Ammonia as efficient fuel for SOFC

Fuerte, A.; Valenzuela, Rita X.; Escudero, M.J.; Daza, L.

doi:10.1016/j.jpowsour.2008.11.037

Cited by 172 publications

(83 citation statements)

References 14 publications

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“…27 The experimental OCV essentially decreased with increasing temperature under both humidified hydrogen and ammonia supplied conditions. On the other hand, the theoretical OCV for the direct ammonia oxidation as in Eq.…”

Section: 12mentioning

confidence: 90%

Electrochemical and Catalytic Behaviors of Ni–YSZ Anode for the Direct Utilization of Ammonia Fuel in Solid Oxide Fuel Cells

Molouk

Okanishi

Muroyama

et al. 2015

J. Electrochem. Soc.

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In this study the electrochemical performances of Ni-YSZ anode in humidified H 2 , NH 3 and CH 4 fuels were compared under almost the same partial pressure of oxygen at 500-800 • C. The cell performance was significantly affected by fuel species and operating temperature. The single cell exhibited higher performance in wet NH 3 as compared with that in CH 4 , which was caused by the difference in the catalytic activity of anode for the hydrogen production in wet NH 3 and CH 4 . Thus, it was clarified that NH 3 is a preferable fuel rather than CH 4 for the direct use in SOFCs. Furthermore, the kinetics study on ammonia decomposition over Ni-YSZ anode was conducted at 600 • C. Although the ammonia decomposition increased with increasing ammonia concentration, the decomposition reduced in the presence of hydrogen in the reactant gas. Such a behavior was not confirmed at 850 • C. These results indicated the inhibition effect of hydrogen for ammonia decomposition, which will be the key factor for the design of anode and the operating condition setting. Nowadays one of the most important challenges is producing energy from clean, renewable, durable, efficient and economically feasible sources. Solid oxide fuel cells (SOFCs) meet these goals. Variety of fuels can be used without the external reforming process because of high operating temperature of SOFCs. [1][2][3] Hydrogen is an ideal energy carrier and water is the only product of its combustion. For the massive utilization of hydrogen, however, there are still some difficulties in production, transportation, storage, and safety control. 4,5 Therefore, it is important to use hydrogen containing chemicals such as methane, ethanol and ammonia as alternative fuels.Methane has been studied extensively as a fuel for direct internal reforming SOFCs due to higher energy density compared to hydrogen. In SOFCs, Ni-based cermet anodes such as Ni-YSZ are widely used because nickel is a good catalyst for methane steam reforming as well as electrochemical hydrogen oxidation. However, the low tolerance to carbon deposition of Ni-based cermets is the main obstacle for the direct use of methane. In most of cases, the excess amount of steam is added to the fuel gas to prevent the coke formation, leading to the reduction in the energy conversion efficiency. The development of alternative anodes such as copper-based and perovskite-based materials will be a fundamental solution to this matter. 6,7 At the current state, however, the catalytic activity of these anodes for methane steam reforming is not sufficiently high. [8][9][10] The cell performance is also insufficient for the practical application since this catalytic activity significantly affects the hydrogen concentration in the vicinity of anode. 11,12 Recently ammonia was proven as one of the promising hydrogen carriers for SOFCs because of following reasons; high energy density comparable to that of methane, 4 carbon free, ease in liquefaction at ambient temperature, low production cost, and ease in leakage detection. [13][14]...

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Section: 12mentioning

confidence: 90%

Electrochemical and Catalytic Behaviors of Ni–YSZ Anode for the Direct Utilization of Ammonia Fuel in Solid Oxide Fuel Cells

Molouk

Okanishi

Muroyama

et al. 2015

J. Electrochem. Soc.

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“…Biomass can be easily converted into methanol, ethanol, and synthesis gas (CO + H 2 ). Ammonia and methane can be obtained from biological sources or from waste in a sustainable manner and eventually hydrogen can also be produced from biomass using thermal or biological processes [2][3][4][5][6][7]. SOFC-gas turbine (SOFC-GT) systems offer an opportunity for using biomass to meet energy requirements with highest possible efficiency and hence least environmental impact.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Analysis of Solid Oxide Fuel Cell Gas Turbine Systems Operating with Various Biofuels

2012

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Solid oxide fuel cell–gas turbine (SOFC‐GT) systems provide a thermodynamically high efficiency alternative for power generation from biofuels. In this study biofuels namely methane, ethanol, methanol, hydrogen, and ammonia are evaluated exergetically with respect to their performance at system level and in system components like heat exchangers, fuel cell, gas turbine, combustor, compressor, and the stack. Further, the fuel cell losses are investigated in detail with respect to their dependence on operating parameters such as fuel utilization, Nernst voltage, etc. as well as fuel specific parameters like heat effects. It is found that the heat effects play a major role in setting up the flows in the system and hence, power levels attained in individual components. The per pass fuel utilization dictates the efficiency of the fuel cell itself, but the system efficiency is not entirely dependent on fuel cell efficiency alone, but depends on the split between the fuel cell and gas turbine powers which in turn depends highly on the nature of the fuel and its chemistry. Counter intuitively it is found that with recycle, the fuel cell efficiency of methane is less than that of hydrogen but the system efficiency of methane is higher.

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“…Hence there is scope for solid state ammonia stores both for ammonia-fed solid oxide fuel cells (SOFCs) at high temperature or via catalytic conversion of ammonia to hydrogen for use in polymer electrolyte membrane (PEM) FCs at lower temperature. Currently commercial liquid/gaseous ammonia is the predominant feed for high temperature systems [17][18][19][20], where most research efforts are focused on use of ammonia in SOFCs [21,22].…”

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confidence: 99%

Ammonia Uptake and Release in the MnX2–NH3 (X = Cl, Br) Systems and Structure of the Mn(NH3)nX2 (n = 6, 2) Ammines

et al. 2012

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Hexa-ammine complexes, Mn(NH 3 ) 6 X 2 (X = Cl, Br), have been synthesized by ammoniation of the corresponding transition metal halide and characterized by Powder X-ray diffraction (PXRD) and Raman spectroscopy. The hexa-ammine complexes are isostructural (Cubic, Fm-3m, Z = 4; a = 10.2742(6) Å and 10.527(1) Å for X = Cl, Br respectively). Temperature programmed desorption (TPD) demonstrated that ammonia release from Mn(NH 3 ) 6 X 2 complexes occurred in three stages corresponding to the release of 4, 1 and 1 NH 3 equivalents respectively. The chloride and bromide both exhibit a deammoniation onset temperature below 323 K. The di-ammoniates from the first desorption step were isolated during TPD measurements and their crystal structures determined by Rietveld refinement against PXRD data (X = Cl: orthorhombic Cmmm, a = 8.1991(9) Å, b = 8.2498(7) Å, c = 3.8212(4) Å, Z = 2; X = Br: orthorhombic Pbam, a = 6.0109(5) Å, b = 12.022(1) Å, c = 4.0230(2) Å, Z = 2).

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Ammonia as efficient fuel for SOFC

Cited by 172 publications

References 14 publications

Electrochemical and Catalytic Behaviors of Ni–YSZ Anode for the Direct Utilization of Ammonia Fuel in Solid Oxide Fuel Cells

Electrochemical and Catalytic Behaviors of Ni–YSZ Anode for the Direct Utilization of Ammonia Fuel in Solid Oxide Fuel Cells

Thermodynamic Analysis of Solid Oxide Fuel Cell Gas Turbine Systems Operating with Various Biofuels

Ammonia Uptake and Release in the MnX2–NH3 (X = Cl, Br) Systems and Structure of the Mn(NH3)nX2 (n = 6, 2) Ammines

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