Tower Packing is usually thought of as a mass of inert solid shapes dumped in a cylindrical column for the purpose of providing greater surface area for the gas and liquid in a wet scrubber to make contact. Structured tower packing is thought of in much the same manner, a series of stages are installed in a vertical tower to provide maximum surface area for the gas and liquid to make contact. However, most designers tend to overlook the benefits of an alternative tower packing in a cross or semi-cross flow arrangement.

The cross or semi-cross wet scrubber combines spray and packed bed sections followed by a mist eliminator in a horizontal box for maximum separation of soluble gases, particulate matter, and mist particles below 0.5 mm size. These scrubbers are usually classified as medium energy scrubbers and have a pressure drop of 150-230 mm water gauge, although they can be higher energy depending on the system requirements.

Kimre recognizes that a single vessel can contain the following stages:

Precooling and wetting

Pre-cleaning of particulate matter

Humidification and cooling

Separation of medium to large size particles

Stage-wise absorption of soluble gases

Simultaneous collection of fine to medium size particulates

Direct contact heat transfer

Final separation of fine particles, mist, and aerosols