Page 358 - Applied Process Design For Chemical And Petrochemical Plants Volume II

Packed Towers 347

56

c
.- 52
oc
-0
- 'Z 48
.- -
0
In '=
-0
c-
is .3 44
ma
cm
r .E 40
on
.-
L .cL
CL
w 36
= 0.75

4 Figure 9-70. Colburn Plot for transfer
units. Reproduced by permission of
the American Chemical Society; Col-
burn, A. P., Ind. Eng. Chem. V. 33
M or yI/y2 (See Table9-40.) (1 941) p. 459; all rights reserved.
Equilibrium y * (+)

1
79.4
Assume y Calculated x1 -= 1 1 = -
=
y - y * 0.03 - 0.0174 0.0126
0.03 0.0116 0.0174 79.4
0.025 0.0096 0.0144 94.4 Area Under Curve
0.02 0.0076 0.01 14 116.4 Figure 9-71 is a summation of steps indicated, or the area
0.015 0.0056 0.0084 151.4 can be circumscribed with a planimeter and evaluated.
0.01 0.0036 0.0054 217. Area = 6.27 units, then number of transfer units,
0.005 0.0016 0.0024 384. NOG = 6.27
0.001 0 0 1000.
Height of Transfer Unit
Example: Calculate x, as illustrated for pointy = 0.015
From data of Mehta and Parekh for 1-in. Berl Saddles
200 (0.015 - 0.001) = 500 ~1 ~401,
200 (0.014) = 500 XI HOG = 0.86 ft
Height of packed section:

Z = (6.27) (0.86) = 3.4 ft
Calculate the equilibrium values, p, as illustrated for point of
XI = 0.0116 Total Packed Height Recommended
Process packed height = 5.4 ft
y" = 1.5 (0.0116) = 0.0174 Distribution packed height = 2.00
Total 7.4 ft
Calculate l/(y - y*) for point corresponding to: x1 = 0.0116
where y* = 0.0174 Use: 8.5 to 10 ft of 1-in. Berl saddles