Methods of Construction

The components of a stripping tower include the tower shell, tower internals, packing, and air delivery systems. The tower shell can be made of aluminum, fiberglass, stainless steel, or coated carbon steel. Selecting the shell construction material is usually based on cost, structural strength, resistance to corrosion, and esthetics. Table 9.17.5 shows the advantages and disadvantages of several materials of construction.

Tower internals include the water distributor system inside the tower, the mist eliminator system, and the air exhaust ports. The environmental engineer should select the type of components that ensure optimal mass-transfer conditions at the most economical cost.

The packing material is an important component of the air stripping tower. Several types of packing materials are commercially available including plastic, metal, or ceramic

(Perry and Green 1984). The selection is based on materials exhibiting a high mass-transfer rate and a low gas pressure drop. Plastic packings are often used because of their low price, corrosion resistance, and light weight. Table 9.17.6 shows the physical characteristics of common packing materials.

Other components of an air stripping system include the blower, noise control devices, and air filters. The blower is designed based on the air-water ratio and can be mounted on top of the tower or at the base. Sound mufflers control noise, and air filters prevent contact between the water and the air outside the tower.

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