EXPERIMENTAL INVESTIGATION OF A ROTATING FLUIDIZED BED IN A STATIC GEOMETRY
Advancing the chemical engineering fundamentals
Particulate Systems (T2-3P)
Keywords: Rotating fluidized bed, Fluidization, Centrifugal force, Fluidized bed
The new concept of a rotating fluidized bed in a static geometry (RFB-SG) (1) is experimentally investigated. The rotating motion of the particle bed and the tangential fluidization of the solids are obtained by the tangential injection of the fluidization gas via multiple gas inlet slots in the outer cylindrical wall of the fluidization chamber. The solids experience a radially outwards centrifugal force. The gas, on the other hand, is forced to move radially inwards towards a chimney with one or more outlet slots, creating a radially inwards gas-solid drag force and fluidizing the solids radially.
For the experimental investigation of the new fluidization concept, one and the same non-optimized fluidization chamber design is used with either large diameter, low density polymer particles or small diameter, higher density Alumina particles. The fluidization chamber is operated in continuous mode, at different solids loadings and in the vertical and horizontal position.
In all cases, a rotating fluidized bed and a reasonable to good gas-solid separation can be obtained, provided that the solids loading and the particle bed rotational speed are sufficiently high. The latter requires a sufficiently high gas flow rate. The behavior of the rotating fluidized bed is, however, very different with the polymer and the Alumina particles, in particular at higher solids loadings. Whereas the polymer particles tend to form a dense uniform bed, the Alumina particles tend to form a less dense and less uniform bed. With the current non-optimized fluidization chamber design, the radial fluidization is minimal with the polymer particles, but quite pronounced with the Alumina particles. Bubble formation is observed with the Alumina particles. Bubbles originating at the gas inlets are transported tangentially and radially or mainly tangentially, depending on the solids loading. Solids losses via the chimney are negligible with the polymer particles, but somewhat more pronounced with the Alumina particles as a result of the radial expansion, the bubble formation, and some recirculation near the chimney immediately downstream of the chimney outlet. An optimization of the fluidization chamber design and the operating conditions is necessary for each given type of particles.
(1) de Broqueville Axel : Catalytic polymerization process in a vertical rotating fluidized bed : Belgian Patent 2004/0186, Internat. Classif. : B01J C08F B01F; publication number : 1015976A3
Presented Monday 17, 13:30 to 15:00, in session Particulate Systems (T2-3P).
