| Abstrakt: |
We analyzed modified spouted bed configurations incorporating three different types of mechanical stirrer, in comparison to a conventional spouted bed. Straight-blade, inclined-blade, and helical screw agitators were used with different types of inert particles. The behavior of the fluid dynamic curves was qualitatively similar for the systems with agitators and the conventional design, except for the screw-type agitator. For the straight-blade and inclined-blade agitators, increase of the rotation speed had a positive effect on the fluid dynamic parameters, reducing the air flow and the pressure drop in the bed. The effects of rotation speed and blade inclination on the fluid dynamics were minimized at 240 rpm, although the mass of particles could influence these parameters. The inclined-blade stirrer performed the best, reducing airflow between 40 and 66% compared to the conventional spouted bed. For the screw-type stirrer, the reduction was around 27% in some of the experiments. The rotation speed of the stirrer and the air flow to agitate the bed affect the average cycle time of the process, with a stronger effect on the rotation speed. Overall, the use of the stirrers in the bed provided significant improvement, with reduction of both the air flow, the pressure drop and average cycle time, as well as greater stability of the bed. [ABSTRACT FROM AUTHOR] |
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