Powder handling and storage is supplied by GEA Colby, a member of the GEA Group. GEA Colby supplies different types of conveying systems, depending on:
- type of product – agglomerated or non-agglomerated
- conveying distance – horizontal and vertical
- number of silos – vacuum or pressure systems
All flowsheet animations are available in the GEA Niro download area.
Powder handling from spray drying plants
When powder is discharged from a spray drying plant, it is typically stored in 25 kg bags or in Big Bags. The Big Bags (1-2 m3) are typically filled directly from the dryer and then stored. If the powder has to be filled into 25 kg bags, intermediate storage in powder silos is normally used. This makes it possible for the dryer to operate 20-24 h/day with only 1 or 2 bagging-off line shifts.
The number of silos depends on the required storage capacity. From the storage silos, the powder is typically conveyed to an intermediate hopper above the bagging-off line where exchange of atmospheric air with an inert gas may be required to achieve extended shelf life. On top of this intermediate hopper, a number of smaller vacuum chambers can be placed. They are filled with powder – one by one. Then the air is evacuated and replaced by N2
before the pre-gassed powder is discharged into the intermediate hopper and the vacuum chamber is ready for a new load of powder. Pregassing to 1 % oxygen or lower can be achieved in this hopper.