Distributor plate design

As above for high deformahility systems. In addition, increase compaction forces by increasing bed weight, or altering mixer impeller or fluid-bed distributor plate design. 

Decrease impact velocity to reduce fragmentation Lower-formulation density. Decrease hed-agitation intensity (e.g., mixer impeller speed, fluid-hed excess gas velocity, drum rotation speed). Also strongly influenced hy distributor-plate design in fluid-heds, or impeller and chopper design in mixers. 

The effect of downcomer aeration, of distance between the distributor plate and the draft tube inlet, and of the distributor plate design configuration on solid circulation rate is discussed below. For ease of presentation for materials of different densities, the solid particle velocity in the downcomer rather than the solid circulation rate is used. 

Effect of Distributor Plate Design. Both conical distributor plates of included angles of 60° and 90° were used. They do not seem to affect the solids circulation rate as shown in Fig. 10. Proper location of the distributor plate and the gas nozzle, however, substantially increased the solids circulation rate. 

Figure 10. Comparison of solids circulation rate at different distributor plate design configurations.

Design for Desired Solids Circulation Rate It is assumed that the total gas flow into the bed is known. When the operating fluidizing velocity is selected for the fluidized bed above the draft tube, the diameter of the vessel is determined. The final design decisions include selection of the draft tube diameter, the distributor plate design, the separation between the draft... 

Decrease impact velocity for breakage Decrease excess gas velocity, also distributor plate design may be modified. 

Also strongly influenced by distributor plate design in fluid beds, or impeller and chopper design in mixers... 

Key reactor design issues are catalyst addition point, polymer withdrawal point, distributor plate design, aspect ratio, operating velocity, and temperature control. Temperature uniformity is critical as the reactor operates close to the polymer melting point. Maldistribution can result in polymer sheet formation or bed collapse under severe eonditions, there ean be complete solidilieation of the reactor. 

Experience indicates that a simple theoretical model to predict gas bypassing that takes into account all the design and operating variables cannot be developed. Empirical correlation, however, can be obtained by conducting experiments with tracer gas injection for a given distributor plate design at different operating conditions and at different distances from the draft tube inlet. 

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