Environmental Engineering Reference
In-Depth Information
=
.
x
N
0
05
y
N
+
1
=
0 [note that the solvent stream doesn't always have to be pure solvent].
Equilibrium line:
From the given
K
d
, the equilibrium relationship is
y
1.6
x
. The equilibrium line was
plotted (Figure 5.25) as
Y
vs
X
, using the relationship between weight fractions (
x
,
y
)
and weight ratios (
X
,
Y
)given in Equation (5.17).
=
Operating line:
Since points on the operating line are passing streams, we can plot the operating line
using the given information about the passing streams above Stage 1 and below Stage
N
.
These points are (
X
D
,
Y
N
+
1
); remember to convert to ratios.
Stepping off stages (see Figure 5.25):
(a) Two equilibrium stages are required.
(b) The ratio of water to 1-butanol is:
Y
1
−
Y
1
) and (
X
N
,
Y
N
+
1
X
0
−
0
.
106
−
0
X
N
=
005
=
0
.
85;
0
.
13
−
0
.
this is the slope of the operating line:
F
D
/
F
S
.
0.45
Equilibrium line
0.4
0.35
0.3
0.25
0.2
0.15
1
Y
1
0.1
Operating line
2
0.05
3
4
0
0
0 .0 5
0 .1
0. 15
0.2
0 .2 5
X
D
Y
N
+1
X
N
X
(kg acetic acid kg water)
Figure 5.25
Countercurrent immiscible extraction, Example 5.5.
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