Example 5.3:
Calculate the sedimentation rate in gravity separation and centrifugal separation for the particle size limiting to dlim = 7 µm. The particle density = 1040 kg/m3 ; liquid density = 1000 kg/m3 ; Viscosity of continuous phase = 1x10-3 N-s/m2
Solution:
For gravity separation
........................= 1x10-6 m/sec
In centrifugal separation, the sedimentation rate
.........................u = 0.558 x 10-2 m/sec
Ratio of sedimentation rate in centrifugal to gravity separator = 
= 5580
7. SCRUBBEERS
Scrubbers are most often used as an air pollution control device to remove particulate matters and chemicals from waste gas streams of stationary point source. They are also applied where the slurry is used in other parts of the process or where the mixture is in a slurry form. In some scrubbers are applied so that chemical reaction will be generated within the scrubbing action.