Methane Pyrolysis Using Metal Beads for CO2-Free Turquoise Hydrogen Production

Abstract

The study investigates the catalytic effect of steel beads on methane pyrolysis within a tube reactor at atmospheric pressure. The SUJ2 steel beads serve a dual role as a catalyst and heat transfer material, maintaining the overall system temperature below 1000 °C during the pyrolysis reaction. The catalytic decomposition of methane using the metal beads was compared to that in a blank tube reactor, revealing the significant catalytic impact of the beads. Under optimal conditions, the highest average methane conversion of 77% was achieved at 900 °C with a flow rate of 2.5 standard cubic centimeters per minute (sccm). The metal beads demonstrated durability over extended operational hours and were evaluated for their recyclability and scale-up perspective. The high specific heat of the SUJ2 steel beads contributed to uniform temperature distribution, further improving the efficiency of the pyrolysis process. Successive pyrolysis cycles showed increased methane conversion, which was attributed to the formation of iron carbides. Catalyst regeneration through oxidative processes effectively restored and enhanced catalytic activity, leading to progressively higher methane conversions. This study highlights the practical viability of SUJ2 steel beads for methane pyrolysis, providing a cost-effective alternative to traditional catalysts and bed materials.