During a leak test performed on a new retention basin of a chemical plant, one of the walls of the structure collapsed on a rack of 4 pipes located nearby and caused the rupture of the supports and deformation of the pipes. 1,500 m3 of water was released into the environment. A small leak of hydrogen was detected. Site crews, assisted by firefighters on the platform, isolated and decompressed the pipes. The isolation of the hydrogen pipeline resulted in the shutdowns of 2 units in nearby refineries.

The gas leak containing hydrogen (H2) and hydrogen sulfide (H2S) occurred at the upper isolation valve located at a high-pressure separator (300 bar) of an oil production unit in a refinery. DESCRIPTION of the PROCESSAfter hydrocracking under high pressure and temperature, the oil viscosity is adjusted by means of reaction with a catalyst, hydrogen and a load of distillates. At the outlet, the high-pressure separator enables gases to be separated from liquids, with the latter channelled towards the low-pressure section by opening a valve.

The fire occurred around 13:20 on three cells of the chlorine manufacturing unit. A leak of hydrogen in the electrolysis room was at the origin of the fire; the ignition of the H2 cloud caused a noticeable noise outside the site.The emergency plan was initiated; the gas alert resulted in the confinement of personnel located in the area of the site concerned.

A deflagration occurred at a chemical plant during a synthesis operation involving sodium tri-acetoxy-borohydride inside a 5,300-litre reactor. Around 5:30 pm, the technician observed that the acetic acid intake pipe was blocked. After opening the manhole with a wooden pole, the shop foreman dropped the stalactite of solidified acetic acid in the reactor: the resulting blast severely burned the foremans face.The event was caused by ignition of the hydrogen produced from the dropped quantity of acetic acid.

The leak ignited at the seal located between the bottom and the body of a heat exchanger of a desulfurization unit of a refinery. The fire is alimented by the leaking fuel under pressure for about twenty minutes causing the emission of a plume of black smoke. The operation of decompression of the unit is delayed by the malfunction of an automated system. Nevertheless, when finally successful, it allows the fire to be controlled and then completely extinguished after emptying the reactor located upstream (morning of the following day).

A sudden failure occurs on a hydrogen line of a refinery desulfurization unit. The equipment is located between a hydrogen compressor and its overpressure protection valve. It is isolated automatically.The bursting of the pipe is due to its corrosion: a thick loss of thickness extends over 300 mm. The presence of a bend at a low point on a line without circulation led to the accumulation of deposits initiating a corrosion mechanism.The operator modifies the layout of the piping to avoid low points.

A fire broke out at a flange of a heat exchanger used in the catalytic reforming unit of a refinery. This exchanger makes it possible to heat the load of heavy oil and hydrogen by recovering the heat of the load already passed through the reactors. No flame and smoke were visible from the outside. The unit was stopped, depressurised and cooled with water and foam, waiting for the complete depressurization. The fuel supply was stopped and the fire, no longer fed, was brought under control around 22:30. Firefighters were alerted but not a request to intervene.

The explosion occurred during repair work on a boiler. A technician had previously descaled the device using hydrochloric acid, after which he performed the neutralisation step with soda and drained the passivated acid. The significant scaling on the boiler required a second acid injection, followed by welding work, but this time the rest of the acid had not been drained from the boiler. Hydrogen emitted by a metal + acid reaction was the cause of this accident. An employee wound up in hospital in a coma.

A six-cylinder rack containing an argon / hydrogen mixture is dropped from a truck on a national highway, causing a gas leak.A security perimeter was set up. The services of the equipment took care of the cylinders.

In a petrochemical plant, visual inspection detects fumes under the heat insulation of a heat exchanger operating under hydrogen pressure. The first intervention team was mobilized and the unit stopped for depressurization and cooling. A risk analysis was conducted before erecting a scaffold, decalcifying the exchanger and inspecting it under safe conditions. After having defined the fire protection and fire prevention strategy, the operator decided to put the unit back under pressure.