCplusCCSplanthasagrossoutputof866.6MW,lowerthantheIGCCbasecase

withoutCO2capture(946.2MW)becausealargequantityofthesteamisusedintheshiftreaction

insteadofgeneratingelectricityinthesteamturbine.Aftersubtractingpowerusewithintheplantto

runtheASU,CO2compressorandotherequipment661.7MWisavailabletosupply,withanet

efficiencyof36.8%. TheTotalInstalledCostfortheIGCC+CCSplantis8589RMB/kW.

4.3 GS2 1400 MW polygeneration system with CCS (THCEC)

Thepolygenerationsystemisaseriessystem,i.e.chemicalandpoweraregeneratedsequentially.

TheflowsheetforcaseGS2isshowninFigure42.Firstwaterandcoalwillbemixedtoproducea

coalwaterslurry.Thecoalwaterslurryisthenpumpedintothegasifier,whereitreactswithoxygen

fromtheASUandinjectedsteam.Theamountofoxygeninjectedintothegasifierwillbecontrolled

carefully,inordertoavoidgeneratingmoltenslaginthefirststageofthegasifierandtoform

moltenslaginthesecondstage.Slagproducedinthegasifierfallsintotheslagremovalsystemand

canbeusedasagoodqualityconstructionmaterial.Rawsyngasproducedinthegasifieris

quenchedwithsteam.Thequenchedsyngasisthendedustedandcleaneduptoremove

hydrochloricandhydrofluoricacidsinthescrubber.Onepartofthecleanedsyngasissenttothe

watergasshift,wherealmostallCOinthesyngaswillreactwithsteamandchangeintoCO2,then

mixedwiththeotherpartofsyngas.Theratioofshiftedsyngaswillbeusedtocontroltheratio


20/30

17

betweenCOandH2inthemixedsyngastothedesiredvalueformethanolproduction.Before

enteringtheRectisolunit(whichusesmethanolproducedintheplant),thesyngaswillbecooled

downtoabout40Cbyexchangingheatwithwater,becausetheRectisolunitworksatlow

temperatures.IntheRectisolunit,H2SandCO2willbeselectivelyabsorbedbythemethanolsolvent,

andsubsequentlyreleasedbyheatingthesolvent.H2Swillbesenttoasulphurrecoveryunitto

produceelementalsulphur,andCO2willbecompressedfortransportandsequestration(110bar

assumed).ThesyngasleavingtheRectisolunitentersthemethanolreactorcontainingasynthesis

catalyst.Thetailgasisburntwithairinagasturbinetogeneratepower.Thehotfluegasleavingthe

gasturbinethenpassesthroughtheHeatRecoverySteamGenerator(HRSG).TheHRSGiscomposed

ofseveralheatexchangerswhichcanproducesteaminatwopressurereheatsteamcycle(HP/LP).

Thesteamissenttothesteamturbine.Electricityproducedbythesteamturbineandgasturbine

willbesenttothegridnetworkandsuppliedtoelectricityconsumers.Thelowtemperaturefluegas

isreleasedthroughthestack.

TheGS2polygenerationcasehasagrossoutputof525.8MWe+0.32Mt/yearmethanol,andthenet

outputis397.2MWe+0.3Mt/yearmethanol.Theconsumedelectricityisusedforrunningtheplant

facilities,suchastheASU,CO2compressor,pump,fan,etc. andsomeofthemethanolisconsumed

astheRectisolCO2absorptionsolvent.Theoutputofsulphur,abyproductofpolygeneration,is

about13855t/year.TheCO2emissionofthispolygenerationconfigurationis196kg/MWhof

electricity,assumingthatnoneoftheCO2emissionsareassignedtothemethanolproduction. A

consistenttreatmentofthebenefitsofproducingthiscoalderivedmethanolalsowithlower

productionCO2emissionswouldrequireawiderunderstandingofhowthemethanolwasused,

however,andisbeyondthescopeofthisstudy.


21/30

18

Figure42 BlockflowdiagramofGS2polygenerationplant

5. SummaryofCO2captureperformancefordifferentplanttypes

Figure51summarisesthecalculatedtechnicalandeconomicperformanceofarangeofcoalfired

powerplanttypeswithCO2captureunderChineseconditions. Acoalcostof16RMB/GJanda

discountrateof10%overaplantlifeof25yearsareassumed. Theloadfactoristakenas85%

(67.5%infirst,commissioning,year). Costsdonotincludefinancingcostsandtaxes. Othercase

studyparametersaretabulatedinAppendixAandnumericalvaluesforthecaptureperformanceare

presentedinAppendixB. ThecostsofCO2transporttothestoragesiteandstorageandmonitoring

arenotincluded,butcalculatedcostsforpipelinetransport,fromWHU,arepresentedinAppendixD.

Advancednewbuildcapturetechnologiesthathavestilltobedemonstrated,oxyfiring,post

combustionwithaqueousammoniaandprecombustioncaptureonIGCC,arepredictedtoachieve

similarefficienciesof35.6,35.7and36.8%respectively. CAPEXvaluesfortheseplantsare

approximately9000to10000RMB/kWnet,withanestimated+/ 30%uncertainty. Levelisedcosts


22/30

19

ofelectricityfortheseoptionsareestimatedtohavearangeofapproximately370410RMB/MWh.

Costsofabatementarecalculatedrelativetothestandardalternativeplantthatwouldbebuilt,an

advancedsupercriticalplant. Sincethecostofabatementisbasedonthedifferencesbetween

relativelylargernumbersthereismorevarianceintheresults,fromanestimated140RMB/tCO2for

oxyfiringto200RMB/tCO2forIGCC+CCS. Thesevaluesare,however,verysensitivetoestimatesfor

captureplantcosts,particularlytheadditionalcapitalcosts,andshouldberegardedaspreliminary.

Aqueousammoniapostcombustioncaptureispredictedalsotoworkwellretrofittedtoexisting

plant. Absoluteefficienciesarelower,duetoacombinationofthelowerefficiencyofthebaseplant

andhigherpenaltiesduetolesseffectiveintegration,butcalculatedcostsofabatement,ataround

200RMB/tCO2,wouldstillbecompetitivewithothercaptureoptionsstudied.

PostcombustioncapturewithanMEAbasedsolvent,alongestablishedtechnologywhichhasbeen

demonstratedatreasonablescaleforindustrialCO2separationapplicationsalthoughnotyetforfull

scalecaptureonpowerplants,ispredictedtohaveagenerallylessfavourableperformance,with

slightlyloweroverallcaptureplantefficiencyandhighercapital,electricityandabatementcosts.

Thisisinlinewithgeneralexperienceandexplainswhythedevelopmentofalternativepost

combustioncapturesolvents,suchasaqueousammoniabutalsoincludingadvancedaminesanda

rangeofothersystems,iscurrentlyreceivingwidespreadattention.

Polygenerationofelectricityandmethanolappearstohavealowefficiencyandhighcapitalcosts

butthisisbecausethemethanolproductionisnottakenintoaccount. Similarly,thecalculatedcost

ofabatementishighforthispolygenerationoptionbutthisdoesnottakeintoaccountthe

advantagesofproducingcoalderivedmethanolalsowithlowerproductionCO2emissions. A

consistenttreatmentofthesebenefitswouldrequireawiderunderstandingofhowthemethanol

wasused,however,andisbeyondthescopeofthisstudy.

Thesensitivityoflevelisedelectricitycoststovariationsfromthebasecaseparametersisshownin

Fig.5.2. Predictedelectricitycostsdecreasebyabout15%iftheassumeddiscountrateisreduced

from10%to5%,andincreasebyslightlymoreifitisincreasedfrom10%to15%,exceptfor

polygenerationwhichchangesbyabout25%becauseofitshighercapitalcosts. Adecreaseor

increaseof30%inassumedCAPEXgivesacorrespondingchangeinelectricitycostofapproximately

12%,exceptforpolygenerationat17%. Adoublingofcoalprice,fromanassumed16RMB/GJto32

RMB/GJincreasespowerplantgenerationcostsbyaround50%withoutcaptureandby40%with


23/30

20

050

100150200250300350400

Advanced

supercrit

800MW

Oxyfiring Postcom

MEA

Postcom

aqueous

ammonia

Precom

IGCC

Precom

polygen

Existing

600MW

supercrit

Postcom

MEA

Postcom

aqueous

ammonia

Existing

300MW

subcrit

Postcom

MEA

Postcom

aqueous

ammonia

0

200

400

600

800

1000

Advanced

supercrit

800MW

Oxyfiring Postcom

MEA

Postcom

aqueous

ammonia

Precom

IGCC

Precom

polygen

Existing

600MW

supercrit

Postcom

MEA

Postcom

aqueous

ammonia

Existing

300MW

subcrit

Postcom

MEA

Postcom

aqueous

ammonia

0

5000

10000

15000

20000

Advanced

supercrit

800MW

Oxyfiring Postcom

MEA

Postcom

aqueous

ammonia

Precom

IGCC

Precom

polygen

Existing

600MW

supercrit

Postcom

MEA

Postcom

aqueous

ammonia

Existing

300MW

subcrit

Postcom

MEA

Postcom

aqueous

ammonia

0

10

20

30

40

50

Advanced

supercrit

800MW

Oxyfiring Postcom

MEA

Postcom

aqueous

ammonia

Precom

IGCC

Precom

polygen

Existing

600MW

supercrit

Postcom

MEA

Postcom

aqueous

ammonia

Existing

300MW

subcrit

Postcom

MEA

Postcom

aqueous

ammonia

NetEfficiency

(%LHV)

CostofElectricity

(RMB/MWh)

Power plant net efficiencies with and without CO2 capture

Cost of electricity with and without CO2 capture, 85% load factor, 10% discount rate, tax not includedCoal costs: 16 RMB/GJ / 32 RMB/GJ

Capital expenditure

CAPEX = Total Installed Cost + 10% contingency + 7% owners costs, financing costs and taxes not included

Relativetonewbuildadvancedsupercritical pulverisedcoalplant

Relativetoexisting600MW

supercriticalcoalplant

Relativetoexisting300MW

subcriticalcoalplant

CAPEX(RMB/kW)

CostofAbatemen

t

(RMB/tCO2)

Cost of abatement

capture,whilepolygenerationelectricitycostsincreaseby60%. Anincreaseintheassumedselling

priceofmethanolfrom2000RMB/tonneto2500RMB/tonnewouldreducepolygeneration

electricitycostswithcapturebyapproximately10%andbringtheminlinewiththoseforother

captureoptionsforthebasecasevalues(at16RMB/GJcoalcosts).

Figure51SummaryoftechnicalandeconomicperformanceofcoalfiredpowerplantswithCO2

captureunderChineseconditions


24/30

0

100

200

300

400

500

600

700

800

900

Advanced

supercrit

800MW

Oxyfiring Postcom

MEA

Postcom

aqueous

ammonia

Precom

IGCC

Precom

polygen

Existing

600MW

supercrit

Postcom

MEA

Postcom

aqueous

ammonia

E

3

s

Basevalues 5%discountrate 15%discountrate 30%C AP EX +30%CAPEX Coal32RMB/GJ

Levelisedcostof

electricity(RMB/MWh)

Base values: 10% discount rate, Coal 16 RMB/GJ coal, 85% load factor, Financing costs and taxes not

included, CAPEX = Total Installed Cost + 10% contingency + 7% owners costs, Methanol 2000RMB/t

Figure52 Sensitivityoflevelisedelectricitycoststovariationsfrombasecasepara


25/30

22

AppendixACasestudybasis

ThecasestudieswerecarriedoutusingNZECstandardassessmentcriteria,whichwereconsultedon

byWP3groups.Themaincriteriaare:

Plantlocation:Tianjin,PRChina

Shenhuabituminouscoalasdesigncoal,Datongcoalascheckcoal

Coalprice16RMB/GJ,LHV(lowheatvalue)basis

63.75%loadfactorforthefirstoperatingyear,and85%loadfactorforotheroperatingyears

10%nominaldiscountrate(withoutconsideringinflation)

25operatingyears

Notconsideringotherthanlocaltaxes.

90%CO2captureandcompressionto110bar

Theambientconditions,sitecharacteristicsandcoaldataarepresentedinthefollowingtables.

TableA1 SiteCharacteristics

Location Tianjin,PRChina

Topography Level

Coaldelivery Unittrain

Ash/SlagDisposal Offsite

WaterSupply Riverwater

Access Trainandroad

TableA2 SiteAmbientConditions

Elevation(m) 5

BarometricPressure(bar) 1.013

Averageambienttemperature() 15

Maximumambienttemperature() 35

Minimumambienttemperature() 0

AmbientRelativelyHumidity(%) 60


26/30

23

TableA3 CharacteristicsofDesignCoals

Coalspecification UnitDesigncoal

(Shenhuacoal)

Checkcoal

(Datongcoal)

LHV MJ/kg,ar 22.76 26.71

HHV MJ/kg,ar 23.92

Ashcontent

Moisturecontent

Aar(%)

Mar

11

14

9.98

8.84

Ultimateanalysis

Cdaf

Hdaf

Odaf

Ndaf

Sdaf

80.44

4.83

13.25

0.93

0.55

84.43

4.89

8.44

0.91

1.33

Ashcharacteristics

DTC

STC

FTC

1130

1160

1210


27/30


28/30

25

AppendixC CO2captureusingmembranegasabsorptiontechnology(ZJU)

Unlikeconventionalchemicalabsorptiontechnology,themembranegasabsorptiontechnology

studiedbyZJUforNZECusesaminesolvents(MEAinthiscase)insidehydrophobichollowfibre

membranecontactorstoabsorbCO2 i.e.itisbasedonacombinationofmembranegasseparation

andchemicalabsorptiontechnology.Thebasicprincipleofmembranegasabsorptiontechnologyis

shownschematicallyinFig.C1.Unlikegasmembraneseparationprocesses(i.e.,withoutusing

solvents)whichdependsonthemembraneselectivity,thehollowfibresadoptedinthemembrane

contactor,whichhavemanymicroporesintheirwalls(asshowninFig.C2Fig.C2)aregenerallynot

selective.TheselectivitytoCO2isimplementedbythealkalinesolutioninsidethetubes,which

meansthatthedrivingforceforCO2absorptionisbasedontheCO2concentrationgradientbetween

thelumensideandshellsideofmembrane.

Fig.C1.Principleofmembranegasabsorption. Fig.C2.Microporesinthemembranewall.

AtypicalmembranecontactorisshowninFig.C3. Inthehollowfibremembranecontactor,

hydrophobicmicroporousmembranesareusedtoformapermeablebarrierbetweentheliquid

phaseandgasphase,whichpermitsmasstransferbetweenthetwophaseswithoutdispersingone

phaseintoanother.Ingeneral,thegasandliquidphasesalwaysflowinparallel(either

countercurrentlyorconcurrently)toeachotherontheoppositesideofthefibres,andthegas

preferentiallyfillsthehydrophobicmembraneporesandmeetstheliquidattheoppositesideof

membrane. Inthisstudy,polypropylene(PP)membranecontactorswereselectedtoactasthe

absorberinthemembranegasabsorptiontechnologybecauseoftheirlowerpriceandcommercial

availability.Theinnerdiameter(I.D.)ofthePPfibreisabout30 m,theouterdiameter(O.D.)of

fibreisabout40 mandtheporosityofthefibreisabout50%.

InordertopreventmembranewettingproblemsitispreferabletodecreasetheMEAconcentration.

ButlowerMEAconcentrationswillleadtoanincreaseintheflowrateofthesolventand


29/30

26

consequentlyanincreaseinregenerationenergyconsumption.So20%w/wMEAsolutionwas

selectedinthiscase,asacompromisebetweenrelativelyhighersurfacetensionandrelativelylower

solventflowrate. Thecalculatedthermalenergyconsumptionforsolventregenerationunderthese

conditionswas3.98GJ/tCO2. Thiswassignificantlyhigherthanforthe30%w/wMEAsolutionused

inaconventionalabsorber,whichwasestimatedtorequire3.54GJ/tCO2(DCE),andestimated

captureplantcapitalcostswerenotsignificantlydifferent. Soamembranegasabsorptionoption

wasnotincludedindetailedtechnoeconomiccomparisons.

Iffurtherdevelopmentworkwasabletoleadtoincreasedsolventloadingand/orsignificantly

reducedcapitalcoststhentheoperationaladvantagesofmembranecontactorscouldmakethemof

interest. Sincethegasandliquidphasesflowontheoppositesides(i.e.,shellandlumensides)of

thehollowfibrestheycanbecontrolledindependently.Thisisespeciallyeffectiveinavoiding

problemssuchasflooding,foaming,channellingandentrainment,whichcanbeencounteredin

packedortraytowers.

Fig.33 Typicalstructureofhollowfibermembranecontactor


30/30

27

AppendixD LevelisedcostoftransportingCO2asafunctionofmassflowrate

ThefollowingcostsfordensephasesupercriticalCO2transportbypipelineinChinaaretakenfrom

thereportfromWuhanUniversity(WHU). Theyarebasedoncontinuousutilisationofthepipeline

(i.e.365days/year). Forlowerutilisationratesthecostscanbeadjustedreasonablyaccuratelybydividingbytheutilisationfactor.

Cost(CNY/tCO2)vsTransportDistanceL (km)CO2Mass

Flowrate

(tonnes/day) L=50 L=100 L=200 L=300 L=500

2000 16.1535.34 77.35 128.14 225.02

4000 10.2922.52 49.29 81.19 143.42

6000 7.91 17.30 37.87 62.28 110.40

8000 6.5614.35 31.41 51.63 91.78

10000 5.6712.42 27.17 44.67 79.58

12000 5.0411.03 24.14 39.70 70.85

14000 4.569.98 21.83 35.93 64.25

16000 4.189.15 20.02 32.97 59.04

18000 3.87 8.47 18.54 30.57 54.82

20000 3.627.91 17.32 28.57 51.30

co2 emission comparison wp3 final english

Documents