| Titre : | Mass transfer in a viscous bubble column with forced oscillations (2008) |
| Auteurs : | Y. G. Waghmare, Auteur ; Richard G. Rice, Auteur ; F Carl Knopf, Auteur |
| Type de document : | Article : texte imprimé |
| Dans : | Industrial & engineering chemistry research (Vol. 47 n°15, Août 2008) |
| Article en page(s) : | p. 5386-5394 |
| Note générale : | Bibliogr. p. 5394 |
| Langues : | Anglais |
| Tags : | Viscous bubble column ; Oscillations -- mass transfer ; carboxymethylcellulose solutions |
| Résumé : | Previously, it was shown that low-amplitude (0.5−2.5 mm) oscillations at moderate frequencies (0−25 Hz) can be used to improve bubble column performance. Literature on pulsed-flow bubble columns has mainly focused on air−water systems. In the present work, the effects of oscillations on mass transfer in a pulsed-flow bubble column were studied for various carboxymethylcellulose solutions giving an effective viscosity range of 1−62 cP. As in our previous work on air−water systems, the viscous system exhibits an initial increase in mass-transfer coefficient as a function of frequency and then leveled to a plateau. This asymptotic behavior can be attributed to the Bjerknes force acting on a bubble, which slows the bubble rise as frequency is increased. The shape of the curve for mass-transfer coefficient vs frequency was unchanged for viscous systems, but the absolute value of the mass-transfer coefficient decreased as a function of increasing viscosity. A theory was developed from first principles to show how the volumetric mass-transfer coefficient changes as a function of operating parameters, such as the frequency and amplitude of vibrations, gas superficial velocity, and viscosity of the fluid. The comparison with experiments was quite good for a large range of velocities and viscosities. |
| En ligne : | http://pubs.acs.org/doi/abs/10.1021/ie800041k |
