1. Numerical Analysis on Separation of Methane through Hollow Fiber Membrane Module: Cascade Operation
Yongtaek Lee, Ph.D., Professor
Dept. of Chemical Engineering Chungnam National University

2. Flow configuration.
Operation program.
Results date file

3. Flow configuration in a module
Counter-current type.
PC operating system
MS Windows 7.
Computer program
Compaq Visual Fortran 6.6 .

4. Process design 1단 2단 1단 2단 3단 1단 2단 2 - stage process system

5. 2 – stage process system flow chart
(Model A)
(Model B)

6. 2 – stage process system flow chart

7. Operating conditions 2 – stage process system
Concentration of methane in feed stream (%) 50
Flow rate of feed stream (L/min)
50 ~ 100
Length of hollow fiber membrane module (m)
0.36
Area of membrane in module (m2)
1.71 ~ 3.42
Operating temperature (K)
298.15
Pressure of permeate stream (atm) 1
Pressure of feed stream (atm)
5, 10, 20

8. Effect of feed pressure in feed stream :
Pressure of permeate = 1 atm
<Model A> 1단 2단
1-stage pressure (atm) 10 20
2-stage pressure (atm)
Pressure of a feed (atm)
10, 20
Concentration of methane in feed stream (%) 50
Pressure of a permeate (atm) 1
Flow rate (L/min)
50 ~ 100
1-stage area of membrane in module (m2)
1.71
2-stage area of membrane in module (m2)
Length membrane module (m)
0.36
Operating temperature (K)
298.15
mole fraction of CH4 in retentate. Vs. Flow rate

9. Effect of feed pressure in feed stream :
Pressure of permeate = 1 atm
<Model A> 1단 2단
1-stage pressure (atm) 10 20
2-stage pressure (atm)
Pressure of a feed (atm)
10, 20
Concentration of methane in feed stream (%) 50
Pressure of a permeate (atm) 1
Flow rate (L/min)
50 ~ 100
1-stage area of membrane in module (m2)
1.71
2-stage area of membrane in module (m2)
Length membrane module (m)
0.36
Operating temperature (K)
298.15
Recovery CH4 Vs. Flow rate

10. Effect of membrane area in feed stream :
Pressure of permeate = 1 atm
<Model A> 1단 2단
1-stage area (m2)
1.71
2.34
3.42
2-stage area (m2)
Pressure of a feed (atm) 10
Concentration of methane in feed stream (%) 50
Pressure of a permeate (atm) 1
Flow rate (L/min)
50 ~ 100
Area of membrane in module (m2)
1.71, 2.34, 3.42
Length membrane module (m)
0.36
Operating temperature (K)
298.15
Mole fraction of CH4 in retentate. Vs. Flow rate

11. Effect of membrane area in feed stream :
Pressure of permeate = 1 atm
<Model A> 1단 2단
1-stage area (m2)
1.71
2.34
3.42
2-stage area (m2)
Pressure of a feed (atm) 10
Concentration of methane in feed stream (%) 50
Pressure of a permeate (atm) 1
Flow rate (L/min)
50 ~ 100
Area of membrane in module (m2)
1.71, 2.34, 3.42
Length membrane module (m)
0.36
Operating temperature (K)
298.15
Recovery CH4 vs. Flow rate

12. Effect of feed pressure in feed stream
Pressure of permeate = 1 atm
<Model B> 1단 2단
1-stage pressure (atm) 10 20
2-stage pressure (atm)
Pressure of a feed (atm)
10, 20
Concentration of methane in feed stream (%) 50
Pressure of a permeate (atm) 1
Flow rate (L/min)
50 ~ 100
1-stage area of membrane in module (m2)
1.71
2-stage area of membrane in module (m2)
Length membrane module (m)
0.36
Operating temperature (K)
298.15
Feed mole fraction of CH4 in retentate. Vs. Flow rate

13. Effect of feed pressure in feed stream
Pressure of permeate = 1 atm
<Model B> 1단 2단
1-stage pressure (atm) 10 20
2-stage pressure (atm)
Pressure of a feed (atm)
10, 20
Concentration of methane in feed stream (%) 50
Pressure of a permeate (atm) 1
Flow rate (L/min)
50 ~ 100
1-stage area of membrane in module (m2)
1.71
2-stage area of membrane in module (m2)
Length membrane module (m)
0.36
Operating temperature (K)
298.15
Recovery CH4 vs. Flow rate

14. Effect of membrane area in feed stream
Pressure of permeate = 1 atm
<Model B> 1단 2단
1-stage area (m2)
1.71
2.34
3.42
2-stage area (m2)
Pressure of a feed (atm) 10
Concentration of methane in feed stream (%) 50
Pressure of a permeate (atm) 1
Flow rate (L/min)
50 ~ 100
Area of membrane in module (m2)
1.71, 2.34, 3.42
Length membrane module (m)
0.36
Operating temperature (K)
298.15
Feed mole fraction of CH4 in retentate. Vs. Flow rate

15. Effect of membrane area in feed stream
Pressure of permeate = 1 atm
<Model B> 1단 2단
1-stage area (m2)
1.71
2.34
3.42
2-stage area (m2)
Pressure of a feed (atm) 10
Concentration of methane in feed stream (%) 50
Pressure of a permeate (atm) 1
Flow rate (L/min)
50 ~ 100
Area of membrane in module (m2)
1.71, 2.34, 3.42
Length membrane module (m)
0.36
Operating temperature (K)
298.15
Recovery CH4 vs. Flow rate

16. Mole fraction of CH4 in retentate vs. Membrane area2단
(A) 1단 1단
(B) 2단
Pressure of a feed (atm) 10
Concentration of methane in feed stream (%) 50
Pressure of a permeate (atm) 1
Flow rate (L/min) 70
Area of membrane in module (m2)
1.71, 2.34, 3.42
Length membrane module (m)
0.36
Operating temperature (K)
298.15
Mole fraction of CH4 in retentate vs. Membrane area

17. Recovery of CH4 Vs. Membrane area2단
(A) 1단 1단
(B) 2단
Pressure of a feed (atm) 10
Concentration of methane in feed stream (%) 50
Pressure of a permeate (atm) 1
Flow rate (L/min) 70
Area of membrane in module (m2)
1.71, 2.34, 3.42
Length membrane module (m)
0.36
Operating temperature (K)
298.15
Recovery of CH4 Vs. Membrane area

18. Operating condition 3 – stage process system
Concentration of methane in feed stream (%) 50
Flow rate of feed stream (L/min)
100 ~
Length of hollow fiber membrane module (m)
0.36
Area of membrane in module (m2)
1.71, 4.87, 5.13
Operating temperature (K)
298.15
Pressure of permeate stream (atm) 1
Pressure of feed stream (atm)
8, 10

19. Case. I 1단 2단 3단 Mole fraction of CH4 (%) Flow rate (L/min) Feed 50 58
1st stage
Permeate
Retentate
29.71
2.04
36.22
109.08
20.78
88.3
2nd stage
38.01
5.28
64.61
118.71
53.23
65.48
3rd stage
34.5
95.17
32.98
32.49
Final recovery 1단 2단 3단 기본 수정
1-stage area (m2)
1.71
2-stage area (m2)
5.13
3-stage area (m2)
Pressure of a feed (atm) 10
Concentration of methane in feed stream (%) 50
Pressure of a permeate (atm) 1
Flow rate (L/min) 58
1-stage area of membrane in module (m2)
1.71
2-stage area of membrane in module (m2)
5.13
3-stage area of membrane in module (m2)
Length membrane module (m)
0.36
Operating temperature (K)
298.15

20. Case. II 1단 2단 3단 Mole fraction of CH4 (%) Flow rate (L/min) Feed 5054
1st stage
Permeate
Retentate
29.24
1.98
36.09
102.98
20.67
82.31
2nd stage
37.31
5.04
63.92
111.89
50.56
61.32
3rd stage
33.82
95.19
31.24
30.08
Final recovery 1단 2단 3단 기본 수정
1-stage area (m2)
1.71
2-stage area (m2)
4.87
3-stage area (m2)
Pressure of a feed (atm) 10
Concentration of methane in feed stream (%) 50
Pressure of a permeate (atm) 1
Flow rate (L/min) 54
1-stage area of membrane in module (m2)
1.71
2-stage area of membrane in module (m2)
4.87
3-stage area of membrane in module (m2)
Length membrane module (m)
0.36
Operating temperature (K)
298.15

21. Case. III 1단 2단 3단 Mole fraction of CH4 (%) Flow rate (L/min) Feed 5042
1st stage
Permeate
Retentate
28.38
1.7
35.47
81.06
17.03
64.02
2nd stage
36.09
4.26
64.55
85.32
40.27
45.04
3rd stage
32.46
95.38
22.07
22.96
Final recovery 1단 2단 3단 기본 수정
1-stage area (m2)
1.71
2-stage area (m2)
4.87
3-stage area (m2)
Pressure of a feed (atm) 8
Concentration of methane in feed stream (%) 50
Pressure of a permeate (atm) 1
Flow rate (L/min) 42
1-stage area of membrane in module (m2)
1.71
2-stage area of membrane in module (m2)
4.87
3-stage area of membrane in module (m2)
Length membrane module (m)
0.36
Operating temperature (K)
298.15

22. Case. I vs Case. II 1단 2단 3단 Case. I Case. II 1-stage area (m2) 1.71
4.87
5.13
3-stage area (m2)
Pressure of a feed (atm) 10
Concentration of methane in feed stream (%) 50
Pressure of a permeate (atm) 1
1-stage area of membrane in module (m2)
1.71
Length membrane module (m)
0.36
Operating temperature (K)
298.15

23. Case. II vs Case. III 1단 2단 3단
Case. II
Case. III
1-stage pressure (atm) 8 10
2-stage pressure (atm)
3-stage pressure (atm)
Concentration of methane in feed stream (%) 50
Pressure of a permeate (atm) 1
1-stage area of membrane in module (m2)
1.71
2-stage area of membrane in module (m2)
4.87
3-stage area of membrane in module (m2)
Length membrane module (m)
0.36
Operating temperature (K)
298.15
압력을 20 atm 으로 높일 경우 회수율을 얻기가 어려움. 따라서 적정 압력 필요.

24. Summary
The target could not be obtained through the two stage membrane systems of Model A and Model B in terms of the purity and the recovery of methane.
The three stage membrane system can provide the successful purity and the recovery of methane.
Another type of the membrane cascade system may be more useful to get the final goals of purity and recovery.