Event
- Event ID
- 301
- Quality
- Description
An explosion occurred in an electrostatic precipitator whilst it was being accessed for maintenance.
The explosion caused an inspection hatch cover, which had been unbolted, to be blown off and created a fireball which engulfed an electrician causing minor injuries.The sequencing of the shutdown tasks was fundamentally flawed as the spades were introduced immediately prior to the opening up of the vessel, after the 1.5 day steam purge and 3.5h cooling period.
Leakage past the inlet gate valves would allow a flammable atmosphere to develop as the main constituents of coke oven gas are hydrogen, methane, carbon monoxide etc.
The exact source of ignition cannot be established, the probable source was pyrophoric deposits in the vessel.- Event Initiating system
- Classification of the physical effects
- Hydrogen Release and Ignition
- Nature of the consequences
- Macro-region
- Europe
- Country
- United Kingdom
- Date
- Component involved
- reactor / oven / furnace / test chamber
- Failure mode
- internal explosion
- Initiating cause
- accidental hydrogen entrance
- Root CAUSE analysis
INITIATING cause: probably leakage of the combustible gas mixture (hydrogen, methane, carbon monoxide) ignited by pyrophoric deposits.
ROOT cause: mistakes in the maintenance procedure, specifically lack of gas detection step.- Root causes
- Date entry in HIAD
- 28/02/2009
Facility
- Application
- Steel and metals industry
- Sub-application
- generic metal processing
- Hydrogen supply chain stage
- All components affected
Electrostatic precipitator of a coking plant
- Location type
- Confined
- Location
- industrial area
- Operational condition
- Pre-event occurrences
The facility was under maintenance.
Emergency & Consequences
- Number of fatalities
- 0
- Number of injured persons
- 1
In-depth data
- Release type
- gas mixture
- Involved substances (% vol)
- H2, CH4, CO
- Probable IGNITION SOURCE
- Explosion type
- Detonation
References
- Sources categories
- HSE
- Reference & weblink
Event description provided by HSE, original source confidential
