The sensing diaphragm of a pressure transducer (PT), as supplied on an outdoor hydrogen compressor, unexpectedly ruptured and released approximately 0.1 kilograms hydrogen to atmosphere from the compressor discharge line. At time of incident, personnel nearby were alerted by a loud 'pop' and dust disturbance. Simultaneously, the facility monitoring system detected loss of the PT signal and initiated equipment shutdown. Facility personnel then closed isolation hand valves to stop the leak, locked and tagged out the equipment, and view more
During inspection of a hydrogen make-up compressor, it was discovered that a 1/4” stainless steel screw and nut that mounted a temperature gauge to a stainless steel pipe was resting against the side of a schedule 160 high-pressure hydrogen pipe. Constant vibration of the process equipment had caused the bolt to rub a hole in the high-pressure suction piping, resulting in the release of make-up hydrogen. The pipe was out of sight, and the problem was identified by an employee who heard the whistling sound of escaping hydrogen. The compressor was taken offline and depressurized.
The System Shutdown logic activated and the compressor automatically shut down on high vibration. When the operator investigated the unplanned shutdown, two broken compressor head fasteners were noted lying on the deck.
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
Hydrogen and chlorine concentrations at a certain plant are measured once each shift. On the morning of the explosion, the hydrogen concentration in the chlorine header leaving the cell bank was 0.47 percent. After passing through the chlorine coolers and liquid/gas separators, the hydrogen concentration of the gas streams increased to 2.5-3.2 percent H2, i.e., 63-80 percent of the lower flammability limit.
About 5 hours after the measurements were made, the DC power to the electrolysis cell bank was shut down because of intermittent power supply problems. At that time, a low-order explosion was heard from the chlorine dryer area of the plant. Thirty seconds later, chlorine gas began escaping from the chlorine header pumps, and another explosion occurred in the electrolysis cell view more
A hydrogen compressor had been shut down for repairs and was being put back into service when an explosion occurred, resulting in property damage. The compressor was equipped with interchangeable intake and outlet valves.
The discharge valve was installed in the intake valve position, causing the cylinder head to blow off and release H2 to the atmosphere. The ignition source was not indicated.
A H2 air explosion occurred near a H2 compressor, located outside. Gaseous H2 had been released from a vent stack when a relief valve was actuated. The source of ignition was not known, but considerable damage was inflicted onto the system by the ensuing fire and explosion. Following the explosion, the shut-off valves were closed and the system was vented.
Two relief valves were located in the 3,000 psig system downstream of a 5,000/3,000 regulator. The relief valves were sized to handle substantially different flows. (One was designed for another program.) The relief valve was believed to have opened when the pressure setting was being increased from 2,700 to 2,900 psig. The accuracy of the 5,000 psig gauge used to control the dome of the 5 view more
The malfunctioning of the non-return valve of the hydrogen compressor caused the pressure between the hydrogen bottle and the compressor to rise up to the maximum allowed pressure of 275 barg. As a consequence, as foreseen by the safety system, the rupture disk of the safety valve broke and the hydrogen content of the gas bottle and the pipe section involved was released on top of the building. The flame was seen for a very short period by a guard, and could have been caused by the following series of events:
Expansion of hydrogen at the end of the exhaust pipe.
Consequent mixing of hydrogen and air up to a near-stoichiometric mixture and increase of gas temperature.
Mixture ignition due to sparks from static electricity generated by gas molecule friction against view more
A vehicle fill depleted the high-pressure hydrogen inventory. The compressor turned on to refill the storage by compressing 60 psig gas from a liquid hydrogen tank up to the 5500 psig storage pressure. After running about 2 hours, a crankshaft bearing started to fail. This allowed greater movement of the shaft, which led to a shaft seal leaking hydrogen. The compressor shut down on low suction pressure and then the system was shut down using the e-stop by the emergency responders.
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