Event
- Event ID
- 901
- Quality
- Description
The accident occurred on one of the heat exchangers of the hydrodesulphurisation unit.
The role of the exchanger , located between the charge pumps and the furnace, was to heat the charge using the hot products from the reactor. Before the exchanger, pressurised hydrogen is injected into the charge. The exchanger was equipped with interchangeable bundles mounted with deflector plates.During a shutdown, some beams were mistakenly reassembled upside down. When the installation restarted and the compressor of the hydrogen circuit arrived at 75% of its capacity, one of the deflectors was blown off and obstructed the inlet of the exchanger. Consequently, the safety device of the compressor triggered the compressor stop and the pressure release valves released part of the contents.
- Event Initiating system
- Classification of the physical effects
- Unignited Hydrogen Release
- Nature of the consequences
- leak no ignition
- Macro-region
- Europe
- Country
- France
- Date
- Component involved
- heat exchanger (pipe)
- Failure mode
- rupture, no ignition
- Initiating cause
- wrong installation
- Root CAUSE analysis
The reason for the over-pressurisation of the compressor and the pressure relief activation was the block of part of the gas flow into the heat exchanger tubes bundle.
A ROOT CAUSE component was a human error occurred when re-installing the exchanger's components inverted. However, an additional factor was the failure of the supervision and final inspection procedure to detect the mistake.
- Root causes
- Date entry in HIAD
- 01/01/2018
Facility
- Application
- Petrochemical industry
- Sub-application
- Hydrodesulphurisation process
- Hydrogen supply chain stage
- All components affected
heat exchanger
- 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
- Pre-event occurrences
The desulphurisation unit was restarted after a shutdown during which component of the heat exchanger unit were (wrongly) reinstalled
Emergency & Consequences
- Number of fatalities
- 0
- Number of injured persons
- 0
- Post-event summary
Part of the hydrocarbon load, including hydrogen, was released to the environment.
In-depth data
- Release type
- gas mixture
- Involved substances (% vol)
- H2,
hydrocarbons - Probable IGNITION SOURCE
References
- Sources categories
- ARIA
- Reference & weblink
Original description of the event in database ARIA
