A leaking liquid hydrogen cryogenic pump shaft during the process of filling a gaseous tube delivery trailer to 2400 psi at a liquid hydrogen transfilling location caused a series of explosions and a fire. After approximately 30 minutes of filling, the operator heard a single loud explosion and then saw flames and ripples from heat generation near the ground in the hydrogen fill area. The operator quickly actuated the emergency alarm system that shut down the cryogenic pump and closed the air-actuated valves on the cryogenic pump supply line. After this shutdown, three smaller explosions were heard as well as the sound of gas releasing from a safety relief valve. The fire department was called to the scene and participated in the final shutdown of the hydrogen system as the fire was view more
Within the International Space Station (ISS) oxygen generator, an increase in differential pressure across a pump supplying return water to a PEM electrolyzer fuel cell stack had persisted over a 4-month period and was approaching the shut-off limit for the system. This decrease in performance was suspected to be caused by water-borne catalyst fines containing platinum black and Teflon®* binder materials, shed by the fuel cell stack, and accumulated within the pump's inlet filter. Maintenance in the field was required.
The system had been designed for factory maintenance, and no contingency had been planned to handle field maintenance for such a circumstance. An initial assessment of hazards for the proposed filter maintenance raised the concern that opening the water line view more
On July 1, 2009, a plasma experiment was conducted to produce a small quantity of sodium borohydride from anhydrous sodium borate, methane, and hydrogen in an enclosed reaction chamber. The reactants were injected into an argon plasma flame to carry out the synthesis reaction.
After the run was completed, as per work control procedure, the experimenter removed the plasma torch from the top lid of the collection chamber and taped a piece of weighing paper over the opening so air would not get into the chamber and contaminate the product. The experimenter then installed a plastic glove bag over the top lid of the collection chamber and attached it just below the top lid using Velcro. Before final installation, the experimenter placed a screwdriver and a natural bristle paint brush view more
An instrument engineer at a hydrogen production facility was arresting the hydrogen leakage in tapping a pressure transmitter containing 131-bar hydrogen gas. The isolation valve was closed and the fittings near the pressure transmitter were loosened. The pressure dropped from 131 bar to 51 bar. The fitting was further loosened (though very little); the instrument tube slipped out of the ferrule and got pulled out of the fitting. With the sudden release of the 51-bar hydrogen, there was a loud pop (like a fire cracker) and the spark-proof tool was observed to have black spot on it. The volume of the hydrogen gas released was small, since it was in the tapping line only.
While performing hydrogen gas release experimentation by thermally reacting a slurry of ammonia borane powder in silicone oil in a plug flow reactor, a discharge port on the test reactor became loose. A foaming white product was leaking from the fitting and discharging in the direction of the heat tape and insulation (back over the reactor). As a result, hot, reacting slurry flowed out of the port and was exposed to air. In the presence of oxygen, the slurry ignited, producing a green flame. A small green flame was noticed at the leak site and flaming product dripped onto the hood deck surface. The flame at the end of the reactor was ~10-12 inches tall at the highest point. The flame on the deck was ~4-6 inches in height.
The incident occurred behind the lowered sashes in the view more