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th e r m o c o u p le
CO
H 2O
2
MFC
a d d itiv e g a s
h e a te r MFC
P la s m a R e a c to r v e n t to a tm o s p h e r e
TC D G C S K C a rb o n
5 L ittre
b u b b le f lo w m e te r
w e t te s t m e te r
Figure 1. Schematic diagram of experimental set up
1
6000
0.45
Voltage waveform
Current waveform
0.30
Current (Ampere)
Voltage (Volt)
4000 2000 0 -2000
0.15 0.00 -0.15 -0.30
-4000
-0.45
-6000 -2e-5
-1e-5
0
1e-5
2e-5
-2e-5
-1e-5
Time (second)
0
Time (second)
Figure 2. Voltage and current waveforms
2
1e-5
2e-5
25
Conversion (%)
20
15
10
5
0 0.0
0.8
0.9
1.0
1.1
1.2
1.3
1.4
Gas flow rate (L/min)
Figure 3. Effect of gas flow rate on CO2 conversion. Data was taken at fixed power frequency 20 kHz
3
1.5
1.6
Power efficiency (L/min-W)
0.0012 0.0010 0.0008 0.0006 0.0004 0.0002 0.0000 1
2
3
4
Plasma type
Note: 1Gliding Arc Plasma (this experiment), 2Plate DBD (Lie et al.), 3Tube DBD (Wang et al.), 4RF plasma (Hsieh et al.)
Figure 4. Power efficiency comparison among non-thermal plasmas
4
80
CO (experiment) O2 (experiment)
70
CO (simulation) O2 (simulation)
Selectivity (%)
60 50 40 30 20 10 0 0.0
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
Gas flow rate (L/min)
Figure 5. Product selectivity of CO2 conversion into CO and O2.
5
1.6
O
+
C
+
+
CO
CO
CO
2
O
(6 .1 ), C O
O
2
2
CO
2
+
2
(11 )
(1 .2 ), O (1 .4 ) 2
C
+
(5 x1 0 - 3)
O
+
(5 x1 0
- 3)
O
+
(5 x1 0 - 3)
CO
+
2
CO
(1 .4 )
O 3 (4 x1 0 - 15) O 2 (7 .5 x1 0 - 47)
O
2
+
(6 .1 ), C O
+
(1 .2 )
Note:
1.
O
CO
2
C
O (1 .2 x1 0 - 49) CO
CO
+
(1 .2 x1 0 - 44) e (2 .5 )
C
CO
(10 )
e (4 x1 0 4)
CO
O
(4 .5 )
C 2
+
CO
(1 1 ), O +
+
(4 .5 ), e
2
(1 0 - 3)
CO
(1 0 )
the values of reaction rate coefficient are in brackets and the dimension is cm3s-1
Figure 6. Diagram of CO balance formation and conversion reactions.
6
3
O
CO
CO
CO
2
3
O
+
-
3 2
CO
(4 x1 0 - 15), e (7 .5 x1 0
2
O 2 (6 x1 0 - 5)
e, C
+
e, O
+
(11 )
(4 .5 )
- 47)
e
+ e (1 )
CO
2
CO
2
+
O
O (1 .1 ) +
(4 .5 )
O (1 .2 x1 0 - 49), e O
e
1.
+
CO
C
e , O +( 4 .5 )
O
Note:
+
O
e
-
(1 0 - 3)
CO
CO
C
+
the values of reaction rate coefficient are in brackets and the dimension is cm3s-1
Figure 7. Diagram of CO2 balance formation and conversion reactions.
7
3
60 air, 2 plates air, 4 plates oxygen, 2 plates nitrogen, 2 plates pure CO2
Conversion (%)
50
40
30
20
10
0 0.00
0.05
0.10
0.15
0.20
0.25
[CO2]/[CO2+additive gas]
Figure 8. Effect of different additional gas and intial CO2 concentration on the conversion of CO2. Data was taken at gas flow rate of 2 L/min and power frequency of 20 kHz (Experimental air was atmospheric air; in case of experiment using air, the number of electrode plates has been varied. 2 plates mean 1 positive electrode and 1 negative electrode, 4 plates mean 2 positive electrodes and 2 negative electrodes.)
8
80 oxygen nitrogen pure CO2
CO selectivity (%)
60
40
20
0 0.00
0.05
0.10
0.15
0.20
0.25
[CO2]/[CO2+additive gas]
Figure 9. Effect of different additional gas and initial CO2 concentration on CO selectivity.
Data was taken at gas flow rate of 2 L/min and power frequency of 20 kHz.
9
40
40
(a)
0.3 mm 0.5 mm pure CO2
α=N2, β=20.8%
30
Conversion (%)
Conversion (%)
α=N2, β=9.3% α=N2, β=17%
30
20
10
α=air, β=20% pure CO2
20
10
0 0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
[H2O]/[CO2+H2O]
Note:
(b)
1.
β=
[ CO2 ] [N2 ]
0 0.00
0.05
0.10
0.15
0.20
0.25
[H2O]/[CO2+H2O+α]
in vol/vol dimension
Figure 10. Effect of additional water on CO2 conversion.
10
0.30
0.35
6
H2 selectivity (%)
5
4
3
2 β=9.3% β=17% β=20.8%
1
0 0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
[H2O]/[CO2+H2O+N2] Note:
1.
β=
[ CO2 ] [N2 ]
in vol/vol dimension
Figure 11. Effect of water concentration on hydrogen production. Data was taken at gas flow rate of 2 L/min and frequency of 20 kHz
11
CO
H 2O
2
MFC
a d d itiv e g a s
h e a te r MFC
P la s m a R e a c to r v e n t to a tm o s p h e r e
TC D G C S K C a rb o n
5 L ittre
b u b b le f lo w m e te r
w e t te s t m e te r
Figure 1. Schematic diagram of experimental set up
1
6000
0.45
Voltage waveform
Current waveform
0.30
Current (Ampere)
Voltage (Volt)
4000 2000 0 -2000
0.15 0.00 -0.15 -0.30
-4000
-0.45
-6000 -2e-5
-1e-5
0
1e-5
2e-5
-2e-5
-1e-5
Time (second)
0
Time (second)
Figure 2. Voltage and current waveforms
2
1e-5
2e-5
25
Conversion (%)
20
15
10
5
0 0.0
0.8
0.9
1.0
1.1
1.2
1.3
1.4
Gas flow rate (L/min)
Figure 3. Effect of gas flow rate on CO2 conversion. Data was taken at fixed power frequency 20 kHz
3
1.5
1.6
Power efficiency (L/min-W)
0.0012 0.0010 0.0008 0.0006 0.0004 0.0002 0.0000 1
2
3
4
Plasma type
Note: 1Gliding Arc Plasma (this experiment), 2Plate DBD (Lie et al.), 3Tube DBD (Wang et al.), 4RF plasma (Hsieh et al.)
Figure 4. Power efficiency comparison among non-thermal plasmas
4
80
CO (experiment) O2 (experiment)
70
CO (simulation) O2 (simulation)
Selectivity (%)
60 50 40 30 20 10 0 0.0
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
Gas flow rate (L/min)
Figure 5. Product selectivity of CO2 conversion into CO and O2.
5
1.6
O
+
C
+
+
CO
CO
CO
2
O
(6 .1 ), C O
O
2
2
CO
2
+
2
(11 )
(1 .2 ), O (1 .4 ) 2
C
+
(5 x1 0 - 3)
O
+
(5 x1 0
- 3)
O
+
(5 x1 0 - 3)
CO
+
2
CO
(1 .4 )
O 3 (4 x1 0 - 15) O 2 (7 .5 x1 0 - 47)
O
2
+
(6 .1 ), C O
+
(1 .2 )
Note:
1.
O
CO
2
C
O (1 .2 x1 0 - 49) CO
CO
+
(1 .2 x1 0 - 44) e (2 .5 )
C
CO
(10 )
e (4 x1 0 4)
CO
O
(4 .5 )
C 2
+
CO
(1 1 ), O +
+
(4 .5 ), e
2
(1 0 - 3)
CO
(1 0 )
the values of reaction rate coefficient are in brackets and the dimension is cm3s-1
Figure 6. Diagram of CO balance formation and conversion reactions.
6
3
O
CO
CO
CO
2
3
O
+
-
3 2
CO
(4 x1 0 - 15), e (7 .5 x1 0
2
O 2 (6 x1 0 - 5)
e, C
+
e, O
+
(11 )
(4 .5 )
- 47)
e
+ e (1 )
CO
2
CO
2
+
O
O (1 .1 ) +
(4 .5 )
O (1 .2 x1 0 - 49), e O
e
1.
+
CO
C
e , O +( 4 .5 )
O
Note:
+
O
e
-
(1 0 - 3)
CO
CO
C
+
the values of reaction rate coefficient are in brackets and the dimension is cm3s-1
Figure 7. Diagram of CO2 balance formation and conversion reactions.
7
3
60 air, 2 plates air, 4 plates oxygen, 2 plates nitrogen, 2 plates pure CO2
Conversion (%)
50
40
30
20
10
0 0.00
0.05
0.10
0.15
0.20
0.25
[CO2]/[CO2+additive gas]
Figure 8. Effect of different additional gas and intial CO2 concentration on the conversion of CO2. Data was taken at gas flow rate of 2 L/min and power frequency of 20 kHz (Experimental air was atmospheric air; in case of experiment using air, the number of electrode plates has been varied. 2 plates mean 1 positive electrode and 1 negative electrode, 4 plates mean 2 positive electrodes and 2 negative electrodes.)
8
80 oxygen nitrogen pure CO2
CO selectivity (%)
60
40
20
0 0.00
0.05
0.10
0.15
0.20
0.25
[CO2]/[CO2+additive gas]
Figure 9. Effect of different additional gas and initial CO2 concentration on CO selectivity.
Data was taken at gas flow rate of 2 L/min and power frequency of 20 kHz.
9
40
40
(a)
0.3 mm 0.5 mm pure CO2
α=N2, β=20.8%
30
Conversion (%)
Conversion (%)
α=N2, β=9.3% α=N2, β=17%
30
20
10
α=air, β=20% pure CO2
20
10
0 0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
[H2O]/[CO2+H2O]
Note:
(b)
1.
β=
[ CO2 ] [N2 ]
0 0.00
0.05
0.10
0.15
0.20
0.25
[H2O]/[CO2+H2O+α]
in vol/vol dimension
Figure 10. Effect of additional water on CO2 conversion.
10
0.30
0.35
6
H2 selectivity (%)
5
4
3
2 β=9.3% β=17% β=20.8%
1
0 0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
[H2O]/[CO2+H2O+N2] Note:
1.
β=
[ CO2 ] [N2 ]
in vol/vol dimension
Figure 11. Effect of water concentration on hydrogen production. Data was taken at gas flow rate of 2 L/min and frequency of 20 kHz
11
