Optimizing NMR system designs for industrial analysis applications of flowing samples
Rutger Tromp defended his PhD thesis at the Department of Mechanical Engineering on March 14th.
The process industry has a great need for accurate measurement systems to analyze moving samples under industrial conditions. Nuclear magnetic resonance (NMR) technology has the potential to fulfill this role. A particularly interesting feature of NMR systems is the potential to measure both transport properties and sample properties using a single measurement technology. Though the challenge with NMR application is that little research has been done at industrially relevant conditions. For industrial use laboratory NMR equipment needs to be modified into robust equipment that can be utilized in harsh environments. In his PhD research Rutger Tromp dives into the flow measurement aspects of NMR as applied in the process industry.
NMR has become one of the most widely used measurement technologies for the study of solids, liquids, and gasses because this technology is versatile, contactless and non-destructive. Next to that NMR systems require minimal maintenance and they can be designed to be intrinsically safe to humans. All these factors make NMR technology very promising, but the available literature of NMR systems being applied to product quality and flow measurements focusses on small-scale laboratory setups. provides a framework to optimize NMR system designs for industrial analysis applications that involve fluid flow-based transport processes with his PhD research.
A simplified modeling framework
With a simple test setup Rutger Tromp evaluated a large variation in transport velocities and transport conditions under industrially relevant conditions, using fluid flow as model transport system. The main results of this study relate to the description of magnetization build-up in flowing fluids in the presence of non-uniform polarization field strengths, polarization field strength dependence of the T1 relaxation time (T1 dispersion), and flow velocity profiles. A simplified modeling framework for these effects was developed based on water flow experiments, T1 dispersion experiments on crude oils, and numerical simulations.
Industrial inline analysis applications
The framework that Rutger Tromp provides is directly applicable to the optimization of NMR system designs for industrial inline analysis applications that involve fluid flow-based transport processes. In addition, the underlying principles of this framework are straightforward to extend to other transport processes, such as sample transport on a conveyor belt, and applications that involve general time-dependent polarization fields.
Titel of PhD thesis: . Promotor: Prof. David Smeulders and Prof. Andy Sederman. Copromotor: Associate Prof. Leo Pel.
PhD in the picture
What was the most significant finding from your research, and what aspects turned out to be most important to you?
"In my research I was able to bring together different research fields within the NMR community: NMR relaxometry, NMR flow measurement, and NMR imaging. By doing this, I was able to obtain a deep understanding of the process in which a fluid is magnetized when flowing though an NMR instrument. This process is a complex interplay between the non-uniform magnetic field distribution in the NMR magnet, and the flow velocity profile and T1 relaxation dispersion behavior of the fluid. Based on this understanding I was able to derive a set of practical engineering equations that can be used to optimize the design of NMR instruments applied to the study of flowing samples. It was only possible to derive these results because we combined expertise in different research fields within the NMR community. As such, I think my research illustrates the value that can be created by taking a holistic view in oneās research, and I think that general insight might be the most influential to me personally."
What was your motivation to work on this research project?
"As a part-time industrial PhD candidate, I was in the lucky position to have one foot in the commercial research and engineering community, and one foot in the academic research community. This was a situation that was both challenging, as either has their own specific goals and mindset associated with it, and deeply inspiring and motivating. I was able to take a concrete problem from a commercial NMR measurement instrument manufacturer as inspiration, while at the same time having the focus to go into the full academic depth of the problem. In the end, this resulted in a deep understanding of the underlying physics that could be formulated in a general way that is applicable to not only the original NMR flow measurement problem that inspired the work, but to the much more general class of NMR measurement in which the magnetic polarization field is time dependent. Seeing both the practical engineering and general academic implications of your research fold out in front of me was highly motivating."
What was the greatest obstacle that you met on the PhD journey?
"Although being a part-time industrial PhD candidate was inspiring and exciting in general, at times it was quite challenging and frustrating as well. Balancing these two worlds requires quite a bit of time management. Especially in the first few years of my journey I struggled, and, honestly, suffered quite a bit from not being able to meet the ambitious timelines I set for myself. As most PhDās will recognize, at some point along your journey you start asking yourself doubtful questions about āIs this really what I want to do?ā and āAm I ever going to finish this?ā. I found it to be helpful to feel the support in my PhD journey from both my supervisor and my senior colleagues in industry who had finished their PhDās themselves. I guess like with most things in life, the greatest obstacle is that doubtful and at times self-sabotaging voice in your head. As such, I believe that a social support system is the greatest asset anyone can have while pursuing a PhD; you might start out faster alone, but youāll get further together."
What did you learn about yourself during your PhD research journey? Did you develop additional new skills over the course of the PhD research?
"One of the greater insights I obtained during my PhD research was that my masterās research might have shown that I was smart enough to solve complex research problems, but it requires a whole different brain to transform that piece of research into a story that can be effectively communicated. To me, that is the pivotal difference between a masterās and a PhD research project. Although there obviously still is room for improvement, I can see that over this PhD journey I improved a lot in my communication skills. Especially, in terms of being critical about your own writings by not only focusing on the content, but also on the form in which this content is perceived. In this light, the slogan āwriting is deletingā might cover the main lesson learned in this respect."
What are your plans for after your PhD research?
"Being a part-time industrial PhD candidate, I will continue my journey with the company KROHNE that sponsored my PhD journey. Iām looking forward to continue working in KROHNEās innovation department to develop the process instrumentation of the future. I am excited to start this new phase in my career with the recent developments in real-time simulation and AI technology in mind to strengthen the modeling capabilities to drive new innovations within KROHNE."