Gas-liquid mass transfer in an internal loop airlift reactor with low density particles

Hydrodynamic characteristics and gas–liquid mass transfer in a biofilm airlift suspension reactor

“…Also, in the case of solids of lower density, gas hold-up was found to decrease with increasing solid loading, as reported by Miyahara and Kawate (1993) for plastic beads ( S ‫ס‬ 1043 to 1135 kg/m 3 ), by Hwang and Lu (1997) for polystyrene cylinders ( S ‫ס‬ 1050 kg/m 3 ), and by Lu et al (1995) for calcium-alginate beads ( S ‫ס‬ 1030 kg/m 3 ). The effect of solid is particularly noticeable at low gas velocity, as observed by Livingston and Zhang (1993), whose hydrodynamic model of a three-phase airlift reactor is consistent with the data of Koide et al (1985).…”

“…The influence of the presence of solids has been reported for various types of particles including glass beads (Koide et al, 1985), plastic beads (Miyahara and Kawate, 1993), polystyrene cylinders (Hwang and Lu, 1997), activated carbon particles (Muroyama et al, 1985) Raney nickel particles (Gavroy et al, 1995), and calcium-alginate beads (Lu et al, 1995). For the case of biofilm-coated particles, Ryhiner et al (1986) reported that the gas-liquid volumetric mass transfer coefficient in a three-phase biofilm fluidized sand-bed reactor decreased (in the range 0.02 to 0.04 s −1 ) with increasing amounts of clean sand and was almost independent of the sand fraction with biofilm-covered sand.…”

Characteristics of three-phase internal loop airlift bioreactors with complete gas recirculation for non-Newtonian fluids

“…Hydrodynamics such as liquid circulation velocity, gas holdup and solid holdup and the gas-liquid volumetric mass transfer coefficient are the most important parameters used in assessing the above airlift bioreactors. Several investigators have experimentally studied hydrodynamics such as the liquid velocity in the riser and downcomer and/or the overall gas-liquid volumetric mass transfer of the three-phase internal loop airlift bioreactors for the Newtonian fluids [4][5][6][7][8]. Van Benthum et al [9][10][11] discussed the three regimes and hydrodynamic characteristics of the two-and three-phase airlift reactors they developed: the biofilm airlift suspension extension (BASE) reactor.…”

Bioreactors: Airlift Reactors

“…The mathematical model and consequently the analysis of the experimental data become much more complicated in this case. Nevertheless, this approach has been used (81,129,245,246), and the mass transfer experiments render in this case the k L a for each of the regions of the ALR. Figure 25 shows the results reported by Hwang and Lu (246) in an IL-ALR.…”

“…In some of the papers in Table 9, the problem of gas/liquid mass transfer is addressed and is given more attention than fluid dynamics: Hwang and Lu (246), Tobajas et al (412), and Camacho-Rubio et al (423). Hwang and Lu (246) present an analysis of ''gassing out'' experiments, where a different value of the mass transfer coefficient k L a is considered in each of the three distinct regions: riser, downcomer, and separator.…”