Dust collector

Table 11. Chemical Compatibility of Fibers in Dust Collector Bags...

A. C. Stem, K. J. Caplan, and P. D. Bush, Cyclone Dust Collectors, American Petroleum Institute, New York, 1955. 

R. P. Janoso, "Baghouse Dust Collectors on a Low Sulfur Coal Eired Utihty Boiler," Preprint 74-101, 67th APCA Annual Meeting Denver, Col, June... 

A potential problem for rotary valve usage is that they tend to pull material preferentially from the upside of the valve, which can affect the mass flow pattern. Another problem is that once soHd drops from the vane, the air or gas that replaces it is often pumped back up into the bin. In addition, air can leak around the valve rotor. Such air flows can decrease the soflds flow rates and/or cause flooding problems. A vertical section shown in Figure 13 can alleviate the preferential flow problem because the flow channel expands in this area, usually opening up to the full outlet. To rectify the countercurrent air flow problem, a vent line helps to take the air away to a dust collector or at least back into the top of the bin. 

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). 

Vacuum-shelf dryers require auxiliary stream jets or other vacuum-producing devices, intercondensers for vapor removal, and occasionally wet scrubbers or (heated) bag-type dust collectors. 

Stokes Vacuum, Inc. Prices include shell, 50-lh/in -gaiige jacket, agitator, drive, and motor auxiliary dust collectors, condensers. iLoading with product level on or around the agitator shaft. 

I Price based upon carbon steel construction (motors and secondary dust collectors by others). (1994)... 

Based upon 1200 F air-inlet temperature. With an inlet temperature of 700 F the evaporative capacity would he half that given in the table. Prices are based upon carbon steel construction with cyclone collector (January, 1995). Motors and secondary dust collectors excluded... 

FIG. 14-108 ( 7)Liqi lid entrainment from the bottom of a vessel by centrifugal flow. (Rietema and Veroer, Cyclones in Industry, Elsevier, Amsterdam, 1961. ) (h) Gas-oiitlet sldrt for liquid cyclones. (Stern et al. Cyclone Dust Collectors, Ametican Petroleum Institute, New York, 1955. )... 

The basic operations in dust collection by any device are (1) separation of the gas-borne particles from the gas stream by deposition on a collecting surface (2) retention of the deposit on the surface and (3) removal of the deposit from the surface for recovery or disposal. The separation step requires (1) application of a force that produces a differential motion of a particle relative to the gas and (2) a gas retention time sufficient for the particle to migrate to the coUecting surface. The principal mechanisms of aerosol deposition that are apphed in dust collectors are (1) gravitational deposition, (2) flow-line interception, (3) inertial deposition, (4) diffusional deposition, and (5) electrostatic deposition. Thermal deposition is only a minor factor in practical dust-collectiou equipment because the thermophoretic force is small. Table 17-2 lists these six mechanisms and presents the characteristic... 

Mechanical Centrifugal Separators A number of collectors in which the centrifugal field is supphed by a rotating member are commercially available. In the typical unit shown in Fig. 17-45, the exhauster or fan and dust collector are combined as a single unit. The blades are especially shaped to direct the separated dust into an annular slot leading to the collec tion hopper while the cleaned gas continues to the scroll. 

Electrical precipitators are probably the most versatile of all types of dust collectors. Veiy high collection efficiencies can be obtained regardless of the fineness of the dust, provided that the precipitators are given proper maintenance. The chief disadvantages are the high initial cost and, in some cases, high maintenance costs. Furthermore, caution must be exercised with dusts that are combustible in the carrier gas. 

Solids collection associated with dust collectors and cyclones... 

The principal technological developments in the control of air pollution by engineering during the nineteenth century were the stoker for mechanical firing of coal, the scrubber for removing acid gases from effluent gas streams, cyclone and bag house dust collectors, and the introduction of physical and chemical principles into process design. 

The use of dedicated dust collectors to recycle recovered materials. 

Fortress Designs Supplier of dust control equipment, baghouses, dust collectors, fabric filters, dust filters, bin vents. http ll vww. fabricfilters.com... 

Schrader Environmental Systems, Inc. Air pollution control technologies such as catalytic oxidizers, packed tower wet scrubbers, dust collectors. http //WWW. anseWre. com... 

Bulk alum can be stored in mild steel or concrete bins with dust collector vents located in, above, or adjacent to the equipment room. Recommended storage capacity is about 30 days. Dry alum in bulk form can be transferred or metered by means of screw conveyors, pneumatic conveyors, or bucket elevators made of mild steel. Pneumatic conveyor elbows should have a reinforced backing as the alum can contain abrasive impurities. 

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