Comparative performance analysis of a flat tube solid oxide fuel cell using different fuels

Thesis Type: Doctorate

Institution Of The Thesis: Gazi University, Fen Bilimleri Enstitüsü, Turkey

Thesis Supervisor: Mustafa İlbaş

Approval Date: 2025

Thesis Language: Turkish

Open Archive Collection: AVESIS Open Access Collection

Abstract:

Flat tubular solid oxide fuel cells (SOFCs) are increasingly prominent among high-temperature fuel cell technologies due to their high energy conversion efficiency and multi-fuel flexibility. This thesis evaluates the effects of key design and operational parameters-electrode porosity, support layer configuration, operating pressure, temperature, fuel composition, and fuel flow rate-on SOFC performance through a combination of numerical modeling and experimental investigation. Numerical analyses reveal that increasing the operating pressure from 1 atm to 5 atm enhances the peak power density by approximately 8-10%. Likewise, raising the operating temperature from 700 °C to 750 °C yields roughly a 14% increase in peak power density at the same current density, contributing to reduced kinetic losses. In fuel type comparisons, pure hydrogen feeding maintains about 18% higher power relative to syngas, demonstrating its advantage in diffusion-limited regimes. Additionally, maintaining an electrode porosity of 0.45 and a fuel flow rate in the 300-400 SCCM range substantially mitigates mass transfer losses. The anode-supported cell architecture was found to deliver the highest energy density, with ohmic losses approximately 10-15% lower than alternative support configurations. Experimental results showed strong agreement with model predictions. The findings underscore that optimizing operating conditions and microstructure in SOFC design has a direct and significant impact on performance, offering a concrete roadmap for the development of next-generation, large-scale systems.