3D X-ray tomographic microstructure analysis of dust-clogging inside nonwoven fibrous filter media

Abstract

Clogging inside fibrous filter media largely affects the particle loading characteristics of filter media. The three-dimensional (3D) analysis of particle deposits that form clogging is thus necessary. Compact nonwoven fibrous filter media with thick-fiber was fabricated using meltblown technology. Filter media with the deposited dust mass was scanned with X-ray μ-CT imaging. Methodology of image processing and image analysis was developed to open the black box of loaded fibrous filter media. Quantitative microstructure analysis was conducted including pristine fibrous structure analysis, quadrant structure analysis, depth distribution of particles, and size distribution of 3D particle deposits. Quadrant analysis revealed that deposited dust mass was negatively correlated with quadrant fiber solidity. A considerably large volume of particle deposits formed face-region (in the depth of 0–200 μm) clogging inside the filter structure. Higher-basis-weight filter media exhibited more particle deposition in deeper filter depth. Watershed-segmentation-based size distribution statistics revealed that more volume of large connected particle agglomerates and larger constituent individual particles existed inside higher-basis-weight filter media.