Staged columns weirs

In Problem 13.3, 7.1 actual stages were required to remove a certain amount of acetone from wet air. What are the column diameter, pressure drop, and actual number of stages if the airflow rate is 35,300 actual ftVmin (1000 actual mVmin) A tray spacing of 24 in (610 mm) will be used. Weir height = 50 mm. 

The gas load, expressed as F-factor, is typically in the range from 1 to 2 Pa. The liquid load referred to weir length / can be varied from approximately 2 to 100 m /(m h). The pressure drop of tray columns is rather high, typically 7 mbar per equilibrium stage. Thus, tray columns are not very well suited for vacuum services. 

Finally, the Hydraulics page tab is clicked, and the window shown in Figure 7.3 opens, on which stage numbers (2 through 31) and the column diameter (5.91 m) are entered. The default values of weir height and tray spacing are 0.05 and 0.6096 m, respectively. 

D3. The calculations in Example 10-3 were done for conditions at the top of the column. Physical properties will vary throughout the column, but columns are normally constructed with identical trays, downcomers, weirs, etc., on every stage (this is sinpler and cheaper). For a 12-foot diameter column, calculate entrainment, pressure drops, downcomer residence time, and weeping at the bottom of the column. The results of Problem 10.D2 are required. If the column will not operate, will it work if the gap between the tray and downcomer apron is increased to 1.5 inches ... 

Acid is not pumped between columns interstage flows are by gravity. In the singleshell column, accumulated acid overflows a weir from one stage to the next below. When separate shells are used, the arrangement of the piping provides the same effect. 

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