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Item type:Publication, Access status: without files , Measuring electrical conductivity using MRI(2025-03-31); ; Magnetic Resonance Imaging (MRI) is a powerful technique in the field of chemical engineering. Properties such as spin density, velocity, diffusion, chemical shift or temperature can be measured using MRI, providing insights into complex systems. Expanding the measurement capabilities to include additional properties can further increase the understanding of such systems. One such property is the electrical conductivity, which is already measured in medical applications [1]. Conductivity plays a major role in many (electrochemical) processes and can also be used to deduce other quantities. For instance, conductivity has a proportional relationship with temperature, which can be used to determine absolute temperature values in complex chemical engineering reactors through conductivity measurements. To measure conductivity using MRI, a steady-state free precession three-dimensional scan is performed, with the numerical second derivative of the B1 phase yielding the value [1]. Initial phantom measurements using a unique vertical MRI scanner are presented along with the complex numerical reconstruction of the conductivity. The concept is then extended to a temperature measurement, with the goal of applying these measurements to real chemical reaction systems. References: [1] Katscher et al., NMR in Biomedicine 30 (2017) e3729.Publicationtype: Conference Poster23 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , The TUHH process imaging system(2025-03-19); ; ; ; Chemical engineering is a crucial field in the production of many essential goods, with its processes undergoing major changes in the transition to a less fossil-dependent product chain. Yet, understanding these processes is often based on modeling and measurements with integral or local invasive sensors. Tomographic techniques such as magnetic resonance imaging (MRI) can overcome these limitations and provide essential information. However, MRI systems are typically not constructed with the needs of (bio)chemical reactors in mind. Most vertical MRI systems feature probe diameters of below 8 cm and maximum sample heights of below 1 meter. On the other end, clinical MRI systems are usually built horizontally and feature bore sizes of bigger than 30 cm and maximum sample lengths of a few meters. In these system, processes based on gravity have to conform to the bore size and are therefore limited. The TUHH system combines the advantages of both systems. It is a vertical bore magnet with a 40 cm bore diameter. Sitting on legs at 4 m height, samples of up to 3 meters can be measured. This is especially relevant for reactors based on gravity such as fluidized beds or bubble columns. The magnet itself is a cryogen-free magnet with a field strength of 3 T. The system is freshly commissioned in 2024 and is planned to be used in various projects. In particular, the work of Alexander Penn in ultrafast imaging will be continued and extended in scope[1,2]. A main focus here are fluidized beds and liquid-gas reactors, which can be investigated with temporal resolutions below 30 ms. Furthermore, techniques such as thermometry and chemically resolved imaging will be employed to reveal the processes inside important reactor systems. This work has been funded by the Deutsche Forschungsgemeinschaft: instrumentation proposal 422037415, research proposals 471615686 and 544956881 and the collaborative research center ”SMART Reactors” (503850735).Publicationtype: Conference Poster48 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Magnetic resonance imaging for 3D-printed structured packingsStructured packings are introduced as column internals for gas-liquid contacting to improve mass transfer and hydraulic parameters. The flow conditions within the column strongly depend on the design of the structured packings and correlate directly with the liquid holdup, mass-transfer rates, capacity, and pressure drop. The usually opaque columns prevent the direct optical measurement of parameters, such as the spatial distribution of the involved phases, thus impeding an evaluation and exploitation for the optimization of the design. To overcome this limitation, tomographic techniques can be utilized, which enable non-intrusive, temporally and spatially resolved measurements. In this study, we use magnetic resonance imaging (MRI) to measure the flow and the spatial distribution of water and air in a column with structured packings. The measurements are performed with a novel and worldwide unique vertical MRI scanner at Hamburg University of Technology. Structured packings with a diameter of 54 mm and a total height of 1 m are studied. Several 3D-printed packing designs, optimized with CFD simulations are measured with varying gas and liquid velocities. The detailed measurements of gas-liquid hydrodynamics within structured packings might enable the validation of numerical simulations and provide a comparison to established X-ray tomography data.Publicationtype: Conference Presentation95 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , The TUHH process imaging system(2024-08-26); ; ; 75 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , MRI in chemical engineering applications(2024-08-13); While magnetic resonance imaging has become a standard technique in the medical field, it has seen limited application in the field of chemical engineering. Due to the importance of this field and the lack of understanding of the internal processes in many reactor types, MRI has the potential to provide novel insights. While the technique has marked advantages in the field of chemical engineering such as the ability to measure opaque systems, velocity and chemical shift, there are challenges such as limited sample size, low temporal resolution, and technique specific properties. At the Institute of Process Imaging at Hamburg University of Technology, our goal is to overcome these challenges. This talk tackles three challenges with MRI in chemical engineering. * Size: Chemical reactors often rely on gravity. Therefore, a vertical system is best suited for measurement. However, most vertical systems only provide less than 7 cm of usable diameter. On the other hand, clinical scanners with higher diameters are oriented horizontally, limiting their capabilities. The TUHH vertical MRI scanner is a unique system designed to image pilot-scale reactors overcoming these limitiations. * Low temporal resolution: The temporal resolution of MRI has always been a challenge and only recently has improved significantly. Similar to the clinical field, parallel imaging and dedicated reconstruction enable temporal resolutions in the millisecond range. These make it possible to investigate dynamic systems. Especially challenging is the measurement of chemical compositions. Progress has been made to improve on these time consuming measurements. * Technique specific properties: MRI can deliver three-dimensional velocity fields. However, comparing these measurements to computational fluids simulations (CFD) often results in discrepancies. These can be the result of an unfair comparison, since MRI and CFD display different states of the system. Using a MR-Simulator (JEMRIS) and CFD-DEM simulations, the extent of these differences as well as the fairest way to compare can be obtained.Publicationtype: Conference Presentation67