Page 323 - Applied Process Design For Chemical And Petrochemical Plants Volume II

31 2 Applied Process Design for Chemical and Petrochemical Plants

Table 9-33A
Revised Packed Tower Pressure Drop Correlation Constants for Towers Operating Below Flooding Region

m e of Packing 3
._
a 1.04 0.52 0.52 0.13 0.14
Intalox Saddles Ceramic
0.37 0.25 0.16 0.15 0.10
a 1.96 1.31 0.82 0.53 0.31 0.23 0.18
Raschig Rings Ceramic
P 0.56 0.39 0.38 0.22 0.21 0.17 0.15
~ ~ - .-
a 1.16 0.56 0.53 0.21 0.16
Berl Saddles Ceramic
.~ B 0.47 0.25 0.18 0.16 0.12
a 0.22 0.14 0.10
Pall Rings Plastic
B 0.14 0.13 0.12
a 0.43 0.15 0.08 0.06
Pall Rings Metal
P 0.17 0.15 0.16 0.12
~ ~~
Raschig Rings a 1.20
?& in. Wall Metal B 0.28

Raschig Rings a 1 1.59 1.01 0.80 0.53 0.29 0.23
%in. Wall Metal
P 0.29 0.39 0.30 0.19 0.20 0.14
--
By permission J. Eckert, US. Stoneware Go. (now, Norton Chemical Process Equipment Gorp.) (1958).
Equation

Ap = a x loBL '* ' (Limited to Region Below Flooding).
lpcl
Ap = Pressure Drop-in. HnO/ft of packing
G = Gas Mass Velocity-lb/sec ft2
L = Liquid Mass Velocity-lb/sec ft2
p~ = Gas Density-lb/ft3
a and p = Constants.
Pressure Drop Across Packing Supports and
Redistribution Plates

Useful correlated information on pressure drop across
packing supports and redistribution plates is practically
not available. Some order of magnitude guide data is
given in Figures 9-37-41.
Because these data are peculiar to the supports studied,
it can serve only as a good estimate for other situations. It
is important to remember that the results obtained with a
bare plate, and one holding a layer of packing, can be quite
different, the latter being the more realistic condition.
I." The only available test data [44] indicate that the plain flat
0.06 0. I 0.2 0.4 0.6 1.0
plate (2645% free area) has a decided detimental effect
Ap/Ap,,oo* on the allowable flooding conditions of the tower; whereas
the wire screen, weir-type, and fused Raschig ring designs
Figure 9-36. Pressure drop correlation at flooding. Used by permis-
sion of Zenz, F. A., Chemical Engineering, Aug. (1 953) p. 181. have very little effect when using Intalox saddles for packing.