Effects of the hydrodynamic environment and oxygen mass transfer on plant cell growth and milk-clotting protease production in a stirred-tank reactor

2012 ◽  
Vol 12 (4) ◽  
pp. 441-449 ◽  
Author(s):  
Sara Raposo ◽  
Maria Emília Lima-Costa
Keyword(s):  
Mass Transfer ◽  
Cell Growth ◽  
Plant Cell ◽  
Stirred Tank ◽  
Protease Production ◽  
Oxygen Mass Transfer ◽  
Tank Reactor ◽  
Milk Clotting ◽  
Milk Clotting Protease ◽  
Hydrodynamic Environment

scholarly journals Circulating Jet for Enhancing the Mass Transfer in a Gas-liquid Stirred Tank Reactor

2021 ◽  
Author(s):  
Lei Wang ◽  
Xiao Xu ◽  
Hualin Wang ◽  
HongLai Liu ◽  
Qiang Yang
Keyword(s):  
Mass Transfer ◽  
Scale Up ◽  
Input Power ◽  
Stirred Tank ◽  
Exhaust Gas ◽  
Stirred Tank Reactor ◽  
Tank Reactor ◽  
Mass Transfer Efficiency ◽  
Low Mass ◽  
Liquid Mass Transfer

A gas-liquid stirred tank reactor (STR) has some problems, such as low mass transfer efficiency, high exhaust gas oxygen concentration, and low product conversion rate, due to limitations of stirring speed and input power. This article proposes a method to enhance the gas-liquid mass transfer in a STR using circulating jet internals. When a circulating jet is added, the average bubble size in the reactor is reduced to 1.26 mm, and the overall gas holdup is increased to 8.23%, which is an increase of 3.62 times of the original STR. The gas-liquid volumetric mass transfer coefficient is increased to 0.05556 s-1, which is 4.84 times of the original STR. The unit volume power is increased by only 1.4 times. These data provide references for the design and scale-up of new jet STRs.

Optical Approach for Measuring Oxygen Mass Transfer in Stirred Tank Bioreactors

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.

Mass transfer at the outer surface of a spiral tube heat exchanger in a stirred tank reactor and possible applications

2021 ◽  
Vol 165 ◽  
pp. 426-434
Author(s):  
Samah Mustafa ◽  
Mahmoud M. Taha ◽  
Ahmed A. Zatout ◽  
Gomaa H. Sedahmed ◽  
Dina A. El-Gayar
Keyword(s):  
Mass Transfer ◽  
Heat Exchanger ◽  
Outer Surface ◽  
Stirred Tank ◽  
Spiral Tube ◽  
Stirred Tank Reactor ◽  
Tube Heat Exchanger ◽  
Tank Reactor
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