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Separator Design 327

0.3
0.2 2 In. Metal Pall rings
11/2 In. Metal Pall rings
1 in. Metal Pall rings

Ceramic Raschig rings

0.05 O.I 0.2 0.5 1.0
w
Flow Parameter, (rn, ML / mv My) (PL / Pv) ,
Figure 6.19 Flooding factor for packed columns. From Ref. 52 with per-
mission.

Example 6.6 Stripping Methylene Chloride from Wastewater_________

A wastewater stream contains 100 ppm of methylene chloride. One million gal-
lons a day of water will be stripped of the methylene chloride using air. If 99% of
the methylene chloride is removed, what will be the size of the separator?

Data
MWofair 2.9
wastewater temperature 1 00 °F (37.78 °C)
water viscosity 0.703 cP (7.03x10"" Pa-s) (1.47 x 10" Ib/ft-s)
3
water density 62.00 lb/ft 3 (993 kg/m )
air temperature 100 °F and saturated with water
3
air density (100 °F and 1 arm) 0.07395 lb/ft 3 (1.1 8 kg/m )
surface tension of water 69 dynes/cm (0.069 N/m)
Either steam or air could be used to remove methylene chloride from the
wastewater stream. Air will be used in this design. To simplify the problem, as-
sume that the air is saturated with water. If the air is dry, the temperature in the
column will vary because water will evaporate into the air, cooling the water.
Follow the procedures outlined in Tables 6.22 and 6.24 for calculating the

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