Financed by the Federal Ministry of Food and Agriculture (BMEL), this project is a joint research of the University of Hohenheim, State Institute of Agricultural Engineering and Bioenergy, the Leibniz Institute for Agricultural Engineering Potsdam-Bornim, Dep. Bioengineering – Microbial Systems Ecology, and the DVGW - Research Center at the Engler-Bunte-Institut (KIT).
In the course of the development of renewable energy in Germany, great storage capacities for electrical energy are needed that can only be provided by chemical energy carriers. For hydrogen, an infrastructure for storage, transport and distribution is missing. A much greater potential can be ascribed to the storage of synthetically produced methane, since it can be fed into the natural gas grid with almost no restrictions. A promising alternative to the energy demanding catalytic Sabatier process (transformation of hydrogen to methane) is the biotic methanation of hydrogen and carbon dioxide, either directly in the biogas plant or in a separate reactor. An important advantage of this approach is that the carbon dioxide produced in the biogas process can be converted almost completely to methane by hydrogenotrophic, methanogenic archaea. Thus, little effort is needed for the preparation for feeding into the natural gas grid. Furthermore, the (regeneratively) generated carbon dioxide can be used optimally.
In this joint project which is composed of three subprojects, the potential of biotic methanation in two-stage process is investigated. Processes that are susceptible to hydrogen like degradation of propionic acid, are located in an upstream reactor. Hydrogen is then added to a second reactor, which is initially only supplied with a nutrient rich liquid. In experimental investigations, several reactor designs will be tested (fixed bed, fully mixed, membrane) in detail and new process concepts will be developed. Special attention will be paid to the change of the biocoenoses.
In subproject 2 at the EBI, we investigate the chances and restrictions of the microbial methanation in membrane reactors. In an initial step, hydrogen and carbon dioxide will be provided through a membrane, on which a biofilm of hydrogenotrophic, methanogenic archaea is cultivated.