Fire in a in a fertiliser manufacturing plant

The incident took place on the reforming furnace unit of the plant. Around 23:30 pm, during a normal inspection tour, an operator detected a fire on a section of a steam line.
The operator immediately informed the control room. The unit was reduced in speed, with process parameters monitored to ensure that the situation did not worsen. Steam hoses were used in the direction of the flame and the identified hot spots. The next morning at around 6:00 am, the unit was progressively shut down and the fire extinguished.

The fire occurred in one of the boxes containing the header of on one of the reforming tubes bundle. The fire did not have impact on the surrounding area or equipment.

An investigation of the causes, carried out after the removal of the affected vessel, showed a leak on a weakened flange. The gasket was intact, no trace of leakage was detected.
Therefore The INITIATING CAUSE was a leaking flange which had partially loosened, possibly due to differential thermal dilatation.

reformer unit, gasket

DESCRIPTION IOF THE REFORMING UNIT
The reforming furnace unit consisted of 198 tubes containing a catalyst. Each furnace contained 11 headers on which 18 reforming tubes were welded. Each header was enclosed in a box and fed the transfer line to the secondary reforming.

The operator reduced the flow of the unit and monitored the process parameters to ensure that the situation was not worsening. Steam hoses were used in the direction of the flame and the identified hot spots. Approximately 7 hours alter the unit was progressively shut down and the fire extinguished.