Hydrodynamics and Mass Transfer in a Concentric Internal Jet-Loop Airlift Bioreactor Equipped with a Deflector

Abstract

The gas–liquid hydrodynamics and mass transfer were studied in a concentric tube internal jet-loop airlift reactor with a conical bottom. Comparing with a standard design, the gas separator was equipped with an adjustable deflector placed above the riser. The effect of riser superficial gas velocity uSGR on the total gas holdup εGT, homogenization time tH, and overall volumetric liquid-phase mass transfer coefficient kLa was investigated in a laboratory bioreactor, of 300 mm in inner diameter, in a two-phase air–water system and three-phase air–water–PVC–particle system with the volumetric solid fraction of 1% for various deflector clearances. The airlift was operated in the range of riser superficial gas velocity from 0.011 to 0.045 m/s. For the gas–liquid system, when reducing the deflector clearance, the total gas holdup decreased, the homogenization time increased twice compared to the highest deflector clearance tested, and the overall volumetric mass transfer coefficient slightly increased by 10–17%. The presence of a solid phase shortened the homogenization time, especially for lower uSGR and deflector clearance, and reduced the mass transfer coefficient by 15–35%. Compared to the gas–liquid system, the noticeable effect of deflector clearance was found for the kLa coefficient, which was found approx. 20–29% higher for the lowest tested deflector clearance.

The Study of Fluid Dynamics Simulation of the Internal Flow Field in a Novel Airlift Oscillation Loop Bioreactor

“…Qiao et al [20] also designed a gas distributor capable of multiple injection directions to improve the gas-liquid dispersion performance in the airlift loop reactor. And Shi et al [21] analyzed a novel swirling demulsified airlift loop reactor for the treatment of refined soybean oil wastewater.…”

Measurement of Mass Transfer Intensity in Gas–Liquid Medium of Bioreactor Circuit Using the Thermometry Method

“…Among them lies a fair assessment of fermenters' performance indicators [19][20][21] for the case of the large-scale transition from laboratory to industrial solutions. Another indisputable challenge for researchers in the field of biotechnology is the development and implementation of analytical modules for the control system of mass transfer characteristics of the fermentation process [22][23][24][25]. Both of these problems require an adequate verified description of the behavior of bubbles in a two-phase gas-liquid medium of a bioreactor [26][27][28][29], in particular, the development of relevant experiments and methods for evaluating the mass transfer in the system [14,[30][31][32].…”