Deflagration in Chlorine Electrolysis Cell Due to Blocked Electrolyte Inlet and Faulty Alarm
In a chlorine electrolysis facility, a mixture of oxygen and hydrogen in one of the electrolyzer cells a short-circuit ignited causing a deflagration. The cover of the cell was a thin plastic film which broke as planned. The production was stopped.According to the investigation, the inlet line of the electrolyte in the cell was blocked, which lead to an increase of the temperature in the cell and to the increase of oxygen production. On top of that, the alarm related to temperature control did not function.
Event Date
October 20, 2003
Record Quality Indicator
Region / Country
Event Initiating System
Classification of the Physical Effects
Nature of the Consequences
Causes
Cause Comments
The immediate cause was a malfunction in the cell of a chlorine electrolyzer. Contributing cause was the malfunctioning of the alarm system related to the temperature monitoring of the process.The root cause was probably an underestimation of this hazard in the safety design of the process. Nevertheless, a correct mitigating measure (weak enclosure to reduce the risk of a e deflagration) operated as designed and limited damage,
Facility Information
Application Type
Application
Specific Application Supply Chain Stage
Components Involved
electrolyzer cells
Storage/Process Medium
Location Type
Location description
Industrial Area
Operational Condition
Pre-event Summary
A short circuit ignite a mixture of oxygen and hydrogen in an electrolyzer cell.
Currency
Lessons Learned
Lessons Learned
After the accident, the plant operator put in place a system of monitoring and control of the process performed by on-site teams. This measure was completed later by the installation of an automatic alarm system. Finally, a study was performed to increase the reliability of the whole monitoring system of the installation.
Event Nature
Emergency Action
Unknown
Ignition Source
Detonation
No
Deflagration
No
High Pressure Explosion
No
High Voltage Explosion
No
Source Category
References
References
Event description in the French database ARIA
https://www.aria.developpement-durable.gouv.fr/accident/25777/
(access September 2020)