Hydrogen and Carbon Production via Methane Thermal Decomposition: Effects of Temperature and Residence Time

Methane thermal decomposition is a promising technology for producing CO2-free hydrogen. This study experimentally examines how temperature (1,000–1,400oC) and residence time affect methane decomposition in a ceramic tubular reactor. The results show that both the methane conversion rate and hydrogen yield increased with temperature, reaching approximately 95% and 45%, respectively, at 1,400oC. At lower temperatures (1,000–1,200oC), residence time had a significant impact, while at higher temperatures (1,300–1,400oC), temperature became the predominant factor. Additionally, the formation of C2 hydrocarbons, particularly acetylene (C2H2), increased as residence time decreased, negatively affecting both methane conversion and hydrogen yield. Analysis of the solid carbon by-products identified two distinct forms: amorphous, spherical carbon black particles and a semi-graphitic, crystalline carbon film. These findings provide essential data for optimizing the conditions of methane thermal decomposition.