Leakage in an ammonia and fertilisers plant

Event

Event ID: 807
Quality: 3
Description: A hydrogen leakage occurred in the ammonia production facility of a plant manufacturing nitrogen products and fertilisers (classified SEVESO high threshold).
It was detected by an operator in charge of safety checks, by the noise and by his portable gas detector. After confirming the leak, the operator stopped the piping (30 bar) to repair it. The ammonia facility was also partially shut down. The operator closed the section at the origin of the leak by installing a threaded and welded plug.
Event Initiating system: Hydrogen system initiating event
Classification of the physical effects: Unignited Hydrogen Release
Nature of the consequences: leak no ignition
Macro-region: Europe
Country: France
Date: 24/07/2018
Component involved: pipe (bend)
Failure mode: rupture, no ignition
Initiating cause: material degradation (external corrosion)
Root CAUSE analysis: The leak was due to corrosion under insulation on a DN50 dead arm: a 90 ° elbow punctured on DN400 piping. The control plan for the piping was not foreseeing the removal of the insulation of this section.
Root causes: System design error
Management factors
Date entry in HIAD: 01/01/2020

Application: Chemical industry
Sub-application: Fertilisers production
Hydrogen supply chain stage: Hydrogen as feedstock
All components affected: ammonia synthesis reactor, hydrogen pipe
Process temperature range [C]: High temperature (100°C to 500°C)
Location type: Confined
Location: industrial area
Operational condition: NORMAL
Pre-event occurrences: A operator was carrying out safety checks in the ammonia workshop.

Number of fatalities: 0
Number of injured persons: 0
Post-event summary: The ammonia workshop was partially shut down.
Official legal action: The Classified Installations Inspectorate requests the RIS (Recognized Inspection Service) to review these plans to check sensitive areas of piping throughout the plant.
Emergency action: After confirming the leak, the operator stopped the piping (30 bar) to repair it. The ammonia workshop was also partially shut down. The operator closed the section at the origin of the leak by installing a threaded and welded plug.

Corrective Measures: The Inspectorate for the Seveso-classified plants requested the RIS (Recognized Inspection Service) to review the inspection plans and to check sensitive areas of piping throughout the plant.