A metal hydride storage system was refilled using compressed hydrogen in a closed lab environment. The tank system is an in-house development and is optimized for high hydrogen storage density and use with an air-cooled fuel cell. The system is equipped with a pressure relief valve that opens gradually at 35 bar to protect the tank from overpressure conditions. The tank itself is designed to adsorb 400 g of hydrogen at a pressure less than 15 bar.

For refueling, the secondary pressure on the compressed hydrogen supply container was set to 20 bar and the adsorption of the hydride was started without hydrogen flow limitation. Due to the exothermic nature of the hydride upon recharge, as expected a sharp increase in tank temperature was measured. The tank was uncooled because the view more

Incident Synopsis
At an offsite liquid H2 fill station, a liquid hydrogen trailer hit a gaseous H2 purge shut off valve handle. Tubing attached to the purge valve was bent on both ends but did not leak.

Cause
The driver was not sufficiently careful in approaching the liquid H2 system fill point.

A person working in a hydrogen lab unknowingly closed the wrong hydrogen valve and proceeded to loosen a fitting in one of the hydrogen gas lines. The pressure in the 1/4"-diameter hydrogen line was approximately 110 psig. Hydrogen escaped from the loosened fitting and the pressure release resulted in the tubing completely detaching and falling to the floor. The person noted seeing a white stream around the hydrogen jet leak. The person noted a color change and noise change as the leak ignited (this happened in a matter seconds and he did not have a chance to react). The person left the lab and pushed the emergency stop button. Someone else pulled the fire alarm. Both of these actions were designed to close the main hydrogen solenoid (shutoff) valve. The local emergency response view more