An explosion occurred in a hydrogen liquefier/purifier commissioned in 1987, after it had previously operated safely for many years. The explosion took place in the nitrogen cold box section of the hydrogen liquefaction process in an activated carbon cold adsorber vessel. Process records showed that the explosion occurred at the beginning of the regeneration phase of the activated carbon adsorber. When the explosion took place, the outlet temperature of the activated carbon bed was still at -190C. The force of the explosion was estimated from a mapping of the debris to be between 10 and 100 kg TNT equivalent.Activated carbon is a general term that covers carbon material mostly derived from charcoal. It has an exceptionally high surface area and can adsorb large quantities of gases. It view more
A university researcher reported that a fire resulted when he scraped lithium aluminum hydride (LiAlH4) out of the glass jar in which it was contained (see attached photo). The jar had been in the laboratory since 2005 (about 6 years), so the LiAlH4 was old. The researcher was using a dry metal spatula to scrape the LiAlH4 out of the jar. A quick review of the manufacturer's Material Safety Data Sheet (MSDS) for LiAlH4 informed the researcher of its moisture sensitivity, but there was no indication of friction causing a fire. However, the supervising faculty member reported personal knowledge that friction can cause ignition of LiAlH4.
The fire was put out with an ABC extinguisher. In the attached photo, the ABC extinguishing agent is the yellow powder.
An experienced researcher with 30+ years of laboratory experience (including working with air-sensitive compounds) was disposing of a small vial of catalyst and hydride powder left in the laboratory by a post-doc. The researcher emptied the vial into a container of mineral oil inside a glove box, but a small amount of the hydride powder adhered to the wall of the vial. The vial was then removed from the glove box and brought over to a tall waste jar in the laboratory that contained isopropanol. (Isopropanol is the first (slowest-acting) pacifier used when deactivating pyrophoric hydrides.) The vial was opened and inverted over the isopropanol jar and the residue powder was tapped into the jar. There was a "small flash of flame" that quickly extinguished itself.
A trained operator was blending water, sand, anhydrite, lime, cement, pulverized fly ash, and powdered aluminum in a mixing chamber to produce material for making concrete building blocks. In the blending process, sand and water are mixed to form a slurry, and then the powders are dispensed automatically into the mix by a computer-controlled system. Finally, a slurry of glycol-coated aluminum powder is added in the last few seconds before the mix is discharged into a car, and then molds are filled from the car. Adding aluminum to the mixture results in a small amount of hydrogen gas evolution, which disperses from the car into the surrounding ventilated area and out through roof vents. In addition to being an ingredient of the mix, water also helps to keep the mixture cool.
A hydrogen leak at the flange of a 6-inch synthesis turbocharger valve in an ammonia production plant ignited and exploded. Hydrogen detectors and the fire alarm alerted the control room, which immediately shut down the plant, and the fire was then extinguished rapidly. There were no injuries caused by the accident, since the operator heard a wheezing sound and was able to run away just before the explosion occurred. The leaking gas was composed of 70% hydrogen at a flow rate of 15,000 cubic meters per hour. Property damages in the turbocharger included electrical cabling, melted siding, and heavily damaged pipes. The ammonia plant was shut down for more than a month.Five days before the incident, a problem with the CO2 absorber column led operators to open the vent downstream of the view more
During restart of an ammonia production plant, syngas (50% hydrogen mixed with methane, ammonia, and nitrogen) leaking from a flange directly downstream of the synthesis reactor ignited. The plant had been shut down for about 90 minutes due to a technical problem. Alerted by the plant fire alarm, the operator activated the emergency shutdown, which isolated and depressurized the synthesis loop. Steam was sprayed onto the leak site to dampen the fire, which was brought under control 55 minutes later. Property damages included pipe insulation, the reactor's protective shutters, concrete fireproofing of the reactor structure, and instrumentation cables within 3 meters of the leak site. The flames did not affect the synthesis reactor itself, which was protected by a deflector. The view more
Operators in a powdered metals production facility heard a hissing noise near one of the plant furnaces and determined that it was a gas leak in the trench below the furnaces. The trench carried hydrogen, nitrogen, and cooling water runoff pipes as well as a vent pipe for the furnaces.
Maintenance personnel presumed that the leak was nonflammable nitrogen because there had recently been a nitrogen piping leak elsewhere in the plant. Using the plant's overhead crane, they removed some of the heavy trench covers. They determined that the leak was in an area that the crane could not reach, so they brought in a forklift with a chain to remove the trench covers in that area.
Eyewitnesses stated that as the first trench cover was wrenched from its position by the forklift view more
A gas mixture cylinder was connected to a Fourier Transform Infrared (FTIR) Spectrometer to purge residual carbon dioxide and water vapor. A staff member was preparing to use the FTIR instrument. Prior to use of the instrument, it must be purged with dry nitrogen to remove residual carbon dioxide and water vapor. When the gas mixture reached the instrument's globar (resistively heated ceramic) heat source, a localized explosion occurred. No injuries resulted from the explosion but the spectrometer housing was heavily damaged. The internal components, including the optics and computer hardware, appeared to be in good shape.
A mixture of hydrogen and nitrogen was inadvertently connected for the purging rather than dry nitrogen. The staff member, even though an expert in the view more
A significant hydrogen leak occurred during refueling of the onboard hydrogen storage tank of a fuel cell-powered lift truck while it was completely depowered. The in-tank shutoff solenoid valve had recently been replaced, and this was the initial refueling event after the replacement. The fuel zone access panel was removed to allow constant visual leak checking with Snoop leak-detection fluid. The event occurred during the final pressure testing of the repaired system when an O-ring failed at approximately 4500 psi, releasing the entire contents of the hydrogen tank in about 10 minutes. The dispenser hose/nozzle was immediately disconnected, and the leak location was quickly isolated to the tank/valve interface. A 30-foot boundary around the lift truck was cleared of personnel and view more
A fuel cell forklift operator stated that he observed a "ball of fire" coming from the left side of the forklift that seemed to flash and extinguish. Investigators found no external signs of a fire, but the forklift would not start. The fuel cell power pack access panel was removed to enable investigators to search for any internal signs of a fire. Some areas inside the fuel cell stack appeared to have experienced an electrical arc or some type of overheating. All connections were verified to be tight and secure. The internal fuel cell stack circuit board cover was then removed, and the circuit card on top of the stack also showed signs of overheating. After the fuel cell stack circuit board was removed, a broken drill bit was discovered on top of the fuel cell stack plates. view more