High Density Hydrogen Storage System Demonstration Using ... fileUnited Technologies Research Center Program Specifics Objective: Develop, build, bench demonstrate and deliver an in-situ

United Technologies Research Center

High DensityHydrogen Storage System Demonstration

Using NaAlH4 Complex Compound Hydrides

D.L. AntonD.A. MosherS.M. Opalka

United Technologies Research CenterE. Hartford, CT C. Qiu

G.B. OlsenQuesTek, LLCEvanston, IL

F.E. LynchHCI, Inc.

Littleton, COMerit ReviewBerkeley, CA

May 19-20, 2003Rev. B


Program Specifics

Objective: Develop, build, bench demonstrate and deliveran in-situ rechargeable 5 kg H2 capacity hydrogen storage system suitable for operation of a PEMFC powered mid-size auto application based.

Approach: Design a low pressure hydrogen storage system initially utilizing catalyzed NaAlH4, but capable of being altered to use “any” chemical hydride having the higher gravimetric and/or volumetric hydrogen storage densities.


Program Outline• Heat/Mass Transfer Analysis• 1kg H2 Prototype/Evaluation• 5kg H2 Prototype/Evaluation• 5kg Prototype Delivery

• Safety Analysis• Atomistic/Thermodynamic Modeling• 50g H2 Prototype System• Media Kinetic Modeling

CCH HydrogenStorage System

PEMCell StackAssembly

Hot

Cool

Hydrogen (~1 atm.)

Hydrogen (~50 atm.)

ColdWarm

RechargingSystem

DischargingSystem

HotWater

Manual Control

Hydrogen (~1 atm.)

BOP

CoolWater

Power


Milestone ChartID WBS Task Name1 1 CCH Storage Media Development2 1.1 50g H2 Sub-System Evaluations

6 1.2 50g Media Evalautions

18 1.3 NaAlH4 Thermodynamic Modeling

29 1.4 GO/NO GO Milestone

30 2 CCH Storage Sys. Demonstration31 2.1 Safety Analysis

36 2.2 1Kg System Evaluation

37 2.2.1 Design/Fabricate CCHSS#1

45 2.2.2 CCHSS#1 Evaluation

48 2.3 GO/NO GO Milestone

49 2.4 5Kg System Evaluation

50 2.4.1 Design/Fabricate CCHSS#2

58 2.4.2 CCHSS#2 Evaluation

65 2.4.3 Ship CCHSS#2 to DoE

66 2.5 Reporting

4/30

4/30

9/2

Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q42002 2003 2004 2005 2006


Milestones vs.DoE 2005 & 2010 Goals

Metric Units 2005 DoE Goal 2010 DoE Goal

UTRC 2003

Estimate

UTRC Prop.

GO/NoGoMax. H2

Delivery Temp.oC 100

Min. H2

Delivery Temp.oC -20 -30 TBD

Min. Full Flow g H 2/sec. 3.0 4.0 0.31 0.30FC Min. Pressure

kPa/bar 250/2.5 250/2.5 TBD

ICE Min. Pressure

kPa/bar 1000/10 3500/35

Purity % (dry) 99.9 99.9 TBD0-90% 90-0%

sec. 0.5 0.5 TBD

start to full flow @20oC

sec. 4.0 0.5 TBD

start to full flow @-20oC

sec. 8.0 4.0

Refueling Rate kg H 2/min. 0.5 1.5 0.30 0.30Loss of Useable H2

g/hr kg H 2 1.0 0.1 TBD

Permeation & Leakage

scc/hr TBD

Toxicity TBD

Safety TBD

Federal enclosed-area safety standard

Meets or exceeds applicable standards

Meets or exceeds applicable standards

Tran

sien

t R

espo

nse

Hyd

roge

n D

eliv

ery

Metric Units 2005 DoE Goal 2010 DoE Goal

UTRC 2003

Estimate

UTRC Prop.

GO/NoGo

Capacity kg 5

Gravimetric kWh/kg 1.5 2 0.83 1.00

Volumetric kWh/l 1.2 1.5 0.40 0.55

Total life cycle (15 yr/150k miles)

$(03)/kWh 6.00 4.00 16

Fuel (gasoline equivilent)

$(01) 3.0 1.3 TBD

Marginal Fuel Cost (Ref. $1/kWh for H2)

$(03)/kgH 2 NA 1.5 TBD

Min. oC 0 -30 TBD

Max. oC 50 50 50

Cycle Life (0.25-100%)

N 500 1000 TBD

Mean % N/A 90 TBDConfidence % N/A 90 TBD

H2

Sto

rage

D

ensi

tyC

ost

Ope

ratin

g Te

mpe

ratu

reC

ycle

Life


Development Partners

Hydrogen StorageTask XVII

Advanced Fuel Cell SystemsTask XV


Commercial Materials Characterization

Summary

12.66.414.57.5Alo

x-rayanalytical

1.5Inert*

2.66.02.44.7Na3AlH6

84.887.583.186.3NaAlH4

at%wt%at%wt%

5.2Wt% H2 th

4.9Wt%H2

94.7%% Charge

0.9Na:Al

* Probably glassy NaOH, NaAl(OH)4 …

0.2mm

0.2mm

20 25 30 35 40 45 50

500

1000

1500

55 60 65 70 75 80 85 902-Theta(°)

500

1000

1500

73-0088> NaAlH4 - Sodium Aluminum Hydride04-0787> Aluminum, syn - Al

42-0786> AlH6Na3 - Sodium Aluminum Hydride

Inte

nsity

(CPS

)

theta cal

Bgd & Ka2 Subtd

Al

Al Al

Al

NaAlH4

NaAlH4

NaAlH4NaAlH4

NaAlH4

Na3AlH6

NaAlH4

NaAlH4

NaAlH4

Na3AlH6

Na3AlH6 Na3AlH6

NaAlH4NaAlH4

[DS570.MDI] Albemarle,NaAlH4,AsReceived,blackpowder Psi 0.0


Safety Analysis DOT/UN Doc., Recommendations on the Transport of Dangerous Goods, Manual of Tests and Criteria,

3rd Revised Ed., ISBN 92-1-139068-0, (1999).

•• FlammabilityFlammabilityFlammability TestSpontaneous IgnitionBurn Rate

•• Water ContactWater ContactImmersionSurface ExposureWater DropWater Injection

•• Dust Explosion (ASTM E1226)Dust Explosion (ASTM E1226)Pmax & (dP/Dt)maxMin. Exp. Conc.Min. Ignition EnergyMin. Ignition Temp.Min. Dust Layer Ignition Temp.

CCH#0: 2m%TiCl3Fully Charged, CCH#0-100: (NaAlH4)Partially Discharged, CCH#0-33: (Na3AlH6+2Al)Fully Discharged, CCH#0-0: (NaH+Al)


Flammability Test

25 mm3

Objective: To determine if material spontaneously self heats or ignites upon exposure to air at 100oC

0

50

100

150

200

250

300

350

0 60 120 180 240 300 360 420

TEST PERIOD, SECONDS

TE

MP

ER

AT

UR

E, C

OVEN TEMPERATURE

DANGEROUS SELF-HEATING DEFINITION, 160C

THERMOCOUPLE FAILEDFully Charged(NaAlH4)

0

200

400

600

800

1000

1200

1400

0 100 200 300 400 500 600

TEST PERIOD, SECONDS

TE

MP

ER

AT

UR

E, C

RESIDUAL Na3AlH6DESORPTION

NaH DESORPTION

THERMOCOUP LE BURNT OFF

DANGEROUS S ELF-HEATING DEFINITION, 160 C

OVEN TEMP ERATURE

SPECIMEN TEMPERATURE

Na OXIDATION

0

50

100

150

200

0 60 120 180 240 300 360 420 480 540 600 660 720 780 840 900

TIME, SECONDS

TE

MP

ER

AT

UR

E, C

DANGEROUS SELF-HEATING DEFINITION

134C

Fully Discharged (NaH+2Al)

Partially Discharged(Na3AlH6+2Al)


Safety Testing ResultsClass 4.3, Packing Group II:No change from uncatalysed material.

Test Method Ref: 100% 33% 0%UN33.

Prelim. Screening 2.4.3.1 Yes, Flammable Solid Yes, Flammable Solid Yes, Flammable Solid

Burning Rate 2.4.3.2 51 mm/sec 222 mm/sec 27 mm/sec

Burning Rate, 80C Note 1 127 mm/sec spontanious ignition 40 mm/sec

Spontaneous Ignition, R.T. 3.1.4.3 6 Tries, Not Pyrophoric 6 Tries, Not Pyrophoric 6 Tries, Not Pyrophoric

Spontaneous Ignition, 80C Note 1 6 Tries, No Ignition 1 Try, Ignited 6 Tries, No Ignition

Dangerous Self-Heat, 100C 3.1.3.3 Yes, Dangerous Yes, Dangerous Not Dangerous

Dangerous Self-Heat, 120C 3.1.3.3 Not Tested (Note 2) Not Tested (Note 2) Not Dangerous

Dangerous Self-Heat, 140C 3.1.3.3 Not Tested (Note 2) Not Tested (Note 2) Yes, Dangerous

Dangerous When Wet 4.1.4.3 Yes, Class 4.3, Pack Gp 1 Yes, Class 4.3, Pack Gp 1 Yes, Class 4.3, Pack Gp 1Note 1: This is not a UN standard test. We want to know what happens when this material is spilled at operating temperature of 80C. All other details are per UN burn rate and spontaneous ignition test specifications.Note 2: This test was not necessary, since this material had already shown dangerous self-heating at 100C.

SAFETY TESTING TABLE OF RESULTS


Thermodynamic Modeling

ThermoCalcThermodynamic Simulations of

multi component phase diagrams

VASPAtomistic simulations based on Density Functional Theory with

pseudo-potentials for core electrons

Na0.0 0.1 0.2 0.3 0.4 0.5 0.6

Al

0.0

0.1

0.2

0.3

0.4

0.5

0.6

H

0.4

0.5

0.6

0.7

0.8

0.9

1.0

% Sodium

% Aluminum

% H

ydro

gen

NaH

Na3AlH6

NaAlH 4

AlH3

Tm

Objective: Combine atomistic and thermodynamic modeling to predict: (i) quaternary phase diagrams and (ii) thermal stability of catalyzed compounds.Approach: Atomistic calculations used to predict ∆Hf at 0K. Thermodynamic calculations to determine ∆Gf vs T & P


Calculated Na-Al-Ti-H Phase Diagrams

0

10

20

30

40

50

60

70

80

90

100 T

i, at

.%

0 20 40 60 80 100

Al, at.%

TiAlTiAl33

TiHTiH22

NaHNaHNaAlHNaAlH44+fcc(Al)+TiAl+fcc(Al)+TiAl33

NaAlHNaAlH44+TiH+TiH22+TiAl+TiAl33

←←NaNa33AlHAlH66+NaAlH+NaAlH44+TiH+TiH22

100oC 100atm PH2

NaH Al

0

10

20

30

40

50

60

70

80

90

100

Ti,

at.%

0 20 40 60 80 100

Al, at.%

hcphcp

TiTi33AlAl

TiAlTiAl

TiAlTiAl22

TiAlTiAl33

liq(Na)+fcc(Al)+TiAlliq(Na)+fcc(Al)+TiAl33

liq(Na)+TiAl

liq(Na)+TiAl33+TiAl

+TiAl22liq(Na)+TiAl

liq(Na)+TiAl 22+TiAl+TiAlliq

(Na)+

TiAl+Ti

liq(N

a)+TiAl+Ti 33

AlAl

liq(N

a)+h

cp+T

i

liq(N

a)+h

cp+T

i 33AlAl

100oC

Ti

NaAl 0

10

20

30

40

50

60

70

80

90

100

Ti,

at.%

0 20 40 60 80 100

Al, at.%

TiAlTiAl33

TiHTiH22

NaNa33AlHAlH66+fcc(Al)+TiAl+fcc(Al)+TiAl33NaH+NaNaH+Na33

AlHAlH66+TiAl+TiAl33

NaH+TiHNaH+TiH22+TiAl+TiAl33

→→100oC 1atm PH2

NaHAl

Ti

Ti

NaxAlyHz-TiH2-Al3Ti are stable phases of

interest


Is transition metal “catalytic” effect in NaAlH4 catalysis or thermodynamics?

At 90oC, Na3AlH6 is too stable to access last % H2Pe ~ 0.5 bar

Gross, Sandrock & Thomas

2% Ti+3 doped

Urgent requirement to destabilize Na3AlH6 by

20oC (0.5bar)!!


Quantum Mechanical Calculations NaAlH4: Enthalpy of Formation at 0K

-14

-12

-10

-8

-6

-4

0.0 0.1 0.2 0.3 0.4 0.5

Site-fraction of Li, Ti, V, or Zr

Enth

alpy

, (kJ

/mol

e-at

om)

V

TiZr

Li

NaAlH4 NaMH4 or LiAlH4

Na16TiAl15H64

Supercell6.25 mole % NaTiH4

NaAlHTi

-22

-18

-14

-10

-6

0.0 0.2 0.4 0.6 0.8 1.0

Site-fraction of M (Ti, Zr, V, Li)

Enth

alpy

, (kJ

/mol

e-at

om)

Ti

Zr

V

Li

Na3AlH6 Na3MH6 or Li3AlH6

(Na1-yAmy)(TmxAlx-1)H4 (Na1-yAmy)3(TmxAlx-1)H6

Na6TiAlH12 Supercell50 mole % Na3TiH6


Thermodynamic CalculationsTi+3 Additions

NaHo

AlHo

NaAlHo GGTTcTbaG ++++=

34ln111

NaHo

AlHo

AlHNao GGTTcTbaG 3ln

363 222 ++++=∆οH vs. T & [Ti+3] in NaAlH4

AtomisticCalculations

ThermodynamicCalculations

∆οH vs. T & [Ti+3] in Na3AlH6

ai, bi, ci—constants evaluated from experimental data (∆H, ∆S, CP)

∆οG vs. [Ti+3] in NaAlH4 & Na3AlH6


10-2

10-1

100

101

102

103

104

PH

2, atm

1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6

1000/T(K)

Na(AlNa(Al1-x1-xTiTixx)H)H44

NaNa33(Al(Al1-x1-xTiTixx)H)H66

x=0x=0

0.020.02

0.060.06

0.060.06

0.020.02

x=0x=0

Thermal Stability of Ti+3 doped NaAlH4 & Na3AlH6

• Both NaAlH4 & Na3AlH6destabilized with [Ti+3] additions (~50oC @ [Ti+3]=0.06)

• Isothermal plateau pressures predicted as a function of [Ti+3]

• Na3Al0.94Ti0.06H6 plateau pressure raised from 0.3 bar to 7 bar at 90oC

• NaAl0.94Ti0.06H4 plateau pressure raised from 10 bar to 400 bar at 90oCPredicts accessibility of full 5.5wt% H2 above 1 bar pressure!!

90oC

PH2=exp(-∆G/RT)

Na(Al1-xTix)H4=1/3Na3AlH6+xTiH2+(2/3-x)Al+(1-x)H2

Na3(Al1-xTix)H6= 3NaH+xTiH2 +(1-x)Al+(1.5-x)H2


Design Goals & System Elements

Powder expansion• ullage space• partitions and modules• deformable inclusions & structures• compaction• flow aids

Compact volume, V

Minimal weight, G

Rapid charge & discharge rate, R

Long life, L

Safe

Heat conduction enhancement• continuous (fins, metal foam, screen)• discontinuous (particles, whiskers)• compaction

Optimal DesignAccident risks• material characteristics• powder containment• proximity to water

Pressure requirement• dependent on kinetics• significant weight penalty Low Cost


Metal Hydride Systems

Inner pipeParticle filterHydride materialHeat transfer enhancementPartitionsOuter pipe & end caps

SRTC design serves as a baseline• Elements common to many designs• Efficient pressure containment• 280 Wh/kg (1.0 MJ / kg)• 420 WH/L (1.5 MJ / L)

Modifications for NaAlH4• Higher pressures• Weight reduction• Powder expansion differences


Design ComparisonsGravimetrics vs. Pressure

316 Stainless steel

System Comparison• 4.5 wt% material• 47% powder relative density• 50 atm charging pressure

440 Wh / kg 400 Wh / LCarbon fiber composite

930 Wh / kg 400 Wh / L

Composite tank necessary to achieve gravimetric goals!


Current approach tracks weight fraction of each composition

Kinetics Modeling

C1 C2 C3

NaH + Al + 3/2 H2 ↔ 1/3 Na3AlH6 + 2/3 Al + H2 ↔ NaAlH4

From Sandrock et. al.iESH ,,∆∆

iiA χ& adjusted

( ) ( ) ( )iri

i ChPgTfdt

dC **=

For C1:

( ) 12

1,

1,11

1

1 **exp χCP

PPRTEA

dtdC

e

e

r

−

−=

1

1

1

2

rr dtdC

dtdC

−=

El Osery, 1993


50g sub-scale system

Thermocouples

End cap

2” diameter tubing

Hydride powder


Thermal Conductivity/Enhancement ABAQUS simulation

Teflon

316 SS

Powder

TC input

70

60

50

40

30

Tem

pera

ture

, [de

g. C

]

5004003002001000Time, [s]

Experiment Simulation, k = 0.50 W / m C

TC input

Ball milled Albemarle powder (undoped): k = 0.35 to 0.50 W / m oC

80 C

30 CThermocouples

80

70

60

50

40

30

20100806040200

Time, [s]

tube r = 0.07 r = 0.32 r = 0.75

1/hc = 1/500

Unfilled contact resistance

C W/m50011

2 ο=ch

C W/m100011

2 ο=ch

Filled with NaAlH4

Unfilled contact resistance results

•Thermal contact resistance is significant for interference fit


System FEA Modeling ABAQUS

Vessel: 9” Dia. Vessel, 4 wt% Al foam, stainless steel tubingMedia: Albemarle NaAlH4 + 2% Ti+3

Starting state: Full discharged, 80oCCharging state: 100 bar H2 pressure, 120oC fluid flow

1.0

0.8

0.6

0.4

0.2

0.0

Com

posi

tion

fract

ion

20x103 151050Time, [s]

Compositionblue: C2red: C3

Location

solid: tube, pt Adashed: mid-plane, pt B

260 C

80 C


System Design Modeling• ABAQUS subroutine calculates hydrogen mass via integration of Ci fields.• Sensitivity study conducted for number of internal conduit passes during

charging.Temperature at t = 1400 s

0.8

0.6

0.4

0.2

0.0

Mas

s of

sto

red

H2,

[kg]

1000080006000400020000Time, [s]

Number of conduit passes:

1 2

4 16 8

30

260 C

120 C


Future Work2003-04 Milestones

1. Complete Safety Analysis2. Perform 50g H2 System Cyclic Evaluations3. Assess/Complete Thermodynamic Modeling4. Complete media cycling to assess durability.5. Complete Prototype 1kg System Design &

Fabrication6. Complete Evaluation of 1kg System Prototype

Capabilities to meet Go/NoGo criteria.

Documents

High Density Hydrogen Storage System Demonstration Using ... fileUnited Technologies Research Center Program Specifics Objective: Develop, build, bench demonstrate and deliver an in-situ