Evaluation of fine particulate matter removal efficiency by water spraying on packing materials: Influence of shape and size

Abstract

This study systematically evaluated the effects of various shapes and sizes of packing materials on fine dust removal efficiency. Unlike previous studies focused on improving scrubber technology, this research explored how the physical properties of packing materials contribute to particle removal. A total of 16 different shapes of packing materials with diameters of 6 mm and 10 mm were used and categorized into four groups: sphere, hollow sphere, Raschig ring, and Pall ring. A packed bed system was constructed using these packing materials, and the correlation between the geometric shape of the packing materials and particle removal efficiency was evaluated. A peak particle removal efficiency of 95.3 % was observed with the 6 mm sphere packing material, while the highest quality factor of 0.02411 Pa-1 was achieved with the 6 mm hollow sphere packing material. The Pall ring also demonstrated high efficiency. Overall, the Pall ring packing material with a 6 mm diameter showed the best performance, with a particle removal efficiency of 83.4 % and a quality factor measured at 0.02319 Pa-1. To better characterize the geometric features of the packing materials, a novel equation for calculating characteristic length was proposed, which was found to exhibit a strong correlation with particle removal efficiency in packed bed systems filled with various packing materials. The relationship between the Stokes number and the Reynolds number was derived, resulting in a correlation equation with a high coefficient of determination (R2 = 0.8728), which closely matched the experimental data for the different packing materials. The correlation equation derived in this study is expected to be highly useful in developing packing material shapes optimized for efficient packed bed systems designed for particle removal. These findings provide a solid framework for improving packed bed systems in diverse applications, offering detailed guidelines for enhancing particle removal efficiency and optimizing geometric design.