X-ray tomography scan of partially dewatered filter cake
datacite.FundingReference.funderName | Deutsche Forschungsgemeinschaft | |
Contributing person | Technical University Bergakademie Freiberg - Institute of Mechanical Process Engineering and Mineral Processing | |
Contributing person | Löwer, Erik (orcid: 0000-0002-6956-8054) | |
Contributing person | Esser, Simon | |
Contributing person | German Research Foundation | |
Contributing person | Leißner, Thomas | |
Contributing person | Peuker, Urs Alexander | |
datacite.description.SeriesInformation | fully saturated ('filtration') and dewatered state ('irreducible saturation') | |
datacite.description.TableOfContents | CF_035_055200_023 (in-situ filtration and dewatering, fully saturated and dewatered state, total filter cake) | |
Documentation of the data | Methods: VDI 2762-1, VDI 2762-2 and VDI 2762-3 Resource Type: X-ray tomography scans of partially dewatered filter cake (.tiff stacks) Data Acquisition: in-situ filtration and dewatering (downscaled pressure nutsch 5 mm diameter) according VDI 2762-2 and VDI 2762-3 Data Processing: automatic centre shift, beam hardening correction (factor 0.05), gauss smoothing filter (kernel 0.7) see note parameter.png in each measurement file for further measurement and reconstruction parameters | |
References to related material | 10.1016/j.seppur.2020.117854 | |
Description of the data | Publication D: Network model of porous media – Review of old ideas with new methods(Paper_D) The paper takes up the old ideas of describing porous media with several tube and network models. The wellknown models received from literature gave a good concept of dewatering equilibria resulting in capillary pressure curves and pore size distributions (PoSD). However, numerical methods and measurement techniques were not sophisticated allowing to evaluate the models appropriately. In this work, a numerical method based on statistics is introduced to validate the network model of FATT from 1956: The porous filter cake structure is implemented as a matrix, which elements represent the pore size correlating with the capillary entrance pressure for each pore. The input for the calculations can be any mathematical approximation of a PoSD, which can be derived from capillary pressure tests or micro computer tomography (μCT) analysis of the filter cake. A procedure based on the concept of FATT is presented to generate dewatering equilibria for different applied pressures. Therefore, the elements of the matrix are checked to be ‘dewatered’ regarding to their size, position, the applied pressure level and the progress of dewatering. The network model known from literature is improved by implementing additional conditions for the description of physical phenomena, such as the formation of residual bridge liquid or hydrodynamic isolated areas. X-ray microscopy, mercury intrusion tests and laboratory desaturation experiments by using semipermeable membranes for capillary pressure tests are used to validate the pore size distribution. The different results are integrated into the matrix model as starting parameters. For the laboratory experiments, the PoSD is calculated from the measured capillary pressure curve, using the distributed tube model and the YOUNG-LAPLACE-equation on an equal basis to the established mercury intrusion analysis. However, with the tomography measurements, it is possible to determine PoSD using different defined geometry elements fitting inside the pore space. The force balance is evaluated at the pore entrance by using the wetting line of the pore throat. The direct measurement of the void geometry allows the calculation of the pressure distribution without the LAPLACIAN assumptions. In this way, the difference between experimental, measured and modelled PoSDs is emphasised to validate the old (and improved) ideas of network models describing porous media | |
Type of the data | Dataset | |
Total size of the dataset | 10398894446 | |
Author | Löwer, Erik | |
Upload date | 2021-08-24T05:37:43Z | |
Publication date | 2021-08-24T05:37:43Z | |
Publication date | 2026-06-05T11:15:55Z | |
Data of data creation | 2019 | |
Publication date | 2021-08-24 | |
Abstract of the dataset | X-ray tomography image of a partially dewatered filter cake. The initial slurry contains Al2O3 particles suspended in a potassium iodide-glycerol solution. These were separated by cake-forming filtration followed by dewatering. All filtration and dewatering experiments took place in an in situ apparatus within the Zeiss Xradia 510 X-ray microscope. The filter cake is dewatered until the minimum degree of saturation is reached within the pore space. A scan is taken at the equilibrium state before and after dewatering. | |
dc.identifier | CF_035_055200_023 filtration | |
dc.identifier | CF_035_055200_023 irreducible saturation | |
Public reference to this page | https://opara.zih.tu-dresden.de/handle/123456789/2532 | |
Public reference to this page | https://doi.org/10.25532/OPARA-126 | |
dc.language | eng | |
Publisher | Technische Universität Bergakademie Freiberg | |
Licence | Attribution 4.0 International | |
URI of the licence text | http://creativecommons.org/licenses/by/4.0/ | |
Specification of the discipline(s) | 4::42::403::403-03 | |
Specification of the discipline(s) | 4 | |
Title of the dataset | X-ray tomography scan of partially dewatered filter cake | |
dc.title.alternative | fully saturated and dewatered filter cake | |
Research instruments | X-ray microscope (ZEISS Xradia Versa 510) | |
Underlying research object | glycerol (manufacturer: Carl Roth, > 99,8 %, 24 m.-%) | |
Underlying research object | potassium iodide (manufacturer: Carl Roth, > 99 %, 25 mmol/l) | |
Underlying research object | gamma-Al2O3 (manufacturer: Almatis, solid powder, 55...200 µm) | |
Software | Xradia XMReconstructor (Version 11.1) | |
Project abstract | Reliable information about the micro-processes during filtration and dewatering of filter cakes allows more accurate statements about process development and design in any industrial application with solid-liquid separation units. Distributed particle properties such as shape, size, and material influence the porous network structure with considerable local fluctuations in vertical and horizontal alignment in the cake forming apparatus. The present work relates to a wide range of particle sizes and particle shapes and presents their effects on integral, but preferably local, structural parameters of cake-forming filtration. Current models for the relationship between particle properties and resulting porous structure remain inaccurate. Therefore, the central question focus on the model-based correlation between the obtained data and characteristic cake and process parameters. In combination with X-ray computed tomography and microscopy (ZEISS Xradia 510), data acquisition on the structural build-up of filter cakes is possible on a small scale (filter area 0.2 cm²) and a conventional laboratory scale (filter area 20 cm², VDI 2762 pressure nutsch). Thereby, the work focuses on structural parameters at the local level before, during, and after cake dewatering, such as porosity, coordination number, three-phase contact angle, characteristics of pores and isolated liquid regions, the liquid load of individual particles, tortuosity, and capillary length, and the corresponding spatial distributions. Seven different particle systems in the range of 20 and 500 µm, suspended in aqueous solutions with additives for contrast enhancement, served as the initial raw materials for the filter cake build-up. Image data processing from 16-bit greyscale images with a resolution of 2 to 4 µm/voxel edge length includes various operations from denoising filters and shape enhancement with two-stage segmentation to identify air, solid particles, and liquid phase, resulting in a machine learning-based automated approach. Subsequent modeling and correlation of measured parameters rely on experimentally verified quantities from mercury porosimetry, laser diffraction, dynamic image analysis, static and dynamic droplet contour analysis, as well as filtration and capillary pressure tests according to VDI guidelines. The tomography measurements provide microscopic information about the porous system, quantified using characteristic key parameters and distribution functions. | |
Project title | Development of process models based on 3D information about the multiphase processes in the pore space of a filter cake (DFG PE 1160/23-1) |
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