FUNDAMENTAL SAFETY TESTING AND ANALYSIS OF HYDROGEN STORAGE MATERIALS & SYSTEMS D. Anton, D. Mosher, W. Lohstroh, M. Fichtner, N. Kuriyama, E. Akiba, R. Chahine, D. Dedrick

Hydrogen Storage Compressed H2 Gas Cryogenic Liquid H2 5-10 ksi pressures in graphite fiber reinforced epoxy composite tanks Cryogenic Liquid H2 Ambient pressure ultra-insulated containers with bleed off device Compressed/Cryogenic H2 Cryogenic Liquid H2 in a high pressure tank to minimize boil-off Adsorption Utilizes physisorption on ultra-high surface area species. Currently used at LN2 temperatures. Absorption Utilizes chemisorption in metal, organic or complex compounds

Typical Chemisorption Reactions LaNi5H6  LaNi5 + 3H2 Mg2NiH4  Mg2Ni + 2H2 Metal Hydrides NaAlH4  1/3Na3AlH6 + 2/3Al + H2  NaH + Al + 3H2 Complex Metal Hydrides 2LiBH4 + MgH2  2LiH + MgB + 4H2 8LiH + 3Mg(NH2)2  Mg3N2 + 4Li2NH + 8H2 Destabilized Complex Metal Hydrides AlH3  Al + 3/2H2 NH3BH3  BiNjHk + xH2 Chemical Hydrides

US-DoE Technical Targets 2007 2010 2015 Wt % H2 (Useable) 4.5 6 9 Vol. Cap. (kg H2/L) 0.036 0.045 .081 Cycles 500 1000 1500 Minimum rate (g/s)/kW .02 Minimum/Maximum pressure (atm) [FC] 8/100 4/100 3/100 Minimum/Maximum ambient temperature (°C) -20/50 -30/50 -40/60 Start time to full flow (s) 4 0.5 System fill time (min) 10 3 2.5 Safety Meet or exceed applicable standards

Objective To fundamentally understand the safety issues regarding solid state hydrogen storage systems through: Development & implementation of internationally recognized standard testing techniques to quantitatively evaluate both materials and systems. Determine the fundamental thermodynamics & chemical kinetics of environmental reactivity of hydrides. Develop amelioration methods and systems to mitigate the risks of using these systems to acceptable levels.

Task 1: Standard Tests DOT/UN Doc., Recommendations on the Transport of Dangerous Goods, Manual of Tests and Criteria, 3rd Revised Ed., ISBN 92-1-139068-0, (1999). Flammability Flammability Test Spontaneous Ignition Burn Rate Water Contact Immersion Surface Exposure Water Drop Water Injection Mechanical Impact Expansion Standard Test Method for Pressure and Rate of Pressure Rise for Combustible Dusts (ASTM E1226) Pmax & (dP/Dt)max Min. Exp. Conc. Min. Ignition Energy Min. Ignition Temp. Min. Dust Layer Ignition Temp.

Task 2: Thermodynamics & Chemical Kinetics Quantitative studies will be performed to understand the chemical kinetics and thermo-chemical release of these reactions with air, oxygen and water as both liquid and vapor as a function of temperature.

Task 3: Risk Mitigation System risk analyses will be performed and methods of mitigating these risks including exposure to air and humidity will be investigated. No Mitigation With Mitigation

Task 4: Prototype System Testing Evaluation tests on risk mitigations strategies will be performed on sub-scale prototype storage systems to validate their efficacy.

Materials Test Plan NaAlH4+2%TiCl3 LiH+MgNH2 Mg2NiH4 LaNi5H6 2LiBH4+MgH2 NH3BH3 Activated Carbon AlH3 Materials Prep Plan Use Particle Size & Packing Discharge State Fully Charged Partially Discharged Fully Discharged

UTC 1st Prototype 1kg H2 Storage System 316 SS tubing for ParaTherm MR oil 4% dense aluminum foam with 50% dense Ti catalyzed NaAlH4 powder 316 SS liner 316 sintered SS filter 316 SS end closure to facilitate loading and inspection One end closed carbon fiber composite containment Rated to 1500psi Under DoE sponsorship, UTRC is designing and fabricating the first hydrogen storage system based on an alanate formulation having 1 kg H2 storage capacity. Utilizing alanate compositions as the hydrogen storage media requires many new heat, mass transfer and manufacturing techniques to be employed Novel design concepts and methods such as the Convex Hull approach are being used in this liquid/solid heat exchange application to rapidly obtain optimal design and trade factors.

Burn Rate Test Partially Discharged CCH#0-33 0 sec. 2.97 6.90 11.09

Water Drop Test Partially Discharged CCH#0-33 0 sec. 0.11 0.12 0.15

Water Drip Partially Discharged CCH#0-33 0 sec. 0.14 0.17 30.03

Flammability Test Results (DOT/UN) Class 4.3, Packing Group II

Air Exposure Test Partially Discharged CCH#0-33 0:00 min. 24:05 80oC 25:10 smoke observed 26:55 fire 34:15 max fire

Gasoline Burn Rate 0 sec. 0.03 0.75 0.88

Dust Explosion Test Results (ASTM E1226, E1515, E2019 & E1491) Test Materials Reference Materials NaAlH4 NaH+Al Pitt. Seam Coal Dust Lycopodium Spores Pmax bar-g 11.9 8.9 7.3 7.4 Rmax bar/s 3202 1200 426 511 Kst bar-m/s 869 326 124 139 Dust Class St-3 St-1 MEC g/m3 140 90 65 30 MIE mJ <7 110 17 Tc oC 137.5 584 430 Pmax = maximum explosion pressure, Rmax = pressure rise maximum, Kst = maximum scaled rate of pressure rise, MEC = minimum explosive concentration, MEI = minimum spark ignition energy, Tc = minimum dust cloud ignition temperature

Communication A WEB site will be established to communicate finding and results to the general public as expeditiously as possible.

Conclusion The risks associated with manufacturing, handling, utilization and disposal of solid state hydrides needs to be quantitatively identified. A thorough risk assessment of solid state hydrogen storage materials and systems needs to be performed. Engineering risk mitigations strategies need to be identified and tested to bring the risks to tolerable levels for commercial application.