Experimentelle Untersuchung der CO2-Abtrennung mittels einer elektrochemischen Durchflusszelle

In addition to conventional carbon capture technologies, alternative approaches are increasingly being investigated to reduce anthropogenic CO2 emissions and to enable more flexible and potentially more energy-efficient CO2 separation processes. Among the approaches intensively studied in recent years are electrochemical methods, in which the capture and release of CO2 are controlled by the application of electrical potentials, allowing for direct coupling to renewable energy sources. In these systems, CO2 capture is based on reversible electrochemical redox reactions that enable selective modulation of the CO2 binding capability. In this work, the capture of CO2 from the gas phase was investigated experimentally using an electrochemical flow cell. The focus was placed on a process-engineering-oriented evaluation of the electrochemical cell, which was operated with functionalized carbon-based electrodes incorporating anthraquinone derivatives and a highly concentrated aqueous electrolyte. In addition, a specifically adapted gas handling and measurement setup was implemented to monitor the CO2 concentration in the gas stream using non-dispersive infrared (NDIR) gas analysis. The results show that under reducing conditions CO2 could be removed from a gas stream, whereas oxidizing conditions led to a release of CO2. Increasing the CO2 inlet concentration to 2.5 vol% did not result in a proportional change in the measured CO2 signals. Furthermore, system-related influences such as electrode-induced side reactions, as well as limitations associated with the cell design and the experimental setup, were identified.