Agglomeration-free drying
The NARA Media Slurry Dryer is designed for drying slurry materials continuously and obtaining powders without causing agglomeration, in a size of primary particles.
The slurry is pumped into the dryer. Inside the dryer there is layer of ceramic balls (Aluminium oxide) fluidized by hot air. The slurry becomes distributed on the surface of the balls due to the movement of the balls, induced by the air flow. The ceramic balls have a huge surface area, so that the liquid forms a thin film around them. The huge surface prevents the dispersed particles to touch each other. The hot air evaporates the liquid and the particles peel
off the surface by the movement of the ceramic balls and the air flow. The moist air is then separated from the particles by a cyclone or bag filter.
The collected particles are dried and have not agglomerated, because when they were in the process of drying, they did not touch each other.
| Dispersion + Adhesion | Drying + Cracking | Peeling + Discharging |
| Slurry is supplied directly into fluidized media particles by pump and will be dispersed as adhering to the media surfaces in a thin film form. | As the dispersed slurry in the tower contacts to the hot air effectively, evaporation and drying will be carried out in a short time. | Solids remaining on the surface of media particles are peeled off from the surface by the friction of each media particle and discharged out of the tower entraining in the exhaust gas and collected as dried product at collecting equipment. |
- Active movement of the media can disperse slurry material into the fluidized bed readily and efficiently.
Therefore, a wide range of materials with low or high viscosity can be dried. - Heat transfer capability coefficient ha[KW/m3K] is similar to the Fluidized Bed Dryer (FBD). Compared with a spray dryer, the volume of the drying tower is approximately 1/20.
- Active fluidization of the media causes efficient heat exchange and lowers the necessary heat energy.
- For atomization of the slurry material a spray device is not necessary. Therefore, adjustments of the viscosity of the slurry are not required.
- Easy maintenance due to no rotating equipment and driving parts inside the drying tower.
- A version for the food and pharmaceutical sectors is also available.
| Material | Volatile component | Moisture raw material [%WB] | Particle diameter raw material [µm] | Hot air exhaust gas temperature [°C] | Dried products capacity [kg/h • m²] |
| Ceramics | Water | 70 / 0.2 | 0.7 / 0.6 | 250 / 90 | 300 |
| Barium sulfate | Water | 40 / 0.1 | 1.9 / 1.7 | 150 / 65 | 750 |
| Ferrite | Water | 60 / 0.2 | 32 / 26 | 300 / 100 | 620 |
| Barium titanate | Water | 50 / 0.1 | 1.3 / 1.1 | 200 / 90 | 510 |
| Polystyrene resin | Methanol | 75 / 1.5 | 1.3 / 1.5 | 85 / 55 | 160 |
| Glas powder | Ethanol | 50 / 1.0 | 2.1 / 2.1 | 150 / 80 | 900 |
| Ferrite | Toluene | 50 / 0.8 | 7.3 / 7.6 | 150 / 90 | 450 |