This work examined the mass transfer efficiency of a rotating packed bed with various radii of the packed bed. Experimental results showed that k L a increased with decreasing volume of the packed bed. This may contribute to the significant end effects as the volume of the packed bed is reduced. A correlation which takes end effects into consideration for k L a in a rotating packed bed was proposed and is valid for different sizes of the rotating packed bed and for viscous Newtonian and non-Newtonian liquid systems. In addition, it was also found that the correlation could reasonably estimate most of the k L a data in the Higee literature.

This work investigated the mass transfer of a rotating packed bed (RPB) with emphasis on the effects of the packing's size, shape, material, and surface property. Experimental results show that there is no obvious relationship between a t and k L a. Among the various shapes of the packings, the mass transfer coefficients of Raschig rings and Intalox saddles are lower than those of the others, while the k L a of the wire meshes is the highest. As to materials, the mass transfer coefficients are similar for acrylic, glass, ceramic, and stainless steel beads. Besides, the k L a values of the hydrophobically treated packings are 8−27% lower than those of the original glass and ceramic packings. A modified correlation of k L a, which includes the effects of various packings, is proposed based on our RPB experimental results. Further, this correlation can also reasonably estimate most of the k L a data in the Higee literature.

The mass transfer (stripping of ethanol) and pressure drop (water−air) of a rotating packed bed were investigated under 13−273 equiv of gravitational force with two packings. The results indicated that the mass-transfer coefficient (K G a) was enhanced due to the centrifugal force as compared to a conventional packed bed. An empirical correlation was also proposed, suggesting that the K G a value depends on the Gr G number to the power of 0.25. As to pressure drop, the gas rate seems to be a more important factor than the liquid rate because of less liquid holdup under centrifugal force. A semiempirical equation was also developed to correlate the pressure drop data with good agreement.

A Higee absorption process was developed to remove VOCs (volatile organic compounds) from air into an aqueous phase under a centrifugal field. The experimental results showed that the overall volumetric gas-phase mass-transfer coefficient (K G a) increased as a function of the gas Grashof number (Gr G ) to the power of 0.18. In analyzing k G and a individually, it was found that the enhancement of mass transfer by the centrifugal force can mainly be attributed to an increase in the effective gas-liquid interfacial area. The values of k G lie in a range similar to that for conventional packed beds.