Ammonia as a hydrogen storage medium

Ammonia is currently regarded as one of the most promising storage and transport media for hydrogen. Large quantities of hydrogen can be transported relatively easily in the form of ammonia. At the same time, ammonia offers the advantage that it can be stored and transported in liquid form at atmospheric pressure and temperatures of -35 °C. This makes it particularly suitable in areas such as the transportation of hydrogen by ship over long distances or in places where a long storage period for hydrogen is required.

One of the hurdles on the way to using it as a hydrogen storage medium: ammonia is usually produced on an industrial scale from nitrogen and hydrogen using the Haber-Bosch process. The standard method is to provide the required hydrogen from natural gas via steam reforming. In global terms, this process causes more than 450 million tons of CO2 emissions per year.

Another challenge is posed by cracking – the splitting of ammonia into water and nitrogen. Existing technologies focus on centralized cracking, e.g. at ports. There is a lack of small-scale solutions for decentralized cracking, which offers several advantages: It enables flexible and direct use of hydrogen at many locations and can be more cost-efficient. This is because the cost of transporting hydrogen over the last mile to the user and local decentralized storage can account for up to 50 percent of the total costs.

Fraunhofer UMSICHT is working on more energy-efficient synthesis and cracking processes when using electricity from renewable energies. These include, in particular, electrochemical ammonia synthesis and plasma-based ammonia synthesis. The latter takes place in a sliding arc reactor with energy-efficient, cold nitrogen excitation using cost-effective non-precious metal-based catalysts and offers further energy benefits through synthesis at atmospheric pressure.

With regard to the decentralized cracking of ammonia, we are working on electrically heated reactors that heat the catalyst bed with significantly higher efficiency than in established processes: directly instead of indirectly via a jacket heater. This is also done using electricity, so that the system can potentially decompose ammonia with very low CO₂ emissions.

Specifically, our services include

• Development of methods and processes for storing, transporting and converting hydrogen into various derivatives such as ammonia, methanol, fuels or chemicals
• Development of methods and processes for storing, transporting and converting hydrogen into various derivatives such as ammonia, methanol, fuels or chemicals
• Development of electrically heated reactor systems
• Catalyst development and testing 
• Process engineering simulation and modeling 
• Plasma reactor development

Fraunhofer flagship project »AmmonVektor«

to the website

Catalysts for industrial use

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Influence of the catalyst precursor for cobalt on activated carbon applied in ammonia decomposition

to the publication of 01.03.2024