Detection of colloid motion in deep bed filtration processes by means of Fast-X-Ray-Tomography
Deep bed filtration is a complex process, driven by manifold interacting mechanisms on various scale levels. It strongly depends on the interaction of the apparent flow field and the collector structure but also on the loading of the filter. With established 3D imaging techniques such as X-ray µ-tomography and NMR flow measurements it is possible to measure the filter loading at different times and the three-dimensional flow field (Fig. 1). Based on previous research activities (P07/01 and P06/02) the aim of this project is the development of methods, which allow the tracking of colloid motion on the one hand and colloid deposition on the other hand. For this purpose, fast-tomography measurements will be carried out for an adapted model-filtration experiment. The motion of single particles has to be tracked individually and will be visualized by traces in the tomographic data. Particle deposition sites and their spatial position may be identified as partial volumes. The advantages of µCT and NMR flow measurements can thereby be combined in one method. Furthermore, the local information on single particle motion will be validated with information obtained by accompanying global flow measurements, carried out in cooperation with the work group “In vivo MR” (P05/01). Another aim is to transfer these new experimental results to the colloid filtration theory. For this purpose a close cooperation has to be established with numerical sciences within the graduate school “MIMENIMA”. The combination of filtration experiments, NMR flow measurements and numerical simulations of multiphase flow in high complex geometrical structures allows the scaling of microscopic colloid retention and deposition mechanisms to macroscopic models. A close linking cooperation also exist with the PDC group, which provides the necessary monolithic ceramic model geometries used in the experiments.
Fig. 1: Reconstruction of a porous sample from x-ray tomography data. Particle deposition sites are shown in red.
Publications within MIMEMIMA:
Mikolajczyk, G., Huang, L., Wilhelm, M., Dreher,W., Odenbach, S., 2017. Colloid deposition in monolithic porous media – Experimental investigations using X-ray computed microtomography and magnetic resonance velocimetry, Chemical Engineering Science 175, 257 – 266.
Huang, L., Mikolajczyk, G., Küstermann, E., Wilhelm, M., Odenbach, S., Dreher, W., 2017. Adapted MR velocimetry of slow liquid flow in porous media. J. Magn. Reson. 276, 103–112.