Explosion at a Styrene Plant
Explosion at styrene plant during start-up. A manhead flange failed in a light oil hydrogenation unit releasing 30 kg of hydrogen in a compressor shed. Ignition occurred in 10 to 15 secs. Significant damage to building and structures. Window damage to 365 m. According to the H2TOOLS entry, the investigation team concluded that hydrogen gas was released through a failed 19-inch diameter gasket and ignited under the roof of the compressor shed where it was partially confined. Some gas escaped from the shed prior to the explosion, but it was confined beneath the deck of an adjacent structure and overhead piping. The compressor shed was originally just a roof over the compressors, but over time, walls were added to aid winter operation and maintenance. These walls resulted in confinement of the hydrogen and contributed to the violent explosion.
Event Date
August 20, 1984
Record Quality Indicator
Region / Country
Event Initiating System
Classification of the Physical Effects
Nature of the Consequences
Causes
Cause Comments
The following deficits were identified by the investigation: A major role is plaid by unauthorized modifications played, specifically related to the type of gasket used. The risk assessment did not consider the possibility of a full gasket failure.
Facility Information
Application Type
Application
Specific Application Supply Chain Stage
Components Involved
benzene unit, hydrogen compressor, flange, gasket
Storage/Process Medium
Location Type
Location description
Industrial Area
Operational Condition
Pre-event Summary
PROCESS: styrene manufacturing is based on the alkylation of benzene and ethylene. Ethylbenzene is formed and then dehydrogenated to produce a productstyrene, with by-products: Toluene and hydrogen.
Lessons Learned
Lessons Learned
According to the H2TOOLS entry, these were the actions undertaken aiming at avoiding recurrence:(1) Development of start-up and shutdown procedures checklists (2) design and engineering safety mandatory.(3) Pressure testing at operating mandatory before start-up.(4) Process hazard analysis adopted (5) Gasket material specifications were revised.(6) Separation distance standards developed and implemented.(7) Shatter-resistant windows and doors were installed.(8) Confined space were minimized.(9) A formal modification procedure was instituted (i.e., management of change).(10) Additional combustible gas detectors were installed, with frequent calibration and maintenance required. - Emergency shutoff valves were installed on vessels with critical hydrocarbon inventories.(11) Awareness of chemical processing hazards was increased among all employees through better communication and training.
Event Nature
Emergency Action
Unknown
Release Type
Release Substance
Detonation
No
Deflagration
No
High Pressure Explosion
No
High Voltage Explosion
No
Source Category
References
References
Source lost