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

Overview: A hydrogen leak and explosion occurred due to the installation of an incorrectly sized gasket at the suction line of a hydrogen compressor in a refinery hydrodesulfurization plant. The incorrectly sized gasket was mounted during the startup of the plant in 2001 and had never being inspected nor replaced.

Incident synopsis: The operating conditions were stable when the operator received an alarm indicating pressure loss in the circuit. He immediately instructed his field personnel to inspect the area. The hydrogen leak was confined inside the compressor room because the walls and roof were not provided with ventilation devices. An explosion occurred, causing two fatalities and the destruction of the compressor room and some of the surrounding area.

A sidewall burst failure of a high-pressure polytetrafluoroethylene-lined hose was experienced. The 4.0-m hose was in service for approximately two years, primarily for 70 MPa fueling of hydrogen at ambient conditions ranging from -40 C to +50 C. The total number of fills during its service life was estimated to be 150. In addition to the high-volume fill events, pressure cycling occurred as part of the routine test procedures and operational protocols. These additional pressure-cycling occurrences were approximated to be 200-250 cycles. During each filling cycle, the hose was allowed to bend during connections, as required by the situation. Failure of the hose occurred while temporarily connected to a gas booster, after 1-2 hours of service at 75 MPa. There were no tight bends in the view more

A single-stage diaphragm compressor failed during boosting of high-pressure hydrogen ground storage banks. The compressor sources hydrogen from a 44 MPa storage bank as suction and discharges it at a stop set point of 85 MPa. The compressor capacity is 0.71 m3/min (25 scfm).

The original notice of failure was through an inter-diaphragm pressure indication and alarm. There should not be any pressure build-up between the layers of the diaphragm. Upon opening, hydraulic oil was found, leading to the assumption that the hydraulic-side diaphragm was leaking. Although spare diaphragms and seals were available for on-site repair, difficulty was encountered in attempting to remove the compressor nut above the diaphragms. Similar difficulties were encountered when the unit was returned view more

An explosion at a coal-fired power plant killed one person and injured 10 others. The blast killed the delivery truck driver who was unloading compressed hydrogen gas, which is used to cool the plant's steam generators. Hydrogen deliveries are routine at the plant, occurring about once a week. Evidence pointed to the premature failure of a pressure-relief device (PRD) rupture disk, which had been repaired by the vendor six months prior to the explosion.

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

A laboratory technician died and three others were injured when hydrogen gas being used in experiments leaked and ignited a flash fire.

The incident occurred in a 5,700-square-foot, single-story building of unprotected non-combustible construction. The building was not equipped with automatic gas detection or fire suppression systems.

Employees in the laboratory were conducting high-pressure, high-temperature experiments with animal and vegetable oils in a catalytic cracker under a gas blanket. They were using a liquefied petroleum gas burner to supply heat in the process.

Investigators believe that a large volume of hydrogen leaked into the room through a pump seal or a pipe union, spread throughout the laboratory, and ignited after coming into contact with the view more

SummaryA fire occurred in a battery manufacturing plant that was about to cease operations for the night. The fire caused an estimated $2.4 million in property damage when an electrical source ignited combustible hydrogen vapors.BackgroundThe incident occurred in the forming room, where wet cell batteries were stored for charging on metal racks. The facility had a wet-pipe sprinkler system, but no automatic hydrogen detection equipment.Incident SynopsisAt 11:52 pm, a security guard on patrol noticed a free burning fire in the forming room and notified the fire department. It took fire fighters almost three hours to bring the fire under control.Although the facility was equipped with a wet-pipe sprinkler system, the forming room's branch had been disconnected 10 to 15 years before view more

Summary
A hydrogen explosion occurred at a plant, damaging a wall adjacent to the hydrogen storage assembly. The investigation revealed that the explosion was the consequence of deficiencies in components integral to the hydrogen storage assembly, and that this assembly belonged to a supplier contracted to provide hydrogen to the plant. The analysis revealed that had the supplier properly installed and maintained this equipment, this incident would have been prevented. By receiving assurance, on an ongoing basis, that the supplier was properly maintaining this equipment, the company could have also reduced the chance of occurrence of this incident.

Background
A hydrogen supplier was awarded a contract in 1990 to supply the plant with hydrogen as well as to provide view more

Incident Synopsis
During routine facility maintenance of an automatic battery charging system, 6 of 27 nickel cadmium batteries being reinstalled exploded.

Cause
Inadequate work procedures in that a probable cause was ignition of accumulated hydrogen gas by a spark generated during the replacement work, and inadequate ventilation of the battery area; a second probable cause was stopped up vent caps, resulting from contaminated electrolyte, which permitted hydrogen pressure build up to an explosive force in the 6 batteries.