Dry Fog has been used specifically for a variety of moisture sensitive materials such as Clay, Nitrates, Limestone, Clinker, and even Cement. We evaluate site-specific conditions to determine Dry fog applicability with some of these materials. Typically, with moisture sensitive materials, Dry Fog works better on large open areas such as ship holds & dump pockets than it does with enclosed conveyor belts where it is possible for agglomerated material to build up and harden.
There are several issues with using Dry Fog at Stack Out Conveyor Discharge Points. Generally, there are three sources of dust generation: (1) separation of the fines coming off of the belt, (2) separation of the fines as the material freefalls and (3) the impact of the material onto the storage pile. In some cases, the discharge chute can be enclosed with Strip Curtains and positioned close to the pile. In other cases, water sprays must be added at the tail of the conveyor to pre-moisten the material before it stacks out. Typically, we can indicate to our customer's the feasibility of using Dry Fog at Stack Out Conveyors given drawings and photographs. DustTamer Wind Fence Systems are another control measure we use for storage piles.
Dry Fog has the lowest BTU Penalty (chart source Martin Engineering) of any dust suppression system by far. Power Plant Operators report that they have not been able to detect any perceivable increase in moisture to the coal.
Dry Fog systems operate between 7 and 15 pounds water pressure. We typically ask for a source that maintains around 50 PSI water pressure.
In addition to our standard two-stage filtration for water and compressed air, the nozzle design itself has many features to prevent plugging: