Cyclone dust separator

Figure 4-46. General efficiency curves, applies specifically to helical entry cyclone dust separators. Courtesy of The Ducon Co.

Figure 4-47. General efficiency curve applies specifically to involute entry cyclone dust separators. Courtesy of American Blow/er Div., American Radiator and Standard Sanitary Corp.

Figure 7.2-11. Spray drier with heat recovery system 1. Spray tower and drying system 2. Air heater 3. Air fan 4. Cyclone dust separator 5. Wet dust separator and entrainment separator 6. Exhaust air fan 7. Pneumatic product conveyer 8. Intermediate product storage 9. Product sieving and packing 10. Wet product pumping system (by courtesy of BMA, TAG-Division). 

Cristea E. D., Malfa, E., and Coghe, A. "3D Simulations and Measurements of Strongly Swirling Heavy Laden Flow Inside Cyclone Dust Separator." 3rd International Symposium on Engineering Turbulence Modeling and Measurements, May 27-28, 1996, Crete, Greece. 

Belevitsky, A. M. Economy and Technical and Economic Optimisationof Dust-Collecting Plants (on an Example of Installations of Cyclonic Dust Separation) Help Supervising Material. Clearing of Gas Emissions L. 1982. 

Other Centrifugal Collectors. Cyclones and modified centrifugal collectors are often used to remove entrained Hquids from a gas stream. Cyclones for this purpose have been described (167—169). The rotary stream dust separator (170,171), a newer dry centrifugal collector with improved collection efficiency on particles down to 1—2 pm, is considered more expensive and hence has been found less attractive than cyclones unless improved collection in the 2—10-pm particle range is a necessity. A number of inertial centrifugal force devices as well as some others termed dynamic collectors have been described in the Hterature (170). 

Dust Separation It is usuaUy necessaiy to recover the solids carried by the gas leaving the disengaging space or freeboard of the fluidized becl GeneraUy, cyclones are used to remove the major portion of these sohds (see Gas-Sohds Separation ). However, in a few cases, usuaUy on small-scale units, filters are employed without the use of cyclones to reduce the loading of solids in the gas. For high-temperature usage, either porous ceramic or sintered metal has been employed. Multiple units must be provided so that one unit can be blown back with clean gas while one or more are filtering. 

This dust separated by pneumatic filters or cyclones can be recycled and used as internal seeds (disperse phase) for the production of new particles or for the layered growth (continuous phase) of existing particles. One effect of the production of internal seeds is the formation of a wide particle size distribution, while the deposition of the re-fed dust yields to growth of particles. 

FIGURE 3.2-7 Potential problems of vapor-liquid tangential separators. From Stem et al.. Cyclone Dust Collectors. American Petroleum Institute, New York, 1935. 

The separation efficiency of such a unit is high, and is comparable with values achieved with the best cyclones. These separators, however, have higher maintenance requirements and they are unsuitable in the case of abrasive and sticking dusts. 

The deionized sol is filtered to remove traces of resin, and is spray-dried in a spray drier using two-fluid atomization. This type of drier is described in The Chemical Engineer s Handbook, 3rd Edition, by John H. Perry, McGraw-Hill, New York, 1950 p. 840. The inlet temperature is 300°C and the outlet temperature is 110°C. The dried powder is separated from the air stream in a cyclone-type separator and dust bag filter. The powder is stored out of contact with moisture. 

Another cyclone may be provided at the exit gases in series to improve dust separation. 

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