CHAPTER 4 CONCLUSION AND FUTURE WORK
4.2 R ECOMMENDATION OF F UTURE W ORK
The future work of this study are suggested as followed:
1. To compare different mole ratio of ethanol and steam injected.
2. PAC reforming should study in detail and different catalyst should apply to PAC system.
3. The optical emission spectral analysis of gliding arc should be done to understand how the plasma assists injected fuel reform into hydrogen.
4. To compare different reforming fuel such as methane or propane reforming.
5. We shall develop gliding arc in tornado plasma which promises to have longer residence time.
34
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[29] Shiki, H., Motoki, J., Ito, Y., et al. ‘‘Development of split gliding arc for surface treatment of conductive material’’, THIN SOLID FILMS, Vol.516, No.11, pp.3684-3689, 2008.
[30] Sun, J., Qiu, X.P., Wu, F., and Zhu, W.T., ‘‘H2 from steam reforming of ethanol at low temperature over Ni/Y2O3, Ni/La2O3 and Ni/Al2O3 catalysts for fuel-cell application’’, Int. J. Hydrogen Energy , 30, 437-445, 2005.
[31] Vizcaino, A.J., Carrero, A., and Calles, J.A., ‘‘Hydrogen production by ethanol steam reforming over Cu–Ni supported catalysts’’, Int. J. Hydrogen Energy, 32, 1450-1461, 2007.
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40
S/C：Mole ratio with water and ethanol
Table 1.1 Properties of ethanol steam reforming with different nobel metal catalysts.
41
K(1)-Ni(21) 59(20hr) 93(20hr)
Na(1)-Ni(21) 55(20hr) 95(20hr)
Li(1)-Ni(21) 83(20hr) 91(20hr)
Cu(2)-Ni(14) SiO2
S/C：Mole ratio with water and ethanol
Table 1.2 P
roperties of ethanol steam reforming with different non-nobel metal catalysts.42
43
1. C: conversion rate 2. S: selectivity 3. E: efficiency
Pox*: Partial oxidation reaction. ATR**: Auto thermal reaction.
Steam***: Steam reforming reaction.
Table 1.3 Summary of important features, experiments and parameters for plasma and PAC reforming.
44
Author Phase Power generator Power input
Y. Kusano
et al.
(2008)
AC
Power supply (Generator 6030. SOFTAL Electronic
GmbH, Germany).
DC Power supply (Universal Voltronics, Inc.)
Input voltage: 10 kV
Pulse modulator (Kurita Seisakusho Co., Ltd., 6 kW)
Slide regulator (Matsunaga Seisakusho, S3-2413, 5.2
kVA)
High-voltage transformer (Kurita Seisakusho Co., Ltd.,
250/12 kV)
Input power: 300 W
Pulse frequency: 15-20 kHz
Pulse width: 1.6-2.8 μs
Table 1.4 Summary of plasma power input type.
45
Instrument Model Specifications
1
46 Cycle
10 100 300 500 700 1000
Absorption Power (W) Power
30 % 338.56 273.77 274.81 273.77 278.75 263.11 40 % 215.68 191.3 198.38 180.43 182.11 183.3
50 % 146.43 225.6 212.28 225.63 222.05 223.32
Table 3.1 The absorption power of gliding arc under 1.5 SLM air flow rate, C/O ratio: 0.7.
Cycle
10 100 300 500 700 1000
Absorption Power (W) Power
30 % 202.88 177.34 177.71 179.68 174.94 170.86
40 % 92.03 124.9 107.53 106.85 107.75 106.47
50 % 103.3 102.48 100.72 100.95 100.98 102.44
Table 3.2 The absorption power of gliding arc under air flow rate 1.5 SLM.
47
Table 3.3 The residence time versus reforming efficiency.
Table 3.4 The C/O ratio versus reforming efficiency.
48
Comparison among Catalyst, PAC, and Plasma only Reforming
Catalyst PAC Plasma only
Mass Error 5% 3% 7%
H2 57.04% 111.20% 42%
CO2 39.66% 34.48% 32%
CO 60.34% 65.52% 68%
Water 42.96% -11.20% 58%
Conversion
Rate 90.00% 100.00% 39%
Table 3.5 The Comparison among catalyst, PAC, and Plasma-alone reforming efficiency.
Catalyst PAC Plasma only
LHV per second (kJ/s) 5.84 7.26 1.63
Efficiency (%) 40% 58% 8%
Cost (NT) 0.119 0.120 0.071 Cost / LHV 0.020 0.016 0.043
Table 3.6 The efficiency and LHV of catalyst, PAC, and plasma-alone.
49
Figures
Figure 1.1 Sketch of the typical test arrangement for ethanol reformer (left) and the
SOFC (right) at CGET of NCTU.
Figure 1.2 The basic reaction of ethanol steam reforming [Vizcaino et al., 2007].
50
Figure 1.3 The comparison between different plasma reactors [G. Petipas, et al., 2007].
Figure 1.4 An energy diagram indicating the standard enthalpy (△H°) and free energy changes (△G°) in kJ/mol for the reactions in a renewable energy cycle operating between CO2
and biomass [L. D. Schmidt, et al., 2004].
51
Figure 1.5 Influence of electrode gap (a) and vertical distance between electrode throat and nozzle oulet (b) on n-butane and toluene decomposition rate [Z. Bo et al., 2007].
Figure 1.6. Typical arrangement of instrumentation for PAC system [Y. C. Yang et al., 2009].
52
Figure 2.1 The self-designed gliding arc reactor
Figure 2.2 The power supply (PVM500 plasma driver).
30 mm
Φ, electrode gap = 1.4 mm 30 mm
95 mm
53
Figure 2.3 The fuel feeding nozzle.
Figure 2.4 The MFC and the liquid pump.
MFC
Liquid Pump
54
Figure 2.5 The procedure of catalyst preparation.
55
Figure 2.6 Rogowski coil.
Figure 2.7 High-voltage probe.
56
Figure 2.8 Thermocouple.
Figure 2.9 Gas Chromatograph.
57
Figure 2.10 The Experimental instrumentation of PAC system.
58
Figure 3.1 The selectivity of hydrogen, water, carbon dioxide and carbon monoxide over furnace temperature.
Figure 3.2 The conversion rate, hydrogen and carbon dioxide selectivities over air flow rate.
59
Figure 3.3 Schematic of the electricscheme [A. Fridman et al., 2000].
Figure 3.4 (a) Current-total power of the gliding arc; (b) discharge length-voltage of the gliding arc in (a) [A. Fridman et al., 2000].
60
Figure 3.5 Image of gliding arc under power 30%, air flow rate constant at 1.5 SLM and (a) without and (b) with the ethanol-water solution at C/O ratio 0.7.
Figure 3.6 Image of gliding arc under power 40 %, air flow rate constant at 1.5 SLM and (a) without and (b) with the ethanol-water solution at C/O ratio 0.7.
61
Figure 3.7 Image of gliding arc under power 50 %, air flow rate constant at 1.5 SLM and (a) without and (b) with the ethanol-water solution at C/O ratio 0.7.
Figure 3.8 The arc column motion when plasma power input 50 %, 1.5 SLM air flow rate. (1200 frames per second)
62
Figure 3.9 The arc column motion when plasma power input 50 %, 1.5 SLM air flow rate. (1200 frames per second)
Figure 3.10 The arc column motion when plasma power input 50 %, 1.5 SLM air flow rate. (1200 frames per second)
63
Figure 3.11 Electrical properties for gliding arc when 30% applied power.
Figure 3.12 Electrical properties for gliding arc when 40% applied power.
64
Figure 3.13 Electrical properties for gliding arc when 50% applied power.
65
Figure 3.14 Conversion rate, SH2 and SCO2 versus air flow rate.
Figure 3.15 SH2, SH2O and SCH4 versus air flow rate.
66
Figure 3.16 SCO2, SCO and SCH4 versus air flow rate.
Figure 3.17 Conversion rate, SH2 and SCO2 versus C/O ratio.
67
Figure 3.18 SH2, SH2O and SCH4 versus C/O ratio.
Figure 3.19 SCO2, SCO and SCH4 versus C/O ratio.
68
Figure 3.20 Conversion rate, SH2 and SCO2 versus plasma power input.