Biogas plants could produce diesel and kerosene in the future. To build a pilot plant, the research institutes Fraunhofer IKTS, TU Bergakademie Freiberg and TU Dresden have joined forces with the Saxon companies Ökotec-Anlagenbau, Sunfire and DBI Gas- und Umwelttechnik to form a development alliance. Ökotec-Anlagenbau made its existing biogas plant available.
The partners also installed a reformer, a Fischer-Tropsch reactor and an electrolyzer there. In the first step, the expanded plant feeds biogas and water vapor into the reformer, which produces synthesis gas - a mixture of hydrogen and carbon monoxide. The Fischer-Tropsch unit then converts this synthesis gas into methane, liquid hydrocarbons and wax. The methane is fed straight back into the process to heat the plant. What remains is a 50:50 ratio of wax and liquid products. The latter can then be further processed into synthetic diesel or kerosene in refineries. As an alternative and additional source for the synthesis gas, a container is docked with the aforementioned electrolyzer. This is switched on when there is little biogas available or when there is a particularly high supply of electricity due to peaks from solar or wind power plants. This electrolyzer breaks down water vapour and carbon dioxide into hydrogen and carbon monoxide, i.e. synthesis gas again, and also ensures a continuous supply to the Fischer-Tropsch synthesis plant, which works efficiently when enough synthesis gas is available. The German government plans to introduce mandatory blending quotas for electrically produced kerosene from 2026. Interest in e-kerosene could also come from paint and varnish manufacturers as well as the cosmetics and lubricants industries.
