energy.gov/sunshotenergy.gov/sunshotCSPProgramSummit2016

energy.gov/sunshotenergy.gov/sunshotenergy.gov/sunshot

CSPProgramSummit2016

High-Opera+ng-TemperatureHeat-TransferFluidsforSolarThermalPowerGenera+on(LiquidMetals)

AlanBolind,Ph.D.AssistantProjectScienFstUniversityofCalifornia,Berkeley

PrincipalInvesFgators:MarkAsta(UCBerkeley) Y.SungtaekJu(UCLA)PeterHosemann(UCBerkeley) JanSchroers(Yale)

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Outline

§  Overview§  ProblemStatement§  ValueProposiFon§  ObjecFves§  Milestones§  Results§  PathtoMarket

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Overview

•  ProjectName:

•  FundingOpportunity:

•  PrincipleInvesFgators:

•  OtherContributors:

•  ProjectDuraFon:•  ProjectBudget:

HighOperaFngTemperatureHeatTransferFluidsforSolarThermalPowerGeneraFonMURI:HighOperaFngTemperatureFluids(DE-FOA-0000567)MarkAsta,UCBerkeleyPeterHosemann,UCBerkeleyY.SungtaekJu,UCLAJanSchroers,YaleAlanBolind,UCBerkeleyGopinathWarrier,UCLA5years(10/2012–12/2017)$1,104,727includingcostshare,forPhase3

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ProblemStatement

Theproblem,then,is…•  todevelopaliquid-metalheat-transferfluidforCSPthatcanoperateabove650°C,

whilesFllsaFsfyingtradiFonalCSPrequirements,namely,

•  chemicalstability,•  lowmelFngtemperature,•  exisFngorpotenFalcommercialavailability,•  andreasonablyslowcorrosionofpipes.

6¢/kWhEfficiency≥50%

(heattoelectricity)

OperaFngTemperature≥650°C

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ProblemStatement

Defactomainproblem: CORROSIONofpipematerialsbyliquid-metalalloys

Thecorrosiontakestwoforms:

1.  Dissolu+onofthepipe-materialconsFtuentelements2.  Excessiveoxida+onofthepipematerial

Fight#1(dissoluFon)withslight#2(oxidaFon).

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ValueProposi+on

Inwords…A liquid-metal heat-transfer fluid that solves the statedproblem will enable CSP companies to operate their CSPplantsathighertemperaturesandtherebyachievegreaterefficienciesandconcomitantlowercosts.Unlikehigh-temperaturegasesthatneedhighpressuresforsufficientdensity,andunlikemoltensaltsthateitherfailtomelt at low temperatures or decompose at hightemperatures, liquid metals stay liquid, without excessivepressure, over the temperature range of interest for CSPoperaFons.

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ValueProposi+on

Inpictures… 800°C!!η>50%!!

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Objec+ves

Mark Asta

Modeling

ThermodynamiccalculaFonsof…•  ProperFesofLM•  ProtecFvescalesonPM

•  OxygendissolvedinLM

Jan Schroers

Sungtaek Ju

Peter Hosemann

Fast-screeningexperiments•  LMthermophysicalproperFes•  LM/PMcorrosionreacFons

LM:LiquidMetalPM:PipeMaterial

Sta+c,autoclaveexperiments

•  CorrosiontesFngofPMstripsincruciblesofLM

•  DevelopmentofcontrolofoxygendissolvedinLM

Flowing,loopexperiments•  CorrosiontesFnginflowingLM•  OperaFonaldataforaLMloop

ObjecFvesofeachteammember

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Milestones

•  IdenFfied>50LMalloyswithTmelFng<300°C.•  EstablishedopFmaloxygenconcentraFonrange;quanFfiedoxide

growthanddissoluFonratesasfuncFonsoftemperatureandoxygenconcentraFon;andidenFfied1PMalloywithcorrosion<150µm/yr

•  CalculatedfreeenergiesofformaFonofprotecFveoxideandintermetallicscalesforLMalloysofLBE+athirdaddiFve.

•  QuanFfiedLM/PMreacFonwithaddiFves(e.g.,Zn,Sb,Ge),bybothfastscreeningandstaFccorrosiontests.

•  IdenFfiedthebestPb-BialloycomposiFonforLM/PMreacFon.•  ConductedtensiletesFngtoshowabsenceofliquid-metal

embriwlement.•  Verifiedtheleak-Fghtnessoftheflowloopatroomtemperature.

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Results

=rejectedayeriniFalscreenings

=rejectedayerstaFccorrosiontesFng

=testedandmostacceptable

=sFlltobetested,asanaddiFve

SelecFonofLMcomponents

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Results

•  Lead-BismuthEutecFc(LBE)is45%Pb,55%Bi,bymass.•  ThisLBEisourdefaultliquidmetalofchoice,because…

•  itisnottooexpensive(Pbisverycheap),•  itisnotexcessivelychemicallyreacFveortoxic,•  PbandBiaretheleastcorrosiveoftheelements,•  andtheeutecFccomposiFonhasthelowestmelFngtemperature(125°C).

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Results

•  ExamplesofcalculaFons

6"8"10"12"14"16"18"20"22"24"26"

0"

50"

100"

150"

200"

250"

300"

1.3" 1.4" 1.5" 1.6" 1.7" 1.8" 1.9" 2.0"

Density

(at(Liquidu

s(Tem

p.((g/cm

3 )(

Liqu

idus(Tem

perature((°C)(

Volumetric(Heat(Capacity((J/(cm3(K))(

Liquidus"T."Density"

PbO(s)->Pb(LBE)+O(LBE)

Al(Kanthal)+O(LBE)->Al2O3(s)

GeO2(s) -> Ge(LBE) + 2 O(LBE)

LMproperFes

Windowforproperoxygencontrol

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Results

Ding,S.,Y.Liu,Y.Li,Z.Liu,S.Sohn,F.Walker,andJ.Schroers,NatureMaterials,13,494,(2014).

Yale’ssetupforfastscreening:dropsofLMonaPMdisk

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Results

•  Exampleoffast-screeningofLM/PMcorrosionreacFons

Figure 2.1.2‑3: The effect of Sn content on the penetration depth (denoted by the dotted yellow lines) �of LM into Kanthal steel PM. �

(1) Bi55.4Sn38.3Zn6.3 (2) Bi43.3Sn51.6Zn5.1 (3) Bi25.1Sn72Sb2.9 (4) Sb9.9Zn1.6Sn88.5

38.3% Sn 51.6% Sn

72.0% Sn 88.5% Sn

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Results

•  Longer-termstaFccorrosiontests•  DissoluFonprotecFonisbyaluminum-oxidescales(Al2O3).

•  Therefore,weuseKanthalsteelsbecausetheyhave6%Al,bymass.

ALK-type Kanthal Steel

LBE (Pb-Bi Eutectic)

Fe Cr

Al O

Pb Bi

GoodExample

1000hours

700°C

10-6wt.%dissolvedoxygen

20µm

Steelstrips

CrucibleofLM

Holder

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Results

LBE

APMT-typeKanthalsteel

DetachedAloxidescale Adherent

Aloxidescale

BadExample

1000hours

800°C

10-6wt.%dissolvedoxygen

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Results

Oxide growth on Fe-Cr-Alferri+c steels (Kanthal)during exposure to sta+cLBEat700°Cwith1·10-6wt.%Oforupto660h

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Results

•  Aforced-convecFonliquid-metalflowloophasbeendesigned,constructed,andleaktestedwithgasatroomtemperature.

•  WorkisconFnuingtoiniFateflowexperimentsusingaliquidmetal(LBE).

Radiant heater

EM flow meter

Plenum (O2 sensor, hot-leg) Supply tank

Melt/drain tank

EM pump

HX (cooling section)

Sampling station

Magnetic trap

2.2 m

1.2 m

0.6 m

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PathtoMarket

•  Thisresearchproject

•  IndustrialcollaboraFon

•  Industry

èExperimentalevidenceofLBEasahigh-temperatureheat-transferfluid

èBuildascaledtestloopwithCSP-likeconfiguraFon,andtestoveramoreexhausFverangeofoperaFngparameters

è BuildaprototypeCSPplantwithliquidmetalastheheat-transferfluid

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Outline

§  Overview§  ProblemStatement§  ValueProposiFon§  ObjecFves§  Milestones§  Results§  PathtoMarket