The Effect of Packing on Mass Transfer in a Rotating Packed Bed
Date Issued
2004
Date
2004
Author(s)
Lin, Fang-Yi
DOI
zh-TW
Abstract
Abstract
In this study, the packing effect in rotating packed bed was investigated. The mass transfer coefficients (kLa) were obtained for deoxygenation from water by nitrogen stream. Random packings were used with the variation in sizes, materials, shapes, surface properties together with some structured packings.
According to the experimental results, there was no obvious strong relationship between packing specific surface area and mass transfer coefficient. As to materials, ceramic packings had superior mass transfer efficiency. And probably because the shape of Raschig rings and saddle type might hinder liquid distribution, the mass transfer efficiency of spherical packings was higher than those of Raschig rings and saddle type. Besides, the kLa values for hydrophilic packings were generally higher by about 11%~43% than those of hydrophobic packings. Moreover, the mass transfer of wire mesh was better than that of blades and steel rings.
We proposed a so-called packing factor to correct the mass transfer coefficient due to the discrepancy among experimental data. However, there is no obvious relationship between packing factors and packing characteristics, including specific surface area, porosity and hydraulic diameter. Furthermore, we developed preliminary film flow model and droplet flow model to investigate how rotor speed and packing characteristics influence flow pattern within rotating packed bed. Also, we analyzed the contribution of film flow and droplet flow to mass transfer in the rotating packed bed.
Based on experimental and theoretical results, the superior performance of packings could be obtained with the hydrophilic surface for enhancing mass transfer caused by film flow and the conformation of breaking liquid into smaller droplets that raise effective interfacial area.
Subjects
旋轉填充床
填充物
質傳
Rotating packed bed
packing
mass transfer
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-93-R92524026-1.pdf
Size
23.53 KB
Format
Adobe PDF
Checksum
(MD5):0f57f1d815f635a4295c14cc1b8e3bc3