Event
- Event ID
- 841
- Quality
- Description
A leak of hydrogen and hydrocarbons ignited at the seal located between the bottom and the body of a heat exchanger of a desulphurization unit of a refinery.
The fire was 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 was delayed by the malfunction of an automated system. Nevertheless, when finally successful, it allowed the fire to be brought under controlled. It was extinguished following the emptying of the reactor located upstream (in the morning of the following day).
The emergency intervention was provided by the emergency services of the plant, 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.- Event Initiating system
- Classification of the physical effects
- Hydrogen Release and Ignition
- Nature of the consequences
- fire
- Macro-region
- Europe
- Country
- France
- Date
- Component involved
- heat exchanger (flange)
- Failure mode
- rupture & ignition
- Initiating cause
- wrong installation
- Root CAUSE analysis
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.- Root causes
- Date entry in HIAD
- 01/01/2020
Facility
- Application
- Petrochemical industry
- Sub-application
- Hydrodesulphurisation process
- Hydrogen supply chain stage
- All components affected
heat exchanger of a desulphurization unit, refinery
- Process temperature range [C]
- High temperature (100°C to 500°C)
- Process pressure range [MPa]
- medium to high pressure (10 to 50 MPa)
- Location type
- Open
- Location
- industrial area
- Operational condition
Emergency & Consequences
- Number of fatalities
- 0
- Number of injured persons
- 0
- Post-event summary
The unit was restarted only 4 weeks later.
- Emergency action
17:30 Fire at the seal of the heat exchanger. The emergency plan is initiated.
The fire is alimented by the leak under pressure for about twenty minutes causing the emission of a plume of black smoke.
02:00 (morning) Fire extinguished after decompressing the unit and emptying the reactor located upstream.
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 collected firewater is directed directly to the treatment plant.
20:22. (evening of the day after) The emergency plan is terminated. The collected firewater is directed directly to the treatment plant.
In-depth data
- Release type
- gas mixture
- Involved substances (% vol)
- H2
hydrocarbons - Probable IGNITION SOURCE
References
- Sources categories
- ARIA
- Reference & weblink
ARIA data base event no. 32145
https://www.aria.developpement-durable.gouv.fr/accident/32145/
(accessed March 2026)
