July 26, 2018
Purpose: To explain how to reduce coal dust in coal-fired power plants.
Highlights:
- What causes most coal-fired power plant explosions?
- What causes the heat source in a plant fire?
- How do you reduce coal dust?
- How to create an adequate housekeeping plan.
Between 1980 and 2005, coal-fired power plants saw an average of 11 fires/explosions, 29 injuries, and 5 deaths each year.
Coal is as volatile as always.
Just last year, the India Coal Plant exploded and killed 43 people. Dozens more were injured when gas and steam were released. The explosion was due to excess ash that caused the pressure in the boiler unit to quickly reach 70 times its normal level in just minutes.
What is the main cause of coal-fired power plants?
When a fire ignites, oxygen, fuel, and heat have merged into the fire triangle. When an explosion happens, the fire triangle is present as well as the dispersion of confined dust. While fuel (coal) and oxygen cannot be avoided in a coal-fired power plant, there is a way to avoid an ignition source and mitigate dust.
What causes a heat source in coal-fired power plants?
The main cause of heat is friction.
When a conveyor belt collects coal dust, it becomes a fire hazard. Coal dust only needs to accumulate to a footprint size and already it is a fire hazard. As the conveyor moves, any friction that occurs can be enough of a heat source to cause an explosion.
Any machine that is not running impeccably can cause friction and, as a result, a heat source.
Other causes of heat sources are
- Friction through mixing operations
- Electrical shorts
- Tools
- Storage bins moving
As you can see, creating a heat source is easier than one would think.
How do you reduce coal-fired power plant hazards?
There are several ways to reduce the amount of coal dust in a coal-fired power plant. But the main solution is housekeeping.
A solid housekeeping routine should be developed to reduce the chances of an explosion.
What makes a good housekeeping routine?
- Document your housekeeping schedule.
- Ensure the dust collector is well-maintained.
- Wet the dust to weigh it down with a wash down system.
- Thoroughly clean bunkers, silos, and conveyors of dust before an outage.
- If needed, pump carbon dioxide into sealed bunkers or silos to remove oxygen.
Conclusion
Coal dust can be detrimental to your coal-fired power plant. By mitigating the coal dust through proper housekeeping and equipment, you greatly reduce your chances of having an explosion at your plant.