An Explosion on a Hydrogenation Reactor of a Pharmaceutical Products Plant
The explosion occurred while starting up for the first time a hydrogenation reactor.The reactor was being commissioned, by performing tightness tests under hydrogen atmosphere at very high pressure. The rupture of one of the seals caused a hydrogen release followed by the auto ignition of a 30 liter air/hydrogen mixture. Five employees were injured. Material damage was confined to the immediate perimeter of the reactor. The hydrogen detectors controlling the closing of the H2 supply valve had not yet been installed. Nevertheless, their absence was not critical thanks to the prompt reaction taken by employees. The preliminary tests carried out under nitrogen were insufficient.
Event Date
October 31, 1995
Record Quality Indicator
Region / Country
Event Initiating System
Classification of the Physical Effects
Nature of the Consequences
Causes (Select all applicable options):
Cause Comments
The immediate cause was the failing of a seal under hydrogen pressure during a tightness test. The root cause was the ill-designed or ill-performed commissioning procedure. The previous tightness under nitrogen were performed or designed in a way that did not identify the release event which occurred under hydrogen. The cause classification could be operation or design.
Application Type
Application
Specific Application Supply Chain Stage
Components Involved
Hydrogenation reactor, seals
Storage/Process Medium
Location Type
Location description
Industrial Area
Operational Condition
Pre-event Summary
The reactor had been installed of the first time, and the incident occurred during the commissioning tests.
Lessons Learned
As a rule, tightness tests have to performed with non-flammable gas, but have as well to consider the difference in behavior between the gases. Helium could be a better replacement for hydrogen than nitrogen, it is however more expensive.
Emergency Action
The hydrogen detectors controlling the closing of the H2 supply valve had not yet been installed. Nevertheless, their absence was not critical thanks to the prompt reaction taken by employees.
Release Type
Release Substance
Hydrogen Release Concentration (%)
100.00
Release Amount (kg)
30.00
Detonation
No
Deflagration
No
High Pressure Explosion
No
High Voltage Explosion
No
Source Category
References
Event description in the French database ARIA
https://www.aria.developpement-durable.gouv.fr/accident/7518
(accessed October 2020)