Pilot-plant experimental tests and kinetic model validation of Ru-based catalytic methanation: assessment of operating pressure and filler material on carbon conversion

The production of synthetic methane is crucial for the energy transition in hard-to-electrify industries. This study assesses the reactor filler (Al₂O₃ and SiC) and operating pressure (1 and 4 bar) effects on methane performance of a commercial Ru-Al₂O₃ catalyst. Three catalytic methanation parameters are tested over a wide range: temperatures (200–450 °C), gas hourly space velocities (8000–120,000 h⁻¹), and H₂/CO₂ molar ratios (3.5–5.5). Experiments are conducted in two pilot plants located at the Universidad de Zaragoza and the Silesian University of Technology. Results demonstrate a high level of reproducibility between the two pilot plants, using Al₂O₃ filler at 1 bar. Additionally, a kinetic model is validated with experimental measurements, showing an error margin of ±5 % between the model and experimental data. Regarding the effects of operational pressure and reactor filler, the best carbon conversion results are obtained with Al₂O₃ filler at 4 bar (up to 98 %). For both reactors, a 5 % reduction in carbon conversion is observed at 450 °C for SiC filler. Methane selectivity remains above 99 % in all cases, except for SiC filler at 1 bar (90 %). However, SiC filler shows better thermal diffusion, facilitating operational control.