Internal dry reforming of methane in solid oxide fuel cells

Abstract

In the context of global efforts to reduce greenhouse gas emissions and combat extreme global warming, the direct dry reforming of methane reaction in solid oxide fuel cells presents a promising avenue for clean energy production. This study delves into the influence of temperature, gas composition, and current density on the kinetics of dry methane reforming in solid oxide fuel cells. Power Law and Langmuir-Hinshelwood kinetic models were proposed to highlight the impact of operating conditions on dry methane reforming reactions. Results revealed that the feed gas composition strongly affects methane conversion, with higher methane contents resulting in lower conversions. Increasing the CH4/CO2 ratio increases reaction rates, and the effect decreases at a ratio of 1.25. The changes in methane concentration on dry methane reforming reaction rate are more significant than those for carbon dioxide. However, increasing carbon dioxide concentration enhances methane conversion. The exothermic nature of CO2 adsorption suggests that the adsorption process is thermodynamically favourable in dry reforming, and the elevated temperatures generally improve reaction rates and methane conversion by removing carbon deposits and providing the energy needed to break down the chemical bonds in methane which facilitating its transformation. A higher current density significantly enhances the CO2 adsorption equilibrium constant and further increases methane conversion, highlighting the positive role of electrochemical reactions on dry methane reforming. This study aims to fill the knowledge gap regarding the influence of electrochemical reactions on dry methane reforming behaviours in solid oxide fuel cells, offering critical insights for advancing anode design, thus contributing to the development of solid oxide fuel cell technologies to address global warming and reduce greenhouse gas emissions.