Dust collection equipment

Environmental Pollution Control. The cement iadustry has had an iatensive program of capital expenditure to iastaH dust collection equipment on kilns and coolers siace the 1970s (60). Modem equipment collects dust at 99.8% efficiency. Many smaller dust collectors are iastaHed ia aew plants (61). 

Most forms of dust-collection equipment use more than one of the collection mechanisms, and in some instances the controlhng mechanism may change when the collec tor is operated over a wide range of conditions. Consequently, collectors are most conveniently classified by type rather than according to the underlying mechanisms that may be operating. 

Good housekeeping practices are key to minimizing losses and preventing fugitive emissions. Losses and emissions are minimized by enclosed buildings, covered conveyors and transfer points, and dust collection equipment. Yards should be paved and runoff water routed to settling ponds. 

Table 4-5 [10] summarizes dry dust particle separators as to general application in industry, and Table 4-6 and Figures 4-4 and 4-5 [42] compare basic collector characteristics. Figure 4-5 presents a typical summary of dust collection equipment efficiencies which have not changed significantly for many years except for specialized equipment to specialized applications. 

Figure 4-5. Efficiency curves for various types of dust collection equipment as of 1969. Only marginal improvements have been made since then. By permission, Sargent, G. D., Chemical Engineering, Jan. 27,1969, p. 130.

By permission, John M. Kane, Operation, Application and Effectiveness of Dust Collection Equipment, Heating and Ventilating. Aug. 1952, Ref. (10)... 

Kane, John M., Guideposts Tell Flow To Select Dust Collecting Equipment," Plant Engineering, November 1954. 

A widely used type of dust-collection equipment is the cyclone separator. A cyclone is essentially a settling chamber in which gravitational acceleration is replaced by centrifugal acceleration. Dust-laden air or gas enters a cylindrical or conical chamber tangentially at one or more points and leaves through a central opening. The dust particles, by virtue of their inertia, tend to move toward the outside separator wall from where they are... 

See reference 36 for discussion of various types of dust collection equipment. Fabric filters will be used in order to recover all the fines in a dry state. These should recover 99% of the material larger than 0.2 microns.36 A continuous-envelope fabric filter will be used, since this seems to have the lowest annual costs. For this filter ft3 of surface area is required for about each 2 ft3/min of air. 

Table 8-1 1 gives the pressure drop and utility requirements for dust collection equipment. 

Pressure Drop and Utility Requirements in Dust Collecting Equipment... 

Source Sargent, G.D. Dust Collection Equipment, Chemical Engineering, Jan. 27, 1969, p. 130. 

Thermal deposition is only a minor factor in practical dust-collection equipment because the thermophoretic force is small. Table 17-2 lists these six mechanisms and presents the characteristic parameters of their operation [Lundeand Lapple, Chem. Eng. Prog., 53,385 (1957)]. The actions of the inertial-deposition, flow-line-interception, and diffu-sional-deposition mechanisms are illustrated in Fig. 17-35 for the case of a collecting body immersed in a particle-laden gas stream. 

Cyclone Separators The most widely used type of dust-collection equipment is the cyclone, in which dust-laden gas enters a cylindrical or conical chamber tangentially at one or more points and... 

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