Development and industrial demonstration of a structured Ni-AlOx honeycomb catalyst for CO2 methanation

The accelerating impacts of climate change require efficient carbon capture and utilization (CCU) pathways for hard-to-abate industries such as integrated steelworks. Catalytic methanation offers a promising technology, enabling the conversion of captured CO 2 and renewable hydrogen into synthetic natural gas while existing process infrastructure remains in place. In this work, methanation is investigated under real industrial conditions in an integrated steelworks, where hydrogen is supplied from a PEM electrolyser operating on the balancing electricity market, and CO 2 is recovered from power plant flue gases via amine scrubbing. For this purpose, a self-supporting structured γ-alumina-based honeycomb with a cell density of 350 cpsi was impregnated with nickel nitrate to achieve high nickel loadings of approximately 30 wt%. The developed catalyst was demonstrated in an actively cooled two-stage 20 kW SNG methanation unit under varying operating conditions with real gases. Across the investigated operating conditions, CO 2 conversions of 99.0 – 99.8 % were achieved, with methane concentrations of up to 95.0 vol% on a dry basis and residual CO 2 concentrations below 0.9 vol%. The remaining hydrogen concentrations ranged from 4.8 to 13.9 vol%, depending on the applied hydrogen surplus and operating conditions. Stable operation was demonstrated over more than 85 h of operation, while the two-stage configuration enabled high overall CO 2 conversion and product gas compositions suitable for injection into the natural gas grid. These findings highlight the potential of structured nickel-based honeycombs as a robust and scalable catalyst concept for industrial methanation within CCU applications, supporting its deployment across a broader range of hard-to-abate industrial sectors.