A vertical counterflow spray chamber has a contact zone of 2.0 m and operates with a liquid-to-gas ratio of 1.3 L/m3 and an average droplet diameter of 200 microns. During a trial operation, the following data were collected in the unit: average wash temperature 30°C, gas velocity 0.4 m/s, input loading 5 g/m3. The particle size distribution obtained from a successive impaction device is as follows:
Size Range, Îźm
<5 , 5-8 ,8-16, 16-30 , 30-50, >50
Mass, mg
40 , 80 , 120 , 80 ,20 ,10
Estimate the overall efficiency of the unit, assuming a 20% utilization of the spray droplets.