Use of gasification syngas in SOFC: Impact of real tar on anode materials

Lorente, E.; Millán, Marcos; Brandon, Nigel P.

doi:10.1016/j.ijhydene.2011.11.047

Cited by 93 publications

(51 citation statements)

References 45 publications

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“…11 Many researchers have investigated the impact of different fuels with carbon contents, both experimentally and numerically, and demonstrated their degrading effect on the cell performance and the cell microstructure. 3,[11][12][13][14][15][16][17][18][19] Based on 3,7,18,[20][21][22] operating z E-mail: vanja.subotic@tugraz.at temperature defines the structure of the carbon formed. High operating temperatures (higher than 600…”

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confidence: 99%

Strategy for Carbon Gasification from Porous Ni-YSZ Anodes of Industrial-Sized ASC-SOFCs and Effects of Carbon Growth

Subotić

Schluckner

Stöckl

et al. 2016

J. Electrochem. Soc.

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Auxiliary power units (APUs) running on carbon-containing fuels provide solutions for high-efficient power supply and emission reduction. In order to ensure safe operation, unwanted degradation caused by carbon depositions should be avoided or controlled. Early detection allows trigerring of counteractions and avoids rapid deterioration of the cell performance as well as mechanical degradation of the cell microstructure and it is presented here. This study also shows that carbon does not only block the active catalyst sites and porous gas channels thus deteriorating the cell performance, but massive carbon depositions lead to destruction of the lattice YSZ-structure. In order to prolong the lifetime of the investigated cells, carbon-dioxide is tested as a possible agent for gasification of deposited carbon. Supplying with CO 2 gasifies carbon to carbon-monoxide, but experimental investigations show further degradation of the cell performance and a reduced methane conversion rate. A method, which represents a combination of CO 2 fed to the anode and an overvoltage applied to the cell, enabled complete performance regeneration in a cell-protecting manner. Solid oxide fuel cells are high-efficient devices, which convert the chemical energy of gaseous fuels directly into electrical energy without additional conversion steps. The heat losses occurring during the operation at temperatures between 600-1000• C can be used as a high-quality heat energy. SOFCs offer a great fuel flexibility and compared to other fuel cell types they can internally reform hydrocarbons. Internal conversion of carbon-containing fuels over nickel as the most widely used catalyst tends to promote carbonaceous deposits on the anode surface as well as inside the anode, causing deactivation of the fuel cells.1-3 The usage of other alternative materials such as Cu-, Gdand Sm-stabilized ceria-based materials or conducting oxides is possible to suppress carbon depositions, but Ni still offers a considerably better conductivity and electrocatalytic performance. 4-7Carbon deposition.-To date many researchers have investigated SOFC anode degradation. Khan et al.8 made a short review of Ni-YSZ degradation mechanisms, classifying these into four types: nickel coarsening, coking, redox instability and sulfur poisoning. A detailed analysis of challenges for nickel steam-reforming catalyst for industrial application can further be found in study from Sehestad.9 However, regarding operation of Ni-YSZ based SOFCs, if the cell is operated under expected conditions, which exclude sulfur in the fuel and the presence of oxygen on the anode side, redox instability and sulfur poisoning can be excluded as possible degradation phenomena. Nickel coarsening is a process where metal powder begins to sinter and small particles grow in size. It reduces the cell conductivity and worsens the cell performance. The sintering of nickel is also known to prone carbon formation, which requires prevention of this mechanism in order to reduce carbon build. 9 Coking can lead to an i...

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confidence: 99%

Strategy for Carbon Gasification from Porous Ni-YSZ Anodes of Industrial-Sized ASC-SOFCs and Effects of Carbon Growth

Subotić

Schluckner

Stöckl

et al. 2016

J. Electrochem. Soc.

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“…Therefore, toluene should prove to be a good approximation to the interactions between membranes and an actual tar mixture produced from biomass gasification [39,40]. A point of interest here is that the effect of single-ring aromatics tars on solid oxide fuel cell anodes were found to represent an even more challenging problem than the actual tars [41]. Moreover, the choice of toluene avoids the handling and safety issues associated with naphthalene and benzene.…”

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confidence: 99%

Ultra-microporous membrane separation using toluene to simulate tar-containing gases

Deonarine

Smart

et al. 2017

Fuel Processing Technology

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This study investigates the performance of ultra-microporous cobalt oxide silica membranes for processing simulated gas streams containing toluene as a model tar compound in gasification. The performance of the membranes was initially investigated for He (simulating H 2 ), CO 2 , N 2 and Ar in a range of temperatures. Subsequently, toluene was added to a gas mixture containing He and tested to 2 simulate the effect of toluene as a tar compound in gasification. The membranes delivered molecular sieving features, showing activated transport as the permeation of the smaller molecular gas He increased with temperature whilst the permeation decreased for the other larger molecular gases. Prior to toluene exposure, He permeance increased by almost twofold from 3.6 × 10 -8 to 7.1 × 10 -8 mol m -2 s -1 Pa -1 as the temperature was raised from 50 to 200 °C. Under a feed gas containing 0.24 mol% toluene, He permeance decreased by an average value of 17%. Upon regeneration of the membrane by heat, He permeance was not fully recovered, a clear indication of tar fouling. A toluene balance calculation showed toluene being retained by the membrane.

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“…The hydrocracking mechanism over Ni catalyst occurs via the process of absorbing the C n H 2n species on a dual active site of the nickel catalyst followed by consistent a-scission of the C-C bonds. Herewith, the resulting C * species thereafter reacted with oxygen from dissociation absorbed steam to yield CO and H 2 [53][54][55][56].…”

Section: Catalytic and Non-catalytic Activitymentioning

confidence: 99%

Effect of Ni/Al₂O₃-SiO₂and Ni/Al₂O₃-SiO₂with K₂O Promoter Catalysts on H₂, CO and CH₄Concentration by CO₂Gasification ofRosa MultifloraBiomass

Tursunov¹,

Zubek²,

Dobrowolski³

et al. 2017

Oil & Gas Science and Technology - Rev. IFP Energies nouvel

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Use of gasification syngas in SOFC: Impact of real tar on anode materials

Cited by 93 publications

References 45 publications

Strategy for Carbon Gasification from Porous Ni-YSZ Anodes of Industrial-Sized ASC-SOFCs and Effects of Carbon Growth

Strategy for Carbon Gasification from Porous Ni-YSZ Anodes of Industrial-Sized ASC-SOFCs and Effects of Carbon Growth

Ultra-microporous membrane separation using toluene to simulate tar-containing gases

Effect of Ni/Al₂O₃-SiO₂and Ni/Al₂O₃-SiO₂with K₂O Promoter Catalysts on H₂, CO and CH₄Concentration by CO₂Gasification ofRosa MultifloraBiomass

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Use of gasification syngas in SOFC: Impact of real tar on anode materials

Cited by 93 publications

References 45 publications

Strategy for Carbon Gasification from Porous Ni-YSZ Anodes of Industrial-Sized ASC-SOFCs and Effects of Carbon Growth

Strategy for Carbon Gasification from Porous Ni-YSZ Anodes of Industrial-Sized ASC-SOFCs and Effects of Carbon Growth

Ultra-microporous membrane separation using toluene to simulate tar-containing gases

Effect of Ni/Al2O3-SiO2and Ni/Al2O3-SiO2with K2O Promoter Catalysts on H2, CO and CH4Concentration by CO2Gasification ofRosa MultifloraBiomass

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Effect of Ni/Al₂O₃-SiO₂and Ni/Al₂O₃-SiO₂with K₂O Promoter Catalysts on H₂, CO and CH₄Concentration by CO₂Gasification ofRosa MultifloraBiomass