New Dual Feed dryers from GEA Niro

Pigment & Resin Technology

ISSN: 0369-9420

Article publication date: 22 March 2011

84

Citation

(2011), "New Dual Feed dryers from GEA Niro", Pigment & Resin Technology, Vol. 40 No. 2. https://doi.org/10.1108/prt.2011.12940bad.004

Publisher

:

Emerald Group Publishing Limited

Copyright © 2011, Emerald Group Publishing Limited


New Dual Feed dryers from GEA Niro

Article Type: New products From: Pigment & Resin Technology, Volume 40, Issue 2

GEA Niro has developed a new Dual Feed System (patent pending) for its SWIRL FLUIDIZER™ dryers. The innovative new system allows very low viscosity and thixotropic feeds to be dried to produce a powder with consistent moisture content and product quality. The system has been successful in drying products such as silica and titanium dioxide and products where the filter cake is thixotropic, becoming liquid under mechanical stress.

In the past, it has been impossible to dry some products on flash dryers like the SWIRL FLUIDIZER™ because either their solid content or viscosity was too low. The problem has previously been solved by mixing dry powder into the liquid feed product in the feed tank to increase the solids content and/or viscosity before it is fed into the drying chamber. This requires a difficult and power-consuming mixing process that can produce a feed with an inconsistent moisture content. This inconsistency often results in unstable operation of the dryer and large variations in the final powder’s moisture content.

The Dual Feed System uses the mixing that already takes place in the drying chamber, driven by its rotating disintegrator. One feed carries the liquid feed product to the drying chamber; the second carries dry powder pneumatically or by a screw feeder. The two inlet streams are arranged in such a way that the dry powder is immediately mixed with the liquid feed so that the moisture is distributed over the entire available powder surface. The enlarged, moist surface ensures a rapid evaporation of the liquid inside the drying chamber.

The advantage of the system is that the liquid feed-rate can be controlled very accurately by adjusting the pump speed. This means that the evaporation load of the dryer can be kept consistent which results in a stable operation. Furthermore, there is no need for additional mixing equipment.

In some cases, the addition of dry powder has been limited to the start-up sequence of the dryer, allowing stable conditions to be achieved more quickly.

The Dual Feed System is available for new SWIRL FLUIDIZER™ units and for retrofitting to existing units.

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