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NMR Methods for a comprehensive and fast characterization of mass transport and catalytic reactions in porous materialsWednesday (07.10.2020) 13:40 - 14:00 Room 3 Part of:
Nuclear Magnetic Resonance (NMR) is a powerful toolkit for non-invasively investigating static and dynamic properties of fluids inside porous structures. The flexibility in choosing different NMR measurement techniques allows for in situ analysis of velocity, diffusion, temperature and concentration of species in complex and opaque porous structures. The result of such analysis accurately characterizes mass transport properties and helps to improve numerical predictions. In this contribution, developed NMR techniques are illustrated that accurately characterize diffusion, flow, and temperature in ceramic open-cell foams used as catalyst carriers or filters in deep bed filtration.
Localized analysis of mass transport was conducted to characterize diffusion and dispersion of thermally polarized gases in open-cell foams with different pore densities. Additionally, the influence of mechanical and diffusional dispersion at various flow rates was investigated using a developed spatially resolved NMR method. An optimized diffusion weighted technique was used for in situ analysis of temperature in catalyst supports. Using this technique on ethylene glycol, glycerol and the temperature stable ionic liquid Pyr13 [TFSI] as NMR thermometers, measurements were performed in a temperature range from 20 to 160 °C. This allowed axial temperature profiles in catalyst carriers used in gas phase reactions by introducing three NMR-thermometers for accurate and consistent measurement of temperature.