A rupture disc blew on a 20,000-gallon liquid hydrogen tank, causing the vent stack to exhaust cold gaseous hydrogen. Emergency responders were called to the scene. To stabilize the tank, the remaining hydrogen was removed from the tank except for a small volume in the heel of the tank that could not be removed manually. The tank vacuum was lost. Firemen sprayed the tank with water and directed a stream onto the fire exiting the vent stack. The water was channeled directly into the open vent stack, and the exiting residual hydrogen gas (between -423 F and -402 F) caused the water in the vent stack to freeze. The water freezing caused the vent stack to be sealed off, disabling the only exit for the cold hydrogen gas. After a time, the residual hydrogen gas in the tank warmed up, causing view more

Summary

A hydrogen generation plant experienced a fire and significant damage due to a concussive combustion event that started in a high-pressure hydrogen feed pipe.

System Description

A certain hydrogen plant is designed to continuously produce hydrogen at a purity of 99.75% and at a rate of 510 m3 per day. Hydrogen is produced in two banks of cells filled with a strong solution of caustic soda. Current is passed through the cells to produce hydrogen and oxygen. The oxygen is vented directly to the atmosphere, while the hydrogen is piped to the gasholder. The gasholder is a low-pressure storage vessel capable of storing 28 m3 of gas. It is constructed in two parts. The bottom section is a large round tank. The upper section is an inverted tank or bell that is view more

A fire occurred in a hydrogen storage facility. The fire was reported by an employee who saw the fire start after he had aligned valves at the hydrogen storage facility in preparation for putting the hydrogen injection system into service. The employee escaped injury because he was wearing fire-retardant protective clothing and was able to quickly scale a 7-foot-high fence enclosing the hydrogen area. The local fire brigade was dispatched and offsite fire fighting assistance was requested. Upon reaching the scene, the local fire department reported seeing a large hydrogen-fueled fire in the vicinity of the hydrogen tube trailer unit. The heat of the fire potentially endangered the nearby hydrogen storage tanks. The onsite fire department, with offsite fire fighting support, fought the view more

Hydrogen was stored in a plant in a 42 ½ ft diameter sphere made of 3/16 inch steel. The sphere was partitioned into two hemispheres by a neoprene diaphragm attached around the equator. Hydrogen was stored under the diaphragm, while the upper hemisphere contained air. An explosion-proof fan was situated in the upper portion of the sphere in order to provide a slight positive pressure on the top of the diaphragm.

When the plant was shut down for a local holiday, the fan on top of the hydrogen sphere was also stopped. During plant startup two days later, a violent explosion occurred in the sphere. The sphere shell was torn into many sections by the explosion, and some of the sections were propelled as far as 1,200 ft. Some of these sections struck flammable liquid storage tanks view more

A liquid hydrogen neutron moderator developed a leak between the canister that contains liquid hydrogen and the insulating vacuum jacket.

The moderator assembly consists of an exterior metal vacuum jacket with an interior metal transfer line and canister that contain liquid hydrogen. The moderator canister is constructed of aluminum and is approximately five inches wide, five inches high, and two inches deep. The liquid hydrogen supply lines to the moderator canister are constructed of stainless steel. The operating temperature of the moderator varies from -420 degrees Fahrenheit to a possible 300 degrees Fahrenheit. Mechanical operators discovered a leak following a cleaning operation on the moderator. The cleaning operation was performed to remove impurities that could freeze view more

While refilling the hydrogen system after an outage caused by a power failure, the excess flow valve located at the hydrogen tank tripped, but did not go fully shut.

The large valve is equipped with a small bypass valve so that the valve can be pressurized on both sides as is required before the valve can be reset. The O-ring which makes this small valve gas tight was deformed and improperly seated, thus allowing gas to flow to each side of the large valve. This permitted the valve to trip normally, but not to seat properly. The following is the manufacturer's evaluation after disassembly and inspection of the valve.

This valve was recently installed to provide excess flow protection to the underground portion of the hydrogen system piping and to provide redundant view more

A liquid hydrogen tank’s rupture disc failed prematurely, which caused the tank to vent its entire gas contents through the tank’s vent stack. Venting was very loud and formed a condensed moisture cloud visible from the top of the stack. Liquid air was also visible coming off the stack. Venting ceased after approximately 5 minutes. On-site staff called the fire department, which arrived promptly and evacuated the area. Normal operations resumed after the Fire Department was able to determine there were no unsafe conditions.

A fire erupted from a tanker truck delivering liquid hydrogen to a factory. The ignition of leaking vapors created a plume of flames that rose dozens of feet into the air. The flames receded within seconds, leaving the truck with little damage and its driver unharmed.

The truck was off-loading hydrogen into a tank behind the plant when the incident occurred. The plant reported no delays in its production. It uses the hydrogen in various processes.

On site personnel reported that hydrogen vapors released through a vent in the tank somehow ignited. The driver sealed off the vent within seconds and stopped the blaze. Fire officials and the two companies are now trying to determine what sparked the vapors. The safety equipment in place prevented the fire from spreading into view more