Catalytic Methane Decomposition for the Simultaneous Production of Hydrogen and Low Reactivity Biocarbon for the Metallurgic Industry

To reach agreed-on climate goals, it is necessary to develop new energy carriers and industrial materials that are carbon neutral. To combat global warming and keep Earth’s temperature below a 1.5 °C increase, some of these solutions need to be carbon negative. This study fulfills this criterion by producing clean hydrogen, and biocarbon, suitable for the metallurgic industry, through the thermal decomposition of methane using biocarbon as a catalyst. Five different biomass samples were used to prepare biocarbons, at a pyrolysis temperature of 1000 °C and a holding time of 90 minutes. When methane was cracked at 1100 °C and a holding time of 90 minutes, the highest hydrogen production was 105 mol/kg biocarbon, using birch bark. The lowest hydrogen yield, of 68 mol/kg biocarbon, was achieved with steam explosion pellets. All biocarbons showed substantial carbon deposition from cracked methane on the surface, with the highest deposition on birch bark and spruce wood biocarbon, of 42 % relative to the biocarbon start weight. The carbon deposition increased with decomposition temperature, methane-share in the purge gas and holding time. The steam explosion pellets, after deactivation, had a CO2 reactivity that is comparable to coke, a reducing agent that is commonly used in manganese producing industry.