Column Sizing Example Trays or Packings

Example 9.2 asked (Sec. 9.4.2) whether a packed tower would be better than trays for the depropanizer. The design with trays is in Sec. 6.5.11. For the comparison, it is assumed that filter evaluation of the alternate design (with third-generation packing Sec. 9.4,9) it was found to be sound and not too tight. 

of trays Tray spacing, in Packed height, ft Allowance for distributor, ft Allowance for support ar holddown, ft Total height ft Bottom section  

Large enough to accommodate manhole in pecked tower, also vaper distribution device 

Comment. In this example, a tray tower Is slightly shorter, and otherwise much the same size as a packed tower. In such a case, a tray tower will be preferred both because of the height saving and due to the smaller cost of trays compared to packings plus distributors. Also, the use of a trayad tower in this example will reduce the degree of uncertainty regarding performance prediction. 

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