1. 1 | W. Lohstroh |San Sebastian | 14.9.2007 Complex Hydrides as Solid Storage Materials: First Safety Tests Wiebke Lohstroh Maximilian Fichtner Wolfgang Breitung

2. 2 | W. Lohstroh |San Sebastian | 14.9.2007 H 2 (lq)H 2 (200 bar) 4 kg H 2 Complex Hydrides Mg 2 NiH 4 metal Hydrides LaNi 5 H 6 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. 3 | W. Lohstroh |San Sebastian | 14.9.2007 Hydrogen Storage in Complex Hydrides NaAlH 4  1/3 Na 3 AlH 6 + 2/3 Al + H 2 3.7 wt%  NaH + Al + 3/2 H 2 1.8 wt% 0.87 nm Ti-cluster O. Kircher, A. Leon, M. Fichtner

4. 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 H 2 100 °C

5. 5 | W. Lohstroh |San Sebastian | 14.9.2007 Complex Hydrides Hydrogen release reaction: NaAlH 4  1/3 Na 3 AlH 6 + 2/3 Al + H 2  NaH + Al + 3/2 H 2 Operating temperatures: 100 – 150 °C, 0 – 100 bar H 2 nano –scale powder particle size ~ a few 100 nm Reaction with water / oxygen: reaction products, e.g. : NaOH, Al 2 O 3, NaO x, NaOH ·yH 2 O, Al 2 O 3 ·zH 2 O  exothermic  H 2 release high reactivty with oxygen / water high energy content large surface area in combination with pressurized H 2

6. 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 NaAlH 4 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 H 2

7. 7 | W. Lohstroh |San Sebastian | 14.9.2007 Setup of Safety Experiments

8. 8 | W. Lohstroh |San Sebastian | 14.9.2007 High speed camera ambient environment

9. 9 | W. Lohstroh |San Sebastian | 14.9.2007 High speed camera water spray

10. 10 | W. Lohstroh |San Sebastian | 14.9.2007 Expulsion of the powder: Visible  no ignition  fine distribution of powder which fell to ground  material 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/ s  no measureable pressure loads

11. 11 | W. Lohstroh |San Sebastian | 14.9.2007 Expulsion of the powder: IR  powder emitted at 130°C  no heating development in powder cloud ambient environment water spray environment  temperature loads along the jet axis  T  500 °C at the center of the cloud  H 2 gas from reactor dispersed before reaction started

12. 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 cloud  H 2 gas from reactor takes part in the reaction spark ignition water spray environment  temperature loads along the jet axis  T  500 °C at the center of the cloud  H 2 gas from reactor dispersed before reaction started

13. 13 | W. Lohstroh |San Sebastian | 14.9.2007 Expulsion of the powder: IR water spray environment

14. 14 | W. Lohstroh |San Sebastian | 14.9.2007 Expulsion of the powder: IR spark ignition

15. 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. 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. 17 | W. Lohstroh |San Sebastian | 14.9.2007 Krzysztof Chłopek Christoph Frommen Nobuko Hanada Aline Léon Wiebke Lohstroh Eva Roehm Oleg Zabara Maximilian Fichtner Gerold Stern Wolfgang Breitung People…