A hydrogen leakage caught fire in the hydrogen compressor area of the continuous reforming unit. The reforming unit and the hydrocracking unit were immediately stopped. The hydrogen flow was cut off, a protective combustion was carried out and the fire was completely extinguished after approximately 20 minutes, with no casualties. The cause of the accident is being investigated.

The broke out at a hydrogen compressor of the reforming unit of the refinery. Following the safety procedures, the emergency stop of the unit was activated and the unit was decompressed using a safety flare. The emergency plan was kept for an hour. A security perimeter is in place. The isolation of the compressor was started automatically. The isolation of the discharge circuit was successful, but the suction circuit could only be partially closed due to a block of a valve. The operators then closed manually the suction valve, by removing the excess of grease that had been applied to it.

Around 4 a.m., a major leak occurred at the outlet of the diesel hydrodesulfurization furnace in a refinery. The goal of this unit is to lower the sulfur content of diesel fuels produced in other units, by a catalytic reaction in the presence of hydrogen. At the moment of the leak the furnace was restarting. The alarms of the temperature sensors at the oven outlet were triggered. At 4:08 a.m., the operator shut down the hydrogen compressors and diesel charging pumps, closed the supply valves and called the emergency status. The first emergency operation was to decompress the unit.

A gas mixture (25% nitrogen, 73% of hydrogen, 2% methane) leaked, due to the ejection of the check valve from its connection with the inlet pipe. A large amount of the gas mixed with air and ignited, probably due to sparks generated by the ejected check hitting a metal pipe. It followed an explosion. Its pressure wave hit a gas pipeline causing its fracture and a fire. After about 1 hour and 30 minutes the fire was under control. The shockwave from the explosion caused a gas pipe at the back of the workshop to crack and leak, causing a large fire.

The vessel affected by the incident was a gas storage used for the desulfurisation process. The desulfurization gas had high hydrogen content. The vessels had cracks in the upper transverse fillet welds at the gas inlet which caused low stress brittle fractures. The cracks had been found during the maintenance, but not fixed. This eventually caused a gas release. Approximately 2.5 hours after that a leak was detected and reported, a first explosion occurred.

The incident affected the raw material buffer tank (design pressure 0.38 MPa) of a diesel hydrogenation unit in a refinery. This buffer tank is located between the hydrogenation reactor and the raw material storage tank. During pressure fluctuations in the lubricating oil system of a hydrogen compressor, the operator handled the situation improperly, resulting in an abnormal shutdown of the compressor, causing the hydrogen feed pump to interlock and stop.After the pump interlocked, the outlet valve was not closed in time and the two check valves failed.

The incident occurred in a catalytic reforming unit. At 13:41, a leak occurred at the 90 elbow of a pressure pipe containing a mixture of hydrogen and naphtha. This pipe was located between the pre-hydrogenation heat exchanger and the pre-hydrogenation product tower heat exchanger. The flammable material leaking from the pipe burst into flames, and at 13:51 and 14:21 there were two more explosive combustions.

In a residual-oil hydrotreatment unit (also called residual oil hydrogenation) plant, a hydrogenation unit caught fire with a huge bang, followed by a fireball in the form of a mushroom cloud. Black smoke began to billow up in the sky and was clearly visible from several kilometres away

In a refinery, a fire occurred at a new reactor for the vacuum distillate hydro-desulfurization unit. Internal gas (hydrogen, hydrocarbon, etc.) blew from a flange of upper piping in the reactor. It ignited producing 0.5-2 meters high flames.

At around 9:15 a.m., during a routine inspection, a flame was observed at the bottom flange of a reactor in a refinery. A few moments later, sensors near the leak detected a rise in temperature.The facility was shut down in accordance with emergency procedures. The sprinkler system was triggered to protect the equipment. The rapid decompression of the plant towards the safety flare reduced the leak flow rapidly. At 10:12 am, the fire was extinguished.