Prediction of Solid Oxide Fuel Cell Power System Performance Through Multi-Level Modeling

Bessette, Norman; Wepfer, William J.

doi:10.1115/1.2835428

Cited by 7 publications

(4 citation statements)

References 3 publications

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“…Basic features of the model.-The present model is developed for a tubular SOFC 6,9,10 schematically shown in Fig. 1.…”

Section: Modeling Of a Tubular Sofcmentioning

confidence: 99%

“…The local value of emf, E, is related to the terminal voltage V t , which is equal to the difference of electric potential between the interconnect side end of the cathode and the opposite end of the half-cylindrical shell-shaped anode, E c and E a , the activation polarization V a , the concentration polarization V c , and the local ionic conduction rate through a unit area of the electrolyte, namely, the local ionic current density i, as follows where r e is the ionic resistance of the electrolyte and is given by the product of the temperature-dependent electrolyte ionic resistivity 9,13 e and its thickness ␦ e . Activation polarization is normally expressed by the well-known Butler-Volmer equation and is approximated often by the Tafel equation in the range of small ionic current of SOFCs.…”

Section: Modeling Of a Tubular Sofcmentioning

confidence: 99%

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Numerical Modeling and Performance Study of a Tubular SOFC

Suzuki

2004

J. Electrochem. Soc.

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A quasi-2D model was proposed and made available for numerical studies on the performance of a single tubular solid oxide fuel cell ͑SOFC͒ under practical operating conditions. The model takes account of the air and fuel flow velocity fields, ohmic and thermodynamic heat generation, convective heat-transfer, mass transfer of participating chemical species including the electrochemical processes, and the electric potential and electric current in the electrodes and electrolyte. Numerical computation was carried out to test the proposed model for a single unit cell having a specific geometry being operated at a few different thermal and composition conditions for the inlet fuel and air flows. Obtained numerical results show that the quasi-two-dimensional approximation adopted in the model to mitigate the computational cost effectively can work reasonably well. At low electric current density, the cell terminal voltage was overpredicted. In order to improve the model on this point, the simple treatment adopted for the activation and concentration polarization in the model must be replaced by a more sophisticated approach in future studies. Discussions were further given concerning the obtained results for the overall cell performance and the detailed features of the velocity, thermal, and mass-transfer fields in the cell in addition to the local electrochemical characteristics. It is suggested that the air flow convective heat-transfer is important as a cooling means and that overpotential due to concentration polarization is more serious for the cathode side than for the anode side. All the presented results including the electricity conversion efficiency were observed to agree reasonably well with the popularly accepted cell performance.Solid oxide fuel cells ͑SOFCs͒ use solid oxides such as yttriastabilized zirconia ͑YSZ͒ for the electrolyte. Solid oxides are oxygen-ion-conducting materials so that not only hydrogen but a variety of hydrocarbons and even carbon monoxide can be used in principle as fuel. The operation temperature level of an SOFC is 800-1000°C because the ion conductivity of these materials becomes high enough only at this high temperature. 1 The high operating temperature creates difficulties for production and operation of the cell, but SOFCs have some desirable points, for example, in that expensive catalysts are not required for the electrochemical reaction and the high temperature means that a gas turbine can be effectively combined with an SOFC in a hybrid manner to form a single unit for a self-sustainable distributed energy system. 2 For the hightemperature operation, thermal management of the cell becomes an important issue. The temperature of the cell must be kept high enough to maintain a reasonable level of the electrolyte ion conductivity, but generation of localized ''hot spots'' must be avoided. 3,4 To carry out the thermal management properly, detailed analysis of the phenomena occurring inside the SOFC is required. Thus, a good model must be established to consider the complicated...

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“…Basic features of the model.-The present model is developed for a tubular SOFC 6,9,10 schematically shown in Fig. 1.…”

Section: Modeling Of a Tubular Sofcmentioning

confidence: 99%

Section: Modeling Of a Tubular Sofcmentioning

confidence: 99%

Numerical Modeling and Performance Study of a Tubular SOFC

Suzuki

2004

J. Electrochem. Soc.

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“…There are two types of numerical simulations applied to SOFCs. One is for a single cell [15][16][17][18][19][20] and another for a stacked-cell module [21][22][23][24]. In this chapter, the former type of numerical simulation is treated and in particular description is given to a numerical model developed for a tubular SOFC including a case of IIR-T-SOFC based on the model for the cathode-supported tubular SOFC reported in [15,16].…”

Section: Introductionmentioning

confidence: 99%

Electrochemical and thermo-fluid modeling of a tubular solid oxide fuel cell with accompanying indirect internal fuel reforming

Suzuki¹,

Nishino²

2005

Transport Phenomena in Fuel Cells

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Development of fuel cells has been boosted by global and regional environmental issues. Among others, the solid oxide fuel cell (SOFC) has been drawing much attention as a unit for distributed energy generation. Numerical analysis is used as a powerful tool in research and development of fuel cells, especially of the SOFC for which important and necessary thermal management information has scarcely been supplied experimentally. A central issue for achieving maximum benefit from the numerical analysis is how to properly model the complex phenomena occurring in the fuel cells. This chapter presents a numerical model for a tubular SOFC including a case with indirect internal reforming. In this model, the velocity field in the air and fuel passages and heat and mass transfer in and around a tubular cell are calculated with a two-dimensional cylindrical coordinate system adopting the axisymmetric assumption. Internal reforming and electro-chemical reactions are both taken into account in the model. Electric potential field and electric current in the cell are also calculated simultaneously allowing their nonuniformity in the peripheral direction. A previously developed quasi-two-dimensional model was adopted to combine the assumed axisymmetry of velocity, heat and mass transfer fields and the peripheral nonuniformity of electric potential field and electric current. Details of those numerical procedures are described and examples of the calculated results are discussed. After presenting a few fundamental results, several strategies to reduce the maximum temperature and temperature gradient of the cell are examined for a case with indirect internal fuel reforming.

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“…Haynes' fuel cell program was initially designed for use with methane (CH4) Gas 4 . In order to simulate a transport reactor syn gas and integrate it with the fuel cell Program, southern company engineer Luke Rogers provided the transport reactor's actual performance outputs (table 4.2.1).…”

Section: Integration Of Haynes' Fuel Cell Program With Gasifier Systemsmentioning

confidence: 99%

Investigating the Integration of a Solid Oxide Fuel Cell and a Gas Turbine System With Coal Gasification Technologies

Plummer

Haynes

Wepfer

2003

Heat Transfer: Volume 1

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Solid oxide fuel cell (SOFC) technology incorporates electrochemical reactions that generate electricity and high quality heat. The coupling of this technology with gas turbine bottoming cycles, to form hybrid power systems, leads to high efficiency levels. The purpose of this study is to conceptually integrate the hybrid power system with existing and imminent coal gasification technologies through computer simulation. The gasification technologies considered for integration include the Kellogg Brown Root (KBR) Transport Reactor and Entrained Coal Gasification. Parametric studies were performed to assess the effect of changes in pertinent fuel cell stack process settings such as operating voltage, inverse equivalence ratio and fuel utilization will be varied. Power output, system efficiency and costs are the chosen dependent variables of interest. Coal gasification data and a proven SOFC model program are used to test the theoretical integration. Feasibility and economic comparisons between the new integrated system and existing conventional systems are also made.

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Prediction of Solid Oxide Fuel Cell Power System Performance Through Multi-Level Modeling

Cited by 7 publications

References 3 publications

Numerical Modeling and Performance Study of a Tubular SOFC

Numerical Modeling and Performance Study of a Tubular SOFC

Electrochemical and thermo-fluid modeling of a tubular solid oxide fuel cell with accompanying indirect internal fuel reforming

Investigating the Integration of a Solid Oxide Fuel Cell and a Gas Turbine System With Coal Gasification Technologies

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