Optical Investigations Into Wetted Commercial Coalescence Filter Using 3d Micro-Computer-Tomography

Coalescence filtration is used in a variety of process industries to remove liquid mists from gas flows. Non-woven materials are widely used due to their high separation efficiency and low cost. The operating conditions of these filters are dependent on the internal structure of the filter material. Inhomogeneities, arising from the manufacturing process, not only affect the flow of air through the filter but also determine which areas are preferentially wetted, and in turn modify the airflow through the blocked regions. This study uses three-dimensional (3D) micro-computer-tomography imaging to analyze, in a non- destructive manner, the internal structure of a commercial coalescence filter, made of oleophilic glass fibres in dry and wetted state. Using image processing software, a post-processing routine is developed to identify filter parameters based on coarse spatially-resolved images. Afterwards, the dry-filter images are compared with wetted-filter images to establish that inhomogeneous local solidity is responsible for inhomogeneous wetting in an oleophilic filter. (C) 2021 Elsevier Ltd. All rights reserved.