Explosion and Fire in a Fertilizer Production Plant
The syngas leak (hydrogen + methane) occurred at exit of the ammonia production reactor and led to an explosion followed by a fire.The start point of the sequence of events was the syngas at the reactor outlet reaching an abnormal pressure of 150 bar and a temperature of 300C. This caused a flange seal to move, causing the gases to leak. The accident caused a pressure waves and fire observed on the installations over a distance of 450 metres.
Event Date
July 24, 2010
Record Quality Indicator
Region / Country
Event Initiating System
Classification of the Physical Effects
Nature of the Consequences
Cause Comments
The immediate cause is unknown: the ARIA report does not mention the reason(s) for the unexpectedly high pressure/temperature values. From the corrective actions adopted it may be assumed the absence of a risk assessment considering the possibility of ignition of flammable gases at the ammonia reactor, and the usage of a inadequate components (flange). Both items point at a risk management root cause.
Facility Information
Application Type
Application
Specific Application Supply Chain Stage
Components Involved
ammonia reactor
Storage/Process Medium
Location Type
Location description
Industrial Area
Pre-event Summary
The pipe diameter at the exit of the ammonia reactor had a diameter of 300 mm (DN300). The flange used on this pipe was a model with a lenticular seal between the clamp and the tube, screwed to the flange by bolts.
Currency
Property Loss (onsite)
2500000
Lessons Learned
Lessons Learned
After the accident, the operator considered the following measures:1) to conduct an explosion risk study in areas where ammonia or flammable gases are handled and in areas where an explosion has already occurred;2) the installation of an personnel alert system and an evacuation procedure in the event of a process failure that could lead to an explosion;3) the replacement of the flanges by a model more adapted to over-pressure hazard.
Event Nature
Emergency Action
Unknown
Detonation
No
Deflagration
No
High Pressure Explosion
No
High Voltage Explosion
No
Source Category
References
References
Event description in the French database ARIA
https://www.aria.developpement-durable.gouv.fr/accident/50265/
(accessed October 2020)