Hydrodynamic Study of Bubbles in a Bubble Column Reactor Part II – Numerical Study

Abstract:

The present work deals with the use of CFD analysis and the validation of the experimental work carried out on the artificial splitting of an air bubble in a bubble column reactor. In Part I of this work, artificial splitting of bubble in a bubble column rector is experimentally studied by using a high speed camera. Image processing technique was used to identify bubble size and bubble velocity. In present work CFD simulations are carried out using ANSYS FLUENT software using Volume of Fluids (VOF) method. VOF is based on a surface tracking technique applied to a fixed Eulerian space. The phase fraction in physical quantities that can be used to distinguish the distribution of gas hold up in a bubble Column reactor. The numerical study of splitting of bubble into two bubbles of nearly equal size is considered. In the bubble column reactor, the liquid phase is stationary and gas flow rate in it is varied. The superficial gas flow rates are 10 lph, 15 lph, 20 lph and 25 lph. The characteristics of bubble after splitting which include its shape, size and velocity for various gas flow rates mentioned above are studied numerically and are compared with experimental results. These hydrodynamic characteristics play a pivotal role in the reactions occurring between the liquid and gas phases in the bubble column reactor.

• Periodical: Applied Mechanics and Materials (Volumes 813-814)
• Pages: 1023-1027
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.813-814.1023
• Online since: November 2015
• Authors: S. Arunkumar, V. Harshavardhan Reddy, T.M. Sreevathsav, M. Venkatesan*
• Keywords: ANSYS FLUENT, Bubble Column Reactor, Bubble Splitting, VOF

References

[1] W. Deckwer, Bubble column reactors - their modeling and dimensioning, Int. Chem. Engg, 19 (1979) 21-32.

[2] M. Simonnet, C. Gentric, E. Olmos, and N. Midoux, CFD simulation of the flow field in a bubble column reactor: Importance of the drag force formulation to describe regime transitions, Chemical Engineering and Processing: Process Intensification, 47 (2008).

DOI: 10.1016/j.cep.2007.08.015

[3] J. B. Joshi, Computational flow modelling and design of bubble column reactors, Chem. Eng. Sci. 56 (2001) 5893-5933.

DOI: 10.1016/s0009-2509(01)00273-1

[4] R. Masood, C. Rauh, and A. Delgado, CFD simulation of bubble column flows: An explicit algebraic Reynolds stress model approach, International Journal of Multiphase Flow, 66 (2014) 11-25.

DOI: 10.1016/j.ijmultiphaseflow.2014.06.008

[5] K. Ekambara, M. T. Dhotre, J. B. Joshi, CFD simulations of bubble column reactors: 1D, 2D and 3D approach, Chem. Eng. Sci. 60 (2005) 6733-6746.

DOI: 10.1016/j.ces.2005.05.047

[6] Y. Xua, M. Liua, C. Tanga, Three-dimensional CFD–VOF–DPM simulations of effects of low-holdup particles on single-nozzle bubbling behavior in gas–liquid–solid systems. Che. Eng. Sci. 222 (2013) 292-306.

DOI: 10.1016/j.cej.2013.02.065

[7] D. Ma, M. Liu ,Y. Zu, C. Tang, Two Dimensional volume of fluids simulation studies on single bubble formation and dynamics in bubble columns, Chemical Engineering Science, 72 (2012) 61-77.

DOI: 10.1016/j.ces.2012.01.013

[8] D. Jain, J. A. M. Kuipers, N. G. Deen, Numerical study of coalescence and breakup in a bubble column using a hybrid volume of fluid and discrete bubble model approach, Chemical Engineering Science, 119 (2014) 134-146.

DOI: 10.1016/j.ces.2014.08.026

[9] A. Akhtar, M. Tade, V. Pareek, Simulations of bubble column reactors using a volume of fluid approach: Effect of air distributor, Can. J. Chem. Eng. 85 (2007) 290-301.

DOI: 10.1002/cjce.5450850304