A petroleum refinery experienced a catastrophic rupture at one bank of three heat exchangers in a catalytic reformer/naphtha hydrotreater unit because of high temperature hydrogen attack (HTHA). Hydrogen and naphtha at more than 500F were released from the ruptured heat exchanger and ignited, causing an explosion and an intense fire burned for more than three hours.

The rupture fatally injured seven employees working in the immediate vicinity of heat exchanger at the time of the incident. The workers were in the final stages of a start-up activity to put a parallel bank of three heat exchangers back in service following cleaning. Such start-up activities had resulted in frequent leaks and occasional fires in the past and should have been considered as hazardous and nonroutine. view more

A chemical plant experienced a valve failure during a planned shutdown for maintenance that caused hydrogen to leak from a valve and catch fire. Four chemical reactor chambers in series were being emptied of liquid using hydrogen gas as part of a maintenance procedure. Two heater valves were opened allowing 3000 psi hydrogen to flow in reverse direction to purge the reactor system for approximately 25 minutes. At completion of the purging process, a "light" thud was heard as the reactor empty-out valves are being closed. Smoky vapor was observed coming out of one of the reactor empty-out valves and the valve closing was stopped by the operator. The operator summoned a second operator for help at which time a second "loud" thud was heard with a much larger light and view more

A pressure relief device (PRD) valve failed on a high-pressure storage tube at a hydrogen fueling station, causing the release of approximately 300 kilograms of hydrogen gas. The gas ignited at the exit of the vent pipe and burned for 2-1/2 hours until technicians were permitted by the local fire department to enter the station and stop the flow of gas. During this incident the fire department evacuated nearby businesses and an elementary school, closed adjacent streets, and ordered a high school to shelter in place.

There were no injuries and very little property damage. The corrugated roof on an adjacent canopy over a fueling dispenser was slightly singed by the escaping hydrogen flame, causing less than $300 in damage.

The station's operating systems worked as view more

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.

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.

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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