Catalytic decomposition of ammonia in a membrane reactor

Collins, John P.; Way, J. Douglas

doi:10.1016/0376-7388(94)00138-3

Cited by 92 publications

(43 citation statements)

References 8 publications

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“…Any NH 3 remaining in the inlet stream to the PEMFC can potentially damage the Nafion TM polymer membrane so a robust separation method is required for the pre-purification of hydrogen [7]. Alternatively, an attractive process is the use of membrane reactor as reported [15,16].…”

Section: Hydrogen Production Via Ammonia Decompositionmentioning

confidence: 99%

H2 Production via Ammonia Decomposition Using Non-Noble Metal Catalysts: A Review

2016

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The wide-spread implementation of the so-called hydrogen economy is currently partially limited by an economically feasible way of storing hydrogen. In this context, ammonia has been commonly presented as a viable option for chemical storage due its high hydrogen content (17.6 wt%). However, its use as an energy carrier requires the development of catalytic systems capable of releasing hydrogen at adequate rates and conditions. At the moment, the most active catalytic systems for the decomposition of ammonia are based on ruthenium, however its cost and scarcity inhibit the wide scale use of these catalysts. This issue has triggered research on the development of alternative catalysts based on more sustainable systems using more readily available, non-noble metals mainly iron, cobalt and nickel as well as a series of transition metal carbides and nitrides and bimetallic systems, which are reviewed herein. There have been some promising cobaltand nickel-based catalysts reported for the decomposition of ammonia but metal dispersion needs to be increased in order to become more attractive candidates. Conversely, there seems to be less scope for improvement of iron-based catalysts and metal carbides and nitrides. The area with the most potential for improvement is with bimetallic catalysts, particularly those consisting of cobalt and molybdenum.

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Section: Hydrogen Production Via Ammonia Decompositionmentioning

confidence: 99%

H2 Production via Ammonia Decomposition Using Non-Noble Metal Catalysts: A Review

2016

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“…1) An extremely high efficiency was gained using the hydrogenpermeable membrane reactor; namely, a high level of ammonia conversion above 94% was achieved in the membrane reactor under the experimental conditions, while only a 53% ammonia conversion was obtained in a conventional type catalytic reactor. Transition metals such as nickel [2][3][4] and ruthenium 5) have been reported to show a high catalytic activity for ammonia decomposition, but they are easily deactivated by coexisting sulfur compounds, for example, the ammonia decomposition in a coke oven gas.…”

Section: Introductionmentioning

confidence: 95%

Ammonia Decomposition Catalyst with Resistance to Coexisting Sulfur Compounds

et al. 2005

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A cheap and disposal catalyst will be required for the decomposition of ammonia in the presence of sulfur compounds. The possibility of iron ore and red mud as the ammonia decomposition catalyst was investigated using pure or diluted ammonia containing hydrogen sulfide as a reactant. Among the catalysts tested, red mud had the highest catalytic activity for the ammonia decomposition in the presence of hydrogen sulfide. On the other hand, a relatively low conversion of ammonia was observed using a nickel-based commercial catalyst for the ammonia decomposition. The deactivation behavior of an iron ore catalyst caused by sulfur poisoning depended on the pretreatment atmosphere before the reaction; namely, the deactivation was observed for the H 2 pretreatment, while the high level of ammonia conversion remained constant for the CO pretreatment. From the X-ray diffraction pattern of the catalysts, the used iron ore catalyst pretreated in the CO atmosphere included FeC x , which was also included in the red mud that was active for the ammonia decomposition. FeC x may be responsible to the sulfur poisoning resistance.

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“…MgH 2 has a bulk density of 1.45 g/cm 3 and decomposes at 280 • C under high vacuum. The MgH 2 feedstock contained about 10% magnesium as the result of its manufacturing process.…”

Section: Methodsmentioning

confidence: 99%

“…The challenge remains in the rapid and efficient conversion of ammonia into hydrogen. Cracking ammonia to hydrogen and nitrogen is an endothermic reaction, which begins at temperatures of 450-500 • C [2,3]. However, the rate and extent of ammonia cracking in the existing processes are not satisfactory * Corresponding author.…”

Section: Introductionmentioning

confidence: 99%