Two-dimensional mechanistic Solid Oxide Fuel Cell model with revised detailed methane reforming mechanism

A revised mechanistic SOFC model is presented with two main important modifications compared to the current state-of-the-art mechanistic SOFC models: 1) current models are all developed based on the “CH4 adsorption mechanism”; this is one of the most critical reactions but studies have indicated that CH4 adsorbed dissociatively on nickel, which is considered in the present revised model; and 2) kinetic data in the current models are fitted, in particular those for critical reactions such as CH4 cracking, CO and CO2 surface reactions; in the present work, the activation energies for those reactions are taken from DFT calculations, while the pre-exponential factors are still fitted to experimental data. The results show that carbon distribution predicted by the revised model fits better the experimental observations reported in the literature and thus the proposed revised model represents a more realistic SOFC model operating with CH4 or CO fuel gas. Furthermore, the revised model was used to investigate the distributions of gas/surface species concentration and temperature effects under humidified CH4. The results show that Ni surface is covered mainly by H(s) and CO(s) where the electrochemical reactions take place, whereas there is a very high coverage of C(s) where electrochemical reactions are absent.