Particle size dependence feed flow velocity

The optimum conditions needed to achieve the desired sulfur capture efficiency (90 percent) is dependent on sorbent type, coal type, and fluidized bed design. Representative conditions are a bed temperature of 1116 K, a sorbent particle of 1 mm, and a Ca/S ratio of about 3. The bed temperature selection is based on the admittedly shaky evidence that this is where the maximum sulfation peaks. The particle size selection is a compromise between a desire to use high gas velocities and the observed decrease in sulfation with increasing size (Figure 2). The Ca/S ratio corresponds to a maximum sulfation of about 0.3. For these conditions the mass feed rate of a limestone sorbent is 0.345 that of the coal feed and the flow rate of the partially sulfated spent sorbent is 0.285 the coal feed rate. 

Freely flowing particulate matter sliding down a vertical chute assumes a flow profile similar to a turbulent velocity distribution. Due to wall and interparticle friction there is a velocity gradient in a material layer close to the chute walls (Figure 288a). The thickness of this layer depends on particle size and cohesiveness of the material (stickiness). When the feed approaches the gripping... 

Unlike a solids collecting cyclone, the performance of a demisting cyclone is much more dependent upon the flow conditions that exist in the upstream piping. This, of course, is because the particle or drop size distribution feeding the cyclone is strongly dependent upon such factors as shear rate and surface tension. The shear rate is, itself, a function of the upstream pipe diameter, the superficial gas velocity and the physical properties (namely densities and viscosities) of the gas and liquid phases. 

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