Stack Modelling of a Molten Carbonate Fuel Cell (MCFC)

Pfafferodt, Matthias; Heidebrecht, Peter; Sundmacher, Kai

doi:10.1002/fuce.200900174

Cited by 11 publications

(6 citation statements)

References 21 publications

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“…A C C E P T E D ACCEPTED MANUSCRIPT 5 the various cells. This behavior, already shown in previous studies conducted on different cell and stack geometries [4,12,15,16] and confirmed by the experimental analysis, is responsible for undesired behaviors: efficiencies or power densities lower than expected, due to larger resistances, and reduced lifetime, due to high temperatures and large temperature gradients. Possible design changes that allows one to reduce gradients at cell level have been examined in [17].…”

supporting

confidence: 82%

“…where n r is the unit vector perpendicular to the surface, i r the current, n e the number of electrons involved in the electrochemical reaction of the i-th species and F the Faraday's constant. A convective flow condition (12) is assumed on the outlet sections, while mass fluxes are set to zero at the solid walls. The continuity is imposed at the electrode/outlet channel interfaces.…”

Section: Mcfc Stack Geometry and Modelmentioning

confidence: 99%

“…The full 3D analysis is usually adopted for planar structures [9], sometimes using a coarse mesh. Other possible approaches in the case of stack modeling are based on repeated cells with proper boundary conditions to account for the position within the stack [11], on model reduction (2D) [10] and on quasi-3D models obtained through 1D [3], 2D [12] or network models [13] with proper inputs from parallel layers. This paper aims to investigate possible improvements that can be achieved by introducing design changes at stack level.…”

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confidence: 99%

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Design improvement of circular molten carbonate fuel cell stack through CFD Analysis

Verda

Sciacovelli

2011

Applied Thermal Engineering

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Molten carbonate fuel cell (MCFC) is a promising technology for distributed power generation. The core of a MCFC power generation unit is the stack, where various fuel cells are connected together in series and parallel in order to obtain the desired voltage and power. Stack geometry and configuration are major engineering topics, as inhomogeneous temperature or mass fractions cause inefficient performances of the fuel cells, as efficiency and power smaller than the expected and shorter lifetime. A detailed model is a useful tool to improve stack performances, through design improvements. In this paper, a 3D model of a stack composed of 15 circular MCFC, considering heat, mass and current transfer as well as chemical and electrochemical reactions is presented. The model validation is conducted using some preliminary experimental data obtained for a MCFC stack developed in the Fabbricazioni Nucleari laboratories. These results are examined in order to improve the stack configuration. It is shown that power density may be increased of about 20% through double side feeding. In addition, the average temperature gradients in the axial direction are reduced of more than 70%. Significant reductions in the temperature gradients, especially in transversal direction, can be achieved by adjusting the mass flow rate of cathodic gas supplied to the various cells. NOMENCLATUREEffective diffusion coefficient (m 2 s -1 )Mass diffusion coefficient (m 2 s -1 ) Apparent activation energy (K -1 ) Faraday constant (96487 C mol -1 ) Specific enthalpy (J kg -1 ) M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 4 Viscosity (m s -2 ) Density (kg m -3 ) Electric conductivity (Ω -1 m -1 ) Tortuosity Mass fraction of species i

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supporting

confidence: 82%

Section: Mcfc Stack Geometry and Modelmentioning

confidence: 99%

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confidence: 99%

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Design improvement of circular molten carbonate fuel cell stack through CFD Analysis

Verda

Sciacovelli

2011

Applied Thermal Engineering

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“…Thereby, endothermic reforming can be used as a very efficient “reactive cooling” mechanism for removal of the heat being released in the strongly exothermic electrochemical oxidation of hydrogen and carbon monoxide. Important challenges in designing this highly integrated system are (1) optimization of the spatial distribution of the reforming catalyst to attain an almost-homogeneous temperature field within the entire MCFC stack, − (2) monitoring of the three-dimensional (3D) temperature field by means of model-based observers, (3) optimization of the electrode pore size distribution to stabilize the spatial distribution of the electrolyte during operation, (4) improving the thermocycling of the stack, (5) improving the material stability and lifetime of the entire stack, and (6) reducing costs via the introduction of mass production methods.…”

Section: Functional Layers Single Cells and Stacksmentioning

confidence: 99%

Fuel Cell Engineering: Toward the Design of Efficient Electrochemical Power Plants

Sundmacher

2010

Ind. Eng. Chem. Res.

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Fuel cells are electrochemical membrane reactors that are able to convert chemically stored energy directly to electrical energy at high thermodynamic efficiencies. The present paper summarizes the current status and the future needs in fuel cell science and engineering. In the first part, possible primary fuels, alternative fuel processing pathways, and conceptual design aspects of fuel cell systems are discussed. In the second part, important trends in the development of functional materials for the preparation of stable high-performance fuel cells with extended longevity are presented. Thereby, different types of fuel cells are discussed, namely, enzymatic fuel cells (EFCs), alkaline fuel cells (AFCs), polymer electrolyte fuel cells (PEFCs), direct methanol fuel cells (DMFCs), direct ethanol fuel cells (DEFCs), phosphoric acid fuel cells (PAFCs), molten carbonate fuel cells (MCFCs), and solid oxide fuel cells (SOFCs).

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“…Various studies on the modeling of MCFCs have been performed. The complexity of the studied models ranges from simple and brief models to more complex 3-dimensional models of fuel cells [3]. Haghighat et al [4] analyzed a hybrid MCFC and a gas turbine unit by an external reforming reaction from an economical, technical, environmental, and optimization point of view.…”

Section: Introductionmentioning

confidence: 99%

Development of an Integrated Structure for the Tri-Generation of Power, Liquid Carbon Dioxide, and Medium Pressure Steam Using a Molten Carbonate Fuel Cell, a Dual Pressure Linde-Hampson Liquefaction Plant, and a Heat Recovery Steam Generator

Ghorbani

2021

Sustainability

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Due to the increase in energy consumption and energy prices, the reduction in fossil fuel resources, and increasing concerns about global warming and environmental issues, it is necessary to develop more efficient energy conversion systems with low environmental impacts. Utilizing fuel cells in the combined process is a method of refrigeration and electricity simultaneous production with a high efficiency and low pollution. In this study, a combined process for the tri-generation of electricity, medium pressure steam, and liquid carbon dioxide by utilizing a molten carbonate fuel cell, a dual pressure Linde-Hampson liquefaction plant and a heat recovery steam generator is developed. This combined process produces 65.53 MW of electricity, 27.8 kg/s of medium pressure steam, and 142.9 kg/s of liquid carbon dioxide. One of the methods of long-term energy storage involves the use of a carbon dioxide liquefaction system. Some of the generated electricity is used in industrial and residential areas and the rest is used for storage as liquid carbon dioxide. Liquid carbon dioxide can be used for peak shavings in buildings. The waste heat from the Linde-Hampson liquefaction plant is used to produce the fuel cell inlet steam. Moreover, the exhaust heat of the fuel cell and gas turbine would be used to produce the medium pressure steam. The total efficiency of this combined process and the coefficient of performance of the refrigeration plant are 82.21% and 1.866, respectively. The exergy analysis of this combined process reveals that the exergy efficiency and the total exergy destruction are 73.18% and 102.7 MW, respectively. The highest rate of exergy destruction in the hybrid process equipment belongs to the fuel cell (37.72%), the HX6 heat exchanger (8.036%), and the HX7 heat exchanger (6.578%). The results of the sensitivity analysis show that an increase in the exit pressure of the V1 valve by 13.33% would result in an increase in the refrigeration energy by 2.151% and a reduction in the refrigeration cycle performance by 9.654%. Moreover, by increasing the inlet fuel to the fuel cell, the thermal efficiency of the whole combined process rises by 18.09%, and the whole exergy efficiency declines by 12.95%.

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Stack Modelling of a Molten Carbonate Fuel Cell (MCFC)

Cited by 11 publications

References 21 publications

Design improvement of circular molten carbonate fuel cell stack through CFD Analysis

Design improvement of circular molten carbonate fuel cell stack through CFD Analysis

Fuel Cell Engineering: Toward the Design of Efficient Electrochemical Power Plants

Development of an Integrated Structure for the Tri-Generation of Power, Liquid Carbon Dioxide, and Medium Pressure Steam Using a Molten Carbonate Fuel Cell, a Dual Pressure Linde-Hampson Liquefaction Plant, and a Heat Recovery Steam Generator

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