Jet Fire of Coke Gas in a Steel industry
The fire took place during maintenance works in one out of the three gas extractors of the coke process line. Main cause was displacement of a flange which allowed the entrance of flammable mixture gas (methane, carbon monoxide hydrogen and benzene) which ignited probably due to electrostatic spark. According to the ARIA report (see references) total quantity of gas released was 62 400 m, consisting of 11,7 t CH4, 0,98 t C6H6, 5,1 t CO and 3,4 t H2.During maintenance works, gas extractors were usually isolated and kept under continuous flow of N2. However, in this case, N2 pressure seemed to be not enough to avoid the entrance of flammable gas.
Event Date
June 6, 2018
Record Quality Indicator
Region / Country
Event Initiating System
Classification of the Physical Effects
Nature of the Consequences
Causes
Cause Comments
Immediate cause was probably the inert gas pressure insufficient to prevent the entrance of the flammable mixture.
Facility Information
Application Type
Application
Specific Application Supply Chain Stage
Components Involved
coke process line, flange
Storage/Process Medium
Location Type
Location description
Industrial Area
Pre-event Summary
The event took place during maintenance of a gas extractor, which has a diameter of 1400 mm. During maintenance, the line was isolated from gas stream using two flanges, one before and another one after the equipment. The accident occurred after maintenance works have finished and the gas extractor was been prepared again for operation: the procedure required as final steps the closing of the downstream flange and then the opening of the inlet one. The leak occurred immediately after the opening of the inlet flange.
Currency
Lessons Learned
Lessons Learned
The operator has foreseen to improve the procedure for the isolation of the section at the following maintenance and to review the risk assessment.
Event Nature
Emergency Action
The employers have been evacuated. The site fire brigade put the extractor under nitrogen and cooled it by water jets. The fire and the leak are stopped after approximately 1 hour.
Release Type
Release Substance
Ignition Source
Detonation
No
Deflagration
No
High Pressure Explosion
No
High Voltage Explosion
No
Flame Type
Source Category
References
References
Event description in the European database eMARS
https://emars.jrc.ec.europa.eu/en/eMARS/accident/view/2c958f15-e9a3-11e…
(accessed September 2020)
609_HIAD_937 company communication.pdf