Most materials stored in silos are affected by high air humidity or moisture regain. Problems include irregular flow, agglomeration, increased microbial activity, chemical reaction with moisture and general degradation of the stored product.
Temperature changes to the silo and moisture laden head space air cause the relative humidity to fluctuate. At lower temperatures the relative humidity of the head space air will increase, often to saturation point (100%RH) when the air begins to deposit moisture on internal surfaces of the silo.
These problems can be eliminated by ensuring that air in the head space is maintained at a low relative humidity. A dry air circulation rate of 1 x silo volume per hour is normally sufficient.
The simplest solution is to install the dehumidifier in the base of the silo skirt.
Dehumidified fresh air is then ducted into the filling line or a separate pipe leading to the head space. This system creates a slight positive pressure which opposes the natural tendency of moisture to diffuse through the silo structure due to differences in vapour pressure.