Analysis of hydrodynamic effects on biofilm thickness in fluidized-bed tapered bioreactors--颗粒学报PARTICUOLOGY

Koerich, D. M., & Rosa, L. M. d. (2021). Analysis of hydrodynamic effects on biofilm thickness in fluidized-bed tapered bioreactors. Particuology, 58, 48-57. https://doi.org/10.1016/j.partic.2021.01.011

Analysis of hydrodynamic effects on biofilm thickness in fluidized-bed tapered bioreactors

Daniela Maria Koerich, Leonardo Machado da Rosa ^*

Chemical Engineering Department, University of Blumenau (FURB), 3250 São Paulo Street, 89030-000 Blumenau, Santa Catarina, Brazil

10.1016/j.partic.2021.01.011

Volume 58, October 2021, Pages 48-57

Received 16 May 2020, Revised 8 November 2020, Accepted 19 January 2021, Available online 2 March 2021, Version of Record 17 March 2021.

E-mail: lmrosa@furb.br

Highlights

• Three-dimensional simulations of turbulent two-phase flows were carried out.

• Characteristics of the fluidized bed for tapered bioreactors were analyzed.

• The resulting fluidization curves showed good agreement with experimental data.

• The turbulence in fluid flow is more intense than bioparticles turbulence.

• Bioparticles collisions and shear stress effects on biofilm thickness were modeled.

Abstract

Fluidized beds in tapered geometries provide advantages such as a broad range of optimum operating conditions. However, the dynamics of the flow inside these bioreactors is significantly more complex, as they promote non-uniform bioparticles distribution. To this end, the CFD technique can give a detailed description of the flow in the bioreator. Hence, the aim of this work is to assess the influence of the hydrodynamic on the steady-state biofilm thickness through numerical simulations of liquid–solid fluidized bed. Two geometries of tapered bioreactors in the operating conditions used to develop biofilms. Simulations were run to solve the two-phase RANS equations using the open-source software OpenFOAM in transient-state. The SST k − ω model was used to estimate the turbulent features of the flow. Velocity and bioparticles distribution inside the reactor were analyzed for different inlet velocities, while bioparticles collision frequency and shear stresses were evaluated for various operating conditions. The comparison between the turbulent kinetic energy and the granular temperature indicated that the fluid flow is more turbulent than the bioparticles movement. The hydrodynamics influence on the steady-state biofilm thickness was assessed, and results led to the conclusion that biofilm is more sensitive to hydrodynamic shear stress than bioparticles collisions.

Graphical abstract

Keywords

Liquid–solid fluidization; Shear stress; Particles collisions; Computational fluid dynamics; Biofilm; Tapered bioreactors

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