Methane Pyrolysis in a Liquid Metal Bubble Column Reactor for CO2-Free Production of Hydrogen

Abstract

In light of the growing interest in hydrogen as an energy carrier and reducing agent, various industries, including the iron and steel sector, are considering the increased adoption of hydrogen. To meet the rising demand in energy-intensive industries, the production of hydrogen must be significantly expanded and further developed. However, current hydrogen production heavily relies on fossil-fuel-based methods, resulting in a considerable environmental burden, with approximately 10 tons of CO2 emissions per ton of hydrogen. To address this challenge, methane pyrolysis offers a promising approach for producing clean hydrogen with reduced CO2 emissions. This process involves converting methane (CH4) into hydrogen and solid carbon, significantly lowering the carbon footprint. This work aims to enhance and broaden the understanding of methane pyrolysis in a liquid metal bubble column reactor (LMBCR) by utilizing an expanded and improved experimental setup based on the reactor concept previously proposed by authors from Montanuniversitaet in 2022 and 2023. The focus is on investigating the process parameters’ temperature and methane input rate with regard to their impact on methane conversion. The liquid metal temperature exhibits a strong influence, increasing methane conversion from 35% at 1150 °C to 74% at 1250 °C. In contrast, the effect of the methane flow rate remains relatively small in the investigated range. Moreover, an investigation is conducted to assess the impact of carbon layers covering the surface of the liquid metal column. Additionally, a comparative analysis between the LMBCR and a blank tube reactor (BTR) is presented.