Researchers around the world are working to produce sustainable ammonia for use in fertilisers. DTU is at the forefront of the developments and expects to be able to market a solution within the next few years.
Ammonia is a necessary part of the fertiliser that enables food production all over the world. Currently, ammonia is produced in large plants using a significant amount of energy, as the process requires very high temperatures and high pressure. As a result, more than one per cent of the world's total energy consumption is used to produce ammonia.
For many years, researchers have looked for a more sustainable way of producing ammonia using electrocatalysis and water and nitrogen from the air.
For the past three years, the young researcher Suzanne Andersen has been part of the research group at DTU Physics working in this field. Here she has helped lay the groundwork for a solution that she believes can be commercialised soon.
"Our goal is to produce a small black magic box that can be sold to farmers and plant nurseries all over the world. By using the electrocatalytic process that happens in the box, they will be able to produce sustainable ammonia for fertiliser on their own property. All it takes is electricity, e.g. from a wind turbine or solar panels, as well as hydrogen from water and nitrogen from the air," says Suzanne Andersen.
Measurement methods had to be in place first
However, the road to the black box started in a completely different place. Suzanne Andersen's initial project was to develop a protocol for how to measure whether, for example, an electrocatalytic process actually succeeds in creating ammonia. This was necessary because many researchers mistakenly believe that they have found a solution for producing ammonia.
"Ammonia is found throughout our surroundings, including in the air we exhale. So it's essential to measure in the right way in the lab, so you can be sure that the ammonia comes from the experimental setup," says Suzanne. The protocol was subsequently published in the prestigious scientific journal Nature and is now used by scientists around the world.
Patent for cyclical method
Once the measurement methods were in place, Suzanne Andersen's next goal was to develop a process that could produce ammonia using electrocatalysis, hydrogen and nitrogen – a process that could take place in a laboratory under normal temperature and pressure conditions.
"We based our work on the experiments of a group of Japanese researchers who succeeded in producing ammonia in 1993. The challenge, however, was that both this and other methods have so far only been able to run for a few hours, after which the resistance becomes too great to be able to continue the catalysis. So I decided to try a cyclical process instead," Suzanne continues.
The cyclical process means that the catalysis is applied with high potential for one minute, followed by lower potential for a couple of minutes. This process is repeated continuously, making it more stable and efficient than in previous experiments.
"We managed to get the cyclical process to run in the lab for five days in a row. I'm sure it could easily have continued, but for practical reasons we had to stop the experiment at that time," says Suzanne.
The research team at DTU Physics has patented the method, and are still working on making it as effective as possible. Among other things, they are looking at finding the right time intervals in the cycle.
At the same time, Suzanne Andersen and her colleagues are working to make the process more stable and scale it up so it can be done not only in 1 cm2 in a laboratory, but on a much larger scale in the real world.
Suzanne Andersen is sure that they will be able to prepare the ammonia production for the commercial market over the next couple of years, and that the little black magic box will become a reality.
