Methods for Current Efficient CO2-Neutral Production of Synthetic Gas

Hydrogen generated by water electrolysis with electricity from renewable energy sources has the potential to be the sustainable energy carrier for the 21st century. However, the successful large-scale integration of electrolyzer systems into electrical grids with volatile energy generation requires performance improvements in energy efficiency as well as in partial load operation. This thesis presents research on the electrochemical characterization of a self-designed alkaline electrolyzer and investigates the influence of modified direct current profiles on overpotentials. The variable current forms are provided by a newly developed process current source structure that functions as a dynamic output voltage rectifier. Additionally, this work highlights the possibility of further processing the generated hydrogen to methane via low-pressure glow discharge plasmolysis. This process employs a ceramic ion conductor in order to extract oxygen ions directly from the plasma and thus, reduces the recombination rate of carbon monoxide and oxygen. The combined energy conversion systems result in a CO2-neutral approach of synthetic gas generation.

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Hydrogen generated by water electrolysis with electricity from renewable energy sources has the potential to be the sustainable energy carrier for the 21st century. However, the successful large-scale integration of electrolyzer systems into electrical grids with volatile energy generation requires performance improvements in energy efficiency as well as in partial load operation. This thesis presents research on the electrochemical characterization of a self-designed alkaline electrolyzer and investigates the influence of modified direct current profiles on overpotentials. The variable current forms are provided by a newly developed process current source structure that functions as a dynamic output voltage rectifier. Additionally, this work highlights the possibility of further processing the generated hydrogen to methane via low-pressure glow discharge plasmolysis. This process employs a ceramic ion conductor in order to extract oxygen ions directly from the plasma and thus, reduces the recombination rate of carbon monoxide and oxygen. The combined energy conversion systems result in a CO2-neutral approach of synthetic gas generation.