Abstract
The hydrodynamics of biotechnological processes is complex. So far, few studies were made with bioreactors of the airlift type with an enlarged degassing zone.
In this work, the influence of solids loading, solids specific gravity and draught tube dimensions on mixing and circulation times and critical air flow rate for an internal loop airlift bioreactor with an enlarged sedimentation/degassing zone is studied.
The results indicate that the critical air flow rate as well as the mixing time increase with an increase in solids loading in the bioreactor. Circulation time presents a maximum for a solids load between 5 and 10% (v/v). It is also shown that small variations in solids specific gravity, for values close to that of the liquid, have a significant influence on the critical air flow rate and on the mixing time.
An optimal (minimal) value for the circulation time and for the critical air flow rate was obtained for a riser to down comer diameter ratio of 0.46. The minimum mixing time was obtained for a riser to down comer height ratio of 0.80.
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References
Choi, P.B.: Designing Airlift Loop Fermenters. Chem. Eng. December (1990) 32–37
Chen, N.Y.; Kondis, E.F.; Srinivasan, S.: Low Pressure Airlft Fermenter for Single Cell Protein Production: I. Design and Oxygen Transfer Studies. Biotechnol. Bioeng. 29 (1987) 414–420
Sousa, M.L.; Teixeira, J.A.; Mota, M.: Comparative Analysis of Ethanolic Fermentation in Two Continuous Flocculation Bioreactors and Effect of Flocculation Addition, Bioprocess Engng. 11 (1994) 83–90
Tijuis, L.; Loosdrecht, M.C.M. van; Heijnen, J.J.: Formation and Growth of Heterotrophic Aerobic Biofilms on Small Suspended Particles in Airlift Reactors. Biotechnol. Bioeng. 44 (1994) 595–608
Siegel, Marc; Merchuk, J.C.: Hydrodynamics in Rectangular Airlift Reactors: Scale-up and the Influence of Gas-Liquid Separator Design. Can. J. Chem. Eng. 69 (1991) 465–473
Sukan, A.A.; Vardar-Sukan, F.: Mixing Performance of Airlift Fermenters Against Working Volume and Draft Tube Dimensions. Bioprocess Engng. 2 (1987) 33–38
Kennard, M.; Janekeh, M.: Two- and Three-Phase Mixing in a Concentric Tube Gas-Lift Fermentor. Biotechnol. Bioeng. 38 (1991) 1261–1270
Fraser, R.D.; Hill, G.A.: Hydrodynamic Characteristics of a Spining Sparger, External Loop Airlift Bioreactor. Can. J. Chem. Eng. 71 (1993) 419–425
Prasad, K.Y.; Ramanujam, T.K.: Liquid Circulation Velocity and Overall Gas Holdup in a Modified Jet Lop Bioreactor with Low SPECIFIC GRAVITY Particles. Bioprocess Engng. 10 (1994) 131–137
Merchuk, J.C.; Ladwa, N.; Cameron, A.; Bulmer, M.; Pickett, A.:Concentric-Tube Airlift Reactors: Effects of Geometrical Design on Performance. AIChE J. 40 (1994) 1105–1117
Moresi, M.: Optimal Design of Airlift Fermenters. Biotechnol. Bioeng. 23 (1981) 2537–2560
Siegel, M.H.; Merchuk, J.C.; Schugerl, K.: Airlift Reactor Analysis: Interrelationships Between Riser, Downcomer, and Gas-Liquid Separator Behavior, Including Gas Recirculation Effects. AIChE J. 32 (1986) 1585–1596
Thomas, N.H.; James, D.A.: Fluid Dynamic Considerations in Airlift Bioreactors. Biotech. Proc. 60–71
Livingston, A.G.; Zhang, S.F.: Hydrodynamic Behaviour of Three-Phase (Gas-Liquid-Solid) Airlift Reactors. Chem. Eng. Sci. 48 (1993) 1641–1654
Siegel, M.H.; Hallaile, M.; Herskowitz, M.; Merchuk, J.C.: Hydrodynamics and Mass Transfer in a Three-Phase Airlift Reactor. In: R. King (ed.): 2nd. International Conference on Bioreactor Fluid Dynamics, pp. 21–23, 1988
Weiland, P.: Influence of Draft Tube Diameter on Operation Behaviour of Airlift Loop Reactors. Ger. Chem. Eng. 7 (1984) 374–385
Favre, E.; Deront, M.; Péringer, P.: Influence of a Rotating Sieve on Pumping and Mixing Performances of an Internal Loop Reactor. Bioprocess Engng. 11 (1994) 91–95
Russel, A.B.; Thomas, C.R.; Lilly, M.D.: The influence of the Vessel Height and Top-Section Size on the Hydrodynamic Characteristics of Airlift Fermentors. Biotechnol. Bioeng. 43 (1994) 69–76
Lu, Wen-Jang; Hwang, Shyh-Jye: Liquid Mixing in Internal Loop Airlift Reactors. Ind. Eng. Chem. Research 33 (1994) 2180–2186
Assa, A.; Bar, R.: Biomass Axial Distribution in Airlift Bioreactor with Yeast and Plant Cells. Biotechnol. Bioeng. 38 (1991) 1325–1330
Kawase, Y.; Omori, N.; Tsujimura, M.: Liquid-Phase Mixing in External Loop Airlift Bioreactors. J. Chem. Tech. Biotechnol. 61 (1994) 49–55
Gianetto, A.; Ruggeri, B.; Specchia, V.; Sassi, G.; Forna, R.: Continuous Extraction Loop Reactor (CELR): Alcoholic Fermentation by Fluidized Entrapped Biomass. Chem. Eng. Sci. 43 (1988) 1891–1896
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This work was supported by J.N.I.C.T. (Junta Nacional de Investigação Cientifica e Tecnológica).
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Vicente, A.A., Teixeira, J.A. Hydrodynamic performance of a three-phase airlift bioreactor with an enlarged degassing zone. Bioprocess Engineering 14, 17–22 (1995). https://doi.org/10.1007/BF00369848
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DOI: https://doi.org/10.1007/BF00369848