A closed 20-mL glass scintillation vial containing approximately 5 grams of an aluminum hydride compound ruptured and shattered, likely due to pressure buildup after 6 weeks of storage. The glass vial with aluminum hydride compound was stored inside a closed plastic box. The plastic box with vial was stored within an air-free glove box at room temperature. When the glass vial ruptured, the vial was contained within the plastic box; however, the plastic box door was forced slightly ajar. The ruptured containers and internal materials were fully contained within the glove box. No damage was observed to the glove box and no one was injured. The attached photograph shows the remains of the vial within the plastic box.
Overview: A pipe end containing fuel oil corroded at the outlet of a heat exchanger on the outlet side of a desulfurization reactor. The corroded pipe end leaked hydrogen gas, which exploded, causing oil to leak from the heat exchanger. The leaking oil developed into an oil fire, and the damage spread. The causes of the pipe end corrosion include the following:
There was a high concentration of corrosive substances in the process injection water.
The concentration of corrosive substances increased due to re-molding the heat exchangers.
The shape of the pipe cap was dead end piping.
Incident: During normal operations at a fuel oil refinery, a pipe end in a desulfurization unit developed a hydrogen leak, which led to an explosion. The pipe end was located on view more
The catalyst in a dehydrogenation reactor, which was usually operated under a hydrogen atmosphere, was changed while the reactor was isolated from the peripheral equipment by closing a 20-inch remotely controlled valve. The hydrogen pressure in the peripheral equipment was set at 20 KPaG, and the reactor was opened to the atmosphere. Anticipating some hydrogen leakage, suction from the piping was accomplished with a vacuum device and, nitrogen sealing was performed. When the piping connections were restored after changing the catalyst, flames spouted from the flange clearance and two workers were burned. One cause of the fire was poor management of the catalyst replacement process.
A catalyst exchange was carried out in a dehydrogenation view more
Hydrogen leaked from the outlet piping of a hydrogen heating furnace at a fuel oil desulfurization cracking unit during normal refinery operation. The leaking hydrogen caused a localized fire. Dilution water for cleaning polythionic acid collected in the drain nozzle after a turnaround shutdown. The chlorine concentration in this dilution water was high because its concentration in the industrial water was originally high. The chlorine in the industrial water was concentrated by the high temperature, after the plant was restarted, and stress corrosion cracking occurred. Hydrogen leaked and was ignited by static electricity or heat.
A fire occurred at the fuel oil desulfurization cracking unit of a refinery 257 hours after startup of the plant, view more
During operation of a succinic acid plant, hydrogen leaked from a mounting joint on a safety valve at the upper part of a reactor, which generated a hydrogen flame. Prior to the incident, the safety valve was removed and reattached during an inspection at a turnaround shutdown. An incorrectly sized, smaller gasket was installed on the joint, and the tightening force on the bolts was inadequate. Therefore, a gap was generated as time went by and un-reacted hydrogen leaked.
In the case of many leak tests after construction, a leak is checked by a soap test after pressurizing piping and facilities for the test. (A soap test is conducted by pouring soap suds at the place to be checked (mainly a joint part) after pressurizing. If bubbles are found, view more
During start-up operation of a high-temperature, high-pressure plant using hydrogen, hydrogen gas leaked from the flange of a heat exchanger and a fire occurred. The leakage occurred for two reasons:
Insufficient tightening torque control was carried out during hot-bolting and an unbalanced force was generated across the bolts.
A temperature rise was induced across the heat exchanger as a result of a revamping activity, during a turnaround shutdown.
Hot-bolting: In equipment and piping that operate at high temperatures, as the temperatures rise, the tightening force decreases, thus re-tightening of bolts is necessary. This work is called hot-bolting. The design conditions of the evaporator where the fire occurred were 2.4 MPaG, view more
A hydrogen leak and fire occurred due to the installation of an incorrectly sized gasket at a solvent manufacturing plant. A worn gasket was accidentally replaced with a new gasket that was smaller than the standard one, and the system could not withstand the operational pressure of the hydrogen, causing the hydrogen to leak and ignite a small fire. Furthermore, a nearby gasket was damaged by the fire, causing a larger quantity of hydrogen to leak, and the fire spread. As nitrogen was substituted for the combustible hydrogen gas in the piping at an early stage of the fire, damage was limited to the immediate area. If the hydrogen had not been quickly purged from the system, the fire damage would have been greater. It is assumed that gasket management at a turnaround view more
During transfer of liquid H2 from a commercial tank trailer to a receiving vessel, a leak developed in a bayonet fitting at the trailer/facility connection. The leak produced liquid H2 spray which enveloped the rear of the truck where the hand-operated shutoff valve was located. Emergency trained personnel, wearing protective clothing, except for proper shoes, entered the area and shut off the flow control valve. Reentry personnel suffered frost bite of their feet when shoes became frozen to the water-wetted rear deck of the truck.
A loose hose flange connection allowed leakage of cold fluid through the lubricated bayonet seal. This allowed cold fluid to contact and shrink the 'O' ring seal (made of Buna-N rubber), thus permitting view more
NaAlH4 powder mixed with hexane was placed in two metal trays and dried by placement in a glove box antechamber under vacuum. After several days, the trays were moved into the glove box main chamber. As the powder in one of the trays was being transferred to a container involving scraping of a metal sieve and metal milling balls with a metal spatula, a portion of the powder in the tray spontaneously reacted rapidly, creating a pressure pulse which cracked the window at the back of the glove box. No injuries occurred, and the glove box window was resealed using tape within one to two minutes.
Difficulties were experienced with two solenoid-operated globe valves in a charging system. When shut, the valves could not be reopened without securing all charging pumps. During a refueling outage, the two valves were disassembled and examined to determine the cause of the malfunction. It was found that disc guide assembly springs in both valves had undergone complete catastrophic failure. The springs, which initially had 25 coils, were found in sections of only 1-2 coils. Metallurgical analysis of the failed springs attributed the probable cause of failure was due to hydrogen embrittlement. The springs are made of 17-7 PH stainless steel.
Discussion with the valve manufacturer revealed that similar failures occurred on three previous occasions. These spring failures were also view more