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

Abstract

The development of energy-efficient solutions for large-scale fermenters demands a deep and comprehensive understanding of hydrodynamic and heat and mass transfer processes. Despite a wide variety of research dedicated to measurements of mass transfer intensity in bubble flows, this research subject faces new challenges due to the topical development of new innovative bioreactor designs. In order to understand the fluid dynamics of the gas–liquid medium, researchers need to develop verified CFD models describing flows in the bioreactor loop using a progressive physical and mathematical apparatus. In the current paper, we represent the results of evaluating the key performance indicator of the bioreactor, namely the volumetric mass transfer coefficient (kLa) known as a parameter of dominant importance for the design, operation, scale-up, and optimization of bioreactors, using the developed thermometry method. The thermometry method under consideration was examined within a series of experiments, and a comparative analysis was provided for a number of various regimes also being matched with the classical approaches. The methodology, experiment results, and data verification are given, which allow the evaluation of the effectiveness and prediction of the fluid flows dynamics in bioreactors circuits and ultimately the operational capabilities of the fermenter line.

Assessing the Mass Transfer Coefficient in Jet Bioreactors with Classical Computer Vision Methods and Neural Networks Algorithms

“…Thus, for k L a calculations the methods presented in [8,51,52] might be used. The observed and real areas of phase contact should be compared based on experimental data, then the coefficient k L can also be found experimentally or theoretically by analyzing the chemical components of the liquid.…”

“…The key process determining the bioreactors' efficiency is the transfer of the gas phase through the gas-liquid interface. The gas flow from gas bubbles into liquid is known to be a function of two important parameters: the surface area of the phase separation a and the mass transfer coefficient k L [8]. These two parameters are usually combined into the volumetric mass transfer coefficient k L a [9][10][11].…”

“…This understanding can only be achieved if the hydrodynamic and physical mechanisms which are responsible for these gradients are understood in detail through experimental and numerical tools. There are various methods for measuring k L in general [8,20,21] allowing mass transfer to be measured as a complex phenomenon; however, the measurement of individual components, namely the interfacial area a, is of particular interest, since it allows determination of the factors that specifically affect the interfacial surface known as the most important component of the mass transfer process when aiming to achieve high efficiency of technological processes based on the mass transfer.…”

Influence of the gas–liquid non-equilibrium media structure on the mass transfer dynamics in biophysical processes

“…Worth mentioning that the chosen measurement method using the gassing out procedure involves working over a wide range of diffusion driving forces from 0 up to C * O2 . This is a significant breakthrough when being compared with the previous results obtained from measurements of k L [48] by the chemical sulfite oxidation and thermometry methods for a similar bioreactor, since these methods involve maintaining the greatest diffusion driving force in the medium.…”

Computer Vision Algorithm for Characterization of a Turbulent Gas–Liquid Jet

“…Jet stream bioreactors [12,13] represent a type of machine with the recirculation of the liquid and gas phases caused by generated multiscale gas-liquid jets with a high volume content of gas bubbles. The behavior of the jet can be characterized as a high-turbulence physical process, frequently leading to technical problems related to flow control, analyzing its parameters, and further optimizing design elements such as the nozzle and jet pump.…”