Cyclone Separation Efficiency

Figure 14-19. Cyclone separator efficiency curve. (Adapted from reference 4. Courtesy of VDI-Verlag, Dusseldorf, Germany.)...

In the previous chapter we have examined various models for predicting the velocity distributions in cyclones. In this chapter we wish to first present a brief discussion of the issues, and to then present some of the literature models available for computing cyclone separation efficiency. 

There are basically two modeling concepts for cyclone separation efficiency in the literature the equilibrium-orbit models and time-of-ffight models. 

Table 5.4.1. Models for cyclone separation efficiency at low solids loadings...

Both the models of Smolik and Zenz predict cyclone separation efficiency as a function of loading purely from knowledge of the efficiency at low loading and the loading itself. Physical and operational factors, such as cyclone geometry and size, solids size distribution and density, inlet velocity and other operating conditions, are not included in these models, and the effect of these parameters is thus not thought to be of primary importance. In the Muschelknautz model, on the other hand, the inlet velocity, the cyclone dimensions, and the mean size and density of the inlet solids all feature. 

Fig. 9.1.3. The graphical model of Zenz for estimating the effect of solids loading on cyclone separation efficiency. 1 grain/ft = 2.29 g/m ...

Fig. 10.4.1. Sketch indicating the sampling points for determining cyclone separation efficiency...

Figure 13.7.3 shows the raw efficiency data plotted against superficial air velocity in the cyclones. The fact that the efficiency reduces with increasing gas velocity confirms that re-entrainment, and not separation efficiency of the incoming droplets, is the factor limiting the cyclone separation efficiency. 

---