Charakterisierung von Kohlenstoff aus der Methanpyrolyse im Flüssigmetallreaktor

As a low-emission energy carrier, hydrogen plays a key role in the transformation of the energy system. However, its current production is still predominantly fossil and associated with significant greenhouse gas emissions. Methane pyrolysis is considered a promising bridging technology because it splits methane into hydrogen and solid carbon while avoiding direct CO2 emissions. Thermodynamically, pyrolysis requires only a fraction of the enthalpy of the reaction compared to electrolysis. This enables an efficient and climate-friendly route for hydrogen production. In addition to the substitution of existing applications, there is also the potential to open up new carbon markets, for example in the battery sector or the building materials sector. For a successful market launch, the carbon produced must meet specific properties and defined quality requirements, depending on the application. The present thesis investigates the carbon from methane pyrolysis in a liquid metal bubble column reactor with tin as the reaction medium. The aim is to remove the carbon from the reactor system as completely as possible and to evaluate its properties in a well-founded manner. For material characterization, scanning electron microscopy, Raman spectroscopy and elemental analysis are used. These methods are employed to determine morphology, structure, and purity. The results show that the efficiency of the discharge system has a significant influence on product quality. Scanning electron microscope examinations show pronounced metallic impurities, mainly tin from the melt and, in small proportions, iron. At the same time, sheet-like structures become visible, which indicate crystalline components. The Raman evaluation indicates amorphous particles with a disordered structure as well as crystalline components, but is subject to uncertainties due to sample pretreatment and curve fitting. Although homogeneity and carbon content can be moderately increased by sieving, the effect remains limited when the carbon structures are intimately adhered to metal impurities. A well-founded material use of carbon represents an essential lever for the economic efficiency of methane pyrolysis and requires in-depth investigations into structure-property relationships as well as process-integrated purification strategies.