SyngasFerm: Fuels from waste gases

Only a small proportion of the carbon-rich waste gases from industry are recovered as electricity and heat or used for other purposes. The aim of the Fraunhofer project “SyngasFerm“ was to identify new ways of utilizing this unused carbon source and to produce both fuels and specialty chemicals from the waste gases.

The amount of waste gas generated in industry is gigantic. In order not to leave this carbon source unused, the Fraunhofer project “SyngasFerm“ is converting these carbon-containing waste gases into materials in order to develop other products from them. To this end, the gases are fermented into alcohols and acetone, which, in turn, can be catalytically converted into high-quality fuel components for diesel and even kerosene. The products produced in this way can be used as fuel as well as for the production of special chemicals, e.g. amines. Amines, for example, are used in plastics processing, the pharmaceutical industry and in the manufacture of surfactants and dyes. The synthesis route developed in the project not only closes cycles in the chemical industry. It also represents a sustainable alternative for the production of fuels and specialty chemicals to processes that use crude oil as a source of raw materials. In addition to waste gases from industry, syngas-like gas mixtures from domestic and industrial waste incineration can also be used for the developed process.

In the “SyngasFerm“ project, a process has been developed that allows fuels and special chemicals to be obtained from the carbon-containing waste gases from industry. Synthesis gas - a mixture of carbon monoxide, carbon dioxide, and hydrogen - is used as a carbon source for fermentation. Bacterial strains of the genus Clostridium convert the syngas either into short-chain alcohols, such as butanol and hexanol, or into acetone. The fermentation products still containing residual water are evaporated and combined in a continuous catalytic process to form an intermediate product consisting of longer alcohols and ketones. This intermediate product already meets the marine diesel standard and can be converted by means of hydrogenation, similar to fats and oils, into diesel fuel for vehicles and kerosene for aircraft. The intermediate product is then used to produce specialty chemicals that can already directly replace crude oil-based products. The process developed and patented in the project successfully produced kerosene and specialty chemicals on a laboratory scale.

• Fraunhofer Institut für Molekularbiologie und Angewandte Oekologie IME
• Fraunhofer Institut für Chemische Technologie