Thesis - Oztek_Muzaffer_T_200508_MA

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44.5º LaNi 5 + 47.31 %Al Intensity (arb. units) LaNi 5 + 12.00 %Al LaNi 5 + 4.74 %Al 20 30 40 50 60 70 80 2-Theta (deg.) Figure 42. XRD spectra of milled LaNi 5 containing Al. 82
4. CONCLUSIONS This study has been a contribution to the unexplored field of separation of hydrogen and helium mixtures. The study has concentrated on LaNi 5 as the separating agent. In the small scale DSC, it exhibited fast kinetics with H 2 at ambient temperatures and at about 5 atm of pressure. The presence of He negatively influenced these parameters in the small scale. The effect was reduced to a large extent by applying a thin platinum coating on LaNi 5 ; however, this approach would be costly due to the use of Pt in the large scale. The scaled up analyses of LaNi 5 and its derivatives were done with batch and continuous systems. The LaNi 5 in the batch system reacted rapidly with H 2 even in the presence of He, provided that the partial pressure of H 2 was high enough. The continuous U-tube reactor system was successful in producing pure He. However the full capacity of the LaNi 5 was not achieved therefore the efficiency was low. The low capacity was due to short residence time of the gaseous reactant in the reactor, with the used equipment. With the addition of flow control equipment, the residence time in the reactor can be increased and the continuous system can be a stronger candidate to be used at the Kennedy Space Center for the recovery of hydrogen and helium. The XRD analysis of LaNi 5 and LaNi 5 Al x suggested that, by ball milling, LaNi 4 Al could be produced. However, the extent of conversion was not quantified in this thesis. LaNi 4 Al, if it had formed, was shown by DSC analysis that, absorbed less H 2 than LaNi 5 . 83
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RECOVERY OF HYDROGEN AND HELIUM FRO
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ABSTRACT Waste streams of hydrogen
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I dedicate this work to my family m
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I also would like to cheer for my f
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2.2.2.1. Hydriding and Dehydriding
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LIST OF FIGURES Figure 1. Pressure-
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Figure 34. Pressure profiles under
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1. INTRODUCTION The focus of this s
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ecause of the difference in partial
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hydrides by dissolving large amount
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hydrogen storage alloy has a specif
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• Insensitivity to poisoning by i
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hydrogen capacity was not reproduci
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showed the lowest plateau pressure
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grain boundaries increases the tota
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These parameters are generally inte
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Figure 4. CaCu5-type P6/mmm structu
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In this study, the addition of Al t
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2. EXPERIMENTAL 2.1.Chemicals and R
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Figure 5. The high energy Spex 8000
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2.2.1.1. Hydriding and Dehydriding
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approximately 5 atm, and heating th
Page 45 and 46: determined by the start and end of
Page 47 and 48: 450 400 coating thickness (Å) 350
Page 49 and 50: 3. RESULTS AND DISCUSSIONS 3.1. Hyd
Page 51 and 52: DSC 111 heat flow/mW Exo 300 Figure
Page 53 and 54: The thermogram associated with the
Page 55 and 56: total time was broken into three 30
Page 57 and 58: The VTiNi sample was subjected to d
Page 59 and 60: solid solution of hydrogen rather t
Page 61 and 62: DSC 111 Heat Flow/mW 180 Exo Figure
Page 63 and 64: 100 rpm setting, the milling vial w
Page 65 and 66: BPR, 400 rpm, 5 minutes) did not re
Page 67 and 68: Table 1: Effects of various milling
Page 69 and 70: Due to the fast kinetics observed a
Page 71 and 72: The mole % Al after milling was les
Page 73 and 74: Figure 24: Percent hydrogen capacit
Page 75 and 76: the start of the heating period, wh
Page 77 and 78: However, it was noted that the part
Page 79 and 80: percent hydrogen was decreased. The
Page 81 and 82: 3.2.2.4. AuPd and Pt Coating on LaN
Page 83 and 84: 1.0 0.8 (a) (b) Wt. % H absorbed 0.
Page 85 and 86: After dehydriding by the sample, th
Page 87 and 88: 19 18 P (atm) 17 16 15 14 0.74 %Al
Page 89 and 90: GC output, arbitrary units 0 5 10 1
Page 91 and 92: sample was LaNi 5 . This may indica
Page 93 and 94: 30 min. 15 min. Intensity (arb. uni
Page 95: After milling the percentages of Al
Page 99 and 100: 16. Van-Vucht, J.H.N., Kuijpers, F.
Page 101 and 102: 47. Suryanarayana, C., Progress in
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Thesis - Oztek_Muzaffer_T_200508_MA

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