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

Abstract

Hydrodynamic and gas-liquid mass transfer characteristics, such as liquid velocity, gas holdup, solid holdup and gas-liquid volumetric mass transfer coefficient, in the riser and downcomer of the gas-liquid-solid three-phase internal loop airlift bioreactors with complete gas recirculation for non-Newtonian fluids, were investigated. A mathematical model for the description of flow behavior and gas-liquid mass transfer of these bioreactors was developed. The predicted results of this model agreed well with the experimental data.

Prediction of gas holdup in a combined loop air lift fluidized bed reactor using Newtonian and non-Newtonian liquids

“…Figure 7 shows the effect of fluid consistency index for 0.25, 0.6 and 1.0% CMC liquids for the superficial gas velocity 0.001132 m/s. It is observed from Figure 7 that an increase in fluid consistency index (K) of liquid decreases the gas hold-up; this may be due to the formation of large bubbles at higher concentrations of solutions, the same trend was also observed in the literature studies [12,13].…”

Prediction of gas holdup in a combined loop air lift fluidized bed reactor using Newtonian and non-Newtonian liquids

“…Figure 7 shows the effect of fluid consistency index for 0.25, 0.6 and 1.0% CMC liquids for the superficial gas velocity 0.001132 m/s. It is observed from Figure 7 that an increase in fluid consistency index (K) of liquid decreases the gas hold-up; this may be due to the formation of large bubbles at higher concentrations of solutions, the same trend was also observed in the literature studies [12,13].…”

Mixing characteristics of draft tube airlift bioreactor using the electrical resistance tomography

“…5.2.4). These observations and results are in agreement with results reported by Wen et al (2005), Onken and Weiland (1980) and Fields et al (1984).…”

“…They also reported that the gas holdup gradually decreased with increasing viscosity, since an increase in viscosity shortened the residence time of gas bubbles. This observation concurs with results obtained using CMC for 3 phase flow in an internal loop with draft tube (Wen et al, 2005).…”

Characteristics of Local Flow Dynamics and Macro-Mixing in Airlift Column Reactors for Reliable Design and Scale-Up

“…This was in agreement with Lu et al (1994) who also reported superior mixing in a two phase system compared to a three phase system. In a similar three phase system using CMC, Wen et al (2005) confirmed that when U g increased, ε g and U l in both regions also increased as suggested previously (Hwang et al, 1997). Furthermore, bubbles coalesced and reduced the gas holdup, although gas holdup values were similar for water and salt solutions.…”

Prediction of gas holdup in a combined loop air lift fluidized bed reactor using Newtonian and non-Newtonian liquids

“…Figure 7 shows the effect of fluid consistency index for 0.25, 0.6 and 1.0% CMC liquids for the superficial gas velocity 0.001132 m/s. It is observed from Figure 7 that an increase in fluid consistency index (K) of liquid decreases the gas hold-up; this may be due to the formation of large bubbles at higher concentrations of solutions, the same trend was also observed in the literature studies [12,13].…”

Mixing characteristics of draft tube airlift bioreactor using the electrical resistance tomography

“…5.2.4). These observations and results are in agreement with results reported by Wen et al (2005), Onken and Weiland (1980) and Fields et al (1984).…”

“…They also reported that the gas holdup gradually decreased with increasing viscosity, since an increase in viscosity shortened the residence time of gas bubbles. This observation concurs with results obtained using CMC for 3 phase flow in an internal loop with draft tube (Wen et al, 2005).…”

Characteristics of Local Flow Dynamics and Macro-Mixing in Airlift Column Reactors for Reliable Design and Scale-Up

“…This was in agreement with Lu et al (1994) who also reported superior mixing in a two phase system compared to a three phase system. In a similar three phase system using CMC, Wen et al (2005) confirmed that when U g increased, ε g and U l in both regions also increased as suggested previously (Hwang et al, 1997). Furthermore, bubbles coalesced and reduced the gas holdup, although gas holdup values were similar for water and salt solutions.…”

Prediction of gas holdup in a combined loop air lift fluidized bed reactor using Newtonian and non-Newtonian liquids

“…Figure 7 shows the effect of fluid consistency index for 0.25, 0.6 and 1.0% CMC liquids for the superficial gas velocity 0.001132 m/s. It is observed from Figure 7 that an increase in fluid consistency index (K) of liquid decreases the gas hold-up; this may be due to the formation of large bubbles at higher concentrations of solutions, the same trend was also observed in the literature studies [12,13].…”

Mixing characteristics of draft tube airlift bioreactor using the electrical resistance tomography

“…5.2.4). These observations and results are in agreement with results reported by Wen et al (2005), Onken and Weiland (1980) and Fields et al (1984).…”

“…They also reported that the gas holdup gradually decreased with increasing viscosity, since an increase in viscosity shortened the residence time of gas bubbles. This observation concurs with results obtained using CMC for 3 phase flow in an internal loop with draft tube (Wen et al, 2005).…”

Characteristics of Local Flow Dynamics and Macro-Mixing in Airlift Column Reactors for Reliable Design and Scale-Up

“…This was in agreement with Lu et al (1994) who also reported superior mixing in a two phase system compared to a three phase system. In a similar three phase system using CMC, Wen et al (2005) confirmed that when U g increased, ε g and U l in both regions also increased as suggested previously (Hwang et al, 1997). Furthermore, bubbles coalesced and reduced the gas holdup, although gas holdup values were similar for water and salt solutions.…”