Abstract
The draft tube configuration significantly affected the performance of an airlift contactor. The multiple draft tube configuration was demonstrated to give a better gas-liquid mass transfer when compared with a conventional one-draft-tube system. The airlift with a larger number of draft tubes allowed a higher level of bubble entrainment, which rendered a high downcomer gas holdup. This resulted in a higher overall gas holdup in the contactor. Liquid velocity was also enhanced by increasing the number of draft tubes. The ratio between downcomer and riser cross sectional areas, A d /A r , had a great effect on the system performance, where a larger A d /A r led to a lower downcomer liquid velocity and smaller quantity of gas bubbles being dragged into the downcomer. This resulted in low gas holdup, and consequently, low gas-liquid interfacial mass transfer area, which led to a reduction in the overall volumetric mass transfer coefficient. The presence of salinity in the system drastically reduced the bubble size and subsequently led to an enhancement of gas entrainment within the system. As a result, higher gas holdups and gas-liquid interfacial area were observed, and hence, a higher rate of gas-liquid mass transfer was obtained.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Al-Masry, W. A., “Effects of antifoam and scale-up on operation of bioreactors,” Chem. Eng. Process, 38, 197 (1999).
Blažej, M., Kiša, M. and Markoš, J., “Scale influence on the hydrodynamics of an internal loop airlift reactor,” Chem. Eng. Process, 43, 1519 (2004).
Camacho, F.G., Grima, E. M., Mirón, A. S., Pascual, V.G. and Chisti, Y., “Carboxymethyl cellulose protects algal cells against hydrodynamic stress,” Enzyme and Microbial Technology, 29, 602 (2001).
Choi, K. H., Chisti, Y. and Moo-Young, M., “Comparative evaluation of hydrodynamic and gas-liquid mass transfer characteristics in bubble column and airlift slurry reactors,” Chem. Eng. J., 62, 223 (1996).
Gopal, J. S. and Sharma, M. M., “Hydrodynamic and mass transfer characteristics of bubble and packed bubble columns with downcomer,” Can. J. Chem. Eng., 60, 353 (1982).
Heijnen, J. J., Hols, J., van der Lans, R.G. J.M., van Leeuwen, H. L. J.M., Mulder, A. and Weltevrede, R., “A simple hydrodynamic model for the liquid circulation velocity in a full-scale two-and three-phase internal airlift reactor operating in the gas recirculation regime,” Chem. Eng. Sci., 52(15), 2527 (1997).
Jianping, W., Xiaoqiang, J., Lei, P., Changlin, W. and Guozhu, M., “Nitrifying treatment of waste water from fertilizer production in a multiple airlift loop bioreactor,” Biochem. Eng. J., 25, 33 (2005).
Koide, K., Iwamoto, S., Takasaka, Y., Matsuura, S., Takahashi, E. and Kimura, M., “Liquid circulation, gas holdup and pressure drop in bubble column with draught tube,” J. Chem. Eng. Jpn., 17(6), 611 (1984).
Krichnavaruk, S., Loataweesup, W., Powtongsook, S. and Pavasant, P., “Optimal growth conditions and the cultivation of Chaetoceros calcitrans in airlift photobioreactor,” Chem. Eng. J., 105, 91 (2005).
Merchuk, J. C., Ladwa, N., Cameron, A., Bulmer, M. and Pickett, A., “Concentric-tube airlift reactors: effects of geometrical design on performance,” AIChE J., 40(7), 1105 (1994).
Mirón, A. S., Garć, M. C. C., Gómez, A. C., Camacho, F.G., Grima, E. M. and Chisti, Y., “Shear stress tolerance and biochemical characterization of Phaeodactylum tricornutum in quasi steady-state continuous culture in outdoor photobioreactors,” Biochem. Eng. J., 16, 287 (2003).
Prince, M. J. and Blanch, H.W., “Transition electrolyte concentrations for bubble coalescence,” AIChE J., 36(9), 1425 (1990).
Russell, A. B., Thomas, C. R. and Lilly, M.D., “The influence of vessel height and top-section size on the hydrodynamic characteristics of airlift fermentors,” Biotech. Bioeng., 43, 69 (1994).
Shamlou, P. A., Pollard, D. J. and Ison, A. P., “Volumetric mass transfer coefficient in concentric-tube airlift bioreactors,” Chem. Eng. Sci., 50(10), 1579 (1995).
Silapakul, S., Powtongsook, S. and Pavasant, P., “Nitrogen compounds removal in a packed bed external loop airlift bioreactor,” Korean J. Chem. Eng., 22, 393 (2005).
Wongsuchoto, P. and Pavasant, P., “Internal liquid circulation in annulus sparged internal loop airlift contactors,” Chem. Eng. J., 100, 1 (2004).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Tunthikul, N., Wongsuchoto, P. & Pavasant, P. Hydrodynamics and mass transfer behavior in multiple draft tube airlift contactors. Korean J. Chem. Eng. 23, 881–887 (2006). https://doi.org/10.1007/s11814-006-0003-5
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s11814-006-0003-5