al air battery

8/3/2019 Al Air Battery

1/22

JFC:Jun-03

DIRECT CARBON (COAL) CONVERSIONBATTERIES AND FUEL CELLS

Presented to

Fourth Annual SECA MeetingApril 15-16, 2003 Seattle WA

by

John F. Cooper and Roger Krueger Chemistry and Materials Science DirectorateLawrence Livermore National Laboratory Livermore CA 94550

Tel. 925-423-6649 Fax 925-422-0049 email [email protected]

This work was performed under the auspices of the U.S. Department of Energy by University of California,Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.
mailto:[email protected]:[email protected]


2/22

JFC:Jun-03

Topics

Concept Thermodynamic and Chemical Basis Technical Approach and Results The Synthesis of Carbon Electrochemical Fuels Conclusions


3/22

JFC:Jun-03

Direct Carbon Conversion Fuel Cell and Battery:Electricity From C/O2 Electrochemical Reaction

Electric energy

CO2

Air in

Air out

Cathode : O2 +2CO 2 + 4e - = 2CO 32-

Anode : C + 2CO 32- = 3CO 2 +4e

Net reaction: C+O 2 = CO 2

_ +

Carbon

T = 675 C

High fuel cell efficiency: 80% of H 298 (HHV),

H 298 = 32.8 MJ/kg-C [9.1 kWh/kg-C], S ~ 0, fixed C and CO 2 activities

High specific energy battery: 3-4 kWh/kg (~3.5 kWh/liter) at 100-133 W/kg

Fixed C, CO 2 activities make possible invariant EMF and full fuel utilization Boudouard corrosion is expected only at low polarization: C + CO 2 = 2CO

High fuel cell efficiency: 80% of H 298 (HHV),

H 298 = 32.8 MJ/kg-C [9.1 kWh/kg-C], S ~ 0, fixed C and CO 2 activities

High specific energy battery: 3-4 kWh/kg (~3.5 kWh/liter) at 100-133 W/kg

Fixed C, CO 2 activities make possible invariant EMF and full fuel utilization Boudouard corrosion is expected only at low polarization: C + CO 2 = 2CO


4/22

JFC:Jun-03

Routes to Power Production at Efficiencies > 70%

Electrochemical conversion

Air Electric power

Sequester or reuseCO2

CC & H

2 Pyrolysis Petro-coke Natural gas Petroleum Coal, lignite

H2

Fuel cells[or turbines, refinery, etc .]

70 80 % efficiency, HHV

The pyrolysis of CH x => C + (x/2)H 2 consumes 3-8% of fuel value; no ash H2 co-product has multiple uses: fuel cells, chemical value, combustion

The pyrolysis of CH x => C + (x/2)H 2 consumes 3-8% of fuel value; no ash H2 co-product has multiple uses: fuel cells, chemical value, combustion


5/22

JFC:Jun-03

The Carbon Air Technology Evolved fromLLNL Internal Research

FY2002-3

IL-11101

Allows stacking and refueling of smallassemblies; discovery of low-Tmaterials; DOE NA22, ARL, ARO

Rigidanode

LDRD FY01-02IL-10848

Developed cell enabling scale up,refueling, controlled wetting of carbon

Angledcell

LDRD, FY00-02Structure, conductivity effects studied;Carbon anode mechanism proposed;Data base of diverse fuels from slurrycells in full-cell configuration

AnodeR&D:rates andstructure

CEES 1999LDRD, IL-10479

Particles + melt mimic rigid electrodeExperimental slurries in full cells

Particleanodes

CEES 1999Defined approach relating structure to

rate; first full-cell experiments ever

Nano-

structures

Sponsor/Year Contribution Area

+ AuRef

Gas analysis

Carbon paste

Moltensalt

Current collector

Porousalumina

O2/CO2 controlled atmosphere

+ AuRef

Gas analysis

Carbon paste

Moltensalt

Current collector

Porousalumina

O2/CO2 controlled atmosphere

Alumina tube

Separator

Anodecollector

Anode lead

Cathode lead

Cathodecollector

Carbon fill

Air fill

Alumina tube

Separator

Anodecollector

Anode lead

Cathode lead

Cathodecollector

Carbon fill

Air fill

Alumina tube

Separator

Anodecollector

Anode lead

Cathode lead

Cathodecollector

Carbon fill

Air fill

AA10 cm

AA10 cm

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0.0

C e

l l P o

t e n

t i a

l ( V )

16012080400

Current (mA/cm2)

60

50

40

30

20

10

0

P ow

er

( mW

/ c m2

) Ac Blk- small cell 800 CPetCoke- small cell 800 CAc Blk- lg cell 850 CPetCoke- lg cell 850 C


6/22

JFC:Jun-03

Comparison of Fuels for Fuel Cells

0.450.800.800.70H2

0.570.800.800.895CH4

0.800.801.01.003C

Total efficiency =(G/ H ostd )()( v)

V(i)/V(i=0)= v

Utilizationefficiency,

Theoretical limit =G(T)/ H ostd

Fuel

0.450.800.800.70H2

0.570.800.800.895CH4

0.800.801.01.003C

Actual efficiency =(G/ H ostd )()( v)

V(i)/V(i=0)= v

Utilizationefficiency,

Theoretical limit =G(T)/ H ostd

Fuel

a

o

Efficiency of a fuel cell(electrical energy out) / (HHV thermal value of fuels in)

[G(T)/ H][ ][V/V]= [theoretical eff][utilization][voltage efficiency]--where G(T) - nFV H-TS

Efficiency of a fuel cell(electrical energy out ) / (HHV thermal value of fuels in )

[G(T) /H][][V/V]= [theoretical eff][utilization][voltage efficiency]--where G(T) - nFV H-TS

Fundamental advantages derivefrom thermodynamics of the C/O 2 reaction and fixed

activities of the reactants


7/22

JFC:Jun-03

Past efforts limited by ash entrainment,electrode fabrication and logistics

Technical background

History Jacques [1898]: 15 kW coal batteries

C + 2KOH + O 2 = K2CO 3 + H2O ~10 2 papers in 20 th century

Efficiency not driver, CO 2 not pollution Weaver [1980]: found reactive cokes >98% utilization at 750 C Power levels => 0.8 kW/m 2 @ 1 kA/m2

Vutetakis [1985]

Fundamental studies of ground C slurries Suggested nano-scale disorder mightenhance rate

Barriers to electricity direct from coal Ash entrained into melt

Electrode fabrication, distribution costs Resistance of rigid electrode,highpolarization

Relation to Molten Carbonate Fuel Cell Similar cathode, melt

No H 2 or steam corrosion More tolerant of S (no anode catalyst)

Jacques [1898]

Weaver [1981]


8/22

JFC:Jun-03

At Temperatures of 400-1100 C, the Only Reactionis C + O 2 CO2

T = 900-1100 C, NaAlF 4 + Al 2O3,turbo & graphite

T = 700 C, CO 32-

Large volume,free slurry

T = 700-800 C,rigid reactivecarbons and coke

T = 400-900 C,graphite, CO 32-

T = 700 C,graphite,carbonate

Conditions

Thonstad[1970]

n = 4u ~ 1.0

d[CO 2]/dt = I/nFanode CO ~ 0: noBoudouard rxn

Vutetakis

[1984]

n = 4

u poor

d[CO 2]/dt = I/nF

Weaver [1977-9]

n = 4u ~ 1.0

dV/dt; W

Hauser [1964]

n = 4u ~ 1.0

dV/dt; [CO]/[CO 2]

Tamaru &Kamada[1937]

n = 4

u not reported

W, dV/dt ~ I/nF

ReferenceResultsMethod used


9/22

JFC:Jun-03

Studies with 60 cm 2 Angled Cell Anticipate Fuel Cell

60 cm2

angled cell

Alumina tube

Separator

Anodecollector

Anode lead

Cathode lead

Cathodecollector

Carbon fill

Air flow tube

SumpExcess meltreservoir

Alumina tube

Separator

Anodecollector

Anode lead

Cathode lead

Cathodecollector

Carbon fill

Air flow tube

SumpExcess meltreservoir

-

+

-

+

-

+

-

+

Tilted orientation allows control of wetting Fuel cell option for exchange of electrolyte Basis of patent-pending

Cell in heater


10/22

JFC:Jun-03

Voltage Stability, 80% Efficiency and SuccessfulScale-up of Powder-fed Fuel Cell

1.4

1.2

1.0

0.80.6

0.4

0.2

0.0

C e

l l P

o t e n

t i a

l ( V )

16012080400

Current (mA/cm2)

60

50

40

30

20

10

0

P ow er ( mW

/ c m2 )

Ac Blk- smal l cell 800 CPet Coke- sma ll cell 800 CAc Blk- lg cell 850 CPet Coke- lg cell 850 C

-1.2

-1.0

-0.8

-0.6-0.4

-0.2

0.0

C e

l l P o

t e n

t i a

l ( V )

3020100Time hrs

T = 800 C

0.90-0.98 V, constant current, 75 mA (27 mA/cm2)

Voc = 1.13 V

Scale up 2.8 to 60 cm 2Scale up 2.8 to 60 cm2

Alumina tube

Separator

Anodecollector

Anode lead

Cathode lead

Cathode

collector

Carbon fill

Air fill

Alumina tube

Separator

Anodecollector

Anode lead

Cathode lead

Cathode

collector

Carbon fill

Air fill

Alumina tube

Separator

Anodecollector

Anode lead

Cathode lead

Cathode

collector

Carbon fill

Air fill

Stable voltageduring 30 h test at

constant load

Stable voltageduring 30 h test at

constant load


11/22

JFC:Jun-03

Demonstrated >100 mA/cm 2 at 80%Efficiency With Carbon Black Fuels

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

C e

l l P

o t e n

t i a

l ( V )

200150100500Current Density (mA/cm

2)

120

100

80

60

40

20

0

P ow er D

en s i t y

( mW

/ c m2

)

Furnace Black800 C day 1700 C day 3

Green Needle Petroleum Coke800 C

120 mA/cm2

at 0.8 V

Performance sustained until fuel consumed (> 3 days) Performance sustained until fuel consumed (> 3 days)Data: N.Cherepy


12/22

JFC:Jun-03

New Rigid Block Materials: Half-Cell Research

+ VConst I

Luggin probe

Anode

SS cathode

Measures anode polarization against Au/0.28CO 2, 0.14O 2


13/22

JFC:Jun-03

Enhanced Performance with Composite Platesat 650-700 C

0.50

0.60

0.70

0.80

0.90

1.00

1.10

0 100 200 300 400 500 600

Current density, mA/cm2

E a v s

A u

/ C O 2 , a i r

650 C675 C700C725 C750 C

Properties of compositesDensity: >25 % theoreticalConductivity > 25 -1cm -1

With separator, cathode at700 C: 1 kW/m 2 @ 80%

efficiency 4.5 kW/m 2 peak power

Ongoing tests on 50 cm 2

Properties of compositesDensity: >25 % theoretical

Conductivity > 25 -1

cm-1

With separator, cathode at700 C: 1 kW/m 2 @ 80%

efficiency 4.5 kW/m 2 peak power

Ongoing tests on 50 cm 2

Recently studied class of high-density C composite platesyielded twice previously achieved power at 100 C lower T.

Expected 80% efficiency at 50-500 mA/cm2


14/22

JFC:Jun-03

Experimental Approach: Rigid Plate Anode withFlow Field and Improved Diagnostics

Au ref Va prob

+Air/CO 2 flow field

-

CO2Overflow

Vc prob

Au ref

Independent reference electrodes and voltage probes Precise control over gas composition and flow

Isolation of reaction zone in rigid carbon block

DOE/NETL Project,

FY 2003


15/22

JFC:Jun-03

The synthesis of carbonelectrochemical fuels


16/22

JFC:Jun-03

Extraction and Use of Carbon from Coal Solvent-extraction of

ash-free carbons Direct Carbon Conversion

Fuel cell

_ +

CO 2 out

Air in

Air out

CoalCoalresiduals,

Ash, pyrite

Clean coal

> 90 % 80 %> 72 %

_ +

CO 2 outAir out

_ +

Electric

power

CO 2 outAir out

Coalresiduals,

Ash, pyrite, mid BTU gas

Clean coal

> 95 % 80 %> 75 %

Solvent extraction yields coal with 0.01% ash Recycles benign solvents, negligible loss (0.7 %) per cycle Unconverted coal retains thermal value

Solvent extraction yields coal with 0.01% ash Recycles benign solvents, negligible loss (0.7 %) per cycle Unconverted coal retains thermal value

A. Stiller, J. Zondlo, WVU; B. K. Parekh, U. Kentucky


17/22

JFC:Jun-03

Hydraulic Cleaning of Coal

Air

Hydraulic separation of C ( 0.8 /kWh for fuel

But: high ash requires further cleaning or periodic electrolyte exchange

Coal Bake out

Mid BTU Gas,steam

Pulverization andHydraulic Separationfrom Ash & Pyrite

Ref.: B. K. Parekh, U. Kentucky


18/22

JFC:Jun-03

Clean Carbon Fuels from Hydropyrolysis

heat pyrolysisH2-coal

Reactive C

H2 H2 slipstream(6%)

Un-reacted chars,Sulfur, toxic ash

_ +Electric power out

CO 2 out

Air in

Air out


_ +Electric power out

CO 2 out

Air in

Air out


Fuel Cells, turbines, refinery, etc.

CH4Biochar orLignite +lime

Extraction of Carbon from Coal Seam by in situ methanation ?

f l l


19/22

JFC:Jun-03

How Often Must Electrolyte BeReplaced?

Interval between electrolyte replacement/recycle 0.5% ash hydraulic cleaned coal 200 days (twice yearly)

0.05% ashsolvent extracted coal 5.5 years (life of cell) 0.01% ashpyrolyzed oil N/A

For 0.5% ash cleaned coal For common fuels under consideration, cost of

electrolyte exchange is insignificant

Lowest recycle cost if Na/K eutectic is used:$2.5/kW per exchange, assuming 20 /lb salt200 days between exchange => 0.05 /kWh

For 0.5% ash cleaned coal For common fuels under consideration, cost of

electrolyte exchange is insignificant

Lowest recycle cost if Na/K eutectic is used:$2.5/kW per exchange, assuming 20 /lb salt200 days between exchange => 0.05 /kWh

Summary: Efficient Processes for


20/22

JFC:Jun-03

Summary: Efficient Processes for Cleaning Coal

UK: hydraulic separation grind to 30 m; baking to remove mid-BTU gas; low-ash product

UK-process: extraction of pitch with anthracene oil 425 C, 200 atm; no hydrogenation; 40-70% yield; 0.05-0.1 % ash

WVU-process: extraction of pitch with n-methyl pyrrolidone

Ambient pressure, 200 C; 40-50% yield; 0.05-0.1 % ash

$78-140/ton,1-2 -fuel/kWh

$200/ton,2.4 -fuel/kWh

$60/ton, $3/GJ0.8 -fuel/kWh

Cost

0.5-10.0540-50%> 90%WVU-solvent

0.50.0540-70%> 90%UK-solvent

1-20.5-1100%98%UK-hydro%S %AshYield Efficiency Process


21/22

JFC:Jun-03

Initial Hardware Cost Estimates

Stack cost ~ $250/m 2 at 2 kW/m 2

Component or factor Basis Cost $/kWZirconia fabric Zircar, Inc. retail

price $200/m 2 100

Nickel felt Eltech, Inc. $20/m 2 retail price

10

Stainless steel lid Ni plated SS frame,$5/lb

38

Graphite base, collector $1.00/lb design 10Assembly 20% parts 32G&A, profit 20% parts and labor 48Total $237


22/22

JFC:Jun-03

Acknowledgments

LLNL Collaborators J. F. Cooper, Chemistry, Electrochemical Engineering Nerine Cherepy, Chemistry Larry Hrubesh, Physics Ton Tillotson (advanced composite materials) Roger Krueger, Sr. Techn. Associate

Consultants and advisors Prof. Rob Selman IIT (Molten Carbonate Fuel Cell) Dr. Kim Kinoshita (LBL, ret.; Carbon properties)

Meyer Steinberg (BNL) fossil fuel to carbon processing MesoSystems Technology (Kennewick WA). Thermal engineering

LDRD and CEES; DOE NA-22; ARL; ARO; DOE/NETL

al air battery

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