Cyclones overview

Fig. 13.C.1. Simplified view of cyclone with liquid film of thickness t along waU with gas comprising the core flow. Left image cyclone overview. Right image detail of a vertical segment of the cyclone...

Recently, Pallares and Johnsson [106] presented an overview of the macroscopic semi-empirical models used for the description of the fluid dynamics of circulating fluidized bed combustion units. They summarized the basic modeling concepts and assumptions made for each model together with the major advantages and drawbacks. In order to make a structured analysis of the processes involved, the CFBC unit is often divided into 6 fluid dynamical zones like the bottom bed, freeboard, exit zone, exit duct, cyclone and downcomer and particle seal, which have been shown to exhibit different fluid dynamical behavior. 

The cyclone models illustrated above are meant merely to introduce the reader to the complex subject of particle separation from gases by cyclones. More interested readers should pursue the original references, as well as the brief overview on devices, in Perry and Green (1984, pp. 20-83-20-89). A model of particle separation in a down-exhaust cyclone separator, of uniflow type, is available in Chen et aL (1999b). These separators have a very low gas pressure drop. 

This book strives to provide a long overdue overview of the state of the art in this specialized, albeit, important area of separation technology. Theory and design methods are presented covering the important classical topics, including particle cut-size, grade-efficiency, overall efficiency and pressure drop. In addition, many special topics are covered on basis of the authors experiences and interests. These include discussions and sections on a very wide variety of topics that, in one way or the other, relate to cyclone technology ... 

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