scholarly journals Hydrodynamic Considerations in Bioreactor Selection and Design

Author(s):  
Enes Kadic ◽  
Theodore J. Heindel

The biological production of renewable fuels and chemicals, medicines, and proteins is not possible without a properly functioning bioreactor. Bioreactors are expected to meet several basic requirements and create conditions favorable to the biological material such that the desired production is maximized. The basic requirements, which are strongly influenced by fluid mechanic principles, may include minimum damage to the biological material, maximum reactor volume utilization, optimized gas-liquid mass transfer, and/or enhanced mass transfer from the liquid to the biological species. Each of these goals may be achieved within any of the major bioreactor designs, which generally fall under the categories of stirred tank, bubble column, or airlift bioreactor. Yet, each of the bioreactor designs has strengths and weaknesses. This paper provides an overview of bioreactor hydrodynamic developments and the fluid mechanic issues that should to be considered when selecting a bioreactor for experimental and production purposes.

Author(s):  
Lei Wang ◽  
Xiao Xu ◽  
Hualin Wang ◽  
HongLai Liu ◽  
Qiang Yang

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.


2015 ◽  
Vol 69 (5) ◽  
pp. 553-559 ◽  
Author(s):  
Milica Djekovic-Sevic ◽  
Nevenka Boskovic-Vragolovic ◽  
Ljiljana Takic ◽  
Radmila Garic-Grulovic ◽  
Srdjan Pejanovic

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.


2016 ◽  
Vol 39 (5) ◽  
pp. 945-952 ◽  
Author(s):  
Xiangyang Li ◽  
Pingping Li ◽  
Liangzhu Zu ◽  
Chao Yang

2012 ◽  
Vol 66 (9) ◽  
pp. 1914-1922 ◽  
Author(s):  
Takuro Kobayashi ◽  
Kai-Qin Xu ◽  
Yu-You Li ◽  
Yuhei Inamori

Biological desulfurization using a bubble column reactor was investigated in a continuous biogas treatment. Rapid biogas circulation between the digester and the bubble column for biological desulfurization was used to stimulate the gas–liquid mass transfer of H2S. A positive correlation between the biogas circulation rate and H2S removal rate was observed. Moreover, the increase in the circulation rate stimulated the O2 mass transfer, eventually translating into an increase in sulfate production from the oxidation of H2S. Throughout the continuous experiment, the reactor retained sufficient levels of sulfide-oxidizing bacteria. A comparison of the results of the continuous biogas treatment and batch tests suggests that the gas–liquid mass transfer rate of H2S was the rate-limiting step in the biological desulfurization in the reactor, indicating that the mass transfer efficiency of H2S needs to be improved to enhance the desulfurization performance.


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