In the context of the growing interest in hydrogen as an energy carrier and reducing agent, numerous industries, including the iron and steel sector, are contemplating an increased adoption of hydrogen. To meet the escalating demand in energy-intensive industries, it becomes imperative to significantly expand and further develop hydrogen production. However, the present hydrogen production methods heavily rely on fossil fuels, resulting in a substantial environmental burden, with approximately 10 tons of CO₂ emissions per ton of hydrogen generated. [1], [2]

To address this challenge, methane pyrolysis has emerged as a promising approach to produce clean hydrogen with reduced CO₂ emissions. This process involves the dissociation of methane into hydrogen and solid carbon, leading to a substantial reduction in the carbon dioxide footprint associated with hydrogen production. [3], [4]

The Montanuniversitaet Leoben (Austria) is currently actively engaged in research concerning methane pyrolysis and the development of a liquid metal bubble column reactor (LMBCR) specifically dedicated to this purpose. While the resulting H₂-rich product gas from methane pyrolysis may have potential applications in various processes, such as iron ore reduction, the carbon product, on the other hand, has stricter requirements in terms of impurities, depending on its intended field of use. Many applications demand very low threshold values for impurities in the carbon product [5]. Therefore, the main objective of this study is to investigate the chemical properties of carbon produced via methane pyrolysis in an LMBCR concerning impurities and to propose process technological improvements to enhance the overall product quality.