Liquid mixing in two- and three-phase airlift reactors

Aeration and mass transfer optimization in a rectangular airlift loop photobioreactor for the production of microalgae

“…Only in the regime III where a gas recirculation exists (Heijnen et al, 1997), the gas holdup both in the riser and the downcomer can be promoted with the increase of h tc (Kilonzo et al, 2006(Kilonzo et al, , 2007. This is why an increase of gas voidage was observed in IALR with the increase of top clearance (Chisti, 1989;Kilonzo et al, 2006Kilonzo et al, , 2007 and an opposite phenomenon is seen in this work and other publications (Lazarova et al, 1997;Liu et al, 2008;Lu et al, 1994).…”

“…Couvert et al (1999) argued that the top clearance has negligible effect on the gas holdup. Lazarova et al (1997), Liu et al (2008) and Lu et al (1994) stated that the gas voidage decreases with the increase of top clearance, while Chisti (1989), Kilonzo et al (2006) and Kilonzo et al (2007) drew a completely opposite conclusion. However, no further explanation has been made on it so far.…”

Experimental and theoretical analysis of axial dispersion in the liquid phase in external-loop airlift reactors

“…Most contributions are indeed based on the Blenke method (see, e.g., Blenke, 1979;Fields and Slater, 1983;Kochbeck and Hempel, 1994;Tudose, 1996, 1997;Merchuk et al, 1998) that considers an axial dispersion coefficient for the whole reactor. This method is probably suitable for internal-loop ALRs, for which deaeration is seldom complete, but this point is more doubtful in external-loop ALRs, as shown by Verlaan et al (1989), Lu et al (1994) and Dhaouadi et al (1997). These authors have suggested an analysis of mixing in each individual section, arguing that their respective role on mixing could be very different.…”

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

“…Note that the second and third peaks of the response curves are used to obtain t R and t D , since the first peak of the response curve obtained by the lower pH sensor in the riser is not well-established at a higher aeration rate [6].…”

“…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.…”