CFD modeling of a biogas fuelled SOFC

Vakouftsi, E.; Marnellos, George; Athanasiou, C.; Coutelieris, Frank A.

doi:10.1016/j.ssi.2010.05.051

Cited by 53 publications

(40 citation statements)

References 28 publications

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“…It can be seen that CH 4 to CO 2 ratio of 30:20 gives the highest current for any given voltage. However, this is contrary to the experimental findings of Goula et al [5] and the modeling study of Vakouftsi et al [12]. Equilibrium calculations without carbon deposition predicts highest H 2 yield for equimolar mixture of CH 4 and CO 2 ( Table 4).…”

Section: Resultscontrasting

confidence: 58%

“…The composition fluctuations considered in the above discussions are for CH 4 /CO 2 ratio between 1.4-1.7; however, at CH 4 /CO 2 = 1, the model predictions are in conflict with reports by other groups [5,12]. It has been reported in the literature that for fuel composed of CH 4 and CO 2 , the maximum power output is obtained for equimolar molar mixture of CH 4 and CO 2 .…”

Section: Resultsmentioning

confidence: 67%

“…The study essentially focused on validating the exit gas composition under different current loads and CO 2 /CH 4 ratios. In another study, Vakouftsi et al performed CFD analysis of biogas fueled SOFC to estimate the species distribution and current density profiles [12]. They concluded that an equimolar mixture of CO 2 and CH 4 diluted with H 2 O leads to improved performance compared to other CH 4 /CO 2 ratios.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Internal reforming of biogas in SOFC: a model based investigation

Janardhanan

2015

J Solid State Electrochem

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This paper presents a multiphysics model for the simulation of solid oxide fuel cell operating on biogas without external reforming. The model accounts for multicomponent species transport, heterogeneous reaction kinetics on Ni cermet anode, H 2 electrochemical oxidation, and charge transport in the cermet electrodes and electrolyte. The model uses only three adjustable parameters that are fitted against one set of experimental data and then kept constant throughout the study. The model predicted voltage fluctuations are in excellent agreement with experimental measurements reported in the literature. The model also reveals that the assumption of H 2 as the only electrochemically active species is probably inadequate to explain the behavior of cells operating directly on biogas. Thermodynamic analysis is further performed to support this claim made based on model predictions. The model results demonstrate that the thickness of electrochemically active layer is independent of fuel composition under fuel rich conditions, however, thins down as the fuel becomes more and more diluted.

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Section: Resultscontrasting

confidence: 58%

Section: Resultsmentioning

confidence: 67%

Section: Introductionmentioning

confidence: 99%

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Internal reforming of biogas in SOFC: a model based investigation

Janardhanan

2015

J Solid State Electrochem

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“…In seven further studies , Klein et al 2007, Nikooyeh et al 2008, da Silva et al 2009, Vakouftsi et al 2011, Nematollahi et al 2012, Trabold et al 2012, the same or slightly transformed definitions, as those in Equations (22), (24), and (26), were applied to determine values of the solid carbon activity, a[C k (s)]. The calculations were based on minimization of the Gibbs energy using either commercial software or thermodynamic data from literature.…”

Section: Published Models Of Deposition Equilibriummentioning

confidence: 99%

On thermodynamic equilibrium of carbon deposition from gaseous C-H-O mixtures: updating for nanotubes

Jaworski

Zakrzewska

Pianko‐Oprych

2017

Reviews in Chemical Engineering

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AbstractExtensive literature information on experimental thermodynamic data and theoretical analysis for depositing carbon in various crystallographic forms is examined, and a new three-phase diagram for carbon is proposed. The published methods of quantitative description of gas-solid carbon equilibrium conditions are critically evaluated for filamentous carbon. The standard chemical potential values are accepted only for purified single-walled and multi-walled carbon nanotubes (CNT). Series of C-H-O ternary diagrams are constructed with plots of boundary lines for carbon deposition either as graphite or nanotubes. The lines are computed for nine temperature levels from 200°C to 1000°C and for the total pressure of 1 bar and 10 bar. The diagram for graphite and 1 bar fully conforms to that in (Sasaki K, Teraoka Y. Equilibria in fuel cell gases II. The C-H-O ternary diagrams. J Electrochem Soc 2003b, 150: A885–A888). Allowing for CNTs in carbon deposition leads to significant lowering of the critical carbon content in the reformates in temperatures from 500°C upward with maximum shifting up the deposition boundary O/C values by about 17% and 28%, respectively, at 1 and 10 bar.

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“…[18] The use of synthetic or real biogas in SOFCs has not only been modeled in numerous publications, [19][20][21][22][23][24][25] but has also been investigated in experimental studies. [26][27][28][29][30][31][32][33][34][35][36][37] Most research work has been done with internal reforming systems.…”

Section: Introductionmentioning

confidence: 99%

Oxidative Dry‐Reforming of Biogas: Reactor Design and SOFC System Integration

et al. 2013

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Biogas is an attractive fuel for solid oxide fuel cell applications because of the high CO2 content. Its composition allows a high electrical efficiency without adding external water to the system. Because of the CO2 reforming reaction only a very small amount of air is needed for partial oxidation, which is why the process could be called oxidative dry‐reforming. Herein, this concept is demonstrated by a thermodynamic analysis of the process and experimental system and component results. In order to realize a high yield of electrical power from the SOFC stack, a large flow of chemical energy into the stack is needed. To achieve this goal the efficiency of the reforming process is essential. With optimized reforming conditions it is possible to increase the chemical energy content of the fuel by adding an ample amount of heat to the reforming step. To achieve this in practice, the necessary heat flow to the reformer has to be calculated for a given operating temperature. Based on these thermodynamic calculations a reactor was built and tested. After successful laboratory tests the reactor was integrated into an SOFC system, where the necessary heat for the reforming step was supplied by the afterburner. The results of the component tests were verified under system conditions. Based on this system concept a high value for the electrical efficiency (ηel>0.5) of the system was achieved.

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CFD modeling of a biogas fuelled SOFC

Cited by 53 publications

References 28 publications

Internal reforming of biogas in SOFC: a model based investigation

Internal reforming of biogas in SOFC: a model based investigation

On thermodynamic equilibrium of carbon deposition from gaseous C-H-O mixtures: updating for nanotubes

Oxidative Dry‐Reforming of Biogas: Reactor Design and SOFC System Integration

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