Cyclone design

Centrifugal demister or cyclone) devices rely on high velocities to remove liquid particles and substantial pressure drops are required in cyclone design to generate these velocities. Cyclones have a limited range over which they operate efficiently this is a disadvantage if the input stream flowrate is very variable. 

Fig. 9. Dimension ratios ofLapple (134) cyclone design. From Ref. 160,...

N. L. Giuricich and B. Kalen, "Dominant Criteria ia ECC Cyclone Design," presented at Katalistiks 3rdA.nnualFCC Symposium, Amsterdam, The Nethedands, May 1982. 

Centrifugal Separation Centrifugal force can be utilized to enhance particle collection to several hundredfold that of gravity. The design of cyclone separators for dust removal is treated in detail in Sec. 17 under Gas-Solids Separations, and typical cyclone designs are shown in Fig. 17-43. Dimension ratios for one family of cyclones are given in Fig. 17-36. Cyclones, if carefully designed, can be more efficient on hquids than on solids since liquids coalesce on capture and are easy to drain from the unit. However, some precautions not needed for solid cyclones are necessary to prevent reentrainment. 

FIG. 17-43 Some commercial cyclone design alternatives, (Couttesy ofPSRI, Chicago.)... 

The collection efficiency of cyclones varies as a function of particle size and cyclone design. Cyclone efficiency generally increases with (1) particle size and/or density, (2) inlet duct velocity, (3) cyclone body length, (4) number of gas revolutions in the cyclone, (5) ratio of cyclone body diameter to gas exit diameter, (6) dust loading, and (7) smoothness of the cyclone inner wall. Cyclone efficiency will decrease with increases in (1) gas viscosity, (2) body diameter, (3) gas exit diameter, (4) gas inlet duct area, and (5) gas density. A common factor contributing to decreased control efficiencies in cyclones is leakage of air into the dust outlet (EPA, 1998). 

Coker, A. K., Understanding cyclone design, Chem. Eng Progr, pp. 51-55, December 1993. 

Liquid Cyclone Design (Based on air-water at atmospheric pressure) Figure 4-49... 

Figure 9-2. Lummus direct-coupled cyclone design.

Figure 10.48. Proposed cyclone design, all dimensions mm (Example 10.4)...

Figure 8.8 Collection efficiency curve for the cyclone design in Example 8.1.

Antunes M, RA Medronho. Bradley cyclones Design and performance analysis. In L Svarovsky, MT Thew, eds. Hydrocylcones Analysis and Applications. Boston Kluwer, 1992, p 3-13. 

Figure 21. Attrition extent caused by a conventional cyclone and by the new cyclone design suggested by Molerus and Gliickler (1996).

The broad spectrum of derived fractional efficiency curves in Fig. 2 simply reflects the effects of cyclone designs deviating from consistence with the basic premises and from ill defined particle characteristics. 

All cyclone design procedures bear the inherent condition that the solids enter uniformly dispersed over the cyclone s inlet area. This is generally the case where a cyclone is hung inside a vessel above a... 

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