1 | w. lohstroh |san sebastian | 14.9.2007 complex hydrides as solid storage materials: first safety...

1 | W. Lohstroh |San Sebastian | 14.9.2007

Complex Hydrides as Solid Storage Materials: First Safety Tests

Wiebke LohstrohMaximilian FichtnerWolfgang Breitung


H2 (lq) H2 (200 bar)

4 kg H2

Complex Hydrides

Mg2NiH4

metal Hydrides

LaNi5H6

Hydrogen Storage for Mobile Applications

L. Schlapbach and A. Züttel, Nature 414 (2001) p353

high volumetric and gravimetric storage density

working temperature T< 150 °C

Fast kinetics for loading & unloading

Safety

Production costs


10 100 1000 10000 100000

0

20

40

60

80

100

2 mol%TiCl

3

1.8 mol%Ti-cluster

5 mol%Ti-cluster

4

170 °C

150 °C

H2

deso

rbed

[%]

Time [s]

Hydrogen Storage in Complex Hydrides

NaAlH4 1/3 Na3AlH6 + 2/3 Al + H2 3.7 wt% NaH + Al + 3/2 H2 1.8 wt%

0.87 nm0.87 nm

Ti-cluster

O. Kircher, A. Leon, M. Fichtner


M. Fichtner et al., Nanotechnology 14 (2003) 778

M. Fichtner, Adv. Eng. Mater. 6 (2005) 443

Hydrogen absorption kinetic

100 bar H2

100 °C


Complex Hydrides

Hydrogen release reaction:

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

NaH + Al + 3/2 H2

Operating temperatures:100 – 150 °C, 0 – 100 bar H2

nano –scale powderparticle size ~ a few 100 nm

Reaction with water / oxygen:

reaction products, e.g. : NaOH, Al2O3, NaOx, NaOH ·yH2O, Al2O3 ·zH2O

exothermicH2 release high reactivty with oxygen / water

high energy contentlarge surface area

in combination with pressurized H2


Disk bursts at p = 10 bar

Material shot into the environment

SS-Tube filled with Ti-doped NaAlH4

Burst Disk

Operation: T 130 °C

P rises

Simulation of a tank failure

Experiments(i) expulsion of the powder in ambient air

(ii) expulsion of the powder in ambient air and ignition with an electric spark

(iii)expulsion of the powder in spray water environment

repeat (ii) with equivalent amount of gaseous H2


Setup of Safety Experiments


High speed camera

ambient environment


High speed camera

water spray


Expulsion of the powder: Visible

no ignition fine distribution of powder which fell

to groundmaterial still active after experiment,

e.g. reacted with water

ambient air water spray environment

ignition at borders of the powder / gas cloud

turbolent deflagration flame speeds: 2 – 13 m/ sno measureable pressure loads


Expulsion of the powder: IR

powder emitted at 130°Cno heating development in powder

cloud

ambient environment water spray environment

temperature loads along the jet axisT 500 °C at the center of the cloudH2 gas from reactor dispersed before

reaction started



ignition temperature load mainly along the jet

axis temperatures above 500 °C in center

of the cloudH2 gas from reactor takes part in the

reaction

spark ignition water spray environment

temperature loads along the jet axisT 500 °C at the center of the cloudH2 gas from reactor dispersed before

reaction started



water spray environment



spark ignition


Sound levels during the first ms

no ignition

Spark ignition

spray water

Pure hydrogen

opening of burst disc


Conclusions

No reaction when powder is expelled into open air

Ignition of the powder / hydrogen mixture when an external source is

provided (water, electric spark)

Under these experimental conditions mainly thermal loads along the jet

axis. No signifcant pressure loads were detected.

Future experiments

Test of expulsion into media (water or oil bath)

Test different materials (and loading states!)


Krzysztof ChłopekChristoph FrommenNobuko HanadaAline LéonWiebke LohstrohEva RoehmOleg ZabaraMaximilian Fichtner

Gerold SternWolfgang Breitung

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1 | w. lohstroh |san sebastian | 14.9.2007 complex hydrides as solid storage materials: first safety...

Documents

lohstroh san sebastian

distribution of powder

cloudh2 gas

pressurized h2

gaseous h2

high speed camerawater

c fast kinetics

spray water environmentrepeat