AVT-Colloqium: Renewable Synthesis of chemical Feedstock and Specialties employing Electrolysis and anaerobic Fermentation

Wednesday, July 07th 2021, 5:30pm

 

On July 07th 2021 at 17:30 Dr. Günter Schmid from Siemens Energy Global GmbH & Co. KG, Erlangen, Germany will give a lecture with the title:

„Renewable Synthesis of chemical Feedstock and Specialties employing Electrolysis and anaerobic Fermentation“

After the lecture there will be the possibility to talk to each other in break-out rooms.

Online lecture via zoom

Meeting-ID: 931 9423 0950

Kenncode: 873731

Renewable Synthesis of chemical Feedstock and Specialties employing Electrolysis and anaerobic Fermentation

Profitable renewable synthesis of chemicals and fuels is a prerequisite for its implementation into current economics. Boundary conditions for the synthesis sequence are the availability of renewable energy in sufficient quantities and its intermittent character. Profitability is difficult when considering the low fossil energy carrier prices and the physical efficiency limitations of the processes.

In the presentation, two options employing electrochemical reduction of CO2 are discussed:

The closest to industrial application process consists of two major components: Firstly, electricity from wind or solar is stored by electrolysis into energy carriers like hydrogen (H2) or carbon monoxide (CO). Current density, Faradaic and electrical efficiency and endurance of this upstream process will be discussed. Secondly downstream, a flexible mixture of CO, CO2 and H2 is supplied to a multistep anaerobic fermentation process, whereas they are initially converted to acetic acid and ethanol with high carbon efficiency and thus almost without any undesired by-products. The todays economic value is obtained by further condensation of the C2 products to C4 and C6 special chemicals (carboxylates and alcohols). Eventually, finally scaled into the hundreds megawatt range the molecules can be used as fuels.

In the talk a potential solution is addressed by using a commercially available silver-based gas diffusion electrode (used in industrial-scale chlorine–alkaline electrolysis) as the cathode in the CO2 electrolyser. Electric current densities up to 300 mA cm² were demonstrated for more than 1,200 hours with continuous operation. Faradaic efficiency of the anaerobic fermentation processes was almost quantitative1. Evonik and Siemens have decided to bring the technology toward an industrial scale. The project is named Rheticus2. Generally, such an approach is called artificial or technical photosynthesis.