Performance modeling and experimental validation of a thermally integrated micro-scale thermal partial oxidation reactor and flame-assisted fuel cell system

Abstract

Micro-tubular flame-assisted fuel cell (mT-FFC) studies generally focus on specific fuels, individual system components, or a limited range of operating conditions. This study combines system-level modeling with experimental validation of an integrated mT-FFC configuration utilizing a micro-scale thermal partial oxidation reformer. The modeling framework couples partial oxidation reforming, electrochemical conversion in the fuel cell, tail-gas combustion, and heat recovery, and performance is assessed with common fuels such as methane, propane, and n -butane. An experimental setup of the integrated system is operated with n -butane fuel to assess the feasibility of self-sustained operation under non-ideal conditions. A zero-dimensional equilibrium model is developed of the partial oxidation process at equivalence ratios of Φ = 1–5, total fuel/air flow rates of 200–400 mL/min, and fuel utilizations of 0.3–1.0. The model predicts the equilibrium mole fractions of H 2 , CO, H 2 O, and CO 2 , together with the reversible cell potential, electrical efficiency, and electrical power output under adiabatic conditions. Increasing Φ shifts the equilibrium composition from H 2 O and CO 2 toward the electrochemically active species H 2 and CO, while the reversible cell potential approaches a plateau under highly fuel-rich conditions. Electrical efficiency increases with fuel utilization and reaches a maximum at intermediate-to-high equivalence ratios before declining under richer conditions. The peak modeled efficiency for methane is approximately 43% at Φ ≈ 4 , flow rate = 400 mL/min and fuel utilization = 1.0 compared with approximately 38% for propane and 37% for n -butane. In the experimental portion of the study, the integrated n -butane prototype maintained electrochemical power generation during a 1.4 h constant-current test, although fluctuations in power density were observed. Together, the modeling and experimental results provide a system-level assessment of fuel-dependent performance and the practical feasibility of thermally integrated micro-scale thermal partial oxidation and mT-FFC operation.