Fenómenos de transporte

 

Características de la hidrodinámica de un biorreactor industrial tipo tanque agitado

 

Hydrodinamic characteristics of the industrial stirred tank bioreactor

 

J. Raffo-Durán¹*, A. Figueredo-Cardero¹ y J.C. Dustet-Mendoza²

 

¹ Centro de Inmunología Molecular. Calle 216 esq 15a, Reparto Atabey, Playa, CP 11600. La Habana, Cuba. * Autor para la correspondencia. E-mail: jordan@cim.sld.cu Tel. +53-53-83-56-36, Fax 00-00-00-00..

² Instituto Superior Politécnico "José Antonio Echeverría", CUJAE, Facultad de Ingeniería Química. Calle 114 No. 11901 entre, Ciclovía y Rotonda, Marianao, CP 19390. La Habana, Cuba.

 

Recibido 12 de Diciembre de 2013.
Aceptado 28 de Junio de 2014.

 

Resumen

Este trabajo se propone el uso de la Dinámica de Fluidos por vía Computacional (DFC) y la experimentación para satisfacer las necesidades del conocimiento sobre los patrones de flujos y de otras magnitudes relacionadas con los mismos en un biorreactor industrial tipo tanque agitado para el cultivo de células animales, obteniéndose información sobre la hidrodinámica mediante la manipulación de los parámetros de operación flujo de aire y velocidad de agitación. Se propone un modelo matemático, usando la herramienta de DFC, obteniéndose con el mismo los campos de velocidades comparables con los informados en la literatura para un biorreactor con la misma geometría que el estudiado. Por la vía experimental fueron determinados el tiempo de mezclado y la distribución de tiempos de residencia (DTR) en la condición de operación del biorreactor (sin usar aireación), obteniéndose un patrón de flujo de mezcla perfecta piara la fase líquida. Además se determinó el tiempo de mezclado mediante la DFC alcanzándose una buena aproximación con el obtenido experimentalmente. Se caracterizó la operación del biorreactor usando aire mediante un diseño experimental factorial 3² y se obtuvo que el coeficiente volumétrico de transferencia de oxígeno (K_La) depende de las variables velocidad de agitación (N) y flujo de aire (Qa). Haciendo uso de correlaciones publicadas en la literatura se concluyó que en la condición de operación ocurre el fenómeno de inundación del impelente.

Palabras clave: biorreactor, tanque agitado, DFC, transferencia de masa gas-líquido, inundación del impelente, dispersión gas-liquido.

 

Abstract

This paper proposes the use of Computational Fluid Dynamics (CFD) to gain insight into the on flow patterns and other variables related to them in the industrial bioreactor for animal cell culture, and experimentation and to obtain information on the hydrodynamics by handling of the air flow and agitation operating parameters. We propose a mathematical model using the CFD tool, with which velocity fields comparable to those reported in the literature for a bioreactor with the same geometry as the one studied were obtained. By experimentation the time of mixing and the residence time distribution (RTD) were determined in the operating condition of the bioreactor (without aeration), and a flow pattern of perfect mix for the liquid phase was obtained. Also the mixing time was determined by CFD reaching a good approximation to that obtained experimentally. The operation of the bioreactor with air was characterized using a factorial experimental design 3² and the results obtained showed that the coefficient of volumetric oxygen transfer (K_La) depends on the variables stirring speed (N) and air flow rate (Qa).Using published correlations in the literature it was concluded that the phenomenon of flooding of the impeller occurs in the operating condition.

Keywords: bioreactor, stirred tank, CFD, gas-liquid mass transfer, flooding of the impeller, gas-liquid dispersing.

 

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