In various industrial settings, such as coal grinding in cement plants, the risk of fires and explosions is ever-present. To mitigate these dangers, emergency inertisation is employed as a safety measure. This process involves introducing an inert gas into an enclosed potentially explosive environment to displace oxygen, thereby inhibiting the explosive combustion of flammable materials.
The Principles of Inertisation
Inertisation is based on the fundamental principle of explosion prevention: eliminating one of the three elements required for explosive combustion—heat, fuel, and an oxidizer (typically oxygen). By introducing an inert gas, such as CO₂ (carbon dioxide) or N₂ (nitrogen), into an enclosed environment, the oxygen concentration is reduced to levels insufficient to support explosive combustion.
The Process of Emergency Inertisation
Implementing emergency inertisation involves several critical steps:
- Detection: Advanced sensors and monitoring systems continuously measure temperature and CO-in-air concentrations, detecting intensified oxidation of combustible material in the system.
- Activation: Upon detection of a hazardous condition, the inertisation system is automatically or manually activated, triggering the release of inert gas into the affected area.
- Displacement: The inert gas displaces oxygen, reducing its concentration below the threshold needed for combustion.
- Maintenance: The inert atmosphere is maintained until the hazard is mitigated, ensuring that any residual risks are managed effectively.
How does it work?
Emergency inertisation’s main aim is the prevention of explosive combustion.
Once the injection of the gaseous inerting medium has reduced the O₂-in-air percentage to a value below 12 % explosive combustion of coal dust-in-air is no longer possible. It makes sense to monitor the progress of the inertisation by continuous O₂ measuring.
Once the reduction of O₂ to a percentage below 12 % is achieved, further reduction of the O₂ percentage by continuation of the medium injection eventually can extinguish ongoing intensified oxidation of the combustible material.
It is essential that no gaseous inerting medium is lost to the atmosphere.
Remark
When purchasing an emergency inerting system it is essential that the system’s design is for the purpose described here. Unfortunately, many suppliers don’t get this right.