Explosion in an ammonia plant

Event

Event ID: 194
Quality: 3
Description: A release of a mixture of hydrogen, nitrogen and ammonia ignited and exploded in the ammonia synthesis unit. The release was due to a cracked pipe near a flange located at the top of the gas-gas heat exchanger.
The leak immediately ignited, resulting in a powerful explosion followed by a fire, brought under control in less than a hour.
The gas mix consisted in 69% of hydrogen, 23% of nitrogen and 8% of ammonia.
Event Initiating system: Hydrogen System Initiating Event
Classification of the physical effects: Hydrogen Release and Ignition
Nature of the consequences: Explosion Followed By A Fire
Macro-region: Europe
Country: France
Date: 14/09/2000
Main component involved?: Pipe
How was it involved?: Rupture & Formation Of A Flammable H2-Hc-Air Mixture
Initiating cause: Unknown
Root causes: Unknown (No additional details provided)
Root CAUSE analysis: The INITIATING CAUSE was the release of process gas due to a crack on a pipe connected to a heat exchanger.

The ROOT CAUSE is unknown.

Application: Chemical Industry
Sub-application: Fertilisers production
Hydrogen supply chain stage: Hydrogen As Feedstock
All components affected: flange, pipe, heat exxhanger
Location type: Open
Operational condition: Unknown (No additional details provided)
Description of the facility/unit/process/substances: From the provided data: 30C, 300 bar and %vol., a total mass of 130 kg can be calculated, out of wich 14 kg of H2

Number of injured persons: 0
Number of fatalities: 0
Environmental damage: 0
Currency: Euros
Property loss (onsite): 1300000
Property loss (offsite): 0
Post-event summary: The material damage was assessed between the 3 and the 8 millions of French Francs.
The plant was stopped for 5 weeks.