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Random Dumped Packed Bed Calculation


Packed bed pressure drop and flooding calculations are based on the Eckert generalized pressure drop correlation. The flooding calculation has been shown to be non-conservative. The problem is most pronounced in low pressure columns. For instance Eckert will report an atmospheric column stripping air with 4 GPM/ft² water irrigation rate operating at roughly 90% of flood as operating in the low 70%s.


Charles Holland reports that Bolles and Fair suggest using a 1.32 safety factor (multiplier) on the Eckert correlation for a 95% confidence estimate of flooding. They further suggest a 2.2 safety factor on the Eckert correlation for a 95% confidence estimate of the pressure drop.

 



Table of Packing F Values

Packing Type

6mm

13mm

19mm

25mm

38mm

50mm

75mm

100mm

Berl Saddles, ceramic

2950/m

790/m

-

360/m

215/m

150/m

-

-

Intalox Saddles, ceramic

2380/m

660/m

-

320/m

170/m

130/m

70/m

-

Intalox Saddles, plastic

-

-

-

105/m

-

69/m

50/m

-

Pall Rings, metal

-

-

-

157/m

92/m

66/m

-

-

Raschig Rings, ceramic

5250/m

2000/m

840/m

510/m

310/m

215/m

120/m

-

Raschig Rings, metal

-

-

730/m

450/m

270/m

187/m

105/m

-


References:

  • John Eckert et. al., "Fundamentals of Multicomponent Distillation," Chemical Engineering Progress (January 1966) p. 59-67.
  • John Eckert, "Selecting the Proper Distillation Column Packing," Chemical Engineering Progress (March 1970) p. 39-44.
  • John Fair, PhD. et. al., Perry's Chemical Engineer's Handbook 6th Ed. (New York, New York: McGraw-Hill Book Co., 1984), p. 18-22 - 18-24.
  • Charles Holland, PhD, Fundamentals of Multicomponent Distillation (New York, New York: McGraw-Hill Book Co., 1981), p. 470 - 474.

    Random Dumped Packed Bed Calculation
    Copyrighted 2000, 2004
    Last updated 19Sep04