Hazard assessment of complex hydrides as hydrogen storage materials

• Published in: International journal of hydrogen energy Vol. 34; no. 7; pp. 3210 - 3218
• Main Authors: Tanaka, H., Tokoyoda, K., Matsumoto, M., Suzuki, Y., Kiyobayashi, T., Kuriyama, N.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-04-2009; Elsevier
• Subjects: Alanate; Alloys; Alternative fuels. Production and utilization; Amide-based material; Applied sciences; Burning rate; Clouds; Containers; Dust cloud explosion; Energy; Exact sciences and technology; Explosions; Fuels; Hydrides; Hydrogen; Hydrogen storage; Hydrogen storage materials; Lithium borohydride; Materials handling; United Nations recommendations; Alanate; Dust cloud explosion; Lithium borohydride; United Nations recommendations; Amide-based material; Burning rate; Hydrogen storage; Alloys; Explosions; Hydrides; Combustion velocity; Lithium Hydroborates; Comparative study; Lithium hydride; Hazard; Handling
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2009.01.064

Hydrogen storage materials containing NaAlH
4, LiNH
2, Mg(NH
2)
2, LiH and LiBH
4 were subjected to standardized safety tests in order to assess the potential hazards caused by the environmental exposure of these materials. All the materials were judged ‘flammable’, ‘pyrophoric’ and ‘water-reactive’, resulted in being classified as the United Nations Packing Group I, the most stringent category of container regulations in transporting these materials. A small spark energy (1.4
mJ) can trigger an intense dust cloud explosion of the Mg(NH
2)
2
+
LiH system of which the minimum explosive concentration was determined to be 90
mg
dm
−3. Although this value is lower than those of the hydrogen storage alloys, the minimum explosive concentration of complex hydrides can be comparable to the alloys if expressed in terms of the amount of stored hydrogen in the material. Also examined was the eruption test, a non-standard test, in which the sample powder was pushed out of a container into the atmosphere by pressurized H
2. Despite the pyrophoricity, we observed only one explosion of the Ti-doped NaAlH
4 in dozens of trials using all the materials. A comparison with other materials points to the inevitability of more cautious measures than metal hydrides when handling these complex hydrides.