Researchers of the German Karlsruhe Institute of Technology (KIT) succeeded in producing renewable methane from a biomass-based synthesis gas mixture in their pilot plant for honeycomb methanation. The quality of this synthetic natural gas (SNG) is comparable to that of fossil natural gas and can be used as fuel in cars or trucks, as well as in cogeneration and heating plants. The plant was designed and tested by researchers of KIT and the Research Centre of the German Technical and Scientific Association for Gas and Water (DVGW). The methanation process was tested in the city of Köping, Sweden.
Mobility and heat still are mainly based on fossil sources. For the future sustainable and environmentally compatible energy supply in these sectors, however, chemical energy carriers from renewable sources, such as biogas or SNG, are also suited, according to experts. “Chemical energy carriers have a high energy density and are particularly attractive for the mobility sector,” said Felix Ortloff, Head of the “Process Engineering” group of the DVGW Research Centre at KIT’s Engler-Bunte Institute (EBI).
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. By means of biomass gasification, a synthesis gas is produced, which mainly consists of hydrogen, carbon monoxide, and carbon dioxide. This mix can then be converted into high-quality methane by methanation.
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 (EBI ceb) headed by Siegfried Bajohr. “In a single-stage process, metallic nickel catalysts convert hydrogen and carbon monoxide and, in case of sufficient hydrogen supply, also carbon dioxide into methane and water,” explained Siegfried Bajohr.
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 our Swedish project partner Cortus AB,” Bajohr added.
“Apart from use in natural gas vehicles, methane can also be fed into the existing European natural gas infrastructure,” said Ortloff. “Moreover, the technology can also be applied in the power-to-gas context.”
After operation in Sweden, the pilot plant returned to Karlsruhe. “Our plant is characterized by a highly compact design and, hence, high mobility,” Ortloff informed. “When installed in a cargo container, it can be tested anywhere at remote biogas facilities, in rural areas, or in combination with other CO2 sources that might be relevant in the future, such as various industrial processes.”