Active Dust Control

Dust collection systems, as applied to bulk material handling systems should be referred to as “excess air collection systems”. In the case of coal dust, the dust is a viable fuel for the boiler, if it can be safely conveyed there for combustion. Collecting the dust from the conveyance stream only adds additional operational costs. Coal dust should be maintained on the conveyors and loaded safely into the silos or bunkers.

Dust collection systems should be used to remove excess air from transfer systems. This excess air is typically a function of induced, entrained, displaced or generated air movement. Excess air should be minimized through passive means, as discussed in this article, with the resultant air collected at the proper face velocity to minimize the amount of material removed from the conveyance stream. This design approach utilizes the filter media to protect the environment from fugitive dust release.

It is important to not design a closed loop dust collection/return system, wherein combustible dust is constantly re-ingested into the collection system, raising the grain loading over the run cycle and subsequently over-stressing the collector beyond its design point.

All dust collection systems serving combustible dust materials shall conform to the latest code for fire protection and explosion isolation and venting.

Dust suppression systems can be employed to provide a typically lower initial investment solution to dusting problems. The ongoing cost of chemical and equipment upkeep may offset this advantage when projected over the life of the control system. When another combustible dust control infrastructure is not already in place, dust suppression may be a good financial choice. Unlike coal dust collectors, risk is not concentrated in one place, nor is any dust removed from the conveyance stream.

Dust suppression still requires passive dust control to be most effective. If induced air flow is able to motivate dust off of the material stream, dust suppression may be rendered ineffective. If engineered containment structures are not in place, dust suppression may not have the proper time to interact with the coal stream and maximize its effectiveness.