Evonik and Siemens Commission Photosynthesis Pilot

24.09.2020 - Evonik and Siemens Energy have commissioned a pilot plant that uses carbon dioxide (CO2) and water to produce chemicals. The plant is the culmination of two years’ work under the Rheticus I and II research projects to develop a technically feasible foundation for artificial photosynthesis using a bioreactor and electrolyzers.

Located at Evonik’s site in Marl, in Germany’s northern Ruhr area, the plant uses artificial photosynthesis technology to produce specialty chemicals, such as butanol and hexanol, initially for research purposes. Other specialty chemicals are conceivable, the partners said, depending on the bacterial strain and conditions.

The plant’s facilities comprise a carbon monoxide (CO) electrolyzer developed by Siemens Energy, a water electrolyzer, and a 2,000- liter bioreactor based on Evonik’s knowhow.

In the electrolyzers, CO2 and water are converted into CO and hydrogen with electricity in a first step. The synthesis gas is then used by special microorganisms to yield chemicals for use in products such as specialty plastics or food supplements.

In the coming weeks, the companies will optimize the composition of the synthesis gas and the interaction between electrolysis and fermentation. In addition, they will set up a unit for processing the liquid from the bioreactor to obtain the pure chemicals.

The Rheticus projects are sponsored by the German Federal Ministry of Education and Research (BMBF) with total funds amounting to €6.3 million. They are a spin-off from Germany’s Copernicus projects, a huge initiative to transform the country’s energy system by 2025.

Rheticus II runs until 2021.


Author: Elaine Burridge, Freelance Journalist