Simulation of performance of fibrous filter media composed of cellulose and synthetic fibers

Abstract

Fibrous filter media with reticular support structure and tortuous pore channels have been widely used in filtration fields. Most of these filter media contain multiple types of fibers such as wood pulp fibers, glass fibers or synthetic fibers with a broad range of diameters to meet the requirements of filtration and strength performance. Some fibers in the filter media, e.g. cellulose fibers, have complex and irregular shapes such as hollow structure. It is necessary to generate a more realistic filter media model based on the actual properties of fibers. In this work, fibrous filter media with complex microstructure were investigated by simulation method. SEM (scanning electron microscope) and fiber analyzer were used to obtain the physical characteristics of fiber such as diameter, wall thickness, length Gaussian distributions, and cross-section shape. Based on these experimental data, a database containing several common fiber models was created. 3-D fibrous models corresponding to the real wet-laid binderless filter media were generated. Average pore size, permeability and collection efficiency simulations were carried out using the modules of the GeoDict code. The simulated results were close to the experimental data. With the work of this study, it was found that smaller diameter PET fibers in the filter media led to a lower average pore size, lower permeability and a better collection performance. When the diameter of PET fibers was < 5.54 μm, the change in fiber diameter has a great impact on the performance. When the diameter of PET fibers was larger than 12.40 μm, it has less effect on the performance.