ABSTRACT
In wet scrubbing, an atomized liquid, usually water, is used to capture particulate dust or to increase the size of aerosols. Increasing size facilitates separation of the particulate from the carrier gas. Wet scrubbing can effectively remove fine particles in the range from 0.1
µ
m to 20
µ
m. The particles may be caught first by the liquid, or first on the scrubber structure, and then washed off by the liquid. Because most conventional scrubbers depend upon some form of inertial collection of particulates as the primary mechanism of capture, scrubbers when used in a conventional way have a limited capacity for controlling fine particulates. Unfortunately inertial forces become insignificantly small as particle size decreases, and collection efficiency decreases rapidly as particle size decreases. As a result, it becomes necessary to greatly increase the energy input to a wet scrubber to significantly improve the efficiency of collection of fine particles. Even with great energy inputs, wet scrubber collection efficiencies are not high with particles less than 1.0
µ
m in size. Wet scrubbers have some unique characteristics useful for fine particulate con-
trol. Since the captured particles are trapped in a liquid, re-entrainment is avoided, and the trapped particles can be easily removed from the collection device. Wet scrubbers can be used with high-temperature gases where cooling of the gas is acceptable and also with potentially explosive gases. Scrubbers are relatively inexpensive when removal of fine particulates is not critical. Also, scrubbers are operated more easily than other sophisticated types of particulate removal equipment.
