Researchers from the Karlsruhe Institute of Technology (KIT) have successfully produced renewable methane from a biomass-based synthesis gas mixture in their pilot plant for methanation using a new honeycomb catalyst. The quality of this synthetic natural gas (SNG) is comparable to that of fossil natural gas and can be used as fuel in cogeneration and heating plants as well as in cars or trucks.

Honeycomb catalyst.

The pilot plant was designed and tested by researchers of Karlsruhe Institute of Technology (KIT) and the Research Centre of the German Technical and Scientific Association for Gas and Water (DVGW).

Chemical energy carriers have a high energy density and are particularly attractive for the mobility sector.

—Felix Ortloff, Head of the Process Engineering group of the DVGW Research Centre at KIT’s Engler-Bunte Institute (EBI)

Biogas facilities produce renewable gas mainly by fermenting biological waste. In countries with a large forestry sector, such as Finland or Sweden, there is a high potential for the production of SNG from waste wood. A synthesis gas consisting mainly of hydrogen, carbon monoxide, and carbon dioxide is produced by biomass gasification. This mix can then be converted into high-quality methane by methanation.

Researchers of KIT’s Engler-Bunte Institute and the DVGW Research Center successfully tested a highly efficient methanation process for a period of several weeks in the city of Köping, Sweden.

The core components of the plant are honeycomb catalysts that were developed and optimized for use by the Catalytic Fuel Conversion group of the EBI Division of Fuel Chemistry and Technology headed by Siegfried Bajohr. Metallic nickel catalysts convert hydrogen and carbon monoxide and—in case of sufficient hydrogen supply, also carbon dioxide—into methane and water, Bajohr said.

The pilot plant of container design was coupled to a biomass gasifier that supplies the carbon-containing gases required for chemical reaction. Within this complex, KIT’s methanation plant reliably converted synthesis gas into methane for a period of several weeks. The synthetic methane produced was then applied as fuel in the natural gas vehicles of Swedish project partner Cortus AB.

The technology can also be applied to power-to-gas systems. In this case, water is split into hydrogen and oxygen by electrolysis using renewable electric energy. Then, the hydrogen reacts with carbon dioxide to synthetic methane.

The pilot plant now is on its way back to Karlsruhe where it will be integrated in the infrastructure of the Energy Lab 2.0 on KIT’s Campus North. The researchers want to further improve honeycomb methanation and optimize the catalysts for use in much larger facilities.