scrubbing liquid
and temperature. As with sorbents
a scrubbing medium is limited in the amount of a gas it can absorb. On saturation
it cannot absorb additional gases. In most packed tower scrubbers
the liquid is recirculated from a sump. Fresh scrubbing liquid is added and used liquid is withdrawn continuously to prevent saturation. Collection efficiency in scrubbers is enhanced by using a packing medium. Packing media include steel
ceramic
or thermoplastic materials. These materials come in a variety of shapes and have a characteristically large surface area. By providing a large surface area over which the scrubbing liquid is spread
a greater contact area is provided
thereby increasing collection efficiency. Thermosetting plastics are the most widely used packing materials. They are less subject to corrosion and pressure drop than metal or ceramic types. A plastic packing material can be seen in the photograph in Figure 10.11. Figure 10.11 Plastic packing material used in a scrubber. (Courtesy of Lantec Products
Inc.) Scrubbers experience a number of operating and maintenance problems. These include corrosion of scrubber surfaces and plugging of the packed beds. To reduce corrosion
internal scrubber surfaces need to be constructed with stainless steel
lined steel
exotic metals
polyvinyl chloride
or fiberglass-reinforced plastic. Fiberglass or lined steel is commonly used to reduce costs. Plugging may occur as a result of the deposition of Control of emissions from stationary sources 361
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