Beyond the boundaries of electricity and hydrogen
The waste products released when burning conventional fuels are damaging our environment. This is something that the entire world now agrees upon. Alternative energy sources and means of power are rapidly gaining popularity. But it sometimes feels like the search for alternative energy has not made it further than electricity. Sustainable generation of electricity is in itself a fine development, but it perhaps falls short of being the holy grail in the quest to find solutions for the global demand for energy. It is, for example, easy to store in batteries, but not yet on a large scale, or for the longer term.
Hydrogen is a more efficient and greener alternative. But current availability is marginal. Several specialists at TU/e decided to take on the challenge of developing an unconventional alternative.
Metal fuels
For those unfamiliar with the field, this subheading may sound more like the name of a band driven by heavy guitars and a highly motivated drummer. But it in fact refers to a significant and promising replacement for conventional carbon-based fuels: metal particles, charged with massive amounts of energy, that release this energy in a controlled manner. This ‘metal powder’ is ideally suited to energy-intensive processes. Following combustion, the particles are retrieved and recharged, creating a fully circular process. There are more advantages, since metal can hold much more energy per cubic centimeter than a battery and storage is without notable challenges. It does not require compressing or cooling, for example. We discuss the subject with Dr. Mohammadreza Baigmohammadi, postdoc researcher in the Power&Flow group, supervised by Professor Phillip de Goey. This group focuses on innovations in the field of combustion.
Explosions and melting points
Metal powder can contain large amounts of energy. It is for good reason that, for centuries, it has been a popular ingredient in explosives and fireworks. But an explosion is a short, violent release, and this research explores how to release the energy over a longer period of time. And that brings with it challenges, as Mohammadreza explains: “To start with, we need to control the temperature. We want to heat the metal particles to close to melting point. If they get too hot, the particles vaporize. They then become nanoparticles, which are a lot more difficult to retrieve. We want to keep the particles intact. That is our primary focus.”
Not all at once
Heating the powder releases energy. This release can also cause the temperature to rise even more. Up to this point, the process resembles standard fuel combustion. But there is a big difference, says Mohammadreza: “Conventional fuels behave predictably. They combust in a phase in which they are gases. We call this type of combustion ‘homogeneous. In other words: everything burns at the same time. With metal powder, each particle burns individually. It is called heterogeneous combustion. But the particles do react to each other, which is not the case in standard fuels. We can make metal powder combust less explosively by adding air, and therefore oxygen.”
Slides and buttons
Mohammadreza believes that the solution can be found in a range of parameters, which he calls the ‘slides and buttons’ of the project. “The amount of oxygen in the air during combustion is one of these slides and buttons. To ensure that the combustion is manageable, we lower the level. But less oxygen also means less combustion. So, we are exploring ways of preheating the fuel, so that it is sufficiently warmed up when it enters the engine, and less oxygen is required to keep the process going. We are looking into multiple approaches and systems for managing the flame.”
The future
The team has now established the most important parameters for safe and yet sufficiently violent combustion. “We are making serious progress. We now need to find out how these parameters interact, and how we can apply them in this type of combustion.” Metal powder power is suitable for use in e.g. power stations. Mohammadreza notes that it gets more difficult in cars: “The size of the engine does not really matter. But managing the fuel is crucial, because we are using particles instead of gases. That is why we think the technology will primarily be used in external combustion engines in the future. You will need an external heat outlet. If cars with external engines are developed, we see opportunities.”
Mohammadreza expects to have a working demo within two years: a lab prototype. “We’ll then also be able to demonstrate to companies what we are doing. That is an essential step to securing new investment.”
Only at TU/e: also considering recycling
Mohammadreza says that many other universities are also focusing on improving the processes associated with traditional pyrotechnics and explosions. “We are doing things differently. The others are solely focusing on combustion. Our focus is on combustion and recycling, which is unique to TU/e. We are truly frontrunners in this field. Currently only TU/e and the McGill University in Canada are working on this process, that is, on an utterly new type of sustainable energy. Which is not always easy, as you sometimes run up against skepticism. People want to see proof first. Some companies are active in the field, and we are in contact with them. But in general, everyone just looks to each other and is waiting to see what happens. And in this context, we are the pioneers.”
Pioneering with technology
We are filling a gap between pure research and projects. Large companies are also getting involved. We regularly consult with industrial parties, and they like the sound of this. But in general, they invest more heavily in improving existing methods. When it comes to alternative technologies, they prefer to see how things work out for others before getting stuck in themselves. Everyone is waiting for everyone else. We are the pioneers. We can come up with something completely new. If you develop a new technology, you have control of everything. You have multiple roles, key roles. And the result is so much valuable technological expertise! In technological projects, it is customary for researchers not to release everything. With what we learn, we will soon be in the position to give energy transition a boost. That alone is a pleasing thought.
Motivation
Mohammadreza gets his energy and motivation from small, positive signals and the conviction that technology offers hope. “You need to be a little crazy, to look at existing systems and problems in new and different ways. If you don’t, you will never discover anything new. A shrewd researcher knows where to look. It can certainly take a long time, and you sometimes do not know where to start discovering, but you keep going. Because you believe in it. And after digging for a long time, perhaps you will find a treasure.”
Why is the Fund important?
“Without the Fund, this research would not exist. It’s that simple,” says Mohammadreza. “Phillip de Goey’s research depends on it. The Fund supports projects that do not immediately produce prototypes or concrete results. Important projects like these actually sometimes provide the foundations for further-reaching discoveries. If we can lay the foundations, we will have truly changed something. We will have helped make the world a better place. It is great that the Fund supports this notion. In words, but of course particularly with financial support.”