Page 310 - Air pollution and greenhouse gases from basic concepts to engineering applications for air emission control

10.2 Control of Particulate Matter Emissions 287

Fig. 10.5 Schematic diagram of typical wet scrubbers

the forces of collision and relative velocity of the droplets with respect to gas
stream. A well designed cyclonic spray tower greatly increases the collection of
particles smaller than 10 μm when compared to simple countercurrent spray towers.
In a venturi scrubber gas meets the liquid at the throat. Atomized water droplets
are added at throat as sprays or jets. Gas first accelerates and then deaccelerates
before and after the throat. As a result, the gas pressure drop is expected to be high
due to the converging and diverging flow pattern. The mixture of gas and liquid
droplets has to be separated again using a downstream unit. It can be a cyclonic
collector or a filter to separate water droplets from air stream.