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How to tame bubbles in electrolysis
by Niels Deen, TU/e and EIRES |
Can you introduce yourself and your expertise in water electrolysis?
I’m Niels Deen, professor in multiphase and reactive flows at the TU Eindhoven. My passion is developing tools that help us understand multiphase reactive systems, like electrolysers, bubble columns, fluidized beds or even blast furnaces for steel making. All this equipment has in common that a good toolset for studying the multiscale multiphase multiphysics going on inside enables us to develop new more clever design choices. It’s all multi-multi-multi, which makes it so exciting and challenging.
 Specifically on water electrolysis, together with my team (Aled Meulenbroek, Faeze Khalighi, Yali Tang and Bert Vreman) I develop tools to describe the transport phenomena around a single hydrogen bubble growing on an electrode. That sounds very simple, but it really is not. A lot of physical processes come together in this seemingly simple problem: multiphase flow, heat transfer, mass transfer, and variable potential fields. Variations in the temperature, species concentration and/or surface charge lead to variations in surface tension on the bubble surface. This in turn creates non-intuitive flow on the bubble surface that finally influences the performance of the entire electrolyser. So, long story short, we need to zoom into the surface of a 100 micron hydrogen bubble if we want to improve the operation of a complete electrolyser stack. |
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What inspired you to pursue research in understanding of bubble dynamics in electrolysis?
Having worked on bubbly flows for 25 years, I noticed that there are a lot of open questions related to the multiphase flow in electrolysis. And since greening the process industries will involve a lot of electrolysis, developing new tools and knowledge is very timely. |
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What were the main takeaways you aimed to convey to the audience?
The main take away is: differences in concentration and temperature at the electrode surface play a key role in the size of bubbles being generated. Small bubbles are hard to handle, so we need ways to manipulate and control what’s going on at the electrode surface. |
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What were the main takeaways you aimed to convey to the audience?
The main take away is: differences in concentration and temperature at the electrode surface play a key role in the size of bubbles being generated. Small bubbles are hard to handle, so we need ways to manipulate and control what’s going on at the electrode surface. |
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How do you envision your research influencing future developments in water electrolysis?
I believe that the insights presented in my talk will contribute to developing closure laws on bubble size and, associated with that, the electrical resistances due to the presence of bubbles. Reducing electrical resistance is key to improve the efficiency and reduce the costs of electrolysis. |
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How do you perceive the collaboration between University of Eindhoven and Delft e-Refinery Institute in research and academic initiatives?
I see a lot of existing connections between the e-Refinery and the Eindhoven Institute for Renewable Energy Systems (EIRES) and I believe that in the upcoming HyPRO research programme we can further intensify these contacts. Personally I have always had a very pleasant collaboration with Johan Padding and his team and I look forward to extending that. |
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Have there been any significant collaborative projects or partnerships between your institution and e-Refinery Institute?
We have a very nice collaboration on understanding the fundamentals of bubbles in electrolysis within the Bubblelectric programme. This programme connects four PhD students at TU/e, TUD and UT and is sponsored by NWO, Nobian, Nouryon and Shell. |
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How do events like the lunch lecture contribute to fostering collaboration and knowledge exchange between universities?
I know from my experience at TU/e that lunch lectures are a very nice way to exchange latest insights and to trigger discussions. In Eindhoven we have the very successful bi-weekly EIRES lunch lecture on Fridays (see: tue.nl/eires) where 100-200 people join online. Although it is much easier to have discussions in person, I think there’s also something to say for an online lunch lecture. It makes it easier to attend a lunch lecture for people far away from your own institution. |
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The e-Refinery Lunch Lectures are open to all interested parties and are accompanied by a delicious lunch. You must therefore register for it. The lectures always take place at the TU Delft campus.
You can find the announcements here.
The lectures are regularly recorded. You can watch the lectures here.
Next lectures:
May 14: Pieter Levecque – Battolyser Systems
Sep 3: Tim Nijssen – TU Delft
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