Post on 18-Jan-2016
1 | W. Lohstroh |San Sebastian | 14.9.2007
Complex Hydrides as Solid Storage Materials: First Safety Tests
Wiebke LohstrohMaximilian FichtnerWolfgang Breitung
2 | W. Lohstroh |San Sebastian | 14.9.2007
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
3 | W. Lohstroh |San Sebastian | 14.9.2007
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
4 | W. Lohstroh |San Sebastian | 14.9.2007
M. Fichtner et al., Nanotechnology 14 (2003) 778
M. Fichtner, Adv. Eng. Mater. 6 (2005) 443
Hydrogen absorption kinetic
100 bar H2
100 °C
5 | W. Lohstroh |San Sebastian | 14.9.2007
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
6 | W. Lohstroh |San Sebastian | 14.9.2007
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
7 | W. Lohstroh |San Sebastian | 14.9.2007
Setup of Safety Experiments
8 | W. Lohstroh |San Sebastian | 14.9.2007
High speed camera
ambient environment
9 | W. Lohstroh |San Sebastian | 14.9.2007
High speed camera
water spray
10 | W. Lohstroh |San Sebastian | 14.9.2007
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
11 | W. Lohstroh |San Sebastian | 14.9.2007
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
12 | W. Lohstroh |San Sebastian | 14.9.2007
Expulsion of the powder: IR
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
13 | W. Lohstroh |San Sebastian | 14.9.2007
Expulsion of the powder: IR
water spray environment
14 | W. Lohstroh |San Sebastian | 14.9.2007
Expulsion of the powder: IR
spark ignition
15 | W. Lohstroh |San Sebastian | 14.9.2007
Sound levels during the first ms
no ignition
Spark ignition
spray water
Pure hydrogen
opening of burst disc
16 | W. Lohstroh |San Sebastian | 14.9.2007
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!)
17 | W. Lohstroh |San Sebastian | 14.9.2007
Krzysztof ChłopekChristoph FrommenNobuko HanadaAline LéonWiebke LohstrohEva RoehmOleg ZabaraMaximilian Fichtner
Gerold SternWolfgang Breitung
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