A student cleaned catalyst that was being used for a fuel cell membrane electrode assembly from a spatula. He then placed the contaminated paper towel into a waste container that contained other waste that was wet with alcohol. The alcohol reacted with the catalyst, igniting a fire within the waste container. The fire was extinguished with a beaker of water.
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
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
A solution of potassium carbonate was being drawn off to an inventory tank for a turnaround/shutdown maintenance activity at a refinery's hydrogen production unit. On the day of the incident, the solution level in the tower wasn't checked as it should have been, which resulted in hydrogen gas flowing back into the tank until the increased pressure caused the tank to explode. The direct cause of the incident was the workers neglecting to check the solution level in the tower. It is not known whether the potential for backflow of hydrogen gas into the inventory tank was understood beforehand or not.
An explosion occurred due to unexpected backflow of hydrogen gas while a solution of potassium carbonate was being drawn off to an view more
A facility experienced a major fire in its Resid Hydrotreater Unit (RHU) that caused millions of dollars in property damage. One employee sustained a minor injury during the emergency unit shutdown and there were no fatalities.
The RHU incident investigation determined that an 8-inch diameter carbon steel elbow inadvertently installed in a high-pressure, high-temperature hydrogen line ruptured after operating for only 3 months. The escaping hydrogen gas from the ruptured elbow quickly ignited.
This incident occurred after a maintenance contractor accidentally replaced an alloy steel elbow with a carbon steel elbow during a scheduled heat exchanger overhaul. The alloy steel elbow was resistant to high-temperature hydrogen attack (HTHA), but the carbon steel elbow was not. view more
A rupture occurred in a 24-inch gas line in a reformer. The pipe contained hydrogen and carbon monoxide at a pressure of about 400 psi and a temperature of 930 °C. The ruptured section of pipe had a high-temperature alloy steel outer wall, a refractory liner, and a stainless steel inner liner. The refractory lining had been repaired several times before (including three months prior to the incident) because of localized deterioration and hot spots. The repair procedure consisted of cutting a section of pipe, re-pouring the refractory liner, and patch-welding the outer wall.
The first rupture occurred when the 42-inch-long welded section of the pipe suddenly blew out. On-site employees heard a rumble and observed a flame above the ruptured pipe. Before the torch fire at the view more
An anhydrous hydrogen fluoride (AHF) lecture bottle spontaneously exploded in a laboratory. No one was injured, but the lab was extensively damaged. The lecture bottle had split along its seam. Its cap and valve assembly were located to the immediate left.
The explosion was caused by hydrogen gas pressure build up in the cylinder. AHF comes in carbon steel cylinders as a liquefied gas under a pressure of 0.9 psi at 70 oF (i.e., the vapor pressure of the liquid). Though cylinders should be passivated with fluorine, which forms a protective coating, over time AHF may slowly react with the iron in a cylinder to form iron fluoride and hydrogen gas. The generation of hydrogen gas may produce cylinder pressures as high as several hundred psi.
A person working in a hydrogen lab unknowingly closed the wrong hydrogen valve and proceeded to loosen a fitting in one of the hydrogen gas lines. The pressure in the 1/4"-diameter hydrogen line was approximately 110 psig. Hydrogen escaped from the loosened fitting and the pressure release resulted in the tubing completely detaching and falling to the floor. The person noted seeing a white stream around the hydrogen jet leak. The person noted a color change and noise change as the leak ignited (this happened in a matter seconds and he did not have a chance to react). The person left the lab and pushed the emergency stop button. Someone else pulled the fire alarm. Both of these actions were designed to close the main hydrogen solenoid (shutoff) valve. The local emergency response view more
Facility management confirmed that a hydrogen gas cylinder did not comply with the limiting condition for operation (LCO) for flammable gas control systems in the lab's safety requirements. Earlier erroneous calculations had shown that a release of the entire contents of the cylinder into the hood could not reach the lower flammability limit (LFL).
The facility manager determined that the LCO was applicable and immediately entered the action statement in the safety system, which required immediate termination of normal operations in the affected wing of the building. Because normal operations had already been terminated in the wing for HVAC maintenance, further efforts to terminate normal operations were not necessary. The hydrogen cylinder was removed from the hood, thus view more
A process area alarm activated. The alarm was caused by an instrument channel located above a reaction vessel off-gas system final HEPA filter canister, which indicated 25% of the lower explosive limit (LEL) for hydrogen. Since the only source of hydrogen is from the reaction vessel during the reaction of sodium with concentrated sodium hydroxide, the immediate actions were to shutdown the reaction process and place the facility in a safe condition.
The root cause was inadequate or defective design. Had the pre-filter drains been vented to outside the building, no hydrogen could accumulate in the process area. The corrective action for this is to complete an Engineering Task Authorization (ETA) to install a sample/drain collection system with loop seals to prevent any release of view more
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