Kinetic and electrochemical modelling of solid oxide stack in presence of methane

The transition to renewable energy sources requires innovative solutions to reduce greenhouse gas emissions and mitigate climate change. Solid oxide electrolysis technologies feature many advantages, such as high efficiency with available steam or waste heat, and co-electrolysis capability. Integrating them in Power-to-Liquid processes improves efficiency and costs. For further enhancements, methane, common in these processes, could be recycled to the electrolyser for reforming. Experimental work demonstrates methane reforming impact on stack behaviour, highlighting the deviation of Open Circuit Voltage (OCV) from expected thermodynamic values, motivating an electrochemical and kinetic model. A Langmuir-Hinshelwood-Hougen-Watson mechanism was considered to model methane reforming, considering adsorption, reaction, and desorption processes on nickel-based catalysts. After fitting with steam- and co-electrolysis data, the model was validated with methane-fed stack data at temperatures from 700°C to 800°C. Normalized Root Mean Square Error values were under 0.53% for polarisation curves, indicating accurate predictions of stack behaviour.