Abstract
In fermentation processes, a constant supply of oxygen is fundamental for cell growth. The supply rate is controlled by the volumetric mass transfer coefficient. The literature reports few numerical studies evaluating the volumetric mass transfer coefficient for aerated systems with non-Newtonian fluids in stirred tanks. The aim of this work was to undertake a numerical study of the main hydrodynamic and mass transfer parameters, including average gas hold-up, and power number. Xanthan gum solutions were used to simulated. The simulations were performed with different impeller rotational speeds (600 to 1000 revolution per minute) and specific gas flow rates (0.4 to 1.2 volume of gas per volume of liquid per minute), adopting an Euler-Euler approach and assuming uniform spherical bubbles. The turbulence was simulated with k−ε turbulence model and sst shear stress transport turbulent model. The numerical results were compared with experimental values available in the literature. The results showed good agreement between the numerical and experimental values of gas hold-up, power number, and volumetric mass transfer coefficient. The sst shear stress transport turbulence model provided better results, compared to the standard k−ε model, for simulation of volumetric mass transfer coefficient in a non-Newtonian fluid under the conditions used. Simulations for uniform bubbles with 3 millimeters diameter gave mass transfer coefficient values that were close to the experimental data.
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References
Amanullah, A., Hjorth, S.A., and Nienow, A.W., Cavern sizes generated in highly shear thinning viscous fluids by SCABA 3SHP1 impellers, Food Bioprod. Process., 1997, vol. 75, p. 232.
García-Ochoa, F., Gómez Castro, E., and Santos, V.E., Oxygen transfer and uptake rates during xanthan gum production, Enzyme Microb. Technol., 2000, vol. 27, p. 680.
García-Ochoa, F. and Gómez, E., Mass transfer coefficient in stirred tank reactors for xanthan gum solutions, Biochem. Eng. J., 1998, vol. 1, p. 1.
Badino, A.C., Facciotti, M.C.R., and Schmidell, W., Volumetric oxygen transfer coefficients (k La) in batch cultivations involving non-Newtonian broths, Biochem. Eng. J., 2001, vol. 8, p. 111.
Carbajal, R.I. and Tecante, A., On the applicability of the dynamic pressure step method for kLa determination in stirred Newtonian and non-Newtonian fluids, culture media and fermentation broths, Biochem. Eng. J., 2004, vol. 18, p. 185.
García-Ochoa, F. and Gómez, E. Bioreactor scale-up and oxygen transfer rate in microbial processes: an overview, Biotechnol. Adv., 2009, vol. 27, p. 153.
Chhabra, R.P. and Richardson, J.F., Non-Newtonian Flow in the Process Industries, Oxford: Butterworth–Heinemann, 1999.
Corrêa, L., Badino, A.C., and Cruz, A.J.G., Mixing design for enzymatic hydrolysis of sugarcane bagasse: methodology for selection of impeller configuration, Bioprocess Biosyst. Eng., 2016, vol. 39, p. 285. doi 10.1007/s00449-015-1512-6
Campesi, A., Cerri, M.O., Hokka, C.O., and Badino, A.C., Determination of the overall shear rate in a stirred and aerated tank bioreactor, Bioprocess Biosyst. Eng., 2009, vol. 32, p. 241.
Bustamante, M.C.C., Cerri, M.O., and Badino, A.C., Comparison between overall shear rate in conventional bioreactor with Rushton and Elephant ear impellers, Chem. Eng. Sci., 2013, vol. 90, p. 92.
Gogate, P.R., Beenackers, A.A.C.M., and Pandit, A.B., Multiple-impeller systems with a special emphasis on bioreactors: a critical review, Biochem. Eng. J., 2000, vol. 6, p. 109.
Gabelle, J.C., Augier, F., Carvalho, A., Rousset, R., and Morchain, J., Effect of tank size on kLa and mixing time in aerated stirred reactors with non-Newtonian fluids, Can. J. Chem. Eng., 2011, vol. 89, p. 1139.
Xie, M.-H., Xia, J.-Y., Zhou, Z., Zhou, G.-Z., Chu, J., Zhuang, Y.-P., Zhang, S.-L., and Noorman, H., Power consumption, local and overall volumetric mass transfer coefficient in multiple-impeller stirred bioreactors for xanthan gum solution, Chem. Eng. Sci., 2014, vol. 106, p. 144.
Venneker, B.C.H., Derksen, J.J., and van den Akker, H.E.A., Population balance modeling of aerated stirred vessels based on CFD, AIChE J., 2002, vol. 48, p. 673.
Moilanen, P., Laakkonen, M., and Aittamaa, J., Modeling aerated fermenters with computational fluid dynamics, Ind. Eng. Chem. Res., 2006, vol. 45, p. 8656.
Laakkonen, M., Moilanen, P., Alopaeus, V., and Aittamaa, J., Dynamic modeling of local reaction conditions in an agitated aerobic fermenter, AIChE J., 2006, vol. 52, p. 1673.
Moilanen, P., Laakkonen, M., Visuri, O., and Aittamaa, J., Modeling local gas–liquid mass transfer in agitated viscous shear-thinning dispersions with CFD, Ind. Eng. Chem. Res., 2007, vol. 46, p. 7289.
Moilanen, P., Laakkonen, M., Visuri, O., Alopaeus, V., and Aittamaa, J., Modeling mass transfer in a aerated 0.2 m3 vessel agitated by Rushton, Phasejet and Combijet impellers, Chem. Eng. J., 2008, vol. 142, p. 95.
Duan, S., Yuan, G., Zhao, Y., Ni, W., Luo, H., Shi, Z., and Liu, F., Simulation of computational fluid dynamics and comparison of cephalosporin C fermentation performance with different impeller combinations, Korean J. Chem. Eng., 2013, vol. 30, p. 1097.
Vlaev, S.D., Martinov, M., Pavlova, K., Russinova-Videva, S., and Georgiva, K., Characterization of NSimpeller mixing in viscous batches containing exopolysaccharides, Proc. 14th Eur. Conf. on Mixing, Warsaw, 2012, p. 10.
Gezork, K.M., Bujalski, W., Cooke, M., and Nienow, W., The transition from homogeneous to heterogeneous flow in a gassed, stirred vessel, Chem. Eng. Res. Des., 2000, vol. 78, p. 363.
Parthasarathy, R. and Ahmed, N., Bubble size distribution in a gas sparged vessel agitated by a Rushton turbine, Ind. Eng. Chem. Res., 1994, vol. 33, p. 703.
Gimbun, J., Rielly, C.D., Nagy, Z.K., and Derksen, J.J., Detached eddy simulation on the turbulent flow in a stirred tank, AIChE J., 2012, vol. 58, p. 3224.
Bakker, A. and Fasano, J.B., A computational study of flow pattern in an industrial paper pulp chest with a side entering impeller, Proc. AIChE Annual Meeting, Miami Beach, Fla., 1992, p. 118.
Bustamante, M.C.C., Transferência de oxigênio e condições de cisalhamento em biorreactor convencional com impelidor orelha de elefante, PhD Thesis, São Carlos, Brazil: Federal Univ. of São Carlos, 2013.
Khopkar, A.R., Rammohan, A.R., Ranade, V.V., and Dudukovic, M.P., Gas–liquid flow generated by a Rushton turbine in stirred vessel: CARPT/CT measurements and CFD simulations, Chem. Eng. Sci., 2005, vol. 60, p. 2215.
Kawase, Y., Halard, B., and Moo-Young, M., Liquidphase mass transfer coefficients in bioreactors, Biotechnol. Bioeng., 1992, vol. 39, p. 1133.
ANSYS Inc. 15.0 FLUENT, User’s Guide.
Kulkarni, A.L. and Patwardhan, A.W., CFD modeling of gas entrainment in stirred tank systems, IChemE, 2014, vol. 92, p. 1227.
Bhattacharya, S., Hebert, D., and Kresta, S.M., Air entrainment in baffled stirred tanks, IChemE, 2007, vol. 85, p. 654.
Skelland, A.P.H., Mixing and agitation of non-Newtonian fluids, in Handbook of Fluids in Motion, Cheremisinoff, N.P. and Gupta, R., Eds., Ann Arbor, Mich.: Ann Arbor Science, 1983.
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Valverde, M.R., Bettega, R. & Badino, A.C. Numerical evaluation of mass transfer coefficient in stirred tank reactors with non-Newtonian fluid. Theor Found Chem Eng 50, 945–958 (2016). https://doi.org/10.1134/S0040579516060178
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DOI: https://doi.org/10.1134/S0040579516060178