Volumetric Mass Transfer Coefficient of Oxygen in An Internal Loop Airlift Reactor with a Convergence-Divergence Draft Tube

Abstract

Experimental measurements of hydrodynamics and the volumetric mass transfer coefficient of oxygen (VMTCO) in an internal loop airlift reactor with different types of draft tubes are reported for the two‐phase systems, air/water and air/carboxyl methyl cellulose (CMC) solution, and a three‐phase system, air/water/resin particle, respectively. The properties of convergence‐divergence draft tubes with three different structural parameters are compared with those of the conventional column draft tube. The results indicate that gas holdups in convergence‐divergence draft tubes are higher than those in conventional draft tubes, the volumetric mass transfer coefficient of oxygen increases with increasing superficial air flow rates. The convergence‐divergence draft tubes all show higher mass transfer capacity than the traditional ones. A 10% higher mass transfer coefficient is observed for the three structural parameters. In the air/CMC system, the volumetric mass transfer coefficient of oxygen decreases with increasing bulk viscosity, while in the three‐phase system VMTCO increases with the resin particle loading. The correlation equation of the volumetric mass transfer coefficient with the operating conditions and structural parameters is established.

Bioreactors: Airlift Reactors

“…The authors reported that the changes in cross section in the riser produced an increase in the gas holdup. An analogous study was accomplished by Wei et al (377,378), but in an IL-ALR in which different convergence-divergence draft tubes were employed. The coalescence and distribution of bubbles were considerably affected and the gas holdup was much higher than that in a conventional draft tube ALR.…”

Contrasting microbial community composition and function perspective in sections of a full-scale coking wastewater treatment system

“…In order to deal with high COD load rate (2.13 kg COD m −3 day −1 ), an internal-loop multiphase airlift fluidized bed reactor was developed by the authors (Wei et al 2000) and applied in the current system. The internal-loop design ensured the efficient mixing and mass transfer with low energy consumption (Zhang et al 2012a).…”

Gas holdup, bubble behavior and mass transfer in a 5m high internal-loop airlift reactor with non-Newtonian fluid

“…There were more large bubbles in the viscous liquid. Large bubbles had a short residence time, thus led to a decrease in the gas holdup [34]. It should be noted that the gas holdups in 0.4 wt% and 0.45 wt% CMC solutions were quite similar at U g ≤ 6 cm/s.…”