Airlift bioreactor for biological applications with microbubble mediated transport processes

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AL-Mashhadani, M.K.H. ; Wilkinson, S.J. ; Zimmerman, W.B. (2015)
  • Publisher: Elsevier
  • Journal: Chemical Engineering Science (issn: 0009-2509, vol: 137, pp: 243-253)
  • Related identifiers: doi: 10.1016/j.ces.2015.06.032
  • Subject: Applied Mathematics | Chemistry(all) | Chemical Engineering(all) | Industrial and Manufacturing Engineering

Airlift bioreactors can provide an attractive alternative to stirred tanks, particularly for bioprocesses with gaseous reactants or products. Frequently, however, they are susceptible to being limited by gas–liquid mass transfer and by poor mixing of the liquid phase, particularly when they are operating at high cell densities. In this work we use CFD modelling to show that microbubbles generated by fluidic oscillation can provide an effective, low energy means of achieving high interfacial area for mass transfer and improved liquid circulation for mixing.\ud \ud The results show that when the diameter of the microbubbles exceeded 200 µm, the “downcomer” region, which is equivalent to about 60% of overall volume of the reactor, is free from gas bubbles. The results also demonstrate that the use of microbubbles not only increases surface area to volume ratio, but also increases mixing efficiency through increasing the liquid velocity circulation around the draft tube. In addition, the depth of downward penetration of the microbubbles into the downcomer increases with decreasing bubbles size due to a greater downward drag force compared to the buoyancy force. The simulated results indicate that the volume of dead zone increases as the height of diffuser location is increased. We therefore hypothesise that poor gas bubble distribution due to the improper location of the diffuser may have a markedly deleterious effect on the performance of the bioreactor used in this work.
  • References (40)
    40 references, page 1 of 4

    AL-Mashhadani, M.K.H, Bandalusena, H.C.H., Zimmerman, W.B., 2012. CO2 mass transfer induced through an airlift loop by a microbubble cloud generated by fluidic oscillation. Ind. Eng. Chem. Res. 51 (4), 1864-1877.

    Becker, S., Sokolichin, A., Eigenberger, G., 1994. Gas-liquid flow in bubble columns and loop reactors: Part II. Comparison of detailed experiments and flow simulations. Chem. Eng. Sci. 49, 5747-5762.

    Bello-Mendoza, R., Sharratt, P.N., 1998. Modelling the effects of imperfect mixing on the performance of anaerobic reactors for sewage sludge treatment. J. Chem. Technol. Biotechnol. 71, 121-130.

    Calvo, E.G., Letón, P., 1991. A fluid dynamic model for bubble columns and airlift reactors. Chem. Eng. Sci. 46, 2947-2951.

    Calvo, E.G., 1989. A fluid dynamic model for airlift loop reactors. Chem. Eng. Sci. 44, 321-323.

    Calvo, E.G., Letón, P., Arranz, M.A., 1991. Prediction of gas hold up and liquid velocity in airlift loop reactors containing highly viscous Newtonian liquids. Chem. Eng. Sci. 46, 2951-2954.

    Chisti, M.Y., 1989. Airlift Bioreactor. Elsevier Applied Science, London, UK.

    Huang, Q., Yang, C., YU, G., Mao, Z.-S., 2010. CFD simulation of hydrodynamics and mass transfer in an internal airlift loop reactor using a steady two-fluid model. Chem. Eng. Sci. 65, 5527-5536.

    Karim, K., Haffmann, R., Klasson, K.T., Al-Dahhan, M.H., 2005. Anaerobic digestion of animal waste: effect of mode of mixing. Water Res. 30 (15), 3597-3606.

    Karim, K., Klasson, K.T., Hoffmann, R., Dresher, S.R., Depaoi, D.W., Al-Dahhan, H., 2003. Anaerobic digestion of animal waste: effect of mixing. Energ. Environ-UK 7 (359), 175-185.

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