Environmental Engineering Reference
In-Depth Information
Example 9.1
Problem:
Based on the dual-mode transport model, calculate the pure component and mixtures
permeability of CO
2
and CH
4
using a polysulfone membrane. The gas pressure is
10 atm for each component.
D
D
10
8
cm
2
k
D
C
H
cc(STP)
cc(STP)
cm
3
b
(atm
−
1
)
F
s
cm
3
·
atm
CO
2
0.664
4.40
17.90
0.326
0.105
CH
4
0.161
0.44
9.86
0.070
0.349
Solution:
Dual-mode model:
Pure-component calculation
:
k
D
D
D
1
C
H
b
k
D
KF
=
Q
+
K
=
1
+
bP
17
(0
.
90(0
.
326)
.
105)
0
.
664
1
10
−
8
)
Q
CO
2
=
0
.
664(4
.
40
×
+
1
+
0
.
326(10 atm)
cc(STP)
cm
10
−
8
Q
CO
2
=
3
.
55
×
·
s
·
atm
(9
.
86)(0
.
070)(0
.
349)
0
.
161
10
−
8
)
1
Q
CH
4
=
0
.
161(0
.
444
×
+
1
+
0
.
070(10 atm)
cc(STP)
cm
10
−
9
Q
CH
4
=
1
.
34
×
·
s
·
atm
Q
CO
2
α
ideal
=
Q
CH
4
=
26
.
Mixture calculation
:
k
Di
D
Di
1
K
i
F
i
Q
i
=
+
1
+
b
i
P
i
+
b
j
P
i
Note the two
bP
terms in the denominator - this takes into account
the competitive nature of the transport.
17
.
90(0
.
326)
(0
.
105)
0
.
664
1
10
−
8
)
Q
CO
2
=
0
.
664(4
.
4
×
+
1
+
0
.
326(10)
+
0
.
07(10)
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