Hydrogen & hydrocarbon fire in the desulphurization unit of a refinery

The leak ignited at the seal located between the bottom and the body of a heat exchanger of a desulphurization 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).
The intervention is provided by the emergency services of the operator without recourse to the firefighters of the municipality put however on preventive alert.
The affected unit was stopped, repaired and restarted only 4 weeks later.
The analysis of the causes performed by the operator reveals a failure of the mounted seal, different from the seal recommended at this point, poorly positioned and tightened non-homogeneously.

The INITIATING CAUSE of the release was the failure of the seal.
The ROOT CAUSE was a mistake when mounting the seal, which was different from the recommended seal, poorly positioned and tightened non-homogeneously.

heat exchanger of a desulphurization unit, refinery

The unit was restarted only 4 weeks later.