Explosion at a refinery

An explosion followed by a fire occurred at a refinery, due to the rupture of a hydrogen line inside a hydrogen heater.
Since the refinery control room noticed something wrong with the equipment’s readings, an employee was sent to check on the hydrogen heater. Sometime its arrival on location, the explosion occurred.
The reason for the release remained unknown.

unknown

DESCRIPTION OF THE PROCESSES
The ' hydrogen heater' affectted by the incident was probably the fired heater used to pre-heat the feedstock to a refinery process such as a hydron-cracker or hydro-desuplphurisation unit (see for example HIAD_656).

One injured worker sustained second and third degree burns to his back and face.
The hydrogen heater suffered heavy structural damage
No off-site impact.

Large water cannons, permanently mounted throughout the sprawling facility, were used to cool the hydrogen heater. Officials also injected nitrogen into the line to purge the remaining hydrogen and allowed it to burn off.

Rupture of hydrogen or process gases tubes in pre-heaters /heat-exchangers / fired heaters is a recurrent event up to recent times. This is not surprising, considering the high temperatures and pressures involved. The most common causes are materials degradations due to manufacturing defects and operative stresses. Ruptures tend to happen during operative transients, which may cause over-heating due to reduction of flows. When the releases occur also in presence of naked flames, as in fired heaters, which use conventional fuels burners, ignition and explosion in the confined of the heater box is ensured. Nevertheless, due to sturdy heater constructions, it rarely happens that damage extends to the outside environment.