Cooling things down. Water from fire hoses sprays on a hydrogen delivery truck and the surrounding area to keep the area cool after the explosion. A prompt response. A fireman walks through debris near a hydrogen delivery truck after the explosion. The local fire department arrived quickly on the scene to assist the other emergency response teams in fighting the fire and aiding injured workers. In the aftermath of the incident at the Muskingum River Power Plant, AEP personnel conducted their own examination into the cause of the explosion.
Due to the fatality and the injuries sustained by workers at the facility, the U. The device had been replaced by the hydrogen vendor several months prior, when the vendor was on-site to make repairs related to an apparent leak. The replacement relief device assembly did not have a fusible plug to support the disc.
When the rupture disc failed, the disc, or a piece of fusible plug left in the vent pipe during the replacement several months prior to the explosion, penetrated a bend in the piping, permitting the hydrogen to vent lower down in the area of the tanks as well as up the normal vent path, McCullough explained.
OSHA brought enforcement actions against the involved entities as a result of the findings from its investigation of the incident. Those actions initially consisted of 18 citations, nine each against the hydrogen vendor and Ohio Power Co. After an informal conference, the number of citations against each company was reduced to eight.
Most of the citations were directed at the design and construction of the hydrogen system. After the incident, AEP took corrective actions to guard against future problems related to the handling of hydrogen at the plant. AEP has made other changes in plant operations to further ensure that no more hazardous incidents occur at the facility. The cylinders have been moved away from spaces occupied by people, and the structure is protected from vehicle encroachment and ignition sources.
Despite the large number of systems that use pressurized hydrogen to cool generators, for the most part, few incidents or problems occur. However, given the inherently hazardous properties of hydrogen, plant staff working with this flammable material need to regularly review both the equipment and handling procedures to verify that there are no problems.
This case history is intended to be helpful to personnel who deal with hydrogen used to cool the generators at their power plants. Proper management, including safe equipment design and construction and correct procedures for handling hazardous materials, can ensure safe results in dealing with this useful substance. View more. Facebook Twitter LinkedIn. Defense Daily subscriber and registered users, please log in here to access the content.
Get a Free Trial Here. At present, it is hard to tell if there is a hydrogen leak because it has no odor to it. Hydrogen is a very light gas. There are no known odorants that can be added to hydrogen that are light enough to diffuse at the same rate as hydrogen.
In other words, by the time a worker smells an odorant, the hydrogen concentrations might have already exceeded its lower flammability limit. 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 free to move within the main tank as pressure increases or decreases.
The main tank is filled with water to form a water seal. Hydrogen from the cells enters the gasholder above the water line, causing the bell to rise. The purity of the hydrogen is monitored between the cells and the gasholder.
If purity falls below Hydrogen is drawn from the gasholder by the duty compressor via the gas dryer and the filter. It is compressed to The plant contains four storage banks capable of storing liters per bank. Each bank consists of 16 cylinders. Each cylinder is fitted with an overpressure protection device called a "bursting disc". One afternoon, an assistant operator attended the hydrogen generation plant as part of a routine plant inspection.
The plant was functioning correctly and no obvious problems were noted. Approximately one hour later, a large explosion was heard by a contractor in the contractor amenities area and the remaining staff in the administration building.
Calls were received soon after by the duty shift manager advising him that there was a fire at the hydrogen generation plant. Visual inspections of the plant found the high-pressure pipe work had ruptured or parted at the following locations:. Between two valves adjacent to a compressor At the pressure regulating valve near the compressor room Above the 'B' HP dryer At the inlet to the 'B' bank manifold At various bottle fittings in 'B' bank.
Twelve of the sixteen B bank cylinders and six cylinders on C bank had been affected by the heat of the fire. Many of the copper vent pipes from the cylinders to atmosphere were discolored or melted indicating that many of the cylinder bursting discs had ruptured. The vacuum and purge pipe work around B and C banks had been destroyed by the fire. The cladding at the eastern end of the building had been blown out above two storage banks. Debris from the site was distributed for 20 meters.
Explosions in the HP hydrogen feed pipes caused the failure of welds and connections at the storage banks, allowing hydrogen gas to be released in large quantities from the B and C storage banks.
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