Chemical Reactor Explosion at Medical Imaging Products Plant
(WARNING, UNCLEAR IF H2 WAS INVOLVED)The explosion occurred in a chemical reactor tank of a plant (SEVESO low level) manufacturing products for medical imaging. According to the investigation, the reaction casing the explosion concerned only the gas phase, at the dome of the reactor, consisting of oxygen (due to degassing), and a flammable gas a mixture. The investigation has proposed two alternatives:1. The reaction between di-chloromethane (CH2Cl2) and oxygen stated by a electrostatic charge. 2. Auto detonation of a mixture oxygen and hydrogen produced by the corrosion of a part of the axis of the enamelled stirrer that had been damaged during maintenance. The building was partially blown, especially in the upper part, and fragments (flanges) were found up to several tens of metres away.
Event Date
September 3, 2002
Record Quality Indicator
Region / Country
Event Initiating System
Classification of the Physical Effects
Nature of the Consequences
Causes
Cause Comments
Immediate cause was the formation of flammable gas mixture in the reactor, in presence of oxygen. However, it is not clear of hydrogen was involved.
Facility Information
Application Type
Application
Specific Application Supply Chain Stage
Components Involved
chemical reactor for the production of DICHLORO-DI-CYANOBENZOIQUINONE
Storage/Process Medium
Location Type
Location description
Industrial Area
Pre-event Summary
The event occurred after an atypical reactor behavior that required successive degassing to reduce the pressure.
Lessons Learned
Lessons Learned
Among the corrective actions suggested by the investigations, these were related to the presence of hydrogen:1. To avoid the condition for explosion in the reactor, by setting alarms on oxygen concentration in the gas phase2. To avoid the formation of hydrogen , by ensuring the presence of enamelled protection coating on all the steel surfaces. 3. Control all the possible source static electric discharge. The operator completely changed the process following the accident.
Event Nature
Emergency Action
Unknown
Detonation
No
Deflagration
No
High Pressure Explosion
No
High Voltage Explosion
No
Source Category
References
References
Investigation report of the accident.