For years, hydrogen has been hailed as one of the solutions to a growing problem of energy dependency. While fuel and energy use are on the rise and greenhouse gasses worsen climate change, hydrogen can be produced cleanly.
Hydrogen is still far from becoming the silver bullet that will eliminate our dependence on fossil fuels, but its applications in industry are extensive already. From ammonia production, oil refining, or use in the metallurgical industry, the demand for hydrogen is growing. This growth has triggered an acceleration in the race to find more sustainable and cheaper production pathways of this fuel.
Hydrogen can come from different sources and through multiple processes. From extraction of natural reserves to coal gasification, sources can be completely clean or relatively contaminant. A promising method is catalytic methane cracking. It consists of breaking down methane in its individual components, hydrogen gas and solid carbon, without carbon dioxide emissions. Methane can be obtained from waste and biological processes, as well as found in natural gas.
But catalytic cracking is not that simple. The main drawback is the high temperatures required for this reaction to take place.
This is where catalysts come into play. Catalysts are materials that act as accelerators, essentially lowering the energy barrier required to start the reaction. The latest science shows that catalysts allowed for catalytic cracking temperature reductions of between 30 and 42%, which greatly improves process efficiency.
Metal vs carbon-based catalysts for green hydrogen from methane cracking
Metallic catalysts are most often used for catalytic cracking of methane. The most studied are nickel, cobalt, and iron, with nickel achieving the best performance. These metals are often used in conjunction with supports such as silica or alumina. These supports improve the dispersion and thermal resistance of the catalyst, increasing yields.
But metallic catalysts have issues. During the reaction, both hydrogen and carbon are generated. This carbon deposits on the metal, and deactivates it, stopping its function as a catalyst
2This has led the scientific community to search for more stable options, such as carbon-based catalysts. These include graphite, activated carbon, carbon nanotubes, diamond powder, etc.
The main advantage of these compared to metallic catalysts is their longer use time and lower cost. Also, carbon is present everywhere, but certain metals are much rarer. Within the carbon-based catalysts category, a special mention goes to biocoal-based catalysts, which are specifically derived from biomass or biocarbon through pyrolysis processes, a controlled and slow burn leaving mostly the carbon behind. These catalysts are a sustainable option for methane cracking.
And what is the main disadvantage? Hydrogen production rates do not reach the efficiency of nickel catalysts. There is a trade-off between efficiency and cost. The current challenge for methane cracking is to design biocoal-based catalysts that achieve production rates close to those of nickel.
Turning biowaste into catalysts: a pathway to circular hydrogen and carbon
At H2STEEL, we are turning waste into carbon-based catalysts to produce hydrogen and carbon from biomethane. To do so, the first step is to put organic-matter waste (several types are used) through a pyrolytic process, to leave nearly only the carbon behind. The resulting biochar can then be used to develop the catalysts for methane cracking. The characteristics of these catalysts will differ depending on the source waste and the process parameters (time, temperature, etc.).
Using these catalysts, hydrogen and carbon can be obtained from methane. Making methane cracking for hydrogen production efficient offers a route for a fuel with zero CO2 emissions, and even negative carbon emissions when biomethane is used. This idea drives H2STEEL forward towards the goal of achieving carbon neutrality and a real positive environmental impact.
Circular carbon for steel: a climate-positive opportunity
Moreover, hydrogen is not the only product. The carbon generated, which deposits on the catalyst, is a high value-added product can replace metallurgical fossil coke in steel production. The steel industry is characterized by high carbon consumption. Because of this, the whole process can go fully circular, with the carbon produced used as coke, and the hydrogen as fuel to power the metallurgy industry.
We at H2STEEL aim to combine advanced hydrogen and carbon production technologies with the steel industry, using the carbon generated in the process to help decarbonize one of Europe’s most carbon-dependent sectors, supporting the ecological transition of metallurgy by circular bio-coal production for biowaste.