Using CFD simulations and statistical analysis to correlate oxygen mass transfer coefficient to both geometrical parameters and operating conditions in a stirred‐tank bioreactor

The acidic gas, Carbon dioxide (CO2) absorption in aqueous ammonia solvent was carried as an example for industrial gaseous treatment. The packed column was provided with a novel structured BX-DX packing material. The overall mass transfer coefficient was calculated from the absorption efficiency of the various runs. Due to the high solubility of CO2, mass transfer was shown to be mainly controlled by gas side transfer rates. The effects of different operating parameters on KGav including CO2 partial pressure, total gas flow rates, volume flow rate of aqueous ammonia solution, aqueous ammonia concentration, and reaction temperature were investigated. For a particular system and operating conditions structured packing provides higher mass transfer coefficient than that of commercial random packing.

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Determination of the ozone volumetric mass transfer coefficient in bubble column with two-fluid nozzle gas distributor

Hemijska industrija ◽

10.2298/hemind140716075d ◽

2015 ◽

Vol 69 (5) ◽

pp. 553-559 ◽

Cited By ~ 1

Author(s):

Milica Djekovic-Sevic ◽

Nevenka Boskovic-Vragolovic ◽

Ljiljana Takic ◽

Radmila Garic-Grulovic ◽

Srdjan Pejanovic

Keyword(s):

Mass Transfer ◽

Transfer Coefficient ◽

Mass Transfer Coefficient ◽

Bubble Column ◽

Operating Conditions ◽

Volumetric Mass Transfer Coefficient ◽

Gas Distributor ◽

Liquid Mass Transfer ◽

Two Fluid

Experimental investigation of gas-liquid mass transfer of ozone in water, in bubble column with two-fluid nozzle gas distributor (BKDM), under different operating conditions, are presented in this work. The main objective was to determine the ozone volumetric mass transfer coefficient, kL a, in calm uniform section of the column, under different values of gas and liquid flow rates. Obtained values of these coefficients were compared with the values in countercurrent bubble column. The critical liquid flowrate, when gas hold up reaches its maximum, was experimentally determined. It was shown that the maximum value of the ozone volumetric mass transfer coefficient is obtained just when liquid flowrate is at its critical value.

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Application of Scale-Up Criterion of Constant Oxygen Mass Transfer Coefficient (kLa) for Production of Itaconic Acid in a 50 L Pilot-Scale Fermentor by Fungal Cells of Aspergillus terreus

Journal of Microbiology and Biotechnology ◽

10.4014/jmb.1307.07084 ◽

2013 ◽

Vol 23 (10) ◽

pp. 1445-1453 ◽

Cited By ~ 14

Author(s):

Woo-Shik Shin

Keyword(s):

Mass Transfer ◽

Transfer Coefficient ◽

Mass Transfer Coefficient ◽

Itaconic Acid ◽

Aspergillus Terreus ◽

Scale Up ◽

Pilot Scale ◽

Oxygen Mass Transfer

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Optical Approach for Measuring Oxygen Mass Transfer in Stirred Tank Bioreactors

International Journal of Chemical Reactor Engineering ◽

10.1515/ijcre-2016-0209 ◽

2017 ◽

Vol 15 (4) ◽

Author(s):

Jorge Isaac Martínez-Corona ◽

Rubén Rogelio Cisneros-Garza ◽

Felipe Robledo-Padilla ◽

Roberto Parra-Saldívar ◽

Andrés Sebastián Treviño-Martínez ◽

...

Keyword(s):

Mass Transfer ◽

Bubble Diameter ◽

Real Life ◽

Digital Camera ◽

Close Correlation ◽

Stirred Tank ◽

Oxygen Mass Transfer ◽

Stirred Tank Bioreactor ◽

Sensing Systems ◽

And Control

Abstract Bioreactor engineering allows modeling the conditions of real life biological processes. Particularly, oxygen represents one of the most important factors for life, and the understanding and control of its mass transfer in bioreactors is one of the most challenging problems in the industry. The aim of this study was to develop an optical approach for measuring the oxygen mass transfer coefficient (kLa). An assembly was constructed for this purpose, consisting of a stirred tank bioreactor, a high-intensity light source, a luminometer and a digital camera. Air flux supply and stirring velocity of the bioreactor were tested over a range of thirty-five values. The air bubbles generated were counted and their diameters were measured from photographs. The luminometer measured light obstruction due to bubbles. A polarography electrode sensor measured the dissolved oxygen in water to correlate it with the optical approach. The results showed a close correlation between kLa and light obstructed due to bubbles of air. The bubble diameter and holdup results suggest that the size of the bubbles decreases and becomes more homogeneous as stirring speed increases. A multivariable linear model for kLa as a function of the measured light obstruction and air flux injection was constructed. A strong correlation between this model and results was obtained. This approach avoids the need for chemical sensors for sensing systems, with a noninvasive and nondestructive methodology to determine the kLa for dilute solutions. This technique could be developed to evaluate a scaled-up bioreactor before running a bioprocess.

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