Applicability

Wet scrubbers have numerous industrial applications and few limitations. They are capable of collecting basically any type of dust, including flammable, explosive, moist, or sticky dusts. In addition, they can collect suspended liquids (i.e. mists) or gases alone or with PM simultaneously. However, while scrubbers have many potential applications, there are some characteristics that limit their use. The most significant consideration is the relatively low collection efficiency for fine PM, especially those less than 1.0 :m in diameter. Therefore, conventional scrubbers may not be suitable for processes which emit many submicrometer particles. As discussed above venturi, condensation, and charged scrubbers are capable of collecting submicrometer particles at higher efficiencies than other scrubbers and, therefore, can be used effectively in applications where there are a large percentage of fine PM in the gas stream.

Gas stream composition may also be a limiting factor in scrubber application for a specific industry, since wet scrubbers are very susceptible to corrosion. The use of wet scrubbers also may not be desirable when collecting valuable dust which can be recycled or sold. Since scrubbers discharge collected dust in the form of a wet slurry, reclaiming clean dry dust from this slurry is often inconvenient and expensive. Because of design constraints, particulate scrubbers are generally not used in very large installations, such as utilities where gas flowrates exceed 250,000 ACFM, since multiple scrubbers are needed once flowrates exceed 60,000-75,000 ACFM.

Table 1 lists current applications of wet scrubbers.It should be noted that the level of PM control supplied by each of the scrubber types listed in Table 1  will vary according to the level of control currently required by each industry and/or facility. The driving

force for PM control in many industries and/or facilities is the Federal, State, and local air pollution

regulations. As more stringent PM regulations are put into place, a shift toward the use of higher

efficiency scrubbers is likely to occur. Table 2 rates the various scrubber types according to their

potential for controlling fine particles