Hydrodynamics and mass transfer coefficients in a bubble column photo-bioreactor

• Published in: Chemical engineering science 2017-08, Vol.168, p.55-66
• Main Authors: Manjrekar, Onkar N., Sun, Yujian, He, Lian, Tang, Yinjie J., Dudukovic, Milorad P.
• Format: Article
• Language: English
• Subjects: Bubble column photo-bioreactor; Bubble velocity; Gas holdup; Gas-liquid interfacial area; Volumetric mass transfer coefficient
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/j.ces.2017.04.016

•Use of a 4-point optical probe in a photo-bioreactor.•The Impact of cell culture medium and micro algae cell density on hydrodynamics.•A new model is developed for determination of volumetric mass transfer coefficient.•Impact of changes in hydrodynamics on volumetric coefficients is described. The present study compares typical measurements of bubble dynamics obtained with a 4-point optical probe over the same range of superficial gas velocity in the same size gas–liquid contactor in two different systems. The classical bubble column (BC) arrangement employed air bubbled through water. The photo-bioreactor (PBR) used a growing algae in appropriate culture solution. Local gas holdup distribution across the vessel was monitored, as well as the local distribution of bubble velocity, bubble chord length, bubble frequency and interfacial area per unit volume for both systems. It was observed these parameters were significantly different in the photo-bioreactor. This information coupled with the tracer absorption studies with oxygen provided the needed information to evaluate the gas liquid volumetric mass transfer coefficients from an appropriate model for both systems. The development of such a model is described. It was concluded that the difference in hydrodynamics of the two systems was due to difference in physicochemical properties.