Defluidized zones

C.L. Briens, S. Barghi, Defluidized zones in liquid-solid fluidized beds, Powder Technol. 114 (2001) 186. 

A number of experimental measurement techniques are discussed, with a focus on noninvasive optical techniques such as particle image velocimetry and digital image analysis, as well as a number of academic numerical modeling tools such as discrete particle model and two-fluid model. Not only hydrodynamic aspects, such as the emergence of defluidized zones and solids circulation profile inversion, but also the effect on the bubble size distributions are discussed for wall-mounted membranes and horizontally immersed membranes. 

Figure 16.7 The operability map of PP pyrolysis at 450°C, showing the zone of stable fluidization and that of defluidization. Vq, is the particle collisional velocity, which can be evaluated as reported in [37]. (Reproduced by permission of AlCHE)...

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