Environmental Engineering Reference
In-Depth Information
Using constants for 1-inch Berl saddles:
97(250) 0 . 36 (1
3) 0 . 5
(4000) 0 . 4
H G =
1
.
.
/
=
0
.
6ft
.
10 3 (592) 0 . 5 4000
2
0 . 28
H L =
5
.
9
×
.
5
=
1
.
13 ft
.
mV
L
H OG =
H G +
H L
26(250)
4000
=
0
.
6ft
+
(1
.
13 ft)
=
2
.
44 ft
.
mV
L
A
=
26(250)
4000
=
=
1
.
63
.
y A out =
x A in
=
0
mx A in =
0
ln A
y A in
1
mx A in
1
A
+
y A out
A
mx A in
N OG =
A
1
A
0
0
.
.
63
02
1
+
1
.
63
0
.
001
1
.
63
=
ln
0
.
63
1
.
63
=
5
.
45
.
Column height,
z
=
H OG N OG
=
(2
.
44 ft)(5
.
45)
=
13
.
3ft
.
Example 6.6: packed column absorption
Problem:
Air at 25 Cisused to dry a plastic sheet containing acetone. At the drier exit, the
air leaves containing 0.02 mole fraction acetone. The acetone is to be recovered by
absorption with water in a packed tower. The gas composition is to be reduced to
5
×
10 3
=
.
mole fraction at the column exit. The equilibrium relationship is y
1
8 x .
The gas enters the bottom of the column (Figure 6.12) at a flux of 1000 lb m /
ft 2
·
hr,
and the water enters the top at a flux of 1400 lb m /
hr. The tower is packed with
1-inch Berl saddles. Calculate the column height, given:
Water
Sc L =
ft 2
·
915
µ =
12 lb m /
ft
·
hr
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