Is your product a liquid solution or slurry? Is it non heat sensitive? And do you want to produce a dense granulated and free flowing product? Then spray fluidizing is the technology to use.
What is spray fluidizing?
- Is it spray drying? Yes, as the liquid product is sprayed into a spray fluidizing chamber where a part of the solvent is evaporated using the exhaust air from the fluid bed dryer in a counter current flow.
- Is it fluid bed drying? Yes, as the remaining solvent is evaporated and the product is finally cooled in a combined back mix and plug flow fluid bed. It is all combined in one unit.
The SPRAY FLUIDIZER™ is the result of GEA Niro's group of highly educated process engineers and product technologists working in our comprehensive modeling and testing facilities with more than 75 pilot plants available worldwide - also for our customers. The development was a new SPRAY FLUIDIZER™ generation with improved ability to continuously build up a dust-free, free-flowing, high density product with compact granulates involving solidification of solids from liquid feed as solutions or slurries. It has especially proved efficient for CaCl2, MgCl2 and Na-Benzonates.
The spray fluidizing process
The spray fluidizing process is continuous. The liquid feed is sprayed into the back mix section of the fluid bed by means of nozzles. Counter-currently, the spray particles are partially dried as they meet warm and relatively dry exhaust air from the fluid bed on their way to the fluidized powder layer in the fluid bed. Here, the desired mechanism of particle growth by layering and simultaneous drying on the surfaces of the smaller granules and nuclei particles takes place. The operational conditions control the granule growth and structure. The mean particle size is typical from 0.3 – 0.5 to 2.0 mm. The dryer can have special features around the plate for distributing the drying air, recycling of fines, and nozzle position.
To improve thermal efficiency, internal submerged heating panels can be applied in the drying section of the fluid bed. Warm water or steam is recycled in the heating panels reducing the amount of drying air and the size of the plant and thereby also the building.
Depending on local authorities and their requirements for the exhaust air, the cyclone can be replaced by a bag filter. The fines from the dust collector are returned to the process together with the fines and milled oversize from the sifter. Only first grade products that fit your specifications leave the SPRAY FLUIDIZER™.
GEA Niro's SPRAY FLUIDIZER™ is a very flexible and cost efficient solution with regards to both investment and operation. It is designed to meet the requirements of our customers and their local authorities and as such it is available in:
- Open, environmentally friendly plants with effective bag filters ensuring emission of clean exhaust process air
- Semi closed plants utilizing low oxygen combustion gas as process air
- Semi closed plants, self-inertised and featuring incineration of the exhaust air
- A closed cycle concept with nitrogen purged process gas circuit