title: Hydrodynamic characteristics and gas-liquid mass transfer in a biofilm airlift suspension reactor.
abstract: The hydrodynamics and mass transfer, specifically the effects of gas velocity and the presence and type of solids on the gas hold-up and volumetric mass transfer coefficient, were studied on a lab-scale airlift reactor with internal draft tube. Basalt particles and biofilm-coated particles were used as solid phase. Three distinct flow regimes were observed with increasing gas flow rate. The influence of the solid phase on the hydrodynamics was a peculiar characteristic of the regimes. The volumetric mass transfer coefficient was found to decrease with increasing solid loading and particle size. This could be predominantly related to the influence that the solid has on gas hold-up. The ratio between gas hold-up and volumetric mass transfer coefficient was found to be independent of solid loading, size, or density, and it was proven that the presence of solids in airlift reactors lowers the number of gas bubbles without changing their size. To evaluate scale effects, experimental results were compared with theoretical and empirical models proposed for similar systems.
authors: Kluyver Institute for Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands. c.nicolella@ic.ac.uk
authors: C
authors: C
authors: Nicolella
authors: M C
authors: MC
authors: van Loosdrecht
authors: R G
authors: RG
authors: van der Lans
authors: J J
authors: JJ
authors: Heijnen
mesh_terms: D018441:Biofilms; D020099:Coated Materials, Biocompatible; D005740:Gases / Q000737:chemistry; D008962:Models, Theoretical; D010100:Oxygen / Q000032:analysis; D010316:Particle Size; D012212:Rheology; D013499:Surface Properties
chemical_list: D020099:Coated Materials, Biocompatible; D005740:Gases; D010100:Oxygen