“The Catchbio research configuration stimulates progress”

“As a chemical technologist, I like to bridge the gap between catalysis and reactor engineering”, Xander Nijhuis, active in reactor engineering at Eindhoven Technical University, points out. No wonder the collaboration in CatchBio feels like his natural habitat: one of his projects aims to design fuel cells that run on two sugar cubes an hour to power a laptop.

Nijhuis' Delft education and University of Utrecht catalysis experience under Bert Weckhuysen have contributed to his predisposition towards bringing different worlds together. “Although hardcore catalysis researchers and hardcore reactor engineers have more in-depth knowledge of their own field, I'm convinced it is smart to look at both simultaneously, as they are basically inseparable. And that is what we do in our CatchBio research, in close co-operation with catalysis expert Harry Bitter at Utrecht University.”

Collaboration between research groups from different universities is strongly encouraged in the CatchBio programme. “But there is no forced collaboration; we already knew each other well and so did the respective PhD students Fernanda Neira D'Angelo and Thomas van Haasterecht. The Catchbio meetings are very informative about everything that takes place in the field. This works as an impulse on our research. We all see each other regularly also outside this scope, by the way”, Nijhuis concludes. The involvement of industry is also very useful, he says: “For instance to guarantee an optimized focus on IP. When for instance we design an entirely new reactor concept, we think of patenting. But it is very well possible that we can claim much more IP than we think of.”

Simplify first
The ultimate project goal is to develop a stable, non-noble metal based micro-reactor process to produce hydrogen out of various biofeeds. You might translate that to: a battery-size fuel cell running on two sugar cubes an hour to provide the electricity for a laptop.
The problem now is that in an existing, costly reactor with a platinum catalyst part of the sugar feed is hydrogenated, thus using up part of the hydrogen yield and damaging overall process efficiency. One approach towards a solution is to use better and at the same time cheaper non-noble metal catalysts that don't cause hydrogenation. That is the challenge on the catalyst side of the matter.

“Of course there is also the challenge of the reactor”, Nijhuis comments. “You won't reach your goal if you don't go step by step. First you have to simplify the matter. In this case by starting with sugar conversion into hydrogen by aqueous phase reforming. The aqueous phase is important because real life feedstocks are moist and you don't want to dry them first. Although Harry Bitter is working on an alternative catalyst, in our research we use the conventional 'worst case' platinum catalyst on the reactor wall, because we want to investigate whether swift extraction of the hydrogen yield through a membrane works as an alternative way to prevent hydrogenation. Of course we eventually hope to combine this with the new catalyst that also reduces hydrogenation.”

Reaction kinetics
The project is not at that stage yet. It took some time to build a complex microreactor set-up. Researchers used this time for meticulous reaction kinetics measurements of the aqueous phase reforming process, providing them with the roles and influences of various conditions like concentration, pressure and temperature on the reaction speed. Nijhuis: “You have to know those things in order to understand what you are doing and, subsequently, do adaptations. What improvement in yield does the hydrogen extraction cause? How much more conversion of sugars into hydrogen takes place? How large should the reactor be? We don't really know the final configuration, but we are pretty sure we can improve overall reactor efficiency.”