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

Abstract

first_pagesettingsOrder Article Reprints Open AccessArticle Catalytic Methane Decomposition for the Simultaneous Production of Hydrogen and Low-Reactivity Biocarbon for the Metallurgic Industry by Roger A. Khalil 1,*ORCID,Sethulakshmy Jayakumari 2,Halvor Dalaker 2,Liang Wang 1ORCID,Pål Tetlie 2 andØyvind Skreiberg 1ORCID 1 SINTEF Energy Research, P.O. Box 4761 Torgarden, NO-7465 Trondheim, Norway 2 SINTEF Industry, P.O. Box 4760 Torgarden, NO-7465 Trondheim, Norway * Author to whom correspondence should be addressed. Energies 2025, 18(3), 558; https://doi.org/10.3390/en18030558 Submission received: 9 December 2024 / Revised: 15 January 2025 / Accepted: 20 January 2025 / Published: 24 January 2025 (This article belongs to the Section B: Energy and Environment) Downloadkeyboard_arrow_down Browse Figures Versions Notes Abstract 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 from increasing by 1.5 °C, 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 with a holding time of 90 min. When methane was cracked at 1100 °C with a holding time of 90 min, the highest hydrogen production was 105 mol/kg biocarbon, achieved using birch bark. The lowest hydrogen yield, of 68 mol/kg biocarbon, was achieved with steam-explosion pellets. All the biocarbons showed substantial carbon deposition from cracked methane on their surfaces, with the highest deposition on birch bark and spruce wood biocarbons of 42% relative to the biocarbon start weight. The carbon deposition increased with the decomposition temperature, the methane share in the purge gas and the holding time. The steam-explosion pellets, after deactivation, had a CO2 reactivity that was comparable to coke, a reducing agent that is commonly used in manganese-producing industries. About 90% of the potassium and sodium were removed from the biocarbon during catalytic decomposition of methane performed at 1100 °C. The alkali removal was calculated relative to the biocarbon produced under the same conditions, but with 100% N2 purge instead of CH4. After catalytic decomposition, the surface area of the biocarbon was reduced by 11–34%, depending on the biocarbon type.