Behavior of anode-supported SOFCs under simulated syngases

Miao, He; Liu, Guanghui; Chen, Tao; He, Chao; Peng, Jun; Ye, Shuang; Wang, Wei Guo

doi:10.1007/s10008-014-2640-7

Cited by 7 publications

(5 citation statements)

References 24 publications

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“…This demonstrates that the degree of graphitization of the deposited carbon increases with the distance in the fuel flow direction. 60 Similarly, Figure 8c shows that the intensities of the two peaks of D-bands and G-bands also decrease significantly in the bulk of the anode support, analogous to reduction in peak intensity along anode thickness direction observed by Lee et al 61 Such tendencies imply that in the flow or diffusion directions of fuels, methanol was converted rapidly and carbon deposition occurred; with decrease of methanol concentration, carbon deposition was suppressed. The particles in the anode exhaust pipe were found to be carbon, and the I D /I G ratio was 1.67 (see Figure 8b).…”

Section: ■ Results and Discussionsupporting

confidence: 69%

“…The equilibrium compositions, obtained by thermodynamic calculations using the free energy minimization approach, are essential for the prediction about SOFC fed with hydrocarbon fuels. − Figure a shows the calculated results of the dehydrated exhaust gas compositions for diverse S/C ratios at 750 °C. When the S/C is between 1 and 2, the main reformate products of humidified methanol fuels are H 2 , CO, CO 2 , and H 2 O with a negligible amount of CH 4 , while no carbon is formed.…”

Section: Resultsmentioning

confidence: 96%

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Power Generation by Flat-Tube Solid Oxide Fuel Cells with Enhanced Internal Reforming of Methanol

Sang

Yang

et al. 2022

ACS Sustainable Chem. Eng.

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Methanol is a promising fuel for solid oxide fuel cells (SOFCs) because of its low cost and ease of storage and transportation. In this work, the performance and long-term durability of direct methanol flat-tube SOFCs are investigated under different steam/carbon (S/C) ratios. It is confirmed that the S/C ratio exhibits little influence on cell performance but strongly affects long-term stability. The cell is discharged stably under high S/C ratios of 1.5 and 1.2, while it fails abruptly under a low S/C ratio of 1 due to severe carbon deposition. Extra nickel/yttria stabilized zirconia (Ni/YSZ) catalyst is added into the anode channels to serve as a prereformer. With improved internal reforming, the methanol conversion rate is promoted to 95% under S/C = 1, higher than that without extra catalyst and most results reported in the literature, and carbon deposition within the anode is significantly suppressed. Thus, no performance degradation is observed for 300 h of discharge under S/C = 1. On the basis of the experimental and simulating results, the mechanism of methanol conversion within the flat-tube cells is discussed.

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Section: ■ Results and Discussionsupporting

confidence: 69%

Section: Resultsmentioning

confidence: 96%

Power Generation by Flat-Tube Solid Oxide Fuel Cells with Enhanced Internal Reforming of Methanol

Sang

Yang

et al. 2022

ACS Sustainable Chem. Eng.

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“…Since 𝐻 𝑂 and 𝐶𝑂 are produced only in the thin anode functional layer through electrochemical oxidization of fuels, which facilitates the reforming reactions of 𝐶𝐻 and water gas shift reaction, it is less likely for direct 𝐶𝐻 cracking (reaction (8)) to occur in the thin Ni-containing layers. Therefore, carbon could be produced only through the Boudouard reaction (9) and hydrogenation (10). When the concentrations of 𝐻 𝑂 and 𝐶𝑂 are relatively high, which is usually the case in the thin anode functional layer, the backward reactions of ( 9) and ( 10) would be favorited.…”

Section: Single-cell Performancesmentioning

confidence: 99%

“…However, the high catalytic activity of Ni can also lead to the direct cracking of hydrocarbon compounds at high temperatures and CO hydrogenation as well as Boudouard reaction, causing carbon deposition in the anode. The carbon deposition, in turn, will deactivate active reaction sites, restrict gas flow, and damage microstructures, overall leading to severe degradations in anode performance and long-term stability [5][6][7][8][9]. Therefore, the carbon deposition issue in Ni-cermet anode electrode of hydrocarbonfueled SOFCs has been a major barrier towards practical applications.…”

Section: Introductionmentioning

confidence: 99%

Fabrication and Characterization of Thin-Film SOFC Supported by Microchannel-Structured Zirconia Substrate for Direct Methane Operation

Lee

Gan

Yang

et al. 2021

Int. J. Petrol. Technol.

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Ni-cermet anode demonstrates excellent catalytic activity and electrical conductivity but suffers from carbon deposition issue. To utilize Ni-cermet anode while preventing carbon deposition, a synergic strategy is employed to design anode electrode. In particular, Zr is incorporated into Ce0.8Sm0.2O2-δ lattice to tailor oxygen storage and catalytic properties of Ni-Ce0.8-xSm0.2ZrxO2-δ anode for improving electrochemical oxidizations of various fuel species. An inert thick YSZ microtubular substrate with radially well-aligned microchannels open at the inner surface is used to support multi thin functional layers of solid oxide cell, i.e., Ni current collector, Ni-Ce0.8-xSm0.2ZrxO2-δ anode, YSZ/SDC electrolyte, and LSCF cathode. The thick YSZ substrate is able to inhibit the ratio of fuel to product gases in the thin anode functional layer, which favors the prevention of carbon buildup in the thin anode layer when synergistically combined with Ni-Ce0.8-xSm0.2ZrxO2-δ anode material. The microchannels embedded in the YSZ substrate can also avoid too much dilutions of the fuel in the anode functional layer. The cell is fabricated and tested with both hydrogen and methane as the fuel. A short-term test is conducted with methane as fuel and good stability is obtained. The fundamental mechanisms for the prevention of carbon buildup in anode functional layer are also discussed.

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“…The state-of-the-art Ni/YSZ anode fulfills most of the requirements related to catalysis and thus widely used in pure hydrogen feed. However, inherited poor redox stability of nickel [18] and carbon intolerance [19] make Ni/YSZ anodes less suitable for use in syngas. Recently ceria-based materials have gained considerable attention as possible alternative anodes for hydrocarbon feeds [20,21].…”

mentioning

confidence: 99%

Electrochemical Oxidation of Syngas on Nickel and Ceria Anodes

Tabish

Patel

Aravind

2017

Electrochimica Acta

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Fuel flexibility of solid oxide fuel cells enables the use of low cost and practical fuels like syngas. Understanding of the oxidation kinetics with syngas is essential for proper selection of anode material and its design optimization. Using nickel and ceria pattern anodes, we study the electrochemical oxidation of syngas in both dry and wet environments. In dry environment, the polarization resistance of CO oxidation drops drastically with the addition of small amounts of hydrogen to CO gas stream. In wet environment (4 % moisture), the polarization resistance of CO is only slightly higher than syngas and hydrogen. Observation in the first case is related to the hydrogen preferential oxidation whereas latter is a combined effect of water gas shift reaction and preferential oxidation of hydrogen. Kinetic modeling is also carried out to understand hydrogen and CO co-oxidation. Simulation suggests that CO, besides hydrogen, may also electrochemically oxidize depending upon its concentration in the syngas. At higher concentration, CO electrochemical oxidation may be non-negligible especially in case of ceria anodes.

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Behavior of anode-supported SOFCs under simulated syngases

Cited by 7 publications

References 24 publications

Power Generation by Flat-Tube Solid Oxide Fuel Cells with Enhanced Internal Reforming of Methanol

Power Generation by Flat-Tube Solid Oxide Fuel Cells with Enhanced Internal Reforming of Methanol

Fabrication and Characterization of Thin-Film SOFC Supported by Microchannel-Structured Zirconia Substrate for Direct Methane Operation

Electrochemical Oxidation of Syngas on Nickel and Ceria Anodes

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