Thermo-electrochemical modeling of oxygen ion-conducting solid oxide fuel cells with internal steam reforming in the water-energy nexus

• Published in: Energy nexus Vol. 5; p. 100057
• Main Authors: Bafekr, Sajed Hadi, Chitsaz, Ata, Holagh, Shahriyar Ghazanfari
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 16.03.2022; Elsevier
• Subjects: anodes; carbon dioxide; cathodes; chemical equilibrium; chemical species; electric potential difference; electrochemistry; fuel cells; Gibbs free energy; Lagrange's method of undetermined multipliers; oxygen; Oxygen ion-conducting; Solid oxide fuel cell; steam; temperature; Thermo-electrochemical simulation; Thermo-electrochemical simulation; Gibbs free energy; Lagrange's method of undetermined multipliers; Solid oxide fuel cell; Oxygen ion-conducting
• ISSN: 2772-4271; 2772-4271
• DOI: 10.1016/j.nexus.2022.100057

•A solid oxide fuel cell is modeled using Lagrange's method of undetermined multipliers.•A mathematical model is developed in the EES software.•The SOFC simulations by Lagrange's method at a definite state shows an efficiency of 54.6% and output power of 158.3 kW.•With Lagrange method, the analysis of the MCFC stack can be done more easily•Methane is used as a fuel for molten carbonate fuel cell stack The precise estimation of chemical equilibrium state is highly crucial when simulating electrochemical and thermodynamic aspects of oxygen ion-conducting solid oxide fuel cells (SOFC). One way to determine the equilibrium state of an internal reforming solid oxide fuel cell system is to compute the total Gibbs free energy of the system (G) and then, adjust the molar amounts of each substance, subject to element balances, so as to minimize G. Multi-dimensional optimization algorithms can be used for this purpose. In this paper, a powerful analytical solution method called Lagrange's method of undetermined multipliers is used for estimating the chemical equilibrium state. The effects of each current density, reaction temperature and pressure of the stack, and fuel and carbon dioxide utilization ratios on the voltage losses and output voltage and power of the stack, efficiency, and molar portions of the exhaust chemical species in anode and cathode, are investigated. The solid oxide fuel cell stack simulations by Lagrange's method at a definite state shows an efficiency of 54.6% and output power of 158.3 kW. [Display omitted] .